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 cranksh... 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 upon the shaft of unbalanced forces that occur during the functioning of the engine.
The torsional or twisting effect of the power strokes upon the shaft, which creates irregular rotational dynamics.
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, which affects the timing of the power strokes.
The arrangement of the cams on the camshaft can also dictate the firing order.
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, enhancing engine efficiency and 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, effectively raising the compression pressure and improving the volumetric efficiency of the engine.
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 operates by being driven mechanically, often using a belt from the crankshaft. The impeller within the supercharger is designed to increase the air pressure as it rotates, thereby compressing the air and pushing it into the engine. This results in continuous airflow, which significantly enhances engine performance.
