Q4-11.
Which of the following circuits controls a
Q4-5. Most fuel level gauges are electrically
small amount of fuel that is momentarily
operated and consist of what two compo-
discharged into the airstream when the
nents?
throttle is opened quickly?
1.
A gauge and a sending unit
1.
The high speed circuit
2.
A level indicator and a float
2.
The accelerator pump circuit
3.
A gauge and a level indicator
3.
The low speed circuit
4.
A float and a sending unit
4.
The acceleration stabilizer circuit
Q4-6. Excessive fuel pump pressure in a gasoline
Q4-12.
What is the reason a choke is set during initial
engine fuel system will cause which of the
starting of an item of SE?
following actions?
1. To reduce the amount of fuel required for
1. It will cause the fuel float to stick in the
starting
closed position
2. To increase the air turbulence in the car-
2. It will hold the fuel float needle valve off
buretor throat
its seat
3. To reduce the air velocity in the carbure-
3. It will increase the engine speed
tor throat
4. It will not affect the engine performance
4. To reduce the amount of air entering the
because of the pressure regulator
throat
Q4-7. What is an average fuel pump operating pres-
Q4-13.
In which of the following locations is the
sure?
intake manifold located?
1.
1 to 4 psi
1.
Between the head and the block
2.
3 to 5 psi
2.
Between the head and the carburetor
3.
5 to 10 psi
3.
Between the carburetor and the block
4.
5 to 15 psi
4.
Between the carburetor and the air filter
Q4-8. Which of the following fuel pumps is normally
found in a gasoline engine?
THE DIESEL FUEL SYSTEM
1.
A positive displacement pump
LEARNING OBJECTIVE: Identify the
2.
An electric pump
properties of diesel fuel. Identify the most
3.
A diaphragm pump
common types of combustion chambers used
4.
A non-positive diaphragm pump
in support equipment.
Q4-9. What is the purpose of the venturi in a car-
Like the gasoline engine, the diesel engine is an
buretor?
internal combustion engine that uses either a 2- or
1. It restricts the flow of fuel to create a
4-stroke cycle. Power is obtained by the burning or
greater pressure
combustion of fuel within the engine cylinders. The
2. It creates a backpressure at the fuel noz-
diesel engine does not use a carburetor because the
zle
diesel fuel is mixed in the engine cylinder with the
3. It creates a vacuum at the outlet of the fuel
compressed air.
nozzle
Compression ratios in the diesel engine range from
4. It restricts the flow of air to the intake
14:1 to 19:1. This high ratio causes increased com-
manifold
pression pressures of 400 to 600 psi, and cylinder
Q4-10.
What circuit in a carburetor permits the flow
temperatures reach 800 to 1,200F. At the proper time,
of fuel into the carburetor bowl?
the diesel fuel is injected into the cylinder by a fuel
1.
The float circuit
injection system, which usually consists of a pump, fuel
2.
The fuel regulation circuit
lines, and injector or nozzle. When the fuel enters the
3.
The fuel level circuit
cylinder, it will ignite because of the high temperature.
4.
The fill circuit
The diesel engine is known as a compression-ignition
engine, while the gasoline engine is a spark-ignition
engine.
4-18
