Browse Publications Technical Papers 2010-01-1489

Controlling the Heat Release in HCCI Combustion of DME with Methanol and EGR 2010-01-1489

The effects of methanol and EGR on HCCI combustion of dimethyl ether have been tested separately in a diesel engine. The engine was equipped with a common rail injection system which allowed for random injection of DME. The engine could therefore be operated either as a normal DI CI engine or, by advancing the injection timing 360 CAD, as an HCCI engine. The compression ratio of the engine was reduced to 14.5 by enlarging the piston bowls.
The engine was operated in HCCI mode with DME at an equivalence ratio of 0.25. To retard the combustion timing, methanol was port fuel injected and the optimum quantity required was determined. The added methanol increased the BMEP by increasing the total heat release and retarding the combustion to after TDC. Engine knock was reduced with increasing quantities of methanol. The highest BMEP was achieved when the equivalence ratio of methanol was around 0.12 at 1000 RPM, and around 0.76 at 1800 RPM.
EGR was also used to retarding the timing. With a moderate amount of EGR the effect on the combustion was not notable, but as the equivalence ratio approached unity the combustion was increasingly delayed and the rate of reaction reduced. Engine knock seized entirely as the EGR ratio was increased above 60 %. The BMEP gain was however moderate, since lower cylinder pressures at higher EGR quantities counteracted the positive effects of combustion timing.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Comparison of Fuel Effects on Low Temperature Reactions in PPC and HCCI Combustion


View Details


Influence of Injection Strategies on Engine Efficiency for a Methanol PPC Engine


View Details


Pressure Sensitivity of HCCI Auto-Ignition Temperature for Gasoline Surrogate Fuels


View Details