6.1 State TWO main causes of crankshaft vibration in an internal combustion engine - NSC Mechanical Technology Automotive - Question 6 - 2019 - Paper 1
Question 6
6.1 State TWO main causes of crankshaft vibration in an internal combustion engine.
6.2 FIGURE 6.2 below shows a component that is fitted to the front of the cranks... show full transcript
Worked Solution & Example Answer:6.1 State TWO main causes of crankshaft vibration in an internal combustion engine - NSC Mechanical Technology Automotive - Question 6 - 2019 - Paper 1
Step 1
State TWO main causes of crankshaft vibration in an internal combustion engine.
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Answer
The action on the shaft of unbalanced forces due to uneven weight distribution within the engine components.
The torsional or twisting effect of the power strokes upon the shaft, causing oscillations.
Step 2
Identify the component shown in FIGURE 6.2.
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Answer
The component shown in FIGURE 6.2 is a vibration damper.
Step 3
Label A–F of the component above.
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Answer
A - Crankshaft
B - Crankshaft flange/pulley
C - Secondary flywheel
D - Friction disc/Rubber
E - Friction spring
F - Spring plate/Disc
Step 4
State TWO factors which determine the firing order of an internal combustion engine.
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Answer
The position of the cranks on the crankshaft.
The arrangement of the cams on the camshaft.
Step 5
At what angle are the crankpins of a V8-cylinder engine situated?
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Answer
The crankpins of a V8-cylinder engine are situated at an angle of 90°.
Step 6
Why is an intercooler fitted to a turbocharged diesel engine?
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Answer
An intercooler is fitted to cool the air that has been compressed by the turbocharger, increasing the density of the air for improved engine performance.
Step 7
What is the purpose of a supercharger on an internal combustion engine?
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Answer
The purpose of a supercharger is to fill the cylinder with an increased air pressure that is higher than atmospheric pressure, increasing the compression pressure and volumetric efficiency of the engine, thus improving performance.
Step 8
Identify the type of supercharger/blower in FIGURE 6.7.
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Answer
The type of supercharger/blower shown in FIGURE 6.7 is a centrifugal supercharger.
Step 9
Label A–E of the supercharger/blower above.
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Answer
A - Air inlet
B - Air outlet/Exhaust
C - Casing/Housing/Cover/Body
D - Impeller/Turbine
E - Fins/Vanes/Blades
Step 10
Explain the operation of the supercharger/blower above.
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Answer
The centrifugal supercharger is driven mechanically by a belt from the crankshaft. The impeller moves the air outward through the casing, increasing velocity. The geometry of the impeller helps convert this velocity into pressure, which forces more air into the engine, thereby enhancing combustion.
