Author Topic: Throttle governed engine  (Read 7945 times)

Offline Flyboy Jim

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Re: Throttle governed engine
« Reply #15 on: December 20, 2019, 03:22:02 AM »
Not that you'd necessarily want to do it this way, but is this an option? Set up a rev limiter at 2000 RPM. Set the idle at 850 to 1000 RPM. When you want to saw wood the throttle is advanced to full, the rev limiter kicks in at 2000 RPM, but full power is available as the load increases. I think wood chippers work this way.

Jim
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Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #16 on: December 20, 2019, 05:05:12 PM »
As with all things, the layout and development of something totally new may seem to look a bit "goofy". However, goofiness aside, the components all have to be modified and set up so it is physically possible to make and assemble them. I don't want to make any permanent changes to the twin cylinder engine, but realize that the governor may go thru some dramatic changes. At this stage of things, I have unbolted the fuel tank and set it aside, and sussed out an o-ring drive for the governor. From here I will move on to the linkage necessary to interface with the carburetor. I'm off with my grandson this afternoon to see the latest Starwars picture.

Offline Art K

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Re: Throttle governed engine
« Reply #17 on: December 20, 2019, 11:59:14 PM »
May the Force be with you!
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #18 on: December 21, 2019, 12:04:09 AM »
Art--I don't know if I have grown old and curmudgeonly, or if the quality of the Starwars movies has changed. I seen the first three in the 1970's?? and they were just wonderful. The next three that followed a few years later were just awful, and the most current three have a lot of special effects and explosions, but not much story to them.

Offline Flyboy Jim

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Re: Throttle governed engine
« Reply #19 on: December 21, 2019, 02:38:31 AM »
Art--I don't know if I have grown old and curmudgeonly, or if the quality of the Starwars movies has changed. I seen the first three in the 1970's?? and they were just wonderful. The next three that followed a few years later were just awful, and the most current three have a lot of special effects and explosions, but not much story to them.

Well count me into the world of  "curmudgeondom" as well Brian. The movies today change scenes so fast that my mind just can't keep up.

Jim
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"You can do small things on big machines, but you can do small things on small machines".

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #20 on: December 21, 2019, 02:08:57 PM »
Well, here it is in principle at any rate. The "at rest" position of the carburetor throttle is normally fully open. As centrifugal force makes the governor balls swing out away from the stem-post, the center red rod moves downwards. This causes the blue assembly to tilt about the center of the hub (which is attached to the governor body with a shoulder bolt, not shown). This rotates the vertical governor arm, which is attached to the carburetor throttle with a link, and will bring the engine down to idle speed when the balls are fully extended form centrifugal force.  So---Any load imposed on the engine will make it slow down. This means that the governor arms will move in towards the center of the stem-post as centrifugal force becomes less, swing the vertical arm, and feed the engine more gas to counteract the load and bring the engine back up to speed.The threaded handle with the spring below it can be adjusted up or down to put more or less pressure on the blue linkage to counteract the centrifugal force, which determines at what rpm the governor engages. There is more to this, but this is the basic concept to get your head around.

Offline Craig DeShong

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Re: Throttle governed engine
« Reply #21 on: December 21, 2019, 02:27:15 PM »
Your design looks good Brian.  Iíll be following along to see it put into practice.  :popcorn: :popcorn: :popcorn:
Craig

Offline gbritnell

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Re: Throttle governed engine
« Reply #22 on: December 21, 2019, 06:31:56 PM »
Brian,
Before you get too far into the design and build you might want to try starting the engine at wide open throttle. I have never had an engine that liked to start with the throttle wide open. I know that the newer lawn mowers and implements have fixed throttle settings but they also have a primer bulb to provide enough fuel with the throttle plate open.
On engines that had adjustable throttle control the cable would run to a lever which would pull a spring that was attached to the governor arm. The engine could be started with the throttle closed and then as the throttle lever was advanced it would pull against the governor arm (and governor spring) to change the engine speed.
gbritnell
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Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #23 on: December 21, 2019, 06:49:55 PM »
George--I totally agree with you. Provision will be made to allow starting the engine in the "idle" position. Haven't quite figured out how yet, but that will be part of the design. For now I'm just playing on the cad system, getting a handle on the three largest new pieces.---Brian

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #24 on: December 21, 2019, 09:19:51 PM »
There is a subtle bit of magic around that mechanical link between the governor arm and the throttle arm. It has to be a solid link in order to work and make the carburetor throttle arm move in concert with the governor arm.---But---when the engine is at rest and not running, the default setting of the governor is such that the carb throttle is wide open. These small engines are not fond of starting with the throttle held wide open. Therefore--That solid link must also be capable of being over-ridden so that when the engine is at rest and not running, the throttle arm can be held in the "idle" position so that the engine can be easily started. As I said, it is a subtle bit of magic. That solid link actually has to have a spring incorporated into it's design so that even though the governor is in the "wide open throttle" position, the over-ride can hold the throttle arm in the "idle" position. I will be addressing that issue and will post the updated solution when I get the design finished.
« Last Edit: December 21, 2019, 09:23:04 PM by Brian Rupnow »

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #25 on: December 22, 2019, 12:52:05 AM »
Well, I never said it was going to be easy---

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #26 on: December 23, 2019, 06:45:54 PM »
Well Sir!!!--This governor controlled throttled engine isn't for sissies. I've rejigged things about four times now, trying to come up with a workable plan. A great thank you to George Britnell for giving advise on this. I can build practically anything, but it is nice if you have some certainty that whatever you build is going to work. I've been trying to comprehend what George is telling me, and scouring the internet looking for information on Briggs and Stratton engine mechanical governors. What you see here doesn't show the carburetor, only the throttle lever. One exhaust stack has disappeared, but only because it was going to interfere with my linkage. I am going to have to make a different shaped exhaust for this side of the engine.

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #27 on: December 23, 2019, 10:01:44 PM »
I was hoping to turn the radius on the bottom of the governor housing on my faceplate, but it isn't going to fly. The largest radius I can turn on the faceplate is 5.625". Poohhh!!!

Offline crueby

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Re: Throttle governed engine
« Reply #28 on: December 23, 2019, 10:22:24 PM »
Use the faceplate, but on the rotab on the mill rather than the lathe?

Offline CHP

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Re: Throttle governed engine
« Reply #29 on: December 23, 2019, 10:38:31 PM »
Brian, I think you are making your life more difficult than you need. You need to control only one variable.
your spring, oe the fly ball, both at the same time.... good luck ;)
here is a video on how it's made
       https://www.youtube.com/watch?v=SSwSIA8qgR8eo on how it's made
12x36 lathe,Seig7x10 lathe, Taig lathe
9x29 Mill, Emco 55 CNC mill.......