A single-cylinder high-compression-ratio engine with the specifications was shown in Table 1. The tested engine was designed so as to enhance thermal efficiency under lean conditions around an excess air ratio λ = 2.0. The in-cylinder tumble flow was enhanced with a long stroke and a customized intake adapter. The fuel used in this study was a high-octane gasoline. The port fuel injection method was used for fueling.
Table 1. Engine specifications.
|Displaced volume||563.3 cc|
|Connecting rod||242.5 mm|
|Number of valves||4|
|Exhaust valve open (at 0.1 mm lift)||68 deg. BBDC|
|Exhaust valve close (at 0.1 mm lift)||24 deg. ATDC|
|Intake valve open (at 0.1 mm lift)||22 deg. BTDC|
|Intake valve close (at 0.1 mm lift)||78 deg. ABDC|