View Single Post
  #9   Report Post  
Posted to rec.crafts.metalworking
Carl Ijames[_10_] Carl Ijames[_10_] is offline
external usenet poster
 
Posts: 41
Default Clare. Fuel amount per injector firing?

wrote in message ...

On Mon, 09 Jan 2017 16:51:17 -0600, Tim Wescott
wrote:

On Mon, 09 Jan 2017 12:27:25 -0800, etpm wrote:

Greetings Clare,
I just thought a few minutes ago how a fuel injector might be a good way
to apply Minimum Quantity Lubrication to cutting tools. I figure you or
someone else here must know what the minimum amount of fuel is that can
be delivered from a typical gasoline engine fuel injector. Gasoline is
thinner than the MQL fluids but maybe the injector would work anyway.
The thinnest MQL fluids I use are water thin or pretty close to water
thin. The thickest has a viscosity camparable to or slightly less than 5
weight motor oil. Actually less than 5 weight. Maybe 5 weight and
kerosene mixed 1/2 and 1/2. I can certainly pressurize a liquid
reservoir to the required pressure. Maybe a trip to the wrecking yard
for a ruel pump and some injectors is in my future.
Thanks,
Eric


I'm not Claire, or necessarily even competent. But I can pull numbers
out of my ass and do math on them:

60MPH / 30MPG = 2 gallons/hour

3000 RPM = 50 rev/sec. Assume a 4-cylinder, so 100 squirts/second

(2 gal/hr) * (1hr / (3600sec)) / (100 squirt/second) = 5.6 x 10^-6
gallons/squirt.

(5.6 x 10^-6 gal/squirt) * (128 ounce/gal) = 700 x 10^-6 ounce/squirt.

(700 x 10^-6 oz/squirt) * (30 cc/oz) = 0.02 cc/squirt.

This help? Higher viscosity means that the fluid delivery will be -- uh
-- less. Worse, higher viscosity may mean that you're screwed if you're
looking for a particular spray pattern. If electronic fuel injection is
a thing in diesels, maybe use an injector from one of them?

Greetings Tim,
I wish you would pull those numbers from somewhere else. Even your
nose would be better. Nevertheless I held my nose and used some of the
first numbers you pulled out of your ass: gallons per hour. I then
converted those numbers to cubic centimeters. Then did similar
calculations to yours and arrived at the same number you did. Thanks
for making me look too lazy to figure out how much fuel is squirted.
..02 cc might be just about what I need. If too much I could lower the
delivery pressure. The spray pattern may not be perfect but I can
modify that if need be with a nozzle downstream from the injector. Or
I can just use the injector as a timed metering valve upstream from
whatever nozzle. Cool.
Cheers,
Eric
================================================== ==============

There are injectors that deliver a hollow cone, a single stream centered on
axis (made by Lucas), three streams in a cone shape, a single stream angled
to the axis, and I'm sure others. Excluding throttle body injectors which I
know little about, they all seem to have a minimum pulse width of about 1
msec and are roughly linear from there up to about 85-90% on duty cycle.
Above that they get erratic but if you just turn them on you should get the
rated flow rate. The hollow cone spray patterns usually use a single pintle
with a conical shape, while the stream injectors use a disc. The disc can
open quicker but the solid stream doesn't evaporate as well so I don't think
they are very popular any more. Way back I ran Lucas 5208008 injectors in
my car, single stream disc, rated at 40 lb/hr at the time although Stan
Weiss's great table has them as 37 lb/hr or 392 cc/min at 43.5 psi (3 bar),
see: http://www.users.interport.net/s/r/s...eifc.htm#LUCAS. Just
for grins, 392 cc/min * 1 min/60 sec * 1 sec/1000 msec * 1 msec = .0065 cc
in one 1 msec squirt, in the same ballpark as Tim's estimate.

-----
Regards,
Carl Ijames