pfoxy, Maybe there are too many moving parts for me but I don't have quite the same "take" on things as you. Pardon me if I go on about what seems obvious but in the past, not having a common understanding before trying to move into uncharted waters has resulted in a lot more confusion than communications, so...
My understanding of the HST pedal is that it sets the hydraulic equivalent of the gear ratio (varies the stroke on hydrauic pump).
Then at that HST setting (gear ratio) you can vary your ground speed by changing the throttle, not unlike in a regular vehicle. The "cruise control" or whatever it is called in the book is a mechanical thingy that holds the HST pedal in one of several notches until or unless you: 1. depress the brake, 2. depress the HST, or 3. hit a decent bump.
Alternatively, you could set the throttle and vary ground speed by varying the HST (gear ratio).
On the Kubota L4610HSTC, I don't think there is a governor that is working to hold whatever RPM you set with the throttle while in neutral. I bought the tractor new. If their is, it either doesn't work or doesn't work the way I need.
If I have any of the foregoing messed up, straighten me out because as I proceed to build on that foundation I need the foundation to hold up.
Now for the NEW thing I want and a couple ideas on how it might work.
After market cruise control I saw has a sensor (coil) mounted near driveline where a magnet is placed. The rotating magnet induces an electric pulse in the coil each time it goes by so the vehicle speed has a pulses per unit time (sec min whatever) signal. I don't know if that is made into an analog DC level to represent drive shaft RPM or if it is a pulse rate vs speed (digital) signal. I suspect it was analog. Once set, the controller adjusts the throttle to maintain that signal.
If you replaced the DC analog signal with a potentiometer wired to the battery you could "lie" to the cruise control and tell it you were going at whatever speed you wanted to and it would either advance or ****** the throtle to try to correct the speed signal. Given this ability, we need to "make" a signal to give to the cruise control. This signal would represent, not ground speed, but engine speed. This can be achieved various ways. Put a magnet on something that rotates when the engine runs and put the sensor coil near that. Could be the fan, alternator, A/C compressor pulley, or whatever. If ballance is an issue put on two magnets, one on each side.
I'm not a super mechanical genious so I could sure use some help figuring out the throttle connection but I would try to imitate the setup that automakers use on their cruise control. I figure I don't need the disconnect-on-brake-application feature since I'm not controlling vehicle/tractor speed just engine speed. If I take my foot off the HST or dissengage the HST "HOLD" feature I am in neutral and come to a stop. Shoudln't matter much that the engine is still at "set" RPM till I turn the cruise control off.
If your tractors all have RPM holding governors, then you know why I want this. It would be a great convenience to have the tractor hold a steady RPM under varying loads.
If I am brush hogging on a hill, the tractor goes a lot faster downhill than up. I advance the throttle to hold my RPM up on the uphill run, then on the downhill run I have to ****** it to avoid overspeeding. If I am box blading and have a full box going up a slight grade and advance the throttle to keep the RPM up where it ought to be for some performance then when I dump the box I have to be reducing the throttle or RPM goes too high. If I had an RPM holding governor, I would think that effect would be elliminated or severely reduced (if it worked right). I'll check to see but suspect I don't have what I want. Many diesele have governors but aren't they used for rev limiters not rev setters?
Patrick
