Further Experiments on the Effect
of Bulk In-Cylinder Temperature in the Pressurized Motoring Setup Using Argon Mixtures 2020-01-1063
Mechanical Friction and Heat Transfer in internal combustion engines have long been studied through both experimental and numerical simulation. This proposal for publication presents a continuation study on a Pressurized Motoring Setup, which was presented in SAE paper 2018-01-0121 and found to offer robust measurements at relatively low investment and running cost. Apart from the limitation that the peak in-cylinder pressure occurs around 1DegCA BTDC, the pressurized motoring method is often criticized on the fact that the gas temperatures in motoring are much lower than that in fired engines, hence might reflect in a different FMEP measurement. In the work presented in SAE paper 2019-01-0930, pure Argon was used as the pressurization gas due to its high ratio of specific heats. This allowed to achieve higher peak in-cylinder temperatures which close further the gap between fired and motored mechanical friction tests. In 2019-24-0141, Argon was mixed in different proportions with Air to synthesize gases with different ratios of specific heats in the aim of observing any abrupt transitions in the FMEP with different peak in-cylinder temperatures. In this proposal for publication, an extension to the test matrix published in 2019-24-0141 is presented, with an engine speed ranging from 1400rpm to 3000rpm and ratios of specific heats varying from that of pure Air (γ=1.4) to that of pure Argon (γ=1.67). The peak in-cylinder pressure was kept at a constant 100bar. Results obtained in this work strengthen further the observations made in 2019-24-0141; where the measured FMEP is insensitive to the different peak in-cylinder temperatures. In this study, a surface thermocouple of the eroding type was also fitted in the combustion chamber and wall temperature histories were recorded. The transient heat flux through the wall was computed through a spectral analysis and reported in this proposal for publication.
Carl Caruana, Mario Farrugia, Gilbert Sammut, Emiliano Pipitone
University of Malta, Jaguar & Land Rover, University of Palermo