United States Patent [19] [11] Patent Number: 5,606,938 Rowe [45] Date of Patent: Mar. 4, 1997 [54] TRI-LOBED CAM ENGINE [75] Inventor: John A. Rowe, Whitby, Canada [73] Assignee: Tritec Power Systems Ltd., Toronto, Canada [21] Appl. No.: 578,297 [22] Filed: Dec. 26, 1995 Related U.S. Application Data [63] Continuation-in-part of Ser. No. 265,357, Jun. 24, 1994, Pat. No. 5,529,029. [51] Int. Cl.6....................F02B 75/22 [52] U.S. Cl...........123/54.3; 123/55.3 [58] Field of Search..........123/54.3, 55.3, 123/55.7, 197.1, 54.2, 55.1 [56] References Cited U.S PATENT DOCUMENTS 793,270 6/1905 Blomgren ....................123/55.3 1,309,257 7/1919 Martens ...................123/54.3 1,792,062 2/1931 Barnum ....................123/55.3 1,810,688 6/1931 Toce et al ................123/55.3 1,965,548 7/1934 Hart ......................123/54.3 2,124,604 7/1938 Bidwell ...................123/55.3 3,584,610 6/1971 Porter ....................123/55.3 4,038,949 8/1977 Farris ....................123/54.3 4,697,552 10/1987 Kolev ....................123/55.3 FOREIGN PATENT DOCUMENTS 46-42527 12/1971 Japan .....................123/54.3 Primary Examiner - David A. Okonsky Attorney, Agent or Firm - Kenneth M. Garrett [57] ABSTRACT In an engine having free floating reciprocating pistons each with a cam follower which bears on a tri-lobed cam, the pistons are arranged in one or more banks of four pistons each of which extends over an angular interval of 90°. Where two banks of four pistons are utilized, the banks may be separated by an angular interval of 30° or 90°. The tri-lobed cam may be sinuously shaped with different profiles according to the desired characteristics of the engine. 16 Claims, 10 Drawing Sheets