The Effect of Boost Pressure on the Engine Performance by Using a Small Hydrogen Fuelled Engine with Direct Injection in the Early Compression Stroke

摘要

To evaluate the effect of boost pressure, hydrogen gas was directly injected at 7 MPa into the combustion chamber of a small spark ignition engine in the early compression stroke while running the engine with the boost pressure applied from the outside from 1 to 2 atm and the air excess ratio λ from 1.3 to 4,7 at 2000 rpm. Electronic controlled injectors were made for this experiment. A comparison was made on the engine performance while the engine was operated with internal mixture formation in the early compression stroke changing the boost pressure from 1 to 2 atm. There found no abnormal combustion throughout this experiment and the engine operation with NO{sub}x less than 10 ppm was attained over the half load with no exhaust gas aftertreatment system. It has been confirmed in this experiment that the higher the boost pressure is, the greater the output power is with a small NO{sub}x concentration less than 10 ppm. Good air-charging boosters are eagerly desired.