Week #5 - Basic Fuel Systems Flashcards
True or False: DEF is available at most diesel refueling stations.
True
The theory that explains the atomic differences in the three states of matter is known as what?
Kinetic molecular theory
Calculate the stoichiometric requirement of a fuel composed of 84% carbon, 15% hydrogen, and 1% sulfur when combusted in ambient air.
14.96: 1
An injector spring in a hydraulic injector nozzle that is fatigued would likely produce which of the following conditions?
a. Nozzle chatter
b. Lower NOP and advanced injection timing
c. Higher NOP
d. Higher NOP retarded injection timing
b. Lower NOP and advanced injection timing
In which engine position does the crank throw provide the least amount of leverage?
a. 15 degrees ATDC
b. 90 degrees ATDC
c. BDC
d. TDC
d. TDC
True or False: Diesel fuel tends to be more volatile than gasoline.
False
Which of the following solutions would provide the highest level of antifreeze protection?
a. A 100% solution of PG
b. A 100% solution of EG
c. A 50/50 solution of EG and distilled water
d. Pure distilled water
c. A 50/50 solution of EG and distilled water
True or False: EG is always colored green.
False
Which of the following specific gravity values would correspond to that of a typical #2D diesel fuel?
a. 0.840
b. 0.710
c. 1.170
d. 0.970
b. 0.840
Atomized droplets are in a gaseous state.
False
When attempting to cold-start an electronically controlled diesel engine in subzero (lower than -70 degrees C) conditions, which of the following would provide the most help?
a. Smaller than normal fuel droplet sizing
b. Larger than normal fuel droplet sizing
c,. Pushing the accelerator to the floor
d. Substantial advance to injection timing
a. Smaller than normal fuel droplet sizing
True or False: Some water-separator units use a centrifuge to separate water from fuel.
True
True or False: The end products of both an explosion and a combustion reaction are similar.
True
True or False: The laws of thermodynamics dictate that a catalytic reaction must involve a change in the state of the catalyst.
False
True or False: The stoichiometric requirement of a diesel fuel ranges between 14.5:1 and 15.1:1.
True
True or False: All #1D and #2D fuels must be sold with a CN number of exactly 40.
False
True or False: At refueling on the completion of a journey, fuel is steaming in the tanks. This condition is a result of normal operation in some fuel systems.
True
True or False: Injector nozzles used on pre-2007 EUIs and HEUIs use the same operating principles as those on any hydraulic pump-line-nozzle system.
True
The most abundant element found in the known universe is what?
Hydrogen
True or False: The degree of atomization is controlled by managing injection pressure.
True
True or False: Most commercial truck diesel engines use a vane-type transfer pump located in the fuel tank to pump fuel to the transfer pump.
False
True or False: Denser fractions of crude petroleums tend to command higher prices than lighter fractions.
False
True or False: An isochronous governor is normally used to manage a genset.
True
How many protons would a balanced atom of oxygen contain?
8
The atomic number of an element indicates the number of _____ in an atom of the element.
Protons
The smallest particle of a compound that can exist in the free state and retain the chemical identity of the compound is know as a(n) _____.
Molecule
Oxygen has a valence of ____.
2
If a four-stroke cycle engine is run at 1,000 rpm, approximately how many power strokes per second will occur in any one of its cylinders?
17
Nozzle differential ratio is a ratio of:
a. The high-pressure pipe sectional area and the orifii flow area
b. Nozzle seat sectional area and total nozzle sectional area
c. The mechanical spring force and hydraulic pressure
d. The nozzle pressure chamber sectional area and the high-pressure pipe sectional area
b. Nozzle seat sectional area and total nozzle sectional area
True or False: In a current truck dual fuel tanks, fuel pickup tubes are located in each tank.
True
True or False: Nozzle chatter while bench-testing an injector is an indication of a fatigued injector spring.
False
What color is used to denote a DEF fill cap?
Blue
True or False: Diesel fuel can combine with air to form potentially explosive mixtures.
True
As the octane rating value of a gasoline increases, what can be said of its burn rate?
a. It increases
b. It is not affected
c. It decreases
c. It decreases
Besides fuel storage, the fuel tank may play an important role in a high-flow fuel system as a(n):
a. Aerodynamic aid
b. Heat exchanger
c. Fuel heating device
d. Ballast equalizer
b. Heat exchanger
True or False: Most truck engine OEMs recommend adding fuel conditioners to diesel fuel tanks to improve the winter drivability of diesel engines.
False
True or False: Refiners and fuel suppliers seasonally adjust the ignition quality of fuels.
True
The term used to describe a combustion reaction in which the exact proportions of fuel and air are present is ______.
Stoichiometric
True or False: Most electronically managed diesel engines are run at precise stoichiiometric ratios of air and fuel after the engine is at operating temperature.
False
On the typical truck diesel fuel subsystem, which of the following is usually subject to the lowest pressure in the circuit?
a. Primary filter
b. Fuel heater
c. Charging gallery
d. Secondary filter
a. Primary filter
True or False: When servicing fuel filters on a fuel subsystem with a primary and a secondary filter, a transfer-pump-located, hand primer pump can be used to prime both filters.
False
True or False: When diesel fuel is combusted, one of the products of combustion is water.
True
True or False: EHIs using the most common type of piezoelectric actuators should test at resistance values of 0.6 ohms or less.
True
Charging pressure rise is usually directly related to which of the following?
a. Increased rpm
b. Throttle position
c. Engine load
d. Peak power
a. Increased rpm
Which of the following is the correct course of action when a WIF alert is posted to the DDU?
a. Replace the fuel filters
b. Drain the water separator pump
c. Replace the water separator
d. All of the above
b. Drain the water separator pump
True or False: Carbon can be classified as a reactive element.
True
Calculate the stoichiometric requirement of a fuel composed of 84% carbon, 15% hydrogen, and 1% sulfur when combusted in pure oxygen.
3.34: 1
The main reason for filling vehicle fuel tanks before overnight parking is:
a. To minimize fuel evaporation
b. Drivers may forge the next morning
c. To hope cool down onboard fuel
d. To minimize moisture condensation within the tank
d. To minimize moisture condensation within the tank
As the CN value of a diesel fuel increases, what happens to its ignition temperature?
a. It increases
b. It is not affected
c. It decreases
c. It decreases
Which type of injection nozzle would be found on most DI truck diesel engines before 2007?
Multi-orifii
True or False: An explosion is an oxidation reaction that occurs in much less time than what would be described as combustion in an engine cylinder.
True
What type of pumping principle is used by a typical hand primer pump?
Single-acting plunger
True or False: The opening and closing of an EHI are controlled by the ECM.
True
If the fuel tank vent valve on a diesel-powered vehicle is plugged, which of the following would be the likely outcome when running the engine?
a. The engine would run away due to excess fuel
b. The engine would shut down due to fuel starvation
c. The tank would explode
d. The tank would implode
b. The engine would shut down due to fuel starvation
An engine run at a speed exceeding rated, but less than high-idle, speed would be operating:
a. In an overrun condition
b. In the droop curve
c. In the torque rise profile
d. At peak torque
b. In the droop curve
True or False: Drivers are more likely to complain about a lack of power on an engine with a short torque rise profile than one with high torque rise.
True
When nozzle forward leakage is benchchecked, what is being tested?
Ability of nozzle valve seat to seal
True or False: When a hydraulic multi-orifii injector is used in an electronically managed fuel system, nozzle opening and closing are switched hydraulically.
True
When should a diesel engine air filter be changed?
a. When the restriction gauge indicates it is beginning to plug
b. At every engine wet service
c. Every 6 months
d. Every time the oil filter is changed
a. When the restriction gauge indicates it is beginning to plug
A secondary filter is located:
a. In the fuel rail
b. In the return gallery
c. On the charge side of the transfer pump
d. Upstream from the transfer pump
c. On the charge side of the transfer pump
Approximately how much does 100 U.S. gallons of #2D diesel fuel weigh?
730 lbs.
The most abundant element found in the earth’s crust is what?
Oxygen
True or False: Most diesel engines are managed to run at rich fuel-to-air ratios.
False
True or False: A governor is designed to derate engine fueling as altitude increases.
True
The correct instrument to use for checking for the admission of air to a fuel subsystem is what?
Diagnostic sight glass
Which of the following types of injectors would be best suited to multipulse injection?
a. EHI with solenoid actuator
b. EHI with piezoelectric actuator
c. Hydraulic poppet
d. Hydraulic multi-orifii
b. EHI with piezoelectric actuator
True or False: The stoichiometric requirement of a gasoline combusted in air at sea level must be precisely 14.7:1.
False
True or False: At refueling on the completion of a journey, fuel is steaming in the tanks. Such a condition can be a result of running the tanks low on fuel in a high-flow fuel system.
True
True or False: Diesel fuel CN is likely to degrade more quickly during the winter than in the heat of summer.
False
Replacing a single high-pressure injection pipe on a multicylinder engine by one of greater length would likely have what effect on injection timing in the affected cylinder?
a. None
b. Decrease the fuel pulse width
c. Advance
d. Retard
d. Retard
True or False: Hydrogen is an inert element.
False
What is the minimum CN requirement of #1D or #2D on-highway diesel fuel?
40
A cubic centimeter of a typical diesel fuel would require approximately what volume of air at sea level to completely oxidize it?
12,000 cc
The precise control of injected fuel quantity is known as what?
Metering
Excessive fuel returned into the leak-off lines from a set of hydraulic injector nozzles is an indication of:
a. wear in the nozzle seat
b. a weak injector spring
c. nozzle seat leakage
d. wear in the nozzle-body-to-nozzle-value fit
d. wear in the nozzle-body-to-nozzle-value fit
What type of fuel injector nozzles are required on almost all on-highway diesel engines that are certified for EPA 2010?
Electrohydraulic
Which of the following engine lubricants must be used if an engine is equipped with a DPF?
a. API CJ-4
b. API CI-4
c. Any synthetic lubricant
d. Any biodiesel lubricant
a. API CJ-4
The temperature at which a fuel evaporates sufficient flammable vapor to momentarily ignite when a flame is brought close to its surface is known as:
a. boil point
b. flash point
c. fire point
b. flash point
True or False: Because fuel is heavier than water, fuel can easily be separated from the water because it always settles under the water.
False
An ideal fuel system manages fueling to produce peak cylinder pressure at which location on the power stroke to produce optimum performance on any given engine cycle?
a. 15 degrees ATDC
b. 90 degrees ATDC
c. BDC
d. TDC
a. 15 degrees ATDC
What is the distinguishing feature of a VCO nozzle?
The sac is eliminated
True or False: An LS governor is designed to produce accelerator response close to that of an automobile throttle.
True
When the term ‘pilot injection’ is used to describe the initial shot of fuel in a multipulse injection system, which of the following best describes its function?
a. It cools the piston crown
b. It initiates the flame front for the main pulse
c. It doses the diesel particulate filter
d. It lubricates the cylinder walls
b. It initiates the flame front for the main pulse
True or False: The fastest way to break in a diesel engine is to add a charge of aftermarket break-in solution to the engine oil.
True
In what position through the power stroke is crank throw leverage at its maximum?
a. 15 degrees ATDC
b. 90 degrees ATDC
c. BDC
d. TDC
90 degree rod-to-throw angle
What quantity of oil does the distance from the top to the bottom of the crosshatch area on a typical heavy-duty diesel engine represent?
4.0 quarts (3.8 L)
Given unlimited fuel, a diesel engine may accelerate at a rate up to:
a. 1,000 rpm per second
b. 60 rpm per second
c. 120 rpm per minute
d. 120 rpm per second
a. 1,000 rpm per second
True or False: Some mulipulse diesel fuel injection systems can break up an injection pulse into seven separate injection events in one cycle.
True
True or False: If a transfer-pump-located, hand primer pump is used to prime the secondary filter after installation, it reduces the chances of dirt contamination downstream from the filter.
True
What units are typically used to express ‘duty cycle’ in electronically managed diesel engines?
a. Milliseconds
b. Microseconds
c. Microns
a. Milliseconds
How many electrons would a balanced atom of carbon contain?
6
True or False: Hydraulic injector nozzles are designed so that the pressure required to open the nozzle valve is greater than the pressure required to hold it open.
True
Which of the following statements correctly describes air?
a. A compound of nitrogen, oxygen, and inert gases
b. A molecule of nitrogen, oxygen, and inert gases
c. A mixture of nitrogen, oxygen, and inert gases
d. An element of nitrogen, oxygen, and inert gases
c. A mixture of nitrogen, oxygen and inert gases
The lowest temperature at which a diesel fuel can be pumped through a fuel system is known as what?
Pour point
Which of the following diesel fuel additives is a commonly used cetane improver?
a. Cyclohexanol nitrate
b. Isopropyl alcohol
c. Kerosene
d. Kerogen
a. Cyclohexanol nitrate
What acronym is commonly used to display ‘duty cycle’ on electronic service tools (ESTs)?
a. IRT
b. DC
c. PWM
d. PW
d. PW
The temperature at which a diesel fuel begins to form paraffin wax crystals is known as what?
Cloud point
The correct instrument for testing the low-pressure side of most fuel subsystems for inlet restriction is what?
Hg manometer
Proportionately, the largest ingredient in an in-engine cylinder, combustion reaction is _____.
Nitrogen
Current diesel fuel formulated for on-highway use and classified as ULS is required to have what maximum sulfur content?
0.0015%
True or False: Carbon dioxide results from burning diesel fuel.
True
True or False: Diesel engine fuel tank caps are fitted with two-way valve that permits both fuel vapor seepage and air admission to the tank.
False
Combustion in an engine cylinder that takes place with more than one flame front is correctly known as _____/
Detonation
Which type of fuel charging/transfer pump is more commonly used y today’s electronically managed engine/fuel systems?
Gear pumps
True or False: A high-speed diesel engine given unlimited fuel will accelerate to self-destruction.
True
When injector back leakage is benchchecked, what is being tested?
Valve-to-body clearance
True or False: PG is always colored red.
False
Setting the injector NOP value in hydraulic injector nozzles is accomplished by:
a. an adjusting screw.
b. Adding or subtracting shims
c. neither a nor b
d. both a and b
d. both a and b
True or False: Gear pumps are of the positive displacement type.
True
The correct instrument for testing fuel subsystem charging pressure is what?
Accurate pressure gauge
A VS governor is capable of increasing and decreasing fuel quantity per cycle without moving the accelerator pedal.
True
True or False: EHI injector nozzles using solenoid actuators should test at resistance values of 1 ohm or less.
True
Which two factors define the emitted droplet sizings from a nozzle assembly?
a. Loan an rpm
b. Injection pressure and orifice size
c. Cylinder pressure and crank angle
d. Accelerator position and governor
b. Injection pressure and orifice size
True or False: Hydraulic injector nozzles use a soft value NOP.
False
If an additive were required to prevent freeze-up of a fuel crossover pipe, which of the following would be the preferred option?
a. Add 8oz. (250 cc) of cetane improver to the tanks
b. Add 8oz. (250 cc) of gasoline to the tanks
c. Add 8oz. (250 cc) of methyl hydrate to the tanks
d. Add 8oz. (250 cc) of fuel conditioner to the tanks
c. Add 8oz. (250 cc) of methyl hydrate to the tanks
Which of the following is another way of stating the NOP specification?
a. Peak pressure
b. Popping pressure
c. Residual line pressure
d. Not operating properly
b. Popping pressure
True or False: When governed high-idle speed is increased in an on-highway engine, an increase in brake horsepower is a more likely result than a decrease.
True
True or False: After NOP, the nozzle line pressure steadily decreases until the nozzle closes at the end of the injection pulse.
False
True or False: The presence of water in the fuel subsystem can usually be detected by a WIF sensor.
True
Rhythmic fluctuation in engine rpm is known as _____.
Hunting
Which of the following would best describe the color of DEF?
a. Red
b. Amber
c. Blue
d. Clear
d. Clear
When an engine is rapidly accelerated and momentarily exceeds the nominal high-idle speed, the condition is known as _____.
Overrun
True or False: #2D usually has more heat energy than a #1D fuel.
True
True or False: A catalyst is a substance that enhances or enables a chemical reaction without itself undergoing any change.
True
True or False: Plunger pumps are positive displacement.
True
Which of the following factors does most to prevent secondary injections?
a. Nozzle differential ratio
b. The nozzle sac
c. The pressure chamber sectional area
d. Pressure wave reflection
d. Pressure wave reflection
Most diesel engine OEMs recommend that injectors be installed into the cylinder head injector bore:
a. coated with engine oil
b. coated with lubriplate
c. coated with Never-Seize
d. dry
d. dry
Which of the following resistance values indicates a typical within-specification value for a current EHI solenoid actuator?
a. 1,000 ohms
b. 10 ohms
c. 5 ohms
d. 1 ohm
d. 1 ohm
True or False: Some older dual fuel tanks used a single pickup tube located in one of the tanks that were connected by a crossover pipe.
True
Which of the following best describes the term ‘octane rating’ when applied to a fuel?
a. Ignition temperature
b. Antiknock resistance
c. Burn rate
d. Volatility
b. Antiknock resistance
DEF can be obtained from most manufacturer dealerships.
True
Which of the following components would be more likely to fail if LS fuel were used instead of ULS in a highway diesel engine manufactured after 2007?
a. Selective catalytic reduction (SCR) system
b. NOx reduction catalyst
c. Exhaust gas recirculation (EGR) circuith
d. Diesel particulate filter (DPF)
d. Diesel particulate filter (DPF)
Multipulse diesel fuel injection can be hard on powertrain components because it produces spiked cylinder pressures.
False
True or False: A high injector back leakage rate is an indication of excessive nozzle valve-to-nozzle body clearance.
True
True or False: An isochronous governor could be used on a vehicle engine providing it had a fluid clutch.
False
True or False: #2D diesel fuel will, in most cases, produce slightly better fuel mileage from a highway truck engine than a #1D fuel.
True
True or False: The water in fuel tanks can be detected using a probe and water detection paste.
True
