F2008-06-012
Development of a Compact Hybrid Vehicle with a Foresighted Energy Management System
Facing the continuously increasing traffic density and number of vehicle registrations, a reduction of CO2 emissions is indispensable. Improved engine technologies are one possibility to reduce the fuel consumption. Other possibilities to lower the energy demand of a vehicle are i.e. lightweight materials, improved aerodynamics, low resistance tires and more efficient gearboxes. With the market launch of first vehicles with hybrid drive in Europe this drive concept has been set in the focus of public discussions as an additional promising technology to reduce fuel consumption. General advantages of hybrid vehicles are e.g. an automatic turn-off of the combustion engine during stopping phases and the possibility of energy recuperation while braking. So an urban traffic situation with a dynamic driving profile offers a high fuel saving potential. However, higher speed levels reduce the possible fuel saving. In general, hybrid vehicles have only limited advantages towards conventionally driven vehicles in highway traffic. Thus hybrid vehicles need an adaptation of the driving style to the characteristics of the drive train. The complete saving potential of a hybrid vehicle is only open to a foresighted and anticipatory driver. The aims of the foresighted energy management for hybrid drive systems are to reduce fuel consumption as well as exhaust emissions, to optimize aggregate stress and battery lifetime. A new operating strategy is necessary that considers additional information about the current and following traffic situation. One important question is how the foresighted driving effects the driving comfort and how the drivers will accept this technology. A necessary condition for foresighted driving is the information about the future traffic situation. Vehicle mounted sensors like radar or lidar systems can give dynamic information about the surrounding traffic situation while the digital map of the navigation system offers static information about the street conditions (e.g. inclination, curvature, speed limit). This information will be included in the next generation of digital map. The energy management uses all available information to drive the hybrid vehicle in the most economical way. This is the main topic of the presented project. Based on the latest drive train concepts a foresighted energy management will be developed for a hybrid vehicle and demonstrated in a subcompact vehicle. The build up of the vehicle will be finished by the end of the year 2007 and from January 2008 driving tests with different test persons will start to show the fuel saving potential in real traffic. These tests will show on the one hand the saving potential of the hybridization of the vehicle and on the other hand the additional saving potential of the hybrid vehicle in combination with the foresighted driving strategy. The presentation will explain the build-up of the hybrid drive train including the necessary components like the electric engine and the reinforced gearbox. In addition we describe our traffic pre-emption system and how it influences the operating strategy of the hybrid drive train. Finally we will show how the hybridization effects the driving characteristics as well as the fuel consumption.
Session: Hybrid Powertrains II