New Cam Profile Design Approach, Analysis and Testing for Extreme High Efficiency Internal Combustion Engine Development

Abstract

<div class="section abstract"><div class="htmlview paragraph">The main objective of this work is to describe the design and testing of novel cam profiles, which are key for efficiency demonstration on a new class of internal combustion engine (ICE). A recuperated split cycle engine (RSCE) has unique demands for valve lift, duration and phasing when compared to a conventional 4-stroke. In particular, good control of the expander intake valve opening (IVO) appears to be necessary to achieve high efficiency.</div><div class="htmlview paragraph">Commercial computer programs available for valvetrains have been developed for conventional 4-stroke engines and, typically, these are focused on profile analysis rather than design. Often, the standards and recommended parameters are derived from historical 4-stroke data that may not fulfill the requirements of a new class of ICE, where boundary conditions have drastically changed.</div><div class="htmlview paragraph">In this paper, the cam profile requirements, functions, design, analysis and test results from a research and development (R&amp;D) program of a heavy duty (HD) recuperated split cycle engine are reported. This included novelties in cam profile generation, technology and the materials used. This work is based on requirements, hypotheses and problem simplifications, supported by virtual validation, FEM analyses, spreadsheet calculations, component specifications and 1D simulations. Development has also been done by suppliers to satisfy the project requirements, alongside a compromise between technology selection and the pressing need to respect an extremely short time frame for component procurement.</div><div class="htmlview paragraph">Whilst this work refers to a specific engine development program, the methodology described in this paper has been more generally considered for the new class of ICE and can be successfully applied to other projects with common development targets (time to market, fuel efficiency and development costs).</div></div>