Abstract
This paper presents a simulation model of a starter and its performance curves. On the end of every manufacturing line of starters there is a test stand that measures the performance curves of the starter. This gives important parameters for the validation process of the starter. These curves are given by the following functions: torque, rpm, voltage, output power, input power, and efficiency versus current. An internal combustion engine can not start itself, so it needs an outer starting system. The torque needed to rotate the main shaft of the internal combustion engine is quit big and depends on many parameters, such as: engine cycle type: Otto or Diesel, volume of engine, number of cylinders, value of compression, type and quality of lubricant, temperature, etc. The battery gives DC voltage so the easiest solution is to choose a DC motor as starter. There are different kinds of DC motors. The series DC motor has the most convenient mechanical characteristic (rpm versus torque) to satisfy the needs of the smooth starting process. Nowadays, in the case of smaller internal combustion engines, we can find permanent magnet DC motors, too. Moreover, there are investigations to combine the starter and the generator. Couple of years ago it was applied the shunt DC motor - dynamo, but nowadays there is a high advance given by AC synchronous motor - generator. We can meet starter-generators built in the so called micro-hybrid vehicles, which main function is the startstop operation. Interesting solution is given by the ISAD (Integrated Starter Alternator Damper) system. It can be mentioned as new solutions the total elimination of the starter that can be done in the case of the direct fuel stratified injection (FSI) engines.
Keywords: automotive electric systems, starter, simulation, performance curve.