Abstract:  The research tested the effect of fuel supply parameters on combustion and particle emission characteristics on a diesel engine fueled with neat diesel and blends of polyoxymethylene dimethyl ethers (PODE)/diesel (φPODE=20%). The results showed that the increase of common rail pressure could cause advanced main fuel heat release, higher peak incylinder pressure and higher mean gas temperature; the increased common rail pressure would decrease accumulation mode particle (AMP) emission, but would increase nucleation mode particle (NMP) emission under lightduty mode. The advanced pilot injection timing would lower the pilot fuel heat release, and improve the main injection heat release under low load; the advanced pilot injection timing would effectively reduce the AMP number concentration, but cause obvious NMP number increase. The advanced main injection timing directly shifted the main fuel heat release rate and caused an advanced, increased pressure peak; earlier main injection timing would cause lower AMP number concentration and higher NMP emission under lowduty mode, and obtained opposite results under highduty mode. The introduction of PODE could amplify the positive effect of fuel supply parameters on particle emissions and suppress the NMP emission to a certain extent.

Key words:  diesel engine, polyoxymethylene dimethyl ethers (PODE), incylinder combustion, particulate matter, emission