Patent ID: 6973898
Filing Date: 2005-12-13
Classification: F02B

Abstract:
1. A free piston engine comprising: a fluid pumping assembly having a first side, and a rod bore extending generally parallel to an axis of motion that includes a first end, a second end and a piston stop adjacent to the first end that has a first radially stepped portion and a second radially stepped portion, which is spaced farther from the first end than the first radially stepped portion; a combustion cylinder assembly located adjacent to the first side and including a cylinder liner having a generally cylindrical wall that defines an engine cylinder, which extends generally parallel to the axis of motion; a piston assembly having a piston that is located and telescopically slidable within the engine cylinder, and a rod including a first portion affixed to the piston and a second portion that includes a plunger that is telescopically slidable in sealing engagement with the rod bore and includes a first end and a second end, and with the rod including a first radially stepped portion that is adjacent to the first end of the plunger and is sized to operatively engage the second radially stepped portion of the piston stop, and a second radially stepped portion, which is spaced farther from the first end of the plunger than the first radially stepped portion of the rod, and is sized to operatively engage the first radially stepped portion of the piston stop; and a fluid filling the rod bore around the rod.