Fast indepth look at the VW smog cheat news

#hashtags: #Tier 2 #EPA

The company faced a challenge: In 2008, all diesel-powered cars sold in the U.S. had to meet to significantly stricter emissions standards that were a part of so-called “Tier 2” regulations. The EPA was looking to rid diesel of its sooty, noxious ways.The company creatively wrote software that would recognize when the car was undergoing an emissions test, a potentially complex algorithm that might incorporate everything from differences in front and rear wheel speeds to variations in steering inputs and even barometric pressure when the car is being tested by the EPA and changes its performance to meet emissions standards.The rest of the time, the cars produce up to 40 times the legal limit of nitrogen oxides (NOx) To reduce NOx emissions, there are two main approaches. One is selective catalytic reduction, or SCR, which involves injecting urea into the exhaust stream to react with NOx and turn it into harmless nitrogen and oxygen. The approach is incredibly effective, but it requires an additional tank to store the urea, a heater to keep it fluid, a pump, a valve, a mixer, and a catalyst to speed the reaction. Despite that, most automakers ended up settling on SCR, in part because it worked so well. Side note, to reduce air pollution, they create plastic garbage with all the containers of urea fluidBut on smaller cars like the Volkswagen Golf and Jetta, SCR is less than ideal. There’s not a lot of room to put the urea tank, pump, and other equipment, and price-conscious consumers may balk at the added expense, which costs the manufacturer about $50 more for a 2.0-liter engine than the alternative, according to a study by ICCT. That equates to a cost savings of over $500 million over 11 million cars. Volkswagen engineers were hard at work on the alternative based on Toyota research from the mid-1990s, a NOx storage catalytic converter (LNT). LNT uses a catalyst to absorb and store NOx so it doesn’t escape into the atmosphere. When the catalytic converter is full, the system burns off the stored NOx by pumping an extra burst of fuel into the cylinders, most of which passes through to the converter where it burns the NOx into harmless nitrogen and oxygen. 2008, the 2009 Jetta TDI was named Green Car of the Year by the Green Car Journal. This year, named the 2015 Passat TDI its “Eco-friendly Car of the Year.” These cars were green for the budget, green for the environment. Once the sting of the lie fades, the US customers who bought 482,000 of those cars will feel the real pain. Because Volkswagen will be forced to recall those vehicles and somehow make them to meet federal standards. There are two apparent ways to do that, and owners who value performance, fuel economy, and trunk space won’t like either. One is to “reflash” the engine control module, recalibrating the software so the car always runs the way it does during EPA testing, and always meets emission standards. The downside here is that to achieve the drastic drop in NOx emissions, the cars in test mode sacrificed some fuel economy, or performance. Just how much is hard to say, but any drop in torque—one great thing about diesels is how they accelerate off the line—will not make drivers happy. And a drop in mileage would likely cost VW, since hundreds of thousands of drivers would have to spend more on fuel than VW promised at the time of sale.