Heuser, B., Kremer, F., Pischinger, S., Rohs, H. et al., "An Experimental Investigation of Dual-Fuel Combustion in a Light Duty Diesel Engine by In-Cylinder Blending of Ethanol and Diesel," SAE Int. J. Engines 9(1):11-25, 2016, doi:10.4271/2015-01-1801.
This study investigated dual-fuel operation with a light duty Diesel engine over a wide engine load range. Ethanol was hereby injected into the intake duct, while Diesel was injected directly into the cylinder. At low loads, high ethanol shares are critical in terms of combustion stability and emissions of unburnt hydrocarbons. As the load increases, the rates of heat release become problematic with regard to noise and mechanical stress. At higher loads, an advanced injection of Diesel was found to be beneficial in terms of combustion noise and emissions. For all tests, engine-out NOx emissions were kept within the EU-6.1 limit.