Fw: [Diy_efi] compression ratio

Marteney, Steve Steve_Marteney at DRSOptronics.com
Thu May 9 17:52:12 GMT 2002


What about combustion inefficiency and bad mixing?  I'm a complete novice on
this subject, (so bear with me) but I'll give an example thought process.
14.7:1 is actually the INTAKE air-to-fuel ratio and theoretically the exact
amount of air and gas needed to completely use each.  If you throw 14.7:1 in
and issue no spark, obviously you will make no power (extreme example).
Likewise, you throw in exact 14.7:1 but the combustion chamber has excessive
swirl and spreads the gas out.  So, to guarantee that you absolutely burn
100% of the air taken in, you don't throw the EXACT amount of gas in to make
14.7:1, you throw in a little more fuel (just like padding a budget :-)
because of bad mixing.  OR... you throw in more fuel because your air
metering isn't that precise and you again want to make sure you burned all
the air.  That's always been my thought process on that matter, right or
wrong.

I never thought of the cooling aspect.  Thanks to whomever explained that.
I learned something.
-Steve
-----Original Message-----
From: bearbvd at mindspring.com [mailto:bearbvd at mindspring.com]
Sent: Thursday, May 09, 2002 2:18 PM
To: Diy_efi at diy-efi.org
Subject: Re: Fw: [Diy_efi] compression ratio


At 11:29 PM 5/8/02, Grant Beaty wrote:
>Wow, thats a lot of water. I know this is a bit OT (the thread is anyway),
>but if you spray water evenly into all cylinders, can it take the place of
>fuel? That is, could you theoretically run 14.7:1 at WOT, spraying water
for
>cooling instead of fuel? My setup will be 2D mapped, so I can take out fuel
>and the water injector's duty cycle increases.
>

Excess fuel beyond about 14.2 to 1 af ratio is virtually all simply
internal coolant, and can be replaced by water. The excess fuel between
14.7 (stoich) and 14.2 (or so) will give more power--because the hydrogen
in the fuel burns selectively over the carbon, and gives a higher heat of
combustion when it does so.

(Sir Harry and Obert agree with this.)

Greg



_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi

_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi



More information about the Diy_efi mailing list