SECTION A
(a) The sketch in Figure 2 shows an overhead crankshaft arrangement.
- Name the parts labelled U, V, W, X and Y.
- State three functions of the crankshaft
(b) State twopurposes of valve clearance.
Observation
Candidates’ responses to questions on the overhead crankshaft arrangement were not satisfactory. They found it difficult to name the labelled parts correctly and state the functions of the crankshaft. The solutions to the poorly answered part of the question are given below
(a) (i) U–Rocker arm
V–Thevalve, valve crown, valve head
W– The pushrod
X –Tappet, cam follower
Y–Camshaft, cam, cam lobe
- FunctionsoftheCrankshaft
- Itconvertsthereciprocating(upanddown)movementofthepistontorotarymovement.
- Itsupportstheflywheel.
- Itdrivesthecamshaft.
- It indirectlydrivesthealternator or generator.
- Itindirectlydrivesthewaterpump.
- It indirectly drives the compressor of the air-conditioner.