Engines Flashcards
The amount of air an engine is able to take into the cylinder compared with the volume of the cylinder is called?
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 SI metric system measures pressure in?
Pascals
When you are determining engine rotation using the SAE standard, the engine is viewed from?
The main power end of the engine
Which type of head design has the valves in the block?
“L” head engine
The main reason for using chrome cylinder liners is for?
Reducing the rate of wear on the cylinders
To check for out of round in a cylinder you must measure?
In the ring travel area, 90 degrees and parallel to the crank
Which liners are not exposed to engine coolant?
Dry liners
What is the most accurate method of checking bearing clearances?
Measure the shaft and bearings
Piston rings fall into 2 major groups?
- compression
- oil control
Maximum torque will occur on an engine at what point?
At the best volumetric efficiency
Deglazing of a cylinder with flexible hone promotes?
Good cylinder to ring lubrication.
The crankshaft on most modern diesels are made from?
Forged alloy steel
The main cause of crankshaft deflection on large engine installations is?
Foundation that is crooked or uneven
The usable power that an engine actually delivers is, refers to as?
Brake horse power
The main reason for counter weights on the crankshaft is?
Counter weights, balances reciprocating forces.
Valve clearance on a four stroke engine is normally adjusted with the piston at?
Top dead centre (TDC) compression stroke
Which engine part has the function of storing energy during the power pulses and then using that energy to carry the engine to the next power pulse?
Flywheel
An engine that has a larger stroke length then bore diameter is?
Under square
Running an engine without a thermostat would most likely cause?
Sludge
Abnormally high crankcase pressure could be caused by?
Scored cylinder
One sign that could be used to indicate a faulty spark plug in a running gas engine?
A cool exhaust manifold elbow
Excessive side clearance between the piston ring and the ring groove will cause?
Ring breakage and excessive oil consumption
The amount of contact on a dry liner is important for?
Correct heat transfer
Excessive valve lash could cause?
Insufficient scavenging
What can cause increased compression?
A build up of carbon in the combustion chamber
The in-line cylinder configuration has the advantage of?
A greater number of bearings to share the load
The quickest way to check the main bearing clearance is by?
Lift check
The mass of a stationary engine foundation should be how big?
2.5 times the mass of the complete engine
Which sensor would have the purpose of telling the computer the fuel is too rich or too lean?
Oxygen sensor
Excessive crankshaft deflection would cause?
Crankshaft fatigue
What fills the cylinder with air on a naturally aspirated engine?
Atmospheric pressure
When replacing piston oil rings ensure?
The rounded edge faces the top of the cylinder
What is always found in the cylinder head of an “I” head four stroke engine?
Valves, intake and exhaust passages
What is the purpose of the natural gas carburetor?
Proper air fuel (A/F) ratio
Which engine system uses the heat of a compressed gas for ignition?
Diesel engine
Abnormal oil consumption could be caused by?
Excessive valve guide clearance
How is an intake valve cooled in a typical industrial engine?
Intake air plus valve seat and valve guide contact
The piston compression ring which is least likely to stick is?
Keystone
The coolant in a pressurized system will have a boiling point ________ degrees higher for every ______psi
3 degrees F higher for every 1 psi
Which pistons will be fit looser in the cylinder than cast iron pistons and why?
Pure aluminum pistons because of the amount of expansion when heated
On a liquid cooled inline 4-stroke 8 cylinder Diesel engine the power pulse is located _________ degrees apart.
90 degrees.
In a 4-stroke engine the sequence of events would be?
Intake, compression, power, exhaust
If an engine has valve overlap of 30° this means that?
The intake valve opens 30° before the exhaust valve closes
Adding an intercooler to a turbocharged engine will?
Give a further power increase
A Waste gate (dump valve) is located?
Between the exhaust and the turbine
Which fuel is more susceptible to pre-ignition?
Gasoline
With normal combustion on an SI engine, ignition normally occurs?
When the spark is delivered, before TDC
If the exhaust valve is open while the intake valve is also open before and after TDC what happens?
Exhaust gas is being scavenged
On a diesel engine the governor controls the?
Fuel rack
Cylinder liner cavitation can be caused by?
Vibration
Engine knock (detonation) occurs when?
Two flame fronts colliding cause a rapid combustion of the fuel
Most cylinder wear occurs at the?
Top of ring travel
Spectra analysis program of engine oil will tell you?
The condition of the oil and engine wear
When starting a natural gas engine which has to be shut down for a few days, it should be barred over, doing this will?
Check for hydrostatic lock
Multi engine installations that have all the exhaust united into one manifold and muffler system can cause?
Condensation in the cylinder on the non-running engine
Work is expressed as?
As force unit times distance
How is heat removed from the piston in a diesel engine?
Oil spray and ring contact with cylinder walls
Setting the correct valve lash on a four stroke engine is best done?
After the intake valve closes
What is best used to set a natural gas A/F ratio?
Wideband oxygen sensor
What is the purpose of the converter on a LPG system?
Changes higher pressure liquid to lower pressure vapour
What is not required for a magneto type ignition system?
Battery
A sign that a diesel is running excessively cold is the emission of _________ smoke
White smoke
What does the stoichiometric mean as it relates to natural gas engines?
It is the chemically correct ratio to burn all of the oxygen and fuel
The primary circuit of a basic ignition circuit is?
The low-voltage part of the circuit
Pre-ignition occurs when, in the combustion process?
Before normal combustion
Lubrication for the cylinders of very large displacement engines can be accomplished with the use of?
Oil injection
What causes the air to flow through the carburetor on a natural gas engine?
Movement of the piston
What ratio does the camshaft turn in relation to the crankshaft in a four stroke engine?
1 to 2 (crankshaft in relation to camshaft would be 2 to 1)
High-octane fuel burns?
Slower (less volatile)
Too much fuel in carburetor is?
Rich
Too much air in carburetors is?
Lean
Valve over lap (4 stroke engine) takes place at the?
Start of the intake stroke
In a two stroke engine scavenging takes place?
After the power stroke
Valve face interference angle is sometimes used to apply?
Quick seating for initial start up after a valve job
What instrument is commonly used to check the crankcase ventilation system?
A manometer.
What does a pyrometer do?
It measures exhaust gas temperatures.
Best way to remove a ridge on a cylinder 6” or less is with?
Ridge reamer
Balanced manifold pressure is important?
To keep work being done by each cylinder constant.
