Engines
Car engines are needed to make the vehicle run. Most car engines these days work by four-stroke internal combustion system. The reason for this is that there are four main stages in converting the fuel in the engine into a force that can move the car. The four stroke cycle is also referred to sometimes as the Otto cycle, named after the man (Nikolaus Otto) who invented it in 1867. This cycle occurs in each cylinder of the engine.
The Stages of the Four Stroke Combustion Cycle
The Intake Stroke
In this stage the intake valve opens allowing air to mix with the gasoline inside the engine. The Piston at the top of the cylinder, moves down in order to let this happen and allow in as much of a mixture as possible. The intake valve then closes which shuts in the mixture.
Compression
The piston now moves upwards to compress the mixture of gasoline and air together. (Compressing the mixture will make the energy released much more powerful.) The compression ratio for a diesel engine is 20:1 whereas it is 8 to 10:1 for a petrol engine.
Combustion
The moment the piston reaches the top of the cylinder, a spark is released to ignite the mixture by the Spark Plug. As a result of this, the cylinder bursts driving down the piston, turning the crankshaft and powering the car.
Exhaust Stroke
This is the final stroke in which the exhaust valve is opened and the burned ash from the blast is lead out of the cylinder into the tail pipe. This happens as the piston moves back to the top. This process is then continuously repeated.
Engine Types
There are many different types of engines available. They vary in size and cylinder arrangement. The engine size depends mainly upon the number of cylinders and the displacement each one produces. For example: A car with an engine containing 6 cylinders each with a displacement of 500cc/half a litre, will be a 3 litre engine. (This was calculated by multiplying the number of cylinders by the displacement .
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