Question 2
(a) The sketch in Figure 1 shows a unit in the spark ignition engine.
(i) Name the unit
(ii) State the purpose of the unit.
(iii) Name the parts labelled P, Q, R, S, T and U.
(b) State three areas that require the use of torque wrench in an automobile.
Observation
Candidates’ responses to questions on this question were not adequate. They found it difficult to identify the engine unit let alone name the state its purpose or name the labelled parts as required. The solutions to the poorly answered part of the question are given below
(a) (i) The unit is a carburettor
(ii) Purpose of the unit
- It meters the fuel mixture to give the correct
air-fuel ratio
- It breaks up or automizes the charge into fine
particles to make it burn quickly.
(iii) Naming parts labelled
P – Throttle valve, butterfly or butterfly valve;
Q – Body, casing or main air tube;
R – Venturi, choke tube or mixing chamber
S – Spray nozzle, nozzle or orifice
T – Petrol inlet or inlet
U – Float chamber or chamber