Several approaches have been developed to measure instantaneous friction between the piston assembly and cylinder in internal combustion (IC) engines, such as floating-liner, reciprocating liner, instantaneous mean effective pressure (IMEP), fixed sleeve, and (P-ω) method and tribological bench tests. However, the “floating-liner method” and the “(IMEP) method” are the most common methods used to measure instantaneous friction between the piston assembly and IC engines. This paper critically evaluates different approaches to the design of the “floating-liner”. The paper begins by discussing piston assembly frictional losses and their significance and then discuss the development of instantaneous piston-friction measurements. After that, it reviews the main design challenges in the floating-liner approach. “Methods of cylinder sealing” and “force balancing methods” are also reviewed. Design challenges associated with firing operation were presented. Floating-liner designs were classified into different categories with a detailed presentation of the features of each. The paper ends by presenting a range of broad recommendations for further work which would benefit future designs.

Tribotronic machine elements achieve active control by incorporating sensing, control and actuation into engineering components that are otherwise conventionally passive. There has been a trend towards the development and use of active tribological (tribotronic) components over recent years. This paper briefly recounts the historical development of tribotronics, then presents two examples of research on components as case studies based on research by the authors to demonstrate how tribotronics can drive forward the technical capabilities of two common machine elements. In this context, this paper deals with the tribotronics of tilting-pad thrust bearings as well as active lubrication for internal combustion engine cylinder systems. The aim of the paper is to demonstrate how tribotronic technology can be applied to realise transformative reductions in energy loss by controlling friction well beyond those that could be gained by more conventional improvements in design or the use of enhanced materials, In addition to the technical discussion, this paper incorporates a short reflection the very significant financial and environmental gains that can potentially be obtained by using tribotronic components in the field. Finally, closing remarks are made regarding the more general advantages of tribotronic approaches and the potential future of this technology.

Torsional stiffness comes as a priority in chassis design as it greatly affects its dynamics. According to the literature survey done in this research, it shows that the design methodology of tubular space frame was not performed explicitly, so there is a great need to fill this gap. Therefore, this research aims to develop a methodology for designing tubular space frame of vehicles and in other applications. A finite element model was made to evaluate torsional stiffness of vehicle frame then the model results were validated with experimental data obtained from a previous experiment. A parametric study was conducted using this model to investigate the impact of varying tube cross sections, length ratio, triangulation, intermediate sections and materials on both frame stiffness and frame stiffness to weight ratio. From this study, several guidelines for designing tubular space frame were concluded and a design methodology for tubular space frame was deduced.