ARLA^® Engineering Service

Special Automotive Applications

Typical applications for ARLA's engineering services particularly dedicated to the NVH analysis (NVH = Noise, Vibration, Harshness) of powertrains in cars, trucks, and special-purpose vehicles are as follows:

• analysis of the gear rattling phenomenon considering the backlash in the transmission
   
• tip-in, tip-out (low frequency excitation), creeping
   
• multi-parameter analysis of excitability (natural behaviour)
   

• analysis of the dynamic behaviour of manual (5-speed, 6-speed) and automatic transmissions (CVT = Continuously Variable Transmission,
  DCT = Dual-Clutch-Transmission, new concepts)
   

• interdependences of engine and transmission characteristics
   
• considering typical non-linear effects (clutch, joint discs, dampers,
  DMF=2-mass flywheel, angle or velocity dependent elasticities)
   
• customer solutions (special software modules and engineering tasks)

A typical automotive application is the NVH optimization of the total powertrain of a RWD or FWD or 4WD car with manual or automatic transmissions. One target is the reduction of noise, which is usually caused by the fluctuation of the reciprocating engine. In a special situation the passenger may hear a high frequency noise of the gear ("gear rattling"). All significant drive elements of the system are integrated in the computer model (e.g. reduced engine inertia, flywheel, clutch, gear wheels with backlash, absorber, universal shaft, differential gear, side shafts, tyres). Thus, it is possible to find best powertrain configurations before starting detailed design studies.

There are also special reference applications for the dynamic analysis of engines:

• steady-state simulation for optimum absorber and damper design
   

• special analysis considering integrated starter-alternator-damper-systems
   

• overall engine analysis with all auxiliary drives

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