You have too much energy. Damn thorough description though. You may be
right about NOX but I don't really know too much about that, I think it is
the other emissions that are of the real political concern.
James Nazarian
71 B tourer
71 BGT V8
85 Dodge Ram
----- Original Message -----
From: James J. <m1garand@speakeasy.net>
To: <mgb-v8@autox.team.net>; bown <bown@concentric.net>
Sent: 10 March, 2003 12:19 AM
Subject: Re: Thermo 101 and Oil question
> Jim,
> While I don't know for certain (I'm a young whipper-snapper, so I
> don't remember the pre-catalyst era all that well), I think the key was
> in a previous e-mail response from Larry Hoy and a side-effect of
> carburation. The higher thermostat will ensure that the coolant will
> get up to a certain temperature more quickly. This coolant will heat up
> the intake manifold quickly which will reduce the chances of fuel
> puddling and condensing in the (previously cold) manifold and then
> dripping into the combustion chamber. Liquid fuel in the combustion
> chamber won't burn properly and will produce harmful emissions, and as a
> side note, will drip past the rings and thin out your oil on the chamber
> walls and increase the occurrence of the rings scoring the sleeves. In
> fact, that's the only reason that coolant passes through the intake
> manifold at all. So another engineering trade took place in Detroit:
> The higher thermostat set-point and hotter coolant may have
> theoretically increased the NOX byproducts of combustion, but it
> shortens the period of time that the car was running rich and producing
> very real emissions. This is why cars run cleaner after warming up. It
> is not directly related to combustion, but is an artifact of our intake
> design and the limitation of carburetors and throttle-body fuel
> injection. Multi-point fuel injection also runs cleaner after warming
> up a little, but this is because it takes a few minutes for the O2
> sensor to warm up in the exhaust stream, allowing the computer to run in
> closed-loop mode and go for that sacred stoichiometric mixture. Some O2
> sensors can heat up in a few seconds, but they don't operate over a wide
> enough set of exhaust conditions to be ideal (another trade, although
> perhaps a bad one?).
> Keep in mind that gasoline, in theory, should burn and produce
> nothing more harmful than water and carbon-dioxide. But because we
> don't give it enough time to burn completely, it produces all that other
> harmful crap. Drop a match in a puddle of gas (no, don't!.... I'm just
> making a point) and it will actually burn quite clean. Thrust a lighted
> match quickly into a tank of gas below the 'water line' and nothing will
> happen at all (saw a professor do that once.....ONCE!) But if you
> hesitate above the gasoline, the vapors go kaboom! I wonder if Prof.
> Austin is still terrorizing freshmen? Funny, I don't ever remember
> seeing him have eyebrows or arm hair....... coincidence??
> But I digress, as for your other question, I believe it is the NOX
> emissions that go up as combustion temp goes up. I think that the CO,
> and the third one (escapes my mind, what its called) go down, but I
> could be wrong on that one. Any chemists in the group?
> Ciao!
> James J.
>
> bown wrote:
>
> >James J.
> >Thanks for the excellent response. You should write text books!
> >I am curious about your comment concerning emissions.
> >
> ><James J. wrote> "I should mention that hotter temps mean higher
emissions,
> >too."
> >
> >Back in the old days it seemed like 180 F thermostats were the norm.
> >Then when emissions became an issue 192 F thermostats became common.
> >I was told that the higher temp thermostats were to help reduce
emisisons.
> >Any insight into this?
> >Regards,
> >Jim B.
///
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