At the IAA 2015 the international automotive supplier Continental reinforces its standing as one of the technological drivers for efficient hybridization.
In an independent test in November 2014 done by a German TV station (Vox / auto mobil), Continental’s “48 V Eco Drive” vehicle (Golf VI 1.2 TSI with 48 V technology) showed how it achieves fuel savings of 21 percent in comparison to the series production model without 48 V technology (Golf VI 1.2 TSI equipped as standard with a 12 V start/stop system). Now, at the IAA, Continental is demonstrating even more potential. When the 48 V Eco Drive vehicle is connected to Continental’s eHorizon, the vehicle receives high-resolution road data on the basis of which a control unit adapts the driving strategy in line with the route, thereby enabling even more energy-efficient driving.
“The appeal of connected energy management with the eHorizon is that we can optimize driving strategies in terms of energy usage thanks to an improved database alone,” said Dr. Oliver Maiwald, Head of Technology & Innovations in Continental’s Powertrain Division. “In this way, the control unit can calculate which combination of unpowered coasting and recuperation leads to optimal battery charging and, at the same time, minimizes vehicle friction losses.” The 48 V Eco Drive demo vehicle is a series production VW Golf model with a 1.2 l gasoline engine in which the components of 48 V hybridization have been integrated with only minimal interference in the architecture. Thanks to eHorizon, not only do the drivers of such vehicles benefit from even lower fuel consumption but the support from the electric motor also makes the vehicles more agile than would be possible if equipped with just a consumption-optimized combustion engine. “So the 48 V Eco Drive makes driving more fun, too,” said Maiwald.
Switching off the combustion engine for energy-efficient driving
The high level of efficiency achieved by the 48 V Eco Drive demo vehicle is down both to the recovery of kinetic energy during deceleration (recuperation) and the fact that the combustion engine is switched off as often as possible. Just this driving strategy – known as “coasting” (the combustion engine is switched off and disconnected from the powertrain) – reduces fuel consumption significantly. At the end of this switched-off phase, the 48 V motor restarts the combustion engine very quietly and in less than 0.2 seconds. The amount of fuel potentially saved by this hybrid system is governed by which phases of the journey are used for recuperation and how often the vehicle is permitted to coast with minimal friction losses.
Both intelligent driving strategies are, to a certain degree, in competition with each other. “Since the kinetic energy of the vehicle can be utilized only once, the choice of driving strategy plays a key role,” continued Maiwald.
In the future, data from the cloud will optimize the driving strategy even further.
In static systems, this decision is made solely on the basis of vehicle data. The vehicle is connected via the dynamic eHorizon to the backend, which is where it receives the latest data, for example about upcoming traffic obstacles. “Connecting the energy management system to the cloud will also enable us to utilize dynamic information on traffic flow and other events on the route for energy management purposes in the future,” explained Ralf Lenninger, Head of Innovation and Strategy in Continental’s Interior Division. On known routes (navigation or route detection by adaptive algorithms), the Eco Drive control unit can anticipate when the vehicle should ideally coast and when it should go into recuperation mode. In the applications highlighted, an early signal is output to drivers telling them to take their foot off the gas pedal because they are approaching a stop. In this way, the vehicle can coast without power for as long as possible before going into recuperation mode to avoid the need to deploy the foundation brakes as far as possible. Likewise, the coasting phase can begin just before a road section with a speed limit. Depending on the altitude profile of the route as well as any bends, intersections, and traffic signs, this allows the driving strategy to be adapted to suit the route. “Overall, this reduces fuel consumption by an additional 2-3 percent,” said Maiwald.