What Ignites The Fuel In A Diesel Engine

What Ignites The Fuel In A Diesel Engine – Posted on February 18, 2013 in Uncategorized. Tagged: diesel engine, four stroke engine, two stroke engine. Leave a comment

Diesel engine also known as compression ignition engine. It is an internal combustion engine that uses the heat of compression to initiate the ignition to burn fuel, which is drawn into the combustion chamber. This is in contrast to spark ignition engines such as gasoline engines (petrol engines) or gas engines (which use a gasoline fuel as opposed to gasoline), which use a spark plug to ignite an air-fuel mixture. The engine was developed by German inventor Rudolf Diesel in 1893.

What Ignites The Fuel In A Diesel Engine

What Ignites The Fuel In A Diesel Engine

The diesel engine has the highest thermal efficiency of any conventional internal or external combustion engine due to its very high compression ratio. Low-speed diesel engines (as used in ships and other applications where the overall weight of the engine is relatively unimportant) can have a thermal efficiency of more than 50%.

Diesel Fuel System Faults, How To Detect, Prevent And Cure Them?

Diesel engines are produced in two-stroke and four-stroke versions. They were originally used as a more efficient replacement for stationary steam engines.

Two-stroke diesel engine: The working of a two-stroke diesel engine is also similar to that of a two-stroke petrol engine. The advantages of the two-stroke compression engine when compared to the four-stroke compression engine are as follows

In the case of the two-stroke petrol engine, the fuel is too much because of short-circuit loss when both ports are open, but this is not the case with the two-stroke diesel engine, as the cylinder contains only air. Therefore it can be said that the two-stroke cycle is most suitable for CI operations

Four-stroke diesel engine: The working of this engine is similar to the petrol engine, expect as below

Kerosene In Diesel Engine Question

Intake/induction stroke: During this stroke only air is taken into the cylinder through the intake valves as the position moves from TDC to BDC.

Compression stroke: During this stroke the piston is made to move from BDC to TDC and compresses the air, which was previously drawn into the cylinder. At the end of the stroke, diesel is injected (sprayed at high pressure 100 bar and above) into the cylinder. And the burning process begins. Therefore, the engine is called a compression ignition engine.. Traditionally, diesel engines have always been seen as noisy, smelly and underpowered engines of little use except in trucks, taxis and vans. But as diesel engines and their injection system controls became more refined, the 1980s changed the situation. Almost 65,000 diesel cars were sold in the UK in 1985 (about 3.5 percent of the total number of cars sold), compared with just 5,380 in 1980.

Many diesel cars are based on existing petrol engine designs, but with key components strengthened to cope with the higher pressures involved. Fuel is supplied by an injection pump and metering unit, which are usually mounted on the side of the engine block. No electrical ignition system is required.

What Ignites The Fuel In A Diesel Engine

The main advantage of diesel engines over gasoline engines is their lower operating costs. This is partly a result of the greater efficiency of the high compression ratio diesel engine and partly due to the lower cost of diesel fuel – although the price difference varies so the advantage of driving a diesel car will be slightly reduced if you Live in a high. Service intervals are often more expensive, but many diesel models require more frequent oil changes than petrol.

Diesel Hybrid Engine: New Hyundai Diesel Runs On Gasoline

The main drawback of the diesel car is its lower performance compared to gasoline engines of equivalent capacity. One way around this problem is to simply increase the size of the engine, but this often results in a significant increase in weight. Some manufacturers add turbochargers to their engines to make them competitive in terms of performance; Rover, Mercedes, Audi and VW are among the manufacturers producing turbodiesels.

As the piston begins to move down the bore, the inlet valve opens and air is drawn in.

A diesel engine operates differently from a gasoline engine, although they share key components and both work on the four-stroke cycle. The main differences are in the way the fuel is ignited and the way the power output is adjusted.

In a gasoline engine, the fuel/air mixture is ignited by a spark plug. In a diesel engine, ignition is achieved only by air compression. A typical compression ratio for a diesel engine is 20:1, compared to 9:1 for a gasoline engine. Compressions as large as this heat the air to a temperature high enough to ignite the fuel spontaneously, without the need for a spark and thus an ignition system.

Natural Gas Engines

A gasoline engine draws in different amounts of air for each intake stroke, the exact amount depending on the throttle opening. A diesel engine, on the other hand, always draws in the same amount of air (at any engine speed), through an unthrottled intake tract that is opened and closed only by the intake valve (it has neither a carburetor nor a butterfly valve).

When the piston reaches the effective end of its induction stroke, the inlet valve closes. The piston, carried by the power of the other pistons and the torque of the flywheel, travels to the top of the cylinder, compressing the air to about one-twentieth of its original volume.

When the piston reaches the top of its stroke, a precisely metered amount of diesel fuel is injected into the combustion chamber. The heat from the compression immediately ignites the fuel/air mixture, causing it to burn and expand. This forces the piston down, turning the crankshaft.

What Ignites The Fuel In A Diesel Engine

As the piston moves up the cylinder on the exhaust stroke, the exhaust valve opens and allows the burned and expanded gases to travel down the exhaust pipe. At the end of the exhaust stroke, the cylinder is ready for a fresh charge of air.

Diesel Vs. Gas Engines: What’s The Difference?

The main components of a diesel engine look like those of a gasoline engine and perform the same job. However, diesel engine parts must be made much stronger than their gasoline engine equivalents due to the much higher loads involved.

The walls of a diesel engine block are normally much thicker than a block designed for a gasoline engine, and they have more bearing webs to provide additional strength and absorb stress. In addition to being stronger, the hard block can reduce noise more effectively.

Pistons, connecting rods, camshafts and bearing caps must be made stronger than their gasoline engine counterparts. The design of the cylinder head must be very different because of the fuel injectors and also because of the shape of its combustion chambers and rotation.

Direct injection means that fuel is poured directly into the combustion chamber at the top of the piston crown. The shape of the chamber is better, but it is more difficult for the fuel to mix properly with the air and burn without producing the harsh “knock” characteristic of diesel.

How It Works: Diesel Engines

For any internal combustion engine to run smoothly and efficiently, fuel and air must be properly mixed. Fuel-air mixing problems are particularly large in a diesel engine, where air and fuel are introduced at different times during the cycle and must be mixed in the cylinders.

There are two main ways of direct injection and indirect injection. Traditionally, indirect injection is used because it is the easiest way to introduce turbulence so that the injected fuel spray mixes well with the highly compressed air in the combustion chamber.

In an indirect injection engine there is a small swirling spiral chamber (also called a pre-combustion chamber) into which the injector pours the fuel, before it reaches the main combustion chamber itself. The swirl chamber creates turbulence in the fuel so that it mixes better with the air in the combustion chamber.

What Ignites The Fuel In A Diesel Engine

The drawback of this system is that the swirl chamber effectively becomes part of the combustion chamber. This means that the combustion chamber as a whole is irregularly shaped, causing combustion problems and hindering efficiency.

What Happens If You Put Gas In A Diesel Engine?

Indirect injection means that the fuel is poured into a small chamber before combustion. This leads to the main combustion chamber. With this design, the ideal shape of the combustion chamber is compromised.

A direct injection engine does not have a swirl chamber into which the fuel is drawn – instead, the fuel goes directly into the combustion chamber. Engineers must pay very careful attention to the design of the combustion chamber in the piston crown to ensure that it creates enough turbulence.

To preheat the cylinder head and engine block before a cold start, diesels use glow plugs. They look like short, solid zinc plugs and are connected to the car’s electrical system. The elements inside heat up very quickly after power is applied. The glow plugs are activated either by an auxiliary position on the steering column switch, or by a separate switch. In the latest models, they turn off automatically after the engine is started and accelerates above idle speed.

A diesel engine does not throttle like a gasoline engine, so the amount of air inhaled at any given engine speed is always the same. Engine speed is governed simply by the amount of fuel flowing into the combustion chamber – with more fuel

Common Rail Diesel Engines Explained: Should I Install One On My Boat?