An Investigation: How Car Engines Work.
If you summarize car engines, they operate very simply. There are four main functions of operation: intake, compression, combustion, and exhaust. These four factors are the most critical parts to a car engine, as they make the engine run, and allow the car to move. Gasoline links these four functions together, but is used only in combustion. A flammable liquid like gasoline produces an enormous force when ignited, and gives the car engine the power to propel itself. Compression makes the explosion all the more powerful, creating more pressure in the area of combustion.
The four stages of an internal combustion engine are all tied together, because if one of the four stages are left out, combustion will be unsuccessful. The first of the four strokes is the intake stroke. This occurs whenever the piston draws fresh air into the combustion area from the open valves. As the crankshaft turns the connecting rod to push the piston up and down, the camshaft spins and pushes the valves into the combustion area, allowing fresh air in. As the fresh air enters, a tiny squirt of gasoline is sprayed into the cavity by means of fuel injection. The valves then close, and the piston starts its way back to the top of the cavity, where it compresses the air and fuel mixture, creating a large amount of pressure in the cavity. As the piston reaches the very top of its stroke, the spark plug ignites the cavity, and the piston is driven down by the force of the explosion. The force pushes the piston to the bottom of the stroke, spinning the crankshaft very quickly, and the power is made to propel the vehicle. The piston then begins is journey to the peak of its next stroke, forcing out all of the exhaust fumes created by the explosion. The exhaust is forced out through the exhaust valves, opposite to the intake valves. The exhaust then travels out of the engine, and into the air.