Who invented the diesel engine and when?

A guy named Dr Rudolf Diesel who was a mechanical engineer which invented the diesel engine in the 1897. He moved on to creating other systems along side and to work with the diesel engine.

What fuel pressure would you get from a diesel lines?

From the normal diesel engine the pressure is much lower as it uses an injector pump which pumps out at about 150bar and on a common rail diesel engine it is much higher and only trained technicians can work on these fuel lines as the can put out at least 1000bar/1500psi but pressures can be much higher the third generation of common rail can reach up 26,000psi which could easily cut off your hand.

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

There is two types of diesel injection pump there is a rotor type and an inline type. The rotor design has a hollow cylinder with ports and a cam which is supplied fuel to as it turns , as it spins it opens the ports directing the fuel into the cylinder's. The more commonly used inline system has a cylinder for each in the combustion chamber and uses a piston which moves in sequence with the piston in the engine and each time it pumps fuel up to the injectors to be sprayed. Because the fuel must be sparyed into the cylinder at the right time to ignite the fuel if the timing is wrong the engine will run rough and puff out smoke or not run at all.

How do you time the pump and with what equipment would you use?

First you will start by puting your engine to TDC then you will remove the cambelt then look and line all of the timing marks up including the diesel pump. Then you will put the cambelt on without moving the marks. Tighten up the belt then screw a D.T.I gauge in the back off the diesel pump. Then in the manufactures specs it will tell u to set the engine 3degrees before top dead centre then turn the engine at look at the gauge and it will tell you a reading which you will check in the specifications. You will need a timing light to check if everything is in proper order, you will also need a D.T.I gauge that has a fitting to go in the back of the pump, you will need a socket set spanners and a big screw driver or bar.

How does the diesel injectors work?

The diesel injector is bigger then a normal injector and has diesel feed to it from the top it also has a pump which pumps air into the injector which highly pressurizes the fuel then the needle valve opens spraying the  atomized fuel out the nozzle which has many holes in it which sprays the mixture throughout the combustion chamber which ignites in the pressurized cylinder.

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


When removing the filter or pump you automaticly will be letting air into the system which will affect the running of the engine because instead of having diesel there will be just air which may cause a air lock. You must full the filter cup up after then bleed the system  to remove the left over air


How do you bleed the system?

 

Once you have changed your new filter you should fill the filter cup with clean diesel then screw together. Then you open the bleed screw on the side of the hand primer and pump it till you see there are no bubbles or air with the fuel Then you should crank the engine and see if its running good but if not you must bleed the injector pipes. You crack the bolt then crank the engine which will make fuel spray out , once there is no bubbles tighten the pipe and carry on bleeding each injector pipe one at a time.

How does a turbo work?

 A turbocharger is a component which is mounted on the exhaust manifold which is designed to force air into the combustion chamber to increase engine torque or power it does this by using the exhaust gases passing by it to spin a propellor and shaft which spins the opposite side of the turbo which has another propellor which sucks in air from the air intake and forces it into the throttle body

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

The knock sensor is a sensor that is put in to detect knock or pinking in the engine it has thing called a piezo crystal inside it that as it is hit or knocked it sends out a voltage to the ECU which retards or advances the timing to stop the knock it is mounted on the side of the cylinder block.

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

 

The glow plugs are put in place to pre-heat the combustion chamber before the diesel engine is started if it has no glow plugs it wont start or will take a lot of time to heat the cylinders. You would test the resistance in each of the glow plugs if it doesn’t show a reading then its defective and if it does show a reading then check the specifications for these plugs.

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

 With any internal combustion engine if more air or fuel is added it will produce more power and diesels normally run at low rpms which means they cant really suck in as much air as they need so that is why a turbo is fitted so give more air at certain rpm ranges.

What is a supercharger?

A supercharger is another component which uses forced induction to increase engine power and torque this is a belt driven component which as the belt is spun it  which spins impellors inside the supercharger which sucks in air from the atmosphere and pushes itaround the impeelors and pushes it out into the throttle body. The disadvantage of the supercharger is it uses alot of engine power to run so if the engine is putting out 350 horsepower the supercharger will be using 50 horsepower to run so theonly 300 horsepower can be supplied to the wheels.

Whats the difference between a turbo and supercharger?

The difference between the turbo and supercharger is that the turbo uses the exhaust gases passing it to run and suck in air while the supercharger uses engine power to produce the forced induction. The turbo is more effecient because it uses wasted energy to run rather then engine power.

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

 An intercooler is designed like a radiator it has fins which air passes through to cool the air which is flowing through the intercooler. The reason an intercooler is put in is to cool the air before it is forced into the throttle body so the air is less dense. If the air is to hot it could cause engine damage by pre-ignition or detonation.

What is the electronic fuel shut off valve used for?

The electronic fuel shut off valve is used to shut off all fuel going into the engine incase of an emergency or if the ignition is turned off which automatically shuts the engine off. It is controlled by a solenoid which as power is supplied to it , it creates a magnetic field which opens or shuts a valve which is supplying the fuel.

What is the purpose of the governor?

The governor is put in place to keep the engine below a certain rev range and because diesel engines are not self speed limiting the govenor is put in to give engine feedback to know when to change the engine speed and to keep it at a constant speed once reached there are many types of governors for different purposes