How Cars Work

There are two types of engine

1. Internal combustion engine( combustion of fuel takes place internally)
2.External combustion engine( combustion of fuel takes place externally)

Currently the easiest way to create motion from chemical energy of fuel is to burn the fuel internally or inside an engine. Therefore, a car engine is definitely an internal combustion engine.

How Cars Work The Workings Of A Car Explained

The process by which a car works is a lot simpler than you may think.

• When a driver turns a key in the ignition
• The car battery powers up
• Sending power to the starter motor, which
• Turns the crankshaft, which
• Gets the pistons moving
• With the pistons moving the engine fires up and ticks over
• A fan draws air into the engine via an air filter
• The cleaned air is drawn into a chamber where fuel is added
• This air-fuel mix is stored in the chamber
• When driver presses the accelerator pedal, the throttle valve is opened which regulate the air-fuel mixture supply.
• The air-fuel mix passes through an intake manifold and is distributed into the cylinders through intake valves. The camshaft controls the opening and closing of the valves.
• The distributor makes the spark plugs spark, which ignites the fuel-air mix. The resulting explosion forces a piston to move down which in turn causes the crankshaft to rotate.

What happens in the cylinders is the magic that gives power and motion to the car wheels. Most car engines use a four-stroke combustion cycle. This cycle starts with piston at the top of the cylinder. Then:

Intake stroke: intake valve opens and the piston moves down allowing the fuel-air mix to enter the open space.

Compression stroke: the piston moves upwards. This compresses the fuel-air mix by forcing it into a smaller space. Compression makes the fuel-air mix explode with greater force.

Power cycle: spark from a spark plug ignites the fuel-air mix. The explosion forces the piston down the cylinder.

Exhaust cycle: the exhaust valve opens and the piston moves back to the top of the cylinder which forces the exhaust fumes out.

The bottom of each piston is attached to the crankshaft.

As the pistons are forced up and down they rotate the crankshaft, which after sending the power through the transmission, turns wheels.

Most cars have at least four cylinders. More powerful cars have more. For example a V6 has six cylinders and a V8 has eight.

The harder a driver presses on the accelerator pedal the more fuel-air mix is passed into the cylinders and the more power is produced.

What Are Revolutions Per Minute?
The four-stroke cycle repeats itself thousands of time a minute. These repetitions are more commonly known as Revs.

A rev counter tells you how many thousand times per minute the cycle is repeated.

The Transmission

It controls the power contained in the crankshaft before it goes to the wheels and allows a driver to control the speed/power of a car by providing different speed/power ratios known as gears.

So first gear gives plenty of power but little speed whereas fifth gear provides little power but plenty of speed.

The crankshaft only connects to the transmission when the car is in gear and the clutch is engaged. If you press down on the clutch the crankshaft disconnects from the transmission.

The transmission is connected to the output shaft, which is connected to the axles, which are connected to the wheels. When the transmission rotates the output shaft this turns the axles, which in turn rotate the wheels.

Other Car Engine Components

Carburetor: T­he goal of a carburetor is to mix just the right amount of gasoline with air so that the engine runs properly. 

If there is not enough fuel mixed with the air, the engine "runs lean" and either will not run or potentially damages the engine. 

If there is too much fuel mixed with the air, the engine "runs rich" and either will not run (it floods), runs very smoky, runs poorly (bogs down, stalls easily), or at the very least wastes fuel.

Intake manifold: is the part of an engine that supplies the fuel-air mixture to the cylinders.

 

Camshaft: controls the opening and closing of the intake and exhaust valves.

Exhaust System: once the fuel-air mix has been burnt the remaining gas enters the exhaust system and is expelled from the car. If a catalytic converter is present the exhaust gas passes through it and any unused fuel and other certain chemicals are removed. 

Alternator: turns mechanical energy into electrical energy. This energy powers a car's electrics, from lights to wipers. It also recharges the car battery. A belt that rotates once the engine is on powers it.

Brakes: cars use either drum or disc brakes. Disc brakes use a calliper to press onto the disc of the wheel in order to slow the wheel down. Drum brakes work on the same principle however a drum brake presses against the inside of the drum. 

Cooling System: car engines produce a lot of heat. This heat needs to be controlled. To do this water is pumped through passages that surround the cylinders and then through the radiators to cool down.

Coolant is a fluid which flows through or around a device to prevent its overheating, transferring the heat to other devices that use or dissipate it

Radiators are heat exchangers used for cooling internal combustion engines, consisting of a series of tubes through which water is circulated to transfer or radiate heat into the surrounding space.

Thermostat: a device that maintains a system at a desired constant temperature automatically or signals a change in temperature for manual adjustment.

Distributor: distributes the spark to the right cylinder and at the right time. 

Handbrake: this is a separate system from the foot brake and is connected by a cable to the two rear wheels.

Head Gasket: the cylinder head (a block that seals all the tops of the cylinders) and the engine block (which contains the main bodies of the cylinders) are separate components that need to fit seamlessly together. The head gasket is a piece of metal that sits between them and connects them.

Oil: a car engine consists of many moving parts. Oil lubricates these parts and allows them to move smoothly. In most car engines oil is pumped out of the oil pan through a filter that removes any dirt and then is squirted under high pressure onto the bearings and cylinder walls. The oil then trickles down to the sump where the process starts over.

Regulator: regulates the amount of energy in the alternator.

Suspension System: counteracts the effects of hitting bumps in the road. Without such a system a car would veer of course every time the tyres hit a bump or pothole. The system comprises of springs and shock absorbers. The springs absorb any of the energy released when the tyres roll over a bump and the shock absorbers absorb the energy from the springs. This keeps the main body of the car steady and stable. 

Shock Absorbers: also known as dampers, are fitted between the car's body and axle in order to prevent excessive rolling and bouncing of the car body during motion. 

Timing Belt: a belt connected to both the camshaft and crankshaft ensuring that they work in time with each other.

What is the difference between a Petrol and Diesel Engine?

In petrol engines fuel is mixed with air and then forced into the cylinders where the fuel-air mix is compressed by the pistons and ignited by spark plugs.

In a diesel engine the air is compressed before the fuel is added to it. When air is compressed it heats up. This means that when the fuel is added to the compressed air it is very hot and the fuel-air mix ignites automatically. So there are no spark plugs in a diesel engine as pressure is used to ignite the fuel-air mix.

How the charging system works

A car uses quite a lot of electricity to work the ignition and other electrical equipment.

If the power came from an ordinary battery, it would soon run down. So a car has a rechargeable battery and a charging system to keep it topped up.

The battery is charged by an alternator on modern cars, or by a dynamo on earlier ones. Both are types of generator, and are driven by a belt from the engine.

A warning light on the dashboard glows when the battery is not being adequately charged, - for example, when the engine stops.

There may also be an ammeter to show how much electricity is being generated, or a battery-condition indicator showing the battery's state of charge.

Source: Compilation of information from internet