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Enhancement of methanol combustion in a direct injected Diesel engine using catalytically coated glow plugs was examined for platinum and palladium catalysts and compared to a non-catalytic baseline case. Experiments were performed for 6 and 10 brake Kilowatts (bKW) at 2500 rpm. Comparisons were made based on combustion, performance, and emissions including carbon monoxide (CO), oxides of nitrogen (NOx), unburned hydrocarbons (UHC), unburned methanol (UBM), and aldehydes. Results show a decrease in glow plug temperature of 100 K is achievable using platinum catalysts, and 150 K for palladium. Furthermore, the palladium catalyst was found to provide better combustion characteristics than the platinum catalyst. Also, the use of both catalysts produced lower aldehyde emissions, and the palladium reduced NOx emissions as well. However, unburned methanol increased for both catalytic glow plugs with respect to the non-catalytic case.

The effects of platinum and palladium catalysts on the enhancement of methanol combustion were investigated in a high pressure flow reactor and in a single-cylinder, D.I. Diesel engine. Initial studies were carried out in the flow reactor to determine the effect of catalyst temperature and equivalence ratio on the products of methanol combustion. Afterwards, Diesel engine studies were performed with in-cylinder catalysts applied to the exhaust valves in order to maintain high catalyst temperature required for high reactivity. Comparisons were based on performance, combustion characteristics, and emissions. Results of the flow reactor studies show that the catalytic ignition temperature, found to be 570 K, did not vary significantly with equivalence ratio. The Diesel engine experiments revealed that a decrease in glow plug temperature of 400 K was achievable while providing better performance and reduced emissions, including aldehydes, compared to the non-catalytic case.