F2008-12-023
Quantifying the Customer Benefit of a Parallel HEV in Real Traffic
Given the fact that fossil energy sources are limited and in view of the CO2 discussion and political constraints regarding the vehicle emission limitation, the OEMs have focussed on the development of alternative drive concepts for several years. One of these concepts is the parallel HEV, which is, in different development stages, already on the market. The manufacturer´s data in terms of fuel consumption are determined in standardised cycles, e.g. NEDC. These data, however, do not correlate sufficiently with the experiences achieved in practice.
In this regard, a holistic approach is introduced by means of which the driver behaviour in real traffic can be determined and represented in a simulation. It is based on the DRV parameter space, which is defined by the parameters driver (customer), vehicle and road (driving environment). Driver is distinguished by driving style. Vehicle considers the system behaviour of the hybrid drive train in the vehicle while road describes where the vehicle is used (road type, traffic management etc.).
The presentation centres on the following aspects: Application of the DRV method for quantifying the customer benefit in a parallel HEV compared to a conventional vehicle. The analysed customer benefit refers to the criteria of consumption optimisation and improvement potential of longitudinal dynamics. The DRV parameter space for viewing the parallel hybrid drive will be introduced. The customer behaviour in a conventional vehicle is compared to a hybrid drive by means of measurements. From this an assumption of how a virtual hybrid concept without hardware and thus vehicle measurements in customer operation can be simulated is derived. The results of the DRV simulations with an exemplary parallel HEV quantify which customer can expect a significantly better fuel consumption from a hybrid drive and in which cases the customer has to expect disadvantages. Further simulation results include different parameters, e.g. the number of restarts of the combustion engine per mileage and customer types or the maximum number of restarts per time unit. These parameters allow the evaluation of the basic operation strategy on the one hand. On the other, these data can also be used for a specific customer-oriented and thus representative dimensioning and system configuration, e.g. impulse clutch between combustion engine and electric machine.
Poster presentation: Simulation and testing