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Fuel Injection Control Systems that Improve Three Way Catalyst Conversion Efficiency
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Abstract
A fuel control method to reduce the harmful exhaust gas from SI engines is proposed. As is well known, both the amplitude and the frequency of the limit cycle in a conventional air-fuel ratio control system are determined uniquely by parameters in the system. And this limits our making full use of the oxygen storage effect of TWC.
A simple model of TWC reaction revealed the relationship between maximum conversion efficiency and both the amplitude and the frequency in a air fuel control system. It also revealed that TWC conversion efficiency attained to maximum levels when both the amplitude and the frequency of the limit cycle are selected so as to make full use of the oxygen storage effect of TWC. In order to achieve this, it is necessary to vary both the amplitude and the frequency arbitrarily. Superimposing a modulation signal ( artificial modulation ) with a higher frequency than the conventional one on the fuel control signal is able to to vary the amplitude of the limit cycle independently of the frequency. This means artificial modulation can always operate TWC at its maximum conversion efficiency. A remarkable improvement by our artificial modulation was confirmed in both the engine dynamometer test and US Federal Test.
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Citation
Katashiba, H., Nishida, M., Washino, S., Takahashi, A. et al., "Fuel Injection Control Systems that Improve Three Way Catalyst Conversion Efficiency," SAE Technical Paper 910390, 1991, https://doi.org/10.4271/910390.Also In
References
- Falk, C.D. Moony, J.J. “Three-Way Conversion Catalysts Effect of Closed-Loop Feed-Back Control and Other Parameters on Catalyst Efficiency” SAE paper 800462 1980
- Funabiki, M. Yamada, T. “A Study on Three Way Catalyst Thermal Deactivation and Improvement” SAE paper 881684 1988
- Matsunaga, S. Yokota, K. Muraki, H. Fujitani, Y. “Improvement of Engine Emissions Over Three-Way Catalyst by the Periodic Operations” SAE paper 872098 1987
- Yokota, K. Muraki, H. Fujitani, Y. “Rh-Free Three-Way Catalysts for Automotive Exhaust Control” SAE paper 850129 1985
- Meitzler, A.H. “Application of Exhaust-Gas-Oxygen Sensors to the Study of Storage Effects in Automotive Three-Way Catalysts” SAE paper 80019 1980
- Heck, R.H. Wei, J. Katzer, J.R. “Mathematical Modeling of Monolithic Catalysts” AIChE J. 22 477 1976