Southwest Research Institute® (SwRI®) News
Printer Friendly VersionTechnical breakthroughs reported in the use of natural gas in locomotives
Reduction of locomotive emissions is goal
San Antonio -- May 10, 1996 -- Engineers at Southwest Research Institute (SwRI) in San Antonio recently reported to members of the GasRail USA consortium that they have made significant technical breakthroughs in natural gas locomotive engine design.
"The specific goals of the project are to significantly reduce nitrogen oxide (NOx) emissions, without increasing other emissions or reducing fuel economy and power output," says project manager David P. Meyers, a senior research engineer in SwRI's Engine and Vehicle Research Division.
"The program is part of a broad national effort by railway and energy companies to reduce locomotive exhaust emissions. In addition, fuel costs have always played a major role in railroad economics, and LNG shows promise as a fuel with lower costs and more stable prices than diesel fuels," he adds.
After evaluating a number of potential combustion systems appropriate for LNG applications, SwRI engineers have selected a 'late cycle high-injection pressure combustion system,' termed LaCHIP, to test and develop in the second phase of the program; the phase will include the installation and demonstration of an engine in a commuter locomotive. The LaCHIP combustion system supplies a unique gas-diesel hybrid technology and meets program goals in terms of emissions, efficiency, and operational considerations.
"A major problem that needed resolution in this program," comments Meyers, "was the quest for an acceptable gas injector." In the past, diesel-engine conversions using direct-injection of natural gas have been plagued by injector failures in performance and durability. To overcome these difficulties, SwRI engineers worked with Moog Controls, a leader in electro-hydraulic control systems in Buffalo, New York, to custom manufacture a direct-injection gas injector. The injector provides superior performance and flexibility over other models.
"By varying the injector tip parameters to provide greater penetration and better air utilization within the cylinder, we were able to achieve lower NOx emissions without sacrificing power or engine efficiency," Meyers explains.
According to SwRI Senior Research Engineer John Kubesh, the use of computational fluid dynamics (CFD) modeling made an important contribution to the new tip design. CFD modeling allows rapid evaluation of different injector tip designs and configurations to facilitate arriving at an optimum solution. Previously the design evaluation process would have required large and time-consuming experimental efforts.
GasRail USA, coordinated by SwRI, grew out of the Institute's extensive experience in developing heavy-duty engines that operate on natural gas and other alternative fuels. The research and development phases of the GasRail USA project include both single and multicylinder engine development, and the integration of an LNG-fueled engine and its associated fuel storage and handling systems into a passenger locomotive. Following integration, practical on-track demonstrations of the passenger locomotive will be conducted in Southern California by the Southern California Regional Rail Authority.
GasRail USA, a multi-year, cooperative industry research project, was initiated by SwRI in 1993 to develop natural gas engine technology for U.S. railroad freight and passenger locomotives to demonstrate that the use of liquefied natural gas (LNG) fuel contributes to lower emissions.
Participants in the program represent a wide range of organizations: the federal government, state agencies, freight and passenger railroads, original equipment manufacturers, and the natural gas industry. Members have included the Department of Energy, the South Coast Air Quality Management District, the Southern California Regional Rail Authority, the California Air Resources Board, the Union Pacific Railroad, the Electro-Motive Division of General Motors, the Southern California Gas Company, and the Gas Research Institute.
Participating organizations attend quarterly project review meetings at SwRI and receive monthly progress reports; all data are considered proprietary. Each member offers project direction through a representative appointed to an advisory committee. Any company interested in program participation is invited to apply.
Related press release: GasRail
USA reduces NOx by 75 percent
For more information about the GasRail USA consortium, please contact Deborah Deffenbaugh, Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510, Phone (210) 522-2046, Fax (210) 522-3547.
