Motor Flashcards
The highest pressure in a diesel engine cylinder normally occurs __________.
after TDC
In a diesel engine, after ignition of the fuel occurs, but before the piston reaches TDC, there is little change in the cylinder __________.
volume
Which statement about diesel engine combustion is true?
Maximum cylinder firing pressure is not developed until the piston passes TDC.
The duration of the power event shown in the four cycle engine polar timing diagram is represented by how many crankshaft degrees of revolution? MO-0084
125 degrees
In the illustrated polar timing diagram for a four-stroke cycle diesel engine, relative to crank degrees of travel with respect TDC or BDC as appropriate, when does the intake valve open? MO-0084
75 degrees before TDC
In the illustrated polar timing diagram for a four-stroke diesel engine, relative to the number of crank degrees before or after TDC or BDC as appropriate, when does the intake valve close? MO-0084
45 degrees after BDC
According to the illustrated polar timing diagram for a four- stroke cycle diesel engine, the exhaust valve is open for a duration of how many degrees of crank travel? MO-0084
320 degrees
According to the illustrated polar timing diagram for a four- stroke cycle high speed diesel engine, the period of valve overlap occurs for a duration of how many degrees of crank travel? MO-0084
160 degrees
The polar timing diagram shown in the illustration is of a four stroke cycle, high speed diesel engine, with fuel injection timing commencing at 10° BTDC. Approximately how many degrees will the crankshaft rotate from the point at which fuel injection begins to the point where the exhaust valves begin to open? MO-0084
135°
Which segment of the two cycle engine diagram shown represents compression? MO-0037
I
Which segment of the two cycle engine diagram shown in the illustration represents ‘supercharging’? MO-0037
III
Which segment of the two cycle engine diagram shown in the illustration represents the exhaust event? MO-0037
IV
Which segment of the two cycle engine diagram shown represents the power stroke? MO-0037
VI
If point #1 in the diagram shown is the beginning of gas compression, which of the cycles listed is being illustrated? Illustration MO-0036
Diesel
In the theoretical diesel cycle, shown in the illustration, which of the listed conditions normally takes place between points “3” and “4”? MO-0036
Expansion
In the pressure-volume diagram shown in the illustration, curve ‘A-d’ indicates __________. MO-0035
combustion at approximately constant pressure
In the pressure-volume diagram, shown in the illustration, the volume line is divided into 16 units indicating __________. MO-0035
a 16 to 1 compression ratio
In the pressure-volume diagram, shown in the illustration, the volume line is divided into 16 units indicating __________. MO-0035
a 16 to 1 compression ratio
In the pressure-volume diagram, shown in the illustration, what is indicated to have occurred by the line connecting points “d” and “e”? MO-0035
The combustion gases have expanded.
In the pressure-volume diagram, shown in the illustration, what occurs between points “e” and “f”? MO-0035
Pressure in the cylinder decreases.
In the pressure-volume diagram, shown in the illustration, what occurs between points “e” and “f”? MO-0035
Exhaust blow down occurs.
In the pressure-volume diagram shown in the illustration, the atmospheric pressure line is indicated by line __________. MO-0035
C
In the pressure-volume diagram shown in the illustration, fuel injection occurs at point __________. MO-0035
C
Which of the bearings listed below is most widely used for the main and connecting rod bearings of a modern high-speed diesel engine?
Precision insert
Babbitt is a metal alloy commonly used for lining __________.
Precision bearings
Which of the following methods is used to securely fasten the Babbitt lining of a reduction gear bearing to its shell?
The Babbitt is centrifugally spun into the bearings or cast under a pressure head.
Which of the following types of bearings are used as line shaft bearings?
Ring-oiled, Babbitt-faced, spherical seat, shell
From the data given in the illustration, which pair of pistons listed are mounted on the same crank throw? MO-0004
3L/3R
From the engine data given in the illustration, what is the swept volume of any one engine cylinder? MO-0004
4766 cubic inches
From the engine data shown in the illustration, what would be the average piston speed if the engine were turning 400 RPM? MO-0004
1400 ft/min
From the engine data given, after cylinder #1L fires, how many degrees of crankshaft rotation must take place before #4L cylinder fires? MO-0004
90°
From the engine data given in the illustration, what is the full load air manifold pressure? MO-0004
15.22 psi
The camshafts on the engine, shown in the illustration, operate at a speed equal to __________. MO-0005
one-half of the crankshaft speed
Which of the following characteristics can be determined about the standby diesel engine shown in the illustration? MO-0005
The camshaft rotates at one half the engine speed.
According to the diagram shown in the illustration, the lube oil system can best be described as a __________. MO-0007
wet sump system
If the manufacturer’s instructions do not state otherwise, which of the following progressions represent the best order for tightening the head bolts shown in the illustration? MO-0028
15372648
Which of the indicator diagrams illustrated depicts the condition that should be corrected by retarding only the timing? MO-0029
A
The instrument shown in the illustration would be used on a diesel engine to __________. MO-0031
take compression and firing readings
On a main propulsion diesel engine, the instrument shown in the illustration would normally be attached to the __________. MO-0031
cylinder blow down valve
Which area of the indicator diagram illustrated indicates the afterburning period in a diesel engine cylinder? MO-0033
K
In the pressure-volume diagram, shown in the illustration, what is indicated to have occurred by the line connecting points “d” and “e”? MO-0035
the combustion gases have expanded
The boiler shown in the illustration would be classed as __________. MO-0064
single-pass, fire- tube, scotch marine
The illustration shown describes a _______. MO-0069
two cycle opposed piston diesel engine
Which of the following statements would apply when checking the valve clearance of the unit shown in the illustration? MO-0074
Cold valve clearance is measured between components “C” and “D”.
When inspecting the valve mechanism shown in the illustration, normal maintenance would include __________. MO-0074
measuring the cold valve clearance between components “C” and “D”
The device shown in the illustration is a __________. MO-0070
hydraulic lash adjuster
The device shown has been removed from an exhaust valve bridge assembly. The function of the illustrated device is to __________. MO-0070
maintain valve lash adjustment
The RPM of “D” is 500 and hobbed with 36 teeth. If gears “A”, “B”, and “C” have 72, 64, and 24 teeth respectively, the RPM of “A” in the gear train illustration is __________. MO-0088
93.75 RPM
The RPM of “D” is 800 and hobbed with 38 teeth. If gears “A”, “B”, and “C” have 80, 62, and 20 teeth respectively, the RPM of “A” in the gear train illustration is __________. MO-0088
122.58 RPM
In the illustration, If gear A has 72 teeth, gear B has 64 teeth, gear C has 24 teeth and gear D has 36 teeth, what is the RPM of the gear D if gear A is turning at 100 RPM? MO-0088
533.33 RPM
The RPM of “A” is 100 and hobbed with 76 teeth. If gears “B”, “C”, and “D” have 60, 32, and 42 teeth respectively, the RPM of “D” in the gear train illustration is __________. MO-0088
339.29 RPM
After a long period of operation, a wear ridge, caused by piston ring action, will develop near the top of the cylinder liner. This ridge must be removed during maintenance in order to prevent __________.
breaking of the rings, ring lands, or both during piston removal
The ring lands on a large, low-speed, main propulsion diesel engine piston may crack due to __________.
insufficient ring groove clearance
The proper location for journal bearing oil grooves is __________.
as a side relief where the two shells meet
The part labeled “G”, as shown in the illustration, is a __________. MO-0040
connecting rod bushing
The part labeled “F” shown in the illustration, is the __________. MO-0040
bearing shell halves
The part labeled “E”, as shown in the illustration, is the __________.
connecting rod cap
The illustration is of a/an __________. Illustration MO-0044
air driven starter motor assembly
The Bendix drive on the starting motor illustrated is indicated by piece number __________. MO-0044
53
In the illustration, pieces #31 and #29, have 16 and 55 teeth respectively. In order to start the engine, the Bendix drive must turn 3000 RPM. Therefore, the air motor assembly must rotate at __________. MO-0044
10312.5 RPM
On the cylinder indicator diagram illustrated, the dotted line indicated as ‘L’ is describing the _________. Illustration MO-0033
cylinder pressure without injection
Which area of the indicator diagram illustrated, indicates the ignition delay period in a diesel engine cylinder? Illustration MO-0033
J
On the cylinder indicator diagram illustrated, the maximum rise in pressure occurs during the period labeled as ______. Illustration MO-0033
H
In the illustration shown, if a crankcase explosion occurs in a diesel engine, which of the following will occur? MO-0105
Spring #11 will be compressed
What is the purpose of the device shown in the illustration? MO-0105
Protect the crankcase from overpressure in the event of explosion.
One method of determining crankshaft misalignment is by __________.
taking micrometer readings between the crank cheeks opposite the crankpin every 90° of crank angle rotation
High-speed, multi-cylinder, diesel engines commonly use counterweights placed opposite to the crankpins to __________.
provide dynamic balance by equalizing centrifugal force
The bearing shown in the illustration is designed to carry thrust when applied
__________. Illustration MO-0001
right to left only
The part labeled “C” of the illustrated bearing is called the __________. MO-0001
Cage
The part labeled “A” of the illustrated bearing is called the __________. MO-0001
inner race
Valve ‘1’, as shown in the illustration when, should be operated when __________. Illustration MO-0077
entering or departing port.
As shown in the illustration, the viscosimeter would be used to directly control the output of which of the following components? Illustration MO-0077
Final heaters.
Fuel injection pumps using the port and helix metering principle requires the use of a __________.
lapped plunger and barrel
The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to __________.
assist in a quick cutoff of fuel injection
