Remanufacturability of used pistons

Abstract

In today’s society circular economy and sustainability are becoming increasingly more important as the European Union and industries are working towards the EU’s 2050 climate neutrality target. Circular economy is based on the foundation that the life of a product never reaches the end of life and is instead either repaired, refurbished, remanufactured or recycled. Volvo Group has been working with remanufacturing since the 1960’s, where old parts and components, also called cores, are received and exchanged to a fully remanufactured part with the latest engineering and technical specifications. Currently Volvo Group has no viable process for remanufacturing pistons in heavy duty engines. Therefore, the need to investigate and evaluate the possibility of remanufacturing used pistons is of importance not only from a sustainability perspective but also of concern when adapting towards a more circular economy.

This thesis has mainly focused on investigating and evaluating early stages of remanufacturing where a cleaning test has been performed in order to remove carbon build up that commonly occurs in the combustion chamber of an engine, where the oil cooling gallery and upper compression groove has been of interest. Cleaning is also needed in order to prepares the piston for additive manufacturing as well as machining. By cleaning the pistons in a warm water and a ultrasonic cleaner it was found that initial debris and contamination was successfully removed. However, for the main focus areas, the oil cooling gallery and upper compression groove, a reasonable amount of carbon build up still remained.

It was found from the outcome of the cleaning test that the remanufacturing process heavily relies on further machining in order to fully remove the carbon build up and that future research is needed to fully determine if remanufacturing used forged steel pistons is of benefit for Volvo Group. Further research and testing is also needed in order to choose a appropriate additive manufacturing method that will provide the desired mechanical properties.