Technical Paper
Combustion and Emissions Comparison Between a Diesel and a Dimethyl Ether (DME) Off-highway Compression Ignition Engine
2024-04-09
2024-01-2700
Dimethyl ether (DME) is a promising substitute for diesel as a fuel in heavy-duty engines. This article presents the comparison between a diesel and a DME powered compression ignition engine. The diesel-powered version was initially characterised at range of operating points before being converted to operate on DME. The latter was achieved by replacing fuel system components with bespoke DME-compatible engine parts. An off-board fuel pressurisation and conditioning system was designed to replace the existing high-pressure fuel pump, while maintaining all other engine hardware and components. Comparing the engine performance on both fuels, DME combustion duration was found to be significantly shorter than diesel for the same engine load, lambda, combustion phasing (CA50) and EGR rate. The DME-powered version of the engine was found to produce lower carbon monoxide and higher NOx emissions per unit energy output, compared to its Diesel version.