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This paper presents a novel approach in real-time engine modeling. Unlike standard practices, which involve system level modeling, the presented methodology is a hybrid physical/system domain solution. Specifically, for each subsystem that the engine is divided into, a physical, map-based, or combination physical/map-based solution is chosen depending on the available computational power and the desired model detail. The resulting semi-physical engine models are suitable for real-time applications, such as Hardware-In-Loop (HiL) simulations, and, at the same time, re-usable to a large extent when model updates are required. In addition, since the proposed methodology allows for variable level of detail -from models as simple as pure map-based look-ups for torque, airflow, and exhaust temperature, all the way to models capable of predicting crank angle resolved cylinder pressure- it provides natural adjustability to the ongoing growth of computer power.

As engines advance toward greater efficiency and lower emissions, there is increasing need for accurate real-time residual models for engine control. Both the formulation of real-time-capable models and the development of methods for measuring or estimating residuals during engine calibration have been difficult and longstanding problems. This paper describes development of a low-cost, easy-to-use tool for on-line residual estimation in all cylinders of an IC engine. The basic method, hardware required, and software structure are described. The residual estimation tool was applied to estimate residuals over the operating map in all cylinders of a six-cylinder direct-injection SI engine equipped with dual-independent phasers. The data was used to calibrate a real-time residual model integrated into the engine management system. Validation data confirming accuracy of the model are presented.

The V-Cycle is a well accepted and commonly implemented process model for systems engineering. The concept phase is represented by the upper-left portion of the V, in which very high level system simulations are the predominant modeling activity. Traveling down the V toward the vertex, sub-system level and component level simulations are employed as one enters the development phase. Finally, the test and validation phase is completed, and is represented by the right side of the V. Simulation tools have historically been used throughout some phases of the V-cycle, and with the ever increasing computing power, and the increasingly accurate and predictive simulation tools available to the engineer, today it is common that simulation is used in every phase of the cycle, from concept straight through the test and validation phases.

An increasing demand for reducing cost and time effort of the design process via improved CAE (Computer-Aided Engineer) tools and methods has characterized the automotive industry over the past two decades. One of the main challenges involves the effective simulation of a vehicle’s propulsion system dealing with different physical domains: several examples have been proposed in the literature mainly based on co-simulation approach which involves a specific tool for each propulsion system part modeling. Nevertheless, these solutions are not fully suitable and effective to perform statistical analysis including all physical parameters. In this respect, this paper presents the definition and implementation of a new simulation methodology applied to a propulsion subsystem.