Oh yes, the old 'Its only cheating if you get caught' argument. That tends to not work too well in real life.Cold Fussion wrote:
Is it really cheating? It passes the EPA emissions tests, it's really a failure of the EPA to do representative testing.
From what I understand, the software recognised that the car was being tested and it made changes to the pollution control systems to ensure that it was inside the mandated range. The only time it actually runs in that range is when the software recognises that the test is being performed.
I worked on engine management software many years ago. To me it seems logical that the software could this. The big reason though is 'why'.“Put simply, these cars contained software that turns off emissions controls when driving normally and turns them on when the car is undergoing an emissions test,” Cynthia Giles, an EPA enforcement officer said. “We intend to hold Volkswagen responsible.
It is generally recognised that most diesel engines produce a large amount of particulates, these need to be scrubbed by emission control systems before the exhaust gasses are permitted to leave the car. It is not that simple, but bear with me.
There are numerous strategies to accomplish this. Some form of NOx reduction is needed within the emissions control systems. Mercedes use a system called Blutec. Initially VW used the same technology, licensed from Daimler. But in 2007, they broke away from using it as they did not want to be associated with using a competitors tech.
Blutec (or AdBlue) is a 'selective catalytic reduction' system that uses urea (or ammonia) injection into the catalyst to reduce the NOx content of the exhaust gasses. This is not a cheap system, it needs a urea storage (and refill /monitoring) system, a very expensive catalyst and plenty of software and hardware integrated into the car.
The other option, which VW rolled out in 2008 is called a NOx adsorber. It is a version of a catalytic convertor that is capable of trapping NOx and dealing with high O2 content in the exhaust gasses. This is combined with heavy exhaust gas recirculation and in theory at least it should be pretty good. It is very tricky to get right, but it is possible.
Except. You need to run extremely lean, the EGR system is prone to choking and the catalyst is very, very temperature sensitive. All of this combined means that while it will work sometimes, long term operation is perhaps suspect.
Of the two technologies, urea injection into the catalyst is more reliable, but there is a lot of hardware there and you need to ensure that the vehicle has urea in the tank at all times. The tank takes up space, there is a licensing cost with Bluetec/AdBlue and the software changes need to accommodate this.
As best I can see, VW will have to tread very carefully.
The cars that are effected may be retrofitted with urea tanks and catalyst injection systems and somehow re-certified.
Maybe software will bring them into compliance, but almost certainly at the expense of fuel economy or longterm viability with the EGR issues that already exist.
Or they simply crush the lot and replace them with nice, shiny new ones......
I was trying to figure out exactly which engine it is and I failed, mostly because the engines are often four letters, e.g. CAYC (1.6 TDI) or CFHC (2.0 TDI), both of which are part of the EA189 family.