Author Topic: Reduced HP / RPM. Setting up for continues run, low output  (Read 1480 times)

gadget

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #15 on: December 31, 2020, 12:43:23 AM »
I've been searching for an option for a low output CHP set, right around .5-1 HP. I'm looking for 300-600watts continues electric and heat output. Think small cabin type setup. I want it to run continues but be able to go a 25k hours between major rebuild(if possible) so I'm thinking low 100-200 RPM. Big piston / flywheel motor looks like the way to go.

So far, I'm thinking a listeroid may be the simplest setup, but I'm not sure what kind of power output at those speeds. I was also looking at a changfa but I think indirect injection would probably be more reliable at low speed vs the changfa direct injection. Its going to also run on oil.

Your looking for only 300 to 600 watts?
A listeroid is too large. It will never heat up enough. It will coke up, and cylinder will most likely glaze up with such a light load. And a gooey mess coming out of the exhaust.

If you can find an R-165  and slow it down I would think it might be a better setup. It's only rated to 3hp.
Running it at around 1800 might give you around 1.5 hp. With friction and losses in a belt setup it might get you to where you need to be.

Was the R-165 IDI? I was looking at them but info is very hard to find. I saw one on ebay go for $300

hwew

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #16 on: December 31, 2020, 01:15:14 AM »
I believe they are IDI. Im not sure if they make them in DI. I know the S-195ís were made both ways.

I think the S-165 will be the best you can find for your application.
« Last Edit: December 31, 2020, 08:38:38 AM by hwew »

veggie

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #17 on: December 31, 2020, 05:11:05 PM »

If you already have a Listeroid and need 600 watts for batteries or other electrical needs, consider loading it a bit more by also connecting your generator to a heating element in the hot water tank. Or in cooler months plug an electric space heater into it.
That may help get the operating temperatures up while helping your heating needs.    CHP  ;D
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

gadget

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #18 on: January 01, 2021, 06:05:02 PM »
I believe they are IDI. Im not sure if they make them in DI. I know the S-195ís were made both ways.

I think the S-165 will be the best you can find for your application.

Confirm, you mean the r165 Changfa correct?

If I ran it at lower RPMs, I would likely need a custom long runner intake and more flywheel mass, should not be a problem
« Last Edit: January 01, 2021, 06:07:32 PM by gadget »

gadget

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #19 on: January 01, 2021, 06:14:46 PM »
I believe they are IDI. Im not sure if they make them in DI. I know the S-195ís were made both ways.

I think the S-165 will be the best you can find for your application.

Confirm, you mean the r165 Changfa correct?

If I ran it at lower RPMs, I would likely need a custom long runner intake and more flywheel mass, should not be a problem


https://www.youtube.com/watch?v=4ATQamebvfU&t=72s

gadget

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #20 on: January 02, 2021, 05:25:00 AM »
I've been searching for an option for a low output CHP set, right around .5-1 HP. I'm looking for 300-600watts continues electric and heat output. Think small cabin type setup. I want it to run continues but be able to go a 25k hours between major rebuild(if possible) so I'm thinking low 100-200 RPM. Big piston / flywheel motor looks like the way to go.

So far, I'm thinking a listeroid may be the simplest setup, but I'm not sure what kind of power output at those speeds. I was also looking at a changfa but I think indirect injection would probably be more reliable at low speed vs the changfa direct injection. Its going to also run on oil.

Your looking for only 300 to 600 watts?
A listeroid is too large. It will never heat up enough. There is just too much iron to soaking up the heat. It will coke up, and cylinder will most likely glaze up with such a light load. And a gooey mess coming out of the exhaust. I doubt the crankcase will get hot enough to evaporate the moisture.


You know considering how cool these motors run, it occurred to me maybe they could be insulated. I went to Canada once in January when it was around -18F and my rental car never armed up. The heater barely put out any heat after driving on the high way for about an hour. I'm guessing the cold air around the motor and heater where cooling the motor to much.

What would be the implications of wrapping a listeroid in some insulation? Has anyone tried it yet? I know there are issue with the sump area staying pretty low temp

hwew

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #21 on: January 03, 2021, 04:13:27 PM »
« Last Edit: January 04, 2021, 07:09:40 AM by hwew »

hwew

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #22 on: January 04, 2021, 05:13:47 AM »
I believe they are IDI. Im not sure if they make them in DI. I know the S-195ís were made both ways.

I think the S-165 will be the best you can find for your application.

Confirm, you mean the r165 Changfa correct?

If I ran it at lower RPMs, I would likely need a custom long runner intake and more flywheel mass, should not be a problem

Yes, the R-165. You wonít need a long intake runner. Naturally aspirated diesels pull very little vacuum, especially at lower RPMís.

Your not building a 170 Hyper-Pak. If you are, then long intake runners for sure. :)
« Last Edit: January 04, 2021, 06:25:10 AM by hwew »

gadget

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #23 on: January 04, 2021, 06:49:39 AM »
Here is some info: I’ve saved more through the years, I just have to find it.

The Impact of Generator Set Underloading (Must be logged in to view the attachment)


Some other stuff

https://service.multiquip.com/pdfs/Diesel_Engine_Wet_Stacking_Prevention.pdf


https://res.mdpi.com/d_attachment/eng/eng-01-00009/article_deploy/eng-01-00009.pdf

Sorry, this is long winded;

I read both of the PDF's. I know the trucks that idle for hours at truck stops have trouble with wet stacking in cold climates.

This got me thinking about some high temperature wood stoves I have made. I built one last winter with a ceramic fiber burn box and 2 blowers. Out put was very clean. Almost zero carbon build up in the stove. Flue exhaust (2 inch PVC) is basically warm misty CO2. Pretty cool for a wood stove.

I design my wood stoves with these principles; You have your fire triangle - fuel/heat/oxidizer (O2) but I also came up with an efficiency triangle after studying thermal oxidizers - time(under heat)/turbulence/temperature. Burning fuel is pretty simple, break the fuel down to its individual atoms and combine it with and oxidizer and allow enough time. Problem is, there is not enough time in a wood stove so we an make up for it by increasing the heat. In an engine, there is pretty much zero time so its pretty much just heat and mixing(turbulence). You can actually burn a fuel at room temperature by the way. Just allow enough time and it will oxidize(burn).

So in your diesel, as long as you have enough heat, air is coming in, and your injector is spraying fuel, it should run. Problem mentioned in the articles is that there is not enough heat in low load operation and the fuel is not burning completely. Just like if you run your wood stove on low you get build up in the chimeny.

partially broken down fuels(incomplete combustion) produce smaller hydrocarbons like tars/turpins and such and when they condense and combine with carbon it forms a sticky mess. Enough of this can cause engine damage over time.

with diesels unrestricted air intake, the fuel mixture can become extremely lean under light fueling adding to the problem. The cold high volumes of air cools the fuel mix to much causing pockets of unburned fuel.

So basically, motors are designed to operate in a window but, can we move the window around. How low can that window go? They use to run motors at very low RPM years ago, I'm assuming they worked fine???

We just need to maintain the efficiency triangle at the RPM's we want to run at. Listers seem to already have issues with buildup so how do we keep efficiency up? Trap more heat in??? Up the static compression??

I mentioned wrapping the block and head in insulation earlier, Anyone have any thoughts on that????? What issues would this cause??

Great input so far!!

hwew

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #24 on: January 04, 2021, 07:23:56 AM »
Manufacturers invested lots in R&D. Most have recommended running RPMís. And loading. Itís best to stay within the manufacturerís recommended parameters. If you can stay within recommended parameters than engine life should be within the manufacturerís claims.

Another issue that has been discussed on microcogen and I think I brought it up on this fourm a while back is Critical Speed. An engine can generate harmonics that can damage itself at certain RPMís.

Lightly loading any diesel is a bad idea. If your going to run only 300 to 500 watts, consider getting a Honda GX120 engine. Honda recommended operating speed for this particular engine is 2000-3600 RPM. It puts out just under 2hp at 2000. They are very efficient and last long. Buy a Meccatle S15W-45 generator head with the two bearing kit and you can have a nice compact efficient gas generator. And you wonít have the headaches running a diesel severely under loaded.

If you want to make a some hot water fabricate a heat exchanger.

Personally, I would purchase a small inverter generator that is rated to 1000 watts. I have a Yamaha EF1000iS and itís seen hell. Fell off the back to the pickup, Used for weeks running a Sawzall, right angle drill, small skill saw, 4 blowers and halogen lighting. There were days it has ran over 10 hours on .66 gallons of gas. Been over 5 years and has hundreds of hours on and still does not use any oil. Itís one of the quietest ones out there. Noise Level 1/4 Load, 47 dBA / Full Load, 57dBA. The engine is only 50cc. During fall, winter and early spring itís all I need for my RV. One of the best investments Iíve made for a generator. Maintenance, oil changes, air filter and spark arrester screen. Thatís it.
« Last Edit: January 04, 2021, 01:31:11 PM by hwew »

gadget

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #25 on: January 04, 2021, 05:41:39 PM »
hwew,

I was digging through some of the changfa videos. Thats a nice looking little motor, to bad the ban came in right when they where getting popular. I like the dual balance shafts and gear drive setup. From what I can tell, it is partially splash lube so that would have to be checked out for low RPM operation. I don't think many got imported. There may be less of them in the US then listeroids. Im wondering if someone can import "kits". Im guessing they don't make the R165 anymore, anyone know?


For now, I think I will focus on converting a lister since I'm thinking the Changfa displacement might be to small for very low RPM range. The lister already has the large flywheels....

Lets assume for argument that a 6/1 produces 1 H.P. at 100 RPM (probably less than that). Thats 745 watts of flywheel power. If you apply a 600w load, you are now in the "heavy load" range. Assuming a 33% thermal efficiency lets say we will have 4,100 BTUs/hr waste heat. lets say we want to heat the entire motor minus flywheels from 60F to 180F. heat capacity of mild steel = .122 btu/lb-deg F ...400lbs x 120F increase x .122 = 5,800 BTUish. roughly 85 minutes to full warm up of entire block. Thats assuming no losses from surface radiation on the motor. Thats not allot of heat to work with. If we want to raise 50 gallons of water from 60F to 140F, we need 33,000 BTUs. Thats 8 hours of run time assuming zero loss from the block to the room. Thats almost a perfect match for a little remote cabin and basic hot water needs. FYI this would also involve capturing exhaust heat otherwise numbers are double for water heating time.

The block is going to need to be insulated. Now for what its worth, most vehicles I have worked on hot over the years never see 180F through the entire motor. Mostly between 120-150F on the edges and opposite ends of the motor. We don't have to keep the entire motor at full temp. There is resistance to heat flow, we just need to keep the head and cylinder/piston up to temp.

The other issue is the V.E. We will need to be getting 1.66 CFM into the motor at that RPM. There is a way to confirm this, if someone had a compression gauge and a 2 cylinder lister, they could confirm this with one side running and the other measuring running compression through the RPM band. We could graph VE through the RPM range this way. Other option is to manually spin up a single cylinder lister.

Some thing to think about, the V.E. can't be to horrible at that low of an RPM otherwise these motors would never hand start without glow plugs fully cold. Bumping the compression up may be all that is needed. The induction system may be fine how it is.

This is looking very possible from what I can see.

veggie

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #26 on: January 04, 2021, 09:03:12 PM »
gadget,

Sure, you can insulate the head.
Like this guy...
https://www.youtube.com/watch?v=V2ehdeEJOok

You can also run it slower and add a thermostat to keep the combustion temperatures high.

You can also load the engine up to 85% of the HP it creates at that lower speed, ensuring that it's adequately loaded and making as much heat as possible.

Good luck with the project, and be sure to post pictures/videos

veggie
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw

gadget

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Re: Reduced HP / RPM. Setting up for continues run, low output
« Reply #27 on: January 05, 2021, 04:15:33 AM »
gadget,

Sure, you can insulate the head.
Like this guy...
https://www.youtube.com/watch?v=V2ehdeEJOok

You can also run it slower and add a thermostat to keep the combustion temperatures high.

You can also load the engine up to 85% of the HP it creates at that lower speed, ensuring that it's adequately loaded and making as much heat as possible.

Good luck with the project, and be sure to post pictures/videos

veggie

Wow, that video was just uploaded 2 days ago, talk about timing. Glad to see someone else using insulation, hope to here back how it works. I'm thinking some rockwool with a nice sheet metal cover, it does look pretty hideous like that.

If anyone gets a chance to read the PDFs Hwew posted I recommend it. Lots of good info in there. One thing mentioned is a very lightly loaded diesel could see as high as 500 to 1 air to fuel ratio. This is a big contributor to the stacking or coaking issues. Think about this, lowering the engine RPMs down to match a light load may actually be better in some circumstances vs running at full RPM with a light load. Veggie mentioned it and I agree, matching load to RPM is something to consider. But what about bearing "lugging"? I think in a diesel it would smoke profusely before and "lugging". Anyone have any thoughts on this???? I don't think it would be a problem but thought I would ask anyway.

My motor is still disassembled in boxes at the moment. I started a new business and I don't have much free time. Right now, I'm building a new (larger) freeze dryer for the business and I don't know when I can get back to the motor. I will post pics/results once it gets going. Plus, its about 30F in my garage right now

If I do go the low RPM route, I would do a once a week full RPM / full load exercise combined with some water injection. The higher air volumes can do wonders to push out soot. We had a Mercedes diesel get stuck in full fuel once in a shop and it ran full RPM for about a minute. It left a pile of soot on the shop floor where the exhaust pointed down. The customer reported back no problems with the motor and that it ran better then it had for years. I'm not recommending anyone try this...lol



« Last Edit: January 05, 2021, 04:27:42 PM by gadget »