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Power Units Test 2
Terms in this set (100)
______________ is the point at which the piston is closest to the cylinder head.
TDC (top dead center)
On a four stroke cycle engine, 2 revolutions of the crankshaft correspond to _________ revolution(s) of the camshaft.
The foam air cleaner element should be cleaned with ___________.
Soapy water solution
The minimum grade of gasoline recommended for small four stroke cycle engines is:
A(n) ________________________ is an thin cast strip designed to provide efficient air circulation and dissipation of heat away from the engine cylinder block into the air stream.
What feature is NOT likely find on a two-stroke cycle engine?
Engine oil filler plug
What is a type of governor used on a small engine?
If a small engine is determined to be about 33 percent efficient in its use of heat produced through combustion to power the engine, where does the other 67 percent of the heat produced go?
What should be used to measure the crankshaft journal wear?
In the cylinder block, what holds the valve stem in alignment?
After a four-stroke cycle engine has completed one full operating cycle, how many degrees has the crankshaft rotated?
What oil has the highest viscosity?
Cylinder wear is greatest at:
the top of the ring travel
The purpose of tightening head bolts in the proper sequence, and to a specific torque is to ____________________.
Compression in an engine is referred to as a ratio. For a gasoline engine a compression ratio of ____:____ would be expected.
As compression happens in an engine the air and fuel mixture will:
On the compression stroke of an engine the gasoline changes from a ____________ to a _____________.
In a ____________ type of engine, air is drawn into the cylinder by a natural air pressure differential.
What would be one of the possible impacts of inadequate compression?
Unburned fuel released into the exhaust
Undesirable and unaccounted for all that.........called _________?
Detonation is often heard as a _____________ in the engine.
Pre-ignition occurs when the piston is moving up in the direction of what stroke?
One piece valve designs are often used for what type of load?
Valve seats and valve faces are ground on slightly different angles. What is this angle called?
Valves move in a machined surface. What is this surface called?
Pistons provide a way to convert ___________________ energy into _______________ energy.
Pistons have grooves in them that hold piston rings. What is the top and bottom of each groove called?
What is the most common fuel in small engines?
Each type of fuel has a specific point where most efficient combustion occurs. What is the ratio called?
When adjusting the air to fuel mixture to get the most power we would want to have a slightly __________ air to fuel ratio.
Octane rating provides an indication of the ability of fuel to resist what action?
What component puts gasoline into the air stream as it enters an engine?
Crankshafts are most often oriented in ___________ or _____________ directions?
A Venturi in a carburetor causes the air to speed to _________________ and the air pressure to __________________.
What are the three basic elements needed to make an engine run?
air, fuel, ignition
In a single cylinder engine with 2 valves per cylinder, how many cam lobes would you expect to find on the camshaft?
A connecting rod establishes a connection between the _________________ and the _______________.
Valves are typically opened by the _____________?
A crankshaft is spinning at 1200 RPM. How fast is the camshaft spinning?
What additives were used in early gasoline to increase the octane rating?
Air moves through the carburetor fuel is pushed into the air stream through the ______________________.
A governor attempts to maintain a constant engine ______________________.
As a valve wears the valve margin will ___________________.
As cylinder bore is worn the diameter will ____________________.
SHORT ANSWER: What are the four events (strokes) that must occur in an engine? (list in order) Give a brief description of each cycle.
(suck) Intake - takes it in
(squeeze) Compression - starts to compress
(bang) Power - the work being done
(blow) Exhaust - releases material
SHORT ANSWER: Give a brief description of the function of compression rings and oil control rings.
Compression rings keep compression where it is needed to be. Oil control rings scrape all of the oil off of the cylinder wall.
SHORT ANSWER: What is the function of a flywheel on an engine?
spins around/rotates on crankshaft which turns parts
SHORT ANSWER: Explain why a 2 stroke engine most likely does not have an oil control ring.
it will build up so there is no need for it
SHORT ANSWER: What is the function of a valve spring?
The opening and the closing that allows the oil to go in and out
SHORT ANSWER: Explain the difference in pneumatic and mechanical governor systems.
Mechanical - is actually mechanically done
Pneumatic - automatically done
SHORT ANSWER: Fuel is stored in a tank and then moves into the bowl of the carburetor. Explain how the carburetor regulates the amount of fuel in the bowl.
Has an automatic valve called needle and seat valve. Has a float.
SHORT ANSWER: Explain why a cam shaft must rotate at exactly one half of the crankshaft speed.
It is because the gear is bigger. The crank gear has to spin 2 times as fast to be able to keep up.
SHORT ANSWER (chart question): What is the amount of taper in this cylinder at the following locations?
12:00 _______________ ----- 3:00____________________
SHORT ANSWER (chart question): What is the out of round of this cylinder in the following locations?
Top___________________ ----- Bottom_________________
SHORT ANSWER: Is this cylinder usable based on the measurements and the given reject sizes?
The _________________ _________ of an engine is a comparison of the volume of the combustion chamber with the piston at BDC to the volume of the combustion chamber with the piston at TDC.
During the intake stroke the intake valve is __________ and the exhaust valve is _________
open and closed
Connects the piston to the crank
The ______________ is an engine component that converts the linear motion of the piston into rotary motion
The _______ of an engine is the linear distance that a piston travels in the cylinder bore from top dead center to bottom dead center.
Verify distance between parts
Measures change in position of parts
Measure thickness and diameter
Measures inside, outside, and depth of parts
____________ is the process of reducing or squeezing a charge from a large volume to a smaller volume in the combustion chamber
The camshaft will always operate at _______ the speed of the crankshaft.
Main structure of an engine which supports and helps maintain alignment of internal and external components
The cast aluminum alloy or cast iron engine component fastened to the end of the cylinder block farthest from the crankshaft.
Converts the linear (reciprocating) motion of the piston into rotary motion
Cylindrical engine component that slides back and forth in the cylinder bore by forces produced during the combustion process
What is used to measure the crankshaft journal wear?
A two-stroke cycle engine is an engine that uses two strokes to complete ____ operating cycle(s) of the engine.
A ____________ ______ is an engine component that transfers motion from the piston to the crankshaft and functions as a lever arm.
In the cylinder block, what holds the the valve stem in alignment?
Compresses valve springs for installation or removal
Valve Spring Compressor
A ______ ____________ compresses piston rings for installation.
Which feature described below would you likely NOT find on a two-stroke cycle engine?
Engine oil filler plug
Which of the following is a type of governor used on a small engine?
Which of the following oils has the highest viscosity?
Which of the following additives were used in early gasoline this to increase the octane rating?
BONUS: I have a V-8 engine with a bore of 4,000 inches and a stroke of 3.48". How many cubic inches of displacement does this engine have?
What are the 3 elements of a fire?
What does BDC stand for?
Bottom dead center
Define Bottom Dead Center
The furthest extent of the piston's downward (toward the crankshaft) travel
Four strokes that occur in an engine?
Give a description of the four strokes in an engine
Intake- During the intake stroke, the piston moves downward, drawing a fresh charge of vaporized fuel/air mixture.
Compression- As the piston rises, the poppet valve is forced shut by the increased cylinder pressure. Flywheel momentum drives the piston upward, compressing the fuel/air mixture.
Power-At the top of the compression stroke, the spark plug fires, igniting the compressed fuel. As the fuel burns it expands, driving the piston downward.
Exhaust-At the bottom of the power stroke, the exhaust valve is opened by the cam/lifter mechanism. The upward stroke of the piston drives the exhausted fuel out of the cylinder
What is the function of a cooling fin?
The extended element of a heat-transfer device that effectively increases the surface area.
What do four stroke engines mix with gasoline?
What do two stoke engines mix with gasoline?
What are two types of air cleaners that can be used in small engines?
What does the crankshaft do? ( In terms of motion)
It is the system that converts linear energy into rotational energy
What is viscosity?
oil's resistance to flow and shear
What purpose does the engine block serve?
It contains the crankcase and all its parts, including gaskets, valves and seals. The engine block contains cylindrically bored holes for the pistons and ways to attach other components such as the cylinder head.
Dial Calipers are measured to the nearest __________ of an inch.
What is the function of a flywheel?
It is a cooling system. The shroud is shaped to direct airflow from the flywheel fan across the engine's hot spots, notably the cylinder and head. These parts have fins that aid the cooling effect by increasing the surface area available to the air.
What does a gas engine produce that is toxic?
Where is the cylinder wear greatest?
What direction is the piston moving on the intake stroke?
From TDC to BDC
What is the difference between a nut driver and a screw driver?
A nut driver is a shaft and a socket. Similar to the screwdriver but used for tightening nuts and bolts
What's the difference between a ratchet and a nut driver?
A ratchet is used to tighten or loosen a bolt using a socket attachment that is interchangeable. It is a ratcheting socket wrench.
THIS SET IS OFTEN IN FOLDERS WITH...
Power Units Test 1
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