Abstract
Recently mankind faces the dilemma of balancing between environmentally friendly and economy growth. Car manufactures have a responsibility of realizing sustainable mobility as one of the solution to this dilemma.
The exhausted CO2 is the result of various energy consumptions. In order to reduce the CO2 in the vehicle, various losses should be minimized. As for the electrical energy, amount of used electrical energy should be decreased. For kinetic energy, vehicle mass, air resistance, road resistance should be decreased. As for thermal energy, engine friction, transmission efficiency and air conditioning load should be improved during the very low temperature (cold) starting period. By calculating and optimizing the energy flow above will therefore assist in CO2 reduction.
In order to discuss above energy optimization, the energy flow should be calculated including each interaction of those technical region (electrical, kinetic and thermal energy). Thus using multi-domain simulation technology is indispensable. In doing so, it is possible modelling to treat several energies simultaneously in accordance with the law of the conservation energy. This time, we selected the modelling language of VHDL-AMS (IEEE 1076.1)(1)-(4), which has the capability of applying Kirchhoff’s law to the multi-domain energy simulation as a same topology of electrical circuits. This modelling language is effective to consider multi-domain technology. As it has the notion of through quantity and across quantity of Kirchhoff’s law, and also it allows multi-domain physics to be modelled. At the same time, the Kirchhoff’s law ensures the law of the conservation of energy.
In this paper, by employing thermal characteristic modelling to the main components in the vehicle model such as engine, transmission and battery, we can analyze energy and calculate fuel consumption under several driving patterns especially during warming up process (cold situation). In addition, by analyzing these results, we can quantify the electrical, kinetic and thermal energy during cold situation. Compared to the previous simulation, this multi-domain simulation allows more detailed energy analysis at the realistic situation (air conditioning ON, headlight ON etc) so that the effectiveness of multi-domain simulation can be confirmed. Therefore we can use these simulation results to validate the effect of vehicle components and control systems. This report discusses effects on fuel consumption of the exhaust gas heat exchange system, changing engine friction at cold situation and changing the air conditioning control in detail.
Keywords: Energy analysis, Multi-domain simulation, SILS, VHDL-AMS, HV