Author Topic: JD175 China diesel running at 500 - 1000 RPM  (Read 48383 times)

Thomas

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #75 on: November 18, 2007, 07:52:20 PM »
Hello to every one  just looking at the pic's of the coupling you made it looks very much like the ones found on an Otis Elevator to atach the moter to the hoist unit.  Thay are I thank used on other drives as well.  We found that the rubber inserts woud go away after a while lots of stoping and starting under load thay stoped using them some years ago. Tom T

rcavictim

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #76 on: November 19, 2007, 01:07:03 AM »
Here is a picture of the mostly completed plant from the pulley and exhaust outlet side.  That safety screen earned it`s keep first run today.  I had been playing with a piece of exhaust pipe slipped over the muffler outlet to get the exhaust farther from where I was working and it fell off and the end whacked into the screen harmlessly instead of entangling itself in the rapidly spinning pulley spokes and belts!!!!


-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

rcavictim

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Bad news....necessitates major change in plans
« Reply #77 on: November 19, 2007, 08:35:55 AM »
First thing I did today before running fuel consumption tests was to increase the shim thickness behind the FI pump flange from 0.033 inch to 0.056 inch.  That is almost as much as adding a second factory gasket as a spacer.  How much this delayed my timing in actual degrees I do not know as I was unable to get my dial indicator to ride the pump cam without making a special extension and I had more important use planned for my precious time today.

In running tests today after retarding the injector timing it seemed happy enough and was able to tick over incredibly slow, no load very smoothly.  We are talking like 150-200 RPM slow.  Anyhow, about 40 run minutes into the 1050 RPM loaded testing the diesel knock suddenly started getting really loud and climbing in intensity very rapidly.  I was right there and closed the rack within seconds.  As soon as fuel was shut off the bad noise instantly ceased.  When fuel was re-applied the death knock reappeared.  I shut the engine down leting it coast.  I took note that I had full normal oil pressure at the time of the knocking event.  Just before the engine stopped revolving I closed the compression lever and the knock returned under piston compression only load. Hmmmm.

I removed belts separating the gen heads to aid diagnosis. The engine rotated as smoothly as before making no untoward noises while being rotated by hand, except for a curious cklink sound at one spot on the rotation that I only became aware of as separate from normal engine sounds I had always heard before while rotating slowly by hand.  If this was a lower rod bearing tightness there would be problems felt. Also I would not expect the rod bearing to fail so suddenly. I began to fear the worst, that I had developed a crack in the crankshaft.  :(   Pulling the inspection door all looked fine. Hand wiggling the con rod the lower bearing appears to be absolutely fine.  After many minutes of careful inspection with a powerful flashlight and rocking the flywheel around by hand I noticed that one of the large pins in my DIY coupler has once again broken it`s weld.  This appears to be the site where the metallic death knock was occuring.  I called it quits at this point as I am totally burnt out after working long and odd hours on this thing.

My pause has given me a chance to re-evaluate what I am doing. I am now armed with actual operational test data from which to base my decision on how best to proceed.

The bad news is I am giving up running the JD175A at 1050 RPM. Not enough power and it appears that today I broke another pin weld on my Beta coupler despite retarding the injector timing and am absolutely dumbfounded as to how this is occuring.  Perhaps in small flywheel-rubber-large flywheel I have inadvertently created a resonant system with unequal weights on each end of a spring.  Whatever it is, it is clearly a problem and looks like the peak forces threated to do serious damage to other components, most likely my small flywheel to engine crank interface and the engine itself.  Must modify the design!

More bad news is...  I did a fuel efficiency test on the AC gen head and I get a rate of 0.75 Litres per kWh with a 500 watt output which is near max capable output.  That is terrible fuel efficiency!  My VW plant gets about 0.33 Litres/kWh.  It is also just not enough power for the investment of hardware here, or my needs.  I was expecting twice this.  My generator heads individually have 4X that as continuous ratings.
 
I have devised a plan to install an intermediary shaft and another set of belts for about 2:1 reduction from the engine to the big flywheel shaft.  I will be able to run the engine at ~2000-2200 RPM and get full AC power rating output from my AC head as well as the DC head (individually) and still have the huge flywheel running at 1050 RPM to give the set high surge load capability (especially important on a low powered genset IMO).  That would allow me to run an air conditioner off this.  Without the big flywheel I`d never get the compressor to start. Fortunately my modification can be done with no changes to what is done now except removal of my trouble prone coupler.
 
The success of this idea depends on having enough room where the coupler is now for the factory supplied 2 belt shieve.  I have not measured yet but I know it will be close.  Actually I might grab a gimler timing belt and toothed pulleys from an automobile 4-cylinder  engine cam shaft drive.  They give 2:1 reduction and a small engine timing belt, 1 inch wide may be is about the right length center to center for where this is gonna go. That would really cut down on the loss I`d get from another set of V-belts!!!!  I just thought of this and I like the idea over V-belts even if it means yet a bunch more lathe and shop work.

I need to look at the plant tomorrow and see what room I have to add the reduction jackshaft system and get started on the upgrade.  Once done I will have a plant that much better utilizes the capability of the little JD175A engine, has extra power in reserve to overcome the V-belt drive losses,  will operate at a speed where the engine is most efficient, and provides decent output power fully utilyzing the capability of the heavy duty quality generator heads now installed.

So...the saga continues.....

 
There will now be a short intermission.
« Last Edit: November 19, 2007, 09:35:58 AM by rcavictim »
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

mike90045

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #78 on: November 19, 2007, 04:05:03 PM »
Have you looked into DIY cast in place, polyurethane bushings ?  They may not solve your broken pin problem, but will be much tougher than any rubber bushing.  Or, look for some polyurethane bushings for automotive shocks, that are close to the right size to drop in.

As to the welds breaking, maybe it's the filler wire you use, is too brittle, maybe another type will hold up better, or maybe post weld annealing may help ?   If they can weld 20" armor on a battle tank, there is a weld technique that would hold the pins on (and their matching sockets) if you get the right filler metal. 
 Maybe a larger pin, tapped internally, and bolted to your counterbored plate, and then welded ?  Does the weld break, or the pin metal ?

mobile_bob

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #79 on: November 19, 2007, 09:38:05 PM »
pehaps you can get away without welding
you might try a shouldered wheel stud such as used on hd semi trailers with inboard drums
the come in all sort of sizes and have a nice collar, you slip it thru your drive, torque up the nut
and then the stud sticks out the other side into your rubber bushings

some are quite long so you can cut off the exposed thread end and get to a clean section or
what is about 3/4 " in dia, if i recall
being grade 8, they will take alot of beating without failing

pretty cheap too

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

rcavictim

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An elegant solution to the problem has been implemented
« Reply #80 on: November 19, 2007, 10:48:27 PM »
Thanx for the suggestions but you guys are missing the point.  The engine has insufficient power by a large margin at the low speed.  I mentioned that I was expecting almost twicw what I was seeing. On top of insufficient power the fuel economy was in the toilet. The ONLY solution is to increase the RPM into the region for which this small engine was designed to operate in.

Today I came up with a simple and elegant solution that is so slick it looks like I designed the plant this way in the first place.  I need to build another bearing equipped belt idler tesioner, and put the injection pump timing back where it was and I`m done.  The new plan uses the factory supplied 3.9 inch twin B vee belt pulley bolted up to the engine flywheel in the space between the two flywheels where the troublesome coupler was.  From this pulley two B-belts head upwards to a 5.75 inch dual belt pulley on the rear unused shaft of the DC gen head. The alignment of this path is perfect!  The gen head acts as the intermediary shaft to get the power to the front Vee belts that tie the two heads and large flywheel all belted together.  Operating the JD175A at 2200 RPM will get me 1050 RPM on the big wheel, 1800 on the AC head and 1500 RPM on the DC head.  Perfect!

I expect full nameplate AC power of 2 kW and huge starting reserve current and no lamp flicker thanx to the big flywheel .  Ditto for the DC head.  If the AC head is not needed I can pull the front belt and the DC head is belted directly to the engine for max efficiency by shedding extra belt and windage losses.  I can belt the big flywheel to only the DC head if desired as well, ignoring the AC head entirely.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

ZackaryMac

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #81 on: November 20, 2007, 01:04:03 AM »
And for exrta boost, particularly at start-up, when trying to get that big flywheel to speed, you can give 'er large doses of ether to wake it up...y'know, like nitrous, but not nearly that complicated!!   ;D  :o

Spray a bunch into a cup and splash it into the open intake. No really, it'll be great!!!   ;D 

(In case someone reading this actually thinks it a good idea, IT'S JUST A JOKE! - well, you never know...)


Just trying to keep your sense of humour up, rcavictim.
It didn't work like you thought, but you gained a lot from the experience, for future projects. Now you're the guy that KNOWS, not a guesser (like me, anyway).

I'm envious of your construction capabilities. I usually cobble stuff together that sort of works but looks like it was thrown out 20 years before.  :P
Kubota EL300A-R 4hp 12v Generator
Kubota B6100 HST Compact Tractor
Onan RDJA 8hp
1994 Chev S10 w/Isuzu C223
All are diesel.

rcavictim

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #82 on: November 20, 2007, 05:36:06 AM »

Just trying to keep your sense of humour up, rcavictim.
It didn't work like you thought, but you gained a lot from the experience, for future projects. Now you're the guy that KNOWS, not a guesser (like me, anyway).

I'm envious of your construction capabilities. I usually cobble stuff together that sort of works but looks like it was thrown out 20 years before.  :P

Thanx for the compliments Zack.

As you may recall I had been attempting to coax anyone who might have experience with running China diesels at slow speed out of the woodwork for quite some time with no real luck.  I had to take the DIY approach to discover the pitfalls all by myself.  I`ve spent a lifetime doing just that so it is entirely in character for me to go off and DIY `er DIM.   :D

As for the look.  I am a real fussy perfectionist when it comes to my own work and in a way it is a curse because I cannot just throw even completely experimental, proof of concept prototypes together without finishing them up looking nice as part of the path to determine if the design is a good idea.  That can be really risky.  This project and everything else I build is a best example of this theme.  I am fortunate that very seldom have I ended up with scrap, so I must be doing something right.  Part of the reason I work like this is because I know that once a project has been prototyped and is performing the function I am completely psychologically incapable of building it a second time all pretty. My mind craves that I have to move on to the challenge of the next project.

Don`t worry about my sense of humor getting lost.  I was born with a dominant silly gene.   ;D

I went to Princess Auto today to get the 5.75 inch dual v-belt shieve and while there picked up a digital laser tachometer that I`ve been wanting to get for $40.  With flywheels involved it is essential that I know for sure what the RPM is of these projects.  I plan another higher power generating plant using a Changfa 1115 engine in the near future to become a backup, or prime replacement for my 9 kW DIY 1.5 litre Rabbit diesel powered  plant which powers and heats my shop.  Once off grid, my goal, I consider being prepared in advance with turnkey ready backup plants essential good planning.
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

mobile_bob

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #83 on: November 20, 2007, 07:36:02 AM »
RCA:

check out this ebay link
http://cgi.ebay.com/KUBOTA-DIESEL-ENGINE-6-5-HP-WATER-COOLED-APU-EB300-D_W0QQitemZ260182352009QQihZ016QQcategoryZ11754QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

it is for a 6.5 hp kubota
look at the pics down the page, where the hyd pump and particularly the drive is illustrated

it appears that it uses steel sleeved rubber bushings that bolt directly to the flywheel on the typical 3 bolt pattern

might be useful to ya, in case you decide to revisit that type of drive

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

rcavictim

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #84 on: November 20, 2007, 11:50:30 AM »
RCA:

check out this ebay link <snip>
it is for a 6.5 hp kubota
look at the pics down the page, where the hyd pump and particularly the drive is illustrated

it appears that it uses steel sleeved rubber bushings that bolt directly to the flywheel on the typical 3 bolt pattern

might be useful to ya, in case you decide to revisit that type of drive

bob g

Thanx Bob!  I see what they did.  The Kub hydraulic pump coupler centers the force on the pins (3 bolts that go into flywheel) so that in that area of the coupler there are lower bending (lever) forces on the `pins`.

Well I am off to the shop to make my ball bearing roller belt tensioner and restore the IP timing.  Today ought to be a good day once done, all going well.

I get a chance today also to try out my new digital laser tachometer!   :)
« Last Edit: November 20, 2007, 11:52:57 AM by rcavictim »
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

diesel guy

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #85 on: November 20, 2007, 09:48:23 PM »
rcavictim,

About the poor fuel economy, what I discovered in both gas with a carburetor and diesel engines with mechanical injection, is that the best fuel economy is right at the maximum torque peak. This is when the engine produces the most mechanical output vs. fuel consumption. I think your engine has a torque peak much higher than you were operating it and it was not offering high volumetric efficiency.

About the break down, I think (I could be wrong) your engine crank is very light and even with conservative injection timing, the piston seems to me that it would slow down quickly from the compression just before injection, due to the lack of stored kinetic energy but your heavy weight flywheel didn't. Causing a twist. Then when the fuel was injected, the light crank would accelerate quickly but your heavy flywheel didn't, causing a twist. This twisting back and forth might be the reason to your breakdown. A belt attached and not direct connection would help lower the twisting action by the belt taking up the differential in speed. Just my opinon.

Diesel Guy


rcavictim

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hi-speed modification now installed
« Reply #86 on: November 21, 2007, 12:00:11 PM »
Well my clever modification is a faite-accompli (sp?).  The engine nows spins at 2200RPM to make 60 Hz AC power. I  tested for an hour last night after getting the retrofit manufactured and installed.  The idler is a solid dual B-belt shieve turned from aluminum billet and uses the same two pressed-in sealed ball bearings like the flat back-of-belt idler I made or the front beltway.  This new idler iis also adjustable for optimizing and maintaining belt tension.

I had 1100 watts load on the AC head spinning at 60 Hz speed and 700 watts simultaneously on the DC head (115 volts DC).  No black smoke.  I did not have the wiring set up at the time to add additional load.  Today I`ll run more tests. Woah, what a racket!!!!!  I am going to definitely put an intake silencer on this plant now.

Fuel consumption spinning everything, all these parasitic belt loads, windage and etc.,  was measured at 0.59 litres/kWh over a half hour test after complete warm-up.  Not great.  Speed regulation was not bad.  I suspect that I can dial this in with a little effort.

Engine temp stayed steady at 190 F.  There was a constant flow of nice warm air from the radiator like a 2 kW electric space heater.  In my previous test setup I had warm air that would pulse and cool, pulse and cool.  This is much better now for getting useable co-gen heat for the shop.  I just have a pair of 6 inch muffin fans on the radiator for these tests.

The noise goes way down as the RPM.  It appears I will be able to loaf the plant along at much lower RPM if all I am doing is maintaining charge on my 48 volt battery plant (the prime reason I built this plant).  The big flywheel is really helping out!  Today with additional testing I plan to re-belt so the AC head is off belt.  Just big flywheel and DC head.  That is the config I am really concerned about regarding the long term fuel economy, engine wear rate, noise level, etc.  I suspect I`ll be able to get away with about 1500 engine RPM in this mode.  I`ll report on my test results when known.

Here are pictures of the retrofit.  It looks just like the placement of major components was designed to be configured this way!  Sometimes you get really lucky where it is important.   ;D







-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

diesel guy

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #87 on: November 21, 2007, 01:27:40 PM »
rcavictim,

Good job! It looks like that setup is reliable. I do the same things with my systems, I take three steps forward thinking everything is going good.Then I take one step back giving me results I din't want. But sometimes when you that that step back it redirrects you to a better direction and outcome. Your very addaptive with your genset and good luck.

Diesel Guy

rcavictim

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Good news report
« Reply #88 on: December 12, 2007, 11:36:14 PM »
From my first post in this thread.....

-------------------------------------------------------------begin quotation-------------------------------------------------------

Posts: 1105

   JD175 China diesel running at 500 - 1000 RPM
« on: October 15, 2007, 11:46:16 PM »
   
I have always wanted an engine that will run on the smell of an oily rag and this will be the closest I will be able to get to reach my goal.

----------------------------------------------------------------end quotation-------------------------------------------------------

Well in the language of Kelly Bundy....

Eurethra!!!!  I`ve done it!!!!!   ;D ;D ;D ;D ;D

After much testing with various belted configurations, loads and engine speeds,  I have finally achieved a sustainable mode of operation where the fuel consumption is within, in practical limits, my stated goal.  How does this sound.

0.364 litres per hour.  That is 12.36 hours on a single Imperial gallon of winter diesel.   That is 24 hours on just 2 gallons!

The engine is working hard enough that it has not fouled or wet stacked in the 20 hours of continuous test running so far.  Electrical load, four 500 watt incandescent lamps running at reduced brightness off the output of the DC gen head ( 52 VDC @ 10.50 amps = 546 electrical watts continuous).  The big flywheel is belted into operation spinning at about 850 RPM.  The engine is turning 1670 RPM.  The 1725 RPM DC gen head is spinning around 1100 RPM.  Cogen heat? Well almost no fuel in equates to almost no heat out.  :D   The coolant heat from the radiator is like a 500 watt space heater.    Since so little fuel is being burned there is not much heat from the engine and it`s impact at heating the shop is minimal, but it is at least making enough heat to maintain a clean burn and oil hot enough to do the job.  The exhaust is totally free of visible carbon or oil smoke and contains little heat as it exits the pipe fed through a temporary hole in the shop door.  Most of the exhaust heat is being radiated within the shop from the muffler and piping and therefore reclaimed.  Exhaust temp at engine is just 225 degrees F.  The engine has a 195F thermostat installed.

The efficiency is not great, but that is not uncommon with small engines.  Cost per kWh is high (about $0.70/kWh with fuel at $1/litre) but that was not the goal. The goal was a plant that could produce enough power useable to maintain my batteries in the house while in use off grid for low total fuel per hour. IMO, getting 3 hours running on a single litre of fuel qualifies as low total fuel per hour usage!   8)    When I`m finally harnessing the wind and only burning freely obtained waste oil when the wind is absent, I will be laughing. 

This power level represents 12 kWhours per 24 hours.  Can a person run a modern home full of electronic widgets on 12 kilowatt hours per day?  Absolutely, IF I can shed my electric water heater, electric clothes drier and electric stove. Solar can be used to help with domestic hot water.  Air conditioning?, not so much.  It appears that this little plant CAN power my home aircon but it needs to be in `belted to the AC gen-head mode`which adds parasitic losses and run nearly flat out to do so at ~2400 RPM.  This increases fuel consumption a lot but it is still only a 6 HP@2600RPM small diesel and at full tilt how much does that use flat out?  About 1+ litre per hour.

At this point I am encouraged because I know that more efficiency is to be had without too much more effort by replacing the very lossy V-belt drives with timing belts or serpentine, and the volumetric efficiency of the engine can be improved with a tuned air induction system. I can even look at upgrading the wound field generator to a PM gen head to pick up efficiency which is now lost to a field coil.  At this 1600 RPM speed the oil pump is working briskly and the engine gets plenty of clean oil with my added 10 micron full-flow oil filter system.  The knock stress on the main bearing, rod pin and con rod is reduced because the speed is fast enough to reduce the peak bearing loading.  I would expect a very long service life from this engine in this mode of operation.

I am pleased.  :)
-DIY 1.5L NA VW diesel genset - 9 kW 3-phase. Co-gen, dual  fuel
- 1966, Petter PJ-1, 5 kW air cooled diesel standby lighting plant
-DIY JD175A, minimum fuel research genset.
-Changfa 1115
-6 HP Launtop air cooled diesel
-Want Lister 6/1
-Large DIY VAWT nearing completion

mobile_bob

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Re: JD175 China diesel running at 500 - 1000 RPM
« Reply #89 on: December 13, 2007, 01:11:15 AM »
very good job,, i am always amazed at what can be done with the mighty little changfa
the redheaded bastard stepchild of the forum :)

(please i mean no offense to any redheaded bastard stepchildren)

i am about ready to post some progress on my project as well, changfa powered of course :)

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info