Date:         Thu, 8 Sep 2005 16:44:10 -0700
Reply-To:     John Bange <jbange@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Bange <jbange@GMAIL.COM>
Subject:      Re: alternative carburetion of FI 2.0 Liter vanagon engine???
In-Reply-To:  <43208796.5030901@charmfx.com>
Content-Type: text/plain; charset=ISO-8859-1

> Mostly I'm thinking those with machinist skills may attempt to build
> versions of devices from patent drawings to establish if the thing works
> or not...a small one for a lawn mower, say.


Usually an understanding of the laws of physics is enough to tell whether a 
device will work or not. Any halfway decent mechanical engineer can figure 
it out in a few minutes without building one. 

...most seem to depend on vacuum, metering and/or use of heat to
> encourage a more thorough dispersion of fuel as vapor or near
> vapor...more surface area on the molecules results in cleaner burning
> with less fuel.


Dispersion is most dependent on combustion chamber geometry, followed by 
injector design. But losses due to dispersion in any modern engine are 
actually quite minimal. Large gains are really only to be had by reducing 
energy loss elsewhere.

I say that but don't necessarily believe the legends of 100-200 mpg
> carburetors. It does seem that even a 10%-20% improvement might be
> worth looking at the ideas though.


A 10-20% gain would be considered incredibly good and, were it to be had by 
implementing easy patent devices, would have been adopted long ago. There 
are plenty of ways of getting 15% or so-- the Miller cycle engine comes to 
mind-- but they're not in the form of a "turbonator" plate you bolt on to 
your throttle body.

There are engine designs which are acknowledged to be more efficient and
> are being used in some vehicle applications. I found a reference to a
> Stirling engine design being used in Swedish subs.


Economy comes at the price of inflexibility. You can't really "throttle" a 
Stirling engine-- they pretty much run within a narrow optimal RPM band. 
Great if you're using it to spin a large generator (sub), not so great 
operating a direct mechanical drive (car). 

neither really exploiting the promise offered by either the vapor
> induction or extremely precise fuel metering systems mentioned in the
> legends of such devices....but they do work and other than injectors and
> jets getting clogged aren't problematic.
> 
> An idea I've toyed with is finding a mechanism to limit the time the
> injector is open and increase dispersion out of the injector effectively
> reducing the amount of fuel but increasing the surface area of the
> amount injected. In computer controlled injection a method for
> adjusting the mixture from the specification would be needed since these
> settings and those controlling air are in the EPROM.
> 
> I've seen custom computer control setups to replace factory vehicle
> computers...they provide the ability to make such adjustments.


Thing is, there's not all that much room for improvement on such a stock 
engine in the arena of fuel dispersion. So much of that is dependent upon 
injector design and combustion chamber geometry during the compression 
"squish" that twiddling with injection firing timing is really little more 
than doorknob polish.

What I have noted is that when you mention these legendary devices often
> folks point to the debunking web sites and say they are all shams.


'cause they are.

I personally remember seeing 2 guys testifying before Congress on C-Span
> in the late 70's when they had gas/efficiency hearings about a tweaked
> diesel they put into a Pinto body that they got 98 mpg out of. Their
> testimony was interrupted by a phone call from a representative of a
> major manufacturer and I never saw the story on any other media.
> 

Sounds unlikely. Not so much the tweaked car part, because you could easily 
make a super-efficient lightweight vehicle that gets 98 mpg, part of the 
trick being that it doesn't go over 30mph or so and takes 3 minutes to 
accelerate; but the part about the manufacturing rep calling to interrupt a 
congressional hearing and them announcing that on CSPAN! A congressman 
taking aphone call during a hearing on TV?
Being that such a thing happening during a congressional hearing would be 
unprecedented and CERTAINLY not ignored by the media, I think you're maybe 
confusing several different things: the congressional hearings on fuel 
economy, and hearings on the safety of the Pinto, both in '74 (six years 
before CSPAN existed); true stories about people like Tony Capanna, who 
converted Darts and Pintos to diesel in the 70's, getting up to 50mpg on the 
Pinto; and the apocryphal tales of 300mpg carburetors that are 
"accidentally" sold, then "mysteriously" turn back into 15mpg carburetors 
after the first dealer servicing.

Information has a habit of "escaping". One way or another, be it through 
leaks or through independent rediscovery, there's no possible way to keep 
tremendous breakthroughs secret. I understand the desire to believe 
conspiracies. It's just human nature. We are uncomfortable with the idea of 
problems without solid solutions. The problem of improving fuel efficiency 
is incredibly complex, requiring years of engineering/science education 
before one can even BEGIN to make sense of the pitfalls and subtleties 
current cutting-edge techniques are dealing with. Faced with such a 
situation, people "on the sidelines" feel utterly helpless-- there's no one 
they can petition to change the laws of physics. When they hear a story 
about the 300mpg carb, though, they latch onto it. HERE'S something they 
understand! The problem has ALREADY BEEN SOLVED-- it's just the collusion of 
"the industry" keeping it SECRET. This gives them something to vent their 
frustration against. 
The auto industry hasn't helped itself any, what with its history of doing 
things like teaming up with the oil industry and buying up the Red Car Line 
in Los Angeles, dismantling it to get people to buy more cars back in the 
early days of the industry. Other things, like Ford refusing to spend the 
$11 necessary to put a rubber liner in the Pinto gas tank to keep it from 
burning people alive in accidents because it was cheaper to pay off the 
deaths than recall all those Pintos, didn't help their image either. These 
things, though, are the extreme cases of blatant mustache-twirling 
dastardliness and outright pigheaded cost-benefit analysis. But the fuel 
economy thing? There's just no sense to it. A car manufacturer that had sole 
rights to the 300mpg carb? They could RULE THE INDUSTRY. 
Really, it all comes down to simple physics. The VW Lupo 3L wrings about 
75mpg, but it's a tiny lightweight car with a sophisticated 3 cylinder TDI 
engine. This is the way you get economy. There's no silver bullet. There's 
no easy way out. Just hard work.