listeroid expected temperatures

[mike90045]

What would be the expected temperatures of the following parts, in a well running, loaded listeroid ?
  I've gotten the thermostat installed and apparently functioning in mine, and I'm still not seeing any noticeable
increase in the following areas:

head next to the injector
COV plug
head next to the exhaust port
ex pipe 1" from the head
top of cylinder jacket
bottom of cylinder jacket (not at the inlet)
crankcase access door

  I use a harbor freight IR thermometer.

Highest I could get today was 330F on the Ex pipe 1" from the port on the head.  The whole head heats up to about 170F give or take, and the COV plug is a bit hotter.   The outlet hose stays cold, then when the thermostat opens, it heats up, and I get a well stratified coolant tank, that feeds ice water into the cylinder jacket, and boiling water coming out of the top.   I've tried stirring it a couple times with a stick and eventually got the temps to stabilize about 80F (really cold day here)  but I've never gotten the crankcase up to 100F .  I've got the generator loaded to about 2200 watts, according to the metering on my XW inverter, which should be + - 5% or so.  I've got to fiddle with the Gen support and AC2 Breaker size settings to get a little more loading of it, somewhere in the 2500 - 2800 watt ballpark, now that I replaced a bad breaker in my generator panel.

  But I'm wondering why the temps are so low, or is this just where these things run ?

[sailawayrb]

Hi Mike,

In OR and won't be near my Seattle 6/1 for another week, however, those temps seem very close to what I recall once measuring with my HF IR temp gun.

Bob B.

[veggie]

Mike,
The issue may be coolant volume.
At 2200 watts your engine rejects approx. 7500 btu's/hr

Assumptions:
- Cooling tank is a 45 gallon drum
- Engine is making 7500 btu/hr
- stating coolant temp 50f (you stated it's very cold)
- Max coolant tank temp 195f

To heat that volume from 50f to 195f with 7500 btu's/hr of energy would take 404 minutes or approx 7 hours.
And that's assuming no heat losses in your piping and through the walls of the barrel.
In reality you may have to run the engine for 12+ hours to get to 195f where she starts steaming water off the tank.

For the first several hours of running you will experience relatively cold water returning to the engine.
Not sure if this is the most efficient way to run the diesel.
I prefer to get the engine (and coolant) up to running temperature ASAP for two reasons [1] Efficiency/Fuel economy, [2] Lower carbon deposits.

Assuming both your coolant hoses are in a gradual upward slope and the diameters are adequate, there's not much more you can do other than insulate the tank and hoses to reduce heat loss and enable faster warmup thereby allowing the heat rejection to dissipate through the top of the tank as desired.

Something else to consider. By insulating the tank, it may also retain heat overnight, ready for the next run in the morning.
So you may only have to do a 12 hour run just once to build up some heat inertia in your system.

good luck.
cheers,
veggie

[mike90045]

My "tank" is a converted 18 gallon gas tank, stood up on end.  Starting temps are low 30's, maybe upper 20s.  At 22F, it took me 3 compression strokes before it fired (50-50 dino & bio diesel).  And in 2 hours when batteries were charged, tank was mid 80's

When I had the head off for leaking head gasket, it was pretty loaded with wet carbon, in about 50 hours running time.

So the other thought is to skip the dead simple thermosiphon, and go heat-ex route.  Any success with passive circulation/thermosiphon running a heat-ex or radiator, or would I need pump and fans (more things to fail)

[veggie]

Passive (Thermosiphon) circulation thru a radiator works very well.
You will most likely need an automotive 12 volt cooling fan with a temp switch (I use a snap switch mounted to the upper tank of the radiator) because of the low amount of thermal mass in the cooling system and for days when the ambient air is not enough to get rid of your heat. My fan comes on at 180f.

Ronmar has had success with passive circulation through a heat-X.


veggie

[veggie]

BTW...
You noted that the crankcase temp was below 100f...
Don't expect to get much heat generated in the crankcase.
The crank is a long way from the cylinder head on these engines and very little heat is generated in the crankcase itself.

veggie

[Ronmar]

Your temps sound pretty cold to me.  That is the problem with tank cooling, even with a thermostat, the large volume of very cold water will still cause it to breathe/gulp cold water from the bottom of the tank.  The quick fix for this is to add a valve at the bottom of the tank back to the cylinder to restrict the flow.  The goal being that you restrict the flow enough to allow the thermostat to get warm enough to open and stay open at some percentage and modulate a flow that will maintain a steady 195F flow thru the thermostat.  The drawback, is that as the tank temp increases, the flow thru the valve may not deliver the flow necessary to maintain 195, and the thermostat will be wide open and the coolant in the engine will start to boil.  So it needs to be checked on every now and then as it warms so the valve can be adjusted to a range that the thermostat can modulate.  After playing with it a bit, you may find a single setting on the valve that will allow the thermostat to do it's job without reaching 0 or 100% open.

I think Veggies heat estimates are a little conservative.  I have measured the heat output from the cooling system of my 6/1 and at 2KW of electrical load, it outputs right around 12,000 BTU/HR.  At 3KW, it delivers just shy of 18,000 BTU/HR.  30 gallons is 240# of water.  so about 50 degrees of temp rise per hour at 12,000 BTU/HR.  But batteries absorbtion rates change, I am guessing that 2200W of electrical load is a moving(decreasing) target as the batts take a charge?

A radiator will thermosiphon just fine as long as the core tubes in the radiator are vertical, and of course the rad remains completely full.  This sometines requires the addition of a vent port at the highest point at the system with the expansion tank connected above this point. On some radiators this is as simple as removing the center flapper/check valve from the radiator cap.  The beauty of a radiator is that it has a lot less mass, so it flows slower at a rate more appropriate for the thermostat to modulate.   You can also put on a fan appropriate to the load.  A heat exchanger can be setup thermosiphon also.  The issue is with some heat exchangers is their very low coolant mass.  My small flat plate heatex had to be put 30" above the head to flow properly at full load.

I have been sick the past 2 weeks, and I am past due for a run of my 6/1, so I will fire it up and put on 2KW load and take some temp readings at the places you mentioned.  I typically only really measure at one location on the side of the head between the intake manifold and the COV plug.  At that point when loaded and up to temp, I measure right around 195-205F depending on the load.  I see these same temps at the outlet pipe...  I forget the exhaust temps at 2KW load, but I know I have seen 600F at 3+ KW of electrical load on the generator.

[veggie]

Ronmar,

I am wondering about your value of 12,000 btu/hr at 2kw load.
After looking at my numbers again, I would suggest that the heat outputs falls somewhere near the middle of our two values or ~10,000 btu/hr.

Why ? ....

- Lets base the output on 2kw electrical load.
- 2kw elec output equates to approx 4HP at the engine.
- 1HP = 2544 btu/hr
- 4HP X 2544 btu/hp = 10,176 btu/h  

Assuming losses for the engine follow the 1/3....1/3....1/3 rule of thumb, the heat loss from the cooling system (and the exhaust ) should be very close to the HP output of the engine.
Again this is base on a rule of thumb, perhaps your actual test results show that our Listeroids follow a slight variation to the 1/3 rule.

Ronmar,
+1 for your statement about engine loads decreasing as the batteries charge up.

Mike, you will be faced with a constantly decreasing engine load (and heat output), hence the requirement for better coolant temp management.

cheers,
veggie

[mike90045]

engine loads decreasing as the batteries charge up

Actually, the XW charger (running off the generator) the load appears to INCREASE, as the batteries fill up, their voltage rises, but the charger keeps the current at the same 35A.  As it starts at 47V, that's only 1645w, but as I hit 65V, it's ramped up in power, to 2275 watts. (charging a NiFe battery bank, I have a huge swing, the solar takes it up to 67V, but the XW won't go that far).

Apparently, I should have run 10g to the battery shed, instead of 12, for my 240VAC feed.  Then I could have put larger breakers in (30A) and be loading things more suitably...  (Just 20' to pull new wire in, and a couple breakers)
http://www.naffainc.com/x/CB2/Elect/EHtmFiles/Table310-16.htm   ( ampacity of romex )

I've still got room to play with the Generator Support setting in the control module, and since I'm at 1400 feet of elevation, I'm not going for a full 3Kw on the 6/1

Mike with the weird gear.   

PS  anyone have a recommended setup of radiator, electric fan and thermal switch that works well ?

[glort]

I think any car ( or Bike) radiator would do as they would be so overkill for this application.

I used a Subaru Liberty Radiator turned sideways so the cores are Vertical.
This is connected to the engine from the top of the motor via a 4ft log run of 3/4 inch hose at about a 45o Angle to the radiator inlet.  The hose has a T at the top which runs up to a 25L drum I use as a header tank. It was what I had and was convinent even if overkill.  The system runs at no pressure. On the other side of the T, the hose runs down a few inches to the top of the radiator so the outlet to the header tank is always the highest point.
The system seems to thermosyphon very strongly, more so than I would have expected.

The radiator came with the 2 thermo fans. Running even 1 on 12V will reduce the water temp at the bottom to ambient.  I used a tail light as a resistor to slow the fan down but I think something around 5-10W would be better. You could use a 2 pole switch for summer and winter settings with different resistances to speed up or slow down the fan.  I would far prefer a slow running fan that covers a broad area of the rad than small computer fans but people report success with them so whatever works. Cold here however is not a problem so a larger fan is always better.

[Ronmar]

Veggie
  You would think that, and your math looks sound, but those conversions are a little generic and the reality is a little different.  It does follow the rule of thirds pretty closely when compared to the ammount of fuel burnt for a given load.  For my testing I was feeding the heatex from a drum that was at the 68F ambient temperature.  The thermostat on the output of my heatex modulates the flow to deliver a pretty steady 120F water output stream.  At 1KW of electric load, it outputs 1/4 GPM. at 2KW it flows at 1/2 GPM and at 3KW it flows 3/4 GPM. These flow rates were determined with a stopwatch timing the fill of a 5 gallon bucket.

70F to 120F is 50F temperature rise. 1/2GPM is 4pounds of water per minute @ 50F rise = 200 BTU/MIN X 60 minutes = 12000 BTU/HR.   I have run this test a few times at different loads so I am very confident in the numbers.

I ran my 6/1 for a while at load yesterday and took some temp measurements with the IR. This was after about an hour at 2KW to let things stabelize.  Temp at startup was in the upper 40's. 

COV plug 245F
Side of head between COV and nearest head nut(just left and up from COV plug) 193F
Outlet elbow 193F
Top of cylinder 100F
Bottom of cylinder 83F
Inlet fitting 83F
Crankcase below cylinder 80F
Exhaust 1" from head where pipe meets peppercan muffler  394F

[mr.fixit]

I found a new radiator on amazon for less than $30.
Look in the automotive replacement parts section,and narrow the search to the 70% off items. It might take some searching. They must discount them deeply if they sit there to long.
The one I got fit a Honda Accord but most any of them would work with a little tinkering.
I also got an electric fan pretty reasonable.
Amazon also carries a hayden electric fan switch that is adjustable.

[veggie]

Ronmar,

Interesting....
I was always suspect about the 2HP/kw rule.
It's a bit "loose" as a rule.
If we simply consider 2.25HP/kw, then 12000 BTU's seem to fall in line.
In any case, it's good to get actual data to base future discussions. Thanks for that.

BTW... do you recall what you BTU output was at 3kw load ?

cheers,
veggie

[Ronmar]

Even the smallest auto radiator(geo metro, honda CRX, Prius) is going to be way overkill for a 6/1 or 8/1.  An actual electric auto fan is going to also be way overkill.  A couple of 4" 12V computer fans ziptied to the radiator to pull air thru will be plenty.  Heck a single one with a shroud to force it to pull air thru the whole radiator would probably move enough air to cool a 6/1.  With multiple fans, You can add fans to reach enough cooling airflow to match the load.  Too few, it will run over the thermostat temp at the outlet fitting.  Too many fans and the temp will cycle at the outlet elbow as the engine gulps overcooled radiator water.  Computer fans are low current draw, very reliable, and running full time have no switches to fail...  

Veggie
  I actually agree with the 2HP per KW rule for sustainable power generation.  It accounts for generator efficiencies at a engine power loading that is maintainable long term.  If you look at the HP to KW output ratings of commercial gensets, you will find this rule followed almost everywhere.  A 15KW genset has a 30HP engine.  About the only place where you start to see deviations from this are with vary large scale generator sets.

At 3KW of electrical load, the flow from my heat exchanger was marginally less than 3/4GPM.  At 50 degrees of temp increase and just shy of 6# per minute it came out to around 17,900 BTU/HR by the numbers if I am recalling it correctly.  At 1KW of load it was slightly over 12,000 BTU which goes along with my fuel consumption measurements.  The engine is more efficient loaded and uses slightly less fuel per KW at 3KW load than it does at 1KW of load.

[mike90045]

Finally got my notes to the computer -  (temps in Fahrenheit)

head next to the injector 180f

COV plug  203

head next to the exhaust port 184

ex pipe 1" from the head  307

top of cylinder jacket  174

bottom of cylinder jacket (not at the inlet) 93

crankcase access door  72