Spark plugs/injectors

[Raymond C Drouillard]

On Sat, 9 May 1998 19:10:34 +1000 (EST) danny_tb at postoffice.utas.edu.au
(Danny Barrett) writes:
>Does anyone know if it is possible to get spark plugs with fuel
injectors
>built in? I have seen one of the list members write about keeping the
intake
>pressure as close to atmospherice as possible (and varying the
power/speed
>by the amount of fuel pumped in). There is one problem with this - It is
>very hard to get a reliable combustion from mixtures leaner than 18:1.
There
>is a solution to this problem (from what my Thermodynamics textbook
says).
>This is by charging the cylinder with a non-uniform mixture. ie: around
>14.5:1 around the spark plug, and virtually nothiing elsewhere (where
>required). This, it has called "stratified charging." Apparently,
engines
>have been successfully developed and run in the laboratory, but not in
>production cars (or at least, we've not seen them...).

The origional Honda Civic CVCC (in the '70s) used a stratified charge
engine It used a two barrel carburater that was set lean in one barrel
and rich in the other.  The rich mixture was introduced near the spark
plug.

I saw the tech articles in Popular Mechanics (or something like that),
and I poked at a junked one when I was in my early teens, but I never
drove one or rode in one.

 The book was first
>published in 1957, with the third edition (the edition that I have)
>published in 1980. I think it is fair to say that our EFI technology has
>advanced quite a long way since 1980. So... Why can't we build direct
>injection petrol engines that vary the mixture instead of the amount of
air
>going in? Since we now have sequential fuel injection, knock sensors
(even
>the Trionic one that we seem to hear so much about on this list - go for
it
>gentlemen...), etc... Why can't we make a direct injection petrol engine
>that uses a combined spark plug/fuel injector, so that we can use
stratified
>charging to our advantage? I reallise that there are problems associated
>with NOx gases produced in excess when lean mixtures are used, but isn't
>that what the catalytic converter is for? Also, wouldn't it be worth
just a
>little bit more NOx in the air (yes, I know NO2 is a poison), for the
sake
>of using far less fuel, and having less benzine rings (which can cause
>cancer) floating around in the air??? Or is there something I've 
>missed?
>
>Danny Barrett.

I had often thought of doing something like that.  A diesel uses direct
injection, of course.

How about this?  (I was thinking of patenting it but what the heck...)

Instead of a spark, heat the fuel without air to a temperature suitable
for combustion.  This, of course, will raise the pressure of the fuel. 
At the appropriate time, upen a valve and allow the hot fuel to squirt
into the hot compressed air in the cylinder.  You can use just about
anything you want (as long as it's flammable and liquid or gas) as a
fuel.  You won't need a throttle plate, so there won't be any pumping
losses.

The trick is to make this "hot injecter" (I would line it with ceramic on
the inside) and put it into the sparkplug hole.  To start with, you could
use the regular distributer to control the timing.  Once you get it
running farily well, try varying the timing to see what you get.

Ray Drouillard

_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]