2-STROKE VS 4-STROKE ENGINES

You may have noticed I’m fond of cars and engines. That’s also why I’d like to be an engineer one day. Today I’m going to describe the most common types of car engines. You may have heard the terms 2 stroke and 4 stroke engines before, but do you really know all of the differences in their operation? I hope my post and the video below may help if you don't. 

The combustion engines are the most common type of engine with regard to means of transport like motorcycles, cars, busses and trucks but they are used also for small power tools like lawn mowers and chainsaws. In one of my articles in the blog I mentioned how they work but these two types have a small difference that change how they are made and used. How it works? A piston connected to the crankshaft by means of a connecting rod, flows up and down in a cylinder thanks to the force generated by the explosions of a mixture of air and gasoline. The connecting rod has the task of transforming the piston motion into a rotary motion.  But let’s talk about the differences about 2-stroke and 4-stroke engines.

THE 2-STROKE ENGINE

It is simply and lite and it has a small cilindrate. The first difference is that it needs of a mixture of oil and gasoline fot the lubrification. But the substantial difference is that in a single cycle, the piston aspirates, the explosion take place (when the piston is up) and then the gases are expelled.

A carburettor, sends the fuel in the carter under the piston, while it is up. When the explosion takes place , the piston flows down and pushes the fuel in the combustion chamber, sending the gases out through the muffler. This engine is used also for scooters or motorcycles of small displacements. In poor words, one cycle corresponds to a burst.

THE 4-STROKE ENGINE

The principle of this type of engine is the same as the 2-stroke engine. The first difference is how it is fuelled. We don’t need to put oil in the gasoline, and the carburetion can be done by an injector and valves. The piston flows down while the intake valve opens. The fuel enter in the cylinder and when the piston turn up, the spark of a candle detonates the gasoline pushing it down again. While it flows up expels the exhaust valve opens and the gasses are expelled and while the piston flows down the cycle start again. In poor words, two cycles correspond to one burst. The crankshaft is lubricated with oil put in the oil cup.

So the 4-stroke engine works in 4 steps: intake, compression, combustion and exhaust. It is used for motorcycle of big displacement, buses, cars and trucks.

The 4-stroke engine is more reliable and consumes and pollutes less. At the same displacement, the power of a 2-stroke engine is double compared to the 4-stroke engine because more explosions occur. 4-stroke engines can be fuelled with gasoline, GPL, and diesel while the 2 stroke engine can be fuelled only with a mixture of gasoline and oil.

DAVID