ADAC: diesel retrofitting works

Stuttgart, 21. February 2018

The subsequent installation of a SCR-exhaust gas cleaning can reduce the emission of nitrogen oxides from Euro 5 diesel engines in urban traffic by about 70 percent. This is the main result of the test results of the ADAC W├╝rttemberg presents now.

Euro-5 Diesel passenger Cars and vans

For the Test four Euro 5-diesel vehicles used were purchased. It was one to five years old vehicles with 20,000 to 95.000 miles on the odometer: a Mercedes B 180 CDI, Opel Astra Sports Tourer 1.7 CDTI, VW T5 Multivan 2.0 TDI and a Fiat Ducato 130 Multijet. Thus, were covered in addition to passenger Cars in the city often, driving delivery vehicles, attention was also paid to possible different displacements and as widely as possible.

Measurement on the test bench and on the Road

First, the emissions were measured in the unmodified state, both on the test bench in the WLTC cycle, as well as in the real operation on the road to RDE-Standard. Thereafter, the cars of companies like HJS or twin tech were converted and measured again.

NOx reduction by 70 percent, and more

Prior to the conversion, the real-world nitrogen oxide emissions were partly down dramatically over the legal limit, then they were significantly lower. On the test bench, start for the city of NOx, in the case of cold-reduction rates between measured 44 and 61 percent (WLTC cold, 23 degrees Celsius, phases 1-3). Extra-urban (WLTC Phase 4), three systems, even between 78 and 88 percent. Once the systems have reached their operating temperature (WLTC warm, 23 degrees Celsius, phases 1-3), the reduction rates at all well-tuned systems, but also in city traffic at about 70 percent.

The potential for optimization at low temperature

As you know, since the VW scandal, give bench test results, the emissions in real traffic. But also on the street level of the ADAC significant reductions, even under very adverse conditions (outdoor temperature of about four degrees Celsius), such as the measurement results show, the Mercedes B-class and the Opel Astra. Overall, however, it is clear that the SCR retrofit at low temperatures and potential for optimization, the ADAC.

19 to 30 percent less at the Neckartor

A NOx reduction on the vehicle of 70 percent is not to say, however, that the nitrogen oxide readings fall on the road to this value. If performance relative to 75 percent of Euro-5 Diesel passenger Cars were to be retrofitted, the 70 percent of the nitrogen oxides back can hold, would decrease the emissions of road transport at Stuttgart Neckartor (one of the nationwide NOx Hotspots) to 18.5 percent. In the case of more optimistic assumptions up to 30 percent would be possible.

More of Adblue is estimated to be needed as often

In the ADAC measurements also showed that the fuel consumption is increased by the retrofitting of one to six percent. The Adblue consumption was 1.5 to 2.8 liters per 1,000 km is significantly higher than the often used by car manufacturers specified estimated number of one Liter per 1,000 kilometers.

Legislators and car manufacturers must help

The ADAC installed SCR systems were still prototypes. Before the systems can be manufactured in large series, you must first set the legislature a framework for the certification and Verification. In addition, the cooperation of the car manufacturer is important in order to lead the systems quickly ready for series production, the ADAC. And, not least, the financing of the Whole must be clarified. The cost of the retrofits were, according to ADAC, at 1,400 to 3,300 euros, including installation, and the automobile club believes that the average value will lie in the upper third of this range.

It is sufficient for the limit?

The ADAC has not commented as to whether the retrofit would be sufficient to achieve the nitrogen oxide limits in the cities. That appears doubtful. Because, for example, at the Neckartor in 2017, the year was average, according to the Federal environment Agency at 74 micrograms per cubic meter. The are about 80 percent more than the limit value (40 micrograms). Because Euro-5 Diesel passenger Cars are only a part of the nitrogen oxides. According to the ADAC, they deliver at the Neckartor with 34 percent, while the skin contribution, however, Euro-6 Diesel (26 percent), Euro 4 Diesel (ten percent), as well as older Diesel and gasoline engines.(sl)