Changfa R175 Micro Cogen engine

[veggie]

Hi All,

This weekend I finally got first smoke from my modified r175 Chinese diesel.
The Hopper cooling system was removed, and replaced with a combination "Blanking Plate" and "Alternator mount".
The alternator is a heavy duty 12 volt 160 amp Leese BLD2308 which makes 130 amps ( 1500 watts ) at 2500 rpm (which is 2000 rpm engine speed).
Holes were drilled and tapped for two water connections and two sensor ports.
I did a lot of this work last year but other things got in the way and I had not run tested the unit now.
I wired up a battery start switch/button and filled the engine block with water for a short run.
A stainless steel water drinking bottle was modified to act as a temporary fuel tank and I rigged up a bracket to attach it to the engine.

The grand plan was to create a compact unit which could be encased in a small soundproof box beside the garage.
Electric and heat energy would be directed into a 40 gal water tank via a heat exchanger and an electric element.
(I have both 12 volt and 120 volt elements so I can decide later if I want to use a DC alternator or a single phase AC generator)
Water would be circulated from the hot water tank through 3 wall mounted radiators for space heating.
The Pex is already inside my walls (terminating in the mechanical room) and the radiators are in place. I did this when renovating some walls last year.

With the engine running at 2000 rpm and loaded to 1500 watts (tank element) I could expect approx. 5100 btu/hr from the electrical side of the system and the same from the coolant system for a total of 10,200 btu/hr generated by waste veggie oil, biodiesel, or regular diesel.

Here's a couple of video's of the first test run of the bare unit. The alternator is not loaded and the cooling system is not connected.
The engine is mounted on a temporary base so that I can wheel it around.

1500 RPM
https://www.youtube.com/watch?v=_bIQhtTwkDk&feature=youtu.be

2000 RPM
https://www.youtube.com/watch?v=VULktfw6V6M&feature=youtu.be

The biggest concern is the noise that the engine makes.
If you turn up your speakers to FULL and also set the YouTube volume to FULL you will get some idea.    LOL
I went with the R175 because they do not have the gear driven counterbalance shafts that create so much noise in the larger Chinese diesels.
If I slow it down to 1500 rpm the noise drops a fair amount. I can still power the 1500 watt water tank element but I would not have enough power left to also operate my 25 amp battery charger. I suppose I could throw up a solar panel or two to keep the starting battery charged.
Regardless, this unit is still very loud and I'm not sure I can quiet it down enough for a residential area.

Need to give this some more thought  

cheers,
veggie

[Ronmar]

Well since it is a liquid cooled engine, why don't you put it in a insulated box.  That and a couple of big expansion chambers/mufflers on the exhaust, and a muffler on the air intake...

[veggie]

Well since it is a liquid cooled engine, why don't you put it in a insulated box.  That and a couple of big expansion chambers/mufflers on the exhaust, and a muffler on the air intake...

Yes, I think an insulated box is the only solution. A small space heater in the box would guarantee starts in sub-zero temps also.

[veggie]

What about continuous operation with an engine like this.
The idea was to have a cogen unit push heat into the house for the 3 coldest months of winter and try to make a serious contribution to space heating.
(The 500 liter waste veg oil tank would be heated and indoors).
I have a controller capable of performing stop/start operation with this small diesel and it can cycle the engine (and the whole hydronic system) according to the temperature in the house and the water storage tank. Theoretically the system could run autonomously as needed to provide heat.

Option one:
Run the engine continuous for the 3 coldest months of winter and have the control system divert extra heat to a head dump (external rad).
(That's 720 hours per month which sounds a bit excessive since an oil change would be needed every weekend)

Option two:
Stop/Start the system based on internal room temperature. Use a wide deadband in the temperature logic to prevent rapid cycling.
For example, the engine would run for a few hours and be off for an hour.
On very cold days the ON cycle would be longer than warmer days.

In any case, the engine would get a lot of hours in the 3 months of winter when the system is activated.
Any opinions on whether these types can handle lots of hours for 3 months before a spring dismantle and decoking.??

Any suggestions for modifications to ensure it survives 3 months of winter running in a 60% on, 40% off duty cycle ?? (in a heated shed enclosure).

veggie

[Carlb]

Since all of your energy both electric and heat are going to heating water, why bother running an engine at all.  A waste oil burner, babington or other heating water would be a better use of your fuel and be very simple and need very little maintenance .

[veggie]

Since all of your energy both electric and heat are going to heating water, why bother running an engine at all.  A waste oil burner, babington or other heating water would be a better use of your fuel and be very simple and need very little maintenance .

Hi Carlb,

Many reasons...
1] My interest is in co-gen
2] A diesel co-gen gives me options for diverting the electrical power to other things if needed (emergency). With multiple fuels.
3] I already have all the components for the cogen.
4]The dwelling is already pre-plumbed for hydronic heating and the location for the cogen/heat source is 15' from the house (Detached garage)
5] Building a burner and then adapting it to heat a dwelling 20 ft. away would be difficult. Transferring heat to the hydronics would be difficult, and buying a new burner  is very expensive.

All,
I wonder if the weak spot on these small engines is the lube oil capacity?
Perhaps a remote lube tank with circulation and filtration would greatly enhance the ability to run for extended periods??


veggie

[Ronmar]

I agree it dosn't make a lot of sense unless you are actively employing the electric power while harvesting the heat.  But I do understand having to get systems operational before you can expand.  the good thing about hydronic heat is that you can heat water in a bunch of ways, so integrating a boiler(wood, oil, pellets) or solar is not a great leap, it just takes time(and a little money:)).

[mobile_bob]

i will try to get some pictures up as well

iirc it was last winter that i started pretty much the same system you are working with
being the r175/alternator/ (and an A/C compressor)

yes even these little buggers are noisy

here was my design thinking, not sure if it helps with your thinking or not, but fwiw

i set it up to run on one serp belt which couples the alternator, the a/c compressor and a modified liftgate motor w/electric clutch for electric start.

i fitted a smaller version of my exhaust heat exchanger, which also reduces exhaust noise most notably.... the intake i just extended and fitted a round filter element for testing, and the noise from there is most significant.

the ignition timing in my opinion, might benefit from a couple degree's of retard, most especially given reduced engine speeds and the benefit of noise reduction... they knock a bit less loudly with less advance.  this is something i want to explore a bit more.

the design thinking for this unit is more of a topping cycle sort of thing, in that it will only be called on to run when there is sufficient demand to warrant its operation.

what i want to explore is this....

batteries are quite expensive, at least proper deep cycle units are.
what i am wondering is perhaps one could use automotive batteries, "if" they were called upon to only provide for certain loads for very limited amounts of time. what i mean by that is the automotive battery would not be asked to deliver over 5% of capacity (preferably less) basically covering the loads long enough for the system to startup, warmup and come on line to cover the load and while doing so also put back what it took from the battery bank.

of course the waste heats (coolant and exhaust) harvested for use with either domestic hot water production or possibly for space heating supplement.

as for engine preheat for cold starting, my thinking is to start the taco pump that transfers heat from the water tank so that some of that stored heat can be used to preheat the engine. i am also thinking that an electric oil pump might be useful to precharge the engine oil system so that reduced cold start wear might be had.  the little electric lube pump need not run long so its electrical needs are low.

i think the little engine could benefit from additional oil capacity, and might be accomplished via a saddle tank and a balance tube between the tank and the crankcase?  more oil ought to extend the change intervals?

again it is just sad we can't get more of these engine's into the hands of guys that would work with them... in my opinion an efficient system could be made from the r175... whether continuous operation or intermittent.

bob g

[vdubnut62]

While I don't have experience with an R175, I do with an S1100. I may be way off base, but it seems it would be a simple matter to simply cut the oil pan, weld in a band to extend the sump and drop the oil pickup the corresponding amount? I did this once upon a time to a small block Chevy.
Ron.

[veggie]

While I don't have experience with an R175, I do with an S1100. I may be way off base, but it seems it would be a simple matter to simply cut the oil pan, weld in a band to extend the sump and drop the oil pickup the corresponding amount? I did this once upon a time to a small block Chevy.
Ron.

Hi Ron,

Unfortunately the 175's don't have a removable pan. The sump is part of the block casting.

However, in this picture you can see two lines coming from the side of the block on this R175 micro-cogen unit.
My engine (and I assume MobileBobs's engine) has a cover plate where these lines connect to the engine.
Bob, do you know what's behind the plate ? maybe an oil pump ?

Here is the video
https://www.youtube.com/watch?v=KPauCLythyQ&NR=1

Here's a pic of the oil lines.... click to enlarge

[Ronmar]

You could maybe do the larger sump externally.  You add an overflow type drain to the existing oil sump that only drains away oil at the normal full oil level.  Then you add an external tank below that level with a very small volume pump.  The external sump pumps oil into the engine and as the oil level reaches the overflow it drains back out to the external sump. If you added the inlet port at that same full oil level that would remove any danger of emptying the sump accidently.  Basically a continous remote oil change:)