Observation

This question attracted most of the candidates. However, their response to the various parts of question was poor.  The required responses to parts (a), (b) and (c) of the question are:

(a)       The fuel used in an internal combustion engine should:
-           be volatile;
-           have a high calorific value;
-           be clean;
-           have high ignition temperature for a spark ignition engines and low for
compression ignition engines;
-           be free from corrosive substances.
(b)       Flash point:- This is the temperature at which the vapour given off by fuel when subjected to heating will momentarily ignite when a flame is brought near it.

(c)        (i)         Octane rating:- A measure of petrol’s resistance to knock or detonate.
(ii)        Cetane value: A number assigned to diesel fuel to indicate its resistance to knock or detonate.