What is the difference between a two stroke engine and a four stroke engine?

<> the so-called four-stroke engine, it means that the engine crankshaft rotates every two weeks and goes through four strokes of air intake, compression, work and exhaust to complete a working cycle, while a two-stroke engine only needs to rotate the crankshaft for one week and go through two strokes to complete a working cycle.

From the structural point of view, the structure of the two-stroke engine is relatively simple, mainly composed of cylinder heads, cylinders, pistons, piston rings and other parts, and there are air intake, exhaust and ventilation holes on the cylinder block; The opening and closing of the air holes is determined by the position of the piston. Compared with four-stroke engines, there is no complex valve mechanism and lubrication system, and the cooling system is generally air-cooled, which is greatly simplified in structure.

In terms of performance, when the crankshaft speed is the same, a two-stroke engine can do twice as much work per unit time as a four-stroke engine. Theoretically, a two-stroke engine should have twice as much power as a four-stroke engine (but in practice it is only double), the engine has a higher liter power, better power, and less vibration of the engine. In addition, the two-stroke engine is lighter, the manufacturing cost is low, the failure rate is lower, the maintenance is more convenient, and the use is more convenient and flexible.

On the whole, four-stroke engines are more widely used, and the vast majority of automobiles and construction machinery are equipped with four-stroke engines, while two-stroke engines are more used in those occasions where they are not often used and the "thrust-to-weight ratio" is very important. For example, lawn mowers, chain saws, model airplanes, agricultural machinery, etc., some small motorcycles and off-road motorcycles that pay more attention to power performance are also widely used. There are tanks, ships, heavy transport vehicles, etc., these models have high requirements for the power of the engine, and require the engine to be light in weight and small in size, and the two-stroke engine is a good choice.

A four-stroke engine has a more powerful power stroke than a two-stroke engine!

In fact, it is useless to say so much, the key is that two-strokes burn engine oil and gasoline, and four-strokes only burn gasoline. (in the case of a good engine).

Two-stroke engines and four-stroke engines are more durable, depending on their quality, as well as their use and maintenance. From the perspective of engine working principle alone, two-stroke engine and four-stroke engine have their own advantages and disadvantages, both have advantages and disadvantages to the reputation of durability, so only from the working principle of the two engines, it is impossible to determine which engine is more durable, and it is not as important as their own quality.

The advantage of the two-stroke engine is that the structure is simple, and the engine has few parts, especially the parts of the valve system, so that the probability of its failure and parts damage may be less. However, the two-stroke engine is also conducive to reducing engine failures due to the faster frequency of work, and the engine is not perfect because the engine burns mixed oil, and it is also more prone to carbon deposits. In addition, the two-stroke engine is more fuel-intensive than the four-stroke engine of the same displacement, in addition to burning more gasoline, the oil is usually mixed with gasoline in a certain proportion and burned, so as to provide lubrication for the crankshaft connecting rod of the engine and the piston moving part of the cylinder block.

Compared with the two-stroke engine, the structure of the four-stroke engine is much more complex, and because the structure is complex and there are many parts, the possibility of failure and damage to the parts is relatively more. However, the working principle of the four-stroke engine is more reasonable and stable than the two-stroke engine, and the lubrication efficiency of the engine lubrication system is also higher, and due to the good lubrication and heat dissipation, the engine work frequency is not as high as that of the two-stroke engine, so from this aspect, it is conducive to reducing the failure rate and the four-stroke engine is more fuel-efficient, and the exhaust emissions are also cleaner.

Therefore, in the end, which engine is durable, the most important thing is its own quality, as well as the usual use and maintenance standards.

Answer]: Compared with the four-stroke engine, the two-stroke engine has the following characteristics: the crankshaft completes a working cycle every revolution, and the work is a high wax pin, which has a large power and stable operation; Due to the use of pores for ventilation, there is no or less valve mechanism, simple structure, small size, light weight, manufacturing, maintenance, easy to use, low cost.

However, due to the short and simple ventilation time, the exhaust is not easy to be clean, and part of the work stroke is lost during ventilation, and there is always a part of the mixture due to exhaust gas loss (gasoline engine) and power consumption of the sweeping pump during scavenging, resulting in poor economy and serious exhaust pollution. At the same time, due to the high frequency of combustion work, the heat load is high and the noise is large.