How do cars work?
Like an inquisitive 6 year old I was curious about how cars work. I mean I get in and drive my car every day. I know what all (ok most) of the pedals, levers, buttons do but how does the car actually work? How do these series of actions I take daily as a driver result in a four-wheeled piece of tin moving forward and backwards? I set about to find the answer to the question How do cars work? It was more complicated than I originally thought. Each collective of components works independently but feeds into one another. I’ll explain more in this article starting with……
How does a car engine work?
In short, an engine works via an internal combustion engine. Huh?! Yes, that was my response too. Basically, the fuel and the air inside the engine combust (burn) to create energy. The energy moves the pistons to move the car. Simples!
The engine is made up of several parts I’ll give you a quick round-up of the main bits and what they do.
The internal combustion happens in the combustion chamber.
The Engine Block
The engine block houses a series of cylinders that are cast into it. The more cylinders the car has the more powerful the engine. This is why some cars are referred to as V6 or V8 engines. When an engine has more than four cylinders, they are divided into two engine blocks. This layout makes the engine look like a “V.” A V-shaped engine with six cylinders = V6 engine. A V-shaped engine with eight cylinders = V8. In addition to the cylinders, other ducts and passageways are built into the block that allows for oil and coolant to flow to different parts of the engine.
There are two types of valves in a vehicle, an intake valve and an outtake valve. Intake valves draw in air and fuel to the combustion chamber which is needed to power the engine. Outtake valves allow the waste fumes created after the combustion to escape the chamber via the exhaust.
There are three different types of fuel injector. Direct fuel injection, Ported fuel injection, or Throttle body fuel injection. These are all designed to inject the fuel for combustion. A direct fuel injection shoots the right amount of fuel at precisely the right time into the chamber and each cylinder has its own fuel injector. The Ported fuel injection sends the fuel to outside of the valve where the right amount is allowed into the combustion chamber by the valve. Throttle body fuel injection has just one injector. The fuel mixes with the air in a part called the throttle body and it’s then dispersed into the cylinders via the intake valves.
How does car steering work?
We all know that when you turn the wheel the car wheels move in that direction to steer the car. If you are a driver and don’t know this I am going to be worried. But what about the mechanics behind this? How does the steering wheel tell the tyres which way to turn? There are two common types of steering system and both are quite clever ‘behind the scenes’.
Did you know?
For a car to turn smoothly, each wheel must follow a different circle. Since the inside wheel is following a circle with a smaller radius, it is actually making a tighter turn than the outside wheel. Seems simple now you know!
Rack and Pinion steering
This type of steering is becoming the most common system used by manufacturers in cars and SUV’s. The mechanism is enclosed in a metal tube with each end of the rack extending from both ends of the metal tube and tie rods connecting to each end of the rack. The pinion gear is attached to the steering shaft. The steering shaft is the piece of metal which goes from the steering wheel column and feeds down into the mechanism. When the steering wheel turns it spins the gear. This moves the rack and the tie rod at each end connects to the steering arm and moves the wheels.
The rack-and-pinion gearset does two things:
- It converts the rotational motion of the steering wheel into the linear motion needed to turn the wheels.
- It provides a gear reduction, making it easier to turn the wheels.
The recirculating-ball steering gear contains a worm gear. The worm gear is a piece of metal with a hole in and teeth cut into the outside. The teeth engage a gear that moves a shaft which is called the pitman arm. FYI the pitman arm runs off of the steering column and into the wheel base. The steering wheel connects to a rod which threads through the hole in the worm gear. It’s similar to a bolt but instead of twisting further into the block like a regular bolt it is held fixed. When it spins it moves the block which in turn moves the gear and this turns the wheels. Phew!
The threads in the system are filled with ball bearings that recirculate through the gear as it turns, hence the name. These ball bearings reduce friction in the gear which minimises wear and tear. But handily, they also stop the teeth in the gear coming out of contact with each other which would lead the steering to feel loose and not perform at its best.
How do gears work?
Each time you change gear there is a lot going on behind the scenes. When you press down the clutch the shaft that comes from the engine through to the clutch disconnects from the transmission. This is so the engine can still run even if the car is stationary. When the clutch pedal is released the engine and shaft re-connect to engage the gear again.
When you put the car in gear
So you put down the clutch and move the car into first gear. You accelerate and move away. When you move the gear stick into position this moves and internal gear selection fork. The gear selection fork is on a shaft leading to a series of cogs. When the gear selection fork moves it shifts the collar cog in between two larger cogs which move freely along the shaft. The collar cog is the controlling factor, depending on the gear selected it will connect with the cogs either side to slow them down. The cog speed affects another two large cogs on another shaft which leads into the engine.
A car is a complicated machine with lots of clever parts and features. All of them work independently and simultaneously to make the vehicle perform as we want it to. Every little action we take as drivers to make the car move forward, backwards, round corners and even braking is followed by a series of levers, cogs and shafts all spinning, moving and working away to make the car do as it’s told.
The importance of servicing and maintaining all of these parts is easy to see when you understand the complexities of an engine more because just one small fault in a cog of this big bad machine can have a dramatic knock-on effect on the rest of the car. So, make sure you check when your car is next due for a service and get it checked in plenty of time. Make your regular vehicle checks at home which include things like checking screen wash and oil to help keep everything running smoothly in between garage checks.
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