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| Re: [GMCnet] Onan Modernization Daydreaming [message #303417 is a reply to message #303393] |
Mon, 11 July 2016 06:58   |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Megasquirt (or even the smaller system they offer) can be used to implement several engine systems on the Onan - fuel delivery, speed governing/output frequency and ignition. A simple missing-tooth crank position sensor could be bolted on the tail shaft of the generator and would give the controller all the data it needs. Without the ability to have a cam sensor you'd still be doing wasted spark but that is not a big deal; in fact you could use Megasquirt’s to drive two coil-near-plug ignition coils - I have a couple of the GM LS2 coils for this very experiment…
There’s also electronic voltage regulation as you mentioned. This would complement the more prompt response to load that would be provided by the electronic speed control described earlier.
All of these items introduce complexity and additional failure modes which sort of takes away from the simplicity and inherent reliability of the original design. They also provide only marginal improvements in performance which may not be worth the trade-off in reliability.
—Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: Onan Modernization Daydreaming [message #303419 is a reply to message #303393] |
Mon, 11 July 2016 08:28 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Onan built an injected generator - 6 - 7KW. It used a V-twin engine with a vertical shaft, alternator mounted vertically beside the engine, belt driven. Enginne runs 2400RPM. I put one in a remote van. Instant start hot or cold, never gave trouble. Fuel pump was noisy. It ran $100 more than the same system carbureted. If you could find one, the injection system ought to transplant fairly easily. In RV service, the belt is guaranteed for the life of the system. In commercial service, 5 years. I asked the Onan guy how do you tell? If it has a commode, it's an RV.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] Onan Modernization Daydreaming [message #303442 is a reply to message #303417] |
Mon, 11 July 2016 23:37 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Jim,
Great idea to update these units.
Why cant we use the points to signal the system?
Maybe not as efficient, but simpler to install.
We have noticed great improvements on the 4k and 6k using the MSD
Capacitive Discharge as it fires twice so a complete miss fire is seldom
felt.
On Mon, Jul 11, 2016 at 4:58 AM, Jim Miller wrote:
> Megasquirt (or even the smaller system they offer) can be used to
> implement several engine systems on the Onan - fuel delivery, speed
> governing/output frequency and ignition. A simple missing-tooth crank
> position sensor could be bolted on the tail shaft of the generator and
> would give the controller all the data it needs. Without the ability to
> have a cam sensor you'd still be doing wasted spark but that is not a big
> deal; in fact you could use Megasquirt’s to drive two coil-near-plug
> ignition coils - I have a couple of the GM LS2 coils for this very
> experiment…
>
> There’s also electronic voltage regulation as you mentioned. This would
> complement the more prompt response to load that would be provided by the
> electronic speed control described earlier.
>
> All of these items introduce complexity and additional failure modes which
> sort of takes away from the simplicity and inherent reliability of the
> original design. They also provide only marginal improvements in
> performance which may not be worth the trade-off in reliability.
>
> —Jim
>
> Jim Miller
> 1977 Eleganza
> 1977 Royale
> Hamilton, OH
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Onan Modernization Daydreaming [message #303444 is a reply to message #303442] |
Tue, 12 July 2016 06:52 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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On Jul 12, 2016, at 12:37 AM, Jim Kanomata wrote:
>
> Jim, Great idea to update these units. Why cant we use the points to signal the system? Maybe not as efficient, but simpler to install.
Hi Jim,
The points can indeed be used to signal a different type of ignition system however they are quite imprecise as compared to a hall-effect or VR sensor like the pertronix or the crank/cam position sensors used in contemporary engines. Watching a timing light on a points-triggered engine versus a pertronix machine is clear evidence of this. It is also the reason that the breaker points would be unusable for electronic speed control as described in my previous message. With the points you only get one pulse per engine revolution and that pulse - when it does come every 1/30 of a second - is not precisely defined. An electronic speed control would have a difficult time maintaining a stable throttle position with only a 1 PPR reference signal to work with.
The toothed wheel I mentioned not only provides a precise once-per-rev mark for ignition and fuel injection purposes but it also provides a much higher frequency signal for the governor’s use. After all, the original post was oriented around daydreaming so I figured the toothed wheel would be a fun, multi-functional addition. Is it practical? Thats another question….
It is quite remarkable to watch a properly tuned electronic speed control in action. I’ve used ESCs from Governors America and Woodward on my gas turbines with great success. These use a VR magnetic sensor watching holes in a planetary gear carrier turning at 6000 RPM and providing a 2KHz signal at 100% speed. The particular type of turbines that I tinker with can accelerate very rapidly….scary fast…and the ESCs can nail them right at governed speed every time without overshoot or instability.
—Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: Onan Modernization Daydreaming [message #303445 is a reply to message #303393] |
Tue, 12 July 2016 07:21 |
mghamms
Messages: 466
Registered: March 2016
Location: Ware, Massachusetts
Karma: 2
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Senior Member |
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How about a 240v convention.
With all that work being done should be a simple matter.
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
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| Re: [GMCnet] Onan Modernization Daydreaming [message #303446 is a reply to message #303445] |
Tue, 12 July 2016 07:32 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Senior Member |
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On Jul 12, 2016, at 8:21 AM, Mike Hamm wrote:
>
> How about a 240v convention. With all that work being done should be a simple matter.
Its not so simple as it might seem.
Our Onans are rotating armature machines with only two slip rings to deliver their AC output. By changing the excitation system you could probably make them produce 240V but there would be no center tap neutral for 120V loads. Everything in the coach would have to operate on 240V or be fed from a step-down transformer. If you have to deploy a transformer to run most of your loads then what is the point of changing the generator over to 240V?
—Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: Onan Modernization Daydreaming [message #303450 is a reply to message #303393] |
Tue, 12 July 2016 08:35 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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The 2400/110 conversion >could< be done by replacing the alternator. Onan built the set both ways... assuming you can find a 110/240 alternator. Have you seen one of the injected models?
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] Onan Modernization Daydreaming [message #303457 is a reply to message #303446] |
Tue, 12 July 2016 10:09 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Jim,
I see what your saying.
Thanks for going over that as I felt it was not that important.
On Tue, Jul 12, 2016 at 5:32 AM, Jim Miller wrote:
> On Jul 12, 2016, at 8:21 AM, Mike Hamm wrote:
>>
>> How about a 240v convention. With all that work being done should be a
> simple matter.
>
> Its not so simple as it might seem.
>
> Our Onans are rotating armature machines with only two slip rings to
> deliver their AC output. By changing the excitation system you could
> probably make them produce 240V but there would be no center tap neutral
> for 120V loads. Everything in the coach would have to operate on 240V or be
> fed from a step-down transformer. If you have to deploy a transformer to
> run most of your loads then what is the point of changing the generator
> over to 240V?
>
> —Jim
>
> Jim Miller
> 1977 Eleganza
> 1977 Royale
> Hamilton, OH
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Onan Modernization Daydreaming [message #303495 is a reply to message #303493] |
Tue, 12 July 2016 21:13 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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Senior Member |
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mark grady wrote on Tue, 12 July 2016 20:57Thanks for the links to Wally's blog, I was click, click, clickitying around and found his post on the Wally-fied Grueninger air spring project.
Somehow, I must have missed this option until tonight, although I see that the Sully system is another branch of development of the original concept.
mark grady
northern IN | '78 Kingsley I wish I had the same tools that Wally has, and was half the craftsman he is...
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