[Diy_efi] LPG injection

[Greg Hermann]

At 7:09 AM 11/28/02, Don Sauman wrote:
>Greg
>
>In this part of the discussion you are talking about Methanol. Does that
>information also apply to ethanol?
>
>Thanks
>Don

It applies, the numbers are different. Ethanol has a high latent heat of
vaporization, don't recall the exact number. However, the stoich mixture
for ethanol requires a much lower proportion by weight of fuel to
air----moroe like 8 or 9 to 1 for ethanol vs. 4 or 5 to 1 for methanol---so
the effects described are not quite as striking for ethanol.

Greg
>
>Greg Hermann wrote:
>
>> At 1:33 AM 11/25/02, Altaffer, Eric EM2 wrote:
>> >>In some ways. It's for SURE why methanol fueled engines tend to foul the
>> >>plugs before they are warmed up!!  It also is REALLY bad for the efficiency
>> >>and hurts the power output when some of the heat of combustion goes into
>> >>evaporating the rest of the fuel !
>> >>You're getting right AT the reason why some of the mfgr's have played with
>> >>that 80/20 ethanol/gasoline mix. At stoich, the latent heat of vaporization
>> >>of that mix is just about PERFECT for having the last of the fuel get
>> >>evaporated JUST as the spark plug ignites it.
>> >>It seems like methanol would be very good at
>> >>surpressing det if this were the case.
>> >>This very much IS the case, and methanol IS excellent at avoiding
>> >detonation.
>> >
>> >There is a bog problem with adding methanol to gasoline.  The o2 sensors
>> >that are on the cars are trying to maintain a stioch mixture for gasoline.
>>
>> Nope. The O2 sensor is EXACTLY that. It senses stoich mixture, regardless
>> of what fuel or fuel mixture brew you are running.
>>
>> >When you add the meth, the car is a bit lean at 14.7.  This is BAD for
>> >detonation suppression.  I live in California where they have introduced 10%
>> >meth into the gasoline and I could not get the darn thing to stop detonating
>> >even at low boost.  Luckily they do not add meth to the 100 octane.  That is
>> >all I run.
>> >
>> >>Not to mention that injecting SOME of the methanol pre-turbo (under boost
>> >>conditions only) would put some internal coolant into the
>> >>compressor--reducing the work needed to do the compression, thus ultimately
>> >>reducing backpressure on the motor from the turbine, and possibly
>> >>eliminating the need for an IC.
>> >>Greg
>> >
>> >Can you explain that one a little more in-depth.  I would never inject a
>> >liquid into the turbo.  Nitrous no problem, but a liquid, never.  I would be
>> >worried about the blades destructing not only from thermal shock, but the
>> >mechanical shock.  Also the alcohol is taking place of air in the
>> >compression cycle.  Since liquid is nearly incompressible, I would think it
>> >takes away from compressing the air.  I would however inject the alky after
>> >the intercooler, or the turbo for those not running an intercooler.  Just my
>> >thoughts.  ERIC.
>>
>> A SMALL amount of atomzed liqud doen't really have much of a negative
>> effect of the compressor blades.
>> All I am talking about is enough methanol so that its latent heat is
>> sufficient to transform the compression process from (near) adiabatic to
>> (near) isothermal.
>>
>> Greg
>> >
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