Model-based diesel Engine Management System optimization for transient engine operation

Grahn, Markus; Johansson, Krister; McKelvey, Tomas

doi:10.1016/j.conengprac.2014.04.005

Cited by 22 publications

(4 citation statements)

References 23 publications

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“…These systems have many degrees of freedom, and many settings that can be calibrated. A sophisticated global optimization procedure that accounts for all systems' settings is, in practice, not (yet) possible [29], [30]. Instead, some systems' settings are calibrated manually at an early design stage, and possibly in conjunction with the hardware design, such as design of pistons, cylinder head, and physical location of injectors.…”

Section: Engine Calibration Procedures For Conventional Vehiclesmentioning

confidence: 99%

Automated Engine Calibration of Hybrid Electric Vehicles

Murgovski

Grahn

Johannesson

et al. 2015

IEEE Trans. Contr. Syst. Technol.

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We present a method for automated engine calibration, by optimizing engine management settings and power-split control of a hybrid electric vehicle. The problem, which concerns minimization of fuel consumption under a NOX constraint, is formulated as an optimal control problem. By applying Pontryagin's maximum principle, this study shows that the problem is separable in space. In the case where the limits of battery state of charge are not activated, we show that the optimization problem is also separable in time. The optimal solution is obtained by iteratively solving the power-split control problem using dynamic programming or the Equivalent Consumption Minimization Strategy. In addition, we present a computationally efficient suboptimal solution, which aims at reducing the number of power-split optimizations required. An example is provided concerning optimization of engine management settings and power-split control of a parallel hybrid electric vehicle.

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Section: Engine Calibration Procedures For Conventional Vehiclesmentioning

confidence: 99%

Automated Engine Calibration of Hybrid Electric Vehicles

Murgovski

Grahn

Johannesson

et al. 2015

IEEE Trans. Contr. Syst. Technol.

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“…A fuel consumption decrease potential of up to 0.7% compared to using an EMS optimization strategy based only on steadystate engine operation was demonstrated. The method was further evaluated in Grahn et al (2013b) where a complete diesel engine vehicle system simulation model driving according to the New European Driving Cycle (NEDC) was used, and a fuel consumption decrease of 0.56% was demonstrated. A downside with the approach in Grahn et al (2013b) is that the set point function maps used linear interpolation maps with a three-dimensional grid map for the oxygen fraction set point, and a fourdimensional grid-map for the injection timing.…”

Section: Introductionmentioning

confidence: 99%

A Transient Diesel EMS Strategy for Online Implementation

Grahn

Johansson

McKelvey

2014

IFAC Proceedings Volumes

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A recently developed strategy for diesel engine management systems is modified to reduce the implementation complexity. The strategy calculates set points for engine management system controllable quantities with an aim to minimize fuel consumption for a given engine speed and requested torque profile, while keeping accumulated emissions below given limits. The strategy is based on the methodology for steady-state engine operation, but extended to handle transient effects in the engine caused by dynamics in the air system. The strategy leads to the parametrization of mappings with two, three and four input dimensions respectively. In this paper, a modification of the strategy is proposed such that the memory demanding multidimensional mappings can be approximated in an engine management system using only two-dimensional grid maps. The modified strategy has been evaluated using a complete diesel engine vehicle system model simulating the NEDC driving cycle. The performance of the modified strategy has been compared with the original performance of the strategy. It is demonstrated that the modification of the strategy has very little impact on resulting performance of a vehicle but requires considerably less memory for implementation.

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“…One method is implementing the optimal controls as transient compensation maps together with the normal stationary calibration. This approach is advocated in [4,32,47]. Another approach along the same lines, i.e.…”

Section: Optimal Control Of Diesel Enginesmentioning

confidence: 99%

Optimal Control of Electrified Powertrains

Sivertsson

2015

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The cover: Front: Formulation and solution of an optimal control problem, coincidentally the benchmark problem in Paper 6. Back: Positive and not so positive exit messages from the solvers used in the dissertation. Typeset with L A T E X 2εPrinted by LiU-Tryck, Linköping, Sweden 2015 i Abstract Vehicle powertrain electrification, i.e. combining the internal combustion engine (ICE) with an electric motor (EM), is a potential way of meeting the increased demands for efficient and low emission transportation, at a price of increased powertrain complexity since more degrees of freedom (DoF) have been introduced. Optimal control is used in a series of studies of how to best exploit the additional DoFs.In a diesel-electric powertrain the absence of a secondary energy storage and mechanical connection between the ICE and the wheels means that all electricity used by the EMs needs to be produced simultaneously by the ICE, whose rotational speed is a DoF. This in combination with the relatively slow dynamics of the turbocharger in the ICE puts high requirements on good transient control.In optimal control studies, accurate models with good extrapolation properties are needed. For this aim two nonlinear physics based models are developed and made available that fulfill these requirements, these are also smooth in the region of interest, to enable gradient based optimization techniques. Using optimal control and one of the developed models, the turbocharger dynamics are shown to have a strong impact on how to control the powertrain and neglecting these can lead to erroneous estimates both in the response of the powertrain as well as how the powertrain should be controlled. Also the objective, whether time or fuel is to be minimized, influences the engine speed-torque path to be used, even though it is shown that the time optimal solution is almost fuel optimal. To increase the freedom of the powertrain control, a small energy storage can be added to assist in the transients. This is shown to be especially useful to decrease the response time of the powertrain, but the manner it is used, depends on the time horizon of the optimal control problem.The resulting optimal control solutions are for certain cases oscillatory when stationary controls would have been expected. This is shown to be neither an artifact of the discretization used nor a result of the modeling assumptions used. Instead it is for the formulated problems actually optimal to use periodic control in certain stationary operating points. Measurements show that the pumping torque is different depending on whether the controls are periodic or constant despite the same average value. Whether this is beneficial or not depends on the operating point and control frequency, but can be predicted using optimal periodic control theory.In hybrid electric vehicles (HEV) the size of the energy storage reduces the impact of poor transient control, since the battery can compensate for the slower dynamics of the ICE. For HEVs the problem instead is how and when to use the b...

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Model-based diesel Engine Management System optimization for transient engine operation

Cited by 22 publications

References 23 publications

Automated Engine Calibration of Hybrid Electric Vehicles

Automated Engine Calibration of Hybrid Electric Vehicles

A Transient Diesel EMS Strategy for Online Implementation

Optimal Control of Electrified Powertrains

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