Have you ever been cruising down the road wondering how the engine in your car works? How the car can take a liquid such as gasoline and convert it into movement, propelling you down the road at speeds triple of what a horse could gallop at. Well, there is a detailed process of moving components that allow that to happen. If you look under the hood of your car you’re likely to have a piston driven internal combustion engine, although there are other engines such as rotary engines, hydrogen fuel cell engines, and electric engines. These piston engines are made up of anywhere from 1 to 16 cylinders although your car most likely has 4, 6, or 8 cylinders, in a straight, flat, or V shaped configuration. These cylinders are drilled into a steel engine block to make way for a plunger like device called a piston. This piston is designed to tightly fit in the cylinder to maximize power. The piston is driven up and down with the help of the rotation of the crankshaft. The four strokes of the piston are as follows
- Intake- This is where the piston starts at the top of its stroke and goes down, with the intake valve letting in the fuel air mixture into the cylinder to start this process
- Compression- The piston starts here at the bottom of its stroke and heads up pushing the molecules of oxygen and octane closer together optimizing the mixture for combustion. As the piston almost reaches the top of its stroke the spark plug sends out a little bolt of electricity that will ignite the fuel once the piston reaches the top of its stroke
- Power- BOOM! This is where the fuel air mixture is ignited and creates the power necessary to drive the piston back down and rotate the camshaft for the other pistons to continue their role in the power making process
- Exhaust- Finally, after the oxygen and octane is converted into carbon dioxide and water vapor, the exhaust valve is opened where the gas in the cylinder rushes out to be propelled out of the exhaust. The cylinder during all of this rises to the top ready to start the process all over again
All of this power from combustion is sent to the cars transmission which controls how much power is sent to the drive wheels through the use of gears controlled either manually with a clutch or automatically with a torque converter and the cars on board computer. The correct amount of power is sent to spin the drive shaft which then spins the differential to allow the drive wheels to be turned at different speeds. For example, when you go around a corner the outside wheels must turn faster than the inside wheels because they have a greater distance to travel. As you can see the process to combust liquid gasoline and transfer that to the drive wheels is quite complex and is truly a feat of engineering that makes you admire the fact that some of these engines are reliably making 600+ hp. And to think all of this is possible because of the power of machines!