On Sep 27, 1:02 am, Jon Elson wrote:
Robert Swinney wrote:
Now that this inane and totally ridiculous thread has been opened, I wonder how long it'll be before
we get around to the 100 mpg carburetor -- you know the one the oil companies have been squashing
since the 1920's. Oh! Wait -- I think I saw some on ebay just the other day.

Actually, if you get rid of the throttle, and control the engine
by varying the fuel flow, you can get a decent increase in
efficiency - by reducing pumping loss to zero. Oh, but there
are some problems -- mostly getting gasoling to not knock.
And, BOY, when it runs quite lean, it can REALLY knock.

My family's ram van with the 5.9 L V-8 had a momentary computer
malfunction of some sort (I'm guessing) once while climbing a
long hill, and it suddenly knocked so hard I thought it had
thrown a rod. I let up on the gas immediately, expecting the
engine to seize on the spot, but it didn't, and never did that
again. Didn't even turn on the check engine light. My guess is
some register in the fuel metering PWM circuits got loaded with
a wrong value, and one cylinder was only getting splash from the
nearby injectors, or something. But, those were the biggest
knocks I'd ever heard a gas engine produce.

I've always wanted to try building a stratified-charge gas
engine, just to see what sort of fuel economy it could provide.
Probably no better than a mediocre Diesel, though.

Jon

I had a 1978 Honda Accord with a CVCC prechamber stratified-charge
engine. It gave 36-38MPG in the summer, 30-32 in the winter, and up to
44 on a long trip; NH to VA on one tank. Interior space and comfort
were almost identical to 2 friends' Saab 900s, handling was a little
better. I think it was the last car to pass emissions without a
catalytic converter. It got around 70HP from 1.6L, which was fine
around town in NH but not really great on the Interstate in MA where
traffic is fast, heavy and aggressive. I gave it up for a 4WD pickup
truck with an NRA sticker on the back, which got considerably more
respect even though it wasn't much faster (2.3L engine, 28MPG).

Jim Wilkins