Question 2
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The sketch in fig. 2 shows an external relief valve.
- Name the parts labelled K, L, M and N.
- Explain how the relief valve functions.
- State two effects on automobile when the valve becomes faulty.
- State what happens in the relief valve during:
- What is the main function of automobile steering ball joint?
- Modern cars are designed with allowance for varying lengths of wishbone arms. What is the purpose of such variation?
Observation
Candidates’ responses to 2(b) and 2(d) were not adequate. The solution to the poorly answered part of the question is given below.
- b.
How the Relief Valve Functions
When the normal operating pressure of the oil is exceeded, the ball is forced from its seat by the excessive pressure and then oil will escape back into the sump. This eventually reduces the pressure in the system
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d.
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What Occurs in the Relief Valve during Engine Idling Speed
Durind idling speed, the relief valve opens slightly
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What Occurs in the Relief Valve during High Engine Speed
Durind high engine speed, the relief valve opens wide.
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What Occurs in the Relief Valve during Engine Idling Speed