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Parameterized Diesel Engine Combustion Modeling for Torque Based Combustion Property Estimation

Chalmers University of Technology-Mikael Thor, Bo Egardt, Tomas McKelvey, Ingemar Andersson
Published 2012-04-16 by SAE International in United States
Combustion model structures based on Vibe functions are outlined and investigated in this work. The focus of the study is the use of such model structures for estimation of diesel combustion properties by reconstructing in-cylinder pressure from measurements of crankshaft torque. Investigated combustion properties include the start and phasing of the combustion as well as maximum values of the in-cylinder pressure and its derivative. The accuracy associated with the proposed estimation method is evaluated using ideal torque data, i.e. torque calculated from in-cylinder pressure, that is generated using both simulations and experiments. The results indicate that the uncertainty associated with the estimation of a selected combustion property tends to increase if that property is located close to TDC, where the signal-to-noise ratio is low for a torque signal. The results also show that the ideal torque based estimation of combustion phasing and maximum in-cylinder pressure generally is very accurate while the estimation of start of combustion and the maximum in-cylinder pressure derivative suffers more from disturbances and model imperfections.
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PHEV Energy Management: A Comparison of Two Levels of Trip Information

Chalmers University of Technology-Mitra Pourabdollah, Viktor Larsson, Lars johannesson, Bo Egardt
Published 2012-04-16 by SAE International in United States
Plug-in hybrid electric vehicles (PHEVs) have rechargeable energy storage which can be used to run the vehicle on shorter range on electricity from the grid. In the absence of a priori information about the trip, a straightforward strategy is to first deplete the battery down to a minimum level and then keep the state of charge (SoC) around this level. However, largely due to the battery losses, the overall fuel economy can be improved if the battery is discharged gradually. This requires some a priori knowledge about the trip.This paper investigates the tradeoff between improved fuel economy and the need for a priori information. This investigation is done using a variant of telemetry equivalent consumption minimization strategy (T-ECMS) which is modified to be used for a PHEV. To implement this strategy, several parameters need to be tuned based on an assumption of the future trip. By studying two different levels of details, the tradeoff between fuel economy and a priori information is evaluated. It is shown that the proposed strategy improves the fuel economy considerably…
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SI Engine Spark Advance Control Using Torque Sensors

Chalmers University of Technology-Stefan Larsson, Bo Egardt
  • Technical Paper
  • 2004-35-0103
Published 2004-04-19 by University of Salerno in Italy
A controller concept regarding how a torque sensor can be utilized for self-optimizing efficiency of an SI engine is introduced. The first steps toward a controller for spark advance control is presented which assumes perfect estimation of the peak pressure position (PPP) in each cylinder. The estimation procedure is presented in accompanying work. The resulting spark advance controller is constructed based on a PI controller. Its stability is analyzed; the controller parameters are chosen based on a robustness measure and the final design is simulated with and without noise.

Estimation of Backlash in Automotive Powertrains~An Experimental Validation

Chalmers University of Technology-Bo Egardt
Jönköping Univ.-Adam Lagerberg
  • Technical Paper
  • 2004-35-0023
Published 2004-04-19 by University of Salerno in Italy
In automotive powertrains, backlash imposes well-known limitations on the quality of control and hence the driveability. In order to increase the controller performance, knowledge of the backlash properties (size and current position) is needed. In previous papers, nonlinear estimators for backlash size and position are described, based on Kalman filtering theory. The size and position estimators are combined, and the result is an estimate of the state of the backlash. In this paper, experimental results from vehicle tests show that the estimates are of high quality, and hence useful for improving backlash compensation functions in the powertrain control system.
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Backstepping Control with Integral Action Applied to Air-to-Fuel Ratio Control for a Turbocharged Diesel Engine

Chalmers University of Technology-Jonas Fredriksson, Bo Egardt
Published 2002-03-04 by SAE International in United States
The problem of controlling the air-to-fuel ratio of a diesel engine by utilizing the potential of a variable geometry turbine is addressed in this paper. The proposed control law is derived from a backstepping procedure and ensures a local optimal performance close to the operating point. Accurate air-to-fuel ratio is important for emission reduction in diesel engines, therefore is integral action included in the control law to mitigate the effects of constant disturbance inputs or parameter (model) errors. The performance is illustrated by an analytical example.
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