Estimation of Engine Torque from a First Law Based Regression Model

Brahma, Indranil; Sharp, Mike C.; Frazier, Tim R.

doi:10.4271/2008-01-1014

Cited by 16 publications

(11 citation statements)

References 15 publications

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“…The oxygen mole fraction was calculated from ECM estimates of EGR fraction and charge flow, and resulted in a 10 per cent improvement in PM predictions, even though the ECM estimates have been shown to be inaccurate in the companion work [1]. This is consistent with previous conclusions reached by Brahma et al that empirical models benefit from using more fundamental model parameters, even if they themselves are derived from higher level parameters [18]. As will be described in the next subsections, this simple model outperformed more complex empirical approaches and predicted cumulative cycle NO x and PM within 3 per cent and 15 per cent, respectively, see Tables 4 and 5 later on.…”

Section: Modelling Methods and Model Formsupporting

confidence: 72%

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Development of a model-based transient calibration process for diesel engine electronic control module tables – Part 2: modelling and optimization

Brahma

Chi

2011

International Journal of Engine Research

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This is the second part of a study investigating a model-based transient calibration process for diesel engines. The first part addressed the data requirements and data processing required for empirical transient emission and torque models. The current work focuses on modelling and optimization. The unexpected result of this investigation is that when trained on transient data, simple regression models perform better than more powerful methods such as neural networks or localized regression. This result has been attributed to extrapolation over data that have estimated rather than measured transient air-handling parameters. The challenges of detecting and preventing extrapolation using statistical methods that work well with steady-state data have been explained. The concept of constraining the distribution of statistical leverage relative to the distribution of the starting solution to prevent extrapolation during the optimization process has been proposed and demonstrated. Separate from the issue of extrapolation is preventing the search from being quasi-static. Second-order linear dynamic constraint models have been proposed to prevent the search from returning solutions that are feasible if each point were run at steady state, but which are unrealistic in a transient sense. Dynamic constraint models translate commanded parameters to actually achieved parameters that then feed into the transient emission and torque models. Combined model inaccuracies have been used to adjust the optimized solutions. To frame the optimization problem within reasonable dimensionality, the coefficients of commanded surfaces that approximate engine tables are adjusted during search iterations, each of which involves simulating the entire transient cycle. The resulting strategy, different from the corresponding manual calibration strategy and resulting in lower emissions and efficiency, is intended to improve rather than replace the manual calibration process.

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Section: Modelling Methods and Model Formsupporting

confidence: 72%

“…This is consistent with previous conclusions reached by Brahma et al . that empirical models benefit from using more fundamental model parameters, even if they themselves are derived from higher level parameters [18].…”

Section: Transient Emission and Torque Modelsmentioning

confidence: 99%

Development of a model-based transient calibration process for diesel engine electronic control module tables – Part 2: modelling and optimization

Brahma

Chi

2011

International Journal of Engine Research

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“…Moreover, because the mean value model is constructed based on semi-transient state characteristics, it is difficult to predict transient torque precisely [29]. Thermodynamic laws have also been used to estimate the engine torque [29,30]. It is reported in [29] that using Wiebe function can give good estimation in both slow and fast engine operation.…”

Section: Simulation Results With Switched Observer Gainmentioning

confidence: 98%

Observer-based clutch disengagement control during gear shift process of automated manual transmission

Gao

Lei

et al. 2010

Vehicle System Dynamics

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A clutch disengagement strategy is proposed for the shift control of automated manual transmissions. The control strategy is based on a drive shaft torque observer. With the estimated drive shaft torque, the clutch can be disengaged as fast as possible without large driveline oscillations, which contributes to the reduction of total shift time and shift shock. The proposed control strategy is tested on a complete powertrain simulation model. It is verified that the system is robust to the variations of driving conditions, such as vehicle mass and road grade. It is also demonstrated that the revised system with switched gain can provide satisfactory performance even under large estimation error of the engine torque.

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“…Accumulations of the sensors' measurement errors, modeling inaccuracies from model structures and calibrations, aging and drift factors of engines as well as cylinder-to-cylinder combustion variations have prevented developers from achieving optimum solution [4].…”

Section: Introductionmentioning

confidence: 99%

“…This explains the significant amount of research activity to enhance torque estimation and measurement [4,[6][7][8][9][10]. Without reliable direct torque measurement, robust torque feedback control is challenging especially during transients.…”

Section: Introductionmentioning

confidence: 99%

Direct Torque Feedback for Accurate Engine Torque Delivery and Improved Powertrain Performance

Alkeilani

Wang

Ying

2016

Journal of Engineering for Gas Turbines and Power

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At the present time, both control and estimation accuracies of engine torque are causes for underachieving optimal drivability and performance in today's production vehicles. The major focus in this area has been to enhance torque estimation and control accuracies using existing open loop torque control and estimation structures. Such an approach does not guarantee optimum torque tracking accuracy and optimum estimation accuracy due to air flow and efficiency estimation errors. Furthermore, current approach overlooks the fast torque path tracking which does not have any related feedback. Recently, explicit torque feedback control has been proposed in the literature using either estimated or measured torques as feedback to control the torque using the slow torque path only. We propose the usage of a surface acoustic wave (SAW) torque sensor to measure the engine brake torque and feedback the signal to control the torque using both the fast and slow torque paths utilizing an inner–outer loop control structure. The fast torque path feedback is coordinated with the slow torque path by a novel method using the potential torque that is adapted to the sensor reading. The torque sensor signal enables a fast and explicit torque feedback control that can correct torque estimation errors and improve drivability, emission control, and fuel economy. Control oriented engine models for the 3.6L engine are developed. Computer simulations are performed to investigate the advantages and limitations of the proposed control strategy versus the existing strategies. The findings include an improvement of 14% in gain margin and 60% in phase margin when the torque feedback is applied to the cruise control torque request at the simulated operating point. This study demonstrates that the direct torque feedback is a powerful technology with promising results for improved powertrain performance and fuel economy.

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Estimation of Engine Torque from a First Law Based Regression Model

Cited by 16 publications

References 15 publications

Development of a model-based transient calibration process for diesel engine electronic control module tables – Part 2: modelling and optimization

Development of a model-based transient calibration process for diesel engine electronic control module tables – Part 2: modelling and optimization

Observer-based clutch disengagement control during gear shift process of automated manual transmission

Direct Torque Feedback for Accurate Engine Torque Delivery and Improved Powertrain Performance

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