A gasoline engine produces movement when energy is created by gasoline being burned inside the engine. This is known as internal combustion. The various parts of the engine work together to produce this reaction and power a vehicle. Understanding how each portion of the engine contributes to the movement of your car will help you to understand how an engine works.
Under the hood of each vehicle is a series of cylinders. Depending on the model, there may be 4, 6, 8, or more cylinders. They can be arranged in a straight line, in a V, or horizontally opposed (flat), depending on what advantages the manufacturer is looking to give the specific engine. Inside each cylinder is a metal piston that moves up and down. The other parts of the engine work with the piston and cylinder to power the drive train.
- Spark Plug: When signaled by the ignition, the spark plugs release carefully timed sparks into the cylinder.
- Valves: Each cylinder is equipped with valves that can open to let air in and exhaust out. At the same time that the spark plugs fire, the valves allow a mixture of air and fuel to come into the cylinders, where the whole thing ignites.
- Pistons: The ignited air and fuel mixture cause pressure to build in the cylinder, which pushes on the piston and causes it to cycle through in an up and down motion.
- Connecting Rods: The pistons are attached to connecting rods, which are in turn connected to the crankshaft.
- Crankshaft: The crankshaft is turned in a circular motion when powered by the pistons and connecting rod. This puts the drive train in motion and makes the wheels turn, which makes your car go.
- Sump: Encases the crankshaft to collect and distribute oil to the moving parts of the engine.
Depending on the age and type of engine there may be additional components. One is a camshaft that is positioned above the valves and works to lift them. This system caused a little lag in the engine which reduced power and is not usually used in newer engines.
Making These Components Work Together
For an engine to run properly, the timing between the spark plugs, valves, and pistons must be exactly right. Any variance in any of the moving parts can cause the engine to lose power or to fail altogether. All of these parts require ample lubrication from engine oil to stay running smoothly. In addition, the temperature inside the engine must be controlled to produce exactly the right amount of power during each cycle. This is why we refer to anything that operates miraculously smoothly as “running like a well-oiled machine.”