Abstract: A compression ignition engine is supplied with a first fuel in a flow of air and a second fuel is injected into the combustion chamber. The first fuel comprises a more volatile fuel than diesel such as ethanol, LPG or other combustible gas; the second fuel comprises diesel or biodiesel; and the second fuel is injected in multiple pulses in each ignition cycle with the first pulse acting as a pilot pulse to trigger ignition, and the timing of the second pulse being such as to modify the temperature through evaporation of the second fuel and thereby reduce the combustion temperature and mitigate knock susceptibility. Preferably the pilot pulse is followed by a single further pulse of the second fuel in the ignition cycle.

Abstract: A compression ignition engine is supplied with a first fuel in a flow of air and a second fuel is injected into the combustion chamber. The first fuel comprises a more volatile fuel than diesel such as ethanol, LPG or other combustible gas; the second fuel comprises diesel or biodiesel; and the second fuel is injected in multiple pulses in each ignition cycle with the first pulse acting as a pilot pulse to trigger ignition, and the timing of the second pulse being such as to modify the temperature through evaporation of the second fuel and thereby reduce the combustion temperature and mitigate knock susceptibility. Preferably the pilot pulse is followed by a single further pulse of the second fuel in the ignition cycle.