Normally companies prefer their news releases to be bite-sized morsels no longer than a page.
So when the media leveled allegations of emissions fraud against General Motors' European unit, the nine-page response detailing GM's position hinted at panic. It was titled "Statement of the Adam Opel AG on the Current Diesel Discussion," but one of Germany's leading newspapers suggested an alternate headline: "The longest denial in corporate history."
Opel's response typified the wariness of automakers swept up in the emissions controversy that has engulfed Europe's diesel industry since the U.S. EPA discovered the fraud at Volkswagen.
Ongoing news reports revealed a reality that might surprise those outside the world of powertrain engineers and regulators. "Defeat devices" gained prominence thanks to VW, which used such software to turn off its emissions controls outside of government testing. But other automakers in Europe make liberal use of officially sanctioned devices in diesel vehicles that emit nearly as many toxins as VW's.
The result is that, even though Europe has mandated a radical decrease in nitrogen oxide, or NOx, emissions over recent years, the use of these "devices" -- essentially software code embedded in the engine control unit -- means that real-world emissions are considerably worse.
A variety of euphemisms such as "engine calibration," "acoustic function," "thermal window" -- or in the U.S., "auxiliary emissions control devices" -- describe conditions under which carmakers may minimize or switch off their expensive exhaust-treatment systems in the name of guaranteeing mechanical durability.
A recent investigation of 53 diesel models by Germany's transportation ministry discovered broad use of these legal defeat devices. For example, officials found a 1.6-liter diesel BMW 2 series emitted more than five times the legal NOx limit on the road. The 1.5-liter diesel in Renault's Dacia Sandero emitted 1,025 milligrams per kilometer on the road -- 13 times higher than the ceiling in the EU's laboratory testing.
Part of the reason the devices are widely used in Europe traces back to a loophole in the European Union's emissions law. In Europe, the law gives automakers wide discretion to use defeat devices to protect the engine or safeguard the vehicle.
Andrew Fulbrook, director of IHS Automotive's global powertrain and compliance forecasting, says the U.S. is less affected because it requires manufacturers to submit a list of such devices.
"It provides the regulator with an opportunity to agree or disagree with the OEM in his interpretation of the definition of an [auxiliary emissions control device] and if it is a defeat device or not," he said. "It's a clear requirement."
In Opel's case, Germany's most influential news weekly, Der Spiegel, ran a cover story accusing the GM unit of using software that instructed its Zafira multipurpose vehicle's diesel engine not to clean nitrogen oxides around 80 percent of the time.
The exhaust gas after-treatment system was set to switch off at specific altitudes, vehicle speeds or weather conditions -- circumstances that seemed to fall just outside the test parameters used in the EU's driving cycle.
Opel denied it had done anything illegal, but did not dispute many of the findings. Instead it dismissed them as "misleading oversimplifications and misinterpretations of the complicated interrelationships of a modern emissions control system."
Ambient temperatures, air pressure and engine load are just some of the 17,000-plus variables taken into consideration by its software, Opel said. As such, fishing out a few elements in isolation of one another presented a distorted picture.
"Such a complex system cannot be broken down into individual parameters," it argued.
Whereas switching off at 2,789 feet above sea level may seem connected to the fact that the highest testing ground in Europe is found at 2,165 feet, Opel said this in reality was designed to prevent excessive sooting as oxygen levels in the air decrease the farther up a car travels. Other reasons were to stop ammonia from seeping out into the air, which occurs when too much urea is injected into the after-treatment system.
Industry executives appear increasingly sensitive when it comes to this hot-button topic. Either they risk coming across as if they are concealing information from the public or they end up sounding like they want to cow critics into submission by bombarding them with technical details, such as citing 17,000 parameters.
The CEO of a German services provider that specializes in engine testing, emissions and development said talking on the record amid such a charged atmosphere was the political equivalent of voluntarily walking straight into a "minefield."