Cylinder Air/Fuel Ratio Estimation Using Net Heat Release Data

Tunestål, Per; Hedrick, J. Karl

doi:10.1016/s1474-6670(17)34403-8

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…The crankshaft speed fluctuations and heat release analysis of the cylinder pressure can be used to develop these observers. 34,35 To implement the proposed online control scheme, a simple yet sufficiently accurate coldstart engine model is needed to reduce the computational efforts. A control-oriented coldstart model which has been developed through experimentation at the University of California, Berkeley's engine test facility will be a good choice.…”

Section: Proposed Model-based Coldstart Control Scheme For Online Appmentioning

confidence: 99%

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Online optimization of automotive engine coldstart hydrocarbon emissions control at idle conditions

Azad

2015

Proceedings of the Institution of Mechanical Engineers, Part I:

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In this work, we propose a model-based scheme for the online optimization of coldstart hydrocarbon emission control strategy of an automotive spark-ignited engine during its idle operating conditions. First, the existing model-based control schemes to reduce the coldstart emissions are reviewed and classified. Then, the proposed scheme and the related control-oriented engine model validated by experimental data are introduced. At the heart of the suggested scheme, there is a new optimal control problem formulation for the coldstart that can be solved rapidly using the Pontryagin's minimum principle. This formulation is based on a redefined objective function with weighted terms for the coldstart key variables, that is, the engine-out hydrocarbon emission and the exhaust gas temperature. The weighting numbers for these dominant factors in the redefined objective function are tuned such that the optimum solution becomes close to the minimum of the cumulative tailpipe hydrocarbon emissions. The use of the redefined objective function reduces significantly the computational efforts, resulting in an order of magnitude faster convergence rate than solving the original coldstart hydrocarbon emission minimization problem with a complex form. This important property is demonstrated with some simulation results based on the above-mentioned engine model. This feature makes the new formulation a good fit to the proposed scheme, where measured or estimated state variables of the engine model can be fed back to the control unit to re-calculate online the input profiles, such as the spark timing and the air/fuel ratio. Through online modification of the pre-determined input trajectories obtained from off-line calculations, the control performance degradation in practice due to the plant/model mismatch, which is equivalent to a significant increase of the tailpipe hydrocarbon emissions, can be reduced considerably.

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Section: Proposed Model-based Coldstart Control Scheme For Online Appmentioning

confidence: 99%

“…The crankshaft speed fluctuations and heat release analysis of the cylinder pressure can be used to develop these observers. 34,35…”

Section: Proposed Model-based Coldstart Control Scheme For Online Appmentioning

confidence: 99%

Online optimization of automotive engine coldstart hydrocarbon emissions control at idle conditions

Azad

2015

Proceedings of the Institution of Mechanical Engineers, Part I:

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“…It is noteworthy that although the stability of combustion in cylinders also affects measured FAR, limited by mechanical structure of engine and measurement technology, it is difficult to measure FAR of each cylinder and distinguish the influence of combustion in practice. Although some researches show that there is a chance to estimate cylinder FAR by adding in‐cylinder pressure sensor or ion current sensor [26–28], their precisions are relatively low and should be further improved when applying for FAR control. Therefore the widely used mean value model is employed here for FAR control, and the research is developed based on the assumption that combustion in expansion stroke has been well controlled so that either gasoline or oxygen in cylinder can be burned out all the time and the influence of combustion to FAR is ignored.…”

Section: Far Model Descriptionmentioning

confidence: 99%

Fuel–air ratio control for a spark ignition engine using gain‐scheduled delay‐dependent approach

Yin

Liu

2015

IET Control Theory & Applications

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Determining Model Accuracy Requirements for Automotive Engine Coldstart Hydrocarbon Emissions Control

Azad

Sanketi

Hedrick

2012

Journal of Dynamic Systems, Measurement, and Control

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In this work, a systematic method is introduced to determine the required accuracy of an automotive engine model used for real-time optimal control of coldstart hydrocarbon (HC) emissions. The engine model structure and development are briefly explained and the model predictions versus experimental results are presented. The control design problem is represented with a dynamic optimization formulation on the basis of the engine model and solved using the Pontryagin’s minimum principle (PMP). To relate the level of plant/model mismatch and the control performance degradation in practice, a sensitivity analysis using a computationally efficient method is employed. In this way, the sensitivities or the effects of small parameter variations on the optimal solution, which is the minimum of cumulative tailpipe HC emissions over the coldstart period, are calculated. There is a good agreement between the sensitivity analysis results and the experimental data. The sensitivities indicate the directions of the subsequent parameter estimation and model improvement tasks to enhance the control-relevant accuracy, and thus, the control performance. Furthermore, they provide some insights to simplify the engine model, which is critical for real-time implementation of the coldstart optimal control system.

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Cylinder Air/Fuel Ratio Estimation Using Net Heat Release Data

Cited by 5 publications

References 8 publications

Online optimization of automotive engine coldstart hydrocarbon emissions control at idle conditions

Online optimization of automotive engine coldstart hydrocarbon emissions control at idle conditions

Fuel–air ratio control for a spark ignition engine using gain‐scheduled delay‐dependent approach

Determining Model Accuracy Requirements for Automotive Engine Coldstart Hydrocarbon Emissions Control

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