Can hydraulic systems replace ebikes in power assisted cycle

[Tabaristiio]

Instead of an electric motor, can it be substituted with an hydraulic force / power amplifying system instead?

If yes, how would it work? Could chains still be used?

Instead of an electric motor powering the hydraulic system, could the rider power the hydraulic system through force / power application whilst pedaling?

 

[JBA]

A hydraulic pump plus motor combination is less efficient than a chain and sprocket drive and therefore of no benefit to the rider. An electric motor assists the rider by delivering energy stored in the battery and therefore reduces the riders energy requirement.

 

[Baluncore]

Instead of an electric motor powering the hydraulic system, could the rider power the hydraulic system through force / power application whilst pedaling?

Variable ratio hydraulic motors and pumps are expensive and inefficient compared to roller chain drives.
Electrical DC to DC converters are light weight and efficient.

The storage of energy in a hydraulic accumulator is bulky and heavy compared to electric batteries.

 

[russ_watters]

Instead of an electric motor, can it be substituted with an hydraulic force / power amplifying system instead?

There is no such thing as a "power amplifying system". That would violate conservation of energy.

 

[Tabaristiio]

There is no such thing as a "power amplifying system". That would violate conservation of energy.

I was referring to a system where the motor multiplies the force exerted by the user on the pedals, thus multiplying input speed too.

 

[Baluncore]

There is no such thing as a "power amplifying system". That would violate conservation of energy.

True. Power is torque * RPM. Gears are equivalent to a transformer that adjusts the ratio of torque to RPM, while maintaining power, = energy flow. What is really needed is an impedance matching system that efficiently optimises power generation by the cyclist and delivery to the drive wheel.

A cyclist operates most efficiently at a particular cadence and pedal force. With hydraulics, a fixed volume per revolution pump could be used. The hydraulic fluid would then drive a variable ratio motor. By controlling the motor ratio, the hydraulic pressure would be regulated at a point set by the cyclist. That maintains optimum power generation and transfer, while adjusting for road speed and slope. Power variation would be by quickly adjusted by changing cadence or more slowly by changing the pressure setting.

The requirement that the system be efficient really precludes hydraulics. An electrical system would be more efficient than hydraulics. But roller chain with selectable sprockets and a derailleur is simple, and more efficient than electricity.

 

[russ_watters]

I was referring to a system where the motor multiplies the force exerted by the user on the pedals, thus multiplying input speed too.

Power is torque (force) times speed. If you get more out than you put in, that's a violation of conservation of energy.

 

[anorlunda]

The requirement that the system be efficient really precludes hydraulics. An electrical system would be more efficient than hydraulics. But roller chain with selectable sprockets and a derailleur is simple, and more efficient than electricity.

I don't dispute what you say, but I can't help thinking of the video of this year's America's Cup Races. They replaced the old direct drive winches with hydraulics. They must have given up some efficiency. What benefit could they gain in return?

1. Energy storage: Crew members (when they get the chance) manually crank the hand wheels to store energy in the hydraulic accumulator. The energy is used later when needed. With a direct drive, power must be supplied in real time.
2. Multi-station generators. Multiple hand cranks allow multiple crew members to generate energy to be stored.
3. Centralized command and push-button application of power. The helmsman had buttons on the steering wheel that commanded sail and other boat adjustments utilizing the previously stored energy.

It is hard, but not impossible, to imagine similar benefits on a bicycle. Perhaps a multi-rider bicycle could be closer to a yacht. Instead of coasting downhill, the cyclist could store energy to help going up the next hill.

It would be a fun project to design a car for city traffic that uses a more-or-less constant power engine plus accumulator. Power generation could be levelized while the vehicle goes up/down/accelerate/decelerate. The accumulator and drive motors could be hydraulic or electric.

It would be even more fun to watch a Tour de France where the cyclists could store/release energy on command. They could use their own stored energy to put on a burst of speed to pass the pack. If that existed for all competitors, how would race tactics evolve? Of course, the accumulator+motor must not be very heavy if used in racing.

 

[JBA]

It would be a fun project to design a car for city traffic that uses a more-or-less constant power engine plus accumulator. Power generation could be levelized while the vehicle goes up/down/accelerate/decelerate. The accumulator and drive motors could be hydraulic or electric.

The new Renault EV cruise control uses its regenerative braking system in just such manner, no added system(s) required.

 

[russ_watters]

I don't dispute what you say, but I can't help thinking of the video of this year's America's Cup Races. They replaced the old direct drive winches with hydraulics. They must have given up some efficiency. What benefit could they gain in return?

1. Energy storage: Crew members (when they get the chance) manually crank the hand wheels to store energy in the hydraulic accumulator. The energy is used later when needed. With a direct drive, power must be supplied in real time.
2. Multi-station generators. Multiple hand cranks allow multiple crew members to generate energy to be stored.
3. Centralized command and push-button application of power. The helmsman had buttons on the steering wheel that commanded sail and other boat adjustments utilizing the previously stored energy.

It is hard, but not impossible, to imagine similar benefits on a bicycle. Perhaps a multi-rider bicycle could be closer to a yacht. Instead of coasting downhill, the cyclist could store energy to help going up the next hill.

It would be a fun project to design a car for city traffic that uses a more-or-less constant power engine plus accumulator. Power generation could be levelized while the vehicle goes up/down/accelerate/decelerate. The accumulator and drive motors could be hydraulic or electric.

It would be even more fun to watch a Tour de France where the cyclists could store/release energy on command. They could use their own stored energy to put on a burst of speed to pass the pack. If that existed for all competitors, how would race tactics evolve? Of course, the accumulator+motor must not be very heavy if used in racing.

I meant to look into the rules, but 8m going to guess they used hand and pedal power for "purity" reasons; a sailboat should be powered by wind and controlled by people, period.

Or do you mean why hydraulics instead of having people crank to charge batteries and then use servo motors? Probably the same reason you use hydraulics anywhere; massive force at low actuation speed.

 

[anorlunda]

The new Renault EV cruise control uses its regenerative braking system in just such manner, no added system(s) required.

Sure, regenerative braking has been around for decades. But regenerative brakes can't store energy while waiting at a red light. Think of a hybrid vehicle like the Prius. Think of a non-conventional source like a Stirling engine.

Stirling engines can run directly on any available heat source, not just one produced by combustion, so they can run on heat from solar, geothermal, biological, nuclear sources or waste heat from industrial processes.
...
Power output of a Stirling tends to be constant and to adjust it can sometimes require careful design and additional mechanisms.

 

[anorlunda]

I meant to look into the rules, but 8m going to guess they used hand and pedal power for "purity" reasons; a sailboat should be powered by wind and controlled by people, period.

No it's not propulsion. Below is a picture of a conventional sheet winch used to pull the ropes that control sail shape. It is those (plus raise/lower the hydrofoil fins) that they converted to hydraulic.

 

[russ_watters]

No it's not propulsion. Below is a picture of a conventional sheet winch used to pull the ropes that control sail shape. It is those (plus raise/lower the hydrofoil fins) that they converted to hydraulic.

View attachment 207872

I chose my words carefully: powered by wind and controlled by people. If you have a generator or large battery bank, that violates the "powered by wind" philosophy. Admittedly though, they are softening up on the "controlled by people" part a bit, at least in terms of information if not direct fly by wire.
[Edit]
I was speculating, but that is indeed the logic:
https://www.quora.com/Why-are-they-constantly-grinding-on-America’s-cup-racing-yachts

 

[russ_watters]

...Not to get too far off track, but it looked to me like the hydrofoil lift and trim was not fly by wire (I saw a lot of forward drooping), which seems a bit scary to me. I kept expecting to see one dolphin-dive and cartwheel.

 

[anorlunda]

I chose my words carefully: powered by wind and controlled by people. If you have a generator or large battery bank, that violates the "powered by wind" philosophy.

No, not if the battery is used to adjust the controls, and does not power propulsion. The phrase "wind powered" refers to propulsion. To say otherwise would make it illegal to have a spring loaded button, push/push to release. And the way those guys run on the edge, nobody could get away with "small" battery is OK, but "big" is illegal.

 

[anorlunda]

...Not to get too far off track, but it looked to me like the hydrofoil lift and trim was not fly by wire (I saw a lot of forward drooping), which seems a bit scary to me. I kept expecting to see one dolphin-dive and cartwheel.

I agree, it looks scary. And the helmsman can certainly control them incorrectly.

But I saw a close up of the steering wheel (sorry, I can't find a picture right now). It had buttons to raise/lower those fins, and if you watch the videos, you can see them going up and down when nobody is near them. They are remote controlled.

 

[russ_watters]

No, not if the battery is used to adjust the controls, and does not power propulsion. The phrase "wind powered" refers to propulsion. To say otherwise would make it illegal to have a spring loaded button, push/push to release. And the way those guys run on the edge, nobody could get away with "small" battery is OK, but "big" is illegal.

They do make compromises, but clearly this is not one of them. If electrically actuated controls were allowed, they would have stopped hand (and foot) cranking decades ago and switched to electric motorized winches and big battery packs or gas generators. They hand and foot crank because they felt a line would have been crossed otherwise.

 

[russ_watters]

I agree, it looks scary. And the helmsman can certainly control them incorrectly.

But I saw a close up of the steering wheel (sorry, I can't find a picture right now). It had buttons to raise/lower those fins, and if you watch the videos, you can see them going up and down when nobody is near them. They are remote controlled.

Yes, I know the activation is push-button, but when I say "fly by wire", I mean full fledged fly by wire, which includes computer control. I don't think there is any computer control of the wings. I think the front to back trim is by the same set of buttons on the helm.

 

[RonL]

I don't dispute what you say, but I can't help thinking of the video of this year's America's Cup Races. They replaced the old direct drive winches with hydraulics. They must have given up some efficiency. What benefit could they gain in return?

1. Energy storage: Crew members (when they get the chance) manually crank the hand wheels to store energy in the hydraulic accumulator. The energy is used later when needed. With a direct drive, power must be supplied in real time.
2. Multi-station generators. Multiple hand cranks allow multiple crew members to generate energy to be stored.
3. Centralized command and push-button application of power. The helmsman had buttons on the steering wheel that commanded sail and other boat adjustments utilizing the previously stored energy.

It is hard, but not impossible, to imagine similar benefits on a bicycle. Perhaps a multi-rider bicycle could be closer to a yacht. Instead of coasting downhill, the cyclist could store energy to help going up the next hill.

It would be a fun project to design a car for city traffic that uses a more-or-less constant power engine plus accumulator. Power generation could be levelized while the vehicle goes up/down/accelerate/decelerate. The accumulator and drive motors could be hydraulic or electric.

It would be even more fun to watch a Tour de France where the cyclists could store/release energy on command. They could use their own stored energy to put on a burst of speed to pass the pack. If that existed for all competitors, how would race tactics evolve? Of course, the accumulator+motor must not be very heavy if used in racing.

In line with what you are saying, a method to have weight transformed into forward motion is something I tried to get patent coverage in 1978 (no success)

 

[anorlunda]

In line with what you are saying, a method to have weight transformed into forward motion is something I tried to get patent coverage in 1978 (no success)

Bummer on the no success.

Sounds interesting, but you need to learn to use math to express yourself. I got these words from your drawing, "Piston in front of power position might carry a small ..." That's not the right kind of language for a patent application. You need to calculate what the piston will definitely do based on first principles.

 

[RonL]

Bummer on the no success.

Sounds interesting, but you need to learn to use math to express yourself. I got these words from your drawing, "Piston in front of power position might carry a small ..." That's not the right kind of language for a patent application. You need to calculate what the piston will definitely do based on first principles.

Kind of you to say it's interesting, it took me many years to finally realize the biggest flaw...as speed and resistance increase weight does not. also I'm not sure how reliable a wheel like that would be at high speed. The words the patent attorneys used sounded much better, but the patent office used a patent based on an air design to say I had nothing new and useful, (as I recall).
PF has taught me the value of proper words and math that are a necessity in the presentation of ideas, but I'm afraid that I'm too old to make the changes needed, The brain seems less efficient every day lately.
If the numbers I used are correct it's good up to around 10 mph on level ground, down grades or breaking allow the storage to some extent of regenerative power.
I believe hydraulic systems offer some interesting options, especially when intertwining electric and steam systems.

 

[RonL]

Instead of an electric motor, can it be substituted with an hydraulic force / power amplifying system instead?

If yes, how would it work? Could chains still be used?

Instead of an electric motor powering the hydraulic system, could the rider power the hydraulic system through force / power application whilst pedaling?

I hope my insertions of drawings and my thoughts about your question has not been interpreted as a thread hyjack in any way, I feel very strongly that the idea of weight transformed into hydraulic pressure flow has some merit. Looking forward to more interaction from others, as I feel this is a very good topic.
Thank you for asking the question.

 

[Tabaristiio]

I hope my insertions of drawings and my thoughts about your question has not been interpreted as a thread hyjack in any way, I feel very strongly that the idea of weight transformed into hydraulic pressure flow has some merit. Looking forward to more interaction from others, as I feel this is a very good topic.

That's totally fine and you're welcome!

 

[CarlM]

The weight to energy system with all the "might be's" and "could be's" is very close to a lot of perpetual motion proposals which have been brought up for the last 200 years. That is why it got rejected. There is no free lunch.

 

[RonL]

The weight to energy system with all the "might be's" and "could be's" is very close to a lot of perpetual motion proposals which have been brought up for the last 200 years. That is why it got rejected. There is no free lunch.

These are the drawings used by the patent office when they rejected my claim...

The intent of my drawings are to capture some amount of momentum energy, when slowing, braking, or a downward grade, with the use of hydraulic flow and storage.
My idea originated on a trip to Florida, observing wheels, hitting puddles of water on the highway, at speed. The thought of capturing some of that energy with a fluid in an enclosed and controlled condition, along with the knowledge that I can't lift a car but I can push it, on a few occasions using a forward push of about two or three feet, I have lifted a car up onto a six inch high slab. (momentum transformed into lift)
It is not a PM idea, but merely a method of otherwise wasted energy being captured and stored for reuse.

 

[bob012345]

There is no such thing as a "power amplifying system". That would violate conservation of energy.

There is no conservation of power law. Power can be amplified as long as energy is conserved. For example, energy fed in at a steady rate can be output in shorter bursts yielding higher power. Of course, average power is the same. Power can be amplified with time just as torque can be amplified with leverage with a wrench. Neither violate energy conservation.

 

[bob012345]

These are the drawings used by the patent office when they rejected my claim...
View attachment 208107 View attachment 208109 View attachment 208110
The intent of my drawings are to capture some amount of momentum energy, when slowing, braking, or a downward grade, with the use of hydraulic flow and storage.
My idea originated on a trip to Florida, observing wheels, hitting puddles of water on the highway, at speed. The thought of capturing some of that energy with a fluid in an enclosed and controlled condition, along with the knowledge that I can't lift a car but I can push it, on a few occasions using a forward push of about two or three feet, I have lifted a car up onto a six inch high slab. (momentum transformed into lift)
It is not a PM idea, but merely a method of otherwise wasted energy being captured and stored for reuse.

The concept is a good one, it just depends on the details. How much energy can be captured, stored and released at what cost? Regenerative braking used today in some electric cars seems fairly straightforward. Maybe your concept has a different application...Your lawyers should have helped you rewrite the application in a way the USPTO would understand but apparently they didn't do that.

 

[Tabaristiio]

I hope my insertions of drawings and my thoughts about your question has not been interpreted as a thread hyjack in any way, I feel very strongly that the idea of weight transformed into hydraulic pressure flow has some merit. Looking forward to more interaction from others, as I feel this is a very good topic.
Thank you for asking the question.

By the way, I wanted to ask what you meant by 'weight transformed into hydraulic pressure flow'?

 

[RonL]

The concept is a good one, it just depends on the details. How much energy can be captured, stored and released at what cost? Regenerative braking used today in some electric cars seems fairly straightforward. Maybe your concept has a different application...Your lawyers should have helped you rewrite the application in a way the USPTO would understand but apparently they didn't do that.

That was when I was young and living like a church mouse, they did offer to continue, but I was not sure if they were trustworthy and I just did not have the funds to go further.

 

[RonL]

By the way, I wanted to ask what you meant by 'weight transformed into hydraulic pressure flow'?

If you have ever used a hydraulic jack to lift a weight, then when you release the check valve there is a weight generated pressure flow of fluid back into the reservoir.
In the case of our discussion, momentum carries the weight of a car onto the top of the piston and then weight causes the piston to collapse in the chamber and the oil to be squeezed through the lines to the accumulator, then through a motor and back to the wheel system.

 

[anorlunda]

It is very hard to be an inventor if you can't do the calculations and check the conservation laws, and don't have support from a helper who can do it for you.

Without that, about the only way to succeed is to build a working prototype.

 

[RonL]

It is very hard to be an inventor if you can't do the calculations and check the conservation laws, and don't have support from a helper who can do it for you.

Without that, about the only way to succeed is to build a working prototype.

I agree for the most part, but being an inventor of things in ones mind is easy, transferring the ideas to others becomes the hard part if one does not have the proper education.
Before this thread goes into the almost dead zone, I do want to encourage anyone in a mechanical or electrical path to look very closely at what is possible with both hydraulic and electric working together, they are almost the same in many ways.
This might make a great senior project and in my mind has some very unique variations of what is the current norm.

 

[russ_watters]

I agree for the most part, but being an inventor of things in ones mind is easy, transferring the ideas to others becomes the hard part if one does not have the proper education.

Inventing things in your mind isn't inventing, it is imagining. Inventing means actually designing or creating the thing.

 

[RonL]

Inventing things in your mind isn't inventing, it is imagining. Inventing means actually designing or creating the thing.

I will have to respectfully disagree, the patent office has many patents, filed by inventors, which have never been built.
https://en.wikipedia.org/wiki/Invention

Invention is often a creative process. An open and curious mind allows an inventor to see beyond what is known. Seeing a new possibility, connection or relationship can spark an invention. Inventive thinking frequently involves combining concepts or elements from different realms that would not normally be put together. Sometimes inventors disregard the boundaries between distinctly separate territories or fields.[citation needed] Several concepts may be considered when thinking about invention.

Re-envision[edit]
To invent is to see anew. Inventors often envision a new idea, seeing it in their mind's eye. New ideas can arise when the conscious mind turns away from the subject or problem when the inventor's focus is on something else, or while relaxing or sleeping. A novel idea may come in a flash—a Eureka! moment. For example, after years of working to figure out the general theory of relativity, the solution came to Einstein suddenly in a dream "like a giant die making an indelible impress, a huge map of the universe outlined itself in one clear vision".[15] Inventions can also be accidental, such as in the case of polytetrafluoroethylene (Teflon).

 

[johnsherdy10]

This is great idea! But transferring the ideas to becomes real so hard.Anyone help you ?

 

[RonL]

This is great idea! But transferring the ideas to becomes real so hard.Anyone help you ?

Not sure if this is directed at Tabaristiio or me, so I'll give my short answer...this is basically the first time I have shown my drawings to anyone, as I had pretty well come to a conclusion the design would be far too complicated for a minimal return.