Tuesday 22 September 2015

VW TDi rigging: —but why?

The VW TDi rigging story is pretty serious; it's the third big automotive software disaster —and we haven't even covered disasters #1 and #2 yet.

Which are, for reference:

  1. Toyota's dev team being utterly incapable of writing software in accordance with modern software development practices  —with the failing accelerators being only one of the consequences of this. None of those people should ever be allowed to write code for anything more safety critical than a flash-based web advert ever again.
  2. Jeep's "Jeep Cherokee online edition", feature, where every model shipped in 2015 had a modem scannable on the network, an 0wnable infotainment console and an engine (on the same single network), whose network stack never once questioned why the mp3 player was sending messages to the transmission to turn itself off. Those engineers shouldn't be allowed to code for anything directly or indirectly attached to the Internet —which, in modern society, means they can't even code a light bulb any more (do watch that entire video for terrifyingly accurate summary of the current infosec world).
  3. VW's US TDi models detecting when they are pushed through their emissions control exam and so not being polluting for the hour or so it takes. (this would be good for MoTs actually; it would go down well with our business plan to rent VW wingmirrors for MoT tests)

Now, one of our team members does own an (ageing) VW TDi barge, and while it is frugal —even at 20 mph, we add—, it has some limitations, specifically it is a lot less responsive than the VW Passat 1.8T "wagon" which used live in the double garage up in the Pacific North West. That car had a ski box in the roof, Z-chain snow chains in the back and the ability to make it from that garage over the mountains and into in he car park of the ski resort in 2h30, —all for less than $20 of "gasoline".

Because that is the surprising thing about the US adoption of turbo-diesels: from an EU perspective, the US give away free fuel to their citizens.

Being evidence driven, here is our evidence, a receipt from ten-days into the Bristol-Traffic-strategic-meetup-with-the bay area self-driving-car/police state manufacturers. Driving, for reference a VW Jetta 2.0 16v petrol engine with automatic transmission rented for $250/week.

This is for seven days worth of commuting across mountain view, 30 miles a day,  plus the weekend leisure activities silicon valley is famous for (going to shopping malls and buying new apple hardware in the belief it will make your life more satisfying).

Assuming 150 miles over the weekend plus the commute, 30x7 + 150 = 360 miles.
The receipt is for ~13 US gallons, 27 mpg. In UK Gallons, that's 32.7 mpg. Not bad.

Now look at the total cost, $44.32 —that's £28.63. For 11 UK gallons. Which is £2.65/gallon —or, more tangibly, 58 pence a litre.

58 pence/litre? And people think the fuel economy of that car was so bad that they had to switch to a TDi model with higher economy. That is, they felt "gas" was so expensive that they had to pay a premium for an engine with more cabin noise, bounces up and down more when you are trying to text at traffic lights and whose overtaking ability, once you consider the gear-drop and turbocharger spinup will only take place once you actually hit the accelerate pedal, isn't actually that good. In contrast, a petrol Jetta is, compared to a UK petrol-engined Golf, half the price per mile and equally nimble, albeit somewhat crippled by its saloon-car design preventing it being so good for throwing things in the back or for parking in smaller spaces. You would have to be doing a lot of long-distance driving to actually justify swapping the petrol engine for the diesel turbine.

That's what VW managed to pull off with their software: not the rigging of the emissions —but the convincing of the US customer that they'd actually have a better time in a Turbo Diesel.

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