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Common rail fuel injection is the latest breakthrough in diesel engine technology. For research, development and quality control of the used electronic control units (ECU's), hardware-in-the-loop-simulation (HIL) is a useful tool for test and verification. The paper describes a high resolution real-time model of pump, rail, control valve and injectors which results in a reliable approximation of the dynamic characteristic of pressure and mass flow of the fuel. In respect to computing time and system resources this model is combined with a steady state model of a Diesel engine. It describes mainly the effects of the input variables start of injection and injection time on the engine torque at the operating point of the engine, defined by its speed and intake manifold pressure. The theoretical deduction will be completed by simulation results of the transient behavior of a Common Rail engine which are simulated by the real-time simulator CARTS(1) (Figure 1) connected to a Diesel-ECU.

Today diesel engines are controlled by electronic control units (ECU's), performing complex functions. New developed control algorithms should already be tested under real-time conditions in the laboratory before they are applied to the real engine. Hardware-in-the-loop simulation (HIL) is a powerful tool for development and test of the control algorithms implemented in the ECU's. Modern diesel ECU's are able to react to rotary oscillations of the crankshaft within a work cycle in order to control idling and running smoothness by a cylinder-individual variation of the start of delivery and the injection time. As a consequence also the simulator has to be able to generate torque oscillations with a resolution adapted to the sample rate of the ECU. The paper describes a high resolution real-time model which was designed by expanding a steady state model by a parallel thermodynamic model with a simplified structure.

Advanced automatic transmissions are controlled by electronic control units (ECUs) which perform the gear change and furthermore a lot of complex control and diagnostic functions. Hardware-in-the-loop simulation (HIL) is a powerful tool to develop and test the control algorithms implemented in the ECUs. The simulation is based upon mathematical models of the different power train components, adapted to the real-time requirements. In this paper an improved real-time model of an automatic transmission with a Ravigneaux planetary gear train is presented. This transmission contains among other components numerous clutches and brakes. The time-variant states of these nonlinear elements (sliding and static friction) lead to numerical problems with respect to real-time simulation. In the suggested model the transferred torques of the different clutches and brakes are calculated using the methods of multi-variable control.

Advanced passenger car control is based on multiple electronic control units (ECUs), performing complex control algorithms and diagnostic functions for the different power train components like combustion engine, automatic transmission, brakes or chassis. For research and development the engineers need tools to test and verify either the reliability of new control strategies implemented in the ECUs or the interaction of different ECUs in a car. These tests should be done to the highest extent in the laboratory to reduce costs and risks which are involved in test stands or experimental cars. Therefore the optimal solution is the operation of the ECUs in a real-time closed loop environment.

In the research project “New Exhaust Emission Concept”, supported by the Minister of Research and Technology of the Federal Republic of Germany, the main goal was the minimization of the raw exhaust emission of a gasoline engine by operating the engine in its (HC +NOx)-minimum, as well as the improvement of its fuel economy. With respect to these goals it was necessary to develop new control strategies. To preadjust the appropriate electronic control systems already in the laboratory, a real time simulator was developed, to reproduce the sensor signals of a gasoline engine under steady state, but also under dynamic conditions. The paper gives a survey over the technical specifications of the simulator, the method of mathematical engine modelling, the simulation algorithms and the used hardware solution. Some characteristic results show the performance and the adventages of the use of the simulation system.