auto emergency shutdown interlocks

[cohippy]

so I have a isuzu c201 with a 24Kw 2 bearing ST gen head. I am looking to utilize the temp sender (switch?) and the oil pressure sender (switch?) to create a low oil pressure auto shutdown control and a over temp shutdown control. i figure the low oil pressure is easy enough I just wire a relay with it and the fuel on/off solenoid and maybe the same with the over temp?
I had to scratch my head at if there is 0psi oil pressure how do i overcome the fuel being shut off....i figure a push button momentary switch I can hold till the oil pressure starts to come up.

any problems in my logic here? what have you done? what are your ideas?

I would also like to insert an auto control to change the engine RPMs from idle to 1850 at a specified oil or collent tempature. one that is not overridable. resone being I want to make sure the engine is warmed up before speed or load is applied to it.... this is especially important to me as i live in Colorado and ive seen just this winter -30f temps! and im impatient!

thanks

[cohippy]

really? no one has ideas?

[thomasonw]

really? no one has ideas?

I think your idea for autoshut-down is reasonable enough, and it is common to have a by-pass button to press during startup.  I know that Murphy (of Murphy Gauges) also had devices that include built-in time delays and interlocks  which will allow for start-up before 'arming' the alarm and shutdowns.  You might need to get them on EBay as I suspect almost everything is now gone electronic these days...


On throttle, there were some posts where someone had located a company that made special on/off solenoids which would allow for speed control.  You might try searching 'Throttle Control' or 'injector speed control' and see if you can get a hit.

-al-

[BruceM]

I'm not familiar with your engine so thought I'd see if someone else had a comment.

Many fuel shutoff solenoids can't handle the suction of a diesel injection pump.  I found this out the usual way.  The shutoff offered by Murphy can.

Still, if you are going to mess with the throttle, then consider a rack closer as your fuel shut down.
If the engine has decompression for starting, I'd think about using that for emergency shut down in addition.

Limiting the throttle position during warm up sounds nice and could be implemented via solenoids or RC servo.  A "warm enough" bimetal switch could be attached where desired for sensing.

Given the need for some simple timing and several sensors, I'd think you would be best off using an Arduino or Picaxe chip to do your control and interface. If even school oriented Pixace chips are daunting, I'm sure you can find some time delayed relays or PLCs to do it old school.

[Horsepoor]

The website for everything related to your auto shutdown needs: http://www.murcal.com/Catalog/Murphy

[sailawayrb]

...and if this is for emergency shutdown, there is always the CO2 approach:

http://listerenginegallery.com/main.php?g2_itemId=351

Bob B.

[cohippy]

i looked at those murphy gauges i really like them never knew a gauge with adjustable limit switches existed....that would fix both issues for temp and psi a second temp gauge would fix the issue of delayed rev up to 1800rpm. my question is what is the failure rate on these gauges? it says they are self cleaning contacts but idk i would think i would just want these to drive a relay contact, and not a solenoid load.

[tinkerer]

i looked at those murphy gauges i really like them never knew a gauge with adjustable limit switches existed....that would fix both issues for temp and psi a second temp gauge would fix the issue of delayed rev up to 1800rpm. my question is what is the failure rate on these gauges? it says they are self cleaning contacts but idk i would think i would just want these to drive a relay contact, and not a solenoid load.

We've used these on a few tractors and stationary engines running irrigation pumps and never had a problem. The oil pressure gauge always kept the fuel solenoid from opening until you pushed the bypass switch when starting. Never had a problem with the contacts not making contact. The gauges are sealed so as long as moisture doesn't get into them, I don't think the contacts would ever go bad. Maybe if you put too much of a load through them, it could cause problems, but if just driving a relay contact I would think you would be fine.
just my 2 cents...

[BruceM]

I agree with Tinkerer, the Murphy products, while expensive, are first class and can be expected to perform well at or below their rated specs.

I use one of their vibration sensing switch that I got surplus on ebay. Everything else was over my budget so I went the homebuilt method for oil level, rpm and temperature sensing.