A Real-Time Model of a Common Rail Diesel Engine

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. These results are compared with measured values from a test bench to validate the simulation.