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Topics - mjn

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1
Changfa Engines / Changfa saves the day
« on: January 27, 2010, 11:29:06 PM »
Last week, my community in Northern California got hammered with 50 inches of wet sticky snow.  By the end of the storm, 9000 people were without power.   Pacific power had a huge job cleaning up the mess.  Nearly every power pole had some sort of problem.  The snow was so heavy that if the wires didn't break, the weight sheared off the cross arms.  Trees that had stood for hundreds of years collapsed (usually taking out a power line).

Fortunately, I was ready with the Changfa 195 and ST gen head.  I had the boys shovel out a trail to the generator shed that morning.  When the power went out, the Changfa fired right up and took over the job of running the lights and the pump in the well.

Previously, the Changfa was a noisy smelly beast that was merely tolerated by my wife.  All of a sudden, the ugly duckling became a sweet smelling shining beauty.   She invited all of her friends to come bask in the glory of electric lights and running water.

For many people, the power outage lasted for 5 or 6 days.  Our power was out for about 30 hours.  The Changfa ran for 22 hours and burned about 10 gallons of diesel.  This time of year, the veggie oil is all frozen, so I didn't try to thaw it out.

The sad epilogue to this outage is that in our small mountain town, there were 11 people admitted to the hospital for treatment of carbon monoxide poisoning from their gasoline powered generators.   Many people ran their generators in closed garages, or even a basement.  One man died even though his generator was away from his house, the CO was trapped between the walls of snow and flowed back into his house.


2
Everything else / Non electric overheat/overspeed shutdown
« on: April 01, 2008, 07:22:10 PM »
I have developed a revolutionary new concept for emergency shutdown of a Lister type diesel engine.  The device can be constructed from materials at hand for mere cents.
 
Functional Parts
   1. Smelly Cheese sitting on engine
   2. Mouse Attracted to smelly cheese
   3. Cat attraced to mouse attracted to smelly cheese
   4. Dog sleeping
   5. Old boot attached via string to shutoff lever of engine

Setup
  1. A piece of smelly cheese is placed on the rocker arm cover of the engine. 
  2. This in turn attracts a mouse to the engine, but due to the fact that all properly maintained listeroid engines develop a protective covering of oil and grease, the mouse is unable to climb up and get the cheese. The mouse sets up housekeeping nearby.
  3. A cat is attracted by the presence of the mouse, and sets up camp to get the mouse.
  4. A dog is kept nearby because federal law requires that cats need a dog nearby to keep them honest.
  5. A boot is attached via string to the shutoff lever of the engine.

Operation

   1. In the event of engine overheat, the cheese will begin to melt and run down the engine.
   2. The mouse, seeing his chance will come out of his hole and start eating the cheese.
   3. The cat seeing the mouse, tries to catch it.  It is a well known fact that anything within shouting distance of a properly maintained Listeroid will become covered with oil.  The mouse, having lived near the engine has a protective covering of oil which prevents the cat from catching the mouse.
   4. The cat after having been robbed of a tasty meal of mouse, begins to caterwaul bemoaning his loss.
   5. The dog after having been rudely awakened from a nap begins to bark at the cat telling him to "shut up".
   6. The wife or neighbor upon hearing the ruckus picks up a boot and heaves it at the nearest offender.
   7. The string attached to the boot pulls the cutoff lever and shuts down the engine.

The operation in the case of overspeed is similar except that the vibrations of the engine will shake the cheese so that it falls off and the procedure begins at step 2 above.

April 1, 2008 Martin Nile

3
Everything else / Computerized engine controller
« on: June 25, 2007, 08:17:42 PM »
There have been several discussions in the past about engine monitoring, and speed control.

I am in the final phases of debugging the software for my computerized engine controller.   The controler provides full automatic operation from startup to shutdown.  During operation the cpu monitors all critical engine parameters.  If anything strays out of bounds, the controller initiates an "emergency stop".

Engine RPM, water temperature, oil pressure and injector line temperature are all monitored.

Once the engine is up to temperature, the controller switches the engine to WVO fuel, and will also do a purge upon shutdown.

The final piece of the system (I'm still debugging) is a PID controller to provide accurate speed control.   The stock governor on my engine allows the RPM to sag by 100 to 150 RPM from no load to full load.  The PID controller maintains the RPM at 1800 from no load to full load plus or minus 1 RPM.

This is all implemented using a single Atmel ATMega8 cpu.  The speed control is via a stepper motor and leadscrew which hooks up to the governor spring.  The circuit is built with wirewrap and hand solder (no printed circuit board...sorry).  The software is written in 'C'.  Once I have it debugged, I'll release the full source under a BSD or similar license.

Here is a state diagram of the system operation (Click here for pdf version http://martin.nile.googlepages.com/statediagram.pdf)


I also support full manual operation of the engine.  After shutdown, the controller moves the speed control back to the normal run position, so if there is any problem (dead battery etc) the engine can be started by hand.

Here is what it looked like before I hooked it up to my engine:

I still need to implement the hour meter, and I would like to be able to change any of the runtime parameters without having to reprogram the cpu. 

You can read about the whole thing on my generator controller page: http://martin.nile.googlepages.com/automaticgeneratorcontroller



4
Other Slow Speed Diesels / Leaking injector pump -- crankcase full of fuel
« on: May 30, 2007, 12:03:47 AM »
My engine got a 5 month vacation over the winter.  This spring when I got ready to start up, I checked the oil and found that the crankcase was 2 inches over full.  There was a 2 inch layer of clear diesel floating on the top of the black motor oil.  Obviously the only way for that much fuel to get into the crankcase was through the injector pump.  I put off plans to start the engine until after I could tear into the IP to see what the problem was.

Over the weekend I pulled the IP expecting to find lots of damage.  Instead, I found a perfect pump with no obvious defects.  The pump barrel and plunger had a mirror finish with no scratches.  (There were some scratches on the tappet where it slid against the pump body which had not been properly deburred, but that is not related to my leak.)

Here is a schematic showing the insides of the pump and the suspect leak location.


I suspect that fuel (shown in red) is leaking between the pump barrel (blue) and the pump body (dark green).  This is not a tight fit.  The barrel slides into the body easily.  Under pressure, this will certainly leak. (The barrel is held pressed into place with the delivery valve nut not shown.)

The stock Changfa fuel tank is bolted directly to the top of the engine.  With a full tank of fuel, there is no more than 1 foot of fuel above the injector pump.  I have removed the stock tank and am using another tank located off the engine and another foot or so higher.  In the worst case, my fuel may be 3 feet above the IP.  I am speculating that the additional head is the cause of my leak.

Have others encountered leaking injector pumps?  Any suggestions for a fix?  I have considered RTV sealant, but I hate the thought of trying to get the goo into the right spot without getting it into the wrong spot.

In the meantime, I'm turning off the fuel when the engine is not running. (I should have been doing this anyway).

5
Listeroid Engines / Is this the cure for Listeroid Fever?
« on: January 19, 2007, 02:35:31 AM »
Today, I took a trip down to Sacramento where I picked up a Metro 6/1 DI from Fattywagonman in exchange for making my wallet thinner...


Here is my dad doing the heavy lifting during the unloading.  I've got a fair bit of work to do before I can get this running.  Hopefully John finds the governor linkage pieces in his shop.

6
Everything else / routing crankcase breather back to intake?
« on: January 11, 2007, 12:20:11 AM »
In an attempt to cut down on the oily film all over my engine, I am considering adding a tube to route the crankcase breather back to the intake.

Is this a good idea?  I'm concerned that the oily vapors could cause a runaway.  Is there something I can do to trap the oil?

7
Other Slow Speed Diesels / Changfa 195 lazy governor
« on: March 08, 2006, 07:13:48 PM »
Hi Group.

I am totally thrilled to find this forum. (I followed a link on rocketboy's site).

After drooling over a listeroid for 8 months, I purchased a Changfa 195 from Joel on ebay in hopes that it would help ease the symptoms of listeroiditis.   Unfortunately the symptoms still remain.  In the meantime, I a least have a diesel project to work on.

My engine is direct connected via a Lovejoy l-150 coupling to an ST 7.5 gen head.  So I'm running the engine at 1800 rpm instead of the rated 2200 rpm.

At no load, I set the speed to produce 61hz (as read on a kill-a-watt meter).  As I start applying load, I can hear the engine picking up and working harder, but at 3000 watts load, I'm under 60 hz.  At 6000 watts, I'm running at 57 hz.  As I approach 7000 watts I'm down to around 55 hz. At 7000 watts the engine is starting to smoke, but nothing really heavy.

The engine has plenty of power to carry the load because I can manually re-adjust the speed back to 60 or 61 hz.  The problem is that when the load drops off, the engine overspeeds and I end up making 250 volts at 65 hz.

From what I have read on George's site, it seems that the Changfa engines have better governors than the listeroids, but I would hope for much better speed regulation than what I'm seeing. 

Is this normal?  if not, what are my options for improving my speed regulation.  I'm considering a microcontroller based system to automate the generator, and it would not be too difficult to add a stepper moter to "assist" the governor, but it really seems silly.

-------------------
mjn   
Changfa 195 WVO conversion in the works

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