Empirical Modeling of Transient Emissions and Transient Response for Transient Optimization

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

doi:10.4271/2009-01-1508

Cited by 27 publications

(28 citation statements)

References 37 publications

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“…A Transient Cycle is usually characterized by long duration (up to 30 min) consisting of both speed and load changes under varying operating schedules simulating real driving conditions. During the last decades, the modeling and the experimental investigation of the thermodynamic and gas dynamic processes in diesel engines has intensively supported the study of engine transient operation [3][4][5][6][7][8][9][10]. However, the vital issue of exhaust emissions as well as the overall engine and vehicle performance during a Transient Cycle -although of primary concern to engine manufacturers -has not been investigated adequately but rather segmentally owing to the following two major issues:…”

Section: Introductionmentioning

confidence: 99%

Study of diesel engine performance and emissions during a Transient Cycle applying an engine mapping-based methodology

Giakoumis

Alafouzos

2010

Applied Energy

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Section: Introductionmentioning

confidence: 99%

Study of diesel engine performance and emissions during a Transient Cycle applying an engine mapping-based methodology

Giakoumis

Alafouzos

2010

Applied Energy

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“…[1][2][3] It was noticed that many kinds of empirical model could 'fit' the PM data but model predictions for test data generated from any transient calibration which are significantly different from that used to generate the training data were poor, i.e. models were calibration dependent.…”

Section: Introductionmentioning

confidence: 99%

A decision-tree-based approach to smoke spike detection in a heavy-duty diesel engine

Brahma

2012

Proceedings of the Institution of Mechanical Engineers, Part D:

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Smoke spikes occurring during transient engine operation have detrimental health effects and increase fuel consumption by requiring more frequent regeneration of the diesel particulate filter. This paper proposes a decision tree approach to real-time detection of smoke spikes for control and on-board diagnostics purposes. A contemporary, electronically controlled heavy-duty diesel engine was used to investigate the deficiencies of smoke control based on the fuel-to-oxygenratio limit. With the aid of transient and steady state data analysis and empirical as well as dimensional modeling, it was shown that the fuel-to-oxygen ratio was not estimated correctly during the turbocharger lag period. This inaccuracy was attributed to the large manifold pressure ratios and low exhaust gas recirculation flows recorded during the turbocharger lag period, which meant that engine control module correlations for the exhaust gas recirculation flow and the volumetric efficiency had to be extrapolated. The engine control module correlations were based on steady state data and it was shown that, unless the turbocharger efficiency is artificially reduced, the large manifold pressure ratios observed during the turbocharger lag period cannot be achieved at steady state. Additionally, the cylinder-to-cylinder variation during this period were shown to be sufficiently significant to make the average fuel-to-oxygen ratio a poor predictor of the transient smoke emissions. The steady state data also showed higher smoke emissions with higher exhaust gas recirculation fractions at constant fuel-to-oxygen-ratio levels. This suggests that, even if the fuel-to-oxygen ratios were to be estimated accurately for each cylinder, they would still be ineffective as smoke limiters. A decision tree trained on snap throttle data and pruned with engineering knowledge was able to use the inaccurate engine control module estimates of the fuel-to-oxygen ratio together with information on the engine control module estimate of the exhaust gas recirculation fraction, the engine speed, and the manifold pressure ratio to predict 94% of all spikes occurring over the Federal Test Procedure cycle. The advantages of this non-parametric approach over other commonly used parametric empirical methods such as regression were described. An application of accurate smoke spike detection in which the injection pressure is increased at points with a high opacity to reduce the cumulative particulate matter emissions substantially with a minimum increase in the cumulative nitrogrn oxide emissions was illustrated with dimensional and empirical modeling.

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“…This optimisation can be carried out directly on the engine [1], or mathematical models may be used in place of the physical engine [2], [3]. An overview on modelling approaches and the corresponding data acquisition can be found in [4]. Often, statistical tools are applied to assist the engineer in deriving the control maps, see e.g.…”

Section: Introductionmentioning

confidence: 99%

From static to dynamic optimisation of Diesel-engine control

Aspriona

Chinellato²,

Onder

et al. 2013

52nd IEEE Conference on Decision and Control

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A framework for the numerical solution of optimal control problems is modified such that an arbitrary subset of the state variables can be treated as quasi-stationary quantities. This framework is used to reduce the number of state variables of a turbocharged Diesel engine by sequentially omitting the pressure dynamics, the turbocharger inertia, and the thermal dynamics. By comparison to a dynamic simulation using the resulting optimal control inputs, the effects of neglecting these dynamics are assessed. A physics-based combustion model is used in combination with an extended mean-value model for the air path, and a segment of 295s of the World-Harmonized Transient Cycle is considered. The methodology bridges the gap between stationary engine calibration and dynamic optimisation. It reveals which control signals can be represented by lookup maps. For the remaining dynamic control paths, optimal feedforward maps are obtained. Furthermore, the results indicate suitable feedback variables and provide optimal reference maps.

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Empirical Modeling of Transient Emissions and Transient Response for Transient Optimization

Cited by 27 publications

References 37 publications

Study of diesel engine performance and emissions during a Transient Cycle applying an engine mapping-based methodology

Study of diesel engine performance and emissions during a Transient Cycle applying an engine mapping-based methodology

A decision-tree-based approach to smoke spike detection in a heavy-duty diesel engine

From static to dynamic optimisation of Diesel-engine control

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