The other name for a car engine is internal combustion engine; it is designed to make use of controlled explosions on smaller scale to generate power needed to operate the vehicle. Same engine is used in lawnmowers, motorcycles and other devices which use motors for their running. There have been a number of advancements to make better use of power and increase efficiency but still car engines are simple machines.
The car engines use four stroke combustion cycles, namely intake, compression, combustion and exhaust. These four steps are repeated in quick succession to generate power necessary for operation of a car and these four steps take part inside the car’s engine.
Imagine a windmill, this will give you a better idea about the car engine, its arms move with the force of wind and as they move they generate energy which is then used to move the heavy grinding stones or to produce energy.
The engine of car operates on the same principle but in winds place, it uses small controlled explosions to move the pistons of the engine and when the engine runs out of energy from the explosion another explosion takes place, this forces the piston to move again and this process goes on until needed.
A small metal rod attached to a connecting rod via a crankshaft is called a piston. When the engine is going through an intake cycle the piston moves down when intake valves open, to start the process. This gives chance to air and a small amount of gas to enter into the engine.
In the next cycle namely compression cycle opposite motion of piston occurs and this thins out the air and reduces the fuel. This helps in explosion as smaller the space will be, stronger the explosion will be. To ensure no energy is lost, an airtight seal on this space is held strongly.
When the cycle is on peak the spark plug comes into action releasing a spark that explodes the gasoline. This takes the piston down again steam engine model kit and if there is a mismatch in the time the explosion fails to take place.
The exhaust valve comes into action at the trough of the stroke to ensure no residues from waste gas are left inside the engine. At the base of the stroke, an exhaust valve unlocks so that the waste gas from the explosion can go away from the engine. The gas moves down with recurring explosions to the catalytic converter and muffler. The exhaust leaves the car through a tailpipe and air is filtered from the large pollutants before the process.
The speed of car depends on the speed of this cycle and its repetition, the piston moves faster when the driver injects large amounts of gas into the engine and this helps in the increased speed of cycle and hence faster speed of the car.