In order to reduce NOx emission from a stationary diesel engine, a new prechamber, which is placed at the center of a cylinder head with a smaller volume, was installed in a single cylinder diesel engine with 170mm bore and 180mm stroke, a fundamental test apparatus was constructed, and it was tested to investigate its potential. As a result, the reduction of prechamber volume which realized rich mixture combustion in the prechamber, enlargement of jet passage area, control of fuel injection timing and reduction of intake air temperature which reduced combustion temperature, were proven to reduce NOx emission.
