My wife and an iPad mini

PRR said:

> without adding additional components a simple software fix can only force to run like it does in test mode all the time

No, they can re-program any limit between Test and Pep. (Assuming time to re-think the situation; also government OK for the new calibration, which in this case may want to be rushed-out before a formal test cycle.)

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I am on thin ice arguing this hypothetical, (I don't know for a fact) it seems if they could deliver the performance and mileage, and clean emissions from just software tweaks, they would have in the years since they started cheating. I can't imagine anybody considering the cheat a long term solution.

On my 1967, to increase power (and smoke), I would take the pump apart and remove some shims that set the maximum stroke of the metering piston. To increase total power I would put lighter springs on the governor weights to raise the limit speed from 2,150RPM to a blazing 2,500RPM. (It's the same bore/stroke as a 400CID V-8, it ought to live that fast, if not for 5,700 hours.)

Some other effects. The "best" (clear exhaust) fuel quantity is set hot. When cold, this much fuel smokes like a tire-fire. (Also because with this many hours, compression is down, it really hates to light-off when cold.) This engine has no idea if it is warm or not; a computer surely would, and would give less fuel when the chambers are cold. This is more of an issue on Diesel than on spark: the Diesel needs chamber heat to ignite without stressfully high compression, and an idling Diesel will go much colder than an idle spark engine because of fuel-control and large expansion ratio. (I can idle 20 minutes and lay my hand on the block.)

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My brother, the smart one, worked in turbine nozzle design, and he tells me that the aircraft turbines very specifically engineer the particle size in the jet exhaust so the smoke "looks" clear. Larger particle size makes the same exhaust visible and appear dirtier.

I don't know if automobile engines have similar control over the combustion process, but they surely manage visible smoke for perception reasons. 

While my 1967 Diesel is only stops and cams (no electricity needed to run), a modern Diesel is *totally* under control of its computer. Fuel quantity and timing have the most effect. The rate-of-change of these parameters with change of "throttle" pedal position affects perceived "pep".

Many of these Diesel sedans probably feature a turbo with a blow-off, again under computer control. While sane use of a blower will improve efficiency and probably reduce smog, any tractor-pull contest shows that over-blowing and over-injecting can smog-out a stadium.

There are secondary smog treatments, similar to spark-engine catalytic converters. But I bet these bits were installed so they would function in Test mode. I have not looked at (could not keep up with) recent "advances" in Diesel smog control, but I doubt they cause large loss of power. They may have heaters and squirters and such, which would be under computer control.

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One technique is urea (yes piss) injection. If they already had this hardware in place, why turn it off?

from link said:

As soon as possible, VW says, it will start equipping all its diesel cars in Europe and North America with AdBlue technology and selective catalytic reduction, a chemical process that breaks smoggy NOx down into nitrogen and water. It adds complication and expense—$5,000 to $8,000 per car—but it’s effective, eliminating 70 to 90 percent of NOx emissions.

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  http://www.wired.com/2015/10/vw-plans-to-recover-from-its-scandal-by-going-electric/
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I am repeating myself, but best fix IMO is to not fix these models at all but negotiate a trade with the regulators to reduce an equivalent amount of emissions elsewhere... Of course their future new cars must pass all standards.

JR

[edit] just saw a newspaper story talking about Audi motors involved too. This article say the Euro zone fix is a software changes and minor intake modification to improve intake mixing. The article says this is not adequate for the US market.  [/edit]

JohnRoberts said:

One technique is urea (yes piss) injection. If they already had this hardware in place, why turn it off?

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That's the thing -- the affected VW models (including our TDI SportWagen) don't have a urea injection system. That's what made the car relatively inexpensive.

When the band does shows, we rent a Mercedes Sprinter van, diesel of course. Loaded with gear and people, the thing got 17 mpg on a run from NJ to Cambridge and back. An Econoline pulling a trailer couldn't possibly meet that. Anyway, I looked through the rental agreement, and there was a section about maintenance, which said that every 10,000 miles the vehicle required dealer service. The rental company paid for the service, but a band on a two- or three- month tour would have to plan on a service day. Part of the service was to refill the urea tank.

> every 10,000 miles the vehicle required dealer service

Presumably they'd want you to change the oil about that time. So a bye-day anyway.

I think the urea tank was sized to line-up with oil change intervals.

BTW: Diesel Fluid is readily available in truck shops. You can put it in yourself. AFAICT it is all blended to a Bosch formula; though you should probably check approval numbers just in case. And I don't know the warranty implications of topping it off without dealer or mechanic verification.

> the affected VW models ...don't have a urea injection system

That's what I was coming to. And apparently Bosch (the urea-injection inventor) knew VW was not buying uera-systems on these cars.

The system apparently works but is tricky. The fluid is corrosive, somewhat bulky, and can FREEZE. I don't know what insulation or heat or expansion-space is used to control freeze damage. It does not sound like something which can reasonably be retro-fitted to an existing no-urea design, maybe not even the unsold cars at the VW factory.

The rate of injection is tricky. Too little hardly does any good- they coat the catalyst beads with a hyper-thin layer, and any dry-spots let the NOx right through. You do not want too much, partly for user resistance to fluid consumption, and mainly because excess smells like sour pee. As NOx production is very dynamic with peak chamber temperature, it "spikes" as was seen by the guy who noticed that this model had a problem not reported by the ECU. The urea controller has to react quickly yet very accurately.

I *guess* what the test mode does is gag the engine to limit peak combustion temperature. Mash the pedal 100%, ECU sees this will lead to an NOx condition, ignores your foot and only gives 85%. (It may help that mash-pedal is not usually tested, and the tester does not know how the car should go when mashed-pedal.) This is liable to take the high parts out of the car's pep.

Some say that VW does not think NOx is a big deal. I was in L.A. around 1960 and we felt the acid-like effects of smog were at least as bad as the hydrocarbon haze. NOx control has not been strongly argued in the US, which suggests that even the experts at the US auto companies accept that it is bad.

> there is no way you can get the @ key to work !!!!!  This is essential for email addresses so why would they foul up there?

I'll just toss this in here......

"Raymond Tomlinson, the inventor of modern email and selector of the @ symbol, has died..."

http://www.mercurynews.com/breaking-news/ci_29604069/inventor-modern-email-ray-tomlinson-dies

Many people were messing with email as unfunded projects. Ray's life was much more than "@". But clearly whatever meta-character was selected, iPhone could foul it up.

Very timely on an old thread!

Out of interest, the thing eventually sorted itself out and is in regular use by 'er indoors.

Best
DaveP

FWIW; Ray was going "duh..." while sitting at a Teletype ASR33. On that wretched machine, @ was Shift-P. (No lower-case, so symbols could be loaded-up on letter keys.)

{edit} Obit by respectable journalists.