Recent TNO rapports as annexes to letter of Ministry of Infrastructure and Water management to the Dutch Parliament

Effects of a software update on a VW Polo

In response to a request from Parliament, the Dutch Ministry of Infrastructure and Water management has asked TNO to collect data on the consequences for real-world emissions and for vehicle owners of the software update that has been made available by Volkswagen for cars with a defeat device.

For one VW Polo from the group of cars containing defeat devices the emission behavior has been measured and analysed before and after application of a software update. The vehicle was monitored during a two year period. The software update was found to have hardly any impact on the NO_x emissions, CO₂ emissions and fuel consumption, and engine power.

Measurements for RDW on a Jeep Cherokee and Suzuki Vitara

On behalf of the Dutch road vehicle authority RDW, TNO has carried out emission investigations on a Euro 5a Jeep Cherokee and a Euro 6b Suzuki Vitara, both equipped with a diesel engine. Previous tests by RDW from 2017 yielded results that justified further investigations. The objective of the follow-up investigations carried out by TNO was to measure the NO_x emission behavior of both vehicles before and after an update of the engine calibration software. Emission measurements have been carried out on a test track at the RDW facilities, on a chassis dynamometer and on public roads. For information on the interpretation of the results we refer to RDW.

Investigation into emissions outside the RDE boundaries

Test programmes, carried out by TNO over the last decades, have revealed that the real-world emissions of (mainly) diesel cars are generally much higher than the regulatory emission limits. Cars were found to be optimized on the official laboratory test, used for type approval. Under driving conditions not covered by this test manufacturers used alternative emission control strategies, generally motivated as needed to protect the engine. Since the addition to the type approval test procedure of a measurement on the road (so-called RDE or Real Driving Emissions) in 2017 this has changed: in real-world driving cars must now produce low emissions over a much wider range of driving conditions. But not all driving conditions are covered by the new RDE test. Striking examples are a family of five in a car packed with luggage and equipped with a roof box on their way to a holiday destination, cars towing trailers or caravans, and emissions from engines running stationary when the driver cleans the ice from the windows in winter. How high these emissions outside the RDE window are allowed to be, has not been sufficiently regulated yet. TNO has charted the relevant driving circumstances and has investigated the extent to which it is technically possible to demand low emissions also in these driving conditions. As part of the preparation of new European Euro-7 emission legislation, it is now discussed whether the RDE requirements can be extended.

Relevant reports

• Effect software update VW Polo (TNO 2019 R10541)
• Elevated emissions outside RDE Update (TNO 2019 R10534)
• RDW Jeep Grand Cherokee (TNO 2019 R10635)
• RDW Suzuki Vitara (TNO 2019 R11215)