The Operating Features of a Stoichiometric, Ammonia and Gasoline Dual FueledSpark Ignition Engine.

[摘要] An overall stoichiometric mixture of air, gaseous ammonia and gasoline was metered into a single cylinder, variable compression ratio, supercharged CFR engine at varying ratios of gasoline to ammonia.For each combination of load, speed, and compression ratio there is a range of ratios of gasoline to ammonia for which knock-free, smooth firing was obtained.This range was investigated at its rough limit and also at its MBT knock limit.If too much ammonia is used, then the engine fires with an excessive roughness.If too much gasoline is used, then knock-free combustion can;;t be obtained while MBT spark timing is maintained.Stoichiometric operation on gasoline alone is also presented, for comparison. It was found that a significant fraction of the gasoline used in spark ignition engines can be replaced with ammonia.Operation on about 100% gasoline is required at idle.However, a fuel mix comprising 70% ammonia/30% gasoline on a LHV energy basis can be used at WOT.Even greater ammonia to gasoline ratios are permitted for supercharged operation.The use of ammonia with gasoline allows knock-free operation with MBT spark timing at combinations of load and compression ratio which are inaccessible to gasoline.The thermal efficiencies obtained for operation on ammonia with gasoline are as good, or better, than those obtained with gasoline alone, where comparable.The maximum brake thermal efficiency achieved during operation on ammonia with gasoline was 32.0% at 10:1 compression ratio and BMEP = 1025 kPa. The maximum brake thermal efficiency obtained during operation on gasoline alone was 24.6% at 9:1 compression ratio and BMEP = 570 kPa. Engine-out and post-catalyst emissions results are also presented.Engine-out emissions of hydrocarbons and carbon monoxide are replaced with emissions of ammonia when ammonia is used.The harmful emissions produced by an ammonia and gasoline fueled engine can be made to clean up with the same catalytic converter already in use for engines fueled by gasoline alone.The emissions clean-up window is between stoichiometric and 0.2% rich for all ratios of gasoline to ammonia.

[发布机构] University of Michigan

[效力级别] Engineering

[关键词] Ammonia Fuel Spark Ignition Engine Gasoline Efficiency Emissions;Engineering;Applied Physics