초록 ▼

The present invention is a variable compression ratio engine which can operate both in a Miller cycle and a normal cycle, and which can produce a high output, reduce the generation of NOx, and prevent the occurrence of knocking. For this purpose, the engine is provided with an exhaust gas recirculat

The present invention is a variable compression ratio engine which can operate both in a Miller cycle and a normal cycle, and which can produce a high output, reduce the generation of NOx, and prevent the occurrence of knocking. For this purpose, the engine is provided with an exhaust gas recirculating device equipped with a first cam shaft (10), provided with cams (11, 12, 13) for operating an intake valve (2) and exhaust valves (4, 5), and a second cam shaft (20), provided with cams (21, 22) for operating at least one intake valve (3) and an exhaust valve (5) to thereby recirculate part of exhaust gas into intake gas.

대표청구항 ▼

A variable compression ratio engine for operating in a first condition under a heavy load and in a second condition under a light load, said engine comprising: at least one cylinder chamber; at least one piston, each piston being positioned in a respective cylinder chamber; first and second intake v

A variable compression ratio engine for operating in a first condition under a heavy load and in a second condition under a light load, said engine comprising: at least one cylinder chamber; at least one piston, each piston being positioned in a respective cylinder chamber; first and second intake valves per cylinder chamber; at least one exhaust valve per cylinder chamber; a first cam shaft provided with cams for opening and closing said first intake valve and said at least one exhaust valve; a second cam shaft provided with cams for opening and closing said second intake valve and at least one of said at least one exhaust valve; and a device for changing a phase, between cams on said second cam shaft and cams on said first cam shaft, between a first phase for operating in said first condition under a heavy load and a second phase for operating in said second condition under a light load; whereby a compression ratio of said engine can be changed by changing a timing of the opening and closing of said intake valves and/or said at least one exhaust valve; whereby, in an intake stroke during said first condition under a heavy load, said device sets said intake valves to close at a time before the respective piston is at a bottom dead center of its cycle, and said device sets at least one of said at least one exhaust valve to open and close at times when the respective piston is in the vicinity of a top dead center of its cycle; and whereby, in an intake stroke during said second condition under a light load, said device sets at least one of said intake valves to close at a time when the respective piston is in the vicinity of the bottom dead center of its cycle, and said device sets at least one of said at least one exhaust valve to open and close at times before the respective piston is at the bottom dead center of its cycle so as to recirculate part of the exhaust gas from said cylinder chamber into intake gas for said cylinder chamber.