Week 3 Prime Movers Flashcards
Prime movers
True or false The engine flywheel should be pinned and locked out before entering the crankcase.
True
Before performing any maintenance on a recently run engine, you must do what?
disconnect any electrical feed and close, lock, tag and purge all gas sources.
True or false When working in areas of high concentrations of hydrogen sulphide (H2S), you should always wear a personal alarm monitor.
True
The thermal efficiency of an engine is best described as the ability of the engine to what
change the energy in the fuel to usable heat energy and power.
The amount of air an engine is able to take into the cylinder compared to with the volume of the cylinder is called what
Volumetric efficiency
The description of compression ratio is best stated as
the cylinder volume plus the combustion chamber volume, divided by the combustion chamber volume.
The description of compression ratio is best stated as
the cylinder volume plus the combustion chamber volume, divided by the combustion chamber volume.
True or false Two stroke engines have running mates
False, only four store have running mates. This is because the two-stroke engine fires on all cylinders every Revolution ( 360° of crankshaft rotation).
How do you find the engine displacement?
Area of bore by the length of stroke by number of cylinders.
True or false When comparing a diesel engine to a gas engine the compression pressures and ratios are three times high or more .
False, it twice as much.
When air is compressed, what are the noticeable effects?
The temperature increases, as the volume becomes smaller.
When you are determining engine rotation using the SAE standard, you view the engine from?
the main power end of the engine
Which type of head design has the valves in the block?
L head engine
True or false Indicated horsepower is the power at the flywheel of the engine.
False, indicated horsepower is the theoretical power of an engine.
True or false A two-stroke engine completes one cycle in 720 ° of rotation.
False, it is completed in 360°.
True or false Potential energy is the energy resulting from the motion of an object.
False, this is kinetic energy.
True or false An undersquare engine is an engine with a larger stroke than bore.
True
Blowby is leakage past the rings.
True
Running mates are pistons that reach TDC at the same time.
True
What are the three requirements to make fuel combust?
Fuel, air, and ignition.
True or false The fuel must be atomized and mixed with air to be burned.
True
True or false At the end of the exhaust stroke, the intake and exhaust valves are open at the same time.
True
A two-stroke engine makes twice as much power as a four-stroke engine of the same capacity.
False, it is the opposite. This is because the effective power stroke is shorter.
True or false Integral engines require proper alignment with the driven equipment.
False, because they use the same crankshaft and block.
Spark-ignition engines have a much lower compression ratio than diesel engines.
True
The classification for an engine with a normal operating speed of 800 rpm is a low-speed engine.
False, An engine with a normal operating speed of 800 rpm would be classified as a medium-speed engine.
What is the function of the flywheel?
The flywheel stores energy and smoothes the power pulses from the pistons.
True or false The lighter the flywheel, the smoother the engine runs.
False, the heavier the smoother.
The linear and rotary motion are create how in the ICE?
Linear from the piston and rotary from the crankshaft. Connected by the connecting rod.
What is the purpose of the balancer?
To reduce crankshaft torsional vibration.
You should check the machined surfaces of the cylinder block for flatness using what two measuring tools?
straight edge and feeler gauge
What could misaligned main bearing bores cause?
excessive bearing wear or a broken crankshaft.
True or false An underslung crank has the main bearing caps at the bottom of the crank.
True
Which of the following should you not use to clean aluminum components?
A hot caustic soap tank
Identify two measuring tools that you use in order to check the main bearing bores on an engine block.
Inside mics and dial bore gauges.
True or false You can repair cylinder liners on large engines by hard chroming and grinding to size.
True
Why do you use alloy cast iron for engine block material?
The alloy cast iron is strong.
Why must the outside diameter of a dry liner fit the cylinder block bore correctly?
to allow heat transfer from the liner to the block material and to support the liner
True or false Wet type cylinder liners are in direct contact with the coolant.
True
What do leaking o-rings on a wet liner cause?
coolant to enter the crankcase.
When reconditioning a cylinder bore, you can use a de-glazing hone to do what?
Restore cylinder wall crosshatch
Identify four important checks that you must complete during a new cylinder liner installation.
Check cylinder bore for out-of-round, taper and cracks, Check all seal surfaces, Check liner counter bore, and Check liner protrusion height.
which is the most common fuel injection system?
The mechanical injection system is the most used.
true or false most gasoline engines do not use cylinder liners.
true
true or false gasoline engines have heavier pistons than diesel.
false, diesel have heavier pistons to help dissipate heat due to higher temperatures.
true or false on a Two-stroke diesel scavenging engine with exhaust ports the scavenging valve is open as the piston lowers from TDC?
false, this would remove all the higher pressure air that the piston builds.
true or false in a two stroke engine the camshaft travels at one half the speed of the crankshaft.
False, two stroke do not have camshafts. camshafts are found on four stroke to regulate intake and exhaust valves.
True or false An underslung crank has the main bearing caps at the bottom of the crank.
True
Four stroke six cylinder engines should have 60 ° between power strokes. A) true b) false 4.
False, they should have 120° degrees between power strokes.
Crankshafts should be stored by standing them on end, or on a level floor on V blocks for larger crankshafts.
True
What is the purpose of the crankshaft?
Change reciprocating motion into rotary motion.
Crankshaft journal fillets must be maintained to?
Prevent crankshaft breakage
What is mounted onto the flywheel to aid in starting purposes?
A ring gear
A harmonic balancer that has an interference fit should be removed using
A puller
Another name for friction bearings used in engines is:
Precision inserts
Focalized (spot) wear on a bearing is likely caused by:
Foreign material between the bearing shell and bearing bore.
When installing bearings, you should not lubricate:
The bearing backs
When removing main and / or connecting rod bearings, you should mark them for:
Reinstallation and future analysis.
What is plastigage?
Pliable plastic string
List the four main components of a piston and connecting rod assembly.
Connecting rod, piston, piston pin, and piston rings.
What is the purpose of a connecting rod?
It forms a link between the piston and the crankshaft that transmit the force of combustion.
True or false The connecting rod bearing clearance can be checked by the lift check method.
True
True or false Aluminum pistons are fitted tighter than cast iron pistons.
False, expands more
True or false Drilled holes in the piston’s oil ring groove drains oil back to the crankcase.
True
True or false Rings are installed with the dot, notch or number toward the crankshaft.
False, does Face the pressure
True or false Ring gaps should be lined up one above the other prior to piston installation.
False, they must be staggered to prevent leakage.
true or false Oil control rings depend only on their expanders to maintain contact with the cylinder walls.
True