Patent ID: 6971341

Claim:
A free piston engine comprising: an energy generation and control assembly having a first side; a first combustion cylinder assembly located adjacent to the first side of the energy generation and control assembly and including a first cylinder liner that defines a generally cylindrical first engine cylinder, with the first cylinder liner including a plurality of circumferentially spaced oil mist holes extending therethrough; a piston assembly having a first piston located and telescopically slidable within the first engine cylinder and having an outer cylindrical surface adjacent to the plurality of oil mist holes, and a first rod mounted to the first piston and operatively engaging the energy generation and control assembly, wherein the piston assembly is an outer piston assembly, with the first piston having a piston head that faces the energy generation and control assembly and having a rear end; a first scavenge pump engaged with the first combustion cylinder having a first scavenge pump housing, which defines an air inlet, an air outlet and includes a wall that defines a main pumping chamber selectively connectable to the air inlet and the air outlet, and with the main pumping chamber telescopically receiving the rear end of the first piston therein such that the rear end of the first piston seals against the wall of the main pumping chamber and is actuable to create an air pumping action in the main pumping chamber; and an oil mister, adapted to mix oil with air to form an oil mist, and having an oil mist outlet in fluid communication with the plurality of oil mist holes.