Development of a diagnosis of an electrically heated catalyst for Diesel application

In recent years, the automotive sector has been experiencing a series of challenging changes as a result of regulations with increasingly stringent emission limits. It is precisely with this in mind that FPT Industrial is developing a new technology that makes possible to improve the ATS (After Treatment System) currently available on the market for light duty commercial vehicles. Specifically, FPT is developing an eCAT (electrically heated CATalyst) mounted upstream of the DOC (Diesel Oxidation Catalyst) in order to improve vehicle emissions and reduce the massive use of post injections and the related disadvantages during DPF (Diesel Particulate Filter) regeneration and light off time. The aim of the project is the development of a pin-pointing diagnosis of the new technology; this will be implemented in the ECU (Electronic Control Unit) that, in this way, will be able to identify any malfunctions of the new electrical element with respect to the existing identification of the chemical DOC. The study began by the reverse engineering in Simulink of the currently imple??mented diagnosis for DOC (chemical) during DPF regeneration. Furthermore, a temperature model has been developed to study the effect of the electrical power on temperatures in the ATS and on present devices. This allows important conclusions useful for the consistency of the existing chemical diagnosis during DPF regeneration: post injections cannot be completely avoided in regeneration, but only reduced, otherwise DOC diagnosis would rarely occur. Then, a proper analysis has been performed with measurements obtained thanks to INCA and MDA to demonstrate the robustness of the diagnostic function. The power effect has been studied first with measurements got on an IVECO Daily with a conventional DOC, then on the same vehicle with the eCAT fitted. Finally, the diagnosis for the eCAT has been developed. Since the part to be diagnosed is the electrical one, it is advisable to run the diagnosis in normal mode or in rapid heat up where post injections contribution is limited. As with all the diagnostics, the definition of the release conditions has been crucial. Among the most important, the definition of a minimum electrical energy window for the evaluation.