The powertrain is the largest excitation source of automotive noise and vibration. Torque variations from the engine cause noise and vibration in two frequency regimes: Engine firing fluctuations at the engine rotation frequency and its harmonics and driver-demanded propulsion torque variations at lower frequencies. This paper examines the mechanisms of gear rattle noise caused by engine firing fluctuations and shock and jerk caused by propulsion torque variations. Gear rattle behaviour is simulated and various approaches for reducing gear rattle are investigated. It is found that isolation of engine firing fluctuations from the transmission is the most effective practical way to reduce rattle. Torque profile shaping by robust control is a method that can be used to reduce shock and jerk. A pre-compensator approach based on knowledge of the driveline resonant properties is proposed and the sensitivity of the controller to errors in the assumed resonant frequencies is investigated. It is shown that one of the constraints of this strategy is that the resolution of control system depends on the firing frequency.
Input Torque Shaping for Driveline NVH Improvement and Torque Profile Approximation Problem with Combustion Pressure
Lect. Notes Electrical Eng.
2012-11-07
15 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
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