FRANK J PEKAR
Engineers in San Luis Obispo, CA

6216667, Apr 17, 2001

Nov 12, 1999

9/438318

Frank J. Pekar - San Luis Obispo CA

F02D 906

123320

The invention relates to a system and method for engine braking a four-stroke internal combustion engine. The engine has for each cylinder at least one inlet valve and at least one exhaust valve for controlling communication between a combustion chamber in the cylinder and an inlet system and an exhaust system, respectively. In addition, each cylinder communicates with an independent high pressure transfer passage via individual transfer valves disposed at each cylinder. The transfer valves, respectively, put each cylinder at the early part of its compression stroke in communication with the high pressure transfer passage that has been filled with high pressure air by another cylinder at the later part of its compression stroke. Opening the exhaust valve to further decompress the cylinder nearing the end of its compression stroke preferably follows this process. To achieve maximum retarding effect, the exhaust valve is only kept open long enough into the expansion stroke to decompress the cylinder and then the exhaust valve is closed so that expansion work takes place in the remaining part of the expansion stroke.