An investigation on impact-induced oscillations and noise in lubricated conjunctions
conference contributionposted on 18.09.2017, 13:55 by Nader Dolatabadi, Stephanos Theodossiades, Steve Rothberg
Energy efficiency and Noise, Vibration and Harshness (NVH) have been in the centre of attention for automotive manufacturers during the last decades. Energy losses occur in different forms, such as friction, impacts and noise. Physical understanding of the mechanisms that lead to aggressive dynamics and noise generation is a key in order to design more efficient systems with better NVH performance. In the current study, impact energy is calculated at the lubricated piston-liner conjunctions combining dynamics and tribology. The vibration power at the engine block surface is converted into sound pressure level (SPL) at any desired location analytically. Then, a technique is presented to reduce the severity of impact dynamics by controlling piston's secondary motion, comprising vibration absorbers with nonlinear characteristics. The piston secondary motion dynamics are studied and the absorber effectiveness on vibration reduction is discussed.
The authors wish to express their gratitude to the EPSRC for the financial support extended to the Encyclopaedic Program Grant, under which this research was carried out.
- Mechanical, Electrical and Manufacturing Engineering