Design optimization study of a nonlinear energy absorber for internal combustion engine pistons
journal contributionposted on 21.05.2018, 15:29 by Nader Dolatabadi, Stephanos Theodossiades, Steve Rothberg
Piston impacts against the cylinder liner are the most significant sources of mechanical noise in internal combustion engines. Traditionally, the severity of impacts is reduced through the modification of physical and geometrical characteristics of components in the piston assembly. These methods effectively reduce power losses at certain engine operating conditions. Frictional losses and piston impact noise are inversely proportional. Hence, reduction in power loss leads to louder piston impact noise. An alternative method that is robust to fluctuations in engine operating conditions is anticipated to improve the engine's NVH performance, whilst exacerbation in power loss remains within the limits of conventional methods. The concept of Targeted Energy Transfer (TET) through the use of Nonlinear Energy Sinks (NES) is relatively new and its application in automotive powertrains has not been demonstrated yet. In this paper, a TET device is conceptually designed and optimised through a series of parametric studies. The dynamic response and power loss of a piston model equipped with this nonlinear energy sink is investigated. Numerical studies have shown a potential in reducing the severity of impact dynamics by controlling piston's secondary motion.
The authors wish to express their gratitude to the EPSRC for the financial support extended to the Encyclopaedic Program Grant (EP/G012334/1), under which this research was carried out. Thanks are also due to the consortium of industrial partners of the Encyclopaedic project, particularly to Capricorn Automotive in this instance.
- Mechanical, Electrical and Manufacturing Engineering