Most of us have a car, and still more of us are aware of the concept of a car. But how do these cars move? What is the driving force behind these machines? Yes, you guessed it, the answer is the engine. It is an invention that has caused immense turmoil among environmentalists and caused the phrase “Curse you, planet destroyer!!!” to be uttered from the lips of many. It can be found at the front, in the middle, or at the back of a car, and have any number of cylinders. Most cars you see today are powered by an engine that uses a four stroke combustion cycle also referred to as the Otto cycle in honor of Nikolaus Otto, who invented it in 1867. The four strokes carried out by the engine are:
The piston starts at the top of the cylinder. As the intake valve opens, the piston moves down to let the engine intake a cylinder full of air and gasoline (or petrol). Only a tiny drop of fuel is needed to be mixed with the air for this to work. The piston then moves back up the cylinder compressing the air and fuel mixture. Compression makes the combustion more powerful. When the piston reaches the top of the cylinder, the spark plug emits a spark to ignite the fuel. The fuel charge in the cylinder combusts driving the piston down. When the piston hits the bottom of the cylinder, it is the exhaust valve’s turn to open and expel the exhaust from the engine and eventually from the car through the tail or exhaust pipe. This process happens very quickly and takes place in each cylinder of the car.