Re: GAS-L: Internal Combustion with Producer Gas

[Peter Singfield <snkm@btl.net>]

Tom T;

Excellent point!! So the only way that could work would be by high pressure
injection of producer gas -- hardly feasible.

And really great to know about those new diesels already set up for gas.

That might mean that simply buying their injector conversion and electronic
ignition set up -- without changing compression -- could work on producer
gas??

My -- now we certainly are learning so much!

Oops -- had a nagging memory that early electric power plants were using
gas powering two stroke diesel engines -- so went and checked it out --

Scanned in:

Gas Diesels-

These engines induct an appropriate amount of gas with the air charge and
inject a small amount of diesel fuel about 5% of the total fuel, at the
proper time to act as a pilot charge to produce ignition. The amount of
fuel oil injected is the minimum that can be dispersed throughout the lean
gas-air mixture in the combustion chamber to ensure ignition at many
scattered points, and is constant for all loads. The amount of gas inducted
is varied by a governor to meet the load requirement.

A second type of gas-burning diesel is called dual-fuel diesel; it differs
from the gas diesel in that provision is made to supply more fuel oil and
induct less gas when the supply of gas is inadequate.

A governor automatically increases the fuel oil injected from minimum 5% to
as much as 100% of the total fuel as the available gas decreases.

Fig.7 is a sectional view of a four-stroke-cycle, dual-fuel diesel, showing
the timed valve for introducing gas into the air stream outside the inlet
valve and the injection system for spraying oil into the combustion chamber. 

Two-stroke-cycle gas diesels are equipped with timed gas valves in the
cylinder heads to admit the gas immediately after scavenging has been
completed, preventing its escape with the exhaust gases.

All large stationary-power-plant diesels are built to burn gas because the
cost per unit of energy supplied is much less for natural by-product gases
than for even the cheapest fuel oils.

BIBLIOGRAPHY. - American Society of Mechanical Engineers, The Fifty Years
of the Diesel Engine in America (1949)

***********************************************

Are you sure that the charge would be ignited when the blower scavengers
the cylinder. Have you tried it?? 

Hey!! -- seems they were doing OK pre 1949 -- they show a nice picture of a
12 cyl., 8650 h.p. unit for the above purposes.

Why are we always re-inventing the wheel on this list?? Now I could live
with five percent diesel. And also -- it clarifies my comment about
flaming, rather than spark igniting -- the charge -- for 100% operation of
producer gas in a standard diesel engine without lowering compression!

I hope that point is taken properly this time around?? I do believe Prof.
Parikh/Shashikantha did once mention that "knocking" becomes a problem past
the 12:1 ratio if operating direct spark ignition using producer gas??

That is detonation rather than ignition. "Flaming" would probably make sure
it was ignited -- not detonated -- allowing greater over all efficiencies.
It would flame rather than detonate in the chamber machined into the
injection hole plus adapter because of the much smaller volume. The flame
so created would more equally ignite the main charge mixture.

Comments??

Peter/Belize

At 04:44 PM 5/3/00 EDT, you wrote:
>Peter in Belize,
>    The point I was trying to make was that the combusting gas when exposed 
>to the incoming air fuel mixture would detonate in the inlet manifold, and
if 
>this did not result in explosion, it would deplete the fuel from entering in 
>the cylinder denying the engine power for the next stroke.  Two strokes have 
>never been used for naturag gas firing have they in spite of the fact that 
>most are in an acceptable compression ratio to be used on natural gas.
>    Cummins and Cat both use the diesel blocks for natural gas engines, 
>changing out the compression, injectors for spark plugs and electronic 
>ignition for injector pump where applicable.
>    I don't think converting GMC 2 stroke engines will work.  
>
>Tom Taylor
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