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Steering Reservoir Tech (and Demo)
- Thread starter RadialDynamics
- Start date
Accumulators are very good at absorbing fluctuations in fluid flow (vibrations, basically) and momentarily supplementing pump flow when it can't keep up with system demands. How long that moment lasts depends on either how long the excess demand lasts or how much volume the accumulator holds.
I have seen banks of 20-30 accumulators that are the size of large welding bottles that do a very good job of supplementing flow. But I can't see a situation where one that would fit in a vehicle nicely would produce any noticable affects before it emptied out.
Maybe on a hydro assist rig where people often talk about the ram lagging behind an slowing down an emergency swerve, an accumulator could give a quick little burst for that one turn.
ParadisePWoffrd
Recovering Project Junkie
My initial thought was to have it feed the reservoir, basically as a way to supplement the fluid exchange and maintain pressure. But, as you mention, not sure how you would charge/fill that.
I know the return side of the system isnt "under pressure" but the fluid/line has to have some pressure on it, just from the ram/valve pushing it back to the reservoir. If you knew what that value was, it might tell you how much charge you could put and it still fill the accumulator. In a system where you are using a double ended ram, and the extra capacity isnt needed, Im not sure that it really buys you much, other than the pressure charge, which can be done in much simpler ways.
HYDRODYNAMIC
Rock Stacker
With open center orbitals and rear steer valves, an accumulator would only fill when steering which would slow steering, then dump through the valves once back to center. It would have no benefit.
I was talking about a low pressure accumulator for reservoir use, not high pressure.
I was talking about a low pressure accumulator for reservoir use, not high pressure.
With open center, it would actually slow down steering response because it would have to fill the accumulator and steer at the same time. Definitely not doing any good there.
The only way I can see it working on the reservoir side is with some tricky sensors. I could be way off, as I haven't really thought this through. But if you had an accumulator fed off of the high pressure side of the pump and feeding back to the reservoir or maybe even the pump inlet, you could use some check valves and fast acting ball valves run off of a pressure switch or maybe a cavitation sensor (knock sensor?) to supply the pump as needed.
Provience
Kill!
I looked into it long and hard and rugger looked in to it long and hard, despite both of us being stubborn assholes, we reached the same conclusion: not worth it.
ScottRS
Not @Rockstomper today
A low pressure bladder accumulator (I don't think a piston would reasonably work because of seal drag and the low pressures we're talking about here) on the reservoir side, with some PITA bleeding procedures prior to charging the accumulator, could work. I just don't see it being beneficial-enough over a good reservoir and surge tank, or a really-good-reservoir, to be worth what I see as substantial cost and PITA factor. I'm all for overkill (I have two fuel pumps, two PS pumps, eight calipers, on one vehicle) but there's a point where even I say "that's far enough".
DesertCJ
Name of Pheel...
Lol, frankly....I'm shocked at the lengths that are being gone to attempting to solve a problem I haven't experienced on 3 separate hydro steering setups
I'm sure if you're in the problem category, it would really suck blowing pumps left and right though. The only pumps you hear about shitting the bed are the high dollar ones for whatever reason....
I'm sure if you're in the problem category, it would really suck blowing pumps left and right though. The only pumps you hear about shitting the bed are the high dollar ones for whatever reason....
Weasel
Red Skull Member
Lol, frankly....I'm shocked at the lengths that are being gone to attempting to solve a problem I haven't experienced on 3 separate hydro steering setups
I'm sure I could round up a box of cheap ones to send to ya.
No one complains about their free pumps crapping out. I probably have 4 myself.
DesertCJ
Name of Pheel...
I'm sure I could round up a box of cheap ones to send to ya.
Don't need them, I have a brand new spare with lifetime warranties on both of them
Although I've never lost a pump to start with. Only pump I've seen take a shit was a KRC and PSC's....may have been a Howe in there somewhere? The KRC was the only pump lost in my group over...a long amount of time. I suppose the blind man is perfectly happy with an ugly wife, luckily for me
Lol, frankly....I'm shocked at the lengths that are being gone to attempting to solve a problem I haven't experienced on 3 separate hydro steering setups
I went through 6 pumps on my old buggy that ran the gammet from low buck to high dollar. On Dave's WeRock car, we went through a similar number of cheap autoparts store pumps after putting in the extend-o-shocks.
This made me pay close attention to anything I came across that could potentially solve these problems. I have come to the conclusion that most, if not all, of the problems stem from a poorly designed system. Also, most of the potential solutions are just bandaids.
I am still interested in exploring less common options, though!
Don't need them, I have a brand new spare with lifetime warranties on both of them
Possibly they were running pumps with higher flow without allowing for higher flow into the pump?
Come on DesertCJ, if it ain't broke, fix it 'til it is!
DesertCJ
Name of Pheel...
Possibly they were running pumps with higher flow without allowing for higher flow into the pump?
Come on DesertCJ, if it ain't broke, fix it 'til it is!
Word...lol. I do still enjoy reading about all this stuff though.
ParadisePWoffrd
Recovering Project Junkie
I know my setup, which doesnt give many problems currently, has a poor design, which i am hoping to change. One of the biggest issues for my rig, the PS pump is mounted high on the engine, due to frame rail clearance, and the resi is mounted on the firewall. The feed tube is plenty large, but anytime you are going uphill, the system isnt working well. Without sticking the resi out the top of the hood/cage, I dont see a traditional solution working. If I could get by with a smaller tank that sits directly over the pump, but is fed from a larger secondary source, it could allow it all to work.
On another note; I have a friend who built "tanks" into his pressure lines, on an old rig. It doesnt exist anymore, and I cant find old pictures. He was running 2 single-acting single ended rams, that were plumbed together to work correctly, with an otherwise traditional full-hydro setup. In the pressure lines he built "reservoirs" (for lack of a better term), out of pipe, that he claimed acted as a capacitor for high flow times. He mentioned that they used something similar on some paving equipment that he worked on. Not sure if they were needed or if they actually did anything, but the system worked well, running a junkyard p-pump, and the idea seemed to make sense. Any thoughts?
If he could make them himself, and maybe use some leftover parts to get it all set up on the cheap, it could be helpful (assuming he made accumulators). My main hang up with all of this is cost vs benefit. The difference in price from a cheap pump to a hotrod pump will usually be a lot less than getting an accumulator all set up.
I would love to see someone who has done it and hear first hand. I'm definitely no expert, so I could be totally wrong, lol.
Toreadorranger
Atomic Test Lab Rat
It sounds more like they are just additional fluid volume more then accumulators. Essentially just a 2nd reservoir closer to the pump. I could see that helping some if you have a restrictive feed line.
ParadisePWoffrd
Recovering Project Junkie
Yes, the pressure line came out of the pump, went into this "tank" and then went into the orbital. It was basically just extra fluid capacity, that was under pressure. Like I say, his setup, while unique, worked well, but not sure that the extra "tank" helped any. Figured I would mention it and someone more knowledgeable would know better.
DesertCJ
Name of Pheel...
I don't see how that helps at all? The pump flows what it flows. Any fluid coming out of the pressurized reservoir can only flow as fast as the fluid coming out of the pump replacing it.
AgitatedPancake
Frobot
The accumulator concept has an air pocket above the oil that gets pressurized to the operating pressure of the pump during normal use. Then if you have a sudden spike in demand that drops pump pressure due to using more volume than the pump is putting out, the pressurized air forces fluid out of this reservoir to assist with the demand. Then as soon as the pump starts catching up, it starts repressurizing the reservoir for the next spike. Just like a capacitor in the electrical world
DesertCJ
Name of Pheel...
Interesting, maybe that would do something?
AgitatedPancake
Frobot
Yeah that's what these guys are discussing. The theory is sound, but having space for components like that will be a struggle in many of our applications. But hydraulic accumulators are pretty cool tech.
Provience
Kill!
"help out hard core beaking bumps coming into the corner, to improve driver confidence"
can somebody please explain that comment to me just a little bit further?
from agitated pancake a couple posts up.
I understand this concept.
looking at their picture and trying to find anything for scale reference, they look fairly small, less than a quart for sure capacity? I'm not convinced it would be even a noticeable amount
can somebody please explain that comment to me just a little bit further?
from agitated pancake a couple posts up.
I understand this concept.
looking at their picture and trying to find anything for scale reference, they look fairly small, less than a quart for sure capacity? I'm not convinced it would be even a noticeable amount
Provience
Kill!
well, that's a bear to find comments on IG
that would be my biggest concern, the capacity, flow and pressure drop would be very rapid. looking at 1 gal accumulators were still very much undersized from a "system design" standpoint, but were at least meaningful for just a little bit longer.
with open center valves, it can't be much more than useless
Provience
Kill!
asked about volume
so followed up asking about what pressure they are running the charge at. i just can't see it being functional
not a dig at what they are doing, but improving driver confidence also comes from lucky underpants
so followed up asking about what pressure they are running the charge at. i just can't see it being functional
not a dig at what they are doing, but improving driver confidence also comes from lucky underpants
Provience
Kill!
load reacting steering valve feedback from the tires into the steering wheel buffer
that has GOT to be what they are talking about. Whew! man, this has been bugging me for a while!
at that point though, why not run a non reacting valve seems like it would lead to lower driver fatigue as well
that has GOT to be what they are talking about. Whew! man, this has been bugging me for a while!
at that point though, why not run a non reacting valve
seems like it would lead to lower driver fatigue as wellFwjeep
Active member
- Joined
- Dec 28, 2020
- Member Number
- 3180
- Messages
- 42
If you figured out what your pressure was in your system while idle, not turning, the back pressure is likely 150-200 psi.
mid you set a small accumulator at say 25psi, and it fills to 150psi, it could take up some slack in throttle lifts. Not much pressure, but flow yes. Even with open Center.
while racing your mostly going to be coming off 3500 or so rpm, 1 maybe two saws at the wheel, then back to WOT. It could make some difference. But the unpredictable nature of once it’s out, then it gets stiff, would concern me.
probably need to place a check valve between pump and any sort of accumulator
mid you set a small accumulator at say 25psi, and it fills to 150psi, it could take up some slack in throttle lifts. Not much pressure, but flow yes. Even with open Center.
while racing your mostly going to be coming off 3500 or so rpm, 1 maybe two saws at the wheel, then back to WOT. It could make some difference. But the unpredictable nature of once it’s out, then it gets stiff, would concern me.
probably need to place a check valve between pump and any sort of accumulator
Bebop
Well-known member
- Joined
- May 26, 2020
- Member Number
- 1458
- Messages
- 4,860
load reacting steering valve feedback from the tires into the steering wheel buffer
that has GOT to be what they are talking about. Whew! man, this has been bugging me for a while!
at that point though, why not run a non reacting valve
I have friends who have blown off 5000PSI rated hoses with a non-reactive valve.