Tuesday, March 12, 2013
How does a car work?
A car consists of many thousands of individual parts. But what is really necessary to drive the car? A cigarette lighter, power windows or car radio? Without these you could still drive a car.
Let's look at cars created more than 100 years ago. These cars had engines and various parts such as gears, clutch and drive shaft to transfer power from the motor to the four wheels, brakes and steering. A seat was available as well, because no-one wanted to stand all the time. All these parts were hung on a frame, the body.
Automobiles are equipped with engines that work with gasoline or diesel. Diesel fuel is nothing more than heating oil, only with a few chemical additives, so the engine runs better. The core of the diesel engine is a cylinder block which is a two, three, four, five or six (sometimes more) cylinder. These cylinders move the piston.
At the top of the cylinder, the injection nozzle is mounted, through which the diesel fuel is injected at high pressure into the combustion chamber. The cylinder head has two valves, the intake valve and exhaust valve. The piston moves the cylinder to the bottom, so air comes in through the intake valve into the cylinder.
In the next phase, the piston moves upward and the air in the cylinder is compressed. What happened here, you may know from the bicycle. If you own an air pump and have quickly pumped air into a tire, the air pump can become warm. This is because air that is compressed is heated. Now the air in the cylinder is compressed and very strongly (to about the 30 to 50 times our atmospheric pressure) and heated thereby to a temperature of 700-900 °C
Now comes the diesel fuel through the injector into the cylinder, it ignites at these high temperatures and immediately explodes. The piston now pushes down. The combusted air-diesel mixture exits out the exhaust, so that fresh air can enter again.
With two-stroke engines, this happens while the piston moves down. For four-stroke engines, which uses air for further movement is pressed upwards, and then the piston moves down again and starts over again.
The various cylinders (two, three or more) are now connected in series, so that it comes one after another to explode the fuel. The piston is attached to bottom with the rod (left) on the crankshaft (bottom). This is offset by the movement of the pistons into rotary motion.