Deck 40: Hybrid and Hydrogen Fuel Cell Drivetrains

Question 1

Technician A says that a series hybrid electric vehicle (SEV) technology is used in some transit buses. Technician B says that rang-extended electric vehicles (REEV) are designed to primarily use electric drive. most commercial hybrid hydraulic vehicles use a diesel engine as the primary power source. Technician B says that most commercial hybrid electric vehicles use a diesel engine as the primary power source. Who is correct?

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

Answer 1

Both A and B

Question 2

For a fuel cell to convert energy to electricity it should be provided with:

A) Hydrogen only
B) Oxygen only
C) Hydrogen and oxygen
D) Water

Answer 2

Hydrogen and oxygen

Question 3

When a fuel cell is functioning, it produces:

A) Electricity only
B) Hydrogen only
C) Electricity and water
D) Electricity and oxygen

Answer 3

Electricity and water

Question 4

What principle do the Hydrogenics Ballard type fuel cells use?

A) Alkaline
B) Phosphoric acid
C) Solid oxide
D) Proton exchange membrane

Question 5

If a fuel cell is to be truly emissions-free, which of the following should be true regarding the source of the hydrogen?

A) produced using hydro-electricity
B) reformed using propane
C) produced using coal-driven electricity
D) reformed using gasoline

Question 6

When a diesel-electric hybrid drivetrain uses regenerative braking, retarding energy, which of the following is true? (braking force) is sourced from:

A) the traction motor's magnetic fields are reversed
B) Blended torque transmission reverses
C) the traction motor rotation is reversed
D) battery polarity is reversed

Question 7

Which of the following electro-chemical reactions could be considered to 'reverse' fuel cell principle?

A) ionization
B) static discharge
C) galvanic reaction
D) electrolysis

Question 8

What is the consequence of reforming natural gas (NG) to produce hydrogen?

A) Excessive NOx
B) Excessive CO
C) Excessive CO₂
D) Excessive PM

Question 9

When the hydrogen required by a fuel cell is 'reformed' from a gasoline source, what is the undesirable byproduct?

A) CO₂
B) static electricity
C) depleted gasoline
D) propane

Question 10

When fuel cell technology is used to power the Georgetown University bus, which type is used?

A) Phosphoric acid
B) Proton exchange membrane
C) Solid oxide
D) Alkaline

Question 11

Technician A says that all electrically-driven transit buses use fuel cell technology. Technician B says that current fuel cells can produce thermal efficiencies of up to 60%. Who is correct?

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

Question 12

If a drive technology is described as parallel hybrid (PH) what is the minimum number of drive sources required?

A) none
B) one
C) two
D) three

Question 13

In current hybrid electric vehicle (HEV) buses, what type of batteries tend to be used?

A) lead-acid
B) Li-ion
C) NiMH
D) Li-Po

Question 14

Technician A says that a key to making hybrid technology work is the blended torque transmission. Technician B says that a blended torque transmission can provide output using all-mechanical source torque, all-electric source torque, or any combination of either. Who is correct?

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

Question 15

Technician A says that a blended torque transmission (BTT) provides for continuously variable output ratios. Technician B says that for a planetary gearset such as those used in BTTs to produce an output, one of the three planetary members must be held stationary. Who is correct?

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

Question 16

When in regenerative braking mode, what does a diesel electric hybrid drivetrain produce?

A) engine torque
B) hydraulic potential
C) fast acceleration
D) electricity

Question 17

Technician A says that in a parallel hybrid hydraulic (PHH) drivetrain, drive torque is provided exclusively by a hydraulic motor. Technician B says that in a series hybrid hydraulic (SHH) drivetrain, drive torque is provided exclusively by a hydraulic motor. Who is correct?

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

Question 18

In a series or parallel hybrid hydraulic drivetrain in regenerative braking mode, what energy is produced and stored?

A) electrical potential in batteries
B) hydraulic potential in an accumulator
C) voltage potential in a motor
D) hydraulic potential to a pump

Question 19

Technician A says that PHH, SHH, and all forms of electric drive commercial vehicle are best suited to long distance linehaul operations. Technician B says that PHH and SHH technologies were pioneered by Eaton Corporation and the U.S. Army. Who is correct?

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

Question 20

Technician A says that diesel electric hybrid drive technology has been used in railway locomotives for several generations. Technician B says that advantages of both hydraulic and electric hybrid drive systems stem from using small bore diesel engines in much larger vehicles than a small bore engine would normally power. Who is correct?

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

Question 21

When electricity is used to directly power traction motors, what is the highest rate of thermal efficiency in current vehicles?

A) 40%
B) 60%
C) 80%
D) 100%

Question 22

Which of the following is required for a hydrogen fuel cell to produce electricity?

A) Hydrogen and Oxygen
B) Nitrogen only
C) Hydrogen only
D) Water

Question 23

What results from the electrochemical reaction in a hydrogen fuel cell?

A) Hydrogen and oxygen
B) Electricity and water
C) Eectricity only
D) Water only

Question 24

Which type of fuel cell is currently favored by commercial vehicles?

A) Alkaline
B) Solid oxide
C) Phosphoric acid
D) Proton exchange membrane (PEM)

Question 25

Technician A states that an advantage of a parallel hydraulic hybrid (PHH) drive system is that a small bore ICE can be used in place of a larger one. Technician B states that a PHH system can only impart hydraulic drive torque, so that in the event of a leak, the vehicle would be crippled. Who is correct?

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

Question 26

When a blended torque transmission is used in an HEV drivetrain transit bus, which of the following features are possible?

A) Input torque from more than one source
B) Continuously variable output ratios
C) Infinitely variable output speeds
D) All of the above

Question 27

What type of hydraulic accumulator is used in Eaton PHH and SHH drive systems?

A) Mechanically-loaded with a maxi-spring rated at 3,000 psi (207 bar)
B) Nitrogen gas-loaded at 5,000 psi (345 bar)
C) Hydraulically-loaded at 29,000 psi (2,000 bar)
D) Any of the above, depending on application

Question 28

Technician A says that HEV buses can use NG-fueled engines. Technician B says that HEV buses can use diesel engines. Who is correct?

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

Question 29

Which of the following is true of an HEV powertrain used in a typical urban vehicle?

A) Drive torque at the wheels is always 100% mechanical in origin.
B) Drive torque at the wheels is always 100% electrical in origin.
C) Drive torque at the wheels can be either electrical or mechanical in origin.
D) Drive torque at the wheels always originates from the RESS.

Question 30

Which of the following accounts for the significantly lower emissions produced by the small bore ICE used in an HEV?

A) The ICE can be mostly run at its optimum speed.
B) A small bore ICE uses less fuel.
C) A small bore ICE outputs less CO₂.
D) All of the above

Question 31

When a hydrogen fuel cell cogenerates waste heat, what happens to its overall thermal efficiency?

A) Actual thermal efficiency decreases
B) Overall thermal efficiency remains unchanged
C) Actual thermal efficiency increases by 5%
D) Overall thermal efficiency can rise to 80%

Question 32

In a hydrogen fuel cell commercial vehicle, where is the DC electricity stored?

A) RESS
B) Inverter
C) HVAC unit
D) Traction motor(s)

Question 33

In an HEV equipped with a blended torque transmission (BTT), what is usually providing torque to the wheels at vehicle launch?

A) only the ICE
B) the BTT generator
C) the BTT motor
D) the regenerative brake system

Question 34

Technician A says that a series hydraulic hybrid (SHH) drive options either direct mechanical or full hydraulic motor drive. Technician B says that the Eaton HLA is a parallel hydraulic hybrid (PHH) system. Who is correct?

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

Question 35

Technician A says that the HLA accumulator can be loaded with hydraulic pressures up to 5,000 psi. Technician B says that the Eaton HLA drivetrain uses a reversible hydraulic piston pump/motor. Who is correct?

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

Question 36

Which of the following is true of regenerative braking in an HEV commercial vehicle?

A) Retarding energy is first converted to AC.
B) Retarding energy AC is converted to DC.
C) Retarding energy DC is stored to the RESS.
D) All of the above

Question 37

When is the ICE most likely to be required to mechanically power a HEV drivetrain?

A) At cruise speed
B) At vehicle maximum speed
C) At the moment of launch from standstill
D) While navigating long uphill gradient

Question 38

Which of the following powertrains does not use an internal combustion engine (ICE)?

A) HEV
B) SHH drivetrain
C) PHH drivetrain
D) PEM fuel cell drivetrain

Question 39

Where are the hydrogen cylinders usually located on a fuel cell powered transit bus?

A) On the roof
B) Under the chassis frame
C) In the forward engine compartment
D) In the rear engine compartment

Question 40

What effect does cryo-compression have on the hydrogen that is used to power fuel cells?

A) It reduces its weight.
B) It increases its density.
C) It makes it less flammable.
D) All of the above

Question 41

During which of the following operating modes is the electrical section of a blended torque transmission (BTT) most likely to generate electricity?

A) At vehicle launch.
B) Never, it is a motor
C) During regenerative braking
D) While ascending a steep hill

Question 42

If the ICE failed in an PHEV vehicle with a BTT, which of the following would be true?

A) The vehicle would be stranded
B) The vehicle would run until the RESS power was spent
C) The vehicle would run until the ICE fuel was used up
D) The vehicle would run until the hydrogen fuel was spent