Date: Sun, 30 Jan 2011 11:23:34 -0800
Reply-To: Alistair Bell <albell@SHAW.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Alistair Bell <albell@SHAW.CA>
Subject: Re: Hydrogen help for the Vanagons
In-Reply-To: <20110130140249.ULKVK.709694.imail@eastrmwml35>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
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
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