Southwest Research Institute® (SwRI®) News
Printer Friendly Version
Unique SwRI-developed procedures and
analytical tools to assist vehicle manufacturers in meeting SULEV standards
New methods measure low emissions and evaluate vehicle
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
- 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
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
For more information about the SwRI SULEV tools, contact
Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio,
Texas 78228-0510, Phone (210) 522-3305, Fax (210) 522-3547.