Blending diesel & gasolene?

[CLC379]

http://www.truckinginfo.com/clean-green/news-detail.asp?news_id=69628&news_category_id=62

i hope this works as claimed?

there have been similar claims when feeding natural gas or propane into the intake on a diesel but the only efficiency gain seems to be if you dont include the cost of the NG or LP

[mobile_bob]

it appears like a technology that could be adapted far easier to our application than that of an automotive
application, automotive is variable speed and load, while we are at a fixed speed and we can operated under a fixed
load without much trouble.

its pretty cool that the delivery system for the gasoline can be via existing gas engine low pressure injection systems
which i take it to be port injection.

running in dual fuel mode enbles the use of an off the shelf catalytic converter and maybe a compliant engine?

very interesting indeed, and certainly something that warrants investigation and experimentation.

and it is the sort of thing we ought to be able to work with,  getting anywhere between the efficiency we have now
with our engine's and what they report (53%) would be a huge improvement in my opinion.

bob g

[mobile_bob]

ok, so i got curious and decided to run a crude experiment

brought the cogen up to temp and added 2kwatt load, 1800rpm  (changfa s195 idi)

having removed the aircleaner before i started i used a atomizer bottle to gently fog in a bit of RUG while running
under this load and speed.

it doesn't knock until i clearly over fog the thing and then i get some knocking, so there is a limit as to how much gasoline
the engine will tolerate, probably because it is way too much.

a steady light drizzle works just fine.

i would have expected the engine to detonate badly with the admission of any RUG to the intake air stream, but apparently
it does not.

so i suppose it might be possible that one could take the fuel injection system off of a small gas engine, with port injection
with all the sensors and puter, then weld in an injector bung (widely available for bosch style injectors from the hotrod suppliers)
and get a system working in closed loop with O2 sensor and cat converter and have the engine running in dual fuel mode with
gasoline as the alternate fuel.

if i recall "megasquirt" makes a puter to control small single cylinder fuel injection such as for snow mobiles or jet ski's
and is fully programmable and also has lambda support.

it may be possible to get a compliant dual fuel engine with a bit of work, and if the report from the university of wisconsin is
reality based maybe the efficiency of the engine would improve?  of course accounting for the use of both fuels.

that would certainly be a fascinating project for a board member or group to take on in my opinion.

maybe we need to recruit that guy from the U of Wisc to be a member on our forum?



bob g

[rl71459]

Bob

In your 1st reply you mention "off the shelf cat converter". Does this mean that you must use an application specific cat converter to have it perform properly or effectively? or can I just size one to fit my exhaust system pipe size and have proper performance?

Is there a difference between a "Gas" or a "Diesel" cat converter? Or will either work the same?

Hope this does'nt derail the thread... Not trying to hijack it.

Rob

[mobile_bob]

no problem Rob:

the biggest issue i have found with cats for diesels is finding one small enough for a 12hp diesel engine, and

the next big problem is gettin enough load on the engine to get high enough exhaust temp to light the cat, and

the next problem is particulate matter, soot and devising a method of of particulate matter reduction or filtration.

i found that magnaflow makes a cat small enough for my application, and i can run the engine under sufficient load to
get the cat lit off (presumably), leaving me with the particulate matter/soot issue which i am working on a regenerative
filter to handle.

that was one of the things i found interesting about the diesel/gasoline topic, if one could offset 85% of the diesel with
gasoline, the net effect would be at least an 85% reduction in particulate matter, which dramatically reduces the particulate
filter requirement.

btw, diesel cats are generally built to withstand more vibration than those made for gasoline engines, often using a metallic
substrate instead of a ceramic one. other than that the function is basically the same as far as i know.

bob g

[rl71459]

Thank You Bob

[mobile_bob]

Jens:

i have no doubt that audibly there would be little to no difference between fogging water and gasoline, but

you cannot burn water, and water will reduce the amount of power produced (generally) for the same amount of diesel consumed,

on the other hand, gasoline as we know does burn, and in doing so offsets the amount of diesel consumed, for the same amount of
power produced.

now having said all that, i have no idea if the engine runs more thermally efficient? or not?

only way i know to find out is to setup a metering device to fog gasoline into the intake in dual fuel mode

first run a BSFC test at a specific load, specific rpm, etc, on straight diesel, and then
rerun the test changing only one factor, that factor being the admission of gasoline fogging into the intake

then measure the amount of both diesel and gasoline used in the second test, and compare the results with that of the
first test to see if there is a reduction in BSFC after factoring in the difference in btu content of the fuel as well.

if what the report states is true i would expect to see a reduction in the BSFC as measured in a corrected gr/kw/hr produced

how much i don't know, but it might be significant?

i just can't imagine how else they are admitting gasoline into their test diesel engine, reportedly they are using a low pressure
gasoline automotive injection system which means it has to be port injection and not a mixed fuel system or high pressure inject
into the cylinder system.

i have to give this more thought, there might be a way to admit the gasoline via a drip method under load so that i can get some data
that might shed some light as to the validity of the  process.

personally i am not about to spend a pile of cash buying parts and a puter to add EFI to the changfa as an experiment until i can witness first
hand that there is something to the story.

if the story is true,, we ought to be able to replicate the process enough so that we could see a relative improvement in efficiency, it shouldn't be any worse?

i should'a be born a rich man's son!

work keeps gettin in the way of experimentation  

bob g

[Chris]

Just a thought, and I am sure, others more educated with internal combuston engines can shoot it down, but would not the fogging with water turn the water into steam and would not the expansion of water to steam increase power? Or would this just cool the combustion down and negate whatever apparent power was gained from the steam?

Any thoughts?

Chris

[mobile_bob]

from what i remember, and my memory is about as long as something else i have...

the expansion from the steam providing power is offset by a reduction of temperature of the fuel air charge.

and iirc there is a special cycle that uses the expansion of water to steam in a power cycle, but i don't recall
how it is done,  i am thinking it was an added cycle requiring a different cam gear and profile.

more to have to go back and research...



bob g

[CLC379]

Thanks Bob

for putting this to a test, looking forward to more opinions and results

[Lloyd]

SmartPlugs...iirc...they used(water injection) in conjunction with a diesel injection...to cause a more even flame propagation, which in-turn caused a more complete combustion, which in turn actually increased power out, and reduced emissions..and steam-cleaned the combustion chamber at each firing.

Now...maybe rug could be used in place of the water with a smartplug??

Lloyd