What has six wheels and runs on water? Azaris — a new off-road vehicle prototype from Ferox. Azaris has a rocker suspension modeled after the one on the Mars rover. The problem is, linking four drive wheels on a rocker suspension would be a nightmare. The usual solution? Motors directly in the wheels. But Ferrox has a different approach.
The vehicle has a conventional BMW motorcycle engine but instead of driving a wheel, it drives a pump. The pump moves fluid to the wheels where something similar to a water wheel around the diameter of the wheel causes rotation. The fluid is mostly water and the pressure is lower than a conventional hydraulic system. Auto Times has a video of some stills of the prototype and you can see it below. We haven’t actually seen it in motion, unfortunately.
According to media reports, the pressure runs from 200 to 1,000 PSI which is a lot lower than in a conventional system. The motorcycle engine provides 100 horsepower and could be replaced by an electric motor if desired. They also quote the motors as being 98 percent efficient, although we think that means considering the energy in the water pump’s output to the wheel’s energy, not the thermal efficiency starting with the motor, as an internal combustion engine is doing great to accomplish 50% efficiency.
The selling point is that you can drive wheels using a liquid drivetrain that is supremely flexible. This allows you to do things like the rover-style suspension that would ordinarily require heavy motors in the wheels. The liquid motors are about 24 pounds each. Equivalent electric motors could weigh up to 66 pounds. The motorcycle engine doesn’t even max out the amount of power the wheels could deliver, so there’s room to grow.
These are prototypes and not for sale at the moment, unfortunately. They are simply to showcase Ferox technology. We couldn’t help but wonder if anyone has tried a similar scheme for a robot or other hacker drivetrain?
We’ve seen water power charging a cell phone, but that’s hardly the same thing. We also saw some pretty conventional but tiny hydraulics in this model excavator. The idea is the same though. Use hydraulics to move something with a remote motor.
https://www.youtube.com/watch?v=O9tObFUjcpQ
A video of “stills” (sigh!).
It is a lot harder to do photorealistic CGI for video… Maybe after they get some investors money (or run a crowdfunding campaign?) they will have enough money to do render a video.
Not only that, but no narration or information of any kind. Who is this supposed to impress? It just annoyed me for wasting my time.
my lawn mower has a hydrostatic transmission. well… there you go.
“The vehicle has a conventional BMW motorcycle engine but instead of driving a wheel, it drives a pump. The pump moves fluid to the wheels where something similar to a water wheel around the diameter of the wheel causes rotation. ”
Ahem. Although I’d worry about longevity and seals.
So… its not hydrostatic, and not quite hydrodynamic, but it uses non-positive displacement motors to drive the wheels? I’m seriously skeptical of the design choices here. However, looking at the pump and motor on their website, it looks like a cam actuated radial piston pump and motor, made from machined plates instead or the usual machined castings I’m used to seeing. Water wheel my ass, this is hydrostatic with fixed displacement directly proportional to engine rpm. It would increase efficiency to use variable displacement axial piston pumps or motors, which are lightweight and readily available.
‘”instead of using hydraulic fluid, the motors in the six-wheeled Azaris will be driven by 95 per cent water, with the remainder a combination of anti-corrosion, lubrication and antifreeze solution. They generally operate between 200 and 1000psi, but can push to 1500psi in high-load applications.”
https://www.caradvice.com.au/706314/ferox-azaris-inside-the-development-of-a-fluid-powered-aussie-built-concept/?source=carousel&slot=0
When I looked up “hydraulic fluid” on Wikipedia, there was a whole chapter about water based fluids, with it’s advantages (not flammable, less environmental impact in case of leakage) and drawbacks (e.g. less lubrication).
Really? A video of a vehicle that doesn’t show motion? Looks like Marketing got a little ahead of R&D…
….. It’ll be on crowd funding soon ……
I want to buy a internal combustion motor with 50% efficiency. Can you send me a data sheet and part number? I think Carnot won’t allow that. But maybe I’m wrong.
Answered my own question.
http://large.stanford.edu/courses/2011/ph240/goldenstein2/
Thanks!
Damn interesting. 60% efficiency in marine diesel engines. HCCI, didn’t know about those. The airplane engine I don’t even understand how it works. Supersonic shockwave ignition?
I can built you one – there will be a massive quote for heat exchanges, turbine blades, magnets and full spectrum solar cells. Also quite a bit lawyers are needed if science step on our way.
Does it need to move?
The unsprung weight of hub motors really, really hurt the idea.
But as the website says, the fluid motors weigh less than an equivalent electric motor.
Next time you go to a fair with the all the large show rides, have a look up at the hydraulic motor that moves those tones of steal around in the air.
You can get massive amounts of torque out of such a small motor.
I have often thought about this in the past. I even designed the concept of a continuously variable hydraulic pump on paper.
You get lower unsprung weight in several ways –
Limited slip can be done with small valves.
No requirement for differentials.
Traction control can be done across all four (or more) wheels as a single unit and the control can be sprung weight.
A regenerative breaking unit can be sprung weight.
Breaking systems can be sprung weight.
No heavy transmission axles.
No complex CVs on steering transmission.
No transmission backlash.
Instant unsprung hub locking for four wheel drive. (Simple solenoids around hypiods).
Hydraulic (swashplate and turbine) motors of all sorts are common on slow equipment (mining, logging, earthmoving etc.) because it saves a huge number of direct-drive components (could you imagine the CV joints and complexity in a huge mining truck?), but is done at the expense of efficiency. If you’re losing 20 – 50% of your horsepower to fluid flow losses (not unheard of) the hydraulic fluid heats up. It really heats up – never grab hydraulic lines on big equipment if it’s been running. Now imagine what happens when that hydraulic fluid is water….
Good call, I hadn’t thought about that. It will be effectively crippled after it warms up. I was thinking myself of the hydrostatic front axle option on john deere’s 3130 which was a disaster for safety, having no holding ability on slopes.
I know of valves with integrated control electronics, where the design temperature was 105°C oil temp. For water you probably want to stay below 100°C, because you do not want to construct a steam engine, but you do not need to stay much below. But once I saw a fan for the cooler (radiator) for the hydraulic fluid: When we cranked it to full power, you had to fear it makes a take off – more than 500W, something like 24V and similar amps
The hydraulic transmission is indeed cool but the name Azaris ? Bad choice at least for portuguese speaking folks as “AZAR” means BAD LUCK !
Chevy Nova!
And Ferrox hints at “rust” – an unfortunate choice for a vehicle, especially one dependant substantially on water.
The CEO’s surname is Wheeler …
well, Audi release e-Tron* car in french speaking country…
*e-Poop in Shakespeare language.
Repost due to my original comment appearing to be lost to the system:
Their logic is a bit baffling. In the caradvice article linked in the comments they state, “You would have a battery pack, electric motor linked into a pump, and then the pump drives the fluid transmission system, which is what’s pushing around the in-wheel motors.”
So uh… why not just put the electric motors in the wheels? Why introduce another source of loss when electric motors are already suited to drive the wheels directly? I know the answer: The often flawed desire to be “different”; regardless of logic.
They cite a goal of 98% efficiency thanks to tight tolerances, but if that was really feasible the industry would already be there today (tight tolerances are expensive and susceptible to foreign debris). Instead an individual pump or motor accomplishes about 12% efficiency and when you pair them you get a hefty 25% loss. Ouch. At the end of the day, based on what they’re describing and photos of the drives they’re still just operating a tangential piston motor; I suspect something similar to what EZ Trac is doing for hydraulically driven front axles in trucks. The only key difference is the pistons move with the hub rather than staying stationary with the spindle.
What I also don’t understand is why water and why at lower pressures? Lower pressures just means that it needs higher flows to achieve the same horsepower. The reason modern hydrostatic transmissions run in excess of 5000 psi is because it lets them get away with lower flow. That means smaller components and smaller hoses. You do increase loss from leak-by, but you either get loss from leak-by or you get loss from pressure drop due to high flow rates. Pick your poison.
It gets better though, for regeneration they want to use accumulators. Since they’re using a low pressure system that means BIG accumulators. Once again, lower pressures aren’t always better… I just don’t see why they think this is the way to go. Or necessary.
I don’t know about electrics, but the hydro, like steam, can produce peak torque at zero RPM, which maybe is a big enough advantage in an ATV to make it worthwhile.
Electric motors generally have the same ability; producing maximum torque at 0 or very near 0 rpm.
Strong motors are heavy. Maybe they concluded that hydro motors are less heavy meaning less unsprung weight. Don’t know …
They are, but hydraulics aren’t exactly light either. Honestly wheel motors are a neat idea in terms of packaging and simplicity, but in terms of suspension dynamics it’s a terrible idea.
If they could do it with actual hydraulic oil they would have a start on an electric tractor
2007 called, it’s glad you’ve caught up…
https://thekneeslider.com/hydrostatic-drive-diesel-motorcycle/
https://www.pirate4x4.com/forum/general-4×4-discussion/763311-hydrodynamic-buggy.html#/topics/763311
And Hydrostatic, hydrodynamic, and awd motorcycle all turn up some similar hillbilly creations on YouTube.
“Internal composition engine” is, as often, proof of …
Well, the ones without internal “composition” are harder to tune-up!
So all we know is that an an odd looking car might exist. They don’t make a compelling case for any of its design features.
Are you new here?
Oh, are we doing this thing again where industrial designers create high quality artwork of an idea, and know just enough engineering to make it sound like the concept has a basis in reality?
A more serious question is what are the losses incurred by a belt drive vs chain vs bevel gear? I can’t seem to find any info with actual numbers.
The reason for this question is that it seems that moving the drive motor to the pivot of the swing arm seems like an obvious war to reduce the un-sprung mass. But that seems so obvious someone must have already evaluated this idea and determined that direct drive is worth the un-sprung mass penalty.
/suddenly wants to see someone try to make a 3d printer with water-powered motors.
“internal composition engine”
A what?
“linking four drive wheels on a rocker suspension would be a nightmare.” – except that Scammel solved it about 50 years ago on their very well regarded trucks:
https://i1.wp.com/racem.org/wp-content/uploads/parser/Scammell-explorer-1.jpg
Also hydrostatic drive is massively lossy and heavy and unsuited to most vehicles outside of heavy plant where weight doesn’t matter or is considered a bonus (ballast).
I want!
If you want something to look real it can’t be perfect with perfect lighting and perfect curves it needs to look a bit shit. Now as for the tech being proposed well every piece of heavy construction equipment uses hydraulic moton systems so this really is nothing special and in fact, water is a terrible choice because it will heat up this is why you don’t use it for brake fluid.
To be able to drive off the pavement, off-road vehicles need several characteristics: They need to have a low ground pressure, so as not to sink into soft ground, they need lot of ground clearance to not get stuck on obstacles, and they need to keep their wheels or tracks on the ground so as not to lose traction.