In internal combustion engines, the chemical energy of the fuel combusted in its working cavity, in the combustion chamber, is converted into mechanical energy. Another more popular name for an internal combustion engine is a motor.
Motor translated from it. means engine, this word, in turn, comes from the Latin. motor -. The invention of internal combustion engines was a pivotal moment in the development of the era of road transport. The use of internal combustion engines is very diverse. They set in motion airplanes, sea vessels, as well as simpler mechanisms - pumps, lawn mowers, small power plants.
Many mechanics were engaged in the improvement of the internal combustion engine, and now the designs of the internal combustion engine are constantly becoming more complex. The first gas-fired internal combustion engine was invented in 1860 by the French engineer Etienne Lenoir. 16 years later, in 1876, the German mechanic Nikolaus Otto designed a more advanced four-stroke gas engine. And in the same year, Scotsman Dugald Clark tested the first successful two-stroke internal combustion engine.
What is the difference between two-stroke and four-stroke engines
The two-stroke engine gets its name because it has two strokes. The working cycle in the cylinder takes place in one revolution of the crankshaft, that is, in two piston strokes:
- 1 stroke - compression stroke,
- 2 stroke - called a working stroke.
A two-stroke engine is powered not by pure gasoline, but by its mixture with oil, usually this mixture is in certain proportions for different engine models. The cylinder sliding surfaces are lubricated by those parts of the oil that are in the gasoline. In some engine models, oil is additionally pumped into the bearings.
The principle of operation of a four-stroke engine is arranged in 4 strokes.
What happens when you press the gas pedal? The gas pedal controls the valve through which gasoline flows. Gasoline is mixed with air and sprayed. The camshaft opens the intake valve.
1 cycle. Inlet. In the first stroke, the engine piston goes down from top dead center. At the same time, the intake valve opens and fuel starts to be sucked in - a fuel-air mixture. The piston reaches the bottom dead center - the intake valve closes.
2 clock. Compression. On the second stroke, the piston goes up. The air-fuel mixture is compressed and ignition occurs.
3 clock. Working piston stroke. Just as in a two-stroke engine, the ignited mixture expands, and the gas that forms during combustion begins to push the piston down. The engine starts to run. When a portion of the fuel-air mixture completely burns out and the piston is at bottom dead center, the fourth stroke begins.
4 clock. Release. The exhaust valve opens and the piston begins its upward movement, displacing the exhaust gases, expelling them into the exhaust pipe.
Which engine is more powerful
A two-stroke engine with the same displacement and at the same speed has a greater power of about 1.5 - 1.7 times. How is this achieved?
A two-stroke engine at the same crankshaft speed has twice the number of working strokes than a four-stroke engine. The four-stroke engine takes time to purge. Compared to a two-stroke, it has two extra bars that are wasting time. It turns out that it has only one working stroke for two crankshaft revolutions. Therefore, it lags behind in power.
Pros and cons of internal combustion engines
- The two-stroke engine is simpler in design and weighs less. At 15 horsepower, the two-stroke engine weighs 36 kg, while the four-stroke engine weighs about 10 kg more.
- The designs of four-stroke engines are more complex and take longer to manufacture.
- Four-stroke motors are more expensive. A two-stroke engine is cheaper than a four-stroke engine in most cases.
- The two-stroke engine can be transported in any position and is easy to install.
- The fuel consumption of a two-stroke engine is approximately one and a half times higher with the same horsepower of the engine.
- Compared to a four-stroke, a two-stroke engine requires less maintenance.
- It will be cheaper to repair a two-stroke engine.
Advantages of a four-stroke engine:
- A four-stroke engine, when run at full power, is quieter than a two-stroke engine.
- It has a smoother ride.
- It is more economical. There is less vibration and smoke from it.
Which motor is best for a scooter
A two-stroke engine has significantly fewer parts. There is no camshaft, its drive mechanism, as well as a gas distribution valve. He has a simple carburetor, the same simple ignition and engine start system. He is not picky about the quality of the fuel. It is simple and straightforward. Therefore, such motors are often equipped with a field repair kit.
There is no forced lubrication system in two-stroke engines, including an oil pump and an oil filter. All this lightens the weight of the motor. Motors for small boats weigh 13-16 kg. Therefore, two-stroke models have a great advantage if you plan to buy a mobile kit that needs to be carried in any position.
Cons of two-stroke motors:
- A two-stroke engine needs a gas-oil mixture to work. With a consumption of 50 liters of gasoline, on average one liter of oil needs to be purchased.
- Two-stroke engines have a pungent smoke outlet.
- It makes a lot of noise during operation.
- He has more fuel consumption. About 30-50% more fuel is needed than four-stroke engines to operate.
Every year they are gaining popularity and more and more often you can find four-stroke engines on the reservoirs. The four-stroke engine is more complex because it has a camshaft, valves and a closed lubrication system. Four-stroke motors are more economical. This is their main plus. It is important that there is no need to add oil to the four-stroke engine in gasoline. This also translates into cost savings. It often requires only one oil change for the entire season.
A big plus of the four-stroke is stable quiet operation at low revs. The exhaust of such a motor is smokeless and does less harm to the environment. This has been confirmed by many tests and tests. The new four-stroke models have electronic fuel injection, which makes them even more efficient. In general, four-stroke engines have a higher resource. This is true if the engine is used commercially.
If we talk about the shortcomings, then there remains the need to regularly replace the filters, and also have to experience some inconvenience when transporting motors associated with the presence of oil in the engine crankcase.
From all that has been said, we can conclude that it is more profitable to use four-stroke motors. With a small example, we will see if this is so.
When using a two-stroke engine for a season, gasoline in the amount of 750 liters, grade Ai-92, purchased at 40 rubles, will require 30 thousand rubles. In a four-stroke engine, gasoline savings are large - about 40% less money will be needed, only 12 thousand rubles will be required for the season. For example, a two-stroke engine costs 160 thousand rubles, and its four-stroke analogue costs 270 thousand rubles. The difference in price is 110 thousand rubles.
30 thousand rubles. - 12 thousand rubles. = 18 thousand rubles.
110 thousand rubles / 18 thousand rubles per year = 6, 1 years
If we take into account the high oil consumption of two-stroke engines, then we can say that the payback in using four-stroke engines to the level of two-stroke engines will occur in 5 years.
But there is one more important unaccounted point. According to marketers, the resource of a four-stroke engine will last for more than one decade. Therefore, if possible, purchase a four-stroke engine - enjoy pleasant engine operation, ecology, and durability.
