> Alistair,

Glad you posted this. I was about to start into this when I saw your
post. You covered it about as succinctly as you can get, I think.

Regards,

John
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, AL
> Http://www.moldhaus.com
> Now that's a useful post Dave. FYI, water injection is a known and
> useful technique. it even can be applied to vanagons.
>
>
> "Water injection has been used in both reciprocating and turbine
> aircraft engines. When used in a turbine engine, the effects are
> similar, except that preventing detonation is not the primary goal.
> Water is normally injected either at the compressor inlet or in the
> diffuser just before the combustion chambers. Adding water increases
> the mass being accelerated out of the engine, increasing thrust, but
> it also serves to cool the turbines. Since temperature is normally the
> limiting factor in turbine engine performance at low altitudes, the
> cooling effect allows the engines to be run at a higher RPM with more
> fuel injected and more thrust created without overheating.[2] The
> drawback of the system is that injecting water quenches the flame in
> the combustion chambers somewhat, as there is no way to cool the
> engine parts without cooling the flame accidentally. This leads to
> unburned fuel out the exhaust and a characteristic trail of black smoke.
> Piston engined petrol military aircraft utilized water injection
> technology prior to World War II in order to increase takeoff power.
> This was used so that heavily-laden fighters could take off from
> shorter runways, climb faster, and quickly reach high altitudes to
> intercept enemy bomber formations. Some fighter aircraft also used
> water injection to allow higher boost in short bursts during dogfights.
> As a general rule, the fuel mixture is set at fuel rich on an aircraft
> engine when running it at a high power settings (such as during
> takeoff). The extra fuel does not burn; its only purpose is to
> evaporate to absorb heat. This uses up more fuel, and it also
> decreases the efficiency of the combustion process. By using water
> injection, the cooling effect of the water allows the fuel mixture to
> be run leaner at its best-power setting. Many military aircraft
> engines of the 1940s utilized a pressure carburetor, a type of fuel
> metering system similar to a throttle body injection system. In a
> water-injected engine, the pressure carburetor features a mechanical
> derichment valve which makes the system nearly automatic. When the
> pilot turns on the water injection pump, water pressure moves the
> derichment valve to restrict fuel flow to lean the mixture while at
> the same time mixing the water/methanol fluid in to the system. When
> the system runs out of fluid the derichment valve shuts and cuts off
> the water injection system, while enriching the fuel mixture to
> provide a cooling quench to prevent sudden detonation.
> Due to the cooling effect of the water, aircraft engines can run at
> much higher manifold pressures without detonating, creating more
> power. This is the primary advantage of a water injection system when
> used on an aircraft engine.
> The extra weight and complexity added by a water injection system was
> considered worthwhile for military purposes, while it is usually not
> considered worthwhile for civil use. The one exception is racing
> aircraft, which are focused on making a tremendous amount of power for
> a short time; in this case the disadvantages of a water injection
> system are less important.
> The use of water injection in turbine engines has been limited, again,
> mostly to military aircraft. Many pictures are available of Boeing
> B-52 takeoffs which clearly show the black smoke emitted by turbine
> engines running with water injection. For early B-52s, water injection
> was seen as a vital part of take-off procedures. For later versions of
> the B-52 as well as later turbine-powered bombers, the problem of
> taking off heavily loaded from short runways was solved by the
> availability of more powerful engines that had not been available
> previously.
>
> Use in automobiles
> A limited number of road vehicles with large-displacement engines from
> manufacturers such as Chrysler have included water injection. Saab
> offered water injection for the Saab 99 Turbo. With the introduction
> of the intercooler the interest in water injection disappeared, but
> today, water injection is also of interest because it can potentially
> decrease nitrogen oxide (NOx) emissions in exhaust. The most common
> use of water injection today is in vehicles with aftermarket forced
> induction systems, such as turbochargers or superchargers. Such
> engines are commonly tuned with a narrower margin of safety from
> detonation and hence benefit greatly from the cooling effects of
> vaporized water."
>
>
> alistair
>
>
> On 30-Jan-11, at 11:02 AM, Dave Mcneely wrote:
>
>> water injection you say?  Water injection?  Like in the sixties when
>> all the scam shops were promoting running around with a jug of water
>> draining into the carburetor?   Lots of those guys ended up making
>> license plates.  mcneely
>> ---- VWBrain@aol.com wrote:
>>>
>>> In a message dated 1/30/2011 10:28:07 A.M. Eastern Standard Time,
>>> mcneely4@COX.NET writes:
>>>
>>> You say  that what you have set up is electrolysis.  I would agree
>>> that
>>> getting  enough fuel out of electrolysis aboard a vehicle is
>>> literally a
>>> "fool's  errand."  One would (1) consume more energy than the fuel
>>> would deliver,
>>> and (2) the batteries required would fill up the vehicle.  So I am
>>> quite
>>> confused as to (1) what relationship the device you have set up is
>>> to what
>>> the  original poster is talking about, and (2) whether what the
>>> original
>>> poster is  talking about has much to do with reality, given that
>>> industry has
>>> spent ages  and tons of money working to come up with workable fuel
>>> cells for
>>> application,  while this guy says he is doing it in his garage and
>>> plans to
>>> install it on  his Vanagon.  Interesting ...............  .
>>>
>>> mcneely
>>>
>>>
>>>
>>>
>>> hey guys there was a guy that had this setup in a bay window that
>>> came to
>>> high country campout every year. Hads it in there for years ,
>>> seemed to work
>>> but  only as an additive to the system, not for running oN
>>> competely. said
>>> it did  increases if fuel mileage.   seems like water injection would
>>> probably  work just about the same. bunch of guys are running the
>>> water injection
>>> on their  aircooled vannie and showing a decrease in the head
>>> temps.  later
>>> mark d
>>
>> --
>> David McNeely
>
>