How Cars Work Part 1: Engine
When teaching Driving Lessons in Wakefield and Dewsbury, I often get asked how the engine or other components work. This page should help to make sense of what’s going on under the bonnet.
The process of how a car works is fairly simple, when you turn the key:
The car battery powers up then
Turns starter motor, which then
Turns the crankshaft, which then
Starts the pistons moving then
With the pistons moving the petrol/diesel ignites and then ticks over
Air gets drawn into the engine through an air filter
The air filter removes dust from the air
The clean air is drawn into a chamber where fuel is added
This fuel and air mixture is stored in the chamber
The driver presses the gas pedal
The intake valve is opened
The fuel and air mixture passes through the inlet manifold and is distributed, through inlet valves, into the cylinders.
A camshaft controls the opening and closing of the valves.
The distributor or engine management makes the spark plugs spark, which ignites the fuel-air mixture.
The resulting explosion forces the piston down which in turn causes the crankshaft to rotate.
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Intake stroke – intake (fuel) valve opens and the piston moves down drawing the fuel-air mix to enter the cylinder.
Compression stroke – the piston moves upwards. This compresses the fuel-air mixture. The compression makes the fuel-air mixture explode with greater force.
Power cycle – spark from a spark plug ignites the fuel-air mixture. The explosion forces the piston down the cylinder transferring power to the crankshaft.
Exhaust cycle – The exhaust valve opens as the piston moves back to the top of the cylinder forcing the exhaust fumes out.
Each piston is attached to the crankshaft, As the pistons are forced up and down the crankshaft rotates, which after sending the power through the gearbox, turns the wheels. The majority of cars have four cylinders and as many as sixteen. The more the gas peddle is pressed the more fuel-air mixture is allowed into the engine raising the revs and generating more power.
What Are Rev’s (RPM)? – The cycle explained above repeats itself thousands of times a minute. These repetitions are more commonly known as Revs or RPM. A rev counter tells you how many thousand times per minute the cycle is repeated.
Makes driving it seem a little less complicated.