How really normal stuff works: Cars

 
 

Farouq Manji explains the logic behind the humble automobile

Strictly speaking, it is important to understand from the off that cars are female. They are strikingly similar to the fairer sex: they require regular maintenance and care, are often temperamental, and it seems newer models are increasingly, mind-blowingly complicated. Plus, they can cost a fortune.
This is perhaps why men form such amorous bonds with our cars. Unlike the opposite sex, we eventually figure out how cars work, and a beautiful, storybook romance is born. There exists only one key for your car’s ignition, so to speak.
Women of course form a strong camaraderie with their cars as well, but like two powerful, deadly organisms forming an alliance, there is a loveless agreement between them: to get to the shopping sale first, leaving carnage in their wake.
That said, shouldn’t we understand our friend/lover better? What exactly happens under the hood of your car? There are several systems that work together to make a car go. The first, and often most mysterious, is the motor.
Imagine you put a lit firecracker into an empty Pringles jar, and shoved an empty Coke can on top. When the firecracker blows, the can would shoot out, and you’d probably spend some time in A&E. This is the general principle on which a motor works.

“Imagine you put a lit firecracker into an empty Pringles jar, and shoved an empty Coke can on top. When the firecracker blows, the can would shoot out, and you’d probably spend some time in A&E. This is the general principle on which a motor works”

In the motor block, a cylinder (the Pringles jar) exists with a piston inside (can). When a mixture of air and gasoline are ignited under the piston, it fires upward. A rod attached to the top of the piston spins a shaft, which eventually spins the wheels. Each piston does this several times a second.
Now imagine if you had four cylinders in a row: the motor would have four times as much power! This is why we have 4, 6, and even 8 cylinder motors. A V8 is an 8-cylinder motor where the cylinders stick out of the block in a V shape. More cylinders mean more power. And men never over-compensate – there is no such thing. Quite simple, really.
The complicated part is the timing of when each cylinder fires. If they all fired at once, there would be a huge force on the shaft, but then as they all reset for another fire, the shaft would slow down. The result would be a slooow, fast!, sloooow, fast! motion of the car, over and over, on your way to the A&E with an aluminium Coke can lodged in your skull.
To make things smooth, each piston fires one at a time, in a cycle. The higher you rev the motor, the faster each piston fires, and the faster the cycle – thus increasing your rounds per minute, i.e. your RPM.
So now we have this spinning shaft: how does this translate to power at the wheels? It is transmitted through the transmission.
The transmission essentially delivers the power of the motor to the wheels, but does it in a smart way. Imagine, if you will, a 40-stone Hilary Duff. She could probably push a dumptruck up a hill, but it would be impossible for her to run over 20 km/h. The first gear of your transmission acts the same way – from a standstill, you need to move your very heavy car forward; this is called torque. But as a result, you sacrifice top speed.
As you progress through the gears, your transmission acts less like Duff, and more like a long distance runner – a much higher top speed, but utterly unable to push a heavy object – so once you reach fifth gear, you can go very fast, but you can’t accelerate very quickly (as you could in first). This is the reason you can’t start your car in fifth gear!
This brings us to the clutch, which plays an integral role in the relationship between motor and transmission.  If you were to engage the motor straight into the transmission, you would be jamming an object travelling at over 2000 RPM into a stationary object. The engine would simply seize and die. This is actually what happens when you stall your car.
Instead, the clutch acts as a method of ‘easing’ the motor into the transmission. When the clutch is engaged, the motor and transmission are completely apart. As you let go of the clutch, the two slowly come together, but timing is everything. If you let go too quickly, the motor engages with the transmission too fast, and you stall.
When you want to switch gears, you activate the clutch – which pulls apart the motor and transmission – then change the gears, and release the clutch again, letting the motor re-engage. This is also why a clutch wears out over time: it absorbs the power of the motor so that the engagement of the motor and transmission is more gradual, and as a result takes quite a beating.
Now let’s revisit the motor. Although its primary role is to transfer power to the wheels, it has a lot of other roles as well. Among these is providing power to the fan belt and alternator.
The alternator is a particularly important aspect of the engine. When it spins, it provides electricity to the car for the lights and radio, but also for the spark plugs in the motor. Spark plugs are what ‘spark’ the ignition of fuel to drive the piston. Without it, the car, and your tunes, will die.
Since the motor is a constantly moving machine composed of metal, it becomes very hot due to friction. To remedy this, oil is used to lubricate the moving parts. Under such intense stress, bits of metal from the motor inevitably break off. The oil also breaks down, becoming less effective. This is why oil is changed regularly.
To keep the motor from overheating, water or coolant is also run throughout the motor to absorb heat from its moving parts. This superheated fluid is sent to the ‘radiator’ to radiate the heat away, which is smartly placed in front of the car so when travelling forward, thus allowing wind can help scatter the heat.
This effect is amplified by a large fan behind the radiator which is often driven by the motor, via a belt. The squealing you hear from old cars is often from the fan belt, the alternator belt, or the orange high-heeled Freshers trying to run off the road.
And of course, some cars are prettier than others when it comes to the exterior. ‘Accessories’ such as spoilers (hair), exhaust tips (mini-skirts), rims (high-heels), and dice (earrings) all help to glamourise your baby. But at the end of the day, the knowledgeable will realise it’s what’s beneath the hood that counts – and partly the junk in your trunk.

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