Scalale Modeling Depths for realtime engine simulation applied fro model based calibration

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Controls, Measurement & Calibration Congress 2014, Brazil

Scalable Modeling Depths for Realtime Engine Simulation Applied for Model Based Calibration Johann KRAMMER AVL List GmbH, Hans-List-Platz 1, 8020 Graz, Austria

ABSTRACT Demands for more functions in an automobile are continuously growing and thereby its complexity. Technologies like Hardware-in-Loop simulation based on physical modeling of the engine with all its subsystems can be used to the calibration process. This paper gives an overview on available engine modeling depths, from purely data driven empirical models to physics based crank angle resolved models to be applied from the concept phase up to testing. Compared to empirical models physical models are more accurate and are significantly more robust when operated outside “default” operating conditions. It often can be observed that in the concept and calibration phase models are developed independent of each other. This inconsistency typically sums up in double work for base data collection, model design and model tuning. With the goal of frontloading and moving the calibration work earlier in the development process a horizontal consistency of the models is becoming even more important.

INTRODUCTION Demands for more functions in an automobile are continuously growing and at the same time complexity of the powertrain. Stringent economic and environmental constrains are challenging the development of modern IC engines. Simulation supports the engineer to manage these new functions and variants and it’s subsystem interactions with a reasonable effort to fulfill the consumers request for low fuel consumption and fun to drive. System level simulations are required to incorporate different domains like engine, drive train, cooling, exhaust aftertreatment and engine control, in a multi-physical manner. In the early concept phase, when lacking measurements, models need to rely on first order principles and empirical approaches with a sound knowledge basis of model parameters. In the late control design and calibration phase real-time capable models are mandatory

REAL-TIME ENGINE MODELS This section aims at comprising a compact description of the different approaches developed in the framework of AVL CRUISE M Engine. Following terms are used to specify the gas path consideration: •

1D Gas Dynamics: Pressure waves and it’s propagation in Crank-Angel resolution

0D Gas Dynamics: Pressure waves in Crank-Angel resolution

0D Mean Value Gas Path: Cycle average pressure (no pressure waves)

In) 1D GAS-DYNAMICS IN CRANK-ANGLE RESOLUTION In state-of-the-art engine simulators, the engine models are flexibly assembled out of base elements such as cylinders, pipes, turbochargers, catalytic converters, and so on. The solution of the 1D Euler equations (balances for mass,


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