The simulation of the dynamic load characteristics of an internal combustion engine

This thesis considers the feasibility or replacing a series of diesel engines, which are used in starter-motor endurance tests, by an electrical loading system whose torque-characteristics are similar to those or a given individual engine. The torque-characteristics of diesel engines and starter-motors are briefly examined to indicate the problems associated with their simulation. The ii. simulating system finally evolved is based on a static-switching current regulator and useful contributions are made towards both the physical realisation or suitable circuit-techniques and the general analysis and operation or switching-mode circuits or this kind. Special consideration is given to the problems or rapid and periodic reversal or the regulator output- current, and a static-logic system is evolved that provides this essential facility. Some practicable and novel methods or generating high-frequency functions are presented for the production or torque/crank-angle waveforms for a range of engine-parameters, and proposals are made for the electrical simulation or the engine-inertia. The effects of this latter function upon the system torque requirements and the validity or the overall simulation are then examined in detail. It is concluded that an electrical simulation is possible by use or the techniques suggested, although some complexity is unavoidable if high accuracy and performance are to be achieved.