Cars have played and still play a significant part in our society. They are the most popular means of transportation in most of the world. Their advent has produced significant shifts in employment patterns, infrastructure, distribution of goods, and social connections.
They’ve had an especially profound impact on American culture and have been featured as centerpieces in music, books, and movies.
Despite this, most people think of their cars as tools that get them from point A to point B, and that would be an accurate definition. But how does it do that? If you’re reading this article, it probably means you’re curious to find out.
What makes a car move and get you from one place to another is its engine. So, how does the engine work?
A car engine, or more specifically, an internal combustion engine, works by using heat from burning fuel. It transforms the energy derived from that heat into torque – mechanical work. The torque turns the wheels, so the car moves.
Engines have these metal tubes called cylinders, and inside those cylinders, there are pistons that go up and down. The pistons are connected to a crankshaft via rods, so when they go up and down, they spin the crankshaft, similarly to how you move your legs up on down on the pedals of a bicycle and turn the gear they’re connected to, which moves the chain attached to the gear. This chain is attached to another gear at the rear wheel, so the bicycle moves forward.
The car’s crankshaft gets turned by these rods connected to the pistons, and in the process, it turns the wheels of the car.
Where Does the Engine’s Power Come From?
The pistons are propelled up and down by thousands of little controlled explosions that occur each minute as a result of combining fuel and oxygen and igniting the mixture. Combustion – also referred to as stroke – is the term used to describe each time the fuel ignites. These little explosions produce expanding gases and heat, which push the piston down.
Most internal combustion engines used in cars today are four-stroke engines. In these engines, the piston completes four separate strokes while turning the crankshaft. There’s the combustion stroke that pushes the piston down and three more – intake, compression, and exhaust.
To burn the fuel, engines need air or the oxygen in the air, to be more specific. To get oxygen, there are valves that open, and when the piston goes down in the cylinder, it draws in ambient air much like a syringe. The piston then reaches the bottom of the cylinder, and the valves close, so the cylinder is sealed. The piston goes back up, compressing the intake charge – this is what we call the compression stroke.
The fuel is fed to the engine, either injecting it directly into the cylinders during the compression stroke or it’s premixed with air during the intake stroke. In both cases, the mixture will be ignited through spark plugs when the piston is almost at the top.
When this mixture is ignited, it results in an expansion of hot burning gasses that push the piston down – the combustion stroke. This is the stroke that makes the wheels of the car turn. At the end of the combustion stroke, so when the piston reaches the bottom, exhaust valves open, allowing the combustion gases to get pumped out of the engine when the piston moves back up. These gases will then go through the car’s exhaust system and get evacuated at the back.