Construction Mechanic Basic: Diesel Fuel Systems Chapter 5

Sediment or water is prevented from entering the fuel system because the inlet fuel line is how far from the bottom of the tank?

1 inches

What grade of diesel fuel is used in truck fleets because of its greater heat value?

2D

With the engine operating at full load, the transfer pump fills the injection pump housing with fuel at approximately _______ psi.

30 to 35

Current diesel fuels have a cetane rating that ranges between _______.

40 and 50

At approximately what rate, in gallons per hour, does the constant bleed valve return fuel back to the fuel tank?

9

What agency is responsible for grading diesel fuel?

American Society for Testing and Materials

Why is it necessary to have a supply pump to transfer fuel from the tank to the injection pump of a diesel engine?

Because the injection pump will not create sufficient suction

After replacing the injectors in a Cummins PT fuel system, you should readjust them after the engine has been warmed up to within what temperature range?

Between 160°F and 180°F

At what location is the governor connected on a diesel engine?

Between the throttle and the fuel injector

For engine speed to stabilize, what condition must exist within the governor?

Centrifugal force and spring tension must be equalized

If the cetane number of a diesel fuel is too low, which condition can result?

Difficulty in starting

Which combustion chamber design is the most common?

Direct

What drives a turbocharger?

Exhaust

The sleeve metering fuel system uses what for lubrication?

Fuel

Which factor must be considered when selecting a fuel oil?

Fuel cost and availability

What component is designed to prevent an engine from over-speeding and allow the engine to meet changing load conditions?

Governor

Which characteristic is one advantage of the diesel engine over the gasoline engine?

High ratio of power output to fuel consumed

What type of cold weather starting devices uses convection as a means to transfer heat?

Immersion block heater

Which characteristic is NOT an advantage of a mechanical governor?

Large deadbands

What type of governor prevents an engine from exceeding a specified maximum speed?

Limiting-speed

What type of governor provides a regular or stable engine speed, regardless of load conditions?

Load-control

What type of governor is used on the sleeve metering fuel system?

Mechanical

What are the five functions of a diesel fuel injection system?

Meter, inject, time, atomize, and create pressure

In an electronic governor, at what location is the magnetic pickup sensor installed?

Next to a drive shaft gear

Blue smoke coming from the exhaust indicates the existence of which condition?

Oil entering the combustion chamber

What action limits the maximum amount of fuel that can be injected by the DB2 fuel pump?

Outward travel of the plungers

In the PTG-AFC fuel pump, what determines the AFC plunger position?

Positive boost pressure in the intake manifold

What type of injection system is used on Caterpillar diesel engines?

Pump and nozzle

What action controls the speed of a diesel engine?

Regulation of the amount of fuel delivered to the engine's cylinders

What part of a spring-loaded mechanical governor does the manual throttle directly adjust?

Spring tension

Which property has a direct bearing on the life expectancy of the engine and its components?

Sulfur content

What factor makes it possible to ignite the air-fuel mixture of a diesel engine without the use of a spark plug as required in a gasoline engine?

The compression temperature of the diesel engine is high.

When precombustion chambers are used on a diesel engine, which factor causes the greatest amount of fuel atomization?

Turbulence within the precombustion chamber

What action varies the metering of fuel in a Caterpillar injection system?

Turning of the plungers in the barrels

What type of seal is used to prevent engine oil from entering the DB2 fuel pump?

Two lip seals

What positive displacement type of transfer pump is used in the DB2 fuel pump?

Vane

What type of governor maintains any specified engine speed between idle and maximum speed?

Variable-speed

The measure of the volatility of a diesel fuel is known as the _______ number.

cetane

The rate at which fuel is injected also determines the rate of_____.

combustion

The tension of the spring in the mechanical flyweight governor has a tendency to _______.

increase the amount of fuel delivered to the cylinders

Low volatile fuels tend to provide better fuel economy and produce _______.

less exhaust smoke

When overhauling a set of PT fuel injectors, you must keep them together because they are a ______ sets.

matched

The hydraulic governor is inherently unstable. To maintain stability, hydraulic governors employ _______.

speed droop