SI Engine with Direct Injection of Methanol Reforming Products - First Experimental Results

In this paper we describe conversion of the gen-set gasoline-fed carburetor single-cylinder SI engine to the direct-injection version operating with the gaseous hydrogen-rich methanol reforming products, and present the first experimental results. It was found that engine feeding by methanol steam reforming products has a great potential of pollutant emissions mitigation as compared with gasoline. NO_x concentrations in the exhaust gas were reduced by a factor of 7 as a result of the lean combustion and lowering in-cylinder temperatures. Particle mass emissions were mitigated to zero-impact levels. Harmful emissions of the target pollutants THC, CO and the GHG gas CO₂ were reduced by a factor of 6, 25 and 1.5, respectively. The achieved efficiency improvement of the engine fed by the directly injected methanol reformate calculated for primary liquid methanol consumption was found to be in the range of 20-70% (depending on the operating mode) as compared with the carburetor-fed gasoline. Higher values of the improvement were observed at lower engine loads. The in-cylinder maximal pressure and the value of pressure-rise rate were higher under the reformate feeding by 75% and 37%, respectively at the same ignition timing.