BRAE 335 Internal Combustion Engines Winter 2021
Horsepower lost because of friction in the engine is called ____ horsepower:
Frictional
Theoretical horsepower is referred to as:
Indicated Horsepower
The oil scraped off the cylinder walls by the oil control rings is:
Sent back to the crankcase through small holes in the ring groove
Two cylinders drawing air and fuel from the same port are called
Siamese Ports
Two cylinders cast together in an embolic block are called:
Siamese Sleeves
Technician A says that counterweights are placed on the crankshaft to improve balance. Technician B says that thrust surfaces on the crankshaft absorb radial (up and down) movement of the crankshaft. Who is correct?
Technician A
Technician A says that crankshafts may be manufactured by either forging or casting. Technician B says that those manufactured by casting are stronger than those manufactured by forging. Who is correct?
Technician A
Technician A says that counterweights are placed on the crankshaft to improve balance. Technician B says that thrust surfaces on the crankshaft absorb radial (up and down) movement of the crankshaft. Who is correct?
Technician B
_____ are used to absorb the axial thrust produced on the crankshaft:
Thrust Bearings
Pistons are designed to have a major and minor:
Thrust Surface
A/An ____ is used to reduce the heat flow to the top piston ring:
Heat Dam
Which type of combustion chamber is designed as a half circle:
Hemispherical combustion chamber
Which of the following valve parts are worn when oil leaks into the exhaust stream:
Valve Guides
Which device is used to reduce torsional vibration?
Vibration Damper
What is the CID displace of an eight cylinder engine that has a bore of 4.00 inches and a stroke of 3.48 inches and ahead volume of 6.3 cubic inches?
349.67 CID
How many power pulses are there on a 8 cylinder engine when the crankshaft turns 1 revolution:
4
What is the compression ratio of the engine in question 92?
7.48 to 1
Technician A says that to calculate engine displacement use the formula: .875 x bore squared x head volume x the number of cylinders. Technician B says that engine displacement is calculated when the piston is at top dead center or TDC. Who is correct?
A only
Technician A says that an automobile engine converts chemical energy to thermal energy. Technician B says that an automobile engine converts thermal energy to mechanical energy. Who is correct?
B Only
Technician A says the order of strokes on a four-stroke engine is intake, power, compression, and exhaust. Technician B says the order of strokes on a four-stroke engine is intake, compression, power, and exhaust. Who is correct?
B Only
Technician A says that as frictional horsepower increases, fuel consumption decreases. Technician B says as frictional horsepower increases, engine efficiency decreases. Who is correct?
B only
As the gap end of the compression ring increases:
Blow-by increases
Technician A says that a 4-valve engine is designed to improve the volumetric efficiency. Technician B says that a 4-valve engine is designed to produce more horsepower. Who is correct?
Both A & B
Technician A says that bearing clearance is provided so that enough oil is allowed to flow between the crankshaft and the bearing to prevent metal-to-metal contact. Technician B says that excessive oil clearance can cause oil pressure to be reduced. Who is correct?
Both A and B
Technician A says that if the valve guides are worn out of specifications, oil may leak into the exhaust, Technician B says that if the exhaust valves are burned, compression gases will leak into the exhaust. Who is correct?
Both A and B
Technician A says that poor crankshaft to block alignment may cause crankshaft wear. Technician B says that line boring the engine block produces the proper crankshaft to engine block alignment. Who is correct?
Both A and B
Technician A says that some engines use variable valve timing systems. Technician B says that when using a variable valve timing system, the computer can change valve timing while the engine is running. Who is correct?
Both A and B
Technician A says that the four-stroke engine uses intake and exhaust valves to control the pressure in the combustion chamber. Technician B says the four-stroke engine uses a intake valve to control the vacuum in the cylinder. Who is correct?
Both A and B
Technician A says that the piston is connected to the crankshaft by the connecting rod. Technician B says that the crankshaft continues turning between combustion pulses because of the flywheel. Who is correct?
Both A and B
Technician A says that the top of the cylinder head should be checked for roughness. Technician B says that the top of the cylinder head should be checked for flatness. Who is correct?
Both A and B
Technician A says that today's engines now have variable valve timing. Technician B says that mechanical and hydraulic mechanisms are used to control variable valve timing. Who is correct?
Both A and B
Technician A says that variable valve timing means that the engine has a broader power band. Technician B says that variable valve timing has the timing and cam lobes of a racing engine and a standard engine. Who is correct?
Both A and B
Technician A says the gas engine used in a car is called an external combustion engine. Technician B says that a gas engine used in most cars is called a reciprocating engine. Who is correct?
Both A and B
How is a load applied to a vehicle to measure road horsepower?
By a chassis dynamometer
Which of the following lifters will produce the least wear on the camshaft?
Cam Followers
When the volume above the piston at BDC is divided by the air volume above the piston at TDC, the result is called:
Compression Ratio
_____ are used to seal up holes (used to remove sand after casting) in the block and can protect the block at times from cracking if the coolant freezes:
Core Plugs
The object that is the foundation of the engine and the point to which all other parts are attached is called the:
Cylinder Block
A gasoline engine converts chemical energy directly into mechanical energy.
False
Compression ratios of 12 to 1 are common on automotive engines.
False
Dial calipers are used to measure the taper in a cylinder.
False
Embolic engine blocks have separate cylinder liners cast in the block.
False
Four stroke-cycle engines have a power stroke for every one rotation of the crankshaft.
False
Hydraulic lifters absorb the valve train clearance by using combustion pressure inside the lifter
False
Replaceable liners are common in most cars produced today.
False
The compression stroke occurs when the exhaust gases are leaving the cylinder.
False
The diameter of the cylinder is called the sleeve.
False
Theoretical horsepower is a useful indicator when purchasing an engine.
False
Thrust bearings are used on the crankshaft to absorb radial loads.
False
When the valve is ground at a different angle than the seat by 1 degree, a/an ____ is obtained:
Interference Angle
The small lug on the bearing insert is used to:
Keep the bearing from spinning in the bore
The greater the frictional horsepower, the:
Lower the gasoline mileage
The distance between the valve face and the valve head is called the:
Margin
The greatest amount of cylinder wear is found:
Near the top of the cylinder bore
Technician A says that the exhaust stroke occurs immediately before the power stroke. Technician B says that the intake stroke occurs immediately before the exhaust stroke. Who is correct?
Neither A or B
Technician A says the type of engine most commonly used in vehicles is the radial type. Technician B says the type of engine most commonly in vehicles is the opposed type. Who is correct?
Neither A or B
As the amount of main bearing clearance increases, which of the following happens:
Oil Pressure decreases
The part in the engine that moves up and down in a cylinder is called the:
Piston
Technician A says that needle bearings are placed between the connecting rod/cap assembly and the crankshaft. Technician B says that insert bearings are placed between the engine block/cap assembly and the crankshaft. Who is correct?
Technician B
Technician A says that the connecting rods are attached to the crankshaft main journal. Technician B says that the main journal is the part of the crankshaft that is placed in the engine block. Who is correct?
Technician B
A precision straight edge and a feeler gage can be used to check the flatness of an engine head or block.
True
Because of the heat of expansion, there must be a valve train clearance that can be either manually or automatically accounted for.
True
Diesel engines are built heavier because they have higher compression than gasoline engines.
True
During normal operation the cylinder wears in the shape of a taper and also egg-shaped.
True
In a four stroke-cycle engine the crankshaft turns two revolutions during a complete cycle.
True
In most internal combustion engines the combustion starts and stops.
True
In most internal combustion engines the stroke of the engine is the distance the piston travels from TDC to BDC.
True
Micrometers can measure lengths in 0.001 of an inch.
True
Milling the head or block can greatly change the CR.
True
Pistons are cam ground so they will fit into the cylinder properly after heat expansion.
True
Some four stroke-cycle engines must have three valves per cylinder in order to function properly.
True
The CID of and engine can also be expressed in CC or L.
True
The camshaft and crankshaft are to be timed to each other by different mechanisms.
True
The camshaft on a four stroke-cycle engine turns at half the speed of the crankshaft.
True
The crankshaft on an automotive engine of today has holes drilled from each main bearing journal to the connecting rod journal for lubrication.
True
The power stroke occurs when the air-fuel mixture is ignited.
True
The shape of the camshaft lobe determines how quickly the valves open and close.
True
Volumetric efficiency is a measurement of how well air flows through an engine.
True
When the torque and engine rpm are known, the horsepower can be calculated.
True
Thrust surfaces are machined on the crankshaft to:
absorb axial thrust
Acids ____ in an engine's lubricating system:
can be produced
The device used to change reciprocating motion to rotary motion on the engine is called the:
crankshaft
An engine lubricating system is designed to: a. Cool the engine b. Clean and seal the engine c. Lubricate the engine d. all of the above
d. all of the above
Main bearings are designed for: a. Fatigue resistance b. Embeddability c. Conformability d. all of the above
d. all of the above
Other methods are used to classify engines. Which of the following method(s) is used to classify engines: a. By the Cycles b. by the Ignition System c. by the Fuel system d. all of the above
d. all of the above
Valve mechanisms can wear on: a. The valve stem. b. The valve face and seat. c. The valve guide. d. all of the above
d. all of the above
Which of the following are used to reduce harmonics in valve springs: a. Variable spring pitch b. More than one spring c. Small spring vibration damper d. all of the above
d. all of the above
Which of the following is a type of sleeve or liner used on a cylinder block: a. Wet sleeve b. Dry sleeve c. Cast in liner d. all of the above
d. all of the above
Which of the following is true about horsepower and torque: a. Torque is a measure of rotation and load; horsepower is measured in a straight line. b. Horsepower is measured over a period of time c. Torque is measured in foot-pounds d. All of the above
d. all of the above
The slant engine is used because the engine:
has a lower profile
Rocker arm ratio is used on valve mechanisms to:
open the valve a certain distance
When 550 pounds are lifted in 1 ___ a distance of 1 foot, 1 horsepower is created:
second
The reason for having a 4-valve engine is:
so more air and fuel can enter the engine
