Deck 10: Electronic Diesel Fuel Injection Systems

Question 1

What is required to accurately diagnose HEUI system malfunctions?

A) Manufacturers diagnostic software.
B) A generic scan tool.
C) A proprietary scan tool.
D) A full set of HEUI manuals.

Answer 1

A

Question 2

What distinguishes a Siemens HEUI from a Caterpillar HEUI?

A) External solenoid.
B) Dual integral actuators.
C) Single actuator.
D) Larger physical size.

Answer 2

B

Question 3

From 2010 onward, what type of electronic fuel injection is used in most EPA approved light duty diesel engines?

A) Electronic unit injectors (EUI).
B) Hydraulic electronic unit injectors (HEUI).
C) Subcompact nozzle injectors.
D) Common Rail (CR).

Answer 3

D

Question 4

What is the purpose of a flow limiter?

A) Dampen sudden changes in fuel flow.
B) Signal fuel flow to the PCM.
C) Limit fuel flow depending on engine rpm.
D) To act as a fail-safe to prevent over fueling.

Question 5

What is the injector driver output voltage used to actuate a Siemens HEUI?

A) 115 volts DC.
B) 12 volts DC.
C) 12 volts AC.
D) 48 volts DC.

Question 6

In a common rail (CR) fuel system how are injection pressures are maintained?

A) In the primary circuit.
B) In the entire rail assembly and injector circuit.
C) Throughout the fuel subsystem and high pressure circuits.
D) In the secondary circuit.

Question 7

If a fuel management system is described as full authority, which of the following must be used?

A) Engine management computer.
B) Turbocharger.
C) Mechanical variable timing.
D) Electromechanical governor.

Question 8

Which of the following is NOT a type of full authority fuel management system used on light duty diesel engines?

A) CR.
B) EUI.
C) HEUI.
D) PLN.

Question 9

What provides the mechanical force to produce injection pressures in an EUI system?

A) Solenoid.
B) Piezoelectric crystals.
C) Lever.
D) Camshaft.

Question 10

What is used as the hydraulic actuation medium in a HEUI system?

A) Diesel fuel.
B) Engine oil.
C) Coolant.
D) Hydraulic fluid.

Question 11

What is the calibration port on an EUI used for?

A) On-engine calibration during regular service intervals.
B) Re-calibration after repairs to the fuel system.
C) To access calibration data set by the manufacturer.
D) Define a fuel flow calibration specification.

Question 12

What does the PCU use to control effective stroke in an EUI fuel system?

A) Cam profile.
B) Nozzle valve actuator.
C) Control valve actuator.
D) Fuel subsystem pressure.

Question 13

Compared to gasoline direct injection fuel systems, diesel CR systems operate at:

A) Much lower combustion temperatures.
B) Much higher rotational speeds.
C) Much higher injection pressures.
D) Much lower injection pressures.

Question 14

Which of the following types of fuel pump can be used as the high pressure pump in a typical CR systems?

A) Vane pump.
B) Swash plate pump.
C) Crescent pump.
D) Inline piston pumps.

Question 15

What type of valve is used on CR fuel system to manage rail pressures?

A) PCM-controlled spool valves.
B) Choke valve.
C) PCM-controlled rotary valve.
D) Gate valve.

Question 16

Where is the flow limiter located on a Bosch CR system?

A) Inside the EHI.
B) Between the rail and the EHI high pressure line.
C) Between the inlet to the high pressure pump and the rail.
D) Next to the pressure limiter valve.

Question 17

In a HEUI system how is the desired injection actuation pressure determined?

A) Ambient temperature.
B) Depends on accelerator pedal angle.
C) Calculated by the PCM.
D) Sensed by rail pressure sensor.

Question 18

What is used in an amplified CR system to increase injection pressures?

A) Mechanical force.
B) Solenoid valve.
C) Piezo stack.
D) Intensifiers.

Question 19

In an EUI system what is the primary PCM output used to control fuel quantity?

A) Fuel transfer pump actuator.
B) EUI control actuator.
C) Throttle position angle.
D) Variable capacitance sensors.

Question 20

Providing a short duration injection pulse prior to main injection pulse is referred to as:

A) Pilot injection phase.
B) Multi-injection phase.
C) Delayed injection phase.
D) Injection overlap.

Question 21

Technician A states in a CR system the desired rail pressure is monitored by the rail pressure sensor. Technician B states in a CR system actual rail pressure is calculated by the PCM. Who is correct?

A) Technician A only.
B) Technician B only.
C) Both A and B.
D) Neither A nor B.

Question 22

Technician A states rail pressure limiter valves limit maximum rail pressure and are calibrated to trip at pressures slightly above the peak rail pressure. Technician B states high pressure fuel lines are protected by the rail pressure limiter valve and are designed only to withstand pressures at or below the trip pressure. Who is correct?

A) Technician A only.
B) Technician B only.
C) Both A and B.
D) Neither A nor B