Abstract: To increase the fuel efficiency and decrease the emissions of current types of internal combustion engines by improving the burning of leaner fuel mixtures, a novel igniter is provided for each combustion chamber of the engine. The igniter comprises a small external chamber into which small charges of auxiliary fuel are valved, mixed with air, and then rapidly compressed to ignition temperature by a miniature piston or ram. From each of these external chambers a small orifice leads to its corresponding engine combustion chamber. The small size of the orifice restricts the exit flow into this engine combustion chamber of the auxiliary air/fuel mixture, permitting effective compression by the rapid action of the ram.