Volkswagon TDI (turbocharged direct injection) scandal

Sardonicus said:

It's a hoax.  Inhofe found snow.

“You can believe NASA and you can believe what their satellites measure on the planet, or you can believe the Senator with the snowball. The United States Navy takes this very seriously, to the point where Admiral Locklear, who is the head of the Pacific Command, has said that climate change is the biggest threat that we face in the Pacific…you can either believe the United States Navy or you can believe the Senator with the snowball…every major American scientific society has put itself on record, many of them a decade ago, that climate change is deadly real. They measure it, they see it, they know why it happens. The predictions correlate with what we see as they increasingly come true. And the fundamental principles, that it is derived from carbon pollution, which comes from burning fossil fuels, are beyond legitimate dispute…so you can believe every single major American scientific society, or you can believe the Senator with the snowball.”

—Steve Mirsky

So I did a little research earlier today and here's what's going on (to the best of my recollection).

Diesel engines run most efficiently and with the most power when they're running very lean.  That means an excess of O2.  Us chemists call this an oxidizing environment.  Gasoline engines run best (most efficient with lowest emissions) in a stochiometric environment - perfect mix of fuel to air.

The problem is, with an oxidizing fuel/air mix, you get NOx - NO and NO2.  Catalytic converters don't work well with more than 1% O2 in the exhaust effluent.

So the particulates are captured by a filter, but the NOx is the problem.  Traditionally this is solved by adding urea to the exhaust...but that means you can run out of this (a liquid).  At the very least you have to maintain it and it's expensive.

In 2008 or so, they came out with an NOx trap.  This thing traps the NO and NO2, but it gets filled up.  The way to keep the excess NOx from going out the exhaust is to reduce (remove oxygen) the NOx.  To do this, you run rich (reducing) - slam it with diesel fuel (almost all organics are reductants) and with the heat > 200C, the NOx is reduced to N2 and H2O.  Clean.

Problem is, if you run rich, you use more fuel and get less power. 

So what VW did was somehow detect if the system was being monitored, probably through a back pressure monitor, and run the system rich.  Then when operating without monitoring, back off on the fuel and run lean - better power and fuel economy, but up to 40x more NOx emissions.

Germans, they think of everything.

@U_tarded

xactly *burp* (excuse me). 

That's the other avenue they could have taken.

Diesel Exhaust Fluid (DEF) is a non-hazardous solution, which is 32.5% urea and 67.5% de-ionized water. DEF is sprayed into the exhaust stream of diesel vehicles to break down dangerous NOx emissions into harmless nitrogen and water.

So my prediction on the fix is this (and I might be off-base because I don't know the capacity or the extent of the fraud from VW):

A firmware or whatever update of the ECU (engine control unit) is a fairly easy install - either a chip or a flash of EPROM on the ECU.  Whatever the mechanism, VW will have to run the engine richer. 

What you'll see is a reduction in fuel economy and torque in normal driving. 

Depending on the capacity of the NOx trap thingy, if they can maintain it with sufficient ability to capture NOx, the full power (rated HP and torque) shouldn't be impacted in short term acceleration.

The reasoning I have is the fuel air mix can be rich enough to keep the trap fairly unsaturated with NOx.  To develop full power when flooring the pedal, the ECU can run lean and the cost is filling up the trap quick.  But there will be a maximum time for this before power falls off.  They can compensate in cycles by dumping fuel in the trap (if it's hot enough otherwise you get hydrocarbon emissions) and expedite reducing the NOx.

Anyway, what I'm saying is it isn't the end of the world.  You'll still get where you're going, probably a little money in your pocket from one of the many class action lawsuits, and you'll get the rated HP if conditions are right, on demand.

What I've noticed is VW drivers, especially jetta drivers behave as if they're in Porches.  They drive more ass-hole-y than the average driver.  I respect that, being a sporty driver.  But they can't do it as much, and they'll have less miles between fill-ups. 

Now, a pause, for schadenfreude...... there.   done.

Worst case is you don't get the recall fix because you don't want to give up the good mileage and performance.   There's a possibility there's a lot of people that bought the cars because of the performance/good mpg combo that don't give a F about the environment.  Well, I can see a that car being declared as a salvage title until that update is made.  Which means you can sell it (depending on state) but you can't put full coverage on it.  That would reduce the value of your car.  Queue more class-action lawsuits. Wait, there are at least 25 in the works right now.

Sleep tight my friends!

@buzd504 I'm totally with you alignment wise.   This is all early stage prognostication.  So I want to make sure everyone knows I'm on a BBQ forum full of idiots and I'm one of them saying stupid stuff.

First of all, are you in on Brisket Camp?  Your car should make it there, if not I will send a rescue vehicle to airlift you via helicopter to the venue.  Second, you passat drivers are always buzzing my ass as I do 95 MPH on I-10.  For f*cks christ, I'm just having fun.  (I'm kidding here) (edit - not really).  I passed up a state cop on the access road today doing 90 and he didn't pull me over.  I'm blessed apparently, not getting a ticket although I should have received at least a thousand of them in the last year.

Yada yada..we all have fun...I don't like to drive a Yugo. 

Give me a PM if you're making it to camp.  Sorry if you already told me, I'm totally dyslexic.  We're gonna make this like 1999.

Also F-little stephan.

Then end.

(drops mic)

Owww.  my foot