Diesel Engine Questions

Who invented the diesel engine and when?

The engine is named after Dr.Rudolf Diesel, of Germany, who produced his first engine in 1893.

What fuel pressure would you get from a diesel pump?

pumps vary from 3 and a half psi up to nearly 5 psi when the engine is in idle, this changes when the engines RPM goes up and the pressure increases.

How does the diesel pump work and why do we need to time the pump?

 Many electronic diesel engine control systems use a conventional in-line or distributor fuel injection pump, but the injection pump timing and the quantity of fuel injected are controlled electronically instead of mechanically. Many electronic sensors are used to measure variables such as accelerator pedal position, engine crankshaft speed, engine camshaft position, the mass of air passing into the engine, turbocharger boost pressure, engine coolant temperature, ambient air temperature, etc.

What is the purpose of a glow plugs and how do you test the circuit?

A glow plug normallyis made up of  a heating coil in a metal tube closed at one end and filled with electrically insulating ceramic. The closed end of the metal tube with the heating coil protrudes through a hole in the cylinder head into the combustion chamber. When the glow plug is electrically energized, when the plug is heated it brings the ceramic tip up to over 1000 degrees in seconds and heats the air surrounding it. this means when the fuel/air passes through it is heated very quickly.

Why do we need an lift pump on diesel engine?

Why do we need a electronic fuel shut of valve?

What is the knock sensor for and where is it situated?

It allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor finds pinging. At that point the computer retards the ignition timing just enough for the pinging to stop. A knock sensor makes sure that you're getting as much power and fuel economy as is possible from your engine at any time.

How does the diesel injectors work?

Basic diesel fuel injectors contain the following parts, a fuel supply line, an intake valve, an exhaust valve and the fuel injection apparatus. Each cylinder has its own fuel supply line, all of these lines run from the fuel tank to the engine. Fuel is pumped through these fuel supply lines to the fuel injector device which is connected to each of the cylinders.

Why do you need to bleed a diesel engine after replacing a fuel filter or removing the pump?

because when you connect everything up again there may be air in the fuel line and the stream of diesel may be interrupted and then when you go to start the engine again it will be very hard to start or may not because of the lack of constant fuel.

How do you bleed the system?
Disconnect the fuel line to the cylinders and crank the engine, the fuel should just start to flow from the line and what until there is a constant stream then stop, do not crack it for too long as it will damage the engine.

How does a turbo work?

Basically, the exhaust from the engine gets pushed into the charged air cooler which then cool it rapidly around 30 degrees Celsius before being thrusted into the air intake manifold, this improves the performance of the engine. The exhaust gases are routed by the turbine side of the turbocharger causing the turbine wheel to rotate at speeds of up to 100,000 rpm. A turbo charger on a diesel engine does not operate as a power adder as it does on a gasoline engine. A turbo on a diesel engine works to match air to fuel and with the added air, more fuel can also be injected which is why turbo diesels can have more torque and HP. If the turbo starts to go on a diesel you will see losses in power and fuel economy.

Why do we need a turbo fitted to a diesel engine?

A turbocharger delivers boost, this increases the power of the engine as well as fuel consumption only when the added power is demanded by putting the engine under a heavy load. A turbodiesel-powered vehicle accelerating from rest, will put its engine under a much larger load than conventional diesel engine, this causing high boost pressures to be delivered by the turbocharger to the engine. This is detected by the fuel injection system which delivers more fuel to the engine when it is needed. Once the vehicle reaches a constant speed and constant RPM the load will drop much more and start to settle, the pressure that is flowing through the turbo drop, fuel injection rate decreases, in turn lowering fuel consumption to very similar levels as a normal diesel engine.

What is a supercharger?

A supercharger is mounted to the engine and is driven by a pulley that is connected to the crankshaft. Air is sucked into the supercharger and compressed by either an impeller , twin rotating screws, or counter-rotating rotors. The air is then sent into the engine's intake manifold. when the engine is operating at Faster crank speed it spins the supercharger faster and allows the supercharger to produce more power quickly. The normal peak operating speeds for a supercharger are around 15,000 rpm.

Whats the difference between a turbo and supercharger?

Adding a supercharger will increase the power of the engine by forcing air into the manifold, a super charger is similar to a turbocharger in the sense that it pressurizes air above the atmospheric pressure. The only difference between the two is the source of energy, the turbo is powered by the exhaust fumes pushing a turbine and the supercharger is driven mechanically by the engines crankshaft.

Why do we need a after- cooler or inter-cooler fitted to a diesel engine?

Inter-coolers are only fitted to turbo or supercharged engines, they are fitted to cool the engine because when one of the two components are working they create a large amount of heat in the intake manifold and if it is left to overheat there may be heat damage and the component will not operate as well as it could. the performance of the engine will increase if the inter-cooler if fitted properly, this is because the density of the air will be increased due to the amount of air entering the manifold. scoops on the bonnets of turbo cars are where the inter-cooler is mounted as this acts as a funnel to help with air collection.
What the difference between  in a direct-injection ( DI,) an indirect-injection ( IDI)?

The term indirect injection means, fuel injection where fuel is not directly injected into the combustion chamber. An indirect injection diesel engine delivers fuel into a chamber which is set off the side of the combustion chamber called a prechamber,The prechamber is designed to ensure the appropriate mixing of the atomized fuel with the compression-heated air. This has the effect of slowing the rate of combustion, which in turn reduces the audible noise. In addition, it softens the shock of combustion and produces lower stresses on the engine components. The addition of a prechamber, however, increases heat loss to the cooling system and then lowers engine efficiency.

What is the purpose of an governor?

All that a governor is, is just a speed limiter in essence that will stop the engine from reaching a certain RPM. the usual way they do this is to fit a centrifugal governor attached to the shaft that uses weights with springs and arms. for example on a aircraft the propeller has a centrifugal governor attached to sense the rpm of the prop to that the angle of the blades can be adjusted to keep the rpm of the engine at the same speed even when the aircraft is in a dive or is climbing.

WEBSITES:

en.wikipedia.org/wiki/Glowplug
autorepair.about.com/od/.../l/aa081404a.htm 
http://en.wikipedia.org/wiki/Indirect_injection
http://auto.howstuffworks.com/turbo2.htm
http://en.wikipedia.org/wiki/Turbocharger
http://en.wikipedia.org/wiki/Governor_%28device%29
http://www.howstuffworks.com/diesel.htm