Southwest Research Institute® (SwRI®) News
Printer Friendly VersionUnique SwRI-developed procedures and analytical tools to assist vehicle manufacturers in meeting SULEV standards
New methods measure low emissions and evaluate vehicle components
San Antonio -- February 23, 1998 -- As regulations on passenger vehicle emissions continue to tighten, engine and aftertreatment manufacturers are challenged to refine and integrate their technologies to further reduce emissions. Engineers and scientists at Southwest Research Institute® (SwRI®) have developed several new procedures and analytical tools that can aid manufacturers in the development of new control technologies to meet Super-Ultra-Low Emissions Vehicle (SULEV) standards.
"A number of SwRI tools and procedures can help clients measure low emissions and evaluate components to meet tougher emissions standards," says Bruce B. Bykowski, assistant director of the Department of Emissions Research in the SwRI Automotive Products and Emissions Research Division. The recently proposed SULEV standards (120,000 miles) are 0.01 gram per mile (g/mi) of non-methane organic gases, 1.0 g/mi of carbon monoxide, and 0.02 g/mi of oxides of nitrogen. These standards are more than twice as stringent as the ultra-low emissions vehicle (ULEV) standards (120,000 miles) originally proposed in 1991. "If enacted by the California Air Resources Board, the SULEV standards will be implemented on 2004 model year vehicles," says Bykowski.
The new SwRI technologies include:
- A procedure to determine how fuel and lubricating oil additive
formulations affect catalytic converters. Sulfur in fuels and phosphorus in oils can
accumulate on the catalyst and degrade performance such that the vehicle no longer meets
appropriate emissions standards. Tests to determine the effects of fuels and lubricants on
catalysts are currently performed on engines, but engines themselves can cause undesirable
variability in test results. In addition, engines require both fuels and lubricants to
operate, making it difficult to separate the effects of fuel additives from those of oil
additives and vice versa.
Under an internal research program, SwRI developed a bench test apparatus, called the Fuel/Oil Catalyst Aging System (FOCAS®), that tests full-size catalysts using a gasoline fuel burner to generate the temperatures and exhaust gas chemistry found in engines, but in a lubricant-free environment. Using this system, engineers can age catalysts and test different fuel properties without the influence of lubricating oils, if desired. On the other hand, FOCAS can be used to test the effects of lubricating oil by injecting test oil as a fine mist downstream of the burner. Under these conditions, the amounts of fuels and oils, as well as their corresponding additives, can be precisely controlled to evaluate any effects on the catalyst.
- A FLexible EXhaust Engine Rig (FLEXER) that generates a wide
range of feedgas conditions. Aftertreatment technology evaluations typically require a
substantial matrix of vehicle-based emission tests to cover expected feedgas variability
among production engines, production vehicles, and their range of operating conditions. In
addition, vehicle aftertreatment tests can be performed only once each day because the
vehicle starts cold, then warms up, and needs to cool down again before the next test.
SwRI has developed a test cell engine rig designed for rapid adaptability so that engineers can produce a wide variety of exhaust conditions and emission concentrations with little transition time. The test rig uses hardware and software to control both steady-state and transient engine exhaust temperatures, from 30o to 500oC. As many as 20 tests each day can be performed on FLEXER, with a tremendous savings in time and costs.
- A computer that intercepts the engine's electronic control unit
(ECU) commands and substitutes user-programmed commands to provide optimization of engine
exhaust for integration with aftertreatment systems. The increasing stringency of
emissions levels requires that aftertreatment manufacturers continually refine their
products' performance. As regulated vehicle emissions levels decline, the tuning of the
engine exhaust with the aftertreatment system becomes an increasingly important part of
system development.
The SwRI computer-controlled intercept system, called Emissions Reduction Intercept and Control (ERIC), can be used on any light-duty vehicle with electronic controls. To apply ERIC, second-by-second emissions are studied, and a particular control system is targeted. Control and feedback signals in the system are then mapped, the map is analyzed, and driving modes corresponding to the problem emission are identified. The ECU control map is modified in the targeted regions, and the map is programmed into ERIC. SwRI engineers then create a computer program to intercept and modify the engine control signals during the targeted driving modes. Using the ERIC system, the most efficient engine calibration for the aftertreatment system can be identified, and feedback is given to the original equipment manufacturer (OEM) and supplier members of the team for use in product improvement.
For more information about the SwRI SULEV tools, contact Maria Martinez, Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510, Phone (210) 522-3305, Fax (210) 522-3547.
