Experts blast VW’s explanation for diesel emissions cheating

A top Volkswagen executive on Thursday blamed a handful of rogue software engineers for the company’s emissions cheating scandal and told outraged lawmakers that it would take years to fix all of the nearly 500,000 vehicles affected in the U.S.

“This was a couple of software engineers who put this in for whatever reason,” Michael Horn, VW’s U.S. chief, told a House subcommittee hearing. “To my understanding, this was not a corporate decision. This was something individuals did.”

Horn, chief executive of Volkswagen Group of America, apologized for the scandal and said he learned of the problem only a couple of days before the company admitted it to regulators on Sept. 3.

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“On behalf of our company and my colleagues in Germany and me personally, I would like to offer a sincere apology — sincere apology — for Volkswagen’s use of software program that served to defeat the emissions testing regime,” Horn told the House Energy and Commerce Committee’s oversight and investigations panel.

He revealed that three VW employees have been suspended in connection with the so-called defeat devices in the automaker’s diesel vehicles, which lowered emissions during testing.

“I think it’s dead wrong if you put corporate profits before people,” Horn said.

When the cars were on the road, regulators said they spewed up to 40 times the legal amount of nitrogen oxide.

VW admitted to the cheating last month after being confronted by federal and California regulators. The company’s chief executive, Martin Winterkorn, resigned a few days later in the wake of the scandal, which affects about 11 million vehicles worldwide.

On Thursday, Horn was the first top executive to face public questioning on the controversy. Several subcommittee members reminisced about the VW cars they had owned and expressed anger about the company’s acknowledged cheating.

“I’m your Volkswagen driver who’s always trusted your company, and I’m very disappointed,” said Rep. Morgan Griffith (R-Va.), who owns a 2012 VW Passat diesel car, among those with the illegal software code.

Rep. Chris Collins (R-N.Y.) said it “defies credulity” that a couple of employees were responsible for the scandal.

“I cannot accept VW’s portrayal of this as something by a couple of rogue software engineers,” Collins said. “Suspending three folks — it goes way, way higher than that.”

Lawmakers and others expressed skepticism that the cheating scheme was devised secretly by a handful of engineers.

“There are not rogue engineers who unilaterally decide to initiate the greatest vehicle emission fraud in history. They don’t act unilaterally,” said Joan Claybrook, former administrator of the National Highway Traffic Safety Administration. “They have teams that put these vehicles together. They have a review process for the design, testing and development of the vehicles.”

James Womack, an expert on the international auto industry, also expressed doubts.

“It might not be reviewed and discussed leaving an email or voicemail trail,” Womack said, “but it sure does cause you to scratch your head that we have this software that just happens to be in 11 million cars and no one in the whole company noticed it. I hope someone figures it out.”

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It’s unlikely that VW’s senior management directed a team of software engineers to devise the cheating software, said Logan Robinson, former general counsel at auto parts supplier Delphi Corp. and a former senior attorney at Chrysler.

What’s more likely is that a group of engineers developed “a novel solution” and “floated it upstairs,” he said.

He doubts a handful of engineers “could do this under the radar … have it last for years,” and that there would be no knowledge of management running VW’s regulatory and business wings.

“The engineers would have passed it on up, looking for praise and affirmation of their German engineering skills,” Robinson said.

Horn said he was optimistic the company could fix all the vehicles so they would pass emissions tests without losing performance. He noted the Environmental Protection Agency said the vehicles are legal and safe to drive.

But Horn said fixes would not start until at least next year and it would take multiple years to make the retrofits, which would take five to 10 hours per vehicle. The problem affects models from 2009 to 2015.

Pressed by Jan Schakowsky (D-Ill.), Horn said Volkswagen would consider buying back the cars. Kelley Blue Book estimates the price tag for such a program would reach $7.3 billion for just the vehicles sold in the U.S.

Horn also said the automaker was looking at giving owners rebates to cover the diminished value of their vehicles. Kelley Blue Book estimates that prices for used VW diesels have fallen about 13% since the scandal broke.

About 430,000 of the older VW diesel models use what is known as a “lean NOx trap.” The system collects nitrogen oxide in a device resembling a catalytic converter. Software instructs the car to shoot fuel-rich exhaust into the trap every few minutes, creating a chemical reaction that reduces the nitrogen oxide to plain nitrogen.

But the lean NOx trap that came with the vehicles isn’t big enough to reduce their emissions to within U.S. limits.

VW is considering replacing them with bigger traps, but that also presents a problem. Such systems tend to lose their effectiveness over time, said Addy Majewski, a chemical engineer and the editor of, an emissions information service. They also use up more fuel, which would change the fuel economy of the vehicles.

That’s why other automakers have gone with a method called “selective catalytic reduction,” which injects an ammonia-rich urea solution into the exhaust system. The ammonia and exhaust mixture flow into a catalytic converter where nitrogen oxide emissions are converted into harmless nitrogen and oxygen

It’s expensive — and a key reason diesel vehicles cost more than those powered by gasoline. The system also takes valuable interior space, and the urea fluid tank has to be refueled periodically, adding an extra service expense for drivers.

VW switched to the SCR system in its 2015 models, which is why they can be fixed with a software upgrade. It’s also in the 2012-2014 VW Passats, but Horn said the automaker is still evaluating how to bring those cars up to the standard.

Q&A: What you need to know about the Volkswagen emissions scandal

Horn said the company also is considering retrofitting the older models with the SCR system. But that would be an especially complicated and expensive fix, diesel experts cautioned.

“You have to put in the feedback systems, the computer controls, the plumbing, the SCR catalyst – the vehicles were not designed to incorporate all that stuff,” said Allen Schaeffer, executive director of the Diesel Technology Forum.

The expense could turn out to be more than the value of the car, he said.

A top EPA official told the committee that the agency is investigating the emissions scandal along with the Justice Department and still doesn’t know exactly how the software trick worked.

“We still have many questions for Volkswagen to answer,” said Christopher Grundler, director of the agency’s Office of Transportation and Air Quality.

But he said officials “don’t need to unpack 10 million lines of code” to stop the so-called defeat devices and are focused on getting VW to fix the vehicles.

The EPA wants VW to propose multiple options for fixing the problem to determine which one works best for consumers, Grundler said. 

The California Air Resources Board also will have to approve any solution VW proposes.

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