Patent ID: 7806101

Claim:
A two-stage-coordination type eight-stroke engine comprising: a) a master cylinder ( 110 ) and a slave cylinder ( 120 ) for performing the eight-stroke-operation with the 8-process-sequence; said eight-stroke-operation includes the master-intake-stroke, the slave-intake-stroke, the master-compression-stroke, the slave-compression-stroke, the master-expansion-stroke, the slave-expansion-stroke, the master-exhaust-stroke, and the slave-exhaust stroke; said 8-process-sequence includes the master-intake-process, the slave-intake-process, the master-compression-process, the slave-compression-process, the hot-combustion-process, the injection-process, the cold-expansion-process, the slave-exhaust-process; b) said master cylinder ( 110 ) includes a master piston ( 111 ) and said slave cylinder ( 120 ) includes a slave piston ( 121 ), wherein said master piston ( 111 ) and said slave piston ( 121 ) must constructed with a phase-difference between 60 degree and 150 degree to perform the eight-stroke-operation; c) said master cylinder includes fuel-supplying means and ignition means ( 150 ) for initiating the hot-combustion-process; d) said master cylinder ( 110 ) includes a master-intake-valve ( 113 ) for admitting air into the master cylinder ( 110 ) during the master-intake-process; e) said slave cylinder ( 120 ) includes a slave-intake-valve ( 123 ) for admitting air into the slave cylinder ( 120 ) during the slave-intake-process; f) said slave cylinder ( 120 ) includes a slave-exhaust-valve ( 128 ) for expelling a flow of cold-expansion-medium out of the slave cylinder ( 120 ) during the slave-exhaust-process; g) a coordinate-port ( 160 ) and a coordinate-valve ( 161 ) and a coordinate-spring-adjuster ( 162 ) and a camshaft system ( 169 ) for performing the two-stage-coordination; said coordinate-valve ( 161 ) is opened two times in each round of the eight-stroke-operation, wherein the coordinate-valve ( 161 ) is opened for the first time with the force exerted by the high-density-air for at least 5 degree of crankshaft rotation before the completion of the slave-compression-stroke, next the coordinate-valve ( 161 ) is opened for the second time with the camshaft system ( 169 ) after the slave piston ( 120 ) has started the slave-expansion-stroke.