Tesla mentions that the mechanical components of the traditional wiper blade create a lot of friction, which requires more power to the motor that moves the arm back and forth.
I thought it was the friction of the wipers themselves on the glass that takes the most power...
In any case, some research reveals that typical wiper motors are <50W, which even if that was reduced to 0, would be an insignificant fraction of the total power draw of an EV, the motor powering the car being capable of over 200kW (200000W). I doubt this is going to have much of an effect on the overall range.
> That looks like a linear motor, which unless I'm missing something is spectacularly power hungry.
They are, by themselves, not more power hungry than the corresponding type of rotary motors.
Their biggest problem regarding power usage is that they can't use gears to gain mechanical advantage. Since electric motor losses are roughly proportional to their torque (or force, in case of linear motor), it is often the case that the linear motor will require more power.
But a quick look at some of the windshield wipers mechanisms shows that rotary motors that drive them are in a mechanically pretty disadvantageous position, with a very short lever arm compared to what a linear motor would be. So it might work well in this case.
This article is full of breathless praise for an idea it's just seen sketched on paper. Calling it "like a maglev", oh except there is no levitation involved.
Saying this will give increased reliability, claiming stuff like "time and weather can lead to corrosion, making the traditional setup less effective over time" which is clearly nonsensical.
I've driven cars that are 30 years old with original wiper motor assemblies still in place. This is not uncommon. There is effectively zero room to improve reliability.
If they want to have one single blade move back and forth, that's cool, but this seems like a bafflingly complex way to do it. What's wrong with a normal linear actuator? It's powered by a regular electric motor (something right in Tesla's wheelhouse), can be built very reliable, and is plenty efficient. There's no reason to build the Space Shuttle when people just want an electric car, and won't be able to tell the difference under the hood anyway. Maybe they want as many solid state components as possible for durability? Talk about diminishing returns...
No, my guess is that this is to lock down the patent so they own it (and as many other even vaguely plausible concepts as possible) and can wield it in patent battles with other automakers. More charitably, you could look at it as clearing as much land as possible so that 10 years down the line their engineers are minimally encumbered by patent concerns and can build whatever they want. Typical corporate R&D, and not particularly deserving of a Car and Driver fluff piece.
Tesla is one of the most open companies with their patents [1]. I don’t share your scepticism. I would think this is protection against someone else patenting the idea and inhibiting their ability to innovate.
OT: have you ever noticed that most scifi movies depict futuristic cars that can hover or fly but which still use traditional windscreen wipers. You'd have thought they'd add a force field that repels rain or a special coating but no, traditional wipers. Even Bladerunner 2048 did this.
I always think it's a bit incongruous to see them on the cockpit windows of airliners. Sort of like having a vacuum tube power supply for your computer.
(Two other solutions exist. One is spinning the window, you'll see it on ships. The other is making the window hot.)
I'm going to guess its because they're giving us what we expect, and can make sense of. Most spaceships have big hot engines of the type you'd probably unlikely to see on an actual spaceship, but we've been conditioned to expect big engines, so that's what we get.
Also there isn't really time in a film to explain away not needing wipers, so rather than risk having audiences thinking theres bad special effects because the rain that's falling isnt also falling on the windscreen, they just put wipers on and be done with it.
It could also be that that futuristic car you saw flying in, and can still see partially in shot is just a bog standard car that they've dressed to look like a flying car.
Traditional wipers show up even in shallow-focus closeups of people in the car, and they're immediately recognizable without explanation. It's like the ridiculously big UI elements in movie computer interfaces: for the benefit of the viewers, not the characters.
"...is supposed to be more efficient and better-looking..." Not sure how it can be better looking—all luxury cars already hide their wipers below the hood line already. Seems overly complex with many more failure points. Wipers are the one thing you don't want to fail when you need them.
Yes I had such a MB wiper and never had any trouble with it. It provided good coverage of the windshield.
Today, my MB uses two wipers, but it is nevertheless an interesting design as well. Windshield cleaner fluid is not sprayed out though jets that roughly cover the windshield; instead the cleaner fluid comes out from the blades themselves as they move across the windshield. This is almost not visible while it is happening, while cleaning the windshield just as well or better without vision obscuring spraying.
I've had a couple of those, never had one fail. Important to keep them lubed up though, and not to run them on dry windows, but that goes for all wipers alike.
My family were a Citroen (hydropneumatic suspension ftw) family growing up, so we had a variety of 'monobladed' cars, the wipers weren't one of the unreliable parts.
Can't think of anything more wasteful than using 50 Neodymium magnets to do a job that could be done with two or three "standard" magnets or, Samarium Cobalt if absolutely necessary. It's grotesque, really, if you start thinking about natural resource utilization. Imagine a hundred million cars adopting something like this. Crazy, if you ask me. A conventional rotary motor has two or three magnets and they don't even have to be high grade.
For some reason I've had a feeling for a while that designers are abusing magnets. It seems they are being thrown into everything and for the most frivolous of reasons sometimes. Isn't this a finite resource?
Is like to see how this wears in practice. Guide rails in a road setting seem like they will get gummed up fairly quickly and degrade performance unless the entire system is somehow sealed.
It’s great to see a push for innovation beyond powertrain and head unit, though.
First thing I thought of. Sliding tracks in a dirty environment are usually a headache, because of the big exposed bearing surface. There are solutions, involving bellows, seals, and such, but they're kind of overkill for a windshield wiper. Rotational bearings can easily be fully enclosed and lubricated.
Linear motors have been around for many decades, but are still a niche product.
The first commercial linear motor application was as banal as a windshield wiper. It was the 1962 "Electrac by Kirsch®"[1], a linear motor for draw drapes. Back then, large commercial buildings like air terminals were first getting big curved glass areas, and people expected them to have drapes. The string and pulley systems were not good with curves. So Kirsch came out with a linear motor unit that traveled along the drape track and pulled the drape. Multiple motors could run on the same track, for very wide drapes, so it scaled up well. Worked fine, cost too much, had 120VAC in the track.
I once expected linear motors to be a big thing in robotics, but that didn't happen.
Some here say 50W is insignificant, but this is what going above 80% means, when you improve everything to get every possible advantage. The car biz is probably very cut throat if you fall behind in mileage. Oh, there is also weight savings without motors and with single blades.
Why replace a simple but essential thing that works (i.e. current wipers) with a more complicated one that it will have lots of additional ways to fail?
> Why replace a simple but essential thing that works (i.e. current wipers) with a more complicated one that it will have lots of additional ways to fail?
Speaking of... on the model 3 rather than using standard rain sensors for the automatic wipers they got cute and used the autopilot camera and it’s fucking awful. I constantly have to screw with the wiper settings when it’s raining (which are on the touch screen because of course they are) because the auto setting is so bad. I love the car overall but this design decision was a mistake.
I hope this model of wipers get progressively improved and widely adopted. One of the issues with "semicircular" wiping is the areas which cannot be cleaned. If this works well, it will be a significant improvement in driving in rainy parts of the world.
This may be a stupid question but, is there a reason cars don't just have a single blade that goes straight across, rather than wiping in this arc motion? It seems like it'd do a much better job of wiping and avoiding streaks if it just went straight across.
The windscreen wiper is very likely to be outsourced to a 3rd party company, and they can reduce costs by having a repeatable design. In terms of a blade going on a straight line, it’s much easier to rotate a wiper blade from a motor than translate that into a linear movement.
1) having a single attaching point for the wipers makes designing stuff around it more simple
2) accurate curved tracks that match windscreens are hard to manufacture, secure and keep in shape
3) Keeping constant force for all parts of the windscreen is much harder with a track (high and low spots, change the window screen, the track needs adjusting too)
4) standard bearings are much more simple to seal
5) linear bearing as a pain to seal
6) tracks are much harder to seal against the weather
> is there a reason cars don't just have a single blade that goes straight across
Some vehicles have pantograph wipers which work horizontally, however that's a more complex design than the usual simple pivot, and you can't "park" the wipers out of view when they're not in use so they're more obstructive. They're sometimes used on car rear windows but mostly seen on commercial vehicle windshields.
Some cars (mostly benzes) also have eccentric arc systems where the wiper arm extends and retracts to cover more windshield with a single pivot.
I would guess you will need a long groove and a wheel that slides on it, and it will be prone to breaking if you consider how fast the thing should slide when its heavy rain.
Presumably, it's down to simplicity of implementation: A single servo motor that directly rotates an attached blade vs. a necessarily, due to the curvature of the windshield, curved linear rail (which ought to be more difficult to seal against debris).
There's a good movie called, "Flash of Genius" about the inventor of the intermittent windshield wiper and his efforts to defend himself against the theft of his idea.
One of the nice properties of the dual-blade setup is that if the one in front of the driver fails during a hard rain, it's possible to lean over and drive looking through the passenger-side of the front window -- at least until you can safely exit a freeway and find a safe place to stop.
Maybe less critical if the car is actually self-driving, so I guess I'm not surprised folks are thinking about this.
More critical in the case of Tesla, where there are cameras mounted behind the windshield (on the rear-view mirror). This is one of the typical talking points in the LIDAR vs optical debate, because the rain makes it difficult to see with passive optical sensors.
Have there been any developments on glass technology than can repel water? I use a anti-rain coating (a la Rain-X) which works pretty well, but you need to be above 80km/h for it to work effectively.
Silicon blades are awesome, you need to be diligent about cleaning the windshield but the blade material is more of a game changer than the motor or wiper orientation to me.
[+] [-] userbinator|6 years ago|reply
I thought it was the friction of the wipers themselves on the glass that takes the most power...
In any case, some research reveals that typical wiper motors are <50W, which even if that was reduced to 0, would be an insignificant fraction of the total power draw of an EV, the motor powering the car being capable of over 200kW (200000W). I doubt this is going to have much of an effect on the overall range.
[+] [-] KaiserPro|6 years ago|reply
By the looks of it, it also need linear bearings, which are difficult to seal against leaves, dirt, moss, ice and snow.
I'm going to wager £20 and say its not a game changer.
[+] [-] balfirevic|6 years ago|reply
They are, by themselves, not more power hungry than the corresponding type of rotary motors.
Their biggest problem regarding power usage is that they can't use gears to gain mechanical advantage. Since electric motor losses are roughly proportional to their torque (or force, in case of linear motor), it is often the case that the linear motor will require more power.
But a quick look at some of the windshield wipers mechanisms shows that rotary motors that drive them are in a mechanically pretty disadvantageous position, with a very short lever arm compared to what a linear motor would be. So it might work well in this case.
[+] [-] semi-extrinsic|6 years ago|reply
Saying this will give increased reliability, claiming stuff like "time and weather can lead to corrosion, making the traditional setup less effective over time" which is clearly nonsensical.
I've driven cars that are 30 years old with original wiper motor assemblies still in place. This is not uncommon. There is effectively zero room to improve reliability.
[+] [-] badfutureahead|6 years ago|reply
Still waiting on that.
https://www.nytimes.com/1988/09/10/business/patents-ultrason...
https://www.autoblog.com/2013/12/17/mclaren-ultrasonic-winds...
[+] [-] HNLurker2|6 years ago|reply
[+] [-] brianpgordon|6 years ago|reply
No, my guess is that this is to lock down the patent so they own it (and as many other even vaguely plausible concepts as possible) and can wield it in patent battles with other automakers. More charitably, you could look at it as clearing as much land as possible so that 10 years down the line their engineers are minimally encumbered by patent concerns and can build whatever they want. Typical corporate R&D, and not particularly deserving of a Car and Driver fluff piece.
[+] [-] deanclatworthy|6 years ago|reply
[1] https://www.tesla.com/blog/all-our-patent-are-belong-you
[+] [-] Scoundreller|6 years ago|reply
Some Mercedes models do this. The wiper shifts inward toward the middle of the stroke.
[+] [-] taneq|6 years ago|reply
[+] [-] powfeu|6 years ago|reply
[+] [-] WalterBright|6 years ago|reply
(Two other solutions exist. One is spinning the window, you'll see it on ships. The other is making the window hot.)
[+] [-] benj111|6 years ago|reply
Also there isn't really time in a film to explain away not needing wipers, so rather than risk having audiences thinking theres bad special effects because the rain that's falling isnt also falling on the windscreen, they just put wipers on and be done with it.
It could also be that that futuristic car you saw flying in, and can still see partially in shot is just a bog standard car that they've dressed to look like a flying car.
[+] [-] mrob|6 years ago|reply
[+] [-] Jonnax|6 years ago|reply
So I'm presuming it's not been seen or tested in the wild.
Seems a bit hyperbolic to call it a game changer at this point.
[+] [-] addisonl|6 years ago|reply
[+] [-] hammock|6 years ago|reply
I wouldn't dare correct you as I have no data, but I suspect many people would put brakes or a seatbelt ahead of wipers
[+] [-] tedunangst|6 years ago|reply
https://en.m.wikipedia.org/wiki/Tesla_Roadster_(2020)#/media...
[+] [-] MegaButts|6 years ago|reply
https://99percentinvisible.org/article/behind-screens-windsh...
[+] [-] todd8|6 years ago|reply
Today, my MB uses two wipers, but it is nevertheless an interesting design as well. Windshield cleaner fluid is not sprayed out though jets that roughly cover the windshield; instead the cleaner fluid comes out from the blades themselves as they move across the windshield. This is almost not visible while it is happening, while cleaning the windshield just as well or better without vision obscuring spraying.
[+] [-] jacquesm|6 years ago|reply
[+] [-] benj111|6 years ago|reply
My family were a Citroen (hydropneumatic suspension ftw) family growing up, so we had a variety of 'monobladed' cars, the wipers weren't one of the unreliable parts.
[+] [-] robomartin|6 years ago|reply
For some reason I've had a feeling for a while that designers are abusing magnets. It seems they are being thrown into everything and for the most frivolous of reasons sometimes. Isn't this a finite resource?
[+] [-] userbinator|6 years ago|reply
[+] [-] mdorazio|6 years ago|reply
It’s great to see a push for innovation beyond powertrain and head unit, though.
[+] [-] Animats|6 years ago|reply
Linear motors have been around for many decades, but are still a niche product. The first commercial linear motor application was as banal as a windshield wiper. It was the 1962 "Electrac by Kirsch®"[1], a linear motor for draw drapes. Back then, large commercial buildings like air terminals were first getting big curved glass areas, and people expected them to have drapes. The string and pulley systems were not good with curves. So Kirsch came out with a linear motor unit that traveled along the drape track and pulled the drape. Multiple motors could run on the same track, for very wide drapes, so it scaled up well. Worked fine, cost too much, had 120VAC in the track.
I once expected linear motors to be a big thing in robotics, but that didn't happen.
[1] https://books.google.com/books?id=bdgDAAAAMBAJ&pg=RA1-PA164&...
[+] [-] edf13|6 years ago|reply
[+] [-] m3kw9|6 years ago|reply
[+] [-] paganel|6 years ago|reply
[+] [-] nordsieck|6 years ago|reply
Do you mean like door handles?
Presumably because it looks cool.
[+] [-] adamkittelson|6 years ago|reply
[+] [-] koala_man|6 years ago|reply
[+] [-] NullPrefix|6 years ago|reply
[+] [-] sn41|6 years ago|reply
[+] [-] darawk|6 years ago|reply
[+] [-] edh649|6 years ago|reply
The windscreen wiper is very likely to be outsourced to a 3rd party company, and they can reduce costs by having a repeatable design. In terms of a blade going on a straight line, it’s much easier to rotate a wiper blade from a motor than translate that into a linear movement.
It’s worth nothing that other systems exist (https://www.a1-windscreens.co.uk/news/windscreen-wiper-movem...), but much less common.
[+] [-] KaiserPro|6 years ago|reply
1) having a single attaching point for the wipers makes designing stuff around it more simple
2) accurate curved tracks that match windscreens are hard to manufacture, secure and keep in shape
3) Keeping constant force for all parts of the windscreen is much harder with a track (high and low spots, change the window screen, the track needs adjusting too)
4) standard bearings are much more simple to seal
5) linear bearing as a pain to seal
6) tracks are much harder to seal against the weather
7) tracks need more lubrication
[+] [-] masklinn|6 years ago|reply
Some vehicles have pantograph wipers which work horizontally, however that's a more complex design than the usual simple pivot, and you can't "park" the wipers out of view when they're not in use so they're more obstructive. They're sometimes used on car rear windows but mostly seen on commercial vehicle windshields.
Some cars (mostly benzes) also have eccentric arc systems where the wiper arm extends and retracts to cover more windshield with a single pivot.
[+] [-] usaphp|6 years ago|reply
[+] [-] clamprecht|6 years ago|reply
[+] [-] doersino|6 years ago|reply
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[+] [-] varjag|6 years ago|reply
[+] [-] blackflame7000|6 years ago|reply
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[+] [-] cbhl|6 years ago|reply
One of the nice properties of the dual-blade setup is that if the one in front of the driver fails during a hard rain, it's possible to lean over and drive looking through the passenger-side of the front window -- at least until you can safely exit a freeway and find a safe place to stop.
Maybe less critical if the car is actually self-driving, so I guess I'm not surprised folks are thinking about this.
[+] [-] brianpgordon|6 years ago|reply
[+] [-] fyfy18|6 years ago|reply
[+] [-] xfitm3|6 years ago|reply