the master cylinder which can be actuated to open between 540 degree and 720 degree of crankshaft reference angle to reduce the pumping loss and the heat loss through the reverse channel in high speed engine applications the slave exhaust valve will still open until the end of the slave exhaust stroke to expel the cold expansion medium out of the slave cylinder now referring to fig1 a to fig1 h for the structural description of the first embodiment the basic components of the swirl injection type eight stroke engine are labeled as follows the master intake port 101 the master intake valve 112 the master piston 111 the master cylinder 110 the slave intake valve 122 the slave intake port 102 the slave exhaust port 109 the slave exhaust valve 129 the slave piston 121 the slave cylinder 120 the reverse channel 160 the reverse input valve 161 the reverse output valve 162 the first charge channel 130 the second charge channel 140 the first charge input valve 131 the second charge input valve 141 the first charge output valve 132 the second charge output valve 142 the alternating charge cam system 180 the ignition means 118 the fuel supplying means 119 the first embodiment is based on the configuration of 90 degree phase difference it should be noted that the phase difference can vary from 60 degree to 150 degree to operate with the 8 process sequence while sustaining a reasonable fuel efficiency over 35 the 8 process sequence of 90 degree phase difference are shown in operation table 1 while the alternative configurations are demonstrated in operation table 2 and operation table 3 with various phase differences 75 degree and 150 degree now.