Southwest Research Institute (SwRI) engineers recently reported to members of the GasRail USA cooperative industry research project that they have achieved a 75 percent reduction in oxides of nitrogen (NOx) emissions on a 4,200 horsepower, 16-cylinder, natural-gas-fueled engine for use in passenger locomotives. The reduction is in comparison to a diesel-fueled engine.
GasRail USA was initiated in 1993 by SwRI, together with federal, state, and industrial participants. Their goal was to develop natural gas engine technology for locomotives and to demonstrate that using liquefied natural gas (LNG) fuel could contribute to lower NOx emissions. SwRI has extensive experience in converting heavy-duty diesel engines to natural gas and other alternative fuels.
"These emission levels make using LNG an attractive proposition for rail companies in noncompliance areas such as Southern California and parts of the Northeast, where diesel locomotives are an important feature of public transportation and contribute substantially to air pollution," says David Meyers, a group leader in SwRI's Engine and Vehicle Research Division and GasRail USA project manager. "A locomotive engine that produces approximately 12 grams of NOx per horsepower hour (g/bhp-hr) using diesel fuel only produces 2.8 g/bhp-hr using this new LNG engine technology.
"There is a small (8-10 percent) penalty in efficiency compared to diesel with the 75 percent reduction in emissions," adds Meyers, "but a 50 percent reduction in NOx can be achieved with no loss of efficiency. An additional benefit is that this engine creates no accompanying increases in carbon monoxide (CO) or hydrocarbon (HC) emissions. Carbon dioxide (CO2) emissions are actually reduced by 25 percent."
Six different LNG engine combustion systems were designed, tested, and evaluated for the GasRail program. The selected system, known as LaCHIP (Late Cycle High Injection Pressure), uses small amounts of diesel fuel as an ignition source for the high-pressure natural gas that is injected late in the combustion cycle. Diesel can also be used as an emergency fuel, allowing the locomotive to pull into a shop for repairs if the LNG supply is interrupted.
The LNG system will be field tested in a Metrolink commuter locomotive owned by the Southern California Regional Rail Authority. Test runs between San Bernadino and Los Angeles in early 1999 will provide additional data on environmental and economic benefits, as well as prove LNG safety procedures.
The Environmental Protection Agency (EPA) in 1997 called for locomotives to meet a 25 percent reduction in NOx emissions and a 40 percent reduction in HC and particulate matter emissions by the year 2000, with further reductions to follow by 2005. Current unregulated diesel locomotive emissions are estimated to contribute five percent of the national total emissions of NOx.
"This LNG technology will be easily transferable to heavier freight engines, where emissions are also of concern," says Senior Engineer John Hedrick. "We are confident that the system is capable of meeting stringent emissions standards in combustion-powered locomotives without resorting to electrification."
SwRI engineers are currently working on the integration engineering phase of the prototype multi-cylinder engine. "Tasks before installation in the test locomotive," says Hedrick, "include working on the transition phases between idle and full-power and evaluating the fuel-switching technology from gas to diesel and vice versa."
Program participants in the GasRail USA program have included the Southern California Regional Rail Authority, the California Air Resources Board, the Southern California Air Quality Management District, the U.S. Department of Energy, the Gas Research Institute, Union Pacific Railroad, Amoco, and General Motors' Electro-Motive Division.
New members are welcome to join the consortium. For further information about GasRail USA, contact David Meyers at (210) 522-5581 or email@example.com.
An innovative compression ignition engine system is being developed at SwRI that reduces engine-out oxides of nitrogen (NOx) emissions by more than 98 percent. Engineers in the Engine and Vehicle Research Division are working to convert a multi-cylinder diesel engine to work with this system, known as homogeneous charge compression ignition (HCCI).
"Emissions from engines have been significantly reduced in the past two decades, but more emissions reductions are necessary," says Bill Gray, a research engineer in the Engine Research Department.
Emissions from diesel engines contribute to ground-level ozone formation, which can cause respiratory problems. As a result, the Environmental Protection Agency will continue to tighten emissions standards for stationary and mobile diesel engines between 1999 and 2008. These pending emissions standards will require a greater than 50 percent reduction in NOx emissions from today's controlled levels.
"In HCCI combustion, the air and fuel are mixed so that each droplet of fuel is surrounded by more than twice the amount of air necessary for combustion," Gray said. "As this mixture is compressed in the cylinder, the air temperature rises until it spontaneously ignites the fuel droplets."
Combustion is then initiated at many locations in the evenly distributed mixture. This combustion takes place with an overabundance of fresh air and occurs at a much lower temperature. Consequently, NOx emissions are reduced by 98 percent.
In spark-ignition engines, a spark plug ignites a mixture of fuel and air, creating high temperatures and resulting in high NOx emissions. In conventional diesel engines, air is drawn into the cylinder and compressed. The start of combustion is controlled by the injection of fuel into the hot, compressed air. This system creates a flame pattern that produces two zones -- a high- temperature combustion zone that yields NOx emissions and a fuel-rich zone with particulate emissions.
The Electromagnetic Compatibility (EMC) Research section of Southwest Research Institute's (SwRI) Automation and Data Systems Division was recently qualified by the American Association for Laboratory Accreditation (A2LA) as meeting ISO 9002 registration and ISO/IEC Guide 25 (European Norm 45001) accreditation.
The International Organization for Standardization (ISO) developed the ISO 9000 series of standards in 1987 to help systematize varying national and international standards that establish the basic requirements necessary to document and maintain an effective quality system. ISO 9002 provides the framework for an overall quality system in production, installation, and services, while ISO/IEC (International Electrotechnical Commission) Guide 25 provides specific guidelines to ensure that accurate data are generated, test methods are controlled and appropriate, and all procedures are conducted only by properly trained personnel.
"I'm proud of the hard work our group invested in this accreditation and their careful attention to documentation and test procedures,"said Jim Polonis, manager of the section. "Every one of our 10 members is certified by the National Association of Radio and Telecommunication Engineers Inc. as an engineer or technician. This registration and accreditation assures clients that we are qualified to assist them with their EMC design test and analysis needs at the very highest level."
SwRI's EMC testing program, begun in 1956, originally focused on military and TEMPEST testing. Later work for the private sector has included testing components that range from heart implants to avionics, space satellite equipment, and shipboard electronics.
The growth in EMC testing of automotive components has grown significantly. As vehicles have become more dependent on electronic components, industry has recognized the importance of ensuring the components operate without malfunction in the presence of RF energy radiated by, for instance, cellular phones, mobile radios and FM, AM, and TV broadcast signals.
SwRI's EMC laboratory is equipped with eight shielded enclosures, including an RF anechoic chamber and a large shielded enclosure with radiated and conducted emissions measurement instrumentation. The Institute also has an FCC-listed open area test site (with a 23 x 40-meter ground plane within a 150-meter elipse) that is level and clear of electromagnetic reflecting surfaces for a minimum radius of 32 meters.
"Having this certified level of service for EMC testing enhances capabilities across the Institute," said Polonis. "For example, if a client has a telecommunications program underway with our Environmental Science group and Fire Technology Department, SwRI can also provide the EMC services for BELLCORE 1089 testing. One-stop service can be very advantageous to our clients."
SwRI has completed a $2.2 million expansion to its vehicle systems research facility, enhancing its transmission, filtration and contamination, hydraulics, and conventional and hybrid vehicle design, development, and testing.
The improvements expand SwRI's independent transmission testing and development facility and provide for evaluation under various duty cycles, with emphasis on component matching, performance enhancement, component sensitivity, and endurance evaluation. The facility also contains a new, state-of-the-art air filtration testing facility for evaluating both automotive and air filters, and a liquids contamination research facility for both hydraulic and fuel systems evaluations.
SwRI's hydraulic component evaluation facility is expanded to include pump/motor performance, efficiency, and durability testing, as well as a new flow test facility for component evaluations. Finally, the facility expands SwRI's conventional, electric, and hybrid vehicle development capability, including the ability to test hybrid vehicle components such as drive motors and batteries. Plans continue to be developed for additional noise testing capabilities and contamination research and development facilities.
The number of transmission test stands has been increased to a total of six high-horsepower electric dynamometer test stands, including one for four-wheel drive or all-wheel drive vehicles in the 4,000-square-foot addition to SwRI's existing vehicle research and development facility. "This facility is designed to handle the increased transmission activity necessary to develop future vehicle drivetrains," says Gary Stecklein, director of the Department of Vehicle Systems Research within SwRI's Engine and Vehicle Research Division.
A 1,000-square-foot air filter test facility incorporates state-of-the-art air conditioning and monitoring equipment, improving the ability to control test conditions beyond the requirements specified by the Society of Automotive Engineers.
Several test stands have been developed and integrated into a new fuel system contamination research laboratory as part of the overall expansion. SwRI can now simulate fuel system contamination operation in these laboratories and provide accelerated testing capabilities which have been proven to replicate field operation conditions. Additionally, high-pressure hydraulic contamination testing and evaluation is enhanced by incorporating computerized data acquisition and control.
Significant investment has also been made to expand hydraulic system development and testing activity. Pumps used in transmissions and off-highway applications now can be tested and evaluated for performance, efficiency, and durability in any of six test stands in the expanded facility. Additionally, a hydraulic flow facility is being developed to evaluate hydraulic components.
SwRI also is investing in conventional, electric, and hybrid vehicle research, development, and evaluation. "We have just completed our first fuel cell test stand and are undertaking R&D to improve fuel cell performance through pulsatile operation," reported Stecklein.
"We have procured a high-capacity power electronics driver to allow us to evaluate batteries and other electric energy storage devices, and we have developed drive motor test stands to evaluate the performance of these hybrid vehicle drivetrain components." The expansion has afforded more space to support conventional vehicle research and development activity, particularly in the areas of suspensions, brakes, starters, alternators, and air conditioner development and evaluations.
Also expanded are the design and analysis capabilities associated with these automotive components. The number of Pro-ETM computer-aided design stations has increased to nine, and capabilities in finite element thermal and stress analysis, kinematic analysis, and computational fluid dynamics analysis have expanded.
Currently, significant design and analysis work is being performed on transmissions, hydraulic pumps and motors, and hybrid drivetrains.
The U.S. Nuclear Regulatory Commission (NRC) recently renewed a contract with SwRI to continue providing technical assistance in licensing a proposed geologic repository in Nevada for 70,000 tons of high-level radioactive nuclear waste. The $87.6 million renewal authorizes the Institute to operate the Center for Nuclear Waste Regulatory Analyses (CNWRA) for another five years.
The CNWRA is helping the NRC establish and implement regulations and related guidance that will govern the licensing of an underground repository at Yucca Mountain, Nevada, intended to safely contain spent nuclear reactor fuel and other wastes for a period of 10,000 years and beyond.
The CNWRA supports the NRC by developing criteria and methods to evaluate the Department of Energy (DOE) site characterization, as well as design, construction, operation, and ultimate closing of the proposed repository. The CNWRA staff will also assist the NRC in determining the adequacy of the DOE license application for the site.
In recent years, the CNWRA has extended its role to assist several foreign countries in developing regulatory procedures and technical methods for evaluating their candidate high-level waste repository sites.
Published in the Spring 1998 issue of Technology Today®, published by Southwest Research Institute. For more information, contact Joe Fohn.