From my first post in this thread.....
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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!!!!! 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.
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!
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.