Deck 22: Port-Helix Metering Injection Pumps

Question 1

What type of diesel fuel system is usually being referred to when it is described as PLN (pump-line-nozzle)?

A) pressure-time system
B) MUI system
C) EUI system
D) port helix metering system

Answer 1

port helix metering system

Question 2

In a typical port helix metering pump, which of the following components is rotated?

A) pump barrel
B) camshaft
C) tappets
D) control rack

Answer 2

camshaft

Question 3

When a port helix metering pump is phased to a 4-stroke cycle engine, how many times does the engine rotate through one complete pump revolution?

A) 180 degrees
B) 1 revolution
C) 2 revolutions
D) 4 revolutions

Answer 3

2 revolutions

Question 4

What is used to support the camshaft in a port helix metering pump in the cambox?

A) bearings
B) bushings
C) hydrodynamics
D) pedestals

Question 5

At what pressure is the fuel gallery in a port helix metering pump charged?

A) charging pressure
B) residual line pressure
C) leakoff circuit pressure
D) nozzle opening pressure

Question 6

Where is the oil sump located in a port helix metering injection pump?

A) tappet bay
B) charging gallery
C) cambox
D) flange housing

Question 7

Which is the stationary member of the pumping element used in a port helix metering pump?

A) tappet
B) plunger
C) delivery valve body
D) barrel

Question 8

Which is the reciprocating member of the pumping element used in a port helix metering pump?

A) barrel
B) plunger
C) tappet
D) control rack

Question 9

Plunger to barrel clearances are lapped in manufacture in port-helix metering injection pumps to tolerances between:

A) one half and one micron
B) two and four microns
C) six and eight microns
D) ten and twelve microns

Question 10

Convert one bar to an approximate psi value:

A) 15 psi
B) 30 psi
C) 60 psi
D) 120 psi

Question 11

Convert 75 psi to bar and round to one of the following values:

A) two bar
B) four bar
C) five bar
D) six bar

Question 12

Which of the following is true about actual plunger stroke in a port helix metering injection pump?

A) it is constant
B) varies with engine speed
C) varies with fuel requirement
D) varies with manifold boost

Question 13

What component is responsible for managing plunger effective stroke?

A) tappets
B) camshaft
C) control rack
D) delivery valve

Question 14

Which of the following is true regarding plunger effective stroke:

A) it is constant
B) varies with engine rpm
C) varies with fuel requirement
D) varies with manifold boost

Question 15

What is the uppermost part of a plunger used on a port helix metering pump known as?

A) upper helix
B) vertical slot
C) plunger lugs
D) plunger leading edge

Question 16

When the plunger on a port helix metering pump is at TDC, what else is true?

A) delivery valve is open
B) the pump chamber is at peak pressure
C) cam is on outer base circle
D) cam is on base circle

Question 17

What event begins the effective stroke in a port helix metering injection pump?

A) port opening
B) port closure
C) delivery valve opening
D) delivery valve closure

Question 18

What event ends the effective stroke in a port helix metering injection pump?

A) port opening
B) port closure
C) delivery valve closure
D) injector closure

Question 19

How is the engine being fueled when the vertical slot aligns with the spill port throughout plunger stroke?

A) full fuel
B) high idle fuel
C) peak torque fuel
D) no fuel

Question 20

What is the reason for using helices milled diametrically opposite on a plunger?

A) increase fuel quantity
B) decrease fuel quantity
C) improve lubrication
D) hydraulic balance

Question 21

At what point during effective stroke does the slug of fuel in the pump chamber unite with fuel in the high pressure line?

A) when delivery valve unseats
B) when retraction piston rises above seat
C) when delivery valve is fully open
D) when injector opens

Question 22

What event causes pressure collapse to occur in the pump chamber of a port helix metering pump?

A) port closure
B) port opening
C) delivery valve opening
D) delivery valve closure

Question 23

When the plunger metering recesses have minimum exposure to the spill port(s) through plunger stroke, how is the engine being fueled?

A) full fuel
B) no fuel
C) half fuel
D) idle fuel

Question 24

What component is directly responsible for moving the control rack in a mechanical port helix metering injection pump?

A) camshaft
B) speed control lever
C) decompression lever
D) governor

Question 25

Which of the following is the most common method of shutting down an engine fueled by a hydromechanical port helix metering injection pump?

A) control rack to no fuel
B) de-energize shutdown solenoid
C) energize shutdown solenoid
D) choke off intake air

Question 26

What happens to fuel in the pump chamber of a port-helix metering pump at port opening?

A) fuel is forced through the delivery valve
B) fuel spills to the charging gallery
C) fuel exits the fuel injector
D) fuel is re-routed to the transfer pump

Question 27

What is the function of the flutes machined into a delivery valve?

A) seal the valve before it seats
B) define dead volume pressure
C) guide the valve in the delivery valve body
D) define delivery valve opening pressure

Question 28

Which of the following does most to define the residual line pressure value?

A) sectional area of the delivery valve
B) length of the flutes
C) peak injection pressure value
D) swept volume of the retraction piston

Question 29

In an operating port-helix metering injection pump, the term dead volume fuel refers to:

A) fuel retained in the high pressure line between injection pulses
B) fuel held in the leak-off circuit
C) fuel in the fuel pump chamber when the plunger is at the top of its stroke
D) fuel held in the fuel tank

Question 30

A plunger in a port-helix metering pump with a lower helix would produce which of the following timing characteristics?

A) variable beginning, variable ending
B) variable beginning, constant ending
C) constant beginning, variable ending
D) constant beginning, constant ending

Question 31

What is used to seal fuel in the plunger/pump chamber from the cambox in a typical port-helix metering pump?

A) rubber seal
B) neoprene seal
C) viscous seal
D) anaerobic seal

Question 32

If an electronically controlled, variable timing device with a 20 degree timing window has to be static timed at 8 degrees BTDC, where can port closure occur?

A) 8 degrees BTDC only
B) between 8 degrees BTDC and 12 degrees ATDC
C) 28 degrees BTDC only
D) between 28 degrees BTDC and 8 degrees BTDC

Question 33

Which of the following terms means the same thing as static timing?

A) port closure timing
B) port opening timing
C) injection timing
D) ignition timing

Question 34

What replaces the governor housing in an electronically controlled, port-helix metering injection pump?

A) rack actuator housing
B) computer module
C) sensor housing
D) transducer module

Question 35

What is the function of an aneroid used in the governor of a port-helix metering injection pump?

A) measure fuel injection pressure
B) meters fuel to the engine
C) measures manifold boost
D) measures cylinder pressure

Question 36

What is used to lubricate the cambox components in a typical highway truck, port-helix metering injection pump?

A) dedicated oil in the cambox sump
B) lithium base, high temperature grease
C) fuel at charging pressure
D) engine lubricating oil circuit

Question 37

When an altitude compensator is used on the governor of a hydromechanical port-helix metering injection pump, what does it do?

A) provides excess fuel at high altitudes
B) limits fueling (derates) at high altitudes
C) uprates engine power on hills
D) compensates for high oxygen density

Question 38

Which of the following port-helix metering pump, static timing procedures would provide the least accuracy?

A) high pressure
B) timing pin
C) transducer and timing light
D) electronic

Question 39

Which of the following port-helix metering pump, static timing procedures would provide the highest accuracy?

A) high pressure
B) timing pin
C) transducer and timing light
D) electronic

Question 40

Which of the following explains the need to bar the engine only in its correct direction of rotation when timing a hydromechanical port-helix metering, injection pump to an engine?

A) delivery valve core seating
B) engine timing gear backlash factors
C) timing index location
D) calibration pointer location

Question 41

When adjusting static timing on a hydromechanical, port-helix metering injection pump to the engine, which of the following steps in the procedure should be performed last?

A) remove the delivery valve core
B) remove the high pressure line
C) locate injection pump port closure
D) loosen pump drive plate to drive gear fasteners

Question 42

What would the phase angle be on a port-helix metering injection pump fueling a 4-stroke cycle diesel engine?

A) 30 degrees
B) 60 degrees
C) 120 degrees
D) 360 degrees

Question 43

Which of the following procedures would adjust the phase angle of one pump element in a port-helix metering injection pump?

A) shimming the fuel pump drive gear
B) rotating the barrel
C) shimming the barrel flange
D) repositioning the control rack

Question 44

Which of the following procedures would be the correct method of recalibrating fuel output from one pump element on a port-helix metering injection pump?

A) rotating the barrel
B) shimming the barrel flange
C) advancing port closure timing
D) increasing the charging pressure

Question 45

What does a variable timing device such as Econovance allow an ECM managing a Bosch 8500 injection pump to control?

A) exact moment of ignition
B) injection timing advance
C) centrifugal timing advance
D) engine cylinder pressure

Question 46

What is used to move the fuel rack in an electronically-controlled, Bosch 8500 injection pump?

A) governor assembly
B) rack position sensor
C) rack actuator
D) hydraulic servo

Question 47

If there was a complete electrical failure in an electronically-managed Bosch PE 8500 fuel pump, which of the following would result?

A) no engine restart after driver shuts down
B) check engine light is illuminated
C) shutdown strategy is initiated
D) fuel rack defaults to no-fuel followed by immediate shutdown

Question 48

In the Bosch PE 7100/8500 rack position sensor assembly, what is the difference between the measuring and reference coil windings?

A) measuring coil uses larger number of windings
B) none, they are identically wound
C) reference coil uses heavier gauge wire
D) reference coil has moving short circuit window

Question 49

What is used to signal engine position in a Bosch PE8500 pump with an RE30 rack actuator such as that used in a Mack Trucks V-MAC II managed engine?

A) camshaft position sensor (CPS)
B) crankshaft speed sensor (CSS)
C) timing event marker (TEM)
D) synchronous reference sensor (SRS)

Question 50

What is another way describing the linear magnet used as a rack position sensor in a Bosch 8500 fuel injection pump with an RE30 rack actuator?

A) potentiometer
B) Hall effect switch
C) linear proportioning solenoid
D) latching solenoid

Question 51

Which sensor must be removed from a V-MAC II, Bosch PE8500 fuel injection pump, to perform electronic static timing?

A) rpm sensor
B) timing event marker (TEM)
C) transducer module
D) camshaft position sensor (CPS)

Question 52

If a 20 degree Econovance unit is installed to a V-MAC, Bosch PE8500 injection pump and static timing is specified at 7 degrees before TDC, what is the maximum possible port-closure advance?

A) 13 degrees ATDC
B) 7 degrees BTDC
C) 13 degrees BTDC
D) 27 degrees BTDC

Question 53

In which of the following applications would a hydromechanical port-helix metering pump be found in an EPA MY 2017 compliant onhighway application?

A) Pick up and delivery van
B) Reefer powerplant
C) LTL tractor
D) Linehaul tractor

Question 54

Technician A says that only offshore engines are permitted to use port-helix metering fuel systems on EPA MY 2010 compliant and later engines. Technician B says that port-helix metering injection pumps can be used on current diesel engines when the peak power rating is less than 70 BHP (52 kW). Who is correct??

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