TUNING OF MULTI-VALVE AUTOMOTIVE ENGINE FOR ELECTRICITY PRODUCTION FUELED BY BIOGAS

This study is to modify and tune a multi-valve automotive engine to be used with biogas to produce electricity. A biogas carburetor is designed and installed on the engine. Operating variables including air/fuel ratio, ignition timing, and compression ratio are varied to find the optimal operating point. A Nissan GA16DE 1600 cc 16 valve engine is coupled to a 3 phase 2 pole induction motor to produce electricity. It was found that when the system is operating at 3000 rpm, the optimal setting is at air/fuel ratio of 1.006, ignition timing at 49 o before top dead center, and compression ratio of 11:1 will produce the efficiency of 26.22% and the payback period would be 0.96 year. The engine can also be tuned for maximum output power which reduce the payback period to 0.90 year. In this case, the setting is at air/fuel ratio of 0.885, ignition timing at 44 o BTDC, and compression ratio of 11:1 will produce the efficiency of 25.22%.