Ford

The operating principle of a two-stroke engine, are there any advantages over a four-stroke engine? Two-stroke diesel engine - how it works 2-stroke engine

At the moment, there are two main types of internal combustion engines - two-stroke and four-stroke. They are practically the same in appearance, but two-stroke engines operate on a completely different principle. Let's try to understand the main differences between these two types of internal combustion engines, and how a two-stroke engine works.

Operating principle of an internal combustion engine

In order for your car to perform its direct function - to transport you, it needs to be filled with fuel: gasoline, diesel, propane-butane. Gasoline enters the engine through the fuel line; the main work in it is performed by the pistons and the crank mechanism. Gasoline is mixed with air, a mixture is formed that explodes and sets the pistons in motion, this moment of movement is transmitted to the crankshaft, and from it to the transmission.

The difference between 2 and 4 stroke engines, as the name suggests, is the number of strokes, that is, the duty cycle of the engine. The operating cycle of any internal combustion engine is a sequence of the following processes:

filling the cylinder with a combustible mixture;
its ignition;
expansion of gases;
displacement of combustion products.

In a 4-stroke engine, this entire sequence is carried out in 4 strokes, that is, in two revolutions of the crankshaft, in a two-stroke engine - in one revolution. From this we can conclude that 2-stroke engines have more power, and this is true, it’s not for nothing that they are used not only for motorcycles, mopeds, various ATVs, snowmobiles and jet skis, but also to propel huge sea ships.

Theoretically, the power should be twice as high. For example, a small-sized motorcycle engine can easily produce a power of one hundred or more horses, while a much more massive and voluminous engine of a class “B” or “C” car produces 70-100 hp.

Two-stroke engine design

The main advantage of two-stroke engines is the simplicity of their design. Since all processes in the operating cycle are completed in one revolution of the crank, there is no need for a complex timing mechanism that controls the movement of the intake and exhaust valves. The intake valve closes and opens due to the pressure difference, and the exhaust gases exit through the exhaust port to the muffler.

Also, a 2-stroke engine is cooled using fuel into which a certain percentage of oil is mixed. It is necessary to select two-stroke oil, since it is adapted to high temperatures and leaves less slag and ash during combustion.

The piston moves from bottom dead center to top dead center - BDC and TDC. During its upward movement, the piston compresses the incoming air-fuel mixture. At TDC, the mixture explodes and the piston begins to move downwards, at which point a new portion of the mixture arrives. It turns out that the piston itself pushes out the exhaust gases, and this is the main disadvantage of two-stroke engines, affecting their efficiency.

Disadvantages of two-stroke engines

Despite the fact that engineers are trying to solve them, there are still shortcomings and they are significant.

The most important of them is inefficient use of fuel and increased CO2 emissions.

If in four-stroke engines a separate stroke is allocated for the removal of exhaust gases and combustion products, here this stroke is combined with filling the cylinder with a new portion of the combustible mixture, and no matter how hard the engineers try, it is impossible to avoid mixing it with the exhaust gases.

In addition, it is necessary to constantly add oil to gasoline, and it is quite expensive and is consumed faster.

Because of these problems, engine power is also reduced. Theoretically, it should be twice as high as that of 4-stroke internal combustion engines, but in reality this figure does not exceed 50-70 percent. After 2000, many manufacturers abandoned two-stroke internal combustion engines. However, work to improve them is constantly underway.

Video of the operating principle of this type of engine.

Today it is impossible to imagine modern life without. Traveling in your own car, traveling on public transport, purchasing goods, flying on an airplane and other actions. These processes are one way or another connected with the engine.

Despite the number of different designs and types of power plants, piston engines today are more common than others. The number of strokes to complete the working cycle divides the unit into a two-stroke and a four-stroke engine. These types of motors make up the majority among the variety of manufactured equipment.

The difference between motors arises from the application point of view. For installation on automotive equipment, a four-stroke unit is more often used; a two-stroke engine is used if dimensions and weight play a decisive role.

Suzuki RM125 motorcycle with single-cylinder two-stroke engine

Creation of a two-stroke engine

There are many speculations about who was the first to create an internal combustion engine. It is known for certain that the first two-stroke engine running on gas was invented and designed by the Belgian Jean Joseph Etienne Lenoir; this event occurred in 1858.

Lenoir engine (on display in the museum)

At that time, a steam engine had already been created, and the Belgian’s invention surpassed it in characteristics. The engine is much lighter, simpler, and consumes less fuel. Despite the advantages, the power plant had many shortcomings and was inferior in reliability. After Nicholas Otto presented a four-stroke engine, which at that time was thought out in more detail, the engine operating on the two-stroke principle was forgotten, and was not used anywhere for a long period of time.

During the Great Patriotic War, the power plant was installed on aircraft. In our region, motors are known for their use on moto equipment. Three-cylinder units performing two strokes are used on motorcycles from Suzuki and Kawasaki. Today, engines are used in aviation; the leader here is the Austrian company Rotax, which produces engines for use on small aircraft.

Rotax 582 UL two-stroke twin-cylinder engine

After stricter requirements for environmental standards and emissions, the two-stroke engine was no longer used for installation in classic automobile vehicles. However, on light equipment such as scooters, snowmobiles, boats, replacing a small and light unit is not easy. Here the two-stroke unit simply has no competitors.

Features of a two-stroke engine

A power unit that uses two strokes is good because it is simple and reliable. The difference between a two-stroke and a four-stroke engine is the duty cycle. This cycle consists of two strokes: compression and expansion, whereas in a four-stroke engine there is an intake stroke of new fuel and an exhaust stroke of spent fuel. An interesting fact is that these two strokes are also present in a two-stroke power plant, otherwise the unit would not be able to work, but they are combined with the processes of compression and expansion.

The cycle being performed clearly demonstrates the difference between a two-stroke engine and a four-stroke engine. The process of a two-stroke motor takes place per revolution of the shaft. This feature achieves installation in comparison with the opponent, one and a half times. Despite the increase in power, the return rate is underestimated, which is a negative point.

In addition, this feature leads to the release of a volume of heat during operation, which greatly overheats the motor. Two-stroke power units require intensive cooling. The positive thing is that when working, the piston makes half as many movements as the piston of a four-stroke mechanism, this reduces wear on parts and elements.

The peculiarity of the unit is that there is no lubrication mechanism. Oil is supplied directly with fuel. For this purpose, a mixture of gasoline and oil is added to the gas tank, the ratio is one to fifty, or the lubricant is mixed with fuel in the pipeline at the inlet. The oil burns with gasoline and is removed with waste products.

The distinctive moment is the combustion itself. In a four-stroke unit, one cycle is allocated for this. In push-pull units, combustion occurs in a fraction of a second, so the mechanism needs adjustments to achieve the effect.

Two-stroke engines have found themselves in another industry, shipbuilding. Cylinder power plants are also used on scooters produced in large quantities.

Operating principle of a two-stroke engine

To understand why four-stroke engines have replaced their younger brothers in automotive technology, let’s look at how a two-stroke engine works.

Sequence of actions of the power plant operating cycle:

Compression stroke.

The process is accompanied by the movement of the piston from bottom to top. The movement provokes the flow of fuel through the purge holes into the unit; subsequently, the piston skirt blocks these holes. Further movement is accompanied by the closure of the exhaust channels into which combustion waste was pushed out. Between the piston and the top of the cylinder, a combustion space is formed in which excess pressure is created. At the same time, a vacuum occurs in the space under the piston, and the space is used for the flow of a renewed dose of fuel. Having reached the top point, the charge lights up.

Two-stroke engine diagram

Expansion stroke.

Having ignited, the portion creates excess pressure, which presses on the bottom of the piston and forces it to move. The process is accompanied by alternate opening of the windows, first for exhaust, then for purging. The descent creates excess pressure under the piston chamber; under its influence, fuel again enters the cylinder, squeezing out the remaining waste and filling the space to repeat the previous stroke.

The operating principle of a two-stroke engine makes it possible to do without a gas distribution system, making the design of the unit lighter and more reliable. The downside is the quality of the gas exchange process. The two-stroke mode is impossible without purging, the process of which is accompanied by the release of unburned fuel along with exhaust gases to the outside. This leads to excessive consumption of fuel and increased toxicity of the unit's exhaust.

It is worth noting that the above described scheme is typical for carburetor engines. In the case of a diesel engine or, clean air is supplied to the cylinder through the purge holes. The combustible mixture is supplied through injection; this work is performed by injectors.

Methods for purging cylinders

It is obvious that the purging process, a mechanism that qualifies as complex. Properly performed purging directly affects power and efficiency indicators. To improve performance, designers are constantly trying to improve and bring the process to perfection.

How to blow out a cylinder:

“Circuit” blowing. This type of blowing is simple and therefore widespread. The disadvantage is that the application is associated with excessive fuel consumption. Types of contour blowing: return-loop, deflector, high-altitude.

“U-shaped” purging. The “U-shaped” principle is to be used only on engines with two cylinders. When carrying out, one cylinder participates in the process of gas intake, the second releases waste. The effect of purging is felt in fuel efficiency; the process is accompanied by uneven heating of the steam responsible for the exhaust.

“Valve-slit” purge. It differs in that it requires a gas distribution mechanism to control the valves. The valve is used both to provide fuel and to remove exhaust vapors. Purge involves the removal of waste through a valve in the cylinder head and the flow of fuel through the holes. The advantage is that purge increases fuel efficiency and minimizes the toxicity of emitted vapors. Disadvantage, complexity of design and violation of regimes associated with an increase in the operating temperature of the unit.

“Direct flow” blowing. Used in power plants with the number of pistons equal to two. In this case, the cylinder is located in a horizontal position. The pistons move towards each other. In motion, each piston releases and closes the valve: one piston admits a portion of fuel, the second removes a portion of waste from the cylinder. The combustion chamber is formed when the pistons approach each other. The effect of this purge option is maximum: it removes burnt gases and saves fuel. The downside is that a complex mechanism of cranks and connecting rods is required; the performance requires the use of coolers and sustainable materials for the manufacture of parts.

Two-stroke engine 5 TDF with direct-flow purge

The difference between a two-stroke engine and a four-stroke engine

Car owners are wondering: which is better, a two-stroke or a four-stroke engine. There is no definite answer; each mechanism has positive and negative sides, depending on the requirements placed on the motor.

It would seem that the power of a motor performing two strokes, in comparison with an equivalent motor performing four strokes, is greater, which means it is better. However, the reality is more complex. In practice, additional losses occur: partial ingress and mixing of waste gas with fresh fuel, release of part of the fuel during purging. The result is that when performing the same cycle, a unit that performs two cycles is inferior in terms of efficiency to a unit with four cycles.

The method of lubrication of four-stroke and two-stroke power plants is different. The two-stroke unit is lubricated by mixing engine oil and gasoline. The four-stroke unit has a lubrication mechanism using a pump, which consumes as much oil as the operation of the installation requires.

Two-stroke engines do not have valves; the role of the part is played by the piston; it opens and closes the intake and exhaust ports. The absence of gas distribution mechanisms simplifies the power unit, making maintenance simple. The power of an installation that performs two cycles is considered higher, since its cyclicity is higher. However, without fully using the piston stroke, power losses during purging and exhaust gas residues reduce the power rating.

To make it easier to determine which engine is better, two-stroke or four-stroke, we present a brief description of both power plants in the form of a table:

Four-stroke power plant	Two-stroke power plant
The working process is two crankshaft revolutions.	The working process is one crankshaft revolution.
Ignition of the working fluid occurs every time the second revolution is made, as a result, uneven distribution of the impulse and the use of a counterweight to eliminate beats.	Ignition of the working fluid occurs every time a revolution is made, as a result, the impulse is evenly distributed, and the operation of the motor is better balanced.
The unit is heavy.	The unit is lightweight.
The complex design of the power plant includes a gas distribution mechanism.	Simplicity of design, absence of valves.
The unit is expensive.	The cost is lower than the four-stroke.
Complex devices and mechanisms lead to an underestimated mechanical efficiency.	The mechanical efficiency is higher than that of a four-cycle unit.
Complete removal of exhaust vapors, resulting in increased productivity.	The waste residues are mixed with new fuel, causing engine performance to be lower.
Operating temperature is lower.	The operating temperature of the engine is higher due to a violation of mixture formation.
Liquid cooling.	Air cooling.
Fuel consumption is lower.	The fuel consumption rate is increased due to mixture formation and purging.
The dimensions of the power plant have been increased.	The dimensions of the power plant are below.
Requires the use of complex lubrication mechanisms.	The lubrication mechanism is simple.
The unit operates less noisily.	The unit operates with a lot of noise.
Valve timing mechanism.	The function of the gas distribution mechanism is performed by the piston and channels.
The heat utilization rate is efficient.	The heat utilization rate is not efficient.
Oil consumption is underestimated.	The oil consumption rate is overestimated, since part of the lubricant is thrown out with exhaust gases.

It is advisable to use an engine that performs two strokes during operation in moments when fuel and lubrication savings are not at issue, but the dimensions and weight of the installation come first.

At the same time, the design of a two-stroke engine contains potential that cannot be realized in practice. The calculated indicator of power and efficiency in this unit is high; the difficulty in implementing it arises due to the subtlety of the settings. Perhaps in the near future, thanks to the use of electronic sensors and control and adjustment mechanisms, two-stroke units will be able to take a leading position in the automotive market.

There are two main types of engines: two-stroke and . In two-stroke engines, all operating cycles (processes of inlet of the fuel mixture, exhaust gases, purge) occur within one revolution in two main strokes. Engines of this type do not have valves; their role is played by a piston, which, when moving, closes the intake, exhaust and purge windows. Therefore, they are simpler in design.
The power of a two-stroke engine with the same cylinder dimensions and shaft speed is theoretically twice that of a four-stroke engine due to the greater number of operating cycles. However, incomplete use of the piston stroke for expansion, poorer release of the cylinder from residual gases and the expenditure of part of the generated power on purging lead to an increase in power by only 60...70%.

The engine consists of a crankcase in which the crankshaft and cylinder are mounted on bearings on both sides. A piston moves inside the cylinder - a metal cup surrounded by spring rings (piston rings) inserted into grooves on the piston. Piston rings prevent gases generated during fuel combustion from passing between the piston and the cylinder walls. The piston is equipped with a metal rod - a pin; it connects the piston to the connecting rod. The connecting rod transmits the linear reciprocating motion of the piston into the rotational motion of the crankshaft.
All rubbing surfaces and bearings inside two-stroke engines are lubricated using a fuel mixture into which the required amount of oil is mixed. The figure shows that the fuel mixture (blue color) enters both the crank chamber of the engine (this is the cavity where the crankshaft is fixed and rotates) and the cylinder. There is no lubricant there anywhere, and even if there was, it would be washed off with the fuel mixture. This is the reason why oil is added in a certain proportion to gasoline. The type of oil used is special, specifically for two-stroke engines. It must withstand high temperatures and, when burned together with the fuel, leave a minimum of ash deposits.

Principle of operation. The entire working cycle in the engine is carried out in two strokes

1. Compression stroke. The piston moves from the bottom dead center of the piston (in this position the piston is at the bottom dead center, hereinafter we call this position for short BDC) to the top dead center of the piston (hereinafter TDC), blocking first the purge and then the exhaust window. After the piston closes the exhaust window in the cylinder, compression of the combustible mixture that previously entered it begins. At the same time, in the crank chamber, due to its tightness and after the piston closes the purge windows, a vacuum is created under the piston, under the influence of which a combustible mixture enters the crank chamber from the carburetor through the inlet window and the slightly open valve.

2. Power stroke. When the piston is positioned near TDC, the compressed working mixture is ignited by an electric spark from the spark plug, as a result of which the temperature and pressure of the gases increase sharply. Under the influence of thermal expansion of gases, the piston moves to BDC, while the expanding gases perform useful work. At the same time, going down, the piston creates high pressure in the crank chamber (compressing the air-fuel mixture in it). Under the influence of pressure, the valve closes, thus preventing the combustible mixture from entering the intake manifold again and then into the carburetor.
When the piston reaches the exhaust window, it opens and exhaust gases begin to be released into the atmosphere, the pressure in the cylinder decreases. With further movement, the piston opens the purge window and the combustible mixture compressed in the crank chamber flows through the channel, filling the cylinder and purging it of exhaust gas residues.

Ignition principle. Since the fuel mixture takes time to ignite, the spark appears at the plug a little earlier than the piston reaches TDC. Ideally, the faster the piston moves, the earlier the ignition should be, because the piston reaches TDC faster from the moment of spark. There are mechanical and electronic devices that change the ignition angle depending on engine speed. Almost for scooters up to 2000. There were no such systems and the ignition timing was set based on optimal speed.

Advantages of two-stroke engines:

No cumbersome lubrication and gas distribution systems
. High power per 1 liter of working volume
. Easier and cheaper to manufacture
. Less weight

Disadvantages of two-stroke engines:

1. Higher fuel consumption. Let us remind you that the approximate consumption can be calculated using the formula: for a two-stroke 300 grams per horsepower, for a four-stroke 200 grams.
2. Noisy. At maximum speed, two-stroke engines tend to be slightly louder than four-stroke engines.
3. Comfort. they do not vibrate as much at low speeds (Applies only to two-cylinder engines. Single-cylinder and two-stroke and four-stroke engines vibrate approximately the same) and do not smoke as much as two-stroke engines.
4. Durability. Quite a controversial point. There is an opinion that two-stroke engines are less durable. On the one hand, this is understandable, because the oil for lubricating the rubbing elements of the engine is supplied along with gasoline, which means it does not work as efficiently as in four-stroke engines where the rubbing elements literally float in oil. But on the other hand, a four-stroke engine is much more complex in design than its competitor, consists of a much larger number of parts, and the golden principle of mechanics “The simpler the more reliable” has not yet been canceled.

Good day everyone, dear readers! Despite the fact that most of you are owners of four-wheeled vehicles, there are also connoisseurs of motorcycles, mopeds, and scooters among subscribers. If you don’t yet know the principle of operation of a two-stroke engine, then it’s time to familiarize yourself with this interesting topic.

This type of power unit has become the basis for various types of devices and equipment due to its simplicity and reliability. The operating cycle of such a motor has only two strokes, unlike the 4-stroke engines that are installed on most cars. This pair of bars is compression and expansion. The reader may quite rightly wonder: where does the inlet and outlet of the working mixture go? The fact is that they are combined with the compression and expansion mentioned above.

Unlike a 4-stroke engine, in a 2-stroke engine the entire working cycle occurs in just one revolution of the crankshaft. This makes it possible to increase the power quality of the engine by 1.5 times or more with an equivalent displacement. However, this leads to a decrease in efficiency, otherwise all self-propelled mechanisms without exception would be equipped with such power units. But in shipbuilding they have found the widest application. A single-cylinder two-stroke engine is also an integral component of every small-engine scooter that roams our roads with might and main.

Another important feature of such mechanisms is their tendency to overheat. This is due to the release of large amounts of heat during operation. To solve this problem, forced cooling may be required. But there are also advantages to such a motor: the work of the piston is limited to 2 strokes, which means that it makes half as many movements. Due to this, wear on key parts of the power unit is reduced.

Operating principle

Let's look at how such an engine works in practice (see video):

The piston begins to move upward from the bottom point, which is also called the “dead” point. Simultaneously with this process, fuel is delivered along with air. The exhaust window opens slightly, and exhaust gases escape freely through it. In this case, the moment of compression of the working mixture occurs.
As soon as compression begins, a space is formed in the crank chamber based on rarefied air. This frees up space for a fresh supply of fuel. When the piston reaches the top point of movement, the spark plugs produce a spark that ignites the working mixture.
As a result of the combustion of the working mixture, energy is generated that forces the piston to move downwards. The excess pressure created in the crank chamber causes the fuel to compress. At the top point of the piston movement, the exhaust window opens, freeing the exhaust gases to exit, from where they are sent straight to the muffler.
Further movement of the piston leads to the opening of the purge window. Fuel moves from the crank chamber to the working cylinder. As soon as the piston reaches the lowest point, this means that the full cycle of engine operation has taken place. And everything starts again, but this will be the beginning of a new cycle.

Comparison of 2 and 4 stroke engines

Since the power of an equivalent motor is two strokes greater than that of its 4-stroke counterpart, it should, in theory, be more economical. In practice, this does not happen due to additional losses that arise. Partial mixing of the exhaust gases with the newly incoming fuel occurs, and this entire mixture safely exits through the exhaust pipe. Therefore, for the same number of cycles, a two-stroke carburetor requires more fuel.

There are also differences in the lubrication system. In the case of a 2-stroke motor, it is carried out by mixing and. The 4-stroke engine has a lubrication system with a gear pump. Lubricant enters the inlet pipe of the system, and it is supplied exactly as needed.

Such engines do not have valves, which are inherent in four-stroke internal combustion engines. For them, the same work is done by a piston, which, when moving sequentially up and down, opens and closes the purge, inlet and outlet windows. Due to this, they are considered more structurally simple and easier to maintain. It is believed that their power rating is approximately 2 times higher than those designed for 4 cycles, due to the greater number of cycles passed.

But due to insufficient use of the piston stroke, residual accumulated gases in the cylinder and partial loss of produced power for purging, the actual increase in net power will be no more than 60–70 percent. The spark on such engines appears a fraction of a second earlier than the piston reaches top dead center, and various mechanical and electronic devices are provided to change the ignition angle. On previous models, the ignition moment was set based on the optimal speed.

So, let’s summarize the main advantages of the power unit in question:

differs in small dimensions;
has a simple device;
produces more power with the same displacement.

At the same time, its use is limited due to design features and significant losses. However, today this type of engine is still equipped with a large number of different mechanisms that can use both a single- and two-cylinder internal combustion engine for 2 strokes. Knowing the features and operating principle of such an engine, you can independently find problems that arise in it. In some cases, such knowledge allows you to decide between a 2-stroke and a 4-stroke power unit.

In today's review, we tried to look at the design of a 2-stroke power unit, which is equipped with almost any modern motorcycle or moped, as well as other equipment. Friends, I will be grateful for your recommendations of my blog among your friends. In the upcoming blog releases, we will definitely look at new interesting topics in the field of cars. In the meantime, a few words about and what is the point of using them. Stay with us and see you again!

Modern mechanical engineering is ready to present various types of engines and mechanisms that, one way or another, make human life easier. One of these power units is considered to be a two-stroke internal combustion engine. In this article we will look at its detailed operating principle, structure, advantages and disadvantages, as well as application.

A two-stroke internal combustion engine is a piston engine in which air-fuel combustion occurs not in the combustion chamber, as in four-stroke engines, but directly in the working cylinder itself. The design of such an engine is not much different from the design of a four-stroke engine. It contains all the same parts as a regular piston internal combustion engine - a piston, a cylinder and a crank mechanism.

A piston is installed in the cylinder block, inside of which a connecting rod is mounted using a special bushing. The crankshaft is also located at the bottom of the connecting rod. The crankshaft is suspended by two bearings and immersed in a special crankcase. The main feature of such an engine is that the lubricant and fuel are mixed into one mixture and supplied along with air into the combustion chamber.

It is generally accepted that the power of a two-stroke engine is much higher than that of a four-stroke engine, but if you consider how much work the engine does on such a short piston stroke, we can conclude that its efficiency is too low.

Operation of a two-stroke internal combustion engine

As is already clear from the name, such an engine has only two power strokes, which will be described below.

First bar (compression). The piston is at the bottom dead center of the engine and begins to move upward. During the lifting process, a certain amount of fuel, mixed with oil and air, enters the cylinder through the blow hole. As soon as the piston reaches the hole, it closes and the flow of the mixture stops. At the same stage, the outlet hole is also closed. The piston moves to top dead center and compresses the mixture.
Second stroke (piston stroke). At top dead center the mixture is compressed and ignited. As a result of a small explosion, the piston, under the influence of high pressure, begins to move downwards, thereby opening the exhaust port and making it possible to free the cylinder from exhaust gases. Part of the oil in the mixture remains on the cylinder walls, and the other part simply exits along with the exhaust gases. The piston reaches bottom dead center and the cycle begins all over again.

It is worth noting that for more successful spark formation, the spark should occur a little earlier than the piston reaches top dead center. An ideal ignition is one that produces a spark even earlier as the engine speed increases. Such a system was completely absent until the 2000s. In those days, spark generation was adjusted to optimal speed, and therefore the engine worked inefficiently. Currently, special electronic switches are used, which have dynamic advance at the moment of ignition. It changes with increasing or decreasing engine speed.

Advantages of a two-stroke engine over a four-stroke engine

Small dimensions of the power plant. Such an engine requires very little space, which easily explains their use on motorcycles.
Less weight compared to a conventional four-stroke engine.
Economical fuel consumption. This only applies to the diesel engine when fuel consumption is only 50% of average.
Simplicity and ergonomic installation. The design of a two-stroke engine is not complicated, and therefore can be easily maintained and repaired.

Disadvantages of two-stroke engines

With a decrease in fuel consumption, oil consumption increases significantly, since it is poured into the engine gas tank along with fuel. The fact is that the design of such a power plant does not allow for a special tank for storing lubricant. In this connection, it becomes necessary to add oil to the air-fuel mixture.
Since air consumption in such engines increases significantly, a special design becomes necessary.
Due to the nature of the intake and exhaust systems, there is a huge possibility of unintentional mixture of exhaust gases with the fresh mixture.
The choice of two-stroke engines on the market is seriously limited. This makes their cost quite high.
Inefficient engine operation. This design does not allow creating a high efficiency.

Application of two-stroke engines

Two-stroke engines are most widely used in motor vehicles. Having a very small size, such a motor can be used on mopeds, motorcycles and scooters. In addition, engines of such dimensions are widely used in gasoline saws. The fact is that to bring the chain into action you don’t need high performance at all; the main thing is to create a certain rotation speed at which the chainsaw will be able to cope with its main responsibilities.

In addition to motorcycles, cars were also rarely equipped with two-stroke engines. As a rule, these were small runabouts designed for traveling short distances around the city. Two-stroke engines are still used today on many motor boats.

That's all you need to know about two-stroke internal combustion engines. Despite all the advantages and disadvantages of this motor, many designers prefer four-stroke engines, so the small-volume motor has not found wide distribution.