
76 LIGHT AND HEAVY VEHICLE TECHNOLOGY
With the diesel operating cycle it thus becomes poss-
ible to ignite a spray of finely atomized, but non-
volatile, fuel without the aid of an electric spark. It
does,
however, mean that the compression ratios for
diesel engines must be made appreciably higher than
those adopted for petrol engines, and they generally lie
between 16:1 and 22:1. If compression ratios as high as
these were attempted in petrol engines, then the highly
volatile charge of air and fuel admitted during the
induction stroke would detonate and burn uncontrol-
lably. Fortunately, no such limitation applies to the
diesel engine, becaus ...