A diesel pump, in the first engines, would have been powered by the engine using a connection straight to the engines crankshaft. The diesel pump will be timed to inject the diesel into the engine at the right time throughout the pistons stroke.
Commonly a diesel engine in your regular car, van or lorry will be of the four stroke sort, larger engines used in ships and hefty machinery will regularly be of the two-stroke kind to boost fuel performance. Two-stroke engines you would normally find in a moped or model plane, of course these use petrol to operate.
The main variation with a two-stroke engine is that the primary and last strokes are completed simultaneously, this has the result of drastically increasing efficiency at the cost of a dirtier exhaust. Another benefit is that two-stroke engines can be effortlessly run in reverse, providing a reverse function without the need for complicated gearing mechanisms.
In the current engine there are two key sorts of diesel engine, those are the common rail diesel engine and the electronic unit direct injection.
An electronic unit direct injection assembly combines the injector and diesel pump into a singe part, the diesel pump is, normally, still driven by the engine. An Overhead Camshaft (OHC) drives the diesel pumps and injectors, this is an assembly sat on top of the motor and attached directly to the engines main cam shaft by chain, or more commonly now, a belt.
The common rail diesel engine consist of a high pressured fuel rail, basically a manifold, supplying individual diesel fuel injectors versus the diesel pump supplying fuel directly to the fuel injectors.
As stated, above, your modern diesel engine operates on a four stroke cycle. You possibly will have heard this called the Otto cycle after the inventor of the gasoline engine, Nikolaus August Otto in 1876. A few years afterward Rudolf Diesel arrived and, wishing to create a more fuel efficient motor, came up with the diesel engine in 1892.
Diesel engines have been a bit sluggish on the up-take, for the common family car, largely due to their repute of being noisy and smelly. Clearly this is changing as innovative technology makes the diesel engine a more acceptable resolution to our modern transportation woes.
The four single events or strokes in a usual four stroke diesel engine are as follows:
The Intake Stroke: As the piston reaches the top of it's stroke and begins to move downward the air intake valve is opened, this has the consequence of air being drawn in as the piston travels down.
The Compression Stroke: As the piston reaches the bottom of it's stroke the air intake valve will close, as the outlet valve is also closed the air contained in the piston chamber is compressed as the piston travels back up the shaft.
The Combustion Stroke: As the piston reaches the peak of the compression stroke gas is injected at the exact moment by the diesel pump and as the piston is fractionally past the top of the upward phase of the compression stroke the diesel to compressed air mixture is ignited. This is where the power to drive the vehicle is produced, the piston is forced down driving the engine.
The Exhaust Stroke: In the pistons last upward stroke the outlet valve is opened and the gases produced from the ignition of the air to fuel mixture is forced out and into the exhaust mechanism. At the end of this stroke the four strokes are finished and the whole process starts again from the beginning.
One downside to diesel fuel as opposed to petrol is when used in very chilly climates. Diesel will begin to freeze at a higher temperature than gasoline, this will start off by the diesel becoming denser and waxy, clearly this will impede the good running of most diesel engine. One knack is to put a small amount of petrol into the diesel fuel mixture to help lower the freezing point of the overall mixture.
This furthermore has the additional benefit of making the overall mixture more explosive, though too great a mixture can damage a diesel engine, even small amounts of petrol in a common rail engine can trigger critical problems so talk to an experienced mechanic prior to altering your fuel combination.
Another trouble that can be easily spotted is if your diesel pump is malfunctioning, this has the outcome of reduced fuel supply or pressure to the fuel mechanism. Fundamental signs and symptoms are a failure of the engine to start, a lumpy or loud ignition, or a high pitched whining coming from the motor. You will probably also observe a lack of efficiency when applying the throttle.
If any of these situations crop up it would be highly recommended to get your vehicle checked out by a mechanic who may need to source you a new diesel pump.
