Effects of Pre-chamber Specifications on Engine Performance at Lean Burn Operation in a Pre-chamber Engine with Fuel Reformed Gas

Abstract

In order to improve thermal efficiency while keeping extremely low NOx emissions of spark ignition engines, a new combustion technique which combined pre-chamber combustion with fuel reforming has been proposed and verificated by engine bench tests. In this report, for the purposes of investigating for the effects of pre-chamber specifications on combustion in pre-chamber and main chamber, specifications of prechamber nozzles were varied and the engine performance was evaluated on a single cylinder pre-chamber gasoline engine. As results, effects of pre-chamber specifications were clarified, combustion characteristics in pre-chamber and main chamber were improved, and stable operable regions was extended up to lambda 3.0. Comparing to the normal SI combustion mode, thermal efficiency was improved up to 17%, NOx emission was reduced to under 0.1g/kWh.