A crazy thought

[john stoffel]

I don't know why but this popped into my head the other day. Take a 195, cnc cut a spacer plate to lower the compression ratio down to 8.5-1. Take out the fuel pump and injector and in it's place a set of points like a Kohler. Machine an adapter to sink a spark plug down into the head and install an Impco LPG carb. Wonder how smooth and quiet it would be.

Okay, I'm breathing through a rag soaked in Diesel, I'll be okay now.

To many service calls working on Nat gas and LP Generators will do that to ya.

[mobile_bob]

John:

i have been meaning to ask you for some time now,

in your travels do you have any of the cat gensets running in dual fuel mode?

such as pilot diesel and natural gas?

if so, i would really love to see one in operation

btw, you might not have to reduce the comp ratio of the 195 if you are burning natural gas or propane would you?

bob g

[Henry W]

Start with a DI S195 ? The compression is 17:1 It seems like it might be less work.

Henry

[veggie]

The company I work for builds electric and engine powered gas compressors for the oil/gas industry.
Many times we are asked to provide systems fueled by NG.
The engine of choice for our system is an in-line 6 cylinder 99BHP diesel Cummins converted to NG with spark plugs and an NG carb.
They usually run 24/7 and seem to last a long time.
I suspect the 195 Changfa would be a good candidate for conversion.

Veggie

[john stoffel]

You know I have never seen any commercial duel fuel (Diesel/LPG) units. The only duel fuel that I know of are Nat Gas/LPG. All of the units we have are Ford, Chevy and Mitsubishi. The Fords are the V-10,V-6, 460cu and the inline 4cyl. The Chevy's are the 454, 350 and as yet to be seen LS1. The Mitsubishi's are just junk. The specs on all of these have normal compression ratios of an automotive/truck engine. I think the 195's compression ratio would be way to high. Cat makes a 3406, 3408, 3412, 3508, 3512 and 3516 in Nat Gas form. The compression ratios on those are down to around 8.5-1. As crazy as this idea is I would like to see someone convert a 195 to Nat gas or LPG. I think it would be very quiet and smooth running. Of course the HP would go from 12 down to 5-6hp. I'm not sure what effect a 17:1 compression ratio would have on this engine. I'll have to add this project to the unending list of crazy things I want to do.

John 

[john stoffel]

What Compression ratio are those Cummins running? There is a company out at Cedar Hills Landfill (King County DNR) that are getting ready to run 32 converted 6 cyl Detroit's on landfill gas that will pump the refined gas into the Pipeline. 

[Henry W]

John,

On the DI S195 there might meat on the piston to machine off on the dish to lower the compression.

If not I bet you can get one custom made from a piston manufacture.

Henry

[mobile_bob]

John and others interested:

check out this link

http://www.energysolutionscenter.org/DistGen/AppGuide/Chapters/Chap4/4-1_Recip_Engines.htm

down the page aways, is some discussion on "pilot" fueled dual fuel engines
the idi changfa looks to be a good candidate for running on natgas or propane in dual fuel
without lowering compression ratios.

interesting bits of info laced throughout this article

bob g

[veggie]

Bob,

Interesting article.
Item 4.1.7 confirms some of our earlier CHP discussions on estimates for heat capture.

Of the total energy input...

Water jacket 30%
Exhaust 35% (Depending on load and exhaust temp)
Rotation force (cranksahft power) 25%
Mechanical losses 5%
Engine block/oil system ambient heat losses 5%

Veggie

[mobile_bob]

the 195 changfa IDI engine is about 32% mechanical output
i would agree to about 5% radiant heat from the block

leaving about 30% output to cooling and 35% output to exhaust

and the balance to other heat losses from various sources

now the DI 195 engine ought to be closer to 34-35% mechanical
and iirc the 1115 DI has demonstrated itself to being a bit better than 35% mechanical

the DI changfa type engines are pretty hard to beat in efficiency in my opinion

btw, an after thought, maybe the unaccounted for losses are energy used to make noise!



bob g