Governor-like control system?

[fitterski]

I'm planning a snow-blower (posted elsewhere) possibly using an engine driven pump and one fan motor. I would like to devise control system that comprises 2 levers, one to set not-to-exceed engine rpm such as 2400, and another to set desired fan rpm such as 800. When the demand is low because I'm flying at 15 km/h in 2-3 inches of snow then I would want to engine to be commanded to supply just enough rpm to satisfy the load and keep fan rpm at the set value ...thence automatically modulating engine rpm as that load may vary from the cited one to crawling in 2 feet of the stuff.

Where on earth would I begin such a control design?

TIA

 

[aczlan]

I would use an add-on cruise control, JC Whitney used to sell them.

Aaron Z

 

[bigdeano]

If you get a Cummins truck engine I think they could be had with a governor for equipment use where constant speed is needed. The pump could probably be converted by an injector pump shop.

 

[fitterski]

If you get a Cummins truck engine I think they could be had with a governor for equipment use where constant speed is needed. The pump could probably be converted by an injector pump shop.

I fear what I have in mind is more complex, might require a variable volume pump, a centrifugal governor on the fan, and I don't know what else to divvy things up between the pump and the engine to serve up exactly the correct response.

 

[MossRoad]

I'm planning a snow-blower (posted elsewhere) possibly using an engine driven pump and one fan motor. I would like to devise control system that comprises 2 levers, one to set not-to-exceed engine rpm such as 2400, and another to set desired fan rpm such as 800. When the demand is low because I'm flying at 15 km/h in 2-3 inches of snow then I would want to engine to be commanded to supply just enough rpm to satisfy the load and keep fan rpm at the set value ...thence automatically modulating engine rpm as that load may vary from the cited one to crawling in 2 feet of the stuff.

Where on earth would I begin such a control design?

TIA

A long time ago there was a member here named Mark Chalkley. He bought a machine called an Earth Force. As I recall, he fitted it with a device from (I think, so don't quote me) Rexroth that would adjust the speed of the engine to meet the load required by the HST transmission. I think this is what you are talking about. Anyhow, this is one of the threads that got me looking at Power Trac machines instead of traditional conventional tractors. Its a good read. As I recall, this was a quite sophisticated machine and device, so guard your wallet.

Perhaps you can rig something a bit less expensive.

http://www.tractorbynet.com/forums/all-other-brands/7043-goodbye-kubota-hello-earthforce.html

As to your snowblower plans...

If you have an engine turning at X RPMS, and it spins a pump of fixed displacement of X cubic inches, it will put out X gallons per minute of fluid that will turn a motor at X PRMs. If you want your blower to turn at 800 RPM all the time, you need to keep that same amount of fluid going to the blower motor at all times. If you vary the engine RPMS, thats going to vary the pump speed and that's going to vary the blower motor speed. I don't think there's a way around that. You want the governor to add more fuel to keep the engine at the same RPMS and never let it variate from that RPM to maintain 800 RPM at the blower, yes?

 

[muddstopper]

Since this is the hydraulic forum, I will assume you are going to use a hyd motor to run your blower fan. If this is so, you can use a variable flow control to control fan speed. Set your engine rpms with a throttle stop. You can also get a throttle cable with a knob you just twist to adjust engine speed. It will push in for shut down and pull out for WOT and just twist the knob to adjust anywhere inbetween.

 

[fitterski]

A long time ago there was a member here named Mark Chalkley.....
http://www.tractorbynet.com/forums/all-other-brands/7043-goodbye-kubota-hello-earthforce.html

If you have an engine turning at X RPMS, and it spins a pump of fixed displacement of X cubic inches, it will put out X gallons per minute of fluid that will turn a motor at X PRMs. If you want your blower to turn at 800 RPM all the time, you need to keep that same amount of fluid going to the blower motor at all times. If you vary the engine RPMS, thats going to vary the pump speed and that's going to vary the blower motor speed. I don't think there's a way around that. You want the governor to add more fuel to keep the engine at the same RPMS and never let it variate from that RPM to maintain 800 RPM at the blower, yes?

Thanks for that link, it's a read-and-a-half but I bookmarked it and will eventually go through it all. Too bad all the old pictures and stuff are dead.

This control system is at this point way over my head, never worked with hydraulics in my life! With a mechanical setup it would be something I understand better: a certain gear & engine rpm for the fan speed and a fan-sensing governor on the engine, makes me thing of a torque converter, so that whatever fan speed I have selected would tend to maintain. Of course with most new engines being already digital there's another can of worms in there.

 

[MossRoad]

Thanks for that link, it's a read-and-a-half but I bookmarked it and will eventually go through it all. Too bad all the old pictures and stuff are dead.

This control system is at this point way over my head, never worked with hydraulics in my life! With a mechanical setup it would be something I understand better: a certain gear & engine rpm for the fan speed and a fan-sensing governor on the engine, makes me thing of a torque converter, so that whatever fan speed I have selected would tend to maintain. Of course with most new engines being already digital there's another can of worms in there.

See mudstopper's post above. Some good info there.

 

[oldnslo]

Rexroth does offer a control for their closed loop pumps that offers automatic transmission type drive where the pump will never stall the engine. It adjusts the pumps displacement based on engine RPM. I don't know if any other companies offer this type of mechanical control.

The more complicated you make this system the more stuff to go wrong.

 

[MossRoad]

I guess I don't understand why you want to re-engineer something that already exists??? A snowblower mounted on a truck or tractor, powered by either the vehicle's engine or a separate dedicated engine for the blower already exists.

Is this just a fun thing to do? If so, I'm with ya! :thumbsup:

If not, I can't sit around and watch someone poke themselves in the eye with a sharp stick.

 

[davedj1]

There is an electric governor available too. I would go that route. I don't think fan speed will be that critical once it's up and running. Just like any other hydraulic run machine, pump will vary with engine rpm.

 

[fitterski]

Rexroth does offer a control for their closed loop pumps that offers automatic transmission type drive where the pump will never stall the engine. It adjusts the pumps displacement based on engine RPM. I don't know if any other companies offer this type of mechanical control.

The more complicated you make this system the more stuff to go wrong.

I learned that from the current rig with an electrical control system, now THAT's a bonafide nigghtmarte!

That rexrot idea is interesting. Mine came from airplane constant-speed props, similar idea.

 

[fitterski]

Since this is the hydraulic forum, I will assume you are going to use a hyd motor to run your blower fan. If this is so, you can use a variable flow control to control fan speed. Set your engine rpms with a throttle stop. You can also get a throttle cable with a knob you just twist to adjust engine speed. It will push in for shut down and pull out for WOT and just twist the knob to adjust anywhere inbetween.

under that scenario i could use a controllable governor on the engine, set the engine rpm to ballpark what i need. That would pour some more coal on when tending to stall (and THAT does happen a lot). A volume control could be driven by a governor on the fan, that governor i could set for the fan speed i want. This is roughly what i'd be looking for, it's just that i've never done anything like it.

 

[fitterski]

I guess I don't understand why you want to re-engineer something that already exists??? A snowblower mounted on a truck or tractor, powered by either the vehicle's engine or a separate dedicated engine for the blower already exists.
Is this just a fun thing to do? If so, I'm with ya! :thumbsup:
If not, I can't sit around and watch someone poke themselves in the eye with a sharp stick.

First off i need 3 to 4 time the power i have, and that's the result of 8 winters experience with it. Second i want it to be so turn-key that my wife can hop into it wearing slippers and drive out to the road and back before the coffee gets cold: "snow cleared". Third, I don't want it to be an M1 tank if I can do it smaller. Small, fast, furious and no less reliable or startable than a caddy . Once I decide which way to go, that's when the going gets easy ..and fun. So far I'm just scratching my head a lot because I don't want to make a mistake that could be avoided. IF there wee no constraints I would go with a Duramax or 6bt on the rear of my Jimmy with a pump capable of exploiting 500 hp to deliver 400 to the fan. Alas it would cost troo much and the Jimmy would just collapse from the weight. That's why I want to totally explore all of the 4-5 possible avenues in one or if required two years .....before lighting the torch.

 

[oldnslo]

I learned that from the current rig with an electrical control system, now THAT's a bonafide nigghtmarte!

That rexrot idea is interesting. Mine came from airplane constant-speed props, similar idea.

For Rexroth do a search for RE92003. That is the data sheet for the Rexroth A4VG closed loop pump. The control you are looking for is called "DA" This data sheet explains it much better than I can.

We will Gladly help you spend your money.

 

[jenkinsph]

Maybe I am missing something but why bother to vary the blower speed at all? Why not vary the travel speed to match the loading? Having the blower turn fast with a light load would be much more efficient than using variable speed hydraulic pumps, motors and their controls.

 

[muddstopper]

under that scenario i could use a controllable governor on the engine, set the engine rpm to ballpark what i need. That would pour some more coal on when tending to stall (and THAT does happen a lot). A volume control could be driven by a governor on the fan, that governor i could set for the fan speed i want. This is roughly what i'd be looking for, it's just that i've never done anything like it.

You have three threads about this project, thats make it hard to follow. I looked at your backhoe blower video. The little deutz engine is rated between 24 and 110hp. Nowhere have I seen where you posted the actual hp of the engine you are currently using. Most of the 4cyl deutz engines I have seen are usually around 65hp. You keep saying you need more power than your current setup, kind of need to know how much hp you currently have before you can estimate how much more power you need. You have also thrown out several engine options you are considering going with. At any rate, I think you are seriously over complicating the whole ideal. You want a system to mount on the front of a truck with the power supply on the back of the truck. Hyd is certainly going to be the best way to achieve this. Only type of hyd system I have seen that would be similar in function to your snow thrower has been a big broom on the back of a railroad ballast regulator. the broom uses 1 1/2in dia rubber hoses to sweep rock out of the track. The broom is about 40in in dia. It uses a roller stator motor, I dont know what size. probably 11-12 cuin. If you chose to go the hyd motor route, I would suggest using a similar roller stator motor design. Without changing engines, you could use your deutz engine, if its 65hp, to run a 30gpm gear pump and have around 750rpms and 400ftlb of torques. blower output would be around 40-45hp. I have ran those 4cyl deutz engine for years, they run forever wide open and just sip fuel. The track broom is able to sweep tons of rock, and if the baffle are raised on the broom head, it will throw large gravel a long ways. Hurts like heck when one hits you too, been there and done that. I would guess that the snow would be easier to blow than the gravel. I have also tried to sweep snow with a track broom, but that dont work so well because the snow just packs against the rail. It wont bog the broom, but it doesnt get rid of the snow either. Your snow blower scrapes the snow into the big fan and blows it out.

To get any real help, you need to post a few numbers as to what kind of speed the blower needs to turn and some estimate of how much power you really need. Just posting the hp of you current engine and how much more power you think you really need would give some sort of ideal how much hp you need and how much oil you need to pump. I can tell from your video, that you are using a belt drive gear reduction from engine to blower. What ratio is the gear drive and how many rpms are you turning the deutz engine. I would forget even trying to use all those fancy controls. Waste of time and money. Use a throttle stop to set engine rpms and a flow control to control blower speed and keep life simple.

 

[fitterski]

thanks 4 the detailed reply, I moved mine to the Snow Removal forum, "Snow PUMP" thread, it's really the place for it

 

[fitterski]

Maybe I am missing something but why bother to vary the blower speed at all? Why not vary the travel speed to match the loading? Having the blower turn fast with a light load would be much more efficient than using variable speed hydraulic pumps, motors and their controls.

moved my respmse to the Snow Removal forum "Snow PUMP"

 

[fitterski]

For Rexroth do a search for RE92003. That is the data sheet for the Rexroth A4VG closed loop pump. The control you are looking for is called "DA" This data
sheet explains it much better than I can.


We will Gladly help you spend your money.

Thanks, see "Snow PUMP thread in Snow Removal forum