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calibration that allow us to evaluate the characteristic 2 2 F O C U S shifting curves in view of their drivability. For example, we investigate whether the engine’s torque prior to downshifting is optimally utilized, or whether the gear shifting processes are working together smoothly. We then use these data to perform an objective assessment of the vehicle’s acceleration behavior, which plays a key role for its brand DNA,” points out Gerhard Kokalj. One big advantage of this AVL methodology is that it can all be done offline, i.e. without a physical vehicle. The expert continues: “To be able to produce an objective evaluation of the gear-shifting strategy or the acceleration behavior, all we need are the relevant vehicle and powertrain data and the transmission’s characteristic shifting curves – and this applies for conventional and electrified drive systems alike. This novel AVL methodology, which demonstrates very clearly how the vehicle’s acceleration behavior and performance feels to the driver, is attracting great interest among our customers. It additionally allows us to compare different vehicles in view of their acceleration behavior.” AVL HYHAB METHODOLOGY After defining the vehicle DNA – and thus an essential goal for the subsequent calibration – the HyHab technique is put to use, a methodology developed by AVL. HyHab is a very efficient way to combine offline calibration with automated test bed runs. In an initial step, the simulation tool AVL CRUISE is deployed to create a model of the entire vehicle, and virtual tests are run to determine the underlying operating strategy. The resulting base data are then saved in the hybrid control unit (HCU) and the vehicle is tested on the powertrain test bed or chassis dynamometer. During the test, an event might be initiated automatically every eight seconds, for example. AVL DRIVE, another AVL tool, is then used to measure the effects on drivability. After that, the control unit parameters are optimized offline again, using the AVL CAMEO tool. In simple terms, CAMEO delivers suggestions to the calibration engineer, indicating which control unit parameters are best suited for achieving the goal. Drawing from the calibration engineers’ extensive expertise, the calibration is then completed for the respective vehicle. The validation finally takes place during test drives in a prototype vehicle. All in all, AVL’s new methodology, which is employed both in hybrid and electric vehicles, offers a substantial number of advantages. By objectively assessing the acceleration behavior, i.e. the gear-shifting points, it is possible to define a vehicle’s DNA entirely offline, based on data. The goal of the subsequent calibration is to achieve this “target DNA.” In conjunction with the HyHab method, it is then possible to develop a vehicle in the course of the calibration process at AVL, which fully satisfies all of the customer’s specifications. Gerhard Kokalj: “With our tools, methods and processes, we can bring vehicles right up to serial production, fast and efficiently – irrespective of whether they have conventional or hybridized drives. The fact that fundamental development tasks are being shifted away from the vehicle toward the test bed and offline development environment plays a crucial role. The AVL methodology is naturally also suited for calibrating all-electric vehicles, but in my opinion, it will be a few years before they become more mainstream.” < > AVL HyHab methodology on the powertrain testbed


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