While electric cars are starting to gain a following, the
vast majority of the cars on the road today are still powered by internal
combustion engines. The two main types of
engines used for automobiles are gasoline engines (spark ignition) and diesel
engines (compression ignition). One of
the main differences is that in a spark ignition engine a mixture of air and
gasoline fumes is compressed, and lit off by a spark at the appropriate
time. In a compression ignition engine,
on the other hand, only air is compressed and a fine mist of diesel fuel is
injected into the hot air at the appropriate time.
