(a) Name in sequential order, the four cycles of a petrol engine.
(b) With the aid of a sketch, describe the first stroke.
(c) State two differences between the four stroke compression ignition cycle and the four stroke spark
Most of the candidates attempted this question and gave the required response correctly. However Part (c) of the question was not correctly responded to by the candidates. The correct response to Part (c) is given in tabular form below.
Operational Sequence
C.I Cycle
S.I. Cycle
i
Induction
Air only
Air/fuel mixture
ii.
Compression
High compression ratio
Low compression ratio
iii
Power
Self ignition
Spark plug ignites the charge
iv
Exhaust
Less poisonous
Highly poisonous
