Abstract:

Combustion, emission characteristics and thermal efficiency were investigated under various
induced injection-timing for a Homogeneous Charge Induced Ignition (HCII) to improve the thermal efficiency
and reduce soot emissions from under-mixing induced diesel. The tests were conducted in an HCII principle
engine using 0%, 50% and 100% volume friction polyoxymethylene dimethyl ethers (PODEn) /diesel blend as
induced fuel. The results show that adding PODEn can significantly reduce the hydrocarbons (HC), nitric oxide
(CO) emissions, and the Coefficient of Variation (COV) and can increase indicated thermal efficiency at the
condition of 1 200 r/min, 0.3 MPa of Indicated Mean Effective Pressure (IMEP), the HCII induced by 100%
PODEn even has higher thermal efficiency than diesel Direct-Injection mode; and that adding PODEn can significantly
reduce exhaust smoke and increase indicated thermal efficiency at the condition of 1 600 r/min, 0.6 MPa of IMEP.

Key words: diesel engines, combustion, emissions, homogeneous charge induced ignition (HCII), polyoxymethylene dimethyl ethers (PODEn), induced injection-timing