HIGH PRESSURE DIRECT INJECTION OF NATURAL GAS IN A DIESEL ENGINE FOR HIGH PERFORMANCE/LOW EMISSIONS
The North American mining industry faces challenging emissions regulations in coming years with the introduction of new standards for off-road diesel engines. In order to remain competitive, industry stakeholders must invest in new technologies that are economically and environmentally sustainable.
Westport Innovations Inc., of Vancouver B.C. has developed high pressure direct injection (HPDI) technology that allows diesel engines to run primarily on natural gas with no intrusive engine modifications, reduced emissions (NOx, PM, CO2) and no loss in performance. This is accomplished through late-cycle high-pressure injection of natural gas into a diesel engine combustion chamber. The natural gas is injected at the end of the compression stroke. A small amount of diesel fuel is injected first to initiate combustion, followed by the main natural gas fuel injection. The diesel cycle and its operating characteristics are fully retained including high combustion efficiency, low speed torque, high-power output, no engine knock and fast response to load changes. Natural gas has been a prohibitive fuel alternative in mining operations due to reduced performance associated with spark ignition and the added weight and space required for compressed natural gas tanks. However, liquefied natural gas (LNG) can be stored in a similar manner and volume to diesel fuel by virtue of its increased energy density over compressed natural gas.
Cummins, Inc. of Columbus, Indiana and Westport have formed a joint venture, Cummins Westport Inc.(CWI), to apply this technology to the Cummins QSK engine series for high horsepower applications such as mine haul trucking. CWI is seeking to develop and test an LNG-fueled HPDI QSK engine in a large mine haul truck to demonstrate low emissions consistent with EPA Tier 3 standards, high efficiency based on HPDI technology and good economics resulting from the high fuel consumption of 2,000+ hp trucks.
emmisions, liquid natural gas, high pressure direct injection, Haul Truck