Abstract: A ‘Blackburn Cycle’ internal combustion engine has maximised ‘air only’ induction and ‘air only’ exhaust strokes between usual 4 stroke cycles. One or more inlet valves open fully via lever 7 for the alternate ‘air only’ inductions. The travel for the next fuel/air induction through the same inlet valve 13 is varied by variable fulcrum 10 acting on rocker 8 via push rod 11. This gives controllable fuel/air inductions without the need for a throttle. An inlet valve opens twice with one cam form and one cam revolution. Fuel is injected directly into the cylinder as required for the usual 4 stroke cycles between the ‘air only’ cycles.

Abstract: An 8 Stroke and 4 Stroke cycle change engine where alternate ‘air only’ inductions are used under half load provided by alternate opening inlet valves operated by Electro-Magnetic, Electro-Hydraulic or other electrically controlled means and where the electronic control of the inlet valves can also open all inlet valves on all induction strokes to deliver more power in 4 stroke mode. The electronic control also allows for different inlet valve timings for each adjacent fuel/air 4 Stroke cycle and the next ‘air only’ 4 Stroke cycle. Electronic control of the inlet valve timing also allows an ‘air only’ inlet valve to open and admit air during an induction stroke when a fuel/air inlet valve also opens thus admitting a larger volume of air to give increased power in the fuel efficient alternate ‘air only’ 8 Stroke mode.

Abstract: A ‘Blackburn Cycle’ or 8 stroke and 4 stroke cycle change piston engine has a separate fuel/air inlet duct and valve in a cylinder where the throttle means admits a small volume, namely less than 10% of the cylinder capacity, needed for a low idling speed. A separate ‘air only’ inlet duct and valve admits alternate ‘air only’ inductions in each cylinder when less than half load is needed. The preferred plug type of throttle can be disc or cone shaped or shaped to substantially fill the volume between the closed throttle and the inlet valve seat. For higher power the throttle moves away from the inlet valve to open the inlet port. Fuel is injected into the small volume between the throttle and the inlet valve where engine heat helps vaporize the fuel without heating a large mass of the inlet air.