A combined fuel injection and spark ignition device (40) adapted to be received in an opening to a combustion chamber of an internal combustion engine for injection of fuel into the chamber, the device comprising a passageway (60) through which fuel may pass to enter the chamber, the passageway (60) incorporating valve means (48, 56, 58) to control flow of fuel therethrough and terminating in an electrically conductive nozzle (70) associated with means (82) shaped to deliver injected fuel as a coniform layer (80) directed along the longest possible path before intersecting a surface of the combustion chamber, the device further comprising means (68, 70, 82, 84) for effecting spark ignition of the coniform fuel spray substantially at the location of its injection into the chamber.