Engines, Fuels, Lubricants, and Vehicle Systems

The Institute offers internationally recognized development and testing capabilities for engines, fuels, lubricants, and vehicle systems. Innovative design and development services center on engines, engine components, special vehicles, and improved emissions controls. In addition, a full range of fuel and lubricant test services are available for government and commercial clients around the world.

Engine Design and Development

Using internal research results, SwRI developed a real-time oil consumption measurement system based on sulfur dioxide detection and measurement. The system provides discrete oil-consumption measurement for individual cylinders, valve trains, and turbochargers as well as total engine oil consumption.

SwRI is well into a successful, major industry cooperative research program called Clean Diesel III to develop low-emission technologies for diesel engines. The consortium has expanded to 23 members from eight countries representing light- and heavy-duty engine manufacturers, component suppliers, and petroleum companies. The oxides of nitrogen (NO_x) and particulate matter (PM) goals for Clean Diesel III are 0.20 and 0.01 gram per horsepower-hour, respectively. Six technology areas are being investigated at SwRI to meet these ambitious emissions goals by 2003.

Using the Institute-developed Rapid Prototyping Electronic Control System™ (RPECS™), a PC-based tool for real-time powertrain development, SwRI engineers have developed control strategies and experimental hardware for a broad variety of projects for more than 40 clients. To increase RPECS' flexibility, compactness, and ease of use, SwRI engineers, with significant support from the U.S. Environmental Protection Agency (EPA), have developed a compact electronic control unit that features a modular design, with extensive input/output and processing power and customizable drive electronics for a wide variety of automotive actuators.

Because of the tightening of emissions standards and increased power of microprocessors, model-based control has gained considerable attention in the design of engine and automotive control systems. SwRI is working on observer and controller model-based techniques in the control of diesel and gasoline engines. Using these established control system design techniques, engineers are developing optimized, robust control strategies of systems in which high degrees of subsystem interaction occur, such as in the control of exhaust gas recirculation (EGR) on highly boosted engines equipped with variable geometry turbochargers.

Using integrated simulation techniques, Institute engineers predict crankshaft stress and failure of a large reciprocating engine and compressor system. With internal research funding, the Institute developed simulations that integrate multibody dynamics, flexible body components, and hydrodynamic bearing analysis in a comprehensive model of structural behavior.

Automotive system benchmarking involves the characterization of mechanical and electrical aspects of the automotive system. Benchmarking is used to evaluate automotive products that outperform their competition and to create a baseline, a system equivalent in characteristics to the automotive product. This baseline can then be used to develop and add new features to the product. With internal research funding, SwRI engineers are developing a method to characterize the transient behavior of specific automotive engine controller and engine configurations. Building on earlier successes in steady-state algorithm estimation, engineers are working to develop transient control techniques that will help assess hypothesized algorithms. This work supports research projects that require a transient performance baseline to be established and replicated as the basis for further development work.

SwRI has launched an emissions reduction consortium focusing on small, naturally aspirated, diesel engines commonly used in nonroad vehicles such as forklifts, tractors, and front-end loaders. The Naturally Aspirated Tier 3 (NAT3) cooperative research program, consisting of nonroad engine, vehicle, and equipment manufacturers and distributors, will develop emissions reduction technology for naturally aspirated diesel engines of less than 75-kilowatt power levels. The goals of NAT3 are to determine technology to achieve and demonstrate compliance with proposed EPA Tier 3 emissions standards and anticipated European and Japanese emission regulations. Proposed technical projects for the SwRI-coordinated program include direct injection, indirect injection, and homogeneous charge combustion ignition (HCCI) engines.

Emissions Control

One difficulty in achieving the extremely low automotive emission levels required under upcoming federal regulations is the limited efficiency of catalytic converters under cold-start conditions. In an internally funded effort, SwRI developed a novel method of controlling cold-start hydrocarbon emissions from engines fueled by gasoline, natural gas, and propane by installing a small specialty catalyst -- termed the partial oxidation catalyst -- between the engine exhaust ports and the main catalytic converter. The catalyst efficiently converts hydrocarbons under cold-start, rich-exhaust conditions into hydrogen and carbon monoxide. Adding secondary air between the partial oxidation catalyst and the main converter promotes faster activation of the main converter to further lower emissions.

SwRI is applying post-combustion emission control technologies to switcher locomotive engines. Typically ranging from 1,000 to 2,300 horsepower, switcher locomotives are used to move freight cars or short trains within a local area. Exhaust emission regulations for locomotive engines, in effect since 2000, focus primarily on NO_x emissions. Particulate-trap technology originally developed for trucks will be scaled up for locomotive use. Prototype development and testing are being performed on a 2,200-horsepower Electro-Motive Division (EMD) model 16-645E diesel engine, installed in a newly completed SwRI test facility.

Locomotives spend 50 to 75 percent of a typical day at idle, consuming approximately three to four gallons of fuel per hour and continually emitting exhaust pollutants. An SwRI client developed an auxiliary power unit (APU) for locomotives that enables the main engine to be shut down more frequently, reducing diesel fuel consumption and exhaust emissions. Powered by a small diesel engine, the APU can keep the locomotive air system pressurized, the batteries charged, and the main engine water and oil at temperatures sufficient to ensure easy restarting. It can also provide 110 volts of power for all cab appliances. SwRI engineers tested the fuel consumption and exhaust emissions of the main diesel engine and the APU engine as installed in a locomotive. Idle test results showed that using the APU reduced fuel consumption by 88 percent and air pollutants by more than 90 percent.

Aftertreatment manufacturers are developing several control technologies, including oxidation catalysts, to reduce potentially harmful particulate emissions from diesel engines. Diesel oxidation catalysts oxidize some of the hydrocarbon species present in the exhaust or deposited on the particulate, improving overall emissions levels. In a study funded by the Coordinating Research Council and the U.S. Department of Energy, SwRI is assessing the impact of diesel oxidation catalysts on particulate and gaseous exhaust emissions from a state-of-the-art, light-duty, diesel-fueled vehicle. Using a variety of catalyst formulations, SwRI engineers are determining engine-out and tailpipe emissions and particle-size distribution by operating the vehicle on a chassis dynamometer over transient and steady-state driving cycles.

To generate comparative toxicity data from real-world gasoline- and diesel-fueled vehicles, the National Renewable Energy Laboratory (NREL) contracted with SwRI to collect large-mass samples of emitted particles from a variety of vehicles operating on a chassis dynamometer. The samples were submitted to the National Institute for Occupational Safety and the Lovelace Respiratory Research Institute for toxicity tests, and size-segregated particulate matter samples were collected and submitted to the Oak Ridge National Laboratory for morphological analyses. SwRI is also conducting a project for the Office of Heavy Vehicle Technologies of the U.S. Department of Energy (DOE) that uses the sampling systems, collection techniques, and analytical methodologies developed for the NREL study to collect large-mass particle samples from compressed natural gas-fueled, light- and heavy-duty vehicles operating on a chassis dynamometer. The same laboratories used in the NREL program will be used to conduct toxicity testing.

An improperly functioning EGR system can significantly increase vehicle emissions that lead to the formation of ozone -- a major component of smog. The Texas Natural Resource Conservation Commission (TNRCC) wanted to determine if an EGR system function check could be a valuable part of future vehicle annual inspections in Texas counties that fail to meet ambient air quality ozone standards. The Institute conducted EGR function and exhaust emission tests to help the TNRCC evaluate a potentially low-cost annual inspection and maintenance test. Analysis of the SwRI data showed that large emission reductions could be achieved by repairing malfunctioning vehicles identified by an EGR functional check if commercial test equipment can be developed for use by the inspection station.

Fuels and Lubricants Research

An SwRI-developed technique for rating the ignition quality of diesel fuels was incorporated into a new automated device to accurately determine cetane number. The device, called the Ignition Quality Tester (IQT™), has been named one of the 100 most significant technical accomplishments of 2001 by R&D Magazine. Ignition quality, measured by cetane number, is one of the most important combustion characteristics of diesel fuel. Ignition characteristics affect the fuel's ability to ignite during cold-start and the rate of preparation of the injected fuel in the cylinder during the ignition delay period. If ignition delay is long, the burning of the premixed fuel leads to higher combustion temperatures and increased NO_x emissions. For new diesel engines that use EGR, evidence indicates that raising the cetane number may reduce emissions of unburned hydrocarbons when operating in a low-temperature environment.

The Institute routinely conducts a wide spectrum of physical and chemical analyses of fuel samples collected throughout the United States and Canada. This year, SwRI also performed a comprehensive sampling program of gasoline and diesel fuels throughout Mexico. Working with fuel samples from 16 metropolitan areas, the Institute produced the first comprehensive report by an independent organization on the quality of Mexico's gasoline and diesel fuels.

To reduce vehicle emissions and enhance air quality, oxygenated fuels have been introduced into "nonattainment" areas -- those areas within the United States that fail to meet EPA-mandated air quality standards. Because ethanol is a common oxygenate, the Coordinating Research Council (CRC) has been evaluating the effects of ethanol fuel blends on vehicle drivability. During these evaluations, the fuels in the test vehicles were changed from oxygenated to hydrocarbon-only fuels. To address a CRC concern of possible carryover of ethanol resulting from inadequate flushing techniques, Institute researchers evaluated ethanol carryover for three CRC-specified flushing procedures. Institute engineers also developed more effective fuel-flush procedures and evaluated four additional CRC-developed flushing procedures.

For many years, the Institute has evaluated fuel additives by testing a sample in an engine for a significant time and then partially disassembling the engine for a final inspection. Using internal funding, SwRI is developing a single-cylinder engine dynamometer, fuel-additive "screener" test to evaluate a fuel's tendency to form deposits on intake valves and combustion chamber surfaces. With the successful completion of this short-term test, the Institute has provided industry with a more cost-effective procedure to evaluate the depositing characteristics of candidate fuels.

To qualify lubricating oils for locomotive engines, the Institute uses an EMD 2-567C two-cylinder research engine to conduct a 25-hour silver lubricity test. After the test, technicians use the EMD distress demerit procedure to rate the wear and distress of modified engine bearings to determine if the oil meets locomotive requirements.

SwRI has played a key role in developing the next heavy-duty (diesel) American Petroleum Institute engine oil category, currently identified as Proposed Category 9 (PC-9). Heavy-duty engine manufacturers need PC-9 oils to help protect their new engines from the deleterious effects of EGR. These engines are required to meet the 2004 federal emissions regulations two years early, and nearly all of them will use EGR to meet these standards. The Institute has completed several matrices to establish the precision of the new tests in the category. After test results have been analyzed, approval to begin registered qualification testing will begin.

Turbocharged, direct-injection diesel engines are becoming more prevalent in passenger cars in Europe and, to a lesser extent, in the United States. These engines operate at high speeds and high temperatures, which provide a particularly harsh environment for an engine lubricant. The Institute is the first laboratory outside the European Union approved to perform the Volkswagen lubricant specification test, PV 1452. This test procedure assesses the suitability of engine oil for turbocharged diesel engines by measuring piston cleanliness and ring sticking. The procedure is part of the ACEA B4-01 and B5-01 (Issue 2) specifications for service-fill oils for light-duty diesel engines. The Coordinating European Council (CEC) version of the test procedure is designated CEC L-78-T-99, and SwRI is involved in the continuing test development as a member of CEC Working Group PL-078.

SwRI and a client jointly developed a new, automated device to rate the ignition quality of diesel fuel. The Ignition Quality Tester was identified as one of the 100 most significant technical accomplishments of 2001 by R&D Magazine. The apparatus performs a function similar to the industry-accepted cetane engine test but is faster, more accurate, less expensive, and uses less fuel per test.

One of the newest additions to SwRI's testing program is a test stand for testing the efficiency performance of medium- and light-duty rear axles. The test stand evaluates efficiency improvements relative to lubricating oils, axle buildup practices, and axle hardware design choices and is more precise than road fleet evaluations. Axle manufacturers and lubricant additive companies are the beneficiaries of this new capability.

Contamination significantly affects the performance and durability of fuel, air, and lubricant components and systems, especially with respect to automotive safety, vehicle performance, and warranty issues. Using advanced analytical tools, testing techniques, and simulation methodologies, SwRI characterizes various contaminants and assesses the contamination sensitivity of engine and powertrain components.

U.S. Army TARDEC Fuels and Lubricants Research Facility

SwRI operates the U.S. Army Tank-Automotive Research, Development, and Engineering Center (TARDEC) Fuels and Lubricants Research Facility (TFLRF), a government-owned laboratory located on Institute grounds. This facility, staffed by Institute personnel, operates as an in-house component of TARDEC, the Department of Defense organization responsible for military ground vehicle development. SwRI staff members assist the military and other federal agencies in investigating and solving problems with fuels, lubricants, and other vehicular functional fluids, and in conducting research to anticipate future problems.

In its acquisition of aviation turbine fuels, the Defense Energy Support Center (DESC) has encountered numerous filtration problems. The DESC tasked TFLRF to coordinate a program evaluating the science and operational aspects of this fuel-related problem. As a result of this study, the government has developed an improved understanding of the interplay of additives and fuels.

Contamination can cause excessive wear, component failure, or unreliable operation of vehicle systems. Filtration products minimize exposure to these contaminants, reducing maintenance costs and downtime. SwRI engineers and scientists develop new filtration media and techniques for air, fuel, and lubricant filtration systems.

In a study jointly funded by the Department of Energy and the Coordinating Research Council, the TFLRF evaluated options for reducing light-duty diesel engine emissions by modifying the fuel or lubricant used in the engine. Results have shown that reformulation of diesel fuel, such as increasing the hydrogen-to-carbon ratio or using oxygen-containing compounds as diesel fuel constituents, may reduce particulate emissions. Use of these formulations has already reduced certain classes of polyaromatic hydrocarbons identified by the EPA as potential toxic agents.

In a program scheduled for completion in early fiscal year 2002, TFLRF is measuring the effects of jet fuel being contaminated with diesel fuel. This contamination serves to increase the potential for jet fuel deposition. The joint industry- and government-funded cooperative program is analyzing the relation of laboratory-derived deposition results to actual aircraft engine component experience. TFLRF is leading industry efforts to develop a new measurement technique and to standardize an improved test method.

TFLRF, in cooperation with diesel engine and fuel filter manufacturers, is developing an innovative fuel-filtration evaluation procedure to simulate filtration performance in the field. Water contamination, already a severe fuel-related problem, may increase with the use of new fuel additives. TFLRF is continuing to develop improved water separation techniques and evaluation procedures for fuel contamination.

Automotive engineers believe that EGR increases soot in lubricating oils, which may decrease required maintenance intervals and increase engine wear. Industry is developing new oil-filtration products to reduce these higher soot concentrations, and TFLRF is working toward a new International Organization for Standardization (ISO) test method for evaluating soot-removal products.

Vehicle Systems Design and Development

SwRI has developed the RAPTOR™/VSM (Rapid Automotive Performance simulaTOR/Vehicle System Model) for commercial licensing. This modular simulation tool is designed to assess vehicle fuel economy, performance, and emissions in virtual and test cell environments. The graphical user interface enables engineers to configure a virtual vehicle from component and subcomponent models, while the program's database tool provides secure storage, access, and configuration management for all models, data, and results.

SwRI scientists and engineers subject vehicle components, subsystems, and final assemblies to simulated environments to measure performance and longevity and to detect workmanship or production faults. Institute scientists develop test protocols that combine contamination, pressure cycle, thermal cycle, and vibration in a single test, providing near real-world test data in a timely and cost-effective manner.

To support the U.S. Army's goal for improved mobility and effectiveness, the Institute conducted numerous military vehicle simulation studies, evaluating fuel economy improvements for trucks that incorporate a variety of cutting-edge technologies. These technology assumptions include an improved diesel engine, toroidal continuously variable transmission, hybrid powertrain, improved aerodynamics, reduced rolling resistance, and decreased weight. Simulations showed significantly improved hauling efficiency for the military's tactical wheeled vehicles such as the high-mobility, multiwheeled vehicle; medium tactical truck; and heavy-duty transport vehicle.

In examining existing technologies necessary to develop a heavy-duty truck powered by a diesel-reformed fuel cell, Institute engineers investigated the fuel cell, power conditioners, motor controller, drive motors, batteries, chassis, passenger trailer, control hardware and software, and passenger display hardware and software. In this study, funded by the U.S. Army's National Automotive Center, SwRI found that solid oxide fuel cells appear to be most effective for use in JP-8-fueled military vehicles. These fuel cells have carbon monoxide tolerance and utilization, increased sulfur tolerance, no water management requirement, high-quality heat, an inlet temperature better matched to reformer output, high efficiency, and a robust capability.

For an internally funded project, SwRI has developed a comprehensive hardware-in-the-loop test cell system for hybrid, electric, and conventional powertrains that simulates the real-time operation of powertrain components in a laboratory. The system contains three developments. "Genomodeling," a technique for mathematically modeling powertrain components, combines physics-based modeling techniques with real-time data, which allows engineers to modify powertrain component models continuously. The second element allows powertrain components to be optimally designed and controlled based on the required duty cycle. The third is a test cell that allows various powertrain components to be tested under the simulated field conditions. The system can individually test engines, transmissions, hydraulic pumps and motors, batteries, and vehicle accessories. Combinations of components, such as engines and transmissions, also can be evaluated by simulating the control and vehicle systems around the hardware under test.

Using internal research funds, SwRI engineers are developing a hydrodynamic engine simulator to test transmissions and other driveline components. The system has a very low inertia, equivalent to an engine, and the ability to simulate the primary torque fluctuations. This capability makes it possible to test and develop transmissions and their controls for a variety of engines without requiring the actual engines for the test and in parallel with engine development, greatly reducing product development time.

For several years, SwRI engineers have used radioactive tracer technology to measure real-time wear in automotive engines, powertrains, and other mechanical systems. SwRI has extended this technology to investigate corrosion, erosion, and cavitation in oil- and water-based systems and to develop instrumentation for evaluating material response to fluid chemistries and dynamics. Institute engineers are developing procedures, methodologies, and systems that can use this technology to measure crude oil corrosivity.

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