During recent years, some producers of vehicles with combustion engines have been caught using “defeat devices”. The engine calibration or operation of the emission controls can detect an ongoing type-approval test cycle and only then apply full-blown exhaust gas cleaning. Under regular road use, the behaviour changes and the pollutant emissions increase. It may be beneficial for the driving experience and the life span of the exhaust gas cleaning systems, but it is bad for the health and the environment, and it is probably also illegal.
Detecting defeat devices is not easy since they are hidden in computer code on-board the vehicle, but it can be done. The International Council on Clean Transportation (ICCT) has recently published an article on the topic: “A Step-by-Step Methodology for Vehicle Testing to Catch Defeat Devices”. A key activity suggested by the ICCT is to change driving variables one at a time to identify step changes in the emissions. Examples are given where the ambient temperature was found to change the control characteristics of the exhaust gas recirculation (EGR) in two widespread passenger car models. Another key activity is to run robust road tests, monitoring the real driving emissions (RDE).
If you are in need of robust RDE systems, then OPSIS can supply them to you.
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Operative Support, OPSIS AB