Diesel Important Terms Revision Flashcards
define Diesel Fuel injection system
a high pressure mechanical system that delivers Fuel directly to the engine combustion chambers
injection pump
an engine driven mechanical pump that is responsible for delivering fuel to injectors under the right pressure and time
injection lines
connects the entire diesel injection system together, they consist of low pressure and high pressure lines.
high pressure lines are thicker and can withstand more pressure it is used when connecting the injection pump to injectors.
low pressure lines are smaller and uses for return lines and supply lines
injector nozzles
refers to the entire injector, they are spring loaded vales that spray fuel under the right pressure and pattern into the combustion chamber
glow plugs
these are heater elements that assist the diesel engine in cold starting, by heating air
diesel fuel supply system
this refers to everything between the high injection pump and fuel tank that delivers fuel to the injection pump.
this includes
fuel filters
inline fuel pumps
lift pumps
sedimenters
low pressure lines
and the fuel tank
inline diesel injection pump
a mechanical engine driven pump with a pumping element arranged in a straight line for each cylinder.
injection pump camshaft
this refers to the internal camshaft on an inline pump that controls the pumping action of pumping elements
injection pump roller tappets
these ride the internal camshaft lobes of an inline pump and is directly connected to plunger.
inline pump plungers
this is cylindrical plunger that can rotate freely inside a barrel with a helix cutout. The position of the helix on the plunger determines how much fuel is delivered to injectors.
Helix has different positions eg:
maximum postion
fuel shut off position
for different engine conditions
Barrel
is the sleeve in which houses the plunger an allows it to rotate freely and move up and down. it has an inlet port and spill port connected to a common gallery which is covered and uncovered by plunger operation.
plunger return springs
return springs that keeps the plunger in contact with camlobe at all times
control sleeve
alter the amount of fuel pushed to each injector nozzle by rotating the plunger which inturn changes the position of the helix
control rod and rack
a toothed shaft thay meshes with the control sleeve and and acts a throttle to control engine speed a power by rotating the control sleeve
delivery valves
these are fitted over each pumping element they prevent backflow of fuel into the plunger, maintain line pressure, and allows for dribble free closing of injectors.
internal components of the delivery valve include:
unloader collar (acted on by fuel and moves the valve off the seat)
valve (sits on a seat and prevents back flow of fuel
delivery valve spring( quickly shuts off the fuel to allow for rapid closing of injectors)
volume reducer ( further increases line pressure to the injectors)
effective plunger stroke
this is the amount of plunger movement that pressurize fuel
distributor injector pump
is a mechanical pump that may also be known as the rotary or dpa type pump. It uses one or two plungers along an internal cam ring or cam plate with lobes to send fuel to multiple cylinders. Distributor pumps are smaller and cheaper than inline pumps and are self lubricating. They require no periodical phasing or calibration
drive shaft
transfers engine power to the injection pump
transfer pump
a small internal pump that transfer fuel to the injection pump. this lubricates the pump and fills its pumping chambers. transfer pumps are usually vane type pumps
distributor plunger
small piston that produces high fuel pressure.
cam plate
rotating lobed disk that operated the plunger. like the inline pump camshaft it forces plungers to move and create pressure
fuel metering sleeves
found on a distributor pump houses the fuel metering valve and controls the amount of fuel being delivered by plungers to the injectors. the fuel metering sleeve is controlled by hydraulic governor and accelerator pedal
hydraulic head
the metal housing that surrounds plunger and contains passages for filling the barrels with fuel
certifugal governor
helps keeps the engine at a safe operating speed by using a flyweight to control the metering sleeve
governor
keeps the engine at a safe maximum rpm, allows the driver to control speed and power and ensures that the right amount of fuel is delivered to injectors under all load and speed conditions.
3 types:
flyweight
pneumatic
leafspring
diesel engine requires governors because the power and speed is controlled by the amount of fuel being burnt. if left unchecked the engine will over run and damage itself
centrifugal
a rotary motion that pushes force outwards. On a flyweight governor the weights on the end of flyweight increases in force with engine speed allowing the control rack to move back to a safe operating range at all loads and speeds.
distributor rotor
and internal slotted shaft with drilled ports that transfer fuel to plungers and distributes fuel to injectors at the right timing. used on distributor pumps
