Diesel/Motor Plants Flashcards
A Kingsbury, or pivot shoe type thrust bearing, can bear much greater loads per square inch of working surface than can parallel surface bearings because provisions are made in the Kingsbury bearing __________.
(a) for automatically adjusting clearances to the correct value when wear occurs
(b) for adjusting the filler piece thickness behind the pivotal-shoes to give a more accurate fit
(c) to allow the leveling plates to pivot on the collar when thrust loads are applied
(d) for the shoes to tilt slightly, thereby allowing the formation of a wedge shaped oil film under a thrust load
(d) for the shoes to tilt slightly, thereby allowing the formation of a wedge shaped oil film under a thrust load
Which component of a kingsbury thrust bearing assembly transmits the thrust from the line shaft to the oil film and shoes?
(a) Collar
(b) Lower leveling plate
(c) Upper leveling plate
(d) Base ring
(a) Collar
A four cylinder, four stroke/cycle, single acting diesel engine has a 740 mm bore and a 1500 mm stroke. What indicated power will be developed if the average mean effective pressure is 18 kg/cm2 at a speed of 90 RPM?
(a) 3416 kW
(b) 4644 kW
(c) 7296 kW
(d) 9290 kW
(a) 3416 kW
1764 x 430.08 x 1.5 x 0.75 x 4 = 3414 kW
or 853.5 kW/cyl
18kg/cm2 EMP = 1764kPa (18 x 1764) 740mm bore = 430.08m2 (pi x 370^2 / 1000) 1500mm stroke = 1.5m (1500 / 1000) 90 RPM, 4 stroke = 0.75 (90 / 2 / 60) 4 cylinders
An eight cylinder, four stroke/cycle, single acting diesel engine has a 650 mm bore and a 1400 mm stroke. What will be the developed indicated metric horsepower if the average mean effective pressure is 30 kg/cm2 at a speed of 100 RPM?
(a) 1689 kW
(b) 9,111 kW
(c) 12,388 kW
(d) 24,776 kW
(b) 9,111 kW
30kg/cm2 EMP = 2940 kpa (30 x 98)
650mm bore = area of 331.83m2 (pi x 325^2 / 1000)
1400mm stroke = 1.4m (1400 / 1000)
100RPM, 4 stroke = .833 power strokes/sec (100 / 2 / 60)
8 cylinders
2940 x 331.83 x 1.4 x .833 x 8 = 9101.77kW
The average pressure exerted on a piston during each power stroke is termed __________.
(a) indicated horsepower
(b) mean effective pressure
(c) exhaust back pressure
(d) compression pressure
(b) mean effective pressure
The most important factor in engine performance is the actual power output at the end of the crankshaft available for doing work. This is known as __________.
(a) indicated horsepower
(b) brake horsepower
(c) net horsepower
(d) friction horsepower
(b) brake horsepower
Cooling the intake air supplied to a diesel engine will __________.
(a) reduce mean effective pressure
(b) decrease average compression ratio
(c) decrease air charge density
(d) increase peak power output
(d) increase peak power output
A seven cylinder, 2-stroke/cycle, single acting diesel engine has a 750 mm bore and a 2000 mm stroke. What indicated power will be developed if the average mean effective pressure is 14.8 kg/cm2 at a speed of 96 RPM? A 1,959 kW B 3,906 kW C 14,363 kW D 28,726 kW
C 14,363 kW
14.8 kg/cm2 = 1450.2m2 (14.8 x 98) 750 mm bore = 441.786 (pi x 375^2 / 1000) 2000 mm stroke = 2m (2000 / 1000) 96 RPM, 2 stroke = 1.6 (96 / 60) 7 cylinders
1450.2 x 441.786 x 2 x 1.6 x 7 / 1000 = 14,351 kW
A Tier 2 V-16 Engine, four stroke/cycle single acting diesel engine has a 145mm bore and a 172mm stroke. What will be the indicated horsepower if the mean effective pressure is 19.4kg/cm2 at a speed of 1900 RPM?
1367.43 kW
19.4kg/cm2 MEP = 1901.2 (19.2 x 98)
145mm bore = 16.51m2 (pi x 72.5^2 / 1000)
172mm stroke = 0.172m (172 / 1000)
1900 RPM, 4 stroke = 15.83 (1900 / 2 / 60)
16 cylinders
1901.2 x 16.51 x 0.172 x 15.83 x 16 / 1000 = 1367.43
The heat exchanger plates, used in the device shown in the illustration, are produced from which of the listed materials? Illustration MO-0110 A Titanium B Copper C Anodized aluminum D Phosphor bronze
A Titanium
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? A 75 degrees B 100 degrees C 180 degrees D 320 degrees
D 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? A 75 degrees B 125 degrees C 160 degrees D 320 degrees
C 160 degrees
In the pressure-volume diagram, shown in the illustration, the volume line is divided into 16 units indicating __________. Illustration MO-0035
(a) a cylinder volume of 166 cubic inches
(b) compression pressure is 1600 PSI
(c) a 16 to 1 compression ratio
(d) 16° of crankshaft motion between lines A and B
(c) a 16 to 1 compression ratio
In the pressure-volume diagram shown in the illustration, curve ‘A-d’ indicates __________. Illustration MO-0035
(a) combustion at approximately constant pressure
(b) opening of exhaust valves
(c) fuel injection after dribble
(d) start of fuel injection
(a) combustion at approximately constant pressure
In the pressure-volume diagram, shown in the illustration, what is indicated to have occurred by the line connecting points ‘d’ and ‘e’? Illustration MO-0035
(a) The combustion gases have expanded.
(b) The crankshaft has rotated 90°.
(c) Pressure and volume have increased.
(d) The fuel/air charge is compressed.
(a) The combustion gases have expanded.
In the pressure-volume diagram, shown in the illustration, what occurs between points “e” and “f”? Illustration MO-0035
(a) The exhaust valve closes.
(b) The intake ports close.
(c) Pressure in the cylinder decreases.
(d) Volume in the cylinder decreases.
(c) Pressure in the cylinder decreases.
In the pressure-volume diagram shown in the illustration, fuel injection occurs at point __________. Illustration MO-0035
(a) e
(b) d
(c) f
(d) c
(d) c
Which segment of the two cycle engine diagram shown represents the power stroke? MO-0037 A I B VI C V D IV
B VI
Which segment of the two cycle engine diagram shown in the illustration represents 'supercharging'? MO-0037 A I B II C III D IV
C III
Which segment of the two cycle engine diagram shown in the illustration represents the exhaust event? MO-0037 A I B II C III D IV
D IV
Which segment of the two cycle engine diagram shown represents compression? MO-0037 A I B II C III D IV
A I
In the theoretical diesel cycle, shown in the illustration, which of the listed conditions normally takes place between points "3" and "4"? MO-0036 A Compression B Combustion-constant volume C Combustion-constant pressure D Expansion
D Expansion
If the compression ratio is increased on any diesel engine, __________.
(a) the expansion ratio will decrease
(b) combustion will be slowed down
(c) thermal efficiency will decrease
(d) thermal efficiency will increase
(d) thermal efficiency will increase
The ratio of the brake horsepower to the indicated horsepower of a diesel engine is its __________.
(a) thermal efficiency
(b) mechanical efficiency
(c) brake thermal efficiency
(d) volumetric efficiency
(b) mechanical efficiency