piston movement. Fig. 11 shows that moving the bottom point of
the first-combustion cylinder and the actual compression ratio of
the second-combustion cylinder with different start positions.
Although the piston was closer to the bottom dead center
at a 90 !CA BTDC, the actual compression ratio of the
second-combustion cylinder at this CA was less than at a
70–80 !CA BTDC. It was concluded that combustion characteristics
at a 70 !CA BTDC and an 80 !CA BTDC were better than the others.
Fig. 12 shows the burning efficiency of the air–fuel mixture
with different start positions. The burning efficiency did not have
large differences for start positions ranging from 60 to 90 !CA