Sunday, October 11, 2015


By Pepper Bowen

Back in the 90s, German manufacturer Volkswagen (VW) used the “Fahrvergn├╝gen” ad slogan to set their brand apart by touting the enjoyment that comes from driving a VW. This was intended to create a new mental association for VW cars with consumers as not just the source of billowing clouds of diesel smoke emanating from their tailpipes.  VW introduced clean burning and environmentally friendly biodiesel and positioned itself for the new millennium to further expand their sales and profit margins.

That was until the scandal broke.

The 2009 through 2014 VWs have recently become the focus of EPA investigation. VW said originally that the disparity between EU and US emissions standards caused a variance in emissions results. So the International Council on Clean Transportation (ICCT) stepped up and ran their own tests intended to prove that diesel is clean and safe in the US and up to emissions standards.

Apparently surprised to learn that the reported VW emissions did not comport with their own findings, they partnered with West Virginia University’s Center for Alternative Fuels, Engines and Emissions for more accurate testing. So between 2013 and 2014, the collaboration undertook a project aimed to evaluate real-world operating emissions from light-duty diesel vehicles in the US: a VW Jetta, a VW Passat, and a BMW X5.

ICCT reports their results were as follows:
  • Real-world nitrogen oxide (NOx) emissions from the Jetta exceeded the US-EPA Tier2-Bin5 (at full useful life) standard by 15 to 35 times.
  • For the Passat, real-world NOx emissions were 5 to 20 times the standard.
  • The BMW vehicle was generally at or below the standard, and only exceeded it during rural uphill operating conditions. 

That sounds pretty bad so now a little bit of clarity.

EPA’s Clean Air Act establishes air quality standards, national ambient air quality standards (NAAQS), for both stationary and mobile sources. The emissions standard for new cars is emissions of hydrocarbons, carbon monoxide, and nitrogen oxide 0.25, 3.4, and 1 gram per mile (GPM) respectively. Though these seem like really low numbers in and of themselves, their impact is quite large.

EPA uses a calculation based on average fuel economy of 21.6 miles per gallon, 11,400 miles driven per year, and the standard of one million grams per metric ton in order to arrive at the average tailpipe annual emissions. Look to this example from the Greenhouse Gas Emissions white paper:

                                        CO2 per gallon                 8,887
Annual CO2 emissions = ------------------ x miles =  ------- = 11,400 = 4.7 metric tons Carbon Dioxide
                                          MPG                               21.6

From there, the EPA used that result to compare another source to emissions from passenger vehicles. It is through this comparison that the global warming potential of a gas can be determined. Carbon dioxide is the control and its global warming potential (GWP) is established at 1. Nitrous oxide has a GWP of 298 which is in comparison to that of carbon dioxide. However, the interesting thing about nitrous oxide is that the value is completely dependent upon the design of the engine and the emission control system in the vehicle as opposed to the fuel consumption per mile.

Now that it’s a little easier to see the true impact of the ICCT test results being substantially higher than the EPA standards, back to Volkswagen…

As it turns out, the disparity in standards between the EU and the US was never really the problem. Volkswagen had installed both “road calibration” and a “switch” which are auxiliary emission control devices (AECDs). AECDs are by definition intended to “[reduce] the effectiveness of the emission control system under conditions which may be reasonably expected to be encountered in normal vehicle operation and use. Since VW’s “road calibration” and “switch” are AECDs that were neither described nor justified on the COC applications, they are illegal defeat devices. Long story short, vehicles equipped with defeat devices cannot be certified.

In the end, VW admitted “it had designed and installed a defeat device in the vehicles in the form of a sophisticated software algorithm that detected when a vehicle was undergoing emissions testing.” So in a Notice of Violation (NOV) to Volkswagen, the EPA communicated its determination that “VW manufactured and installed defeat devices in certain model years 2009 through 2015 diesel light-duty vehicles… These defeat devices bypass, defeat, or render inoperative elements of the vehicles’ emission control system that exist to comply with CAA emission standards.” The emissions standards are there in part “to protect and enhance the quality of the Nation’s air resources so as to promote the public health and welfare and the productive capacity of its population,” and “to initiate and accelerate a national research and development program to achieve the prevention and control of air pollution.”

Both the EPA and the California Air Resources Board (CARB) have levied hefty citations on the company. The CEO has stepped down in the wake of the scandal and the recall will likely cost millions of dollars. In light of all this, consumers may not experience the fun of driving VWs for a while.

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