Online Monitoring Solutions of Efficiency for Automotive EGR Heat Exchangers

Internal combustion engines are the dominating technology in the automotive transport sector. Within this context, even incremental improvements in efficiency are essential for reducing overall environmental impact. Maintaining rated specifications is also an important issue, with monitoring solutions being more and more the focus of development. Cooled exhaust gas recirculation (EGR) is a well established technology that allows improvements in efficiency and reduction of emissions. The present work looks at different solutions focused on the integration of a digital sensor directly into EGR valves, thus ensuring continuous monitoring and extensive diagnostics. As an initial stage, an evaluation of gas cooling efficiency was performed and different routes were identified to allow this parameter to be monitored online. Measurement of flow was discarded as a solution, mainly due to cost issues and complications of its application. Temperature based evaluation of efficiency was found to ensure the best compromise, with acceptable accuracy and practically no integration difficulties. This initial evaluation allowed the definition of basic principles of operation for the sensor, so as to ensure the final goal of more efficient and longerlasting EGR modules through continuous performance monitoring.