FIGURE 6.1 below shows the crankshaft of a four-cylinder in-line engine - NSC Mechanical Technology Automotive - Question 6 - 2020 - Paper 1
Question 6
FIGURE 6.1 below shows the crankshaft of a four-cylinder in-line engine. Answer the questions that follow.
6.1.1 What is the main function of the crankshaft shown i... show full transcript
Worked Solution & Example Answer:FIGURE 6.1 below shows the crankshaft of a four-cylinder in-line engine - NSC Mechanical Technology Automotive - Question 6 - 2020 - Paper 1
Step 1
What is the main function of the crankshaft shown in FIGURE 6.1?
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Answer
The main function of the crankshaft is to convert the reciprocating motion of the piston into rotary motion. It plays a crucial role in transforming the linear motion from the pistons into the rotational motion required to turn the engine's crankshaft.
Step 2
Label A–G, the parts of the crankshaft, as shown in FIGURE 6.1.
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State TWO firing orders of a four-cylinder in-line engine.
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Answer
The two common firing orders for a four-cylinder inline engine are:
1 – 3 – 4 – 2
1 – 2 – 4 – 3
Step 4
Identify the component shown in FIGURE 6.2.
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Answer
The component shown in FIGURE 6.2 is a turbocharger.
Step 5
Label A–E, the parts of the component in FIGURE 6.2.
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Answer
Label
Part Name
A
Exhaust gas inlet
B
Impeller or turbine
C
Compressed air outlet
D
Turbine housing / Compressor housing
E
Exhaust gas outlet
Step 6
State the main function of the component in FIGURE 6.2.
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Answer
The main function of the turbocharger is to increase the volumetric efficiency of the engine by forcing more air into the combustion chamber, allowing for more fuel to be burned and thus increasing power output.
Step 7
Identify the different types of engine layouts, as shown in FIGURE 6.3.
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Answer
The different engine layouts shown in FIGURE 6.3 are:
A. Inline engine / Straight engine
B. V-engine
C. W-engine / Double V
Step 8
State THREE advantages of a vehicle fitted with both a supercharger and a turbocharger on its engine.
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Outstanding fuel economy due to improved efficiency.
Increased power and torque across the entire engine speed range.
Reduced lag at low revolutions, allowing for better throttle response.
Step 9
State TWO disadvantages of a vehicle fitted with both a supercharger and a turbocharger on its engine.
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Increased power demand from the engine due to the mechanical drive system for the supercharger.
Complexity in engine design with additional components requiring more maintenance.
Step 10
Why are the connecting rods and pistons manufactured as light as possible?
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Connecting rods and pistons are manufactured as light as possible to reduce reciprocating mass or force, enhancing engine response and performance. Lighter components will also reduce engine power loss and help minimize vibrations, leading to a smoother operation.
