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Hybrid vehicles are characterized by a combination of mechanical, electrical and control components. The complexity of this mechatronic system requires new methods and tools for a successful development of new hybrid vehicle concepts. It is now possible to accomplish certain tasks earlier in the development projects using virtual prototypes of the powertrain components and the vehicle. The process called “frontloading” integrates simulation, optimization and validation in earlier development phases of a vehicle and prevents from having cost intense problems in later development phases. Besides the reduction of emissions and fuel consumption also the subjective impression of the vehicle driveability are main goals for the optimization of hybrid powertrains.

Highest grow or highest attention in vehicles power-train is related to AWD and hybrid concepts. Some of the targets for these technologies are conflicting, others are very similar, and sometimes it depends on the application. In a first look it is very questionable weather these technologies should be combined. But it can be shown, that the combination makes quite some sense. It is possible to get the superior performance and enhance safety combined with reasonable fuel economy by hybridizing an AWD powertrain. From simulation to testing, efficient processes and a consistent development platform is key to fulfill all the development tasks in the environment of this increased complexity. Simulation and benchmark activities are valuable in the early project phases to define the targets and create the specifications. In the virtual world the system selection is a major task. To get appropriate results software modules are incorporated in the simulation environment.

In a fast and cost-efficient powertrain development process several optimization and validation tasks are required at early development stages, where prototype vehicles are not available. Especially for hybrid powertrain concepts the development targets for fuel consumption, vehicle performance, functional safety and durability have to be validated on the engine test bed before integration and testing with real vehicle prototypes takes place. The integration of relevant control unit functions like transmission shift or vehicle stability as AUTOSAR software component into a simulation system at the engine test bed allows a fast and integrated workflow for series development. Complementary a high-quality combustion torque estimation and the consideration of driver behavior and lateral vehicle dynamics improve the correlation of simulated to real world driving maneuvers.

For the development of complex control algorithms and strategies the engine and powertrain test bed offers a number of advantages over the development in the prototype vehicle. The paper discusses how state-of-the-art simulation techniques can contribute to a continuous development process, which is based upon offline simulation using hardware in the loop, the utilization of modern test bed technology up to vehicle adjustment. The integration of hardware-in-the-loop testing together with vehicle and transmission simulation on the testbed allows to speed up the optimization of fuel consumption, emissions and driveability in an early stage in the development process. The available software tools are presented and application examples are given.