In the development process of actual cars it is more and more important to be able to evaluate in a detailed and fast way the impact, on the fuel consumption, of components and management strategies of the auxiliary systems.
For these reasons, there is the need to develop and test specific tools.
One of the most consuming subsystem is the Air Conditioning system: to be able to integrate it in a dynamic simulation model is going to be of outmost importance in the near future, since it is most likely that in some countries (see incoming California legislation) vehicle fuel consumption will be measured with the A/C system “ON”.
FIAT Auto and Centro Ricerche FIAT have jointly developed a simulation tool, DrivEM, that integrates three dedicated simulation models: Drivetrain© for vehicle performance & fuel consumption, SACS for air conditioning systems and BILELCO for electrical system analysis. DrivEM1.0 allows to estimate the impact on fuel consumption both for A/C system under a whatever ambient conditions using and for electrical power loads needs.
One of the key feature of the approach is that the majority of data, needed as input, do not require experimental tests, but can be derived from suppliers datasheet or from the basic characteristics of the vehicle.
This allows to use this tool since the early stage of the development process of the vehicle itself.
The simulation of vehicle performances with air conditioning and electrical system on has been validated with experimental tests in a test bench with climatic chambers. The accuracy of the comparison between measurement and simulation is within 5%.