Air starter

[fabricator]

Slow down Fabricator,

Please let some of the more "down to earth and knowledge" people give the 2.5" theory some thought.  But if you do try it I'll buy you lunch the next time you're in Kona.

Casey

Too late I already tried it you aint in any danger of that free lunch any time soon though As for the experiment, no go for the exact reasons given in the post by Carlb, another reason to add is the fact that the engine is never in the same place when it stops, you might be two degrees from TDC, in that case you got no run at it at all.
I know they use air starters on some on lots of diesel engines including some semi tractors, but I have no idea what kind of setup they have.

[SHIPCHIEF]

Large old style engines, and big Marine engines use an air distribution valve and direct air start to each cylinder via an air start port & valve in the head.
Now medium and high speed diesels use air starters that are just like electric starters. Some use vane type air motors, and some use an air turbine. Some engines use 2 starters that run on the same ring gear.
Over the history of the internal combustion engine, nearly every imaginable starting method has been tried.

[fabricator]

My air motor is a vane type.

[LowGear]

Gezz I hate being wrong but you'd think I'd get used to it.

Thanks for the good sportsman try.

Casey

[Ronmar]

If you're going the air route, consider plumbing into the main air line a small pneumatic cylinder to actuate the decompressor.  That way you have only one valve to turn and you can keep your hands away from greasy rotating parts which is important if you want to automate or have wife/kid be able to start the engine safely.  Air cylinders are ridiculouosly cheap (surpluscenter.com) simple and reliable.  Even though I have decided to use the Toyota starter to spin the flywheel I'm still planning to use air for the decompressor and fuel rack shutoffs.  I might rig up the Gast 4AM just for grins and because it makes such a great sound, but for reliable delivery of torque when you need it most, it's hard to beat an electric starter of some sort, especially if you know you're going to need 12V for the glow plug, control system, emergency light in genny shed, etc.

Quinn

The only problem I see with this is the motor shuts off when the air holding open the decompressor does, and the engine must coast thru that first compression to get to fire.  So you would have to have a starter that can really spin the engine up.  Good handstarting tecnique is to crank up to speed, and pull hard thru that first compression stroke.  I think I want my starter to do the same thing...

[fabricator]

When I do my automation I intend to use one of these http://www.morningstarcorp.com/en/relay-driver With this relay driver you can control four relays and program them to turn on and off depending on what you want your system to do.

[quinnf]

Hi Ron,

Yes, I fully agree that I'd  like to drop the CR prior to shutting off the power to the starter.  Mebbe I'll just do it with separate switches.  Trying to keep it simple.

[edit]  Actually here's the control panel layout I'm thinking about.  I want to keep all the circuits simple with status lights that show what's working and what's not.  Trying to avoid relays wherever possible, so using toggle switches, some with guards over them, such as the field flash and generator enable/disable.  The idear initially was to mount this inside the house next to the electrical panel and genny transfer panel which is already permitted and wired in, courtesy of a previous owner.  Genny is in the groj which is about 50' from the house.  So was hoping to remotely start the 'roid as simply as possible with a minimum of circuitry. 

Still thinking about the implementation of this system, and it's likely to change before I get to Washington again to finish wiring it up and testing it. 




q.

[SHIPCHIEF]

You might try a rotary switch, like a car ignition switch.
"on" to crank, and turned farther to the traditional "start" position for compression release.
To start, rotate the switch quickly tru to the 'start" position, the compression release will be engaged before the starter can fully engage.
Release the "start" postion on the switch to engine compression, yet still keep cranking. Upon starting, turn the switch "Off".
Just a thought....

[quinnf]

Yes, that's the simplest and most straightforward solution, but for some reason I don't like key switches.  I mean, the idea of starting an 800 lb engine that puts out only 6 HP and runs slower than my car idles . . .  something about the concept of starting such an engine with a key switch just seems, well, wrong.  Another scheme involves relays or even the use of a couple of DPDT toggle switches to allow the number of switches to be reduced.  At some point, though, the complexity rises above the KISS threshold and the idea of just throwing a jacket on and carrying a flashlight out to the groj (mebbe stepping on a roaming banana slug on the way out and falling on my tailbone) and pushing a START switch while flipping the decompressor manually doesn't seem that bad.  But then, I know I can do better.  So that's where I'm at.

One scenario I was (note the use of the past tense) thinking about was for everything to be done pneumatically except the starter.  As the starter drive wheel presses against the flywheel, a finger protruding from the starter mount pushes a SPST starter switch and energizes the starter solenoid.  That should prevent the starter drive wheel doing a burnout on the flywheel. Then I keep thinking a small magnet passing near a reed switch and a relay . . . and I'm off making things more complex again.  So much complexity can be avoided by just using another toggle switch.  And another pretty indicator light.

The idea will eventually gel.  I'm in no hurry.  For now the Armstrong starter works well enough.  

Quinn

[Lloyd]

Quinn,

If I read right, you want the control box in the house..

Me thinks relays is the proper solution, they might even make it more efficient.

Lloyd

[quinnf]

Agreed.  That might be the way this turns out.  I'd like to keep everything as simple and as transparent (read: idiot proof)  as possible, so I thought discrete switches for each function would be simplest.  But once you start thinking through what can go wrong when the wrong switch is pushed at the wrong time like disconnecting the generator while it's loaded, and relays, or even the programmable relay control that Fabricator mentioned, makes sense.  I was contemplating having engine overtemp, overspeed, undervoltage, etc. protections wired into the solenoid that controls the main air valve.  If anything goes wrong, the genny relay disconnects, the air system depressurizes and springs that were held back by the pneumatic cylinders would then close the rack, fuel valve and decompressor shutting the engine off. 

q.

[fabricator]

Check this relay driver out it is programmable for almost any situation. http://www.morningstarcorp.com/en/relay-driver