Since the wheels have more mass with hub motors, they do not move up and down as quickly going over bumps. More of the bumps must be absorbed by the flexing of the tires. Perhaps this is a good place for tall sidewall tires like in older days.
I still believe that the whole motor-in-wheel-hubs idea needs more discussion. For many years, car designers tried to limit the weight of car components not protected by suspension and dampers, because the constant up-and-down motion of wheels absorbs kinetic energy - hence the trend to use lightweight alloys instead of steel for wheels. Also, motors in wheel hubs are constantly exposed to vibration, dust, little rock impact, moisture, or even snow and ice (I live in Canada, eh?). And the motor cooling problems mentioned here are on top of all that.
@Kerbe #12705 I am sure there will be an extensive round of reliability testing and real-life testing, and weak spots will require redesign; I am sure that company will do whatever is best for the product If, at that point, the in-wheel motors will prove to be a solid and problem-free choice, that's fine with me. If not, then there will be choices to be made. The impact of constant long-term vibrations and mechanical jolts on electronic and electrical components is rarely positive, especially when they manufactured with fine tolerances between moving parts for efficiency.
@Jiri Dvorak Remember - all of the delicate electronic components are inside the body shell - only the motors (which are, essentially, mechanical devices) are in the wheels...
The motors are fully-encased in steel shells and, according to the manufacturer, have seals that will need to be replaced every 5-10 years to maintain weather-tightness. These are not open and exposed DC motors...
I imagine that the rear tire has to be the same diameter as the front tires otherwise it would have to rotate at a different rate. And then once up to speed wouldn't it be more efficient if the front wheels or the rear wheels just went into freewheeling ( neutral ) since the aerodynamics wouldn't need all that hp to keep things trucking along and it would give the freewheeling motors some cooling off time?
Nice but digital readout number would be easier to make sense of. Is the back tire the same diameter as the two in front? On a 3 wheeler, how do you make sure that rear tire isn't a bit out of parallel with the front wheels? If that rear is anything but perfectly straight ahead then it would be a constant steering fight.
@rahellem Another requirement: Brakes need to work when the vehicle is powered off as well. Wouldn't do to have your vehicle begin to accelerate down the hill after you switch it off!
Can someone help me understand the need for the disk brake in these motors. Surely if the electronics can traction control, vectoring, regenerative brake etc. Why are there still disk brakes? Seems the cost of those brakes, brake cylinder, booster and all that seem sup-purposeless. Some issues need to be resolved such as dissipation exec energy, energy off parking brake. Please enlighten me.
@rahellem If the battery is fully-charged the motors will not regen - because the power they generate will have nowhere to go. Regen on any EV only happens after the SOC drops to a certain point, set by the BMS. In addition, mechanical brakes are required by law: They must be included for homologation of the vehicle.
Most of you have seen the video interviews with Chris and Steve. Attached is a clip from one of those videos that shows the prototype rear hub motor with Steve doing an examination. It clearly shows two blue fittings for coolant lines, annotated in red. Don't know if that will be in final production, but the hub motors that are using all have coolant provisions.
Infinity withdrew pure steer by wire and recalled the cars and replaced it with a conventional hydraulic system after problems. Pretty sure it is not currently legal on the road anywhere.
@Bernard_S ...although many manufacturers - including Tesla - are currently working on developing it as a technology. Much in the same way that side-view cameras or steerable headlights are legal in some places but not others.
Whilst it's interesting from a technological point of view I can't help but think it's pretty pointless and potentially dangerous. But there again, I am quite old 😉
@Bernard_S Most power steering systems are electrical these days so it's not a major leap, especially with increasing autonomous capability in vehicles. And it's the older population who will benefit most: Instead of having their cars taken away from them, forcing them to rely upon relatives or sketchy community transit options they'll be able get into their own car and tell it to take them to their medical appointments, or shopping or visiting or whatever!
So you imagine that the steering box is somehow disconnected from the steering wheel you hold in your hands and a delta is applied to the inverter output to effectuate your lane change? The mind boggles . . .
@wdudan73 I imagine it's an extension of LKA, electrical power assist and throttle-by-wire: Above certain speeds, the vehicle's AI would interpret minor manual steering input as a throttle command. Or, maybe, differential steering would work only when the vehicle is driving autonomously. Or, perhaps, Aptera will have steer-by-wire, in which case there's no mechanical linkage between the steering wheel and the front wheels - Infinity has had vehicles with SbW since 2014... There are many possibilities!
I’m pretty sure the wheels turn as well as use torque vectoring. Surely, they are not relying entirely on torque vectoring at high speeds, except for very minor direction changes, like keeping you in your lane on a straightaway. Any sharper turns made solely with torque vectoring would wear your tires quickly. A combination of turned wheels and torque vectoring is best for all situations found in normal driving.
@pvsmaine Again, at high speed it's very unlikely - except in an emergency maneuver - for drivers to make MAJOR directional turns: At 70 mph, one doesn't "turn" into a lane-change so much as one "veers" into it and interstate highways are not built with sharp turns along their routes. It's the gentle moves - like lane-keeping and lane-changing where turning faired outrigger wheels would cause them to work like rudders or air-brakes, seriously impeding airflow around the vehicle and affecting both handling and efficiency. Tire wear shouldn't be an issue as a wheel isn't stopping and being dragged on the pavement, one is simply speeding up to pull harder while both are still rolling.
No, both wheels have essentially equal torque at the given vehicle speed so it takes just a slight turning of the steering wheel to redirect the car. The steering box is mechanically turning the car, not any 3-phase energy change. Also in the photo of the wheel taken from under the car you can see both coolant hoses in addition to the orange 3-phase power lines.
The prototype that Jay Leno drove has a single forward motor, ala Archimoto, which has been replaced in the new Aptera with hub motors. I've noticed that one of the new EV pickup trucks is powered by hub motors all around featuring gleaming copper windings highly visible from the outside. Not the best idea for production trucks in case someone decides it would be fun to pound a chisel into the exposed windings, ouch. Glad that Aptera has those wheel shrouds!
@wdudan73 At low speeds, yes, the wheels will turn - but, at higher speeds (when airflow comes into play) the plan is for the Aptera to "steer" by varying the power supplied to each wheel. "Torque vectoring" - as a term - is usually applied to something done in a vehicle's rear differential gearset: The actual term for what Aptera plans to do is "differential steering" - which works by (believe it or not) torque vectoring.
@Len That's how torque vectoring works: Wheel-speed is controlled individually. It's also how military tanks are steered. The point with Aptera is that, if you're travelling at speed and you turn the wheel, the wheel pants will act as rudders or sails and impede the airflow. If you increase the speed of the wheel opposite the direction you wish to turn and decrease the speed of the opposing wheel, the vehicle will turn without actually turning the wheels.
How well will the wheels be regulated to spin at the same rpm? I would think that if one front wheel is rotating faster then the vehicle would tend to steer to one side. Also the slower rotating tire would wear out sooner.
@loswa Yes, the FWD version has 100 kW - delivered by two 50 kW motors. The AWD version has 150 kW, delivered by three 50 kW motors. They've been pretty clear about this.
@loswa I believe you're showing the wrong motor description
: We've been told that it's a 50 kW motor and the photos taken when they arrived at Aptera showed them to be bright green. If you check the Elaphe website you'll see that the M700 fits that description, not the L1500 as in your image.
@Len Hi Len. I am pretty sure those are the three high voltage cables. This is a standard connection on most EV's that utilize a 3-phase, 6 pole AC motor. The cooling hoses will usually be an input and output.
Since the wheels have more mass with hub motors, they do not move up and down as quickly going over bumps. More of the bumps must be absorbed by the flexing of the tires. Perhaps this is a good place for tall sidewall tires like in older days.
I still believe that the whole motor-in-wheel-hubs idea needs more discussion. For many years, car designers tried to limit the weight of car components not protected by suspension and dampers, because the constant up-and-down motion of wheels absorbs kinetic energy - hence the trend to use lightweight alloys instead of steel for wheels. Also, motors in wheel hubs are constantly exposed to vibration, dust, little rock impact, moisture, or even snow and ice (I live in Canada, eh?). And the motor cooling problems mentioned here are on top of all that.
I imagine that the rear tire has to be the same diameter as the front tires otherwise it would have to rotate at a different rate. And then once up to speed wouldn't it be more efficient if the front wheels or the rear wheels just went into freewheeling ( neutral ) since the aerodynamics wouldn't need all that hp to keep things trucking along and it would give the freewheeling motors some cooling off time?
Nice but digital readout number would be easier to make sense of. Is the back tire the same diameter as the two in front? On a 3 wheeler, how do you make sure that rear tire isn't a bit out of parallel with the front wheels? If that rear is anything but perfectly straight ahead then it would be a constant steering fight.
It would be informative and nice to have a screen accessible that showed the rpms of each of the motors.
I read,,,
“Most regen systems will not fully bring the car to a stop – the mechanical brakes take care of the last few miles per hour.”
Can someone help me understand the need for the disk brake in these motors. Surely if the electronics can traction control, vectoring, regenerative brake etc. Why are there still disk brakes? Seems the cost of those brakes, brake cylinder, booster and all that seem sup-purposeless. Some issues need to be resolved such as dissipation exec energy, energy off parking brake. Please enlighten me.
Most of you have seen the video interviews with Chris and Steve. Attached is a clip from one of those videos that shows the prototype rear hub motor with Steve doing an examination. It clearly shows two blue fittings for coolant lines, annotated in red. Don't know if that will be in final production, but the hub motors that are using all have coolant provisions.
Infinity withdrew pure steer by wire and recalled the cars and replaced it with a conventional hydraulic system after problems. Pretty sure it is not currently legal on the road anywhere.
So you imagine that the steering box is somehow disconnected from the steering wheel you hold in your hands and a delta is applied to the inverter output to effectuate your lane change? The mind boggles . . .
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I’m pretty sure the wheels turn as well as use torque vectoring. Surely, they are not relying entirely on torque vectoring at high speeds, except for very minor direction changes, like keeping you in your lane on a straightaway. Any sharper turns made solely with torque vectoring would wear your tires quickly. A combination of turned wheels and torque vectoring is best for all situations found in normal driving.
No, both wheels have essentially equal torque at the given vehicle speed so it takes just a slight turning of the steering wheel to redirect the car. The steering box is mechanically turning the car, not any 3-phase energy change. Also in the photo of the wheel taken from under the car you can see both coolant hoses in addition to the orange 3-phase power lines.
The prototype that Jay Leno drove has a single forward motor, ala Archimoto, which has been replaced in the new Aptera with hub motors. I've noticed that one of the new EV pickup trucks is powered by hub motors all around featuring gleaming copper windings highly visible from the outside. Not the best idea for production trucks in case someone decides it would be fun to pound a chisel into the exposed windings, ouch. Glad that Aptera has those wheel shrouds!
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exactly
I would trust very well controlled considering the Aptera will have torque vectoring but ¯\_(ツ)_/¯ all new to me, in that I never had that feature
How well will the wheels be regulated to spin at the same rpm? I would think that if one front wheel is rotating faster then the vehicle would tend to steer to one side. Also the slower rotating tire would wear out sooner.
@Kerbe - Thank you for your feedback. I have found several pieces of information on this:
Maybe they will go with an S400 on the rear wheel and 2 M700 on the front for 3 wheel drive. Or Aptera will spec a custom development motor.
Aptera also mentioned that the Paradigm model has 100 kW of power.
The motors have a rotor portion and a stator portion.
https://in-wheel.com/en/videos/