Fig. 4 shows the effects of the ABE ratio, spark timing and lambda on the output power of the high-speed SI engine. As can be seen from Fig. 4 (a), either the high-speed SI engine fuelled with pure gasoline, or ABE10, or ABE20, or ABE30, the output power of the high-speed SI engine increased with advancing the spark timing. However, the increase rate of the output power was moderately decreased with continually advancing the spark timing. Obviously, the maximum brake power (MBT) of the