A petrol engine (gasoline engine in American English) is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends (such as E10 and E85). Most petrol engines use spark ignition, unlike diesel engines which typically use compression ignition. Another key difference to diesel engines is that petrol engines typically have a lower compression ratio.