otc_-_deisel_electrical_det-106_20171012120006 Flashcards
When an incandescent light bulb is energized in an electrical circuit, what is electrical energy converted to?
heat and light
What is the function of a headlamp dimmer switch?
switches headlamps between separate low-and high-beam circuits
What type of headlight fires an arc through gas to produce light energy?
HID
Which of the following best explains the construction of a halogen headlamp element?
tungsten filament encased in a quartz envelope
How much voltage is required to sustain the arc in a typical HID headlamp assembly?
around 85 volts
Which of the following best defines light energy?a. heat b. photons c. electrons d. protons
photons
Which of the following would be used to switch turn lights on a truck chassis?a. stalk switch b. headlamp switch c. brake pressure switch d. toggle switch
stalk switch
How many contacts are in a typical tractor-to-trailer electrical connector?
seven
What color code is used for the brake light circuit in a truck trailer electrical connector?
red
When truck and trailer clearance lights and headlamps seem to burn out at a high rate, which of the following would be a required step in troubleshooting?a. voltage losses in ground circuit b. battery state of charge c. battery surface charge d. charging system voltage regulator
charging system voltage regulator
What governs highway truck exterior lighting standards in North American trucks?
FMVSS 108
In a standard SAE relay, which of the following is normally open (NO)?a. 7 b. 4 c. 5 d. 3
5
In an older standard SAE relay, what pair of terminals energizes the coil circuit?
85 and 86
The headlights on a truck with electromechanical controls and circuit breaker protection continuously illuminates for a short period and then cut out. Technician A says that if the circuit breaker is a type 1, replacing it with a type 2 should repair the problem. Technician B says that the problem is likely caused by a malfunction in a type-2 circuit breaker. Who is correct?
Neither A nor B
Technician A says that on a standard SAE relay, terminal 3 is always the common terminal. Technician B says that in a standard SAE relay, the coil circuit must be energized to close the normally open 5 terminal. Who is correct?
Both A and B
What is the maximum acceptable total voltage drop across all of the terminals and cables on the insulated side of a cranking circuit?
0.5 volt
Technician A says that a corroded light unit terminal could result in an increased voltage drop across the terminal. Technician B says that a corroded light unit terminal could result in heat at the terminal. Who is correct?
Neither A nor B
Technician A says that a disadvantage of using LEDs as stoplights is that when the circuit is switched on, they illuminate at a slower speed than incandescent bulbs. Technician B says that xenon headlamps are a disadvantage in trucks because they have a shorter service life than halogen bulbs. Who is correct?
Neither A nor B
What type of filament is used in a halogen headlight?
tungsten
Technician A says that HID headlamps consume more electrical power than equivalent halogen headlamps. Technician B says that HID headlamps are brighter and their blue light is more similar to natural sunlight than that of halogen lamps. Who is correct?
Technician B only
What EST is used to read flash codes?
dash diagnostic lights
The appropriate EST for performing a resistance test on a potentiometer-type TPS isolated from its circuit is what?
DMM
What is the correct means of electronically coupling a HH-EST with a truck chassis ECM?
chassis data connector
When resistance and continuity tests are made on electronic circuit components, the circuit being tested should be:a. energized b. open c. closed
open
DMM test lead resistance should never exceed:a. 100 ohms b. 10 ohms per inch c. 1.0 ohm a. 0.2 ohm
1.0 ohm
What is the output (signal) of a pulse generator rotational speed sensor measured in?
V-AC
Which of following cannot usually be performed by a generic HH-EST?a. proprietary data programming b. snapshot testing c. customer data programming d. erase historic fault codes
proprietary data programming
Which of the following procedures cannot be performed using a PC and the OEM software?a. solenoid cycle tests b. permanently erase active fault codes c. customer data programming d. erase historic fault codes
permanently erase active fault codes
Which of the following methods is commonly used to upgrade the software on handheld ESTs?a. replace the RAM chip b. reprogram the software cartridge from a mainframe b. upgrade the cartridge PROM chips or cards d. Replace the docking head
upgrade the cartridge PROM chips or cards
Which FMI should be displayed when reading an open TPS circuit?
5
How many counts of resolution can be displayed by a 41/2-digit DMM?
19,999
The specification that indicates how fine a measurement can be made by a DMM is known as what?
resolution
When a DMM is set to read AC, which is the term used to describe the averaging of potential difference to produce a meter reading?
root mean square (rms)
Which port on an HH-EST data connector is used to connect the printer?
RS-232 port
What components are inserted into terminal sockets to enable testing by KMM probes and minimize physical damage?
terminal dummies
Which electrical voltage value does a DMM output when in diode test mode?
0.6V
Technician A states that the accuracy of an analog meter is usually no better than 3 percent. Technician B states that most DMMs have an accuracy factor that is within 0.1 percent of the reading. Who is correct?a. neither A nor B b. both A and B c. Technician A only Technician B only
Both A and B
What is the component called that can be safely inserted into electronic circuits so that they can be tested without interrupting them?
breakout box
Technician A states that using the snapshot test mode when using a handheld reader/programmer to troubleshoot an intermittently occurring fault code will help identify the conditions that produced the code. Technician B states that snapshot test mode can only analyze a historic code. Who is correct?a. neither A nor B b. Both A and B c. Technician B only d. Technician A only
Technician A only
When verifying the signal produced by a potentiometer-type TPS, the DMM test mode selected should be, what?
V-AC
Describe the difference between an active code and a historic code
An ACTIVE code exists at the time of viewing: A HISTORIC code is INACTIVE at the time of viewing and is logged in memory
What is meant by the term GUI? Give some examples.
A GUI is a graphical user interface: its best example is in the pictorial ICONs used in Widows, and Mac software.
What is meant by the term networking?
The term NETWORKING is used generally to refer to two or more computer systems that can communicate with each other. On a truck, the data bus or backbone is the networking medium. The Internet is one means that enable PCs to network.
Which of the following PC components would be usually described as a peripheral?a. system housing b. hard disk drive c. CPU d. Printer
Printer
In a PC is to be networked to the Internet or an OEM data Hub, which of the following devices is usually required? a. a CD drive b. a digital camera c. speakers d. a modem
a modem
Which of the following J1587 identifiers is equivalent to a J1939 suspect parameter number (SPN)?a. SA b. FMI c. PID a MID
PID
Technician A says that a J1939 SA is a module with an address on the data bus. Technician B says that J1587 FMIs are identical in number to J1939 FMIs. Who is correct?
Technician A only
Which of the following is the J1939 equivalent of the J1587 MID?a. SPN b. SA c. FMI d. PGN
SA
What color is the 2013 J1939 data connector?
Green
Technician A says that the post-2013 J1939 data connector is backward compatible with pre-2013 data connectors. Technician B says the F-pin on a post-2013 J1939 data connector is smaller than that on a pre-2013 data connector. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. neither A nor B
Both a and B
What is the tool of choice to accurately check the inlet restriction of a dry air filter?
water-filled manometer
What is a typical maximum specified inlet restriction for an air filter on a turbocharged diesel?
25 inches H2O restriction
Which of the following types of air filters has the highest filtering efficiencies?a. Centrifugal precleaners b. Dry, positive c. Dry, non-positive d. Oil bath
Dry, positive
Which of the following should be performed first when checking an engine that produces black smoke under load?a. Injection timing b. Air filter restriction test c. Plugged DPF d. Fuel quality by chemical lab analysis
Air filter restriction test
Which of the following best describes the intended function of a C-EGR system on a diesel engine?a. It assists the turbocharger in boosting intake pressure b. It increases engine breathing efficiency c. It dilutes the intake charge with cooled dead gas d,. It preheats the intake charge to the cylinder
It dilutes the intake charge with cooled dead gas
What best describes the function of a wastegate in a current turbo-boosted diesel engine?
Allows exhaust gas to bypass the turbine
When series turbocharging is used on a current diesel engine, which of the following should be true?a. Twin turbos are arranged in parallel b. Intake air must pass through the turbine housing of both turbos c. Exhaust gas must pass through the turbine housing of both turbos c. The VG actuator is in series with the EGR mixer
Exhaust gas must pass through the turbine housing of both turbos
What is the critical flow area managed by a VG turbo using a variable nozzle operating principle?
Turbine volute
To produce peak manifold boost from a VN-type turbocharge, which of the following should be true?a. Wastegate is fully closed b. Wastgate is fully open c. Vanes are in the nearly closed position d. Vance are in the fully open position
Vanes are in the nearly closed position
The constant geometry turbocharger used in a highway diesel engine with turbo corresponding is usually designed to produce optimum efficiency at which rpm?
Rated speed and load
Technician A states that a dry air filter functions at optimum entrapment efficiency when it is new and that by the time it requires replacing, it has lower filtering efficiencies. Technician B states that oil bath filters are seldom used with today’s highway diesel engines because they have low filtering efficiencies. Who is correct?a. Technician A b. Technician B c. Both A and B d. Neither A nor B
Technician B only
Technician A states that turbo-compounded diesel engines such as the DDC DD15 use CG turbos to supply boost air to the intake manifold. Technician B states that turbo compounding allos the turbo to directly contribute drive torque to the engine drivetrain by means of reduction gearing. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Both A and B
Technician A states that the term “manifold boost” is used to describe breathing on a turbocharged engine. Technician B states that turbine speeds on truck diesel engines can exceed 100,000 rpm. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Both A and B
Technician A states that using a light bulb inside an air filter element is a reliable means of determining whether the filter is plugged. Technician B states that air filters are vest left untouched between service intervals unless the filter restriction gauge indicated an out-of-specification reading. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Technician B only
Technician A states that the first item to be checked when an engine produces black smoke should be the air filter inlet restriction gauge. Technician B states that whenever an engine produces black smoke, the air filter should automatically be changed. Who is correct?
Technician A only
Which of the following methods would identify the location of a hole or tear in an air filter element?a. Air inlet restriction gauge b. Lightbulb test c. Regulated air pressure test d. Manometer test
Lightbulb test
When is a diesel engine turbocharger capable of highest rotational speeds?
When rejected heat is greatest
Which of the following components would be located in a diesel exhaust gas aftertreatment canister?a. SCR b. DPF c. Oxidation converter d. Any or all of the above
Any or all of the above
Which of the following best describes the function of a VG turbocharger?a. It reroutes NOx back into the engine cylinders b. It reroutes EGR gas into the DPF c. It behaves like a large turbocharger when engine load is high d. It behaves like a small turbocharger when engine load is high
It behaves like a large turbocharger when engine load is high
Technician A states that the function of a turbocharger wastegate is a divert exhaust gas around the turbine directly into the exhaust system. Technician B states that a wastgated turbocharger can improve turbine efficiencies at lower loads and rpms. who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Both A and B
Who invented the first heat engine?
Hero
Which of the following properly describes the first heat engine?a. Internal combustion b. Reaction turbine c. Two-stroke cycle d. Four-stroke cycle
Reaction turbine
Who invented the term horsepower?
Watt
Who built the world’s first useful steam engine?
Savery
Who designed the first centrifugal governor?
Watt
In what year did Diesel patent his compression ignition engine?
1892
Who patented the first high-pressure liquid fuel injection pump for a diesel engine?
Bosch
Who is known as the “father of the highway diesel engine”?
Cummins
What are the U.S. inventors Eckert and Mauchly known for?
The first electronic digital computer
The world’s first automobile was built by who?
Cugnot
Calculate the brake power of an engine producing 1,150 lb-ft. of torque at the flywheel when it is turning at 2,000 rpm.
438 BPH
Use the PLANC formula to calculate the indicated power of a six-cylinder, fourstroke cycle engine run at 1,800 rpm using the following data:Stroke: 6.0 inchesBore: 5.5 inchesMEP: 220 psi
428 BHP
Which of the following is required to produce peak torque in a diesel engine?a. Peak volumetric efficiency b. Peak mechanical efficiency c. Peak brake power d. Peak cylinder pressure
Peak cylinder pressure
In most hydromechanical fuel systems, when maximum engine rpm is increased, the engine brake power potential will also increase. True or False?
True
Which of the following statements helps explain why an engine develops peak brake power at a higher rpm than peak torque?a. Volumetric efficiency is better at high rpm b. There is more time for combustion c. More power strokes per second occur d. Cylinder pressures are highest
More power strokes per second occur
Which of the following is true of an engine described as having high torque rise when comparing it with its standard version with the same nominal rated power?a. It will provide a wider operating rpm range b. It will be more fuel efficient c. It will produce higher brake power d. It will have a higher maximum speed
It will provide a wider operating rpm range
A group of cyclists all weighing 175 lbs (80 kg) and riding on bicycles of equal weight ride a 6.4-mile (10-kilometer) race and all finish it. Which of the cyclists has performed the most work?a. The winner b. The loser c. All have performed equal work
All have performed equal work
Usable power at the flywheel of an engine is know as what?
Brake power
When engine power is calculated rather than tested, it is know as what?
Indicated power
Which of the following expresses 1 HP correctly?a. 550 lb-ft. of work per second b. 5,252 lb-ft. of work per minute c. 33,000 lb-ft. of work per second
550 lb-ft. of work per second
Convert a torque value of 25 lb-ft. into Newton-meters
33.9
A Cummins ISX 11.9 liter engine, programmed to 330 HP, produces a peak torque value of 1,350 lv-ft. at 1,300 rpm. Convert the torque value to Newton-meters.
1,830 N.m
A Detroit Diesel DD16 is rated at 600 HP. Express this in kilowatts.
448 kW
A Navistar MaxxForce 13 produces 355 kW of power at 1,800 rpm. Convert the kW to an HP value.
475 HP
When comparing truck engine brake power measured at the flywheel to that measured at the drive wheels, which one of the following should be true about brake power?a. There is no difference if the transmission and drive carrier are functioning properly.b. Power at the flywheel exceeds that at the drive wheels by 20% to 25%c. Power at the wheels exceeds that at the flywheel by 10% to 25%d. Power can only be measured at the drive wheels
Power at the flywheel exceeds that at the drive wheels by 20% to 25%
Which of the following engine conditions would be the likely cause of a tensile failure of a connecting rod?a. Prolonged lug downb. Prolonged engine idlingc. Engine overspeedd. High cylinder pressures
Engine overspeed
Which of the following is a disadvantage of an articulating piston assembly when compared to an aluminum alloy trunk piston?a. Piston slap controlb. Highest possible location of an upper ring groovec. Service lifed. Increased tensile loading on the connecting rods
Increased tensile loading on the connecting rods
Where would a Ni-Resist insert be located?
Upper ring belt, aluminum trunk position
Under which of the following conditions would a piston ring seal more effectively?a. High cylinder pressuresb. Low cylinder pressuresc. High engine temperaturesd. Low engine temperatures
High cylinder pressures
A crankshaft has a fracture failure that appears to have initiated at a throw journal oil hole. Which of the following would be the most likely cause?a. A failed vibration damperb. A spun rod bearingc. A broken main capd. Excessive cylinder pressure
A failed vibration damper
Which of the following journal surface hardening methods would provide the highest machinability margin?a. Induction hardeningb. Flame hardeningc. Nitriding d. Shot peening
Induction hardening
Rod and main journal bearing clearances are properly measured with what?
Plastigage
What type of piston is favored by diesel engine OEMs in post-2007 products?
Forged steel trunk
When observing a disassembled engine, the outer crown edges of all six pistons show signs of melting and erosion. This could be cause by what?a. Fuel with high sulfur contentb. Advanced timingc. retarded timingd. a dribbling injector
Advanced timing
Which of the following types of pistons use brushingless pin bosses?a. Aluminum alloyb. Crossheadc. Monothermd. Ferrotherm
Monotherm
What would be the consequence of a misdirected piston oil cooling jet?a. Overheated engine lubeb. Fuel in the lubec. Low oil pressured. Torched piston
Torched piston
Technician A states that keystone rings are most common in current diesel engines. Technician B states that keystone connecting rods have a wedge-shaped big end. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Technician A only
What should be used to install piston rings onto a piston?
A ring expander
Which of the following operating modes would be more likely to result in a compressional failure of a connecting rod?a. Prolonged low idle runningb. Prolonged high idle runningc. Hydraulic lock caused by head gasket failured. Overspeeding engine
Hydraulic lock caused by head gasket failure
Which of the following would be the more likely outcome of running an engine with a failed vibration damper?a. Crankshaft failureb. Camshaft failurec. Increased fuel consumptiond. Increased cylinder blowby
Crankshaft failure
Into what area of a Mexican hat combustion chamber are the injected droplets of fuel directed?
Crater
The upper face of a piston assembly is called what?
Crown
Technician A states that a cam ground piston is circular when cold and expands to an elliptical shape at operating temperature. Technician B states that the reason the cam ground piston is elliptical when cold is to accommodate the thermal expansion of the greater mass of material at the piston boss as it is raised to operating temperature. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Technician B only
The piston crown design most commonly used by OEMs in today’s highway diesel engines is the:a. Barrel faceb. Mexican hatc. Mann typed. Dished
Mexican hat
What term is used to describe the cylinder volume between the piston upper compression ring and its leading edge?
Headland volume
Which of the following is true of a CFA piston?a. The ring belt operates at higher temperaturesb. It is used only on articulating pistonsc. It is type of Ni-Resist insertd. The ring belt reinforcement insert extends up into the leading edge of the piston
The ring belt reinforcement insert extends up into the leading edge of the piston
When crankshaft thrust surfaces are reground, which of the following would be true?a. The thrust washers must be shimmed.b. The thrust washers must be machined to smaller dimensionc. Undersize thrust bearings are requiredd. Oversize thrust bearings are required
Oversize thrust bearings are required
Technician A states that main bearing shells are usually interchangeable and may be installed in either the upper or lower position. Technician B states that the main bearing shell with an oil hole must always be installed in the main bearing cap. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Neither A nor B
Excessive clearance at the crankshaft main bearings could result in which of the following conditions?a. High oil pressureb. Low oil pressurec. Aerated oild. Fluctuating oil pressures
Low oil pressure
Technician A states that the type of vibration damper most commonly used on truck diesel engines is the viscous type. Technician B states that the inertia ring drive medium on a viscous-type vibration damper is a rubber compound. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Technician A only
What do we call the location on a cam profile that is exactly opposite the toe?
Heel
On a cam profile described as mostly inner base circle, the profiles between IBC and OBC are known as what?
Ramps
Which of the following dimensions would be consistent with a typical engine timing gear backlash setting?a. 0.002” (0.05mm)b. 0.024” (0.60 mm)c. 0.008” (0.20 mm)d. 0.014” (0.36 mm)
0.008” (0.20 mm)
In which direction must a camshaft be rotated on a diesel engine with a crankshaft that is rotated clockwise?a. Clockwiseb. Counterclockwisec. Either clockwise or counterclockwise depending on the engine
Either clockwise or Counterclockwise depending on the engine
Which tool would be required to measure the cam lift of a cylinder block-mounted camshaft in position?
A dial indicator
A camshaft gear is usually precisely positioned on the camshaft using what?
Key and Keyway
When grinding a valve face to remove pitting, the critical specification to monitor during machining would be what?
Margin
Which of the following operating conditions would be more likely to cause a valve float condition?a. Operating in the droop curveb. Engine overspeedc. Engine lug downd. Operating in the torque rise profile
Engine overspeed
When grinding a new set of cylinder valve seats, which of the following should be performed before the machining?a. Install the valve guidesb. Adjust the valve yokesc. Install the rockersd. Install the valves
Install the valve guides
What is the reason for using a pair of oppositely wound valve springs?
To minimize valve dynamic flutter
Technician A states that the backlash in timing gearsets can be measured with a dial indicator. Technician B states that if the gear backlash is insufficient, the result can be gear whine. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Both A and B
Technician A states that helical cut gears are often used in engine timing geartrains because they operate more quietly. Technician B states that shaft thrust loads are much higher when helical cut gears are used. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Both A and B
Technician A states that when installing an interference-fit gear to a shaft, the gear should not be heated above 4008F. Technician B states that if an oxyacetylene rosebud is not available, an interference-fit gear should be pressed to the shaft using a hydraulic press. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Technician A only
Technician A states that it is good practice to lubricate the inside bores of camshaft bushings to facilitate camshaft installation. Technician B states that if the cam bushing oil holes are not properly aligned, an immediate camshaft failure could be the result. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Both A and B
Which of the following methods is used to transfer drive from the crankshaft to the camshaft on most commercial diesel engines?a. Fluid couplingb. Belt and pulleyc. Timing chain and sprocketd. Gears
Gears
Technician A states that variable valve timing (VVT) is used on some diesel engines to delay the closing of intake valves on the compression stroke. Technician B states that VVT is used to open the intake valves early during the power stroke. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Technician A Only
What type of cam geometry is required if the objective is to load the train that rides it for most of the cycle?a. Mostly IBC profileb. Mostly OBC profilec. Symmetrical OBC and IBC profiles
Mostly OBC profile
Technician A states that camshaft on a two-stroke cycle engine turns through one complete rotation per complete engine revolution. Technician B states that the camshaft on a four-stroke cycle diesel engine rotates through one revolution per two engine revolutions. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Both A and B
Technician A states that to check cam lift, the camshaft must be removed from the engine to obtain a valid reading. Technician B states that to check for a bent camshaft, the camshaft should be removed from the engine and runout tested in V-blocks. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Technician B Only
Technician A states that valves machined with 45-degree seats breathe with higher efficiencies than those machined with 30-degree seats. Technician B states that valves machined with 30-degree seats run cooler than those machined with 45-degree seats. Who is correct?a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B
Neither A nor B
