Clean diesel?

Volkswagen has been cited for fixing the computer algorithms so it gets full NOx control only during emissions tests.  From the EPA and CARB websites. One of the early truck engine emissions standards said the engine had to pass under a given set of conditions but didn’t say anything about other conditions.  The engine manufacturers got to send free will gifts and offerings to the government for precisely following the regulation.  This one will be interesting.


8 responses to “Clean diesel?

  1. Of course it is impossible to simulate all the conditions a vehicle will operate under……Putting your foot down will guarantee rich mixture unless you want practically zero acceleration………..

    • Actually, that would be good for NOx. Diesels operate on a 100% stoichiometric air, so at full output the exhaust O2 should be around 10.5%. Stomping on the accelerator dumps extra fuel through the injectors and results in unburned, partially burned fuel, so you get lots of black smoke and particulate. That’s a cooler combustion temperature and lower NOx. Of course the oxycat is glowing due to all the VOC, fuel and carbon particulate hitting the catalyst. And the diesel particulate filter is going nuts.

      I suspect they retard the injector timing for the test (NOx down and CO up before catalyst), and do a full urea feed to the SCR. In the non-test mode, the timing comes back to normal and the urea feed drops off. Just speculation,the Wolfsburg gearheads are much brighter than I.

  2. Lucifer Morningstar

    Stupid rules INVITE people to game the system. The EPA said you have to get a lot of miles in cars, So no more big cars, Death of the station wagon. But no limit on what light trucks, So SUV’s are in. Look at the 55 mph speed limit. (Do you remember what the 55 mph limit was suppose to accomplish? 😉

    • They’re called market distortions. And it’s the reason that, for example, you can’t bring in a euro spec diesel that gets, say, 70 miles per gallon at speed and actually pollutes less measured on a *per-mile* rather than per gallon basis. basis than a similar American spec engine. (Or why California gas, with its “Special Blends” costs at least a buck more than anyplace else, courtesy of the CARB, disconnected Watermelons and the Oligopolistic Refiners.)

      Since diesels are most efficient when running around 24rpm/24in, they absolutely lend themselves to series hybrids where the engine would serve as nothing more than a generator for the battery bank. .As pointed out above, since the diesel is now constant speed, you could then easily game the timing to achieve whatever reasonable pollution levels desired, minus the complaints and finger pointing. Add to that the fact that low/zero sulfur diesel can easily be made from natural gas – a few cents price delta vs that from petroleum, a difference people willingly pay since the engine runs better with less problems –
      you then have a winning personal transport formula since (a) there is no shortage of natural gas in North American, and (b) the need to import petroleum from elsewhere is reduced considerably, helping both trade balance and negating foreign entanglements.

      OK, all that’s kinda wordy and run-on, but reality is that Volkswagen gamed the system, something all companies do in the face of regulations, got called out on it by an agency looking to validate itself – Is it budget time? – and now there’s much hyperventilating, clutching of breasts and rolling of eyes as the various *aggrieved* parties try to outdo each other with their grandstanding.

      Just a thought.


  3. a quick note VicB3 why bother with a batterybank???? Diesel-electric powerplants still are the most efficient and reliable systems… I really don’t understand this ‘need’ for a load of heavy/expensive/dangerous batteries

    • Because I want to keep the diesel generator at a constant RPM, thus avoiding the ups and down that generate the most pollution. Bear in mind that another word for battery is “accumulator,” .and it’s the electrical equivalent of a water tank that delivers fluids at different rates as needed – amperage – yet takes in water at a steady rate – the generator -then shuts off the incoming flow because it’s full.

      If you research the newer diesel electiricl locomotives, you’ll discover that they’re all hybrids for reasons of both fuel economy and pollution.
      G.E. Evolution Series of locomotives would be an example of these.

      Also, batteries needn’t by either large of heavy. Rather, just enough to store the power and deliver it in sufficient quantities when needed. A Chevy Volt would be an example of this. Plus the technology is advancing at a rapid clip. Research both super-capacitors and graphenes to see what I mean.

      I’m not anti-car by any means. It’s probably the most efficient means of high-speed personal travel out there, emphasis on the word “Personal” (Read E. Bruce Briggs ‘The War Against The Automobile’ to see what I mean.) But once you’ve get yourself away from the Otto Cycle and geared mechanical transmissions, a whole new world of possibilities opens up.

      Hope this helps.

      Just a thought.


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