b'Engineer Innovation | AutomotiveBalancer shafts Crankshaft DMF Generatorto PWT to PWT from batteryFigure 2: Hybrid driveline torsional model including combustion engine and generator to study ICE restart vibrations. Simcenter Engineering would helpwhen an engine starts, body vibrations Honda to couple their valuable butare caused by the rigid body compartmentalized knowledge into aneigenvalues of the power plant during integrated solution approach. initial combustion. The difference between normal start and restart In order to properly capture andhowever, is that we expect these resolve the coupling issue as soon asvibrations to occur in the former case. possible, and before prototypeWhile expectations are difficult to availability, Simcenter expertsobjectify and therefore generalize, the introduced us to the Simcenteronly effective strategy seems to be to Amesim systems simulation software,reduce restart vibrations to their Watanabe explains. With this software,absolute minimum, without Honda managed to build fullycompromising engine performance.integrated engine and vehicle models, which were scaled to take into accountConventionally, prediction of noise and combustion, mechanics and controls.vibration phenomena from the powertrain uses a method that inputs A subtle but significant difference the measured in-cylinder pressure Due to the psychological and largelyvalues as a source of engine vibration. subjective factors at play, the restartHowever, departing from a fixed issue is more intricate than sciencein-cylinder pressure value, these would lead one to suspect. Typically,models do not consider the parameters for engine cranking and firing, which contribute greatly to engine restart By predicting systemsvibration, says Tom Van Houcke, a Simcenter NVH expert closely involved behavior upfront, thethroughout the project. Using Simcenter Amesim software, workload afterwards isSimcenter Engineering experts and Honda set out to develop a new significantly reduced, whichprediction technique and a new evaluation method for engine restart vibrations. Honda can now accurately allows us to focus our effortspredict the entire powertrain restart process, beginning with the vehicle and resources on othercontrols signals causing a certain in-cylinder pressure, which then results into driveline torque, particular priorities, such as brandsuspension and powertrain bushing interface forces and eventually body image and value.vibration shock. Allowing for the in-cylinder pressure to Satoshi Watanabe deviate, Honda can now determine the Model-Based Development for Powertrain NVH parts characteristics for the engine Honda R&D Co., Ltd restart vibration in the vehicle design 46'