<p>The engine torque is an important control signal. This signal is disturbed by the devices mounted on the belt. To better be able to estimate the torque signal, this work aims to model the auxiliary devices'influence on the crankshaft torque. Physical models have been developed for the air conditioning compressor, the alternator and the power steering pump. If these models are to be used in control unit function development and testing, they have to be fast enough to run on a hardware-in-the-loop simulator in real time. The models have been simplified to meet these demands. </p><p>The compressor model has a good physical basis, but the validity of the control mechanism is uncertain. The alternator model has been tested against a real electronic control unit in a hardware-in-the-loop simulator, and tests show good results. Validation against measurements is however necessary to confirm the results. The power steering pump model also has a good physical basis, but it is argued that a simple model relating the macro input-output power could be more valuable for control unit function development.</p>

The engine torque is an important control signal. This signal is disturbed by the devices mounted on the belt. To better be able to estimate the torque signal, this work aims to model the auxiliary devices'influence on the crankshaft torque. Physical models have been developed for the air conditioning compressor, the alternator and the power steering pump. If these models are to be used in control unit function development and testing, they have to be fast enough to run on a hardware-in-the-loop simulator in real time. The models have been simplified to meet these demands. The compressor model has a good physical basis, but the validity of the control mechanism is uncertain. The alternator model has been tested against a real electronic control unit in a hardware-in-the-loop simulator, and tests show good results. Validation against measurements is however necessary to confirm the results. The power steering pump model also has a good physical basis, but it is argued that a simple model relating the macro input-output power could be more valuable for control unit function development.