Author Topic: Auto Shut Down  (Read 44102 times)

kyradawg

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Re: Auto Shut Down
« Reply #75 on: February 26, 2006, 02:49:57 AM »


Peace&Love :D, Darren
« Last Edit: August 03, 2006, 05:29:25 AM by kyradawg »

BruceM

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Re: Auto Shut Down
« Reply #76 on: February 26, 2006, 03:10:11 AM »
Air cylinders are available in any extension (including fractions of an inch) and diameter.  Piston area and air pressure determine force.  The 3/4" piston cylinder shown has a 1" max extension. The piston doesn't fully extend, as the lifter lever arm bottoms out against the base.




« Last Edit: February 26, 2006, 05:04:19 AM by BruceM »

SHIPCHIEF

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Re: Auto Shut Down
« Reply #77 on: February 26, 2006, 06:09:05 PM »
Bruce;
You got me looking at some Picaxe sites, and started thinking about the control issues we might want to address.
I grouped them below as SHUTDOWN, TRIM, & ALARM:

1) Oil pressure shutdown
2) Oil level shutdown
3) Water temp shutdown
4) High vibration shutdown (this would cover a host of unanticipated problems)
5) Overspeed shutdown

6)  Governor speed trim (use the governor spring, input controller to bias the spring to keep cycles closer to 60)

7) Fire detection alarm
8) High water temp alarm
9) Low oil level alarm
10) Low oil pressure alarm
11) Low fuel tank level alarm
12) Security alarm (intruders)

I was thinking that the control system should be set up so the engine can be run without it, so you can still use the engine if there is a control failure.
Also, after you start the engine, then you arm (turn on) the control system.
Oh, and then there is autostart....
This post is kind of a pull over from the bicycle computer thread...
Scott E
« Last Edit: February 26, 2006, 11:07:49 PM by SHIPCHIEF »
Ashwamegh 25/2 & ST12
Lister SR2 10Kw 'Long Edurance' genset on a 10 gallon sump/skid,
Onan 6.5NH in an old Jeager Compressor trailer and a few CCK's

Procrustes

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Re: Auto Shut Down
« Reply #78 on: February 26, 2006, 07:18:17 PM »
You might consider actuating a solenoid to drain water from the cylinder upon shutdown as well.  IIRC McMaster has high-temp solenoid valves.

Kubota tractor engines have a solenoid which must have current before the engine will start.  Possibly this is to prevent runaway situations.  If you were to take this approach, then the exhaust valve would be open by default.  This is somewhat safer, but it introduces another problem: how to start the engine without the controller?

I've long wanted to learn PIC, but I'm still stumped, flummoxed, and humiliated by my gib keys.  Maybe some day I'll be able to pitch in.

BruceM

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Re: Auto Shut Down
« Reply #79 on: February 28, 2006, 04:42:55 AM »
Bruce;
You got me looking at some Picaxe sites, and started thinking about the control issues we might want to address.
I grouped them below as SHUTDOWN, TRIM, & ALARM:

1) Oil pressure shutdown
2) Oil level shutdown
3) Water temp shutdown
4) High vibration shutdown (this would cover a host of unanticipated problems)
5) Overspeed shutdown

I plan on putting all of the shutown signals through a latch with LEDs, and then into one pin on the controller.  It saves pins and the controller doesn't care, the action is the same...stop. The latches would keep the status lights on till reset so you could quickly see the cause of shutdown.  I don't have number one...my 6/1 is splash lube only.  I will do low/high (coolant leak) oil.

6)  Governor speed trim (use the governor spring, input controller to bias the spring to keep cycles closer to 60)

I very nice idea but beyond my initial plans.  If this could be done with a hgh speed RC servo, it could be fairly cheap to implement.  I think I would dedicate an '08 chip to this function. (I think it has an analog input- otherwise the most basic '18.)  Easier to implement as a dedicated $3. chip.

7) Fire detection alarm
Good idea.  Hadn't thought of this.

8) High water temp alarm
9) Low oil level alarm
10) Low oil pressure alarm
11) Low fuel tank level alarm
12) Security alarm (intruders)

I don't plan on alarms for the first round, but it make good sence. I would also wire or them to a single pin input to the controller, and use the same status lights scheme with a yellow light for warning.


I was thinking that the control system should be set up so the engine can be run without it, so you can still use the engine if there is a control failure.

Absolutely.  Manual operations are a must. With the controller off, you should have a stock machine ready to hand start. 
 

Also, after you start the engine, then you arm (turn on) the control system.
Oh, and then there is autostart....


This post is kind of a pull over from the bicycle computer thread...
Scott E


BruceM

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Re: Auto Shut Down
« Reply #80 on: March 07, 2006, 01:54:37 AM »
I made up a little test program for the Picaxe 18x solderless breadboard today and downloaded it via USB/serial cable.  It works great!  I'm really sold on the Picaxe chips for simple control tasks.  My total "development system" cost was $19. including a nice little solderless breadboard. If you design in a header or serial connector, your prototype can be programmed without removing the Pixaxe chip. Lots of  nice, affordable picaxe stuff at phanderson.com

I've got another application for the Picaxe before I do the engine controller, but when I do it, I'll be glad to share the program here.

Best Wishes,
Bruce M











jtodd

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Re: Auto Shut Down
« Reply #81 on: May 09, 2006, 07:57:51 PM »

I'm going to go back to the earlier parts of this thread and raise some questions, since I'm still not quite sure what the consensus is.

It seems to me that the rack puller is the "proper" way to stop the engine.  It also seems to me that the engine should be "fail safe".  Lastly, it seems "simple is better."  So, I've discounted air pistons (too complicated - two more systems to manage), closing off the fuel (not instant stop), and closing off the air (maybe impossible)  I have a 12vdc system planned, so I have plenty of 12v power.  That leaves electrically operated solenoid-type rack pullers - only one more system to manage, and a well-understood one at that.

The solenoid activates and pulls the pin back X.X inches.  Then, an electromagnet (using much less power) holds the pin in place.  In my fail-safe world, what I would do is actually not have the solenoid pull the rack upon engergizing, but in fact have the solenoid close the rack on DE-energizing, by allowing a compressed spring to extend and push the rack controls closed.  Why?  So if I lose the 12v for  whatever reason, the solenoid would de-energize, the spring would be released, and the rack would be closed.  I like fail-safe for stopping engines; having to rely on a power supply to stop the engine seems a little dangerous.

This means I need probably 150% the pulling power in the solenoid that is required for just the rack, since I need to pull back the spring, which will in turn be ~125% of the required force to close the rack.

Does anyone see anything obviously wrong with this method?  It's a bit spendy (~$150 for both parts and some springs) but seems to be easy to implement.

My questions for the group:
  - what's the the travel required to close the rack on your engine?  1.5"?  2"? other?
  - how many pounds of force are required to close the rack on your engine?  15#?  20#?
  - what kind of engine do you have?  (brand and size)

I ask these questions so I can maybe come up with a "universal system" whose specifications would work for anyone's engine, and I'll post the notes here.

Some resources for people searching this thread:

  http://www.trombetta.com/DefaultFrameset.asp?ShowContent=prod
     P613-A1V12   1.5" draw, 21 pound pull, $94 from http://www.murcal.com/
 
  http://www.murcal.com/s500-a60.htm
     S500-A60 controller, reduces voltage to coils after draw but keeps hold magnet engaged $53

GuyFawkes

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Re: Auto Shut Down
« Reply #82 on: May 09, 2006, 08:25:10 PM »


My questions for the group:
  - what's the the travel required to close the rack on your engine?  1.5"?  2"? other?
  - how many pounds of force are required to close the rack on your engine?  15#?  20#?
  - what kind of engine do you have?  (brand and size)

a/ at a guess, about an inch, mebbe inch and a quarter
b/ 16 ounces is LOADS, --- 20 POUNDS will damage stuff
c/ genuine 6/1 start-o-matic
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Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

BruceM

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Re: Auto Shut Down
« Reply #83 on: May 09, 2006, 08:47:15 PM »
Jtod,
Good post and some good ideas, too.  Even I have second thoughts on pneumatic actuators. :)
The rack needs about an inch of throw, and about 15 lbs of force.  It takes this much force to overide the governor spring.  I've measured the force with a digital fish scale. 16/20 oz won't do squat.

If you look back in the thread, you'll see two suggestions I've previously made:  Giant scale RC servos have enough torque to do this and also to operate a decompression pin.  Picaxe and other microcontrollers  have compatible servo control software already done for you.  It's a Basic command in Picaxe Basic.

For a fail safe shut down, I'd suggest the fuseable brass wire method I previously mentioned. This wire holds the end of the governor spring and is disconnected by frying it with 12volts.  I've tested this and it does work nicely. This could  be used for an emergency shut down in case the microprocessor didn't operate properly, with some extra logic and timers.

But in general, I think the odds of the microprocessor failing at the same time as the cooling system or some other mechnical failure is remote enough to be resonably ignored.  Or perhaps just have the more commonly used "sanity check" pulsed circuit that the processor must keep alive, else the emergency brass wire should be blown.  So if the microprocessor fails at any time- they rack will be closed.

I have found the Picaxe chips to be easy to use, very reliable and static resistant. I'm wrapping up a project using one for a remote fiber optic controlled cell phone, just updating schematics now.  Picaxe basic is ideal for a lister(oid) controller, as it's easily readable and requires no investment in development tools.  I must thank Mr. Lister for his suggestion that I look into them.  I'm not sure when I'll get to the auto start/shut down for my Listeroid, but when I do I'll be glad to provide the source code to anyone who wants it.  Then it could be readily changed for different actuators, sensors, etc.

Best Wishes,
Bruce M





« Last Edit: May 09, 2006, 08:52:51 PM by BruceM »

Andre Blanchard

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Re: Auto Shut Down
« Reply #84 on: May 09, 2006, 09:14:12 PM »
For a fail safe shut down, I'd suggest the fuseable brass wire method I previously mentioned. This wire holds the end of the governor spring and is disconnected by frying it with 12volts.  I've tested this and it does work nicely.
This would be more fun. :o
http://en.wikipedia.org/wiki/Detonating_cord

A length tied to the injector line should work.
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jtodd

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Re: Auto Shut Down
« Reply #85 on: May 09, 2006, 10:23:36 PM »
Jtod,
Good post and some good ideas, too.  Even I have second thoughts on pneumatic actuators. :)
The rack needs about an inch of throw, and about 15 lbs of force.  It takes this much force to overide the governor spring.  I've measured the force with a digital fish scale. 16/20 oz won't do squat.

If you look back in the thread, you'll see two suggestions I've previously made:  Giant scale RC servos have enough torque to do this and also to operate a decompression pin.  Picaxe and other microcontrollers  have compatible servo control software already done for you.  It's a Basic command in Picaxe Basic.

For a fail safe shut down, I'd suggest the fuseable brass wire method I previously mentioned. This wire holds the end of the governor spring and is disconnected by frying it with 12volts.  I've tested this and it does work nicely. This could  be used for an emergency shut down in case the microprocessor didn't operate properly, with some extra logic and timers.

But in general, I think the odds of the microprocessor failing at the same time as the cooling system or some other mechnical failure is remote enough to be resonably ignored.  Or perhaps just have the more commonly used "sanity check" pulsed circuit that the processor must keep alive, else the emergency brass wire should be blown.  So if the microprocessor fails at any time- they rack will be closed.

<snip>


Thanks for the figures on the pull and throw from both you and GuyFawkes.  It seems that on the long arm of the connector (on my 12/2 JKson) that 15-18 pounds seems like the right pull, and an inch or less is about the same throw distance as I have (sorry I didn't mention this in my original post.)  Guy - where did you measure the 16 ounce figure? 

I appreciate the simplicity of the Picaxe chips, but I'm looking for something that runs without the help of solid state microcontroller devices.  I'm looking to build a system that I could understand with only what was written in marker pen above the components if I came across it with no other context or instructions.  I have big, ugly, unshielded Potter & Brumfield 12 volt relays (which can be activated or deactivated with a finger for "on-the-fly" debuggins) that I'm going to use for most switching components and I really like "fail safe" meaning that if the control system on the engine fails, then the engine stops.  Using a servo or fuse wire implies that the 12vdc system is still operational and the microprocessor is on-line.  If I have an alternator failure, it is totally reasonable to conceive of a situation where have I would have an engine that after several hours becomes "unstoppable" since the battery will have worn down from other components.  I would then have to reach in (not easy or safe on my particular design at the moment, but I could put on an extender) to close the rack by hand.  (Yes, I could build yet another circuit that detects low voltage on the 12vdc system and shuts down in that circumstance, but it seems like that's even more complexity.)

   I've only considered using a keyswitch, RPM overage, and thermostatic triggers to release the "hold" electromagnet in the solenoid and thus release the spring which would close the rack.  I'm sure other triggers could be added to this list easily enough.

  Lastly, I like the idea of opening the decompression (exhaust) valves as a stopping method, but that seems like it would require a LOT of force, and would require two actuators for my 12/2.  So I'm still leaning towards fuel rack closure as the method of choice...

JT

Jim Mc

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Re: Auto Shut Down
« Reply #86 on: May 09, 2006, 10:40:22 PM »
  Lastly, I like the idea of opening the decompression (exhaust) valves as a stopping method, but that seems like it would require a LOT of force, and would require two actuators for my 12/2.  So I'm still leaning towards fuel rack closure as the method of choice...

JT


If I were going to the trouble of implementing an overspeed shut down, I'd not use the 'rack puller' scheme.  The very fact that the engine is in an overspeed condition indicates that something has gone seriously wrong with the governor/fuel system, or maybe it's sucking oil in from an overfilled oilbath aircleaner, or a serious oil ring failure, or maybe the rack itself is somehow stuck.    In any case, it seems like a good idea to have the shutdown function through a mechanism other than the rack.  For overspeed shutdown, I like the idea of swinging the decompressors in.  For normal stopping, a rack puller would be OK.

GuyFawkes

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Re: Auto Shut Down
« Reply #87 on: May 09, 2006, 11:37:15 PM »
Jtod,
Good post and some good ideas, too.  Even I have second thoughts on pneumatic actuators. :)
The rack needs about an inch of throw, and about 15 lbs of force.  It takes this much force to overide the governor spring.  I've measured the force with a digital fish scale. 16/20 oz won't do squat.



I can assure you 16 oz is more than enough on a / my (genuine) lister, 15 lb is hellish strong for a spring powered governor, that's in the realm of hydraulic governors

surprised am I
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Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

GuyFawkes

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Re: Auto Shut Down
« Reply #88 on: May 09, 2006, 11:43:20 PM »

Thanks for the figures on the pull and throw from both you and GuyFawkes.  It seems that on the long arm of the connector (on my 12/2 JKson) that 15-18 pounds seems like the right pull, and an inch or less is about the same throw distance as I have (sorry I didn't mention this in my original post.)  Guy - where did you measure the 16 ounce figure? 


I didn't measure it anywhere, that's a guesstimate from showing the rack closed with my pinkie.

this is the start-o-matic combined decompressor and rack closer, I'd guess about 5 foot pounds of torque will operate it nicely

--
Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

Andre Blanchard

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Re: Auto Shut Down
« Reply #89 on: May 10, 2006, 12:10:24 AM »
I didn't measure it anywhere, that's a guesstimate from showing the rack closed with my pinkie.


Can't say as I ever measured it on my 6/1 but I would say it is closer to 16 ounces then 16 pounds.
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