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A full size V8 demonstrator was developed to exhibit technology required to target LEV II emission levels. The testing involved the system integration of a vacuum-insulated catalytic converter (VICC) technology, air gap exhaust components, optimized catalyst loading and control system and calibration. The development strategy utilizes the vacuum insulation, phase-change thermal storage capacity, and cold start calibration strategy to enable the catalyst to quickly reach light-off in 6 seconds over the FTP-75. All emission testing was conducted with two LA4 preparation cycles. This approach is able to reduce the heat loss of the catalytic converter brick during a 12 hour soak period and optimize the calibration warm-up strategy to reduce the amount of emissions during the first 60 seconds of the FTP-75. The vehicle used for the demonstration was a BMW 540I application. The modifications to the vehicle were limited to the control system, engine calibration and aftertreatment.

Development of integrated engine controls, exhaust components and advanced catalytic converters was demonstrated on a 1998 full size luxury sedan with a gasoline PFI 4.4 L V8 engine. This level of emissions management was targeted for ULEV and SULEV emission standards. An air gap, dual exhaust, six-catalyst system, was modified in stages to reduce the number of catalysts and associated controls/hardware. Engine controls and calibration were developed to reduce cold-start emissions, catalyst light-off time and tailpipe emissions. Systems integration involved reduced precious metal loading, secondary AIR and modification of emission control devices. The thermal mass of the air gap exhaust pipes was reduced by approximately 30 percent, which contributed to improved catalyst heat-up time. A vacuum-insulated catalytic converter with phase change material was used to store exhaust heat and resist heat loss during times of dwell/soak.

In previous SAE papers, the initial development and testing of a vacuum-insulated catalytic converter was presented. This paper provides an update of the converter development and an analysis of potential off-cycle emissions savings. Hot vibration, cool-down, and 1975 Federal Test Procedure (FTP-75) emissions test results are provided to demonstrate the effectiveness of design improvements in greatly increasing durability while retaining performance. Using standard drive cycles and “real-world” driving statistics with a vehicle simulator (ADVISOR©), catalyst temperature and vehicle exhaust emissions of a sport utility vehicle (SUV) were predicted for 16 days of driving (107 trips, 770 total miles). Compared to the baseline vehicle with a conventional catalytic converter, the SUV with a vacuum-insulated converter produced 66% less non-methane hydrocarbon (NMHC), 65% less carbon monoxide (CO), and 60% less oxides of nitrogen (NOx).