The engine is the system which produces the power to move the car.
It does so by burning a precise mixture of fuel and air,converting the fuel's stored energy into mechanical work,and delivering that mechanical work in a useful form.
Most engines are of reciprocating-piston design,and operate on the four-stroke cycle.
The combustion of the air/fuel mixture creates tremendous pressure in a closed space above a piston,forcing the piston downward in its cylinder,and translating the energy of combustion into a mechanical force.
The crankshaft converts each piston's motion into rotating motion,in much the same way that the up-and down motion of a person's legs rotates the pedals of a bicycle.
The power,transmitted in this rotary form, can then be used to move the car.
Intake Stroke 进气冲程
The piston while going down inside the cylinder creates low pressure.
The fresh air/fuel mixture rushes in because of the low pressure with the intake valve open.
When the piston goes down near the bottom of its travel the intake valve closes ,causing the cylinder sealed,fulled of air and vaporized fuel.