gasifier fed dual fuel diesel?

[mobile_bob]

Jim

thanks for your input on the other thread as it relates to issues in dual fueling a diesel engine with woodgas,
however it raises some niggling thoughts in the back of my head.

correct me if i am wrong with any of my statements, assumptions, or thinking

a diesel engine while able to run with intake restriction (needed to draw woodgas from a gasifier)  really is not made to do so
the engine is made to run with excess air (oxygen)  however the gasifier need to have a draw on it to operate.

in my reading it looks like most gasifiers have a blower to initiate the process, which is turned off after things are going and the gasifier
then relies on the engine to provide the continued draft to keep things cooking?

the problem i see with this method of operation, while successful with spark engines is apparently, when used with a single cylinder engine is the pulsating
nature of the intake (engine drawing a gulp of air every other cycle) and sizing issues with getting the gasifier sized properly for the displacement and fuel needs of the engine?  this gulping of air surely does not keep the gasifier operating at its best, probably not as well as if the blower were continued in use?

so what do you do?  i guess you can't keep the blower going if you are going right to the engine?

how about if you used a buffer, such as a large gasbag arrangement so that the blower could continue to be used, this would do two things
keep the gasifier operating in a stable manner and  remove the need for the engine to have to have a throttle/restriction in order to draw in gas.

then you could get the gasifier running properly, producing clean good quality gas continuously, and be able to capture it in the buffer/bag, and from their transport it to the engine intake airstream with any sort of mixer.  this would eliminate the engine from having to draw in the gas to keep the gasifier operating correctly.

so how would one keep a good balance and not overfill the gas bag? i suppose one could use a reostat on the blower so that a blower speed could be found that provided a good balance of produced gas and the demand for that gas.

what i am getting at is this

i don't like the idea of pinning the injector rack, this really hinders the proper diesel operation of the engine in both modes, standard and dual fuel.
and is possibly a good way to have a runaway and a horrible catastrophic failure.  if the injection system is left unmolested/unaltered then the governor will operate as needed in both modes, there really is no need for a throttle plate connection to the governor via linkage, because there would be no throttle plate for the thing to operate,, you just get the fuel to the mixer/intake airstream and let the governor take control of maintaining speed by varying the diesel injected.

the only thing you would be concerned with is limiting the maximum amount of woodgas delivered to the engine, which could be done via an orifice arrangement and some sort of weighting of the gasbag

when you pin the governor it becomes both unsafe in my opinion but also dramatically narrows the window of operation where everything has to be spot on perfect for the system to operate effectively, and it would be one finicky sonofagun to get setup to run right, and it would require constant tweaking while running and likely not start and run a day later which would require more tweaking of nearly every adjustable part of the system, both engine related and gasifier.

i guess what this comes down to is this, i have never heard of pinning the rack to run in dual fuel mode, every reference i have seen relating to running a diesel in dual fuel mode using a gaseous fuel never pins the fuel rack.  i can't see what wood gas would be any different in this aspect and i suspect that doing so was
an effort to work around problems with sizing and the intake pulse upsetting the gasifier making it less than stable in operation.

i am interested in your thoughts on this

as for setting up to run on woodgas alone, and getting away from burning any diesel,
while this is an interesting concept or goal perhaps it comes with some serious compromises you don't have to make?
to get away with not diesel you must alter the engine in ways that make it unusable as a diesel engine without taking time to
reverse all the modifications, and also end up with lower power than would be available to you in dual fuel mode.

we don't have to burn diesel as the pilot fuel, we can burn kerosene, bio diesel, veggie oils (waste and new) waste motor oils, hyd oils, trans oils
to name a few. reducing the need for liquid fuel by nearly 90% is a long way toward not burning them altogether.

as the old saying goes, and i am paraphrasing

you get 90% of the result with 10% of the effort (money and time) the last 10% will cost you 90% of your effort (time and money)

perhaps getting away from burning all liquid fuels is just too much trouble?

in the end it is much more desirable to maintain the oem governor and injection system, with pilot injection if for no other reason than maintaining the
rpm range needed to produce stable 50 or 60 hz power with a generator. i am not convinced that the gasifier fueled spark converted engine's can maintain
a stable rpm for stable 50/60hz operation without someone baby sitting the system making frequent adjustments while in operation, with the varied nature of shifting loads and the varied nature of a gasifier in the course of its operation.

thoughts?