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	SwRI develops customized hardware and software for advanced research and development requirements. This plot shows A/F ratio substrate temperatures and interval times.

Because manufacturers of diesel-powered, light-duty vehicles in the United States and Europe face very stringent emissions regulations, thermal management strategies were investigated by engineers at Southwest Research Institute (SwRI) in an effort to optimize overall exhaust treatment system performance.

According to U.S. Tier II, Bin 5 regulations in the United States, diesel vehicles must have the same ultra-low emissions levels as gasoline vehicles. To achieve these requisite NOx and particulate matter (PM) emissions levels, the engine combustion and control systems must synergistically couple with exhaust treatment devices while evolving. A lean NOx trap (LNT) is the likely exhaust treatment device for NOx control in the United States for light-duty vehicles, while diesel particulate filters (DPF) are a certainty best suited for PM control.

Study Outcomes

One of the most effective ways to achieve the U.S. Tier II, Bin 5 and future European emissions for light-duty diesel vehicles is by using a four-way catalyst system consisting of:

• Diesel oxidation catalyst (DOC)

• Diesel particulate filter (DPF)

• Lean NOx trap (LNT) with alternative combustion

  • Low-temperature combustion (LTC)

  • Premixed controlled compression ignition (PCCI)

Optimizing the entire catalyst system thermally during steady-state and transient operations will:

• Achieve fast warm-up during cold start

• Maintain favorable catalyst temperature at light load conditions

• Precisely control temperature for simultaneous sulfur and PM regeneration

A flexible exhaust treatment configuration with exhaust flow control was investigated by SwRI.

Thermal management strategies for exhaust treatment component temperature and temperature gradient by controlling lean and rich conditions of LTC and PPCI, EGR rate, and exhaust flow were demonstrated on a Renault G9T600 engine. A flexible exhaust treatment configuration with exhaust flow control was investigated as well. This flexible system significantly improved thermal management capabilities of the entire four-way catalyst system under various challenging conditions such as cold start and desulfation.

For more information about powertrain control, or how you can contract with SwRI, please contact Jayant Sarlashkar, at jsarlashkar@swri.org, or (210) 522-5506.

powertraincontroltech.swri.org

| Engine and Vehicle R&D Department | Engine, Emissions & Vehicle Research Division | SwRI Home |

Southwest Research Institute^® (SwRI^®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 11 technical divisions.

December 28, 2012