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The new generation of automatic transmissions is characterized by a compact and highly efficient design. By the use of a higher overall gear ratio and lightweight components combined with optimal gear set concepts it is possible to improve significantly fuel consumption and driving dynamics. Precise and efficient real time models of the whole power train including models for complex subsystems like the automatic transmission are needed to combine real hardware with virtual models on XiL test rigs. Thereby it's possible to achieve a more efficient product development process optimized towards low development costs by less needed prototypes and shorter development times by pushing front loading in the process. In this paper a new real time model for automatic transmissions including approved models for the torque converter, the lock-up clutch and the torsional damper are introduced. At the current development stage the model can be used for comfort analysis and drivability assessment.

Cost- and time-efficient vehicle development is increasingly depending on the usage of adequate software tools to enhance effectiveness. The aim is a continuous integration of simulation tools and test environments within the vehicle development process in order to save time and costs. This paper introduces a procedure to reveal the cause of low-frequency powertrain vibrations and the influences on the dynamic behavior of a vehicle on a roller test bench. The affected longitudinal acceleration signal is an arbitrative criterion for the driveability assessment with AVL-DRIVE™, a well-known driveability analysis and development tool for the objective assessment concerning NVH and driveability aspects of full vehicles. These experimental studies are embedded into an approach, which describes the functional assembly of three applied test environments "road," "roller test bench" and "simulation" with according tools in order to facilitate an integrated driveability development process.

In this article a new approach for a combined optimization of performance, emissions, fuel consumption and driveability is presented. Traditionally the development of performance, emissions and consumption takes place on drivetrain testbeds and on chassis dynos. The development of driveability is done in vehicle tests very late in the development phase for which AVL-DRIVE™ is used by many OEMs for the objective evaluation of driveability. The so-called “Vehicle Simulation Model” VSM is a framework for the simulation of driveability in real time. Its flexible model structure as well as the tight connection to AVL-DRIVE™ offers the possibility to integrate the optimization of driveability in earlier development steps and therefore neglect repeating loops in the development caused by e.g. not fulfilled driveability targets.

The paper describes the methods used to select appropriate engines for renewing an existing fleet of fork lift truck models with new Diesel and LPG engines. The target was to achieve a better performance with the new engines and to find a better cost / benefit ratio for the customer. The aid of a simulation was used to fulfill this task. Selecting suitable engines from a variety of industrial and mass production passenger car engines which fulfill above requirements seems to be an easy task on first sight, but looking at the details the matter becomes more complex. Of particular interest were the effects of replacing naturally aspirated (NA) engines by smaller swept volume turbocharged (TC) engines. A power train simulation model including the hydraulic lift part was developed and used for Diesel and LPG engines. For several different operating situations and load profiles a set of simulations was performed for different engines.

The well-to-wheel CO2 emissions and energy use of internal combustion engines (diesel and gasoline) are compared to fuel cell automotive propulsion systems. The fuel cell technologies investigated are polymer electrolyte fuel cell (PEFC), alkaline fuel cell (AFC) and solid oxide fuel cell (SOFC). The fuels are assumed to be produced from either crude oil or natural gas. The comparison is based on driving cycle simulations of a mid-class passenger car with an inertia test weight of 1350 kg. The study shows that the optimized diesel drive train (downsized mated to an integrated starter generator) achieves the best overall energy efficiency. The lowest CO2 emissions are produced by compressed natural gas (CNG) vehicles. Fuel cell propulsion systems achieve similar or even better CO2 emission values under hot start conditions but suffer from high energy input required during warm-up.