DUAL FUEL - Potential of Combined Combustion of CNG and Diesel Fuel 2013-36-0133
The continuous increase in the price of diesel fuel, the longer availability of CNG and the potential to reduce CO2 enhances the attractiveness to replace diesel fuel by CNG, especially in the aspiring economic markets.
One possibility of this is the portrayal of Dual Fuel operation, using a conventional diesel engine with minor modifications, which can be operated either in diesel or a Dual Fuel (gas/diesel) mode. In this combustion mode, it must be possible to obtain a diesel substitution rate up to a maximum of 90 % and 70% on average, as the actual work indicates.
In order to illustrate the potential of such a concept, tests were carried out on a 4 cylinder, 7 litre commercial vehicle engine, which was equipped for external carburation using commercial CNG components, as well as a development control unit with software functionality designed in-house. The objective of the investigations is the calibration of the engine for Dual Fuel operation by optimizing the injection and combustion parameters to comply with EU6 emission regulations, under stationary and transient conditions.
The difficult conversion of methane, which only takes place at comparatively high temperatures, is the biggest technical challenge.
Energetically, the concept represents a bridging technology to pure CNG operation and can contribute to the quicker development of the CNG infrastructure.