Should we consider LP and Nat. Gas CHP systems instead of diesel?

[BioHazard]

Couldn't sleep last night, so I was thinking about the conversion of a diesel engine to NG or LP.  What does it take?  You need spark, fuel, and compression.  Compression is fine, whatever it is.  LP will not autodetonate even at diesel compression ratios, so that makes it easy.  Is NG the same?  Spark is not terribly difficult if you re-use the injector hole.  The listeroids could have the sparkplug in the compression changeover plug.  Use a small engine coil or one of the after-market electronic ignition units.  That only leaves controlling the fuel.  You can get an IMPCO propane carb/throttle body for under $200.  Make a linkage to the governor, or get/make one of the electronic ones.

I'm glad I'm not the only one who stays up at night thinking about this stuff!  Obviously it's doable, Arrow has done it with the Petter clone they sell. My concern would be the cam and how efficient it would run on gas. Might run like crap without a new one. Also might be kind of hard to set the ignition timing. I don't know what the max CR is for natural gas, but I know all the spark converted diesels I have seen have lower compression than a diesel. With the availablity of those Kawasaki engines I don't know that it would be worth the cost to convert a listeroid.

I have no clue if the engine will run at all well, but I don't see why not.  The thing I'm trying to decide is if it makes more sense to get a small honda civic engine, add a large flywheel, and run it slow at 900rpm.

What causes an engine to wear out?  The number of engine strokes?  Un-oiled starting?  Run the engine slow and adding a pre-run oil pump should make it last longer.  The question is:  just how long?  I've heard of a Honda engine running for 13k hours when it wasn't started all that often.  How long would a cheap used Honda Civic engine last?  I see them on ebay or Craigslist for under $500.

This is the kind of thing I have been thinking about for a while now, but I have started to notice all the commercial cogen systems use a smaller engine. It kind of bothers me that a Kawasaki 2 cylinder is $1000 and a 4 cylinder is about $500, but how much is it going to cost to convert the engine? If you put 300,000 miles on your Civic running at 25mph, that would be 12,000 hours. I would think the engine would last quite a bit longer in stationary use with good maintainence.

Personally I think I'm going to have to bite the bullet and go with a Kawasaki or Kohler water cooled V twin. I wonder if the Kohler parts are easier to find?

[BioHazard]

One important thing, I would have a couple spare starters. They are not heavy duty.

Personally, I'd like to come up with a backup pull/crank starter system, if being used for a generator. I figure if I can pull start my 6 cylinder boat engine I can probably pull start a V twin.

[mobile_bob]

i am not sure i would invest the time to convert a listeroid to nat/gas, however it probably would run quite well for a very long time
due to lower stresses, or so it would seem.

the kawasaki looks interesting, as does the kohler
however i am not crazy about aluminum blocks and the other corners that are cut to save weight
which is necessary for their intended use.

if however that is all that is available to work with, i guess you dance with the girl available when the song starts?

looking back at the changfa something came to mind the other night, (yes i too stay up nights thinking about this crap)

the s195 comes in both di and idi configurations
the di comes with a dished piston, and sans prechamber
the idi comes with a flat top piston and a prechamber... so

we spec an engine kit to come with a di piston, and an idi cylinder head
the coupling of the two should lower the compression from around 20:1 down to something like 12:1 or so.

the selling point to the epa is such an engine kit could not be readily fitted with an injector and injection pump
and be made to start with anything less than a nose full of ether, if at all. the compression ratio would be too low.

perhaps if this solution was presented to the epa, with the explanation that the kit is for research, to be fitted for nat/gas or propane
and cannot be made to run as a diesel engine by simply bolting on the missing parts?

i think a good case could be made

changfa will not even talk to anyone about any engines without a letter from the EPA, so if this was packaged and presented properly
it might be the EPA would allow for the import of such a "part" and provide us with a letter ok'ing the import.

i am unaware of any  of the smaller engine's such as the 175 coming with either di or idi configurations, i think the 195 is the smallest that
comes either way.

having that option simplifies the project because a special piston would be unneeded.

bob g

[BioHazard]

the kawasaki looks interesting, as does the kohler
however i am not crazy about aluminum blocks and the other corners that are cut to save weight
which is necessary for their intended use.

I agree, the aluminum block makes me a little leery, but then again these days even cars come with aluminum blocks w/iron sleeves. I think the Honda micro CHP system uses an aluminum block, but I'm not sure.

Even at $1000 I still see the engine as semi-disposeable. Stuff like generator heads, inverters, etc, should outlast several engines. My first job would be to increase the size of the oil sump/filter.

[BioHazard]

Yep, the Honda CHP system uses an aluminum block engine.
http://www.builditsolar.com/Experimental/CoGeneration/HondaCHPbbezilla.pdf
Interesting that I see it's got a 163cc engine. What are the odds it's a GXV160 with a water jacket?
http://engines.honda.com/models/model-detail/gxv160

[mobile_bob]

makes sense that they would simply make a water jacket block for the gx160 aircooled engine components

the gx160 is one tough little engine in aircooled
i can't imagine it would be any less so as a watercooled unit.

bob g

[Henry W]

Yes they are tough engines. I have two comercial mowers with the GXV160 engines and they took a lot of abuse. They still run great.

Henry

[Henry W]

I just did some research on the Briggs Vangaurd V-Twin I have. It is made in Japan by Daihatsu, a member of the Toyota Group. The engines crank is supported by a ball bearing on the load side. and replaceable bushing on the flywheel side. Side loading would not be a problem with this engine, the Kawasaki and Kohler engines crank has bushings machined onto the crankcase on both ends. to bad the Vangaurd V-twin engines are air cooled only. From looking at all the parts manuals I feel the briggs Vangaurd engine would have the edge on air cooled engines.

Henry

[Henry W]

I was thinking. Now how can heat be harnessed by the Vangaurd  Propane V-twin. Heat extracted from exhaust and oil is easy. Can the cooling air  be collected effectivly by a heat exchanger? Or how about this idea. I am total electric, and I run heat pump in the winter. How about pumping all the heated cooling air from the engine in the outside condenser unit on cold months. Won't this make the heat pump much more effecent? Won't this work on the Honda GX160 as well?

Henry

[veggie]

In Canada (in the oilfields) the Cummins 6 cylinder NG/diesels are all over the place.
As Bob mentioned, the injector port is modified to accept a spark plug, and an ignition kit is added.
These things burn very clean, have extended oil change intervals, and seem to run for ever.
There is one site I am aware of where the engine has been running pretty much 24/7 for 5 years (apart from regular maintenance shutdowns). IIRC, the compression ratio is altered considerably for NG use.
With the lower compression ratio and the absence of the diesel knock, the rods and bottom end have a greatly reduced operating load.

veggie

[Henry W]

Finding a liquid cooled single cylinder engine in the US pretty much a dead end.

Liquid cooled engines currently available in the US are:
Kawasaki V-Twins and Kohler V-Twins.

I just found this. Are Briggs liquid cooled V-twin still available? Possibly.

http://www.briggsandstratton.com/support/frequently-asked-questions/B%20and%20S%20Liquid%20Cooled%20Specifications/~/media/C8984755FCB54B3EBDD5C4915223F27E.ashx

http://www4.briggsandstratton.com/miscpdfs/RNT/vanguard_2lc.pdf

They look like they are very good engines.

Henry

[deeiche]

Anyone consider used JDM Kei engines?

If you don't know, Japan has a class of cars called Kei.  Their displacement is set by law, right now at 660cc.  They are water cooled 4-stroke engines, most taken off streets at 10 years because of strict safety and emissions tests that escalate in price as vehicles get older.

The JDM pipeline into the US is pretty well established.

[mobile_bob]

got a link to these engine sales?

bob g

[BioHazard]

I knew I'd seen a water cooled Vanguard somewhere! I think they've already discontinued it though, it's not on their "commercial power" website.

Here's one on ebay, a tad spendy:
http://www.ebay.com/itm/35hp-Briggs-Stratton-Engine-ES-Vanguard-Liquid-Cooled-1-1-4-x4-1-2-613177-0115-/360461161664?pt=LH_DefaultDomain_0&hash=item53ed28d4c0

[Henry W]

They are not cheap. I think you are right about them being discontinued. I wonder why.