초록 ▼

An internal combustion engine has electrically controlled hydraulic linkages between engine cams and engine cylinder valves. If it is desired to skip a cam lobe or to modify the response of an engine cylinder valve to a cam lobe, hydraulic fluid is selectively released from the associated hydraulic

An internal combustion engine has electrically controlled hydraulic linkages between engine cams and engine cylinder valves. If it is desired to skip a cam lobe or to modify the response of an engine cylinder valve to a cam lobe, hydraulic fluid is selectively released from the associated hydraulic linkage to permit lost motion between the cam and the engine cylinder valve. Electrically controlled hydraulic fluid valves are used to produce the selective release of hydraulic fluid from the hydraulic linkages. The mode of operation of the engine can be changed (e.g., from positive power mode to compression release engine braking mode or vice versa), or more subtle changes can be made to modify the timing and/or extent of engine cylinder valve openings to optimize engine performance for various engine or vehicle operating conditions (e.g., different engine or vehicle speeds). The valves can be controlled to produce an exhaust gas recirculation event during various operating modes of the engine.

대표청구항 ▼

[ What is claimed is:] [1.] An internal combustion engine comprising:at least one engine cylinder exhaust valve which is selectively opened and closed;a cam having a plurality of lobes synchronized with possible openings of said at least one engine cylinder valve, wherein said plurality of lobes inc

[ What is claimed is:] [1.] An internal combustion engine comprising:at least one engine cylinder exhaust valve which is selectively opened and closed;a cam having a plurality of lobes synchronized with possible openings of said at least one engine cylinder valve, wherein said plurality of lobes include a exhaust lobe, a compression release lobe and an exhaust gas recirculation lobe, and wherein said hydraulic fluid control is responsive to an engine operating mode;a hydraulic linkage containing hydraulic fluid operatively coupled between said cam and said at least one engine cylinder valve for selectively responding to said lobes by causing said at least one valve to open; anda hydraulic fluid control assembly for selectively controlling hydraulic fluid pressure in said hydraulic linkage to selectively modify the openings of said at least one engine cylinder valve in response to said lobes, said hydraulic fluid control being selectively operable to allow said at least one engine cylinder valve to remain completely closed in response to any first one of said lobes and to open in response to any second one of said lobes.