Hardware-in-the-loop simulation for the design and testing of engine-control systems

For the design, implementation and testing of control systems increasingly hardware-in-the-loop (HIL) simulation is required, where parts of the control loop components are real hardware and parts are simulated. Usually, the process is simulated because it is not available (simultaneous engineering), or experiments with the real process are too costly or require too much time. The sensors and actuators may be simulated or real and the controller is real hardware and software. The real-time requirements for the simulation depends on the time scale of the process and the simulated components. The contribution gives first an overview of the various kinds of real-time and HIL simulation. Then, two cases are considered. First the HU, simulation for relatively slow processes, like in basic industries or heating systems. Here, the simulation-speed may be limited either by the complexity of the processes or by the real controller hardware. Then, the HIL simulation of combustion engines both with transputers and digital signal processors is shown in detail. The required models for 6- and 8-cylinder diesel engines are described, including fuel injection and burning, pressure development, torque,generation at the crankshaft, exhaust turbocharger dynamics and the vehicle dynamics. The MIL-simulator test bench consists of a real-time computer system, sensor-interface, actuator interface, real injection pumps and the real control unit. Comparisons of real-time simulation with measurements on real diesel engines and trucks are shown. The goal of the HIL system is to develop new control algorithms and to investigate the effect of faults in sensors and actuators and the engine itself. Copyright (C) 1998 IFAC.