APPARATUS AND METHOD FOR RETARDING AN ENGINE WITH AN EXHAUST BRAKE AND A COMPRESSION RELEASE BRAKE

摘要

An apparatus and method for retarding an engine having a cylinder with an exhaust valve, an intake valve, an intake stroke, an exhaust stroke, a compression stroke and an expansion stroke. The apparatus includes an exhaust brake and a compression release brake. The exhaust brake includes a variable exhaust restrictor, a pressure sensor for sensing pressure of exhaust gases and a controller operatively connected to the pressure sensor and to the exhaust restrictor. Opening of the exhaust restrictor is adjusted during operation of the apparatus so exhaust pressure is sufficient to cause exhaust valve float prior to bottom dead center of intake strokes of the cylinder, thereby enhancing operation of the compression release brake.