Engine governors...

[WStayton]

BioHazard;

   Well, I THINK the 20 to 25 kW pretty much rules out anything smaller than a four of some description - especially if you are going to direct drive the head at 1800 rpm.

  I am going to use a 2.4 liter 4 cylinder diesel and I THINK that I should only take a max of 20 kW out of that at 1800 rpm.  I planning on having a transmission in the driveline to the 24 kW ST head that I have purchased, so if I really need the full 24 kW I can put the transmission in third gear and then have the engine at 2560 rpm instead of 1800 and get about 30 kW, which should drive a 24 kW head to full output and leave a little for Mom and the underwriters! <grin>  Or, run the engine at 80% for long life!

  One of the problems is that MOST small automotive type four cylinder engines have a torque peak that is so high that running the engine at 1800 rpm is really problematic.  The one exception that I can think of is the 2.3 that Ford used in the Ranger Truck.
From 1983 to 1985, the manual transmission version of this engine looked like:

                        HP   Torque       RPM   kW
                        79      109           3800   58.9
                        52      124           2200   38.8
                        36      105           1800   27.0

  The 1983 through 1985 engine used a Holley Weber Carb, but this engine has been used as an industrial engine, so I'm sure that natural gas induction is readily available.  And, the best part is, they made a s#!t load of them, so finding one isn't very hard.

  The torque peak at 2200 rpm is exactlywhat I have with the Mercedes 4 banger diesel, but the 2.3 liter gas engine is about 20% more powerful than the Mercedes 2.4 liter diesel.

  They did use a differnet flavor of this engine in the mustang, but those engines had a higher rpm torque peak and would be, I think, less suitable for a direct-drive generator.

  After 1985, they went to multiport fuel injection and I think converting one of those to natural gas would be a bigger production, and the torque peak edged up over the years first to 2400 rpm and later to 2600 rpm, so I think, on balance, the 1983 to 1985 engine is the best choice for a generator.

  The 1983 to 1985 engine had a compression ratio of 9.0:1, which was increased to 9.2:1 for the 1990 to 1993 and then to 9.4:1 for 1994 to 1997.  You could put the 1994-1997 pistons in a 1983-1985 engine for your use since you won't be octane constrained running on natural gas

  GM made something similar for there small pickup, but many of these small engines were aluminum and we, at Ford, always referred to them as "Throwaway" engines!  <grin>

  AMC/Jeep made a 2.5 liter 4 cylinder, but it suffers from the problem of having a high rpm torque peak.  Initially, with a carburetor, it was at 2800 rpm, but it increased steadily over the years to 3,500 finally - so I don't think it is really suitable for an 1800 rpm direct drive generator.

  There are also a whole bunch of foreign manufacturers that made various 4 cylinder engine, but these too suffer from having a high torque peak, so there suitability for a direct drive 1800 rpm generator is pretty poor.

  I don't know of anything in either three or two cylinders that generates enough power to drive a 24 kW ST head at 1800 rpm.  I am sure there are some oilfield engines, etc, but I am not familiar with them.  One of the problems with oil field engines is that when they finally let loose of them from the oilfields they are well and truly worn out.  Anything can be "restored" but engine restoration is a whole different kettle of fish. Also, the heavy iron oil field engines were much smaller production runs than anything automotive, so they tend to be pricier and there are less of them around that are ready willing and able to donate parts.

  How's that for everything you ever wanted to know about Ford 2.3 liter truck engines - and MUCH, MUCH more??? <grin>

Regardz,

Wayne Stayton

[BioHazard]

Great information, Wayne. I believe the Ford engine was brought up in a natural gas discussion a while ago. Nice to know such high compression pistons are readily available, I do want high compression to get the best efficiency I can from the natural gas.

I'm thinking about a six or even eight cylinder engine that could be run at even less than 1800 RPM, but I wonder how much fuel economy that will cost me. Am I correct that a gas engine should have it's best fuel efficiency somewhere around it's torque peak?

Then again I may go the other way and downsize a bit, I really like the 26hp Kawasaki water cooled V-twins surplus center has for about a grand. Kind of expensive per HP, but not so much when you consider it already comes with a governor...

With the "time of use" power billing plan I only have about 5-6 hours a day of peak prices, that will be the only time I want to run the generator. It's also the time of day we need a couple thousand watts of light in the warehouse. I may just end up doing the cogen for lights only, it would make wiring everything in a lot easier.

[Henry W]

I know the Ford 2.3 engine very well. It is one of my favorate 4 cylinder gas engines.
There are ways to get more low end torque out of it easily and it will not break the piggy bank. If intrested in building a torquey 2.3 just let me know.

The engine that I like over the 2.3 ford is the 1991 to 1993 Volvo B230 engine. These engines are also easy to get good low end torque out of them.

Henry

[WStayton]

BioHazard;

  I would caution you against running anything like an ex-automotive engine at a low rpm and high torque.  Cooling and lubrication have been optomized in those engines for very modest power at low rpm and if you draw way more than the designer had in mind, you are going to have to make some BIG changes to the lubrication and cooling systems.

  Yes, peak BSFC is normally pretty near the max torque rpm of the engine.  We used to get somethig called "Fuel Island Curves" that had rpm on one axis, BMEP (think torque) on the other axis and then cute little "plots" showing areas of the same BSFC.  They all have a sorta circular structure that, as the circles get smaller and smaller, you get closer and closer to minimum BSFC. The objective was to try and design a total powertrain that kept the engine as near to the minimum BSFC as possible for the maximum amount of its time in operation.  It was always an interesting exercise in "cutting the legs off of a table" until they developed some computerized methods to optomize the process.

  I'm not sure that you will find a suitable six or eight cylinder engine that will let you operate at a low enough rpm to have a power output near what you want for a price you can afford.  I have seen a Brown and Bovari (sp?) natural gas v-24 engine that was about a 36" bore and a 48" storke, that ran at 112 rpm and had a power output over five years that was something like 103% of its rated power, counting down time and everything!  But I fear that the cost of anything like even 1 cylinder of that beast would be WAY over your budget!  B&B also made a "W" configuration of that engine, where the center 12 cylinders was a natural gas engine and the two outboard banks were piston-pumps for a natural gas pipeline.  You just stuck it on the pipeline, out in the middle of the Arabian Desert, started it, and then came back every couple of months to check the oil and once a year to change the plugs.  They had four plugs per cylinder with each plug driven by a different magneto, so to change plugs, you disabled one magneto and then disabled the valves for one cylinder, changed the inoperative plug, rinse, repeat, ad infinitum, all while the engine was running at 112 rpm!!!  Starting them was also interesting - you had "peek" holes in the sorta "valve covers" and you just went down the line until you found a cylinder that was just past TDC on the power stroke and applied 150 psi air to it and you were off and running!!!  Oil pump(S) looked like a 500 gpm gear pump for a hydraulic system - everything was duplicate so you could service one while it still ran on the other!!!

  There are lots of proprietary big engines that have the cpapbility to run at low rpm, but again they are going tobe big buck and even at low rpm, I think they far exceed the power output you are looking for.

  As point of curiosity, why are you looking to run at a very low rpm?  If you run the engine at, or near, minimum BSFC, you get the best fuel economy and running slower just gives you worse fuel economy, so there is nothing, except, possibly, longevity, to be gained by ultra slow operation.

  That's how I see it, anyways!

Regardz,

Wayne Stayton

[SteveU.]

Hey Fellows interesting now you are talking engines.
I've had three early 2.3L Fords in my life: 80 Pinto AT; 80 Fairmont; and 84 Ranger PU MT. The Ranger by far was the torquiest. The other two had the duel stage Holley/Weber carbs. The Ranger a feedback controlled single barrel Carter. DIFFERENT CYLINDER HEADS!
BioH. the reason manufactures started out with 4 cylinder inline engines as the ultra fuel efficient economy models and have even evolved back to them as low RPM torque masters from V-6's is that it gives them the best balance ring/bearing drag versus oilpump/water pump loading versus power pulse (not quite yet overlap - takes a 6 cylinder) contribution on a four cycle engine.
BioH there was a follow over on the old Lister Engine Forum had a natural gas converted Chrysler/Dodge slant 6 cylinder he was 1800 RPM making 20-30 kWe with. He used to laugh at all of the fellows doing it the hard, expensive way with big, heavy oversized, limited low production, rare engines, pixilated with ultra low RPM and its problems on a four stroke.
Conversion costs can really escalate: Free-$500. engine + $800-1200. for a machine shop fitted base quality rebuild + $300-500. govenor build up + $150-800 methane mixer + $$$ for a certified gen head to be able to get grid tie approval + $$$ for housing/coupling capability + more $$$ to tie everything together just on this base unit.

My point is a friend of mine bought a 70's commercial Onan/Ford 240 CID I-6 trailer mounted gen set for the low $$$$ up in Portland, OR. Used it for a couple of years doing woodgas development  running. Resold it for the same $$$$ and it got shipped to Africa by an NGO. Governor, mixer, genhead, power distribution box all as an engineered package. He is now onto Kubota's as a commercial offering. Goggle up Kubota DG972. Mechanical governor and mixer included - very smooth and quiet. I've heard their 4 cylinder NA run but it is not KISS with all electronic integrated ignition/governor/mixer controls.

Real easy on these swamp draining projects to get 'et up by the $$$ alligators.

Regards
Steve Unruh

[Henry W]

This is why the ford 2.3 is such a good engine to work with. there is everything available to make it a 1800 rpm engine that will have peak torque at just below 1800 rpm. There are high volume oil pumps that will take care of oil pressure at those rpm's. If someone here is looking to make a gas or lp direct drive genset I would say the Ford 2.3 is one of the best choices.

Henry

[Henry W]

The older 2.3 ranger cylinder heads have smaller intake ports and a milder cam which make it a good engine for a 1800 rpm generator. There are other good choices of cams that will give good low end torque. There are adjustable cam sprockes available so the cam timing can be advanced to increase botom end torque. This is a big help by itself.

Henry

[Henry W]

Look at this!!!

http://www.microcogen.info/index.php?topic=2144.0

[getterdone]

i have a morris 4cylinder motor that was built into a generator. i acquired some years ago. it had a military type generator head on it.
i'ts water cooled and has a governor like a tractor.
i've never heard it run, it belonged to my uncle and he said the carburator  was messed up.
i figured i would put a propane kit on it.
another project.........that's all i need.

[BioHazard]

My point is a friend of mine bought a 70's commercial Onan/Ford 240 CID I-6 trailer mounted gen set for the low $$$$ up in Portland, OR.

Yeah, if I could find something like that I would be more interested. Cheap and old. Something that already has a governor. Something already just a few miles from me! 

[WStayton]

Hi. All!

  I previously advertised here, by parts number, that I had ordered a Control Unit and a stepper motor from Generac that I THOUGH would solve the problem of engine-control for my Mercedes engine-generator.

  Please be advise that I MAY HAVE screwed up!!!   In my endless efforts to buy cheap, I ordered the cheapest parts that conformed to the broad general description of what I needed.

  Following a telehone conversation of yesterday with Horsepoor, I again opened the box that the parts came in and, this time, actually opened the sealed almost opaque plastic packages that they cam e in and discovered, to my horror/alarm/surprise, that the two pieces that I had orcered would n't connect together electrically since they both terminated in a female connector!!!

  Both parts have six individual wires that come into the connector, and they are, almost, colorcoded identially, five out of six wires matching exactly and the sixth pai being different shades of the same color.

  I will call Generac tomorrow and plead for help, though the last time I talked to them, they were less than forthcoming since I intended to use the parts on an engine that they didn't endorse or use.

  In my defense, NOTHING, in any sales or other spot of the web, that I could/can find tells you how the two parts are terminated and/or tells you what the wires actaully are - even the documentation that comes with the parts doesn't tell you what wire does what with which and to whom!!  Nor does anything that I could find tell you "for controller "A", use actuator "B:", so somebody ordrering with an eye on the price of the parts would probably do exactly what I did - order the cheapest one and there is a significant differance.  The part I ordered costs about $40, while the one called for in the control unit paperwork costs about $115 - This may be yet another time when my desire to save a couple of nickels has cost me a few tens of dollars! <grin>

   Anyhow, please stand by on oirdering anything based upon part number supplied by me - at least until I can confirm wether or not there is any way to make it work.

  Sorry about the screw up!!!

Regardz,

Wayne Stayton

[Horsepoor]

I am anxious to see how Generac answers your questions. This device seems like the best and easiest solution for controlling the governor I've seen. I especially like the fact that unit senses frequency from the generator head output. What I plan to do, reservations on Waynes contact with Generac, is to add a second long and light spring next to my existing listeroid governor spring. I wonder if the step motor has the pulling power to pull the twin rack back independantly, using a second spring to nudge it to 60.x Hz seems like a good solution. If the the unit fails during operation, then my engine would just drop back to 58 or 59 Hz when loaded and 60 Hz under no load.

Oh, another concern I have pertains to throttle response. I wonder if the unit is designed for fast throttle response to handle loads in 3600 rpm engine? It could end up in some kind of feedback loop contantly over and under shooting the throttle setting depending upon how fast the step motor responds to input from the brian.

I really hope you are able to trouble shoot the wiring. I know two other people ready to order this kit unit based upon your results. Good luck and I anxiously await your next post after consultation with Generac.

[WStayton]

Horsepoor:

  Since I did contact Generac before I bought anything and they didn't want to talk to me because I was going to use the parts on some engine that they didn't support, I too have reservations about what i will get out of them . . . I'm hoping that if I just phrase the question saying that I have bought the parts and they obviously don't plug together, and can they tell me if they will work together if re-wired/re-connectored, and leaving out eveything about what iplan to use them on, MAYBE they will take pity! <grin>

  About response:  The unit has a gain and a droop control, so I THINK that response is NOT a problem, but I will ask.

  I'll advise, as soon as I know something!

Regardz,

Wayne Stayton

[BioHazard]

Finally got the keys to the new place. Ooooo....it has that new warehouse smell.   I'm tempted to build a generator that can match my full 200 amp 3 phase service....hmmmm....that's 72kw.   I have more space and more places for exhaust than I thought. Commercial gas rates too.

[rcavictim]

About Governors/Speed-Control:

 There are really two different "types" you can pick from, depending on what you want.

 If you want 60 Hz +/- 5 Hz for a 2 kW generator head, almost anythig with will work - rubberbands, screen door springs, automotive analog speed control, etc., etc.

If you want 60 Hz +/- 0.01 Hz, grid tied, you need something more technologically sophisticated.  Solid state is ALMOST mandatory in this case, because any sort of analog device has droop in that you have to be OFF of the set point in order to generate a restoring force and the restoring force for an analog device is proportional to how much you are off of the set point.Regardz,

Wayne Stayton

Wayne,

In the case of a induction generator or even a synchronous generator (alternators) always tied to the grid I'd say you could safely get away with no speed governor at all, just a set it and lock it manual throttle and just an over rev shutdown in case the set had to drop off the line if the mains went out.  As long as you size the gen head big enough that the engine will never be able to develop enough torque to make it slip (jump phase lock) magnetically you have nothing to worry about.  The mains will keep that engine running at exact phase sync and frequency.