How does gasoline power cars?

Question

I assume the gasoline is burnt to power the engine, or does it contain a chemical which creates a reaction? What’s the whole process?

In: Technology

Answer 1

Certain chemicals have a great deal of energy, and when ignited, burn with oxygen in the air, creating a lot of heat and also waste exhaust fumes, which is the end product of the two substances burning. In the case of gasoline in an engine, it works like this:

– When the piston is all the way at the bottom, two valves open, and air and fuel are injected into the cylinder. These valves then close shut so the piston cylinder is sealed.
– The piston, which is already moving up and down, starts to move all the way back up. This means that the air-fuel mix is compressed to a very high pressure, which makes the explosion more powerful.
– When it reaches the top and the mixture is at it’s maximum pressure, the sparkplug creates a spark that ignites the fuel and air, causing a huge explosion in the cylinder, which immediately forces the piston all the way back down with a great deal of force.

– Forcing this piston down turns the crankshaft, which turns the wheels.

– As it reaches the bottom again, the valves open to let exhaust gasses out, so the chamber is empty, and air and fuel back in to start the process again.

The entire process means that for the engine to work, the engine already needs to be in motion, because how else is the piston going to move all the way back up? This is why cars have batteries. An electric motor makes the pistons turn a few times to kickstart the process.

So, in short, it’s taking the chemical energy that’s inside gasoline, and releasing it in a quick chemical reaction by igniting it, causing it to burn and release energy, which we then turn into mechanical energy with a fast-moving piston.