US Patent 11698022 Modified cycle two-stroke engine

Two-stroke engine includes a cylinder having a peripheral wall defining an interior space, a crankshaft coupled to a piston movable in the cylinder and having a power stroke in which air/fuel in the interior space is ignited and the crankshaft is rotated and a compression stroke, two intake conduits leading to the cylinder, and intake valves in the intake conduits that regulate air flow into the interior space. An exhaust conduit leads from an opening in the peripheral wall between lowermost and uppermost positions of the piston. An exhaust valve is in the exhaust conduit. In an exhaust-intake stroke after the power stroke when the piston has moved such that its upper surface is below the opening, the outlet valve opens, and air is inlet into the interior space through the intake valve(s) and forces combustion products to exhaust the interior space into the exhaust conduit.