No easy fixes for VW diesels, experts say

Volkswagen may face a significant challenge in getting nearly 500,000 diesel-powered cars in the U.S. into emissions compliance.

The ideal fix would be a solution that reduces the on-road emission of nitrogen oxides without:

• Degrading performance or fuel economy. A reduction of either would likely trigger even more class-action lawsuits from disgruntled Volkswagen owners. 
• Adding significant equipment the vehicles weren't designed for, such as a selective catalytic reduction, or SCR, system. Doing so would require major surgery on each vehicle to install the parts, and it would open up a host of other issues, such as crashworthiness of the new parts. 
• Taking too long to implement the fix. Before his ouster last week, VW CEO Martin Winterkorn said the company is working on a fix. A recall in December to update engine software was not successful. This suggests VW may not be ready with a solution that would stand up to heavy scrutiny from regulators and consumers. 

VW has said 11 million cars are affected worldwide and has set aside $7.3 billion -- that works out to $664 per car -- for repairs and other related costs. It's unknown how much of that money is allocated for software patches or hardware upgrades. 

"I suspect there will be some sort of hardware intervention," said Nick Molden, CEO of Emissions Analytics, a company that tests vehicles for emissions and fuel economy. That intervention, he said, could involve installing a better lean NOx trap, or LNT, to lower emissions. "My theory is that due to the sheer competitiveness of the U.S. market, VW undersized the LNT to get better fuel economy," said Molden. 

The trap is loaded with expensive precious metals, such as platinum and rhodium. A larger trap to increase the efficiency would use more of those metals. Also, suppliers would need time to produce nearly 500,000 traps. 

A calibration expert at a top global automaker also says VW is probably looking at a hefty bill to bring the cars into compliance. The expert, who spoke to Automotive News on the condition of anonymity, said that either fuel economy would decline or costly emission-reduction hardware would have to be added.

"It is difficult to imagine that the software could be updated to always meet emissions without impacting fuel economy or emissions," the expert said, "or the defeat device would not have been used from the beginning."