Diesel how does it work

Fuel filler: A nozzle from a fuel dispenser attaches to the receptacle on the vehicle to fill the tank. Fuel line: A metal tube or flexible hose or a combination of these transfers fuel from the tank to the engine's fuel injection system. Fuel pump: A pump that transfers fuel from the tank to the engine's fuel injection system via the fuel line. Fuel tank diesel : Stores fuel on board the vehicle until it's needed to power the engine. Internal combustion engine compression-ignited : In this configuration, fuel is injected into the combustion chamber and ignited by the high temperature achieved when a gas is greatly compressed.

This means that the combustion chamber as a whole is irregularly shaped, causing combustion problems and hampering efficiency. A direct injection engine does not have a swirl chamber into which the fuel is injected - the fuel goes straight into the combustion chamber instead.

Engineers have to pay very careful attention to the design of the combustion chamber in the piston crown to ensure that it creates enough turbulence. A diesel engine is not throttled like a petrol engine, so the amount of air sucked in at any particular engine speed is always the same. Engine speed is regulated purely by the amount of fuel squirted into the combustion chamber - with more fuel in the chamber, combustion is fiercer and more power is produced. The accelerator pedal is connected to the metering unit of the engine's injection system rather than to the throttle butterfly as with a petrol engine.

The engine then only has to use a small amount of fuel before it comes to a halt. In fact, diesel engines come to rest more quickly than petrol engines because the much higher compression has a greater slowing-down effect on the engine.

As with petrol engines, diesel engines are started by being turned with an electric motor , which begins the compression-ignition cycle. When cold, however, diesel engines are difficult to start, simply because. To get around the problem, manufacturers fit glow plugs. These are small electric heaters, powered from the car's battery , which are switched on a few seconds before attempting to start the engine.

The fuel used in diesel engines is very different from petrol. It is slightly less refined, resulting in a heavier, more viscous and less volatile liquid. These physical characteristics often lead to it being referred to as 'diesel oil' or 'fuel oil'. On diesel pumps on garage forecourts it is often called 'derv', short for diesel-engined road vehicles. Diesel fuel can begin to stiffen slightly or even solidify in very cold weather. This is compounded by the fact that it can absorb very small quantities of water, which may freeze.

All fuels absorb tiny amounts of water from the atmosphere and leakage into underground storage tanks is quite common. Diesel fuel can handle a water content of up to 50 or 60 parts in a million without problems—to put this into perspective this is about a quarter of a mug-full of water for every ten gallons of fuel.

Any freezing or 'waxing' can block fuel lines and injectors and prevent the engine from running. Diesel engines use direct fuel injection i. A diesel engine compresses only air, so the compression ratio can be much higher. The higher the compression ratio, the more power generated. Diesel fuel injectors, unlike gasoline injectors, must be able to withstand the temperature and pressure inside the cylinder and still deliver the fuel in a fine mist.

To ensure that the mist is evenly distributed throughout the cylinder, some diesel engines are equipped with special induction valves or pre-combustion chambers. Newer diesel engines are equipped with high-pressure common rail fuel systems.

See Diesel Fuel System Basics for more information on this type of fuel system. Diesel engines may be equipped with a glow plug. When a diesel engine is cold, the compression process may not raise the air temperature high enough to ignite the fuel.

The glow plug is an electrically heated wire that facilitates fuel ignition when the engine is cold.