After some nine months of diesel misery is a technical solution emerging now: the modifications made by VW on affected vehicles has proved at least on three vehicles as effective. Have the measurements of the three Automobile Club ADAC and ÖAMTC (Austria), TCS (Switzerland) with the support of the FIA (Fédération Internationale de l'Automobile) result.
Examined were three vehicles of the model Audi A4 avant 2.0 TDI with 120 and 136 HP of model years 2013 and 2014, as well as a VW Golf of the sixth generation with the 140 HP strong 2.0 TDI, each with six gears and start stop system. It emerged that in the currently valid EU cycle (NEDC) through the conversion of NOx emissions, nor the consumption changed which means that there is no deterioration.
The results at higher load are probably more important. This sent the tester again on the dyno the cars, but they subjected the realistic WLTC and BAB130 cycles. WLTC stands for worldwide harmonized light-duty vehicles test procedure that is the new cycle of consumption, which originally 2017 should enter into force in the EU, but was stopped by the German Government. He has a higher average speed and a higher maximum speed than the currently valid NEDC and therefore will provide higher consumption levels by 25 percent. The BAB130 cycle is used by the ADAC for its eco-test. The abbreviation stands for Federal Highway at 130 km/h. This is repeatedly accelerated 80 or 110 km/h at this pace.
After the tests, NOx emissions by retrofitting decreased significantly while the consumption in these cycles increased only slightly. With the new software, NOx emissions decrease depending on the vehicle and measuring cycle by up to 12 percent at Audi and up to 36% on VW. Taking into account of the measurement uncertainty of maximum +/-2% results from the tested VW Golf depending on the cycle also a small consumption increase from 0.4 to 2.5 percent.
According to the ADAC, the results indicate that the conversion in the examined two-litre diesel models in real driving can yield environmental benefits. Consumption and engine power are hardly affected then by the conversion. What is striking, however, is that the consumption in the EU cycle already up 7 percent to 15 percent turned out before the software change as the standard consumption indicated by the manufacturer. When the tested VW, the type approval values for CO2 (114 g / km) and fuel consumption (4.3 liters per 100 kilometers) by 7.2 percent were golf or exceeded 8.6 percent.
ADAC and ÖAMTC TCS expressly point out, that the investigation of individual vehicles allow any general statements about all recalled vehicles. The tests give only a first orientation with regard to retrofitting. But vehicle-specific studies are required to establish individual rights. (sl)