Development and Validation of an Oxygen Storage Model for Three Way Catalysts

Author(s):  
Touraj Khossusi ◽  
Roy Douglas ◽  
Geoffrey Mccullough
2007 ◽  
Author(s):  
Gang Guo ◽  
Michael Shane ◽  
Paul Laing ◽  
Trescott E. Jensen
Keyword(s):  

Author(s):  
Abdullah-al Mamun ◽  
Qilun Zhu ◽  
Mark Hoffman ◽  
Simona Onori

The Current practice of air-fuel ratio control relies on empirical models and traditional PID controllers, which require extensive calibration to maintain the post-catalyst air-fuel ratio close to stoichiometry. In contrast, this work utilizes a physics-based Three-Way Catalyst (TWC) model to develop a model predictive control (MPC) strategy for air-fuel ratio control based on internal TWC oxygen storage dynamics. In this paper, parameters of the physics-based temperature and oxygen storage models of the TWC are identified using vehicle test data for a catalyst aged to 150,000 miles. A linearized oxygen storage model is then developed from the identified nonlinear model, which is shown via simulation to follow the nonlinear model with minimal error during nominal operation. This motivates the development of a Linear MPC (LMPC) framework using the linearized TWC oxygen storage model, reducing the requisite computational effort relative to a nonlinear MPC strategy. In this work, the LMPC utilizing a linearized physics-based TWC model is proven suitable for tracking a desired oxygen storage level by controlling the commanded engine air-fuel ratio, which is also a novel contribution. The offline simulation results show successful tracking performance of the developed LMPC framework.


2007 ◽  
Vol 177 (4S) ◽  
pp. 7-7
Author(s):  
Brent K. Hollenbeck ◽  
J. Stuart Wolf ◽  
Rodney L. Dunn ◽  
Martin G. Sanda ◽  
David P. Wood ◽  
...  

2018 ◽  
Vol 34 (3) ◽  
pp. 193-205 ◽  
Author(s):  
Julia Steinbach ◽  
Heidrun Stoeger

Abstract. We describe the development and validation of an instrument for measuring the affective component of primary school teachers’ attitudes towards self-regulated learning. The questionnaire assesses the affective component towards those cognitive and metacognitive strategies that are especially effective in primary school. In a first study (n = 230), the factor structure was verified via an exploratory factor analysis. A confirmatory factor analysis with data from a second study (n = 400) indicated that the theoretical factor structure is appropriate. A comparison with four alternative models identified the theoretically derived factor structure as the most appropriate. Concurrent validity was demonstrated by correlations with a scale that measures the degree to which teachers create learning environments that enable students to self-regulate their learning. Retrospective validity was demonstrated by correlations with a scale that measures teachers’ experiences with self-regulated learning. In a third study (n = 47), the scale’s concurrent validity was tested with scales measuring teachers’ evaluation of the desirability of different aspects of self-regulated learning in class. Additionally, predictive validity was demonstrated via a binary logistic regression, with teachers attitudes as predictor on their registration for a workshop on self-regulated learning and their willingness to implement a seven-week training program on self-regulated learning.


2020 ◽  
Vol 36 (5) ◽  
pp. 852-863 ◽  
Author(s):  
George Gunnesch-Luca ◽  
Klaus Moser

Abstract. The current paper presents the development and validation of a unit-level Organizational Citizenship Behavior (OCB) scale based on the Referent-Shift Consensus Model (RSCM). In Study 1, with 124 individuals measured twice, both an Exploratory Factor Analysis (EFA) and a Confirmatory Factor Analysis (CFA) established and confirmed a five-factor solution (helping behavior, sportsmanship, loyalty, civic virtue, and conscientiousness). Test–retest reliabilities at a 2-month interval were high (between .59 and .79 for the subscales, .83 for the total scale). In Study 2, unit-level OCB was analyzed in a sample of 129 work teams. Both Interrater Reliability (IRR) measures and Interrater Agreement (IRA) values provided support for RSCM requirements. Finally, unit-level OCB was associated with group task interdependence and was more predictable (by job satisfaction and integrity of the supervisor) than individual-level OCB in previous research.


2008 ◽  
Vol 93 (2) ◽  
pp. 250-267 ◽  
Author(s):  
Troy V. Mumford ◽  
Chad H. Van Iddekinge ◽  
Frederick P. Morgeson ◽  
Michael A. Campion

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