Cars from each region will need their own fix, but VW UK boss Paul Willis confirmed that it wasn’t simply a case of one fix for each side of the Atlantic either.
“In Europe, for 1.2 and 2.0-litre diesels we have a software fix – the fix starts on week nine [of this year]. But for the 1.6-litre diesel engine, there’s a software and hardware change that’ll commence from month nine.”
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Schmidt went on to explain that the EA189 1.6-litre diesel engine, which is fitted to 430,000 UK vehicles, will need its flow transformer (which measures the volume of air flow into the engine) changed in order for the software fix to work.
“In the configuration that was brought to production, the onboard computer couldn’t get a proper reading of what was going on, so the actual volume of air was not what we read on the sensor,” he said. “Our new transformer – or flow rectifier as it’s sometimes called – gives you a laminar [smoother] air flow that can be more easily measured.”
This change allows the ECU to accurately inject the correct amount of fuel into the engine, which VW says will improve efficiency.
Schmidt compared the software and hardware fixes with upgrades to smartphones: “What we do on the 1.2 and 2.0-litre is we put new apps on your phone, so we are only changing calibration data. But on the 1.6, we give you a new operating system.”
Willis said VW was confident its fixes would be enough to bring affected diesel engines into line with the law. He added that VW was going beyond its legal requirements to ensure its diesel emissions were reduced.
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“Though the NOx trap we have been using is sufficient to pass emissions tests [with the software fix], we are still going to fit all EU diesels with our SCR system between 2017 and 2020,” he said. “We are also developing all future diesels to work towards SCR systems.”
Questions in the latter parts of the Transport Committee meeting turned from what and how, to ask why illegal software had been written for diesel cars. One committee member asked what motivation VW engineers would have had in developing cheating software for both the EU and US markets, though Schmidt declined to offer a solid answer.
“All I can do is speculate [that it was done] to keep costs down,” he said. “The only thing that comes to mind is people wanted to meet American emission laws with the technology available at the time.”