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310 T ENGINE SYSTEMS EXAM QUESTIONS AND CORRECT ANSWERS 100 %
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What is the ratio between exhaust temperatures to air intake temperature
a) 2: b) 4: c) 3: d) 1:1 - ANSWER c) 3:
JWACs are capable of reducing air intake temperatures by ____________.
a) 75°F b) 50°F c) 100°F d) 125°F - ANSWER c) 100°F
ATAAC system cooling is affected by which variable?
a) Surface area b) Road speed c) Ambient temperature d) All are correct - ANSWER d) All are correct
There should not be a pressure drop of more than _______, measured at ATAAC inlet and outlet.
a) 1 lb b) 10 lbs c) 5 lbs d) 3 lbs - ANSWER d) 3 lbs
When performing a restriction test of an ATAAC, the test needs to be performed at ____________.
a) rated HP b) idle c) full load d) high idle - ANSWER c) full load
After a catastrophic turbocharger failure, the ATAAC should be ____________.
a) flushed to remove debris b) restriction tested c) pressure tested d) All are correct - ANSWER d) All are correct
The temperatures and pressures exerted on ATAACs require the technician to use __________ to properly secure the pressure hoses.
a) gear clamps b) wire ties c) mechanic's wire d) spring operated clamps - ANSWER d) spring operated clamps
c) Internal restriction of a charge air cooler (CAC) d) CAC leaks - ANSWER c) Internal restriction of a charge air cooler (CAC)
Under what conditions does EGR gas pass through the CAC on a high-pressure cooled EGR system?
a) EGR gas never passes through the CAC b) When the EGR valve is open and the engine is under load c) Only at idle d) When the EGR bypass valve is opened - ANSWER a) EGR gas never passes through the CAC
Which of the following statements is true about CACs?
a) CACs enable the use of higher cylinder fueling rates. b) Any crack in the CAC is not acceptable and leads to low-power complaints. c) CACs reduce formation of particulates. d) Adding a CAC can significantly increase engine power output. - ANSWER a) CACs enable the use of higher cylinder fueling rates.
What is the last thing to do after servicing the cooling system of an engine with jacket water after cooling (JWAC)?
a) Pressurize the cooling system to check the JWAC for leaks. b) Adjust the coolant pH to prevent cooler corrosion. c) Road test the engine. d) Bleed the cooling system. - ANSWER a) Pressurize the cooling system to check the JWAC for leaks.
When using series turbocharging, the first stage of cooling or interstage cooling is:
a) always performed by a JWAC with a secondary cooling system. b) performed by an aluminum air-to-air aftercooler (ATAAC). c) performed by a JWAC. d) not necessary when using an ATAAC. - ANSWER c) performed by a JWAC.
What is the most likely cause of cracked ATAAC mounting brackets?
a) Thermal cycling (repeated heating and cooling) b) Loosened mounting bolts/hardware c) Mounting brackets that are too rigidly secured d) Vibration - ANSWER c) Mounting brackets that are too rigidly secured
Air inlet temperature of 100°F, may increase outlet exhaust temperatures by approximately ________.
a) 400°F b) 450°F c) 300°F d) 350°F - ANSWER c) 300°F
A diesel engine "snap test" should not be performed when ambient temperatures exceed __________.
a) 80°F b) 40°C c) 27°F
b) After the intercooler c) After the air filter d) In the exhaust stream - ANSWER c) After the air filter
Caterpillar's emission strategy system is known as ____________.
a) DGI b) VIVA c) They don't have one d) CGI - ANSWER d) CGI
Air intake filter performance testing on a turbo charged diesel engine is performed at ____________.
a) rated HP b) no load c) idle d) high idle - ANSWER d) high idle
What is the expected service life of a medium-duty air filter?
a) 1600 hours b) 1200 hours c) 2000 hours d) 900 hours - ANSWER a) 1600 hours
What is the flash point of Ethyl ether?
a) -65°F b) 160°F c) 320°F d) -49°F - ANSWER d) -49°F
What happens to the mass of intake airflow into an engine when the EGR is enabled?
a) The mass becomes cooler. b) The mass increases. c) Nothing happens. d) The mass decreases. - ANSWER d) The mass decreases.
Which of the following reasons best explains why air induction system noise is louder on a diesel-fueled engine than on a gasoline-fueled engine?
a) The use of a turbocharger b) Increased amount of valve overlap c) Smaller clearance volumes in cylinders d) Larger engine displacement - ANSWER b) Increased amount of valve overlap
What effect will high inlet air temperature combined with high humidity have on engine performance?
a) Lower power output compared with cooler, drier conditions b) Increased power compared with cooler, drier conditions c) Reduced engine emissions compared with cooler, drier conditions d) No difference in power output compared with cooler, drier conditions - ANSWER a)
b) Using ether while the engine is running, then listening for engine speed increase at leak points c) Lube oil analysis to check for silica d) Spraying intake piping and joints with soap and water when the engine is running - ANSWER c) Lube oil analysis to check for silica
Which air filter element will provide the highest filtration efficiency (i.e., which removes the most dirt)?
a) A dirty, dry paper-type filter b) An oil bath-type air filter c) An oil-wetted gauze-style air filter d) A new, dry paper-type filter - ANSWER a) A dirty, dry paper-type filter
Which of the following air intake systems will best pre-clean dirt and water from the air intake of an on-highway, diesel-powered vehicle?
a) Front-mounted air inlet b) Composite intake c) Ram air induction d) Side-mounted air inlet - ANSWER d) Side-mounted air inlet
Which of the following practices is recommended for the servicing of a restricted air filter?
a) Cleaning from the inside out with compressed air b) Dropping or lightly tapping the filter against the shop floor c) Verifying restriction with a trouble light d) Replacing the filter - ANSWER d) Replacing the filter
Which category of engine oil is compatible with biofuels?
a) ASE b) CJ- c) PC- d) API - ANSWER c) PC-
Which governing body is responsible for affixing the oil viscosity designed description of oil labelled such as "15W40"?
a) UTI b) API c) EPA d) SAE - ANSWER d) SAE
Motor oils are typically made up of __________ chemical additives.
a) 20-30% b) 25-45% c) 10-15% d) 15-25% - ANSWER d) 15-25%
Shortened oil change intervals can be expected when using a biofuel and fossil fuel mix above ____________.
a) 20% b) 30%
a) engines oil cooler b) secondary oil filter c) main oil gallery d) primary oil filter - ANSWER c) main oil gallery
The purpose of a centrifugal oil filter is to remove ____________.
a) soot b) water c) oxygen d) All are correct - ANSWER a) soot
Oil pressure regulating valves operate by ____________.
a) engine rpm b) oil temperature c) centrifugal force d) spring force - ANSWER d) spring force
Which series of engine oils are used in diesel engines?
a) C series b) ASTM c) S series d) SAE - ANSWER a) C series
Which of the following is the most recent diesel engine oil classification?
a) CJ b) SG c) SB d) CA - ANSWER a) CJ
When should engine oil be changed in a diesel?
a)It depends on the distance travelled b) It depends on the quality of the oil used c) It depends on the number of accumulated engine hours since the last service d) At 3-5% soot loading - ANSWER d) At 3-5% soot loading
The "15W" in 15W-40 engine oil stands for which of the following?
a) The thickness of the oil when hot b) Multiple viscosities c) Viscosity at 0°F (-18°C) d) Viscosity at 212°F (100°C) - ANSWER c) Viscosity at 0°F (-18°C)
Maximum lubrication oil temperature not exceed:
a) 250°F (121°C). b) 235°F (113°C). c) 215°F (102°C). d) 200°F (93°C). - ANSWER a) 250°F (121°C).
c) A defective pressure regulating valve d) A restricted oil gallery - ANSWER c) A defective pressure regulating valve
Which of the following is the most likely cause of excessively low oil pressure?
a) Hot engine oil b) Fuel in the oil c) Worn out rod and main bearings d) Engine oil leaks - ANSWER c) Worn out rod and main bearings
A measured limit to exhaust backpressure is ____________.
a) 10 inches/hg b) 14 inches/hg c) 14 inches/h2o d) 3 inches/h2o - ANSWER c) 14 inches/h2o
Which exhaust manifold design promotes sequential exhaust flow to the turbocharger?
a) series type b) inline type c) parallel type d) pulse type - ANSWER d) pulse type
A volvo epg is operated by ____________.
a) air pressure
b) coolant pressure c) oil pressure d) a stepper motor - ANSWER a) air pressure
Another common name that relates to a pyrometer is ____________.
a) variable thermistor b) thermocouple c) photo sensor d) thermo sensor - ANSWER b) thermocouple
Some exhaust brake designs incorporate a _________________ to maintain constant backpressure.
a) spring-loaded restrictor b) variable orifice c) nonclosing butterfly vane d) restricted orifice - ANSWER a) spring-loaded restrictor
Compression release brakes are commonly found in engines over __________.
a) 10 l b) 8.9 l c) 6.7 l d) 11 l - ANSWER d) 11 l
Energy used to compress the air is lost when the exhaust valve opens near __________.
d) 2,4,6 - ANSWER c) 1,3,
What is the main purpose of a divided or split type exhaust manifold?
a) ease of installation b) dissipation of exhaust heat c) prevent interference of exhaust pulse d) ease of manufacture - ANSWER c) prevent interference of exhaust pulse
To maintain control of a vehicle equipped with a compression release brake, what should happen when a wheel lock-up is sensed by the anti-lock braking system (ABS) module?
a) The compression release brake will remain enabled if the programmable parameter is set to Latch. b) The ABS will be deactivated by signals carried over the J-1939 network. c) The J-1939 network will carry signals to deactivate the engine brake. d) The J-1939 network will carry signals to activate the engine brake. - ANSWER d) The J-1939 network will carry signals to activate the engine brake.
Exhaust backpressure and the retarding force of an engine equipped with an exhaust brake is limited by which of the following?
a) Exhaust valve spring tension b) Exhaust temperature c) Engine displacement d) Engine speed - ANSWER a) Exhaust valve spring tension
Which of the following is most likely a cause of high engine exhaust temperature?
a) High engine oil consumption b) Excessive turbo speed c) Excessive boost pressure d) A restricted air filter - ANSWER d) A restricted air filter
Maximum normal exhaust temperature is typically which of the following?
a) 950°F (510°C) b) 1250°F (649°C) c) 2500°F (1371°C) d) 1600°F (871°C) - ANSWER a) 950°F (510°C)
Which of the following exhaust system requirements is typically needed for a diesel engine with 400 horsepower (298 kilowatts) or more?
a) 5½ (13 cm) exhaust pipe b) Vertical exhaust system c) Dual exhaust d) A resonator before the muffler - ANSWER c) Dual exhaust
During which of the following strokes does a compression release brake open the exhaust valve?
a) Exhaust b) Power c) Compression d) Intake - ANSWER c) Compression
