Deck 38: Natural Gas, Propane, and Biodiesel Fuels

Question 1

Which of the following operating conditions is the least suitable for B100 biodiesel fueling of a current diesel engine application powering a truck?

A) Linehaul
B) LTL (less than load/ pick-up and delivery)
C) High ambient temperature
D) Low ambient temperature

Answer 1

Low ambient temperature

Question 2

Technician A says that the fuel specification B5 describes a fuel that is 95% petroleum based cut with 5% biodiesel. Technician B says that most engine OEMs do not approve of the use of biodiesel cuts in their engines. Who is correct?

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

Answer 2

Technician A only

Question 3

Which of the following industrial processing methods is currently used to yield hydrogen from water?

A) distillation
B) cold temperature fractioning
C) electrolysis
D) catalytic cracking

Answer 3

electrolysis

Question 4

When biodiesel is used to fuel commercial vehicles which US federal standard must the fuel comply with?

A) J1939
B) J1667
C) ASTM 975
D) ASTM 6751

Question 5

Technician A says that it is likely that biodiesel will replace petroleum base diesel fuel within the next decade because of its lower emissions. Technician B says that all ASTM 6751 biodiesel has a yellow tint. Who is correct?

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

Question 6

Which of the following fuels meets the ASTM 975 standard for highway diesel fuels?

A) Renewable Diesel
B) Propane
C) Alcohol
D) biodiesel

Question 7

Technician A says that B100 standard biodiesel has better cold climate handling properties than B20. Technician B says that B20 standard biodiesel produces generally lower emissions than current petroleum stock diesel fuels. Who is correct?

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

Question 8

Technician A says that a major disadvantage of using B100 biodiesel as a fuel on North American highways is its high pour point temperature. Technician B says that a disadvantage of using biodiesel cuts as fuels is faster fuel degradation than on equivalent 100% petroleum sourced diesel fuel. Who is correct?

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

Question 9

Technician A says that when compressed natural gas (CNG) is used to fuel a modified diesel engine, a means of igniting the fuel charge must be provided. Technician B says that propane does not auto-ignite in a compression-ignition engine. Who is correct?

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

Question 10

When diesel fuel is used as the pilot in a dual diesel/CNG fuel system, what role does the diesel fuel play?

A) ignition agent
B) lowers emissions
C) reduces particulate matter
D) increases engine output power

Question 11

Technician A says that hydrogen can be reformed from natural gas(NG).. Technician B says that hydrogen does not appear naturally in its elemental form on Earth. Who is correct??

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

Question 12

If the same volume-sized container of each of the following fuels was to be used, which would allow you to travel furthest using today's technologies?

A) Hydrogen
B) Propane
C) Gasoline
D) Diesel fuel

Question 13

Technician A says the best way to avoid rapid fuel degradation problems in biodiesel cuts is to routinely treat it using biocides. Technician B says that when biodiesel is suspected to be under bacterial attack, shocking the fuel with biocides may eliminate the problem. Who is correct?

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

Question 14

Technician A says that when B20 fuel in a highway truck fuel tank appears greenish in color, it should be discarded. Technician B says that the B15 fuel in a highway truck fuel tank has a strong septic tank odor and that treating it with kerosene may recover it. 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 West Coast drayage trucks tend to run on NG fuel. Technician B says that the City of Los Angeles currently uses no diesel power in its entire transit fleet. Who is correct?

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

Question 16

Which of the following companies specializes in converting diesel fueled engines to NG fueling?

A) Cummins
B) Mack Trucks
C) Caterpillar
D) Westport Innovations

Question 17

Which OEM has optioned dimethyl ether (DME) fuel engines ?

A) DTNA
B) Volvo Mack
C) Paccar
D) Navistar

Question 18

Technician A says that biodiesel has greater resistance to water absorption than petroleum base diesel fuel. Technician B says that biodiesel has greater resistance to biological attack than petroleum base diesel fuel giving it a longer shelf life. Who is correct?

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

Question 19

Technician A says that biodiesel burns more cleanly with zero sulfur emissions than equivalent petroleum base diesel fuels. Technician B says that biodiesel has higher calorific value producing better fuel economy than petroleum base diesel fuel. Who is correct?

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

Question 20

In which geographical area does biodiesel have the most acceptance?

A) California
B) North Dakota
C) Northeast
D) Alaska

Question 21

Technician A says that when biodiesel is used in place of petroleum base diesel fuel engine power is increased by approximately 10%. Technician B says that HC emissions are reduced when biodiesel is used as an alternative to diesel fuel. 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 says that LNG is stored in liquid form on vehicles using the fuel. Technician B says that CNG is stored in gaseous form in vehicles using the fuel. Who is correct?

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

Question 23

Technician A says that some OEMs have abandoned manufacturing NG fueled engines because of the difficulty in meeting EPA 2010 NOx emissions standards. Technician B says that a problem in using NG as a fuel, is that carbon dioxide emissions tend to greatly increase. Who is correct?

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

Question 24

What is biomethane sourced from?

A) corn
B) soy
C) beet
D) garbage

Question 25

What is used to ignite a NG fuel charge in the engine cylinder

A) glow plug
B) spark
C) diesel fuel pilot pulse
D) any of the above

Question 26

What pressure must compressed natural gas (CNG) be stored at in vehicle fuel tanks?

A) ambient pressure
B) 230 psi (16 bar)
C) 3000 to 4500 psi (200 to 310 bar)
D) at whatever the required injection pressure is

Question 27

Which of the following best describes the type of vehicle fuel tank required to store LNG?

A) cryogenic
B) extreme high pressure
C) spherical
D) extreme low pressure

Question 28

What pressure must liquified natural gas (LNG) be stored at in vehicle fuel tanks

A) ambient pressure
B) 230 psi (16 bar)
C) 3000 to 4500 psi (200 to 310 bar)
D) injection pressure

Question 29

What must be done to a vehicle LNG fuel before it is delivered to the fuel injection apparatus?

A) heated and vaporized
B) cooled and pressurized
C) cooled and liquified
D) heated and pressurized

Question 30

Technician A says that natural gas (NG) is lighter than air. Technician B says that NG quickly disperses when released to atmosphere making it relatively safe. Who is correct?

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

Question 31

What temperature is LNG stored at in vehicle cryogenic fuel tanks?

A) ambient temperature
B) 32 degrees Fahrenheit (0 degrees Celsius)
C) 0 degrees Fahrenheit (-17 degrees Celsius)
D) -220 degrees Fahrenheit (-140 degrees Celsius)

Question 32

Technician A says that engines fueled with NG require special crankcase lubes. Technician B says that NG fueled engines require more frequent service intervals than equivalent diesel fueled engines. Who is correct?

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

Question 33

Technician A says that the Westport LNG high pressure direct injector (HPDI) uses piezo actuators. Technican B says that the Westport HPDI is a dual fuel, electronically-controlled, common rail injector. Who is correct?

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

Question 34

Technician A says that the Westport CNG-DI Mono injector is designed to inject liquefied fuel. Technician B says that the Westport CNG-DI Mono injector is designed to inject gaseous fuel. 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 Westport CNG-DI Mono injector is designed to inject NG but can also be used to inject hydrogen. Technician B says that the Westport CNG-DI Mono injector incorporates a diesel pilot capability to ignite the fuel charge. Who is correct?

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

Question 36

What is used to ignite the gas charge in a Westport LNG engine using HPDI injectors?

A) hot surface
B) glow plug
C) spark
D) diesel fuel pilot

Question 37

What is the usual method of igniting the fuel charge when a Westport CNG-DI Mono injector is used to deliver the gas charge?

A) continuously operating glow plugs or spark plugs
B) glow plugs energized at start-up only
C) diesel fuel
D) compression temperatures

Question 38

Technician A says that when a diesel engine is adapted for LNG fueling using Westport HPDI injectors, a special camshaft is required. Technician B says that Westport HPDI injectors are capable of multipulse fueling events. Who is correct?

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

Question 39

Technician A says that a disadvantage of propane as a fuel is that its pricing fluctuates along with petroleum fuel pricing. Technician B says that an advantage of propane compared with NG is that it auto-ignites at diesel engine compression temperatures and pressures. Who is correct?

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

Question 40

What is the time period required for electrically charging the coil in a CNG spark-ignited (SI) engine known as?

A) ?Pulse duration
B) ?Spark retard
C) ?Spark advance
D) ?Dwell

Question 41

Which of the following would properly describe the type of SI system used on a current CNG fuel system on commercial vehicle applications? ?

A) ?Capacitive discharge ignition (CDI)
B) ?Breakerless ignition
C) ?Coil-on-plug ignition (CPI)
D) ?Distributor ignition

Question 42

What is the primary input reference signal to the ECM responsible for triggering spark delivery to a CPI system on a commercial vehicle NG engine?

A) Camshaft position sensor (CPS)
B) Engine temperature sensor (ETS)
C) Road speed sensor (RSS)
D) Oil pressure sensor (OPS)

Question 43

What is the likely performance outcome of a defective coil pack in a CPS SI system used in a current CNG engine??

A) Misfire
B) ?Increased fuel consumption
C) ?Dead cylinder
D) ?All of the above

Question 44

?When waste spark ignition is used on an engine, when is the waste spark delivered to the engine cylinder?

A) ?Piston at TDC on compression stroke
B) ?Piston at TDC on exhaust stroke
C) ?Piston at BDC on power stroke
D) ?Piston at BDC on intake stroke

Question 45

Technician A says that post-2010 NG fueled commercial engines must be equipped with a DPF in the exhaust gas aftertreatment circuit. Technician B says that post-2010 NG fueled commercial engines are normally equipped with passive reduction and oxidation catalysts in the exhaust system. Who is correct??

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

Question 46

Technician A says that when a CNG commercial vehicle is serviced in a facility not specifically designed for NG vehicles, 50% of the roll-up doors must be raised at least 12-inches (25cm) from the ground. Technician B says that when a CNG commercial vehicle is serviced in a facility not specifically designed for NG vehicles, the extraction and ventilation system must be turned on a be capable of exchanging 5 times the total shop volume of air per hour. Who is correct??

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

Question 47

Which of the following are indications that oil is present within the fuel system of an NG fueled commercial engine??

A) ?Hard starting
B) ?Rough idle
C) ?Hesitation under load
D) ?All of the above