Abstract
Prospective focus of the automotive industry will be the reduction of CO2-emission respectively fuel consumption. This focus also supports the development of new drive systems and new vehicle concepts [Alb11, Lie11, Kuc11].
With respect of the continuously interaction of the systems “vehicle”, “driver” and “environment”, increasing the energy efficiency of the system “vehicle” is a first step to reach the formulated goal of maximum reduction. This is already realized by e.g. optimization of assemblies or e.g. by implementing operating strategies for subsystems like engines or transmissions. However, inappropriate interaction of the systems “driver” and “vehicle” can influence the theoretically gathered advantages in a negative way. Consequently fuel-saving strategies have to take driver the systems “driver” and “environment” into the loop, as for example applied in driver guidance systems [Alb11]
For supporting the product development process of mentioned above systems, the IPEK X-in the-loop approach for drivetrain systems - as presented at FISITA 2010 - has been established. It is a validation methodology, which contains all the steps from properties (WSP) up to the complete vehicle and that consequently considers the interaction of the systems “vehicle”, driver” and “environment”. [Alb10]
Obviously, to release the highest fuel consumption reduction being possible, the two separate methods cited above – optimization of the vehicle and driver guidance - have to be merged into a new method. In doing so, especially the topic drive comfort has to be particularly respected. This is important, as research in the area of fuel efficiency has shown that e.g. inconvenient driving maneuvers can occur [Ben04, Fia06, Gre00]. This new method is based on the system “driver” and its driving behavior, also taking the system “environment” into account. This behavior spans the solution space for a convenient “operating performance” of the vehicle [Alb11, Alb11a].
Adapted from this solution space, the overall system “vehicle” is optimized; including e.g. assemblies, operating strategies and fuel saving driver guidance systems [Alb11a].
Therefore, the IPEK X-in-the-loop approach for drivetrain systems was advanced by optimizers. This enables a target-oriented, partially automated return of generated system knowledge. Thereby the interaction of the systems “vehicle” (e.g. component, controls) as “driver” (e.g. driving behavior) and “environment” (e.g. road topology) is consequently considered.
This novel integrated modular maneuver and road based optimization environment was developed and implemented and is valid for conventional drivetrains, hybrids and as well applicable for electric cars. Thereby, depending on the task the optimization algorithms can be changed; the solution space can be preset, the track and its topography can be chosen and the vehicle with its subsystems can be simulated.
KEYWORDS: CO2-emission reducing, vehicle operating strategies, drive comfort, IPEK X-in-the-loop optimization framework