Abstract: An engine includes a piston located in a cylinder, an inlet through which at least a portion of fuel for an ignition and combustion is passed into the cylinder, an outlet through which exhaust from the combustion is removed from the cylinder, and an air injector that injects air into the cylinder after the ignition and before exhaust escapes through the outlet. The air injector injects sufficient air to burn out all active matter of the fuel, whereby emissions from the engine are free of active matter of the fuel.