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What are cdi and tdi. The most reliable Volkswagen diesel engines according to owner reviews. general analysis, pros and cons of the motor

The 1.9 TDI (ALH) engine was produced from approximately 1997 to 2006. It can be found on VAG cars belonging to the budget segments. In particular, the 1.9 TDI (ALH) engine was widely used in the first generations of Skoda Octavia and Seat Leon. It can also be found under the hoods of Volkswagen Golf 4, Bora/Jetta, New Beetle, Caddy, Polo and even Ford Galaxy and Audi A3. This power unit develops 90 hp. at 3750 rpm and 210 Nm at 1900 rpm.

The fuel system of the 1.9 TDI engine (ALH) is based on a distribution injection pump. There is no question of any pump injectors and, especially, Common Rail.

1.9 TDI (ALH) - it's simple and reliable

This engine is valued for its simple and reliable design “originally from the 1990s”. Only, unlike its ancestors, this engine was equipped with a turbine with variable guide vane geometry and an EGR system.

The 1.9 TDI (ALH) engine also has simpler modification, indicated by the index AGR. This option develops the same torque and power (90 hp), only its peak occurs at 4000 rpm. AGR motor conditionally even more budgetary: initially it was equipped with a simple single-mass flywheel, whereas ALH was always dual-mass. By the way, the AGR began to be equipped with a dual-mass flywheel, starting with the 100,001st copy.

The engines also differ in turbines. If the ALH has a turbine with advanced control and variable geometry, then the AGR turbine is simpler, without geometry and is controlled through a bypass valve. Notorious the boost control valve (N75) is present on both engines. Only on ALH it controls the vacuum drive-actuator of the turbine geometry, on AGR it controls the pressure that opens the bypass valve.

The 1.9 TDI (ALH) engine can be purchased at a favorable price from the MotorLand company with a guarantee.

Engine problems 1.9TDI (ALH), or how to kill one of the most resourceful engines

Frank design problems or defects in the 1.9 TDI engine (ALH and AGR) generally not. All problems of these engines arise for simple reasons: due to the lack of normal maintenance and general neglect of the power unit. To extend the service life (and the service life of this motor easily exceeds 500,000 km) of the ALH engine, you need to periodically:

carry out computer diagnostics;
check the performance of the injection pump and injectors;
clean the intake manifold of carbon deposits, soot and oily deposits;
monitor the condition of the turbine.

In general, almost all the troubles of the 1.9 TDI (ALH) engine lie in the EGR system and turbine.

1.9 TDI (ALH) engine does not start

Often the 1.9 TDI (ALH) engine refuses to start. The first step is to check the flap located in the EGR valve. This valve (usually called a throttle valve, although in fact it is designed to limit the flow of air to add exhaust gases entering through the EGR valve) is actually designed to ensure that the diesel engine shuts down smoothly after turning off the ignition: it closes the intake manifold, in the absence of inflow air, the engine stops smoothly.

If the throttle is stuck in the closed position due to soot, the engine will not start. The stem of this damper is easily accessible, in most cases it can be opened manually by simply pressing on the stem. If the engine starts, the entire EGR valve must be removed and cleaned of carbon deposits.

1.9 TDI (ALH) engine does not develop power

Often the 1.9 TDI (ALH) engine stops pulling and developing normal power. This usually happens suddenly after accelerating to 130 km/h or above. After reducing speed, the engine stops developing normal power and responds sluggishly to the accelerator. Such symptoms indicate that the “geometry” of the turbine is “stuck” in the position of the minimum angle of attack of the blades, which exactly corresponds to the high load mode (when there is enough exhaust gas flow to the turbine wheel to ensure high turbine performance). There are several reasons why the geometry mechanism freezes:

you need to check its functionality. This is done with the engine running at idle speed. You need to disconnect the vacuum tube from the actuator (pneumatic valve, “fungus”) of the geometry drive, and then put it in place. In this case, the actuator rod should go down when disconnecting the tube, and after putting on the tube it should smoothly go up. If nothing like this happens: the rod does not move or moves jerkily, then the geometry mechanism is worn out. It is best to send the turbine for restoration.
if the “geometry” works normally, then you need to move on to computer diagnostics and run a check of the “basic settings” of the turbine control. The system will check the functionality of the boost control valve (valve N75), which controls the same pneumatic valve. If the actuator rod does not move, then the fault should be looked for in the N75 valve or in the hoses. There are three of these tubes: vacuum, “atmospheric” and turbine control (it is connected directly to the pneumatic valve). All tubes tend to fray. If there is a vacuum leak, then the turbine geometry does not move to the position of the maximum angle of attack of the guide vanes and the turbine is “under-inflated”. If there is a leak in the atmospheric tube, then the “geometry” of the turbine cannot go into the minimum angle of attack mode, and as a result, the turbine “overblown” occurs, which is felt during acceleration and high engine loads. In this case, the turbine control system, in the event of high deviations from the normal pressure in the intake manifold, commands valve N75 to move the turbine blades to the minimum angle of attack position, thereby reducing the intake pressure. Engine power drops. If you turn off the engine and start it again, the emergency turbine control mode is disabled. But only until the boost pressure again deviates from the norm.
A decrease in engine power occurs when the intake manifold loses its tightness. Usually a hole is formed in the intercooler through which air is released.

The 1.9 TDI (ALH) engine produces excess power

But the opposite situation, when the 1.9 TDI (ALH) engine suddenly starts to drive very quickly, usually ends in serious trouble. But first, there are two things to note about “driving fast”:

The turbine geometry can suddenly become stuck in a position that produces high boost pressure.
after installing a new, working turbine, the engine can return to its original boost and power parameters.

In the situations described above, the following occurs: normal or high flow of air compressed by the turbine blows oil out of the intercooler, which had been accumulating there for months.

Where does the oil in the intercooler come from? As a rule, all turbodiesels “send” some portions of oil into the intake. But an excess amount of oil in the intake and in the intercooler in particular appears there due to wear of the turbine cartridge. And the engine can run on this oil, but not for long. The oil, picked up by a fast flow of air compressed by the turbine, enters the combustion chambers, and the engine speed increases sharply, as if at maximum fuel supply. But at the same time, there is simply no limiter for the supply of this alternative fuel, and the oil literally flows into the cylinders and burns there.

At the same time, the speed of the motor increases to the limit. The engine is either destroyed(with connecting rods coming off and so on) or jams due to overheating. There are times when so much oil enters the cylinders that water hammer occurs. Actually, “overrun” is the only reason why the 1.9 TDI (ALH) engine “dies”. There are known cases when the engine went into disarray due to a new and fully working turbine, which was installed without first cleaning the intake manifold.

Serious damage to the 1.9 TDI (ALH) engine is rarely caused pouring injectors or faulty fuel injection pump. Due to excess fuel supply to the cylinders pistons burn out. However, a problem with fuel supply can be noticed in advance by increased consumption and problems with starting the engine.

In general, the 1.9 TDI (ALH) engine turned out to be relatively simple and reliable. Problems with it arise due to age, mileage, savings on maintenance, diagnostics and ignoring incipient problems with the turbine. If this engine still fails, you can buy a 1.9 TDI (ALH) unit for Skoda Octavia, Volkswagen Golf and other cars from the MotorLand company.

The TDI family of engines is a line of diesel power units produced by the German auto giant Volkswagen. Diesel engines, designated by the abbreviation TDI (Turbocharged Direct Injection), are units with a turbocharger and are equipped with a direct fuel injection system. These internal combustion engines can be found on various diesel car models, the manufacturers of which are part of the WAG concern (Audi, Volkswagen, Skoda, etc.)

Read in this article

The history of the TDI engine

The diesel engine has always attracted various companies with its untapped potential. The main task set before the engineers was to transform a noisy, low-speed and low-speed unit into a motor that could be easily installed in passenger cars. The result was the creation of a powerful, economical and environmentally friendly diesel engine, which in its performance characteristics was as close as possible to a gasoline power unit.

The pioneer in this direction was the Audi company, which back in 1980 installed a 1.6-liter diesel 54-horsepower engine under the hood of its popular Audi 80 model. Further improvement and development of technology led to the fact that already in 1989 Audi was the first in the world to establish and launched into mass production a compact, high-torque and powerful turbodiesel engine, which received the designation TDI, widely known today.

The first TDI was a 5-cylinder diesel engine, had a displacement of 2.5 liters, and was equipped with a turbocharger with an intercooler (charge air intercooling system). The maximum power of this engine was 120 hp. The torque indicator was at around 256 Nm and was achieved at 2250 rpm.

Since its appearance on the market, this power unit has become quite popular, as it was a worthy alternative not only to diesel engines from other manufacturers, but was also quite capable of competing with gasoline engines. Audi's TDI provided excellent dynamics, while fuel consumption was significantly lower compared to other analogues.

Features and benefits of the TDI engine

After Audi joined WAG, the Volkswagen concern took first place in the list of diesel engine manufacturers. Innovative engineering solutions and proven production technologies provided TDI engines with:

low noise level during operation;
high torque;
low fuel consumption;
reduction of exhaust gas toxicity;

Today, the TDI diesel engine has a number of advantages compared to its analogues, among which fuel efficiency and efficiency are highlighted. One of the main advantages is deservedly considered to be higher injection pressure compared to the performance of other systems. The injection pressure in TDI engines is at around 2050 bar, while analogues produce only 1350 bar.

In TDI, the injector is combined with a pump, which allows for maximum control over all fuel injection processes. This solution provides the TDI engine with high torque, as well as flexible operation of this diesel engine in different modes. Thanks to this fuel supply system, the combustion process of diesel fuel in TDI engines is more uniform and occurs “delicately,” that is, with minimal shock loads. For this reason, the noise level during diesel operation has significantly decreased, and the content of nitrogen oxide in the exhaust gases has also dropped. In other words, the TDI diesel engine is powerful, quiet, least harmful to the environment and the most economical engine among diesel power units available on the market.

Reliability of diesel TDIs

The installation of turbocharging allowed the diesel engine to develop more power, and the diesel efficiency also increased. As for TDI engines, these engines are quite reliable if used correctly. The health of these internal combustion engines is most strongly influenced by the quality of the fuel and timely maintenance. With proper care, the engine itself can even turn out to be a “millionaire”.

The weak point of TDI is the injectors and turbocharger. The service life of the injectors directly depends on the quality of the diesel fuel and the general condition of the TDI diesel power system. The service life of the turbine can vary, the average resource is 120-160 thousand km.

Fuel injection in TDI engines

In the early stages of the development of diesel internal combustion engines, the pressure in the system, which involves the presence of a fuel injection pump in conjunction with simple mechanical injectors, was only 20-40 bar. A modern diesel engine has a minimum pressure of 1600 Bar and higher. The tendency to increase fuel injection pressure is due to the fact that diesel engines have a very short time allotted for the mixture formation process.

If the crankshaft rotates at 2000 rpm, then only 3-4 milliseconds are allocated to mix a portion of diesel fuel with air. Increasing the crankshaft speed further shortens this time period. Also, the preparation of a homogeneous fuel-air mixture becomes possible only by increasing the injection pressure. In the case of low pressure, the fuel mixture will be of poor quality, and the combustion process will be low efficient. The result is increased toxicity of diesel exhaust and low efficiency.

Previously, the fuel injection pump on diesel engines was responsible for fuel injection, which works in tandem with mechanical injectors; today, common rail systems are installed on diesel engines. Since the combustion process in a diesel engine is an explosion from the contact of a portion of diesel fuel with air heated during the compression stroke, the injection time is very limited.

The fuel injection pump in a modern diesel engine simply creates pressure in the common line, and TDI piezo injectors (piezoelectric injectors) are capable of injecting a clearly defined amount of diesel fuel into the cylinders of a diesel engine in a very short period of time (less than 0.2 milliseconds) at the command of the ECU.

Also in some designs of diesel internal combustion engine power systems you can find so-called pump injectors. This means that each injection nozzle is equipped with its own high pressure pump. It turns out that the development of diesel technology today comes down to increasing injection pressure and maximum efficiency of the turbocharging system. This way it is possible to solve the main problems: increase power and reduce the level of exhaust gas toxicity.

TDI turbocharging: variable geometry turbine

Not only dynamics, but also efficiency and environmental friendliness largely depend on the efficiency of the TDI turbocharger. Correct air pressure must be realized over as wide a range as possible. For this reason, TDI engines are equipped with a turbocharger with variable turbine geometry.

The leading turbine manufacturers in the world use the following names:

VGT turbine (from the English Variable Geometry Turbocharger, which means variable geometry turbocharger). Produced by BorgWarner.
Turbocharger for diesel VNT (from the English Variable Nozzle Turbine, which means a turbine with a variable nozzle). This name is used by Garrett.

A variable geometry turbocharger differs from a conventional turbine in that it has the ability to adjust both the direction and magnitude of the exhaust gas flow. This feature allows you to achieve the most suitable turbine speed in relation to a specific operating mode of the internal combustion engine. In this case, the compressor performance increases greatly.

For example, the VNT turbine is based on special guide vanes. Additionally, there is a control mechanism, and the presence of a vacuum drive is also noted. These turbine blades rotate at the required angle around their axis, thereby being able to change the speed and direction of the exhaust flow. This occurs due to a change in the cross-sectional area of the channel.

The control mechanism is responsible for rotating the blades. Structurally, the mechanism has a ring and a lever. The lever is influenced by a vacuum drive, which controls the operation of the mechanism through a special rod. The vacuum drive is controlled by a separate valve that limits the boost pressure. The valve is an integral element of the electronic engine control system and is activated depending on the boost pressure. This value is measured by separate sensors:

a temperature sensor that measures the intake air temperature;
boost pressure sensor;

In other words, the turbocharging on the TDI works so that the charge air pressure is always optimal at different engine speeds. In fact, the turbine doses the energy of the exhaust gas flow.

As is known, at low engine speeds the exhaust flow rate (energy) is quite low. In this mode, the guide vanes are usually closed, thereby achieving a minimum cross-section in the channel. As a result of passing through such a channel, even a small amount of gases spins the turbine more efficiently, causing the compressor wheel to rotate noticeably faster. It turns out that the turbocharger provides greater performance at low speeds.
If the driver sharply presses the gas, then the effect of the so-called “turbo lag” occurs in a conventional turbine. Turbo lag should be understood as a delayed response to pressing the gas pedal, that is, not an immediate increase in power, but a pick-up after a short pause. This feature is due to the inertia of the turbocharging system, as a result of which the gas flow is insufficient at the moment of a sharp increase in crankshaft speed. In turbines with variable geometry, the guide vanes rotate with a certain delay, which allows you to maintain the required boost pressure and practically get rid of turbo lag.
When driving at high and close to maximum engine speeds, the exhaust gases have maximum energy. To prevent the creation of excess boost pressure, the blades in variable geometry turbines are rotated so that a powerful flow of gases moves through a wide channel with the largest cross section.

We also recommend reading the article about the service life of diesel turbines. From this article you will learn about the service life of this unit in comparison with gasoline analogues, and will also get the opportunity to familiarize yourself with the basic tips and recommendations for increasing the service life of a diesel engine turbine.

The relatively short service life of the turbocharger is due to the fact that only variable geometry turbines are installed on the TDI. During engine operation, the turbocharger spins up to 200 thousand rpm and constantly interacts with the flow of exhaust gases heated to 1000 degrees Celsius. Such thermal and mechanical loads, as well as the individual design features of these turbines, relatively quickly lead to the need to repair or replace the turbocharger.

Let's sum it up

Thanks to the developments and engineering solutions of Audi, the diesel engine managed to rise to a new stage in its evolution. The efficiency of TDI engines is a kind of record. The Audi 100 TDI covered 4,814.4 kilometers on just one full tank of fuel. The average speed was about 60 km/h, while the average fuel consumption was just over 1.7 liters per 100 km. Also, TDI engines closely compete with gasoline units not only on the streets, but also on race tracks. An excellent example is the diesel Audi R10 TDI, which regularly wins victories on the most difficult tracks.

Finally, we would like to add that the main guarantee of a long life for both a TDI engine and any other is the correct selection and timely replacement of engine oil, proper operation and driving on high-quality fuel, as well as professional service. Compliance with these conditions will allow the engine and other related systems to remain operational for hundreds of thousands of kilometers.

Which is better HDI, TDI, SDI, or CDI? What do these abbreviations stand for, and what is the difference between these engines?

It is no secret that diesel engines are more profitable than gasoline engines, but deciding on the type of fuel does not mean deciding on the type of diesel engine itself. A fairly common problem for many beginners is confusion between numerous abbreviations (HDI, TDI, SDI, CDI), on which a lot depends in the future.

It depends on the “character” of the car, its “susceptibility” to breakdowns, as well as the cost of repairing these breakdowns, as well as fuel consumption and much more. In this article, I will try to explain as clearly as possible what the differences are between different modifications of diesel engines, so that you can get your bearings and choose the most suitable option for yourself.

Looking ahead, I will say that the last two letters “.DI” of all the above abbreviations mean Direct Injection - direct injection. Direct injection technology, or as it is also called, is one of the most advanced today and provides for the presence of a common channel through which fuel is supplied.

HDI engine

The abbreviation HDI is assigned to motors that are based on technology Common Rail (developed by Bosch in 1993). The engine itself and HDI technology were developed by the world famous automobile concern PSA Peugeot Citroen. HDI, as I already said, belongs to the line of engines with direct injection, the characteristic differences are reduced fuel consumption by ~15%, reduced noise by ~10 dB, while simultaneously increasing power by as much as ~40%. Motors with the HDI prefix are considered more durable and “tenacious”.

TDI engine

The abbreviation TDI is perhaps the most popular and easiest to decipher. The first letter “T” in this abbreviation denotes the presence of turbocharging, which allows you to get a serious increase in power. A turbo engine has all the properties inherent in turbocharged engines; it is more economical, has cleaner exhaust, and is more expensive to maintain. In addition, few people know that most turbines installed on turbo engines are designed for ~150-200 thousand km. mileage, and this despite the fact that the engine itself, as a rule, is “millionaire”.

Current: How to check a diesel engine turbine? Diagnosing faults at home

SDI engine

SDI class motors are distinguished by their long life and simplicity of design. Long mileage is not a problem for SDI, the motors are very durable and reliable, but if repairs are still required, the cost is unlikely to please you.

CDI engine

The motor with the CDI nameplate is a Mercedes development, which is based on the same Common Rail technology as the above power units. Engines of the CDI line are more demanding in terms of fuel quality (often the fuel pump, injectors, etc. “compost the brains”), while they are very economical and dynamic on the road.

Well, that's all. I hope I clearly explained the difference between HDI, TDI, SDI, and CDI, now you can easily navigate and choose the engine that is suitable for your type and class. Thank you for your attention and see you again at Question Auto.

vopros-avto.ru

TDI (Turbocharged Direct Injection) engine: what is it?

The TDI diesel engine (the abbreviation stands for Turbocharged Direct Injection) is the brainchild of engineers from the Volkswagen automobile concern, work on which began in the 70s of the twentieth century. The name TDI itself is a trademark protected by a patent, to which the concern has exclusive rights, which means that the origin of the engine can be unmistakably determined by such an inscription.

Similar power units are installed on the entire subsidiary range of the German automobile giant, be it cars, trucks, jeeps, minibuses. Also, some models of companies with which Volkswagen has collaborated for some time have TDI engines. Let's take a closer look at what a TDI engine is? What are its advantages and is it reliable and promising?

Overall assessment of the benefits of TDI

Among the identified advantages of the Turbocharged Direct Injection power plant, one cannot help but pay attention to the following:

power;
efficiency;
compactness;
environmental friendliness.

This set was not determined immediately and not even after the appearance on the market in 1980 of the Audi 80 with a TDI under the hood, but only after numerous modifications and improvements, which led to the launch in 1989 of a new powerful turbodiesel, which in many ways is not inferior to gasoline units.

Experts recognize that TDI is one of the best modern diesel engines, the efficiency of which is determined based on the ratio of initial power and torque per unit of cylinder volume and fuel consumed.

The role of the variable geometry turbine

The main advantage of the engine, along with the direct injection system, is variable geometry turbocharging, which makes this type of engine competitive not only in related circles, but also in gasoline ones. In such a turbocharger, the direction and parameters of the exhaust gas flow can be adjusted, thanks to which it is possible to achieve the most suitable turbine rotation speed, and this has a very positive effect on performance. A conventional turbine does not provide such a possibility.

The VNT turbine, for example, is equipped with guide vanes, a vacuum drive and a control system. Moving around their own axis, the blades occupy a position at the desired angle, thus changing the cross-section of the channel. This allows you to adjust the speed and vector of the exhaust.

The rotation of the blades is controlled by a control mechanism equipped with a ring and a lever that receives the influence of a vacuum drive, regulated by a separate rod. In turn, the drive is controlled by a valve that is part of the engine ECU and responds to changes in boost pressure thanks to signals from the temperature sensor (at the intake) and the boost pressure sensor.

In general, a TDI turbine is a kind of exhaust flow energy dispenser that provides the required air pressure in any engine operating mode.

Read also: What is a TSI engine, its design, pros and cons.

Technological differences TDI

TDI is economical in fuel consumption and shows respectable efficiency. It is worth noting the high efficiency of the installation due to the increased injection pressure, reaching 2050 bar, and this despite the fact that analogue models show only 1350 bar. As is known, the injection pump is responsible for maintaining the total pressure in the line, and piezoelectric injectors, based on a signal from the electronic control unit, carry out strictly dosed injection, spending less than 0.2 ms.

A significant step towards increasing the efficiency of diesel engines was the introduction of the Common rail system (battery supply system), thanks to which the dependence of the injection mechanism on the crankshaft angle and engine operating mode is removed. This creates the conditions for fuel injection into the cylinder under high pressure when operating under light loads. Although the Common rail system is superior in maintainability to the conventional fuel supply system, its presence forces special requirements on fuel quality, in which it is somewhat inferior to the traditional system.

Among the atypical features of TDI engines are three points:

By combining the injector with the pump, it was possible to provide comprehensive control of the fuel injection mechanism, which increased torque and functional elasticity when changing operating conditions.
Fuel combustion is not accompanied by high shock loads, so the engine noise is low.
The concentration of nitrogen oxide in the exhaust is low, which explains the acceptable toxicity level, which remains a problem for other types of engines. This power unit is rightfully recognized as the most environmentally friendly among its peers.

TDI engine problems

According to specialized resources, the TDI reliability indicator is quite high and with properly organized maintenance it will withstand a million kilometers. The most modern compressors have also increased in reliability and sometimes “live” no less than the engine itself. However, on average, the service life of most turbines is limited to 150-200 thousand kilometers. This pattern is explained by the high temperature of the exhaust gases, reaching 1000℃, and the significant rotation speed, close to 200 thousand rpm.

Another vulnerability is the injectors, the service life of which is directly dependent on the quality of the fuel and the health of the power system.

To extend the life of TDI's weakest links, there are some important steps to keep in mind:

timely oil change;
timely replacement of the air filter;
regular diagnostics of boost pressure.

It remains to add that since Turbocharged Direct Injection engines are quite complex for self-service, the right solution would be to turn to the services of specialized services.

general analysis, pros and cons of the motor

The abbreviated name for the TDI diesel engine stands for Turbocharged Direct Injection. The creation of Volkswagen design engineers at the automobile concern.

The development of this engine began in the distant 70s. The concern has exclusive rights to the name TDI, since the name is protected by a patent, so it is always possible to determine the origin of such engines without errors.

The entire subsidiary range of cars of German origin is equipped with such power units, regardless of the type of vehicle, which includes minibuses, trucks, cars and jeeps.

Some other companies with which Volkswagen has signed a cooperation agreement also have the right to use TDI engines. To understand, it is necessary to characterize this power unit.

General analysis of TDI engines

The main characterizing advantages of such engines that you need to pay attention to are:

– environmental friendliness;

– efficiency;

– compactness;

– power.

All these positive characteristics did not appear immediately. Even after the introduction of the Audi 80 with TDI engine, such engine characteristics did not prevail. Only after painstaking work and various types of modifications in 1989, manufacturers released a powerful turbodiesel, which was absolutely not inferior to gasoline engines.

Experts confirm that TDI engines are the best in modern times. Their effectiveness is determined from the proportion of the initial power and torque per 1 cylinder volume and consumed fuel.

Variable geometry turbine functions

Along with the direct injection system, the main indisputable advantage of the engine is variable geometry turbocharging, which makes such engines competitive not only among diesel, but also gasoline engines.

In this turbocharger, the distribution and performance of the exhaust gas flow are subject to regulation. Due to this, it is possible to achieve the desired turbine rotation speed, which has a positive effect on productivity. A simple turbine does not have this capability.

If we consider the VNT turbine, its design includes guide vanes, a control system and a vacuum drive. When moving around their axis, the blades are in the position of the desired angle, and due to this, the cross-section of the channel changes. Based on this, it becomes possible to adjust the speed and vector of the exhaust.

The control mechanism always keeps the rotation of the blades under control. It is equipped with a ring and a lever that receives the influence of a vacuum drive controlled by an independent draft.

The valve is a drive control; it is part of the engine ECU and is responsible for changing the boost pressure using signals that come from the temperature sensor and the boost pressure sensor.

The exhaust flow energy dispenser is a kind of turbine on a TDI engine. The dispenser provides the necessary air pressure under any engine operating conditions.

TDI technical differences

The AUDI v12 shows respectable efficiency and economical fuel consumption. Due to the increased injection pressure, which reaches 2050 bar, the installation is highly efficient. When compared with other models, their performance does not exceed 1350 bar.

Everyone knows that the injection pump is responsible for maintaining the overall pressure in the line. Based on a signal from the electronic control unit, piezoelectric injectors produce dosed injection at a time cost of less than 0.2 ms.

The common rail battery supply system has provided a way to improve the efficiency of diesel engines. Thanks to which the injection mechanism becomes independent of the crankshaft rotation angle and the operating mode of the engine.

Under increased pressure when working with light loads, the prerequisites are created for fuel injection into the cylinder. Compared to a simple fuel supply system, the Common rail system is superior in maintainability. Its presence requires increased demands on the quality of fuel, in which a simple system loses.

Based on the number of atypical features of TDI engines, several points can be corrected:

Integrated control of the fuel injection device originated from the connection of the injector with the pump. Due to this, when modifying the operating mode, the torque increased.

There are no high shock loads during fuel combustion, this is due to the low noise level of the engine.

The concentration of nitrogen oxide in the exhaust is low. In this regard, the toxicity indicator is acceptable, which cannot be said about other types of engines. Among its peers, this unit is rightfully considered the most environmentally friendly.

TDI engine malfunctions

The reliability indicator of TDI engines is quite high, according to data from specialized resources. With proper, well-organized maintenance, it can be used for millions of kilometers.

The degree of reliability of modern compressors has also increased and sometimes reaches no less than the service life of the engine itself. 150-200 thousand kilometers is the average resource of most turbines.

This resource is achieved due to the high temperature of the exhaust gases, which can reach 1000 degrees, as well as the high rotation speed, which approaches two hundred thousand revolutions per minute.

The service life of the injectors directly depends on the serviceability of the power supply system and the quality of the fuel, which is a disadvantage.

The most significant measures that will extend the life of TDI's weak links are:

– timely oil change;

– periodic change of the air filter;

– systematic diagnosis of boost pressure.

Turbocharged Direct Injection engines are quite difficult to maintain independently, so it is always recommended to contact specialized car services.

Summarizing

The diesel engine managed to rise to a completely new level, thanks to the developments and solutions of engineers. A record was set for the efficiency of TDI engines. On the first full tank of fuel, the Audi 100 TDI model covered a mileage of 4814.4 kilometers

Average fuel consumption was 1.7 liters per 100 km, and the average speed was 60 km/h. TDI engines take the lead over gasoline engines not only in the city, but also in racing competitions. The diesel Audi R10 TDI regularly achieves victories, even on the most difficult tracks.

With an error-free selection and timely replacement of engine oil, with proper operation and, of course, using specialized service, the TDI engine will live a long, carefree life. Subject to the simplest measures and conditions, these motors will remain operational for many thousands of kilometers.

shokavto.ru

Features of the TDI engine in Volkswagen cars

The TDI engine offers increased power with low emissions.
The abbreviation TDI (Turbo Diesel Injection) refers to a diesel power unit that has increased torque, low fuel costs and high power. What other positive aspects and specific features does such a motor have?

The only Volkswagen model that comes with a TDI is the Toaureg all-wheel drive SUV. This type of engine is not the most popular in Volkswagen cars, unlike the TSI. Nowadays (2016) only TSI engines are installed on Passat B8, Passat CC, Tiguan. In addition to TSI, Golf and Jetta also have MPI engines.

Every modern engine with a turbocharger and direct injection in Volkswagen vehicles is labeled TDI. An important distinguishing feature for each such engine is that fuel injection, which is carried out under increased pressure along with variable turbine geometry, allows combustion to be carried out extremely efficiently.

When using direct fuel injection technology, an efficiency level of a maximum of 45 percent can be achieved. As a result, a significant portion of the possible fuel energy is converted into kinetic energy, that is, into motor power. Although this requires that the fuel burns almost completely and efficiently. This is achieved using a special configuration of the combustion chamber.

The main positive aspects of TDI

The TDI engine system is economical. Its most important positive aspects are:

low fuel consumption;
small volume of emissions of harmful substances;
the need to carry out auto service work and maintenance only occasionally.

Directly at low speeds, it is possible to significantly increase power up to the maximum rotational speed. There is an improvement in acceleration performance, and at the same time in the quality of operating dynamics. The increased torque also ensures maximum driving comfort when equipped with a TDI engine.

Direct or pilot fuel injection?

Direct fuel injection engines burn fairly harshly. As a result, during a cool start, a distinctive hum usually appears. To avoid this, diesel fuel is pre-injected.

Before the main cycle, a small amount of fuel is supplied directly into the combustion chamber. The pressure in the chamber does not increase immediately, but gradually, so combustion becomes “soft”.

Reducing harmful emissions

After the fuel is pre-injected, a post-injection process occurs, resulting in a reduction in the emission of harmful substances. Nitrogen oxides in the exhaust are minimized due to the fact that a little fuel enters the combustion chamber based on the speed. When the air that is absorbed and at the same time the exhaust gases are mixed, the temperature in the chamber decreases, so the volume of nitrogen oxides decreases.

Engine turbocharger

TDI engines use a turbocharger with variable geometry, which allows the air that is absorbed to be compressed. Due to this, the volume of absorbed air in the chamber increases. As a result, engine power increases at the same volume and at the same speed.

Two turbines form the turbocharger device. The turbine located in the exhaust tract begins to rotate from the outgoing mass of exhaust gases. It begins to move the compressor wheel, which compresses the air directly at the inlet. The air heated during compression is cooled and then enters the chamber. Since when the temperature decreases, the volume of air also decreases, there is more of it in the chamber.

Changing turbine geometry

The VTG system is now quite successfully used in TDI engines. At low speeds and low gas volume, the control unit changes the location of the mechanical propelling blades, at which the diameter narrows. This accelerates the gas flow and increases pressure. As the engine speed increases, the exhaust pressure increases, so the control unit, on the contrary, increases the pipeline diameter. Such superchargers help provide additional power to the engine, reducing emissions and increasing throttle response.

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What is a TDI engine

Many countries are experiencing rapid growth in the popularity of diesel engines. That’s why motorists are actively interested in the most optimal options among cars that have internal combustion engines running on diesel fuel under the hood.

The TDI family of engines is deservedly considered one of the best diesel engines. This is a development by Volkswagen, which equips a wide range of models of its cars and cars that are part of WAG with such engines. This includes cars from Audi, Volkswagen, Skoda, etc. Although it would be fair to call the Audi developers the authors of the project. But since they are part of a single group, this is not of fundamental importance.

Although work on TDI began in the 70s of the last century, it was only in the 21st century that these installations became truly complete, operational and highly efficient. Many people want to buy a car with such an engine. And there are a number of objective reasons for this.

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But before making a final decision, it is recommended to study in detail all the features of these engines, consider their technical aspects, and take into account their strengths and weaknesses.

A little history

Diesel engines have always been considered as internal combustion engines with rather poorly realized potential. This attracted the attention of a large number of automakers.

The engineers' task was to make the engine less noisy, slower and higher-speed, which would make it possible to install similar internal combustion engines on passenger car models. All efforts and hard work were ultimately crowned with success, and the world saw a powerful, economical and very environmentally friendly diesel power unit, the performance characteristics of which were practically not inferior to its gasoline counterpart.

The pioneer is Audi, which in the 80s produced and installed on the Audi 80 a naturally-aspirated diesel engine with a displacement of 1.6 liters and a power of 54 horsepower. As technology developed and improved, already in 1989 it was possible to establish mass assembly of compact, but at the same time powerful and high-torque turbodiesels, which received the world famous name TDI.

The very first TDI was presented in the form of a 2.5-liter 5-cylinder engine with an intercooler and turbocharging. All this made it possible to achieve a power of 120 horsepower with a torque of 256 Nm.

The launch of this engine on the market showed that there is great demand for it. TDI has become an excellent alternative to gasoline units and has managed to impose competition. TDI differed favorably from other diesel engines with excellent dynamics and low fuel consumption.

Features and Benefits

First of all, car enthusiasts are interested in what a TDI engine is and what the abbreviation used stands for. In fact, it is not difficult to understand what TDI means and what the essence of this engine is, if you look at the full name. The full transcript sounds like Turbocharged Direct Injection.

Such engines can be found not only among the WAG model range. There are a number of cars where the engine is a TDI engine. These are products of companies with which Volkswagen cooperates.

It is important to note that the TDI acronym itself is a proprietary trademark. WAG has exclusive rights to it. This allows you to buy a car without any fear and be sure that the engine belongs to WAG.

When Audi became part of WAG, the Volkswagen automaker very quickly became a leader among the best manufacturers of diesel power plants. The innovative solutions and new technologies used have made it possible to obtain a huge list of advantages and privileges. At the same time, the main advantages of TDI turbodiesels are:

slight noise during operation;
excellent torque performance;
low consumption;
low level of toxicity of emitted exhaust.

Although TDI diesel engines offer significant advantages over their competitors, the most significant are their excellent efficiency and economy. These two factors predetermined the success of the project.

Similar characteristics were largely achieved due to higher injection pressure. If we compare it with analogues in which this indicator is at the level of 1350 bar and no higher, then TDI produces 2050 bar.

The engine uses a system in which the injector is combined with a fuel pump. This allows you to control all fuel injection processes. This innovation made it possible to achieve high torque levels with simultaneous smooth operation in different modes.

A special fuel supply system ensures uniform and gentle combustion of fuel, thereby reducing shock loads to a minimum. This has already led to another advantage in the form of quiet operation and reduced exhaust gas emissions.

An important step to improve the efficiency of diesel engines was the introduction of a battery supply system, that is, Common Rail. With its help, it was possible to get rid of the dependence of the injection mechanism on the current angle of rotation of the crankshaft and the operating mode of the engine. This created the conditions for fuel injection into the working cylinders under high pressure even when the engine was operating at minimal load.

Despite the fact that the battery fuel supply system is not inferior to traditional systems in terms of maintainability, and in some places surpasses it, it is extremely important to use the highest quality fuel. That is, it is better to refuel TDI at proven gas stations.

We can highlight several technological features of these engines that set them apart from their competitors and allow us to talk about some unique, non-standard or atypical solutions.

Since the injector is combined with a fuel pump, the system allows comprehensive control of the fuel injection mechanism. As a result, this led to an increase in torque, smoothness and elasticity of movement, regardless of the current operating mode of the engine.
When diesel combustion occurs in the engine, it is not accompanied by serious shock loads, which occurs on many analogues. This makes it possible to ensure a low noise level during the operation of the power unit.
TDIs are characterized by a very low concentration of nitrogen oxide in the exhaust produced. This explains the fairly adequate level of toxicity, which many other diesel engines cannot achieve. Among its competitors, it is the TDI that is deservedly and rightly considered the most environmentally friendly.

Such features bring the engine to a leading position. This is a very popular motor on the market, which largely justifies its cost.

For the price, this is not the most affordable diesel engine. Therefore, the cost factor sometimes scares away potential buyers. To make sure that your choice is fair and correct, you should further study the motor and be sure to become familiar with its potential malfunctions.

To sum it up, TDI can rightly be called powerful, silent, environmentally friendly engines that minimally pollute the environment. It is not surprising that in Europe there is an increased demand for cars equipped with such engines.

Reliability factor

The fact that we are talking about a turbocharged diesel power unit makes some car enthusiasts doubt the reliability of these engines. Allegedly, due to the turbine, the durability and service life of the unit are significantly reduced.

But in reality everything is somewhat different. It is thanks to the turbocharging system that TDI engines have excellent power performance with a small displacement. This also entailed a noticeable increase in efficiency.

The diesel engines under consideration can rightly be called reliable. Everything directly depends on the specific operating conditions and directly on the car owner’s attitude towards his vehicle.

For engine reliability to really fail, you need to regularly refuel the car at cheap gas stations, where diesel fuel is only price and name. That is, it is the quality of diesel fuel that most strongly influences the performance and serviceability of TDI.

If the motorist chooses good gas stations, fills with proven and high-quality fuel, and also follows standard instructions for timely maintenance, which must be done with absolutely any engine, then in certain cases the viability of the TDI can reach 1 million kilometers. Moreover, these are not fantasies or indicators under absolutely ideal conditions.

To ensure that TDI does not fail, and the car owner can always count on the performance and reliability of his turbodiesel, it is enough to know the 3 main weak points of the engine:

low quality fuel;
fuel injectors;
turbocharger.

We figured out the quality of diesel fuel. Everything here is simple and obvious. Fill with good fuel and there will be minimal problems.

As for such a weak point as injectors, their performance and life cycle are most directly related to the first point, that is, to the quality of the fuel. If you fill in decent diesel fuel and maintain the fuel system in good general condition, the injectors can last a long time and reliably. If necessary, they can be changed. The procedure is not the most complicated and not particularly expensive if the car owner decides to seek help from a car service center.

Of particular note is the turbine, or turbocharger, used on the TDI to improve power, performance and efficiency. The turbine is always the weak point on any engine with a turbocharger, since its resource is noticeably less than the resource of the engine itself.

Practice shows that on average a TDI turbine can faithfully last from 120 to 160 thousand kilometers. Then replacement is required.

Considering the rate of turbocharger wear on many TDI competitor engines, the WAG design has a very respectable performance record. This resource looks quite acceptable and long-lasting for a turbo engine.

It is important to understand one more point here. The development of engines and machines is now carried out in such a way that manufacturers do not expect operation for 15-20 years. In Europe and the USA, it is customary to replace cars after 3-8 years, since they gradually exhaust their service life, environmental performance deteriorates, etc. In our country, even 10-15 years of operation is considered the norm.

The same Europeans are not particularly concerned that the turbine resource is 160 thousand kilometers. When this mileage is reached, the car is scrapped or sold abroad. Having bought such a car and changed the turbocharger, you can safely drive it for at least another 100-120 thousand kilometers.

Already understanding what TDI means and what the letters in this abbreviation stand for, it would be a good idea to take a closer look at the technical aspects of these turbodiesels. And then you can decide for yourself whether it is worth buying cars with engines under the hood designated TDI.

Fuel injection system

When diesel engines were in the earliest stages of their development, the joint operation of the fuel pump (fuel injection pump) and mechanical injectors made it possible to achieve a pressure of no more than 40 bar.

If you take a modern diesel engine, it is capable of delivering 1600 bar and even higher. This trend of pressure growth is explained by the fact that very little time is given for mixture formation in diesel engines.

When the crankshaft rotates at a speed of about 2 thousand revolutions per minute, it takes literally a few milliseconds to create a mixture of diesel fuel and air. The higher the shaft rotation speed, the shorter this time period.

To create a homogeneous and high-quality mixture, high pressure is required. If the pressure is low, the mixture is of poor quality and does not burn completely, which reduces efficiency and increases exhaust toxicity.

In old diesel engines, the fuel injection pump, working in tandem with mechanical injectors, was the unit responsible for pressure. Modern diesel engines are equipped with a special system called Common Rail.

If the injection pump can simply create pressure in the line, then the piezoelectric injectors in the TDI system can supply (inject) a strictly defined volume of fuel into the cylinders in an extremely short period of time. The injection time and formation of the air-fuel mixture takes literally 0.2 milliseconds or even less. The corresponding commands are sent through the control unit.

In fact, the whole essence of the development of diesel engine technology is directly related to increasing fuel injection pressure and increasing the efficiency of the turbocharger.

Turbocharging system in TDI

In order for the turbo to operate as efficiently and correctly as possible, a wide range of operation is required. This is why the TDI uses a variable turbine geometry system.

Compared to a conventional turbine, the variable geometry design allows you to adjust the direction and magnitude of the exhaust gas flow. This feature contributes to a noticeable increase in turbine speed depending on the specific operating mode of the engine. The turbocharger thus receives increased performance.

That is, the TDI implements the principle according to which optimal pressure is always created in the engine at all modes and engine speeds. With the help of a supercharger, it is actually possible to dose the energy of the exhaust gas flow.

Here it is worth highlighting several nuances that largely explain the advantages of the turbocharging system in TDI engines.

When the engine is running at low speed, the exhaust flow rate is also low. While in this mode, the turbine guide vanes are often closed, which allows for the creation of a maximum small cross-section in the channel. When a small volume of gas passes through such a channel, it is able to effectively spin the turbine and stimulate the compressor wheel to rotate faster. So it turns out that at low speeds the performance of the turbocharger still remains high.
When you sharply press the gas pedal, a gap appears in a conventional turbine, which is called a turbo lag. That is, the engine’s response to the pressed accelerator pedal is delayed, and the increase in power does not occur instantly, but with a pause. This is explained by the fact that the turbocharging is inertial, and the available gas flow is not enough when the crankshaft speed increases sharply. But because the TDI uses a variable geometry turbine, the guide vanes rotate with some delay. This makes it possible to maintain high boost pressure. This actually prevents the motor from stalling. The effect of turbo lag is almost irrelevant for TDI.
When driving at high and maximum speeds, the exhaust gas has maximum energy. To prevent excessive turbocharging pressure, the blades rotate in a certain way. Thus, a large and powerful gas flow follows a wide channel with a large cross-section.

TDI has a relatively short turbine life. But there is a logical explanation for this. A turbine with variable geometry is used here. Therefore, during operation, the compressor rotates at a speed of up to 200 thousand revolutions per minute, in parallel interacting with air flows from the exhaust, the temperature of which can reach 1000 degrees Celsius.

It is these mechanical and thermal loads, as well as some design features of the TDI, that lead to wear. As a result, repair or complete replacement of a worn turbocharger is required.

How to avoid malfunctions

If you plan to operate a car equipped with a TDI engine for more than 5 years from the date of its release, then you will not be able to prevent wear and tear on the turbocharger even if you really want to. The system has its own resource, which is limited to a maximum of 200 thousand kilometers. When the mileage exceeds this value, the compressor will have to be replaced.

But for a modern car, a resource of 200 thousand is already not bad. After all, here we are talking only about a turbocharger, while a turbodiesel itself can easily last about 1 million kilometers.

By knowing the weak points of TDI, which are the injectors, turbine and dependence on the quality of diesel fuel, serious malfunctions can be prevented. To do this you need to follow a few simple rules.

Change your oil on time. Use engine oil only in accordance with the vehicle manufacturer's requirements and refill it at the specified intervals. Taking into account the weather and road conditions of our country, it is worth subtracting at least 20% from the replacement period recommended in the operating manual, and changing the oil a little more often. This will allow you to maintain the performance of the turbo engine, efficiently lubricate and cool the internal parts and rubbing surfaces. This extends service life and minimizes potential malfunctions.
Be sure to change the air filter. The operation of the turbine and the entire engine is greatly influenced by the quality of air purification. To prevent large amounts of debris from accumulating, try to periodically check the condition of the air filter. If it is heavily clogged, it is not recommended to try to clean it. The best solution would be replacement. In addition, the consumable is far from the most expensive, and such a replacement will not entail large expenses.
Check the boost pressure. This can be done during scheduled maintenance, as well as when replacing consumables during a visit to a car service center. Although for some it will not be difficult to check the pressure in the turbocharging system with their own hands. Such diagnostics will allow you to timely identify possible problems with the turbine, perform some repair work and extend the life of the compressor. If the turbine is almost worn out and its service life is coming to an end, it will have to be replaced completely. The pleasure is not the cheapest, but the TDI will be able to serve for at least several more years without any serious and expensive malfunctions.
Refuel at proven gas stations with high-quality diesel fuel. The recommendation may seem banal and obvious, but it is this rule that is most often ignored by domestic owners of cars with TDI turbo engines. But fuel is the main cause of all the problems and malfunctions associated with an objectively excellent diesel engine. By not sparing money on more expensive, clean and safe diesel fuel, you will save significantly on the repair and maintenance of your TDI.

For all its advantages, the TDI design does not allow you to carry out a number of repairs on your own. It is not recommended to take risks and interfere with the design of a turbodiesel without the appropriate skills, experience and knowledge. It is better to get serviced at specialized car services, where they are perfectly familiar with all the nuances of TDI and will be able to carry out high-quality diagnostics and repair work.

TDI engines have become a real breakthrough in the world of diesel power plants. Moreover, the developers do not stop at the success achieved. They hold landmark records in terms of efficiency and environmental friendliness. Although such engines slightly increase the starting cost of the car, they are an excellent alternative not only to conventional diesel engines, but also to modern gasoline engines. Therefore, sometimes it is better to pay more, but get a motor with the abbreviation TDI under the hood.

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TDI engines - what are they? Features, characteristics

Until recently, diesel engines were used only in commercial vehicles. Such engines in passenger cars are a real curiosity for Russian car enthusiasts. Previously, foreign manufacturers (including VAG) did not officially supply such engines to the domestic market. But now cars and crossovers from Volkswagen with a TDI engine have begun to appear. What it is? Let's look at it in our article.

Characteristic

First, we note that engines with this abbreviation are found not only on Volkswagens.

Audi also has these units. TDI engines are engines with turbocharged diesel injection (hence the abbreviation). These units are also distinguished by the direct supply of Common Rail fuel.

Peculiarities

The main feature is the turbine that is equipped with the TDI engine. What it is? This is a mechanism that provides forced air supply, thereby increasing the torque and power of the motor. But unlike other engines, the 2.0 TDI has a special turbine design - with variable geometry. How is it different from conventional compressors? This design allows you to regulate the magnitude and direction of the exhaust gas flow. This gives a significant increase in power and high fuel efficiency. So, from two liters of volume you can get up to 170 horsepower. And thanks to the direct injection system, fuel consumption is about 5.5 liters in the combined cycle.

Some TDI engines in Volkswagen are equipped with a VNT turbine.

This abbreviation means that it is a compressor with a variable nozzle. The supplier of such turbines for Volkswagen is Garrett. The design of this unit assumes the presence of:

Vacuum drive.
Control mechanism.
Guide vanes.

The latter are designed to change the speed of exhaust gas flow. This occurs by adjusting the cross-sectional area of the channel. Thus, the blades can rotate around their axis at a certain angle. This action is performed using a control mechanism. It consists of a lever and a ring. The mechanism is activated by a vacuum drive. It is he who acts on the lever through a special rod. The vacuum drive is equipped with a boost pressure limiting valve. It is connected to the electronic engine management system. The mechanism is activated by the boost pressure and intake air temperature.

TDI and Audi TT

The TT is one of the most popular coupes from Audi. Previously, the car was equipped only with gasoline power plants. Diesel units were previously considered “vegetable” and had low traction. In addition, such a sports coupe simply needed a high-speed engine. But after using the TDI engine on the Audi TT, all stereotypes were dispelled.

This diesel engine had simply incredible performance. With a two-liter displacement, it developed 170 horsepower and as much as 350 Nm of torque. This gave a significant increase in dynamics. The car accelerated to hundreds in 7 and a half seconds. And the maximum speed was 226 kilometers per hour. And now the most important point is fuel consumption. And this unit consumed only 5.3 liters per hundred in mixed mode. You won't believe it, but this is real passport data from the manufacturer.

Ecologically pure

The TDI line of engines has held a leading position on the market for 20 years. One of them featured Clean Diesel technology. It provides deep cleaning of exhaust gases by converting nitrogen oxides into water vapor. The system has already been implemented in practice and has been successfully used in the USA since 2014. The 3.0 TDI engine meets all standards for the content of harmful substances in the exhaust. CO emissions per kilometer are only 130 grams.

What are the advantages of the TDI engine?

We have already found out what it is. Now let's look at the main advantages of these turbocharged units. In general, after Audi joined the VAG concern, the latter took a leading position in the list of diesel engine manufacturers. Thanks to innovative engineering solutions, their engines are distinguished by:

High fuel efficiency.
Low noise level (almost inaudible at idle).
High dynamics and torque.

Also, these power plants meet modern environmental requirements (Euro 6 exhaust standard). A significant increase in power was achieved thanks to the special design of the turbine. Unlike other engines, compressors from VAG units are capable of operating at a pressure of 2 thousand bar.

Modern analogues produce only 1300 Bar. Also in TDI engines the injector is combined with a pump. This allows for maximum control over fuel injection.

Conclusion

So, we found out what features the TDI engine has, what it is and what its advantages are. At the moment, TDI engines are among the most powerful, quiet and environmentally friendly. It is not surprising that they occupy a leading position in the global market.

Today, efficiency is the most important point that influences the purchase of a car. Efficiency means lower fuel consumption and longer service life of the power unit.

When solving this issue, the struggle between diesel and gasoline comes to the fore. There are a sufficient number of pros and cons of both one type of engine and the other. At the same time, we can say that diesel engines can reduce fuel consumption by 25-50%, and their lifespan is longer compared to gasoline options.

Diesel or gasoline?

Of course, it should be noted that the popularity of diesel units in Russia is somewhat less than in Europe. Although there are fans, and their number continues to increase. European demand is quite high and therefore automakers are constantly improving diesel engines. The desire to improve the performance of power units has led to the appearance of diesel engines on the market, which have some differences in design. Among them, diesel engines are best known under the abbreviations HDI, TDI, SDI. Therefore, we will try to answer the question: what is the difference between HDI, TDI, SDI diesel engines?

As for markings, the DI symbols indicate the use of a system that is based on a combustion chamber. The operating principle is based on the fact that the injectors have a common channel into which fuel enters under high pressure. The designations HDI and SDI imply the absence of , that is, these diesel engines are called atmospheric. In turn, power units labeled TDI are distinguished by the presence of turbocharging, which significantly increases engine efficiency.

HDI engine

Diesel engines with the abbreviation HDI are the development of such an automotive giant as PSA Peugeot Citroen. These power units use the Common Rail system. This system, which is determined by direct fuel injection into the combustion chamber, has reduced fuel consumption by 15%, increased power by 40%, and reduced noise by 10 dB. HDI motors have a longer service life. Thus, diagnostics at service stations are provided at the rate of once per 30 thousand km. It is also worth noting that the timing belt and accessory belts remain functional for the entire period of engine operation.

TDI engine

As already mentioned, TDI engines use turbocharging, which allows for increased power. At the same time, efficiency is at a high level, and exhaust purity meets standards. These engines were first used by the Volkswagen concern. They are easy to use and reliable. Although it must be said that there is such a drawback as the short life of the turbine, which is designed for 150 thousand km. True, the engine itself has a service life of one million kilometers.

SDI engine

If the prospect of expensive repairs does not appeal, then in this case it is worth paying attention to SDI engines. The power units of this modification are resistant to long mileage, and they are also highly reliable, which is due to the simplicity of their design.

Currently, TDI, HDI, SDI technologies are based on the third generation Common Rail system. The third generation is different in that they began to use piezoelectric injectors, which allow for more precise injection, and the fuel supply pressure was increased. In principle, engines with these markings have a minimum of differences, and their symbolism determines the manufacturer of the power units. Therefore, it is difficult to single out a winner in these three categories. The only conclusion is that the choice of diesel is justified and promising.

Used only on commercial vehicles. Such engines in passenger cars are a real curiosity for Russian car enthusiasts. Previously, foreign manufacturers (including VAG) did not officially supply such engines to the domestic market. But now cars and crossovers from Volkswagen with a TDI engine have begun to appear. What it is? Let's look at it in our article.

Characteristic

First, we note that engines with this abbreviation are found not only on Volkswagens.

Audi also has these units. TDI engines are engines with turbocharged diesel injection (hence the abbreviation). These units are also distinguished by the direct supply of Common Rail fuel.

Peculiarities

The main feature is the turbine that is equipped with the TDI engine. a mechanism that provides forced air supply, thereby increasing torque and power of the motor. But unlike other engines, the 2.0 TDI has a special turbine design - with variable geometry. How is it different from conventional compressors? This design allows you to regulate the magnitude and direction of the exhaust gas flow. This gives a significant increase in power and high fuel efficiency. So, from two liters of volume you can get up to 170 horsepower. And thanks to the direct injection system, fuel consumption is about 5.5 liters in the combined cycle.

Some TDI engines in Volkswagen are equipped with a VNT turbine.

This abbreviation means that it is a compressor with a variable nozzle. The supplier of such turbines for Volkswagen is Garrett. The design of this unit assumes the presence of:

Vacuum drive.
Control mechanism.
Guide vanes.

TDI and Audi TT

Ecologically pure

What are the advantages of the TDI engine?

High fuel efficiency.
Low noise level (almost inaudible at idle).
High dynamics and torque.

Also, these power plants meet modern environmental requirements (Euro 6 exhaust standard). A significant increase in power was achieved thanks to the special design of the turbine. Unlike other engines, those from VAG are capable of operating at a pressure of 2 thousand bar.

Modern analogues produce only 1300 Bar. Also in TDI engines the injector is combined with a pump. This allows for maximum control over fuel injection.

Conclusion

MultiJet is the general name for the second generation of turbodiesel engines equipped with a common-rail direct fuel injection system. What are this generation of engines, one of which was recognized as “Engine of the Year” in Europe?

But a little history. In 1986, Fiat introduced the Croma JDi, one of the world's first passenger cars equipped with a direct injection diesel engine. It was a landmark event in the world of automotive engineering. After all, such a power unit, despite its advantages (performance, efficiency, high torque), for a long time was absolutely not associated with a “passenger car”. Due to strong vibrations and noise, these motors were installed exclusively on commercial and military vehicles.

The fight against noise and vibration of a diesel engine could be carried out in two directions. The first is a simple and obvious way: to isolate the engine compartment from the car interior with soundproofing materials and install the engine on special supports that would absorb vibration.

The second path was much more labor-intensive and time-consuming. It was necessary to change the operating process in the engine and improve the design of the direct fuel injection system. But it was precisely this difficult direction for moving forward that the Fiat engineering team chose. It took more than three years to improve the Fiat Croma diesel engine alone. And this takes into account the active participation in the development of the project by specialists from Magneti Marelli and Elasis.

At the next stage, specialists from Bosch, one of the leading companies in the field of diesel engine fuel supply systems, joined the work. It took four whole years to prepare for production, and only in 1994 did diesel engines with direct fuel injection of the UniJet system begin to be installed on cars of companies belonging to the Fiat Group.

Later it became clear that, despite their outstanding characteristics, Unijet diesel engines are just an intermediate stage in a much more ambitious program of the Italian automaker. Fiat understood that without a radical improvement in consumer qualities - increasing power and dynamic characteristics, reducing fuel consumption and exhaust toxicity - Unijet diesel engines would become hopelessly obsolete within 7-8 years. Therefore, they were looking for a new original idea - this was the development of a revolutionary Common-Rail battery-type fuel delivery system, which was introduced in 1997. And only the world's first gasoline engine with direct fuel injection, proposed in the same year by Mitsubishi, prevented the development of the Fiat Group from becoming the best innovation in the automotive industry.

Yet Fiat's equally remarkable innovation has not gone unused. The first Common-Rail engine with low noise and vibration levels (the level was comparable to gasoline engines), with a large power reserve, was installed on the Alfa Romeo 156JTD. The new engines were significantly superior in many respects to diesel engines equipped with a preliminary combustion chamber, so soon Common-Rail engines began to be installed on all Fiat models. Dynamics improved by 12% while fuel consumption decreased by up to 15%. These were excellent results!

Despite this, the JTD engine was not flawless from a technical point of view. The two-valve gas distribution system used in it did not allow all the advantages of Common-Rail technology to be revealed. After all, the electronic injection control of the Common-Rail system allows you to repeatedly split the fuel injection phase. But in the JTD diesel engine there were only two such phases. During the first “pilot” injection of a small amount of fuel, the combustion chamber was heated and prepared to receive the bulk of the fuel. But greater fragmentation of the injection phase would make it possible to increase the softness and purity of fuel combustion, and, as a result, improve the power, economic and environmental performance of the engine.

In 2002, after 5 years of painstaking work, at the Paris Motor Show, the Fiat engineering group presented a 16-valve 1.9JTD diesel engine with a Multijet direct fuel injection system based on the Common-Rail principle.

The Multijet system also uses electronic control of the fuel injectors, but the software allows the overall injection to be divided into a large number of parts. This results in quieter combustion, reduced emissions and improved performance. In this case, the number of injection stages is determined by the results of monitoring the temperature and pressure inside the combustion chamber and the engine operating mode (cold start, intensive acceleration, etc.).

The next stage in the development of Multijet was the 1.3Mjet power unit, which in 2005 received the title of “International Engine of the Year” in the category of engines with volumes from 1.0l to 1.4l. The main advantage of this diesel engine is its extremely compact size. Fiat designers managed to fit 1248 cm3 of working volume into dimensions of 46x50x65 cm, despite the fact that the engine is equipped with exhaust gas recirculation and turbocharging systems with intermediate air cooling. At the same time, it was possible to further reduce the level of noise and vibration, significantly reduce fuel consumption and the level of emissions of harmful substances.

But stopping there is not Fiat's habit. Recent improvements to the turbocharging system (in particular the introduction of a variable geometry turbocharger) and exhaust gas recirculation system made it possible to introduce an even more progressive and innovative Multijet II fuel system in 2009.

The significant experience and high technical level of the Fiat Group in the development of fuel return systems allows the Italian concern today to offer cars that are equipped with economical and high-performance diesel engines that are in demand today!

This article is about a representative of the family of legendary JTD (Jet Turbo Diesel) engines, developed by FIAT in the mid-90s of the last century. These engines use a common-rail fuel system, which gave a new round of development to diesel engines and is today the main system used in diesel engines of passenger cars.
The engine of this 1.9 JTD family was installed in the world's first passenger car with a common rail fuel system, Alfa Romeo 156 in 1997. The use of the common rail system gave many advantages compared to classic diesel engines. Thanks to it, fuel consumption decreased by 15%, engine power increased by almost 40%, diesel torque increased, noise levels during engine operation decreased, and environmental performance reached the highest level, previously unattainable for diesel engines.
Over the years, various modifications of JTD engines have been installed on many brands of European-made cars and others.

1.3 liter engine:
Alfa Romeo MiTo, Chevrolet Aveo (2012), Fiat Albea, Fiat 500, Fiat Doblò, Fiat Grande Punto, Fiat Idea, Fiat Linea, Fiat Panda, Fiat Punto, Fiat Palio, Fiat Fiorino, Fiat Qubo, Fiat Strada, Ford Ka ( 2008), Lancia Musa. Lancia Ypsilon , Maruti Suzuki SX4 Diesel , Suzuki Ertiga , Opel Agila , Opel Astra , Opel Combo , Opel Corsa , Opel Meriva , Opel Tigra TwinTop , Suzuki Ignis , Suzuki Splash/Maruti Suzuki Ritz , Suzuki Swift/Maruti Swift/Maruti Swift Dzire , Suzuki Wagon R+, TATA Indica Vista, Indigo Manza

1.6 liter engine:
Alfa Romeo Mito, Alfa Romeo Giulietta (2010), Fiat Bravo, Fiat Doblò, Fiat Grande Punto, Fiat Idea, Lancia Delta, Lancia Musa, Opel Combo D, Suzuki SX4 (since 2013).

1.9 liter engine:
Alfa Romeo 145, Alfa Romeo 146, Alfa Romeo 147, Alfa Romeo 156, Alfa Romeo 159, Alfa Romeo GT, Cadillac BLS, DR5, Fiat Bravo, Fiat Croma II, Fiat Doblò, Fiat Grande Punto, Fiat Marea, Fiat Multipla, Fiat Punto, Fiat Sedici, Fiat Stilo, Fiat Strada, Lancia Delta, Lancia Lybra, Lancia Musa, Opel Astra, Opel Signum, Opel Vectra C, Opel Zafira, Saab 9-3, Saab 9-5, Suzuki SX4, Alenia Aeronautica Sky- Y

1.9 Twin Turbo
Cadillac BLS, Lancia Delta, Saab 9-3

2.0 liter engine:
Alfa Romeo Giulietta (2010) , Alfa Romeo 159 , Fiat Bravo , Fiat Doblò II , Fiat Sedici , Fiat Croma II , Lancia Delta , Opel/Vauxhall Astra , Opel/Vauxhall Insignia (single and twin turbo) , Chevrolet Malibu , Saab 9- 5 (single and twin turbo), Suzuki SX4

Engine volume 2.0/2.2 (PSA)
Fiat Scudo, Fiat Ulysse, Lancia Phedra

2.3 liter engine:
Fiat Ducato

2.4 liter engine:
Alfa Romeo 156, Alfa Romeo Spider, Alfa Romeo Brera, Alfa Romeo 159, Alfa Romeo 166, Fiat Croma II, Fiat Marea, Lancia Kappa, Lancia Lybra, Lancia Thesis

Engines with a volume of 2.3/3.0 liters:
Fiat Ducato. Iveco Massif

Let's return to our 2.3 Multijet engine (2287 cc). This motor was developed by Iveco and has two versions 120 MultiJet (SOFIM F1AE048ID) and 130 MultiJet (SOFIM F1AE048IN 2287), these engines have a power of 116 PS (85 kW) and 127 PS (93 kW) respectively. This engine is installed on Fiat Ducato vans and minibuses.

Let's take a closer look at the 120 MultiJet engine that was installed on the Fiat Ducato produced in 2008-2011, assembled in Russia at the plant Sollers in Yelabuga. This engine is an in-line four-cylinder sixteen-valve engine with a turbocharger and a second-generation “multijet” common rail direct fuel injection system. This engine is equipped with an electronic fuel injection control system with a Bosch EDC16c39 controller.

1. Injectors
2. Engine control unit
3. Fuel pump
4. Fuel filter
5. High pressure pump
6. Fuel pressure regulator
7. Fuel pressure sensor

The “multijet” system differs from the first versions of common rail in a more progressive fuel injection algorithm; it allows the injection phase to be split not into two, but into several stages, up to five inclusive, depending on the operating conditions of the engine. This made it possible to increase engine power by up to 25% and achieve vibration and noise levels comparable to gasoline engines. Also, the multijet system is less sensitive to fuel quality due to more complete and efficient fuel combustion with multiphase injection and has higher reliability compared to the classic pump injector system.
Maintenance of the 2.3 JTD engine and its fuel system is dictated by the characteristics of these engines. Common rail fuel equipment requires a high degree of fuel purification; if solid particles get into the plungers of the high-pressure pump, the pump fails, and the price of a new pump is not comparable to the price of high-quality fuel filter cartridges. Since the engine has a turbocharger, a clogged air filter can lead to turbo failure and ultimately lead to serious, expensive engine repairs. In light of the above, we recommend replacing the fuel filter cartridge and air filter at every engine oil change; when replacing the fuel filter cartridge, be sure to rinse and blow out the filter housing.
In general, these motors are quite reliable and have good performance. With proper timely maintenance, the 2.3 JTD engine will delight the car owner for a long time with good pickup, torque and smooth operation. It is not for nothing that this Engine has won a strong place in the engine compartment of a commercial vehicle.

Among the identified advantages of the Turbocharged Direct Injection power plant, one cannot help but pay attention to the following:

power;
efficiency;
compactness;
environmental friendliness.

The role of the variable geometry turbine

In general, a TDI turbine is a kind of exhaust flow energy dispenser that provides the required air pressure in any engine operating mode.

Technological differences TDI

Among the atypical features of TDI engines are three points:

By combining the injector with the pump, it was possible to provide comprehensive control of the fuel injection mechanism, which increased torque and functional elasticity when changing operating conditions.
Fuel combustion is not accompanied by high shock loads, so the engine noise is low.
The concentration of nitrogen oxide in the exhaust is low, which explains the acceptable toxicity level, which remains a problem for other types of engines. This power unit is rightfully recognized as the most environmentally friendly among its peers.

TDI engine problems

Another vulnerability is the injectors, the service life of which is directly dependent on the quality of the fuel and the health of the power system.

To extend the life of TDI's weakest links, there are some important steps to keep in mind:

timely oil change;
timely replacement of the air filter;
regular diagnostics of boost pressure.

It remains to add that since Turbocharged Direct Injection engines are quite complex for self-service, the right solution would be to turn to the services of specialized services.

Today, efficiency can be called one of the most important and decisive factors of all that influence the purchase of a car. This concept includes more economical fuel consumption and a longer service life of the unit itself. And as always, when solving this issue, the struggle between diesel and gasoline comes to the fore. At the same time, it can be noted that both the first and second types of engines have a sufficient number of pros and cons. At the same time, it can be noted that it is the diesel engine that makes it possible to reduce fuel consumption by 25-50%, and their lifespan is longer than the lifespan of gasoline units.

So which is better, diesel or gasoline?

First of all, it is worth noting that the popularity of diesel units in Russia is much less than their popularity in Europe. Although there are definitely fans of such engines, and their number is constantly growing. The demand for diesel in Europe is quite large and for this reason, European automobile concerns are constantly improving engines of this type. This desire for improvement is the reason why diesel engines began to appear on the market, which have some differences in design. The most famous among them are models with the abbreviations HDI, TDI, SDI. Therefore, in this article we will try to figure out how exactly these models differ from each other?

If we talk about markings, the letters DI indicate that this model uses a system whose operation is based on direct fuel injection into the combustion chamber. The operating principle of such a system is based on the fact that the injectors have a common channel into which fuel flows under sufficiently high pressure. The abbreviations HDI and SDI indicate the absence of turbocharging, that is, these diesel engines can be called atmospheric devices. In turn, models labeled TDI are distinguished by the presence of turbocharging, which significantly affects the increase in engine efficiency.

HDI diesel engine

Diesel engines, which are designated by this abbreviation, are the development of one of the automotive giants, the PSA Peugeot Citroen concern. These power units use the Common Rail system in their operation. This system, which is characterized by direct fuel injection into the combustion chamber, made it possible to reduce fuel consumption by 15%, increase power by 40%, and also reduce noise levels by 10 dB. HDI diesel engines have a longer service life. Thus, it can be noted that diagnostics at a service station can be carried out based on the calculation of once every 30 thousand km. In addition, it can be noted that the timing belt, as well as the belts of attached units, do not cease to function throughout the entire service life of the engine.

TDI diesel engine

As mentioned earlier, the TDI diesel engine uses turbocharging in its operation, which provides the ability to increase power. At the same time, efficiency indicators remain at a high level, and exhaust purity always fully complies with standards. For the first time, the Volkswagen concern began to use such engine models. Models of this type are reliable and unpretentious in operation. The only drawback of TDI diesel engines is the short turbine life, which is designed for 150 thousand km. But the engine itself has a resource of one million kilometers.

SDI engine

Those who are not tempted by the prospect of expensive repairs can be recommended to pay attention to SDI model engines. This modification of power units is characterized by high mileage resistance, as well as reliability, which is ensured by the simplicity of the design.

Today, it can be noted that the operation of HDI, TDI, SDI technologies is based on the third generation Common Trail system, which is characterized by the use of piezoelectric injectors, which make it possible to make injection more accurately and increase fuel supply pressure. In principle, it is believed that all engines that have such markings have little differences, and their symbolism is a determinant of the performance of power units. That is why it is quite difficult to single out a leader from these three names. The only conclusion that can be drawn is to recognize the fact that the choice of a diesel engine is justified and promising.

TDI engine ( Turbocharged Direct Injection, literally - turbocharger and direct injection) is a modern turbocharged diesel engine. The engine was developed by the Volkswagen Group, and the TDI name is a registered trademark.

Turbocharging of the TDI engine ensures high vehicle dynamics, efficiency and environmental safety. To create optimal boost pressure over a wide range of speed conditions, the engine design uses a turbocharger with variable turbine geometry. Turbocharger has two common names, which are used by different manufacturers:

VGT, Variable Geometry Turbocharger(literally – variable geometry turbocharger) uses BorgWarner;
VNT, Variable Nozzle Turbine ( literally - variable nozzle turbine) is used by Garrett.

Unlike a conventional turbocharger, a variable geometry turbocharger can regulate the direction and magnitude of exhaust gas flow, thereby achieving the optimal turbine speed and, accordingly, compressor performance.

The VNT turbine combines guide vanes, a control mechanism and a vacuum drive. The guide vanes are designed to change the speed and direction of the exhaust gas flow by changing the size of the channel cross-section. They rotate at a certain angle around their axis.

The blades are rotated using a control mechanism. The mechanism consists of a ring and a lever. The control mechanism is activated by a vacuum drive acting through a rod on the control lever. The operation of the vacuum drive is regulated by a boost pressure limiting valve connected to the engine management system. The boost pressure control valve is activated depending on the boost pressure measured by two sensors: the boost pressure sensor and the intake air temperature sensor.

Working principle of supercharging a TDI engine

The TDI engine's charging system ensures optimal air pressure over a wide range of engine speeds. This is achieved by regulating the energy of the exhaust gas flow.

At low engine speeds exhaust gas energy is low. To use it effectively, the guide vanes are in the closed position, in which the exhaust gas channel area is smallest. Due to the small cross-sectional area, the flow of exhaust gases is enhanced and causes the turbine to rotate faster. Accordingly, the compressor wheel rotates faster, and the performance of the turbocharger increases.

With a sharp increase in engine speed, due to the inertia of the system, the energy of the exhaust gases becomes insufficient. Therefore, to pass through the “turbo lag,” the blades rotate with some delay, thereby achieving the optimal boost pressure.

At high engine speeds exhaust gas energy is maximum. To prevent excess boost pressure, the blades are rotated to a maximum angle, providing the largest cross-sectional area of the channel.

Turbocharging of a TDI engine - purpose, design and operating principle

The TDI engine (Turbocharged Direct Injection) is a modern turbocharged diesel engine developed by the Volkswagen Group. The TDI brand is a registered trademark.

Purpose of turbocharging

Turbocharging of the TDI engine ensures the vehicle's efficiency, high dynamics and environmental safety. The creation of optimal boost pressure is achieved through the use of a turbocharger with variable turbine geometry in the engine design.

Turbocharger has two common names used by different manufacturers:

VGT (English: “Variable Geometry Turbocharger” - “variable geometry turbocharger”) - used by BorgWarner;
VNT (Variable Nozzle Turbine) - used by Garrett.

TDI engine turbocharging:
A - air; B - exhaust gases.
1 - vacuum line; 2 - engine control unit; 3 - boost pressure and intake air temperature sensors; 4 - air damper control unit; 5 - intercooler; 6 - exhaust gas recirculation valve; 7 - boost pressure limitation valve; 8 - turbocharger; 9 - intake manifold; 10 - vacuum drive of guide vanes; 11 - exhaust manifold.

A variable geometry turbocharger, unlike a conventional turbocharger, can control the direction and flow of exhaust gases. This ensures optimal turbine speed and accordingly increases compressor performance.

The design of a variable nozzle turbine involves the integration of guide vanes, a control mechanism and a vacuum drive.

VNT turbine (variable geometry turbine):
1 - guide vanes; 2 - ring; 3 - lever; 4 - vacuum drive rod; 5 - turbine wheel.

Guide vanes are designed to change the direction and speed of exhaust gas flow by changing the size of the channel cross-section. The blades rotate around their axis at a certain angle using a control mechanism. This mechanism consists of a lever and a ring.

The vacuum drive operates the control mechanism by acting through the rod on the control lever. The boost pressure control valve, connected to the engine management system, regulates the operation of the vacuum drive. This valve is activated depending on the boost pressure value measured by two sensors: the intake air temperature sensor and the boost pressure sensor.

How does supercharging work on a TDI engine?

The TDI engine's charging system ensures optimal air pressure during operation over a wide range of engine speeds. This is achieved by regulating the energy of the exhaust gas flow.

At low engine speeds, the energy of the exhaust gases is small. In order to effectively use this energy, the guide vanes are installed in the closed position, in which the smallest value of the exhaust gas channel area is achieved. Due to the small cross-sectional area, the flow of exhaust gases increases and causes the turbine to rotate faster, which in turn rotates the compressor wheel and thereby increases the performance of the turbocharger.

With a sharp increase in engine speed, the energy of the exhaust gases becomes insufficient. In this regard, to pass the “turbo lag”, the rotation of the blades is carried out with some delay, which ensures acceptable boost pressure.

The energy of exhaust gases is maximum at high engine speeds. To prevent excess boost pressure, the blades rotate to a maximum angle, thereby providing the largest cross-sectional area of the channel.

Video:

I hope everything was clear. Good luck on the roads!

What is the difference between HDI, TDI and SDI engines

Today, economy can be called one of the most important and decisive factors of all that influence the purchase of a car. This concept includes more economical fuel consumption and a longer service life of the unit itself. And as always, when resolving this issue, the fight between diesel and gasoline comes to the fore. At the same time, it can be noted that both one and the second type of engine have a sufficient number of pros and cons. At the same time, it is possible to make it possible to have a diesel-like type to know how to know how to get 25-50%, and the consumption of their life is long. .

So what is better: diesel or gasoline? First of all, it is worth noting that the popularity of diesel units in Russia is much less than their popularity in Europe. Although there are definitely fans of such engines, and their number is constantly growing. The demand for diesel in Europe is quite large and for this reason, European automobile companies are constantly improving engines of this type. This desire for improvement became the reason that diesel engines began to appear on the market, which have some differences in design. The most famous among them are models with the abbreviations HDI, TDI, SDI. Therefore, in this article we will try to figure out how exactly these models differ from each other?
If we talk about markings, the letters DI mean that this model uses a system whose operation is based on direct injection of fuel into the SG chamber Opania. The operating principle of such a system is based on the fact that the injectors have a common channel into which fuel flows under fairly high pressure. The abbreviation HDI and SDI means the absence of turbocharging, that is, these diesel engines can be called atmospheric-type devices. In turn, models labeled TDI are distinguished by the presence of turbocharging, which significantly affects the increase in engine efficiency.

HDI diesel engine

Diesel engines, which are designated by this abbreviation, are the development of one of the automotive giants, the PSA Peugeot Citroen concern. These power units use the Common Rail system in their operation. This system, which is characterized by direct injection of fuel into the combustion chamber, has made it possible to reduce fuel consumption by 15%, increase power by 40%, and also reduce noise level by 10 dB. HDI diesel engines have a longer service life. Thus, it can be noted that diagnostics at a service station can be carried out based on the calculation of once every 30 thousand km. In addition, it can be noted that the timing belt, as well as the belts of mounted units, do not cease to function throughout the entire service life of the engine.

Diesel engine TDI

As mentioned earlier, the TDI diesel engine uses turbocharging, which provides the ability to increase power. At the same time, economy indicators remain at a high level, and exhaust purity always fully complies with standards. For the first time, such engine models began to be used by the Volkswagen concern. Models of this type are distinguished by their reliability and ease of operation. The only drawback of TDI diesel engines is the short service life of the turbine, which is rated at 150 thousand. km. But the engine itself has a resource of one million kilometers.

SDI engine

Those who are not attracted by the prospect of expensive repairs can be advised to pay attention to the engines of the SDI model. This modification of power units is distinguished by greater resistance to mileage, as well as reliability, which is ensured by the simplicity of the design.
Today, it can be noted that the operation of HDI, TDI, SDI technologies is based on the third generation Common Rail system, which is distinguished by the use of piezoelectric injectors, which make it possible to perform injection more accurately and increase the fuel supply pressure. In principle, it is believed that all engines that have such markings have few differences, and their symbolism is a determinant of the performance of power units. That is why it is quite difficult to single out a leader from these three names. The only conclusion that can be drawn is to recognize the fact that the choice of a diesel engine is justified and promising.

TDI engine: what is it?

Overall assessment of the benefits of TDI

Among the identified advantages of the Turbocharged Direct Injection power plant, one cannot help but pay attention to the following:

power;
efficiency;
compactness;
environmental friendliness.

The role of the variable geometry turbine

In general, a TDI turbine is a kind of exhaust flow energy dispenser that provides the required air pressure in any engine operating mode.