[AT] Ram 3.0 liter Dieselgate

[Stephen Offiler]

Don, I am widely in agreement with essentially everything your son wrote,
with just one tiny nitpick. The urea injection systems have nothing to do
with particulates, they're for controlling NOx only.  I'd bet he knows this
and just slipped on the wording.  Particulates are handled by a completely
separate device in the exhaust system called the Diesel Particulate Filter,
a physical filter, not a chemistry experiment.

The beauty of the diesel engine is that it can run at very high cylinder
temperatures and pressures with very lean fuel mixtures.  This creates
higher thermal efficiency, simply put, more heat from the burning fuel
moves the vehicle down the road and less goes out the radiator and
exhaust.  However high temperature and pressure forces nitrogen to hook up
with oxygen, creating NOx compounds (mostly NO2, NO3, and N2O).  Can't have
it both ways, says the laws of physics.  Either reduce NOx by reducing
cylinder temperature and pressure in various ways (his choice "b")
including lower compression, lower turbo boost, greater EGR, etc... thus
creating a diesel that performs more like a gas engine; or reduce NOx using
a chemistry lab behind the engine to break apart the NOx back into harmless
N2 and O2 molecules (his choice "a")

On a separate note, thanks also to Grant Brians for lending some real-world
perspective on the reasons our government chose to control auto emissions
and the success they achieved.

SO


On Thu, Jan 12, 2017 at 9:44 PM, Don <don.bowen at earthlink.net> wrote:

> On 1/12/2017 5:45 PM, David Bruce wrote:
> > The other issue is the regs being reasonable but if they had to cheat to
> > meet the regs there is an issue. Not an insider but seems to me if one
> > was doing it others were.
>
> The following is from my son on the earlier VW scandal.  He is an
> account executive for Jaguar Land Rover and has written several books on
> automobile performance modifications.
>
> "I meant to send this to you - I sent the below response to people at my
> agency who were asking about the scandal:
>
> This goes back to the simple fact that there are only two possible ways
> for a Diesel engine to meet CA/EPA Nox and particulate emissions: a)
> Urea injection or b) Destroy performance and engine life. Choose a and
> the designers have to find a way to make the car not run when the tank
> runs dry, and risk annoying consumers who are used to low maintenance
> engines. Choose b and no one will buy your Diesel car.
>
> Here’s the list of manufacturers that chose to use Urea injection:
> Jaguar Land Rover, BMW, Mercedes, Ford, Chevy, Allison, Chrysler
> (Cummins), Volvo trucks, Audi, VW (Passat)
>
> Here’s the manufacturers that chose to go without Urea: IH/Navistar
> (almost destroyed their company when the engines failed early and had to
> be recalled), Mazda (caused them to delay/cancel launch of the Mazda6 in
> the U.S.), VW (except Passat)
>
> VW thought they could get the best of both worlds by fooling the
> regulators into thinking the cars are cleaner than they really are. ALL
> manufacturers game the EPA testing to some extent but this case is
> extremely egregious because of the difference in how the cars run. And
> of course because they got caught.
>
> Happy to chat more if anyone wants more back story – this is one of the
> reasons Diesel engines are not popular in the U.S."
>
> --
> Don Bowen       --AD0NB--
>
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