The four-stroke engines are so called because the cylinder moves in four repeated cycles.

The main part of a combustion engine is the cylinder. And it is that it takes place the burning of fuel and processing of thermo-chemical energy into mechanical.

Each cylinder is composed of a piston that moves inside a metal cylinder to another shirt or jacket of the cylinder, thus transmitting the motion through a crank arm or the rod.

Working together usually two valves, one on admission and a depletion in sync as a cylinder, allowing it to run the four courses below:

Admission:

The piston is initially at the highest. The admission valve is opened. The piston descends and the air-fuel mixture enters the cylinder. In the case of diesel engines just enter the air at that time.

Compression:

The admission valve is closed and the cylinder rises, compressing the air-fuel mixture. In the case of diesel engines, only air is compressed, but a compression rate much higher.

Explosion:

This is the only active cycle of the engine. All mechanical energy is generated here. With the valves closed the spark plug generates a spark with enough power to burn the fuel-air mixture compressed in the cylinder. Because the rate of compression of the mixture, the burning takes place with great violence (explosion), creating great energy, pushing the cylinder down.

I enter the scene of the most important settings of the engine which is the point of ignition from the ignition of the electric candle burning itself and there is a slight delay.

If the ignition was generated at the point of maximum increase (or neutral Superior - SMP), the generation of energy occurs with the cylinder already in decline, which would cause a loss of power. To this point the engine is set a few degrees in advance of the SMP in order to achieve the maximum performance possible, which occurs without pre-detonation and consequent "hit the pin."

Exhaustion:

The piston is initially at the lowest. The exhaust valve is opened. The piston goes up and the gases from the burning of the air-fuel left by the exhaust pipe.
In parallel to all the cylinders several components provide the environment necessary for the operation of the engine.

By clicking on each of the four stroke engine is two turns of the crankshaft crank or turn around for each of the times. The crankshaft converts the linear motion of pistons into rotational motion, which is ideal for use in motor vehicles due to the ease of transmission of this type of movement to the wheels.