"...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.
Wipers are important, and underrated. Seatbelts are mostly muscle memory if not absolutely required, and you have to use the brakes basically to even start the car or get anywhere. But wipers you don't use on every trip.
One time I was taking a winter defensive driving course, and was the first person in the car to go. It wasn't my car, so it was unfamiliar. They had a number of skid pads, cones, etc. They were also pouring out water to make sheets of ice to help teach skid control.
Some of the water hadn't frozen yet, and the instructor told me to go through it. It put a full sheet of water on the windshield and I was fumbling looking for the wipers, because they weren't on the stick (it was a pull button for some reason). Of course, everyone else knew how to use the wipers by their turn. I didn't lose control of the car, and kept my cool, but it made me realize, ALWAYS check where the wipers are when driving an unfamiliar car. Even if it's not raining, if something gets on your windshield (mud, bugs, dirt), you need to know how to clean it, and fast.
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.
> Tesla was also thinking about its Autopilot system when conceptualizing the patent for the wiper system. The argument is that traditional wiper systems aren't as robust as this new electromagnetic system; time and weather can lead to corrosion, making the traditional setup less effective over time. The resulting lack of visibility could hamper Autopilot and other autonomous-driving aids that use cameras to track lanes and objects around the car. Better visibility is better for the cameras and, of course, for the driver.
That makes no sense. Autopilot cameras are not in the passenger compartment and would be unaffected by wipers.
This whole article makes no sense. They really think a small improvement in windshield wiper efficiency is going to noticeably change the range of a Tesla vehicle?
Actually the front facing cameras are housed in the assembly behind the rear view mirror (behind the windshield) and are reliant on the wipers to clear the windshield. See the following image: https://images.app.goo.gl/WWXn1PbTaE3XWQmq7
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.
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.
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.
I actually don't think they're outsourced and they're typically designed in-house. I remember the reason being the windshield wipers are almost always engineered last after almost everything else in the engine compartment. So the wiper engineers are typically given very oddly shaped small spaces that they have to fit the wiper system into, and those differ between cars so it can't just be generically outsourced.
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).
> 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.
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
This is ok but I wish one of the weird cartech projects Elon would take on is creating a transparent A pillars in cars. Maybe using driver eye tracking and exterior cameras.
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.
The Mercedes wiper didn't simply sweep out a circular arc, like most monobladed cars (including IIRC Citroëns); it used a complex gearing system to vary the blade radius to better cover the windshield's corners. Naturally, this over-engineered system was prone to breakage.
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.
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.
> 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.
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.
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.
Tesla's speaker system is 200/560W. So it's possible to get to 50W just from screen and speaker savings. And that's assuming constant worse case use of the wipers: high speed and full load like you're driving through a waterfall. Pulling up a spec sheet for a wiper motor, it looks like normal load is only supposed to draw ~6-10W.
This sort of thing is why I refer to "the noise floor" in these sorts of discussions. It's not that it's untrue that it may save a mile of range, it's just so dominated by other factors that it doesn't matter. Your human cognitive spotlight is focusing on this one fact, and it may be "true", but that doesn't make it important. It's not worth engineering effort to save amounts of power that will be casually wiped away by any number of little things.
(Sometimes you can bind together several little things into one big one worth doing, but human intuition is still often broken by the factors of magnitude involved. 6 %.0002 things still don't add up to anything significant, for insurance, even if it may feel like six things ought to matter.)
On the other hand even a 1 mile (probably less) saving over a 5 hour (~200-250mi) trip through the rain might as well be a rounding error regardless of the fuel used. Many other methods for achieving the same saving are not as flashy though.
I imagine the most important way is to ensure optimal tire pressure at all times. Many people tend to ignore this even when having pressure sensors at hand which leads to a whole lot of wasted fuel.
The reason wipers only received minor optimizations over the decades is because they work well, are cheap and enviably reliable. So any new wiper system design has a high bar to pass, beyond using new tech.
While I agree with you and am excited for whatever improvements can be made, I think the most likely retort to this argument is "While you're worrying about 10 0.5% savings, your competitor is focusing on optimizing things that actually matter."
What’s funny is all of these trade offs have always applied to ICE cars as well, but for some reason no one cares. Blasting your radio shortens your range even in a gas vehicle. Running your wipers shortens your range even in a gas car.
Additional power draw on the accessory circuit places increased load on the alternator which in turn causes the engine to run a little harder than it otherwise would. Thus burning a little extra fuel.
They produce based on current draw, but have a maximum output, usually around 60-85a for and older car, to 120-240a at 14.4vdc for a newer car or truck. There is no permanant magnet, so the coils require power to generate power. Its quite interesting.
Further to this the 12V battery effectively acts as a big capacitor while the car is running, to smooth out the power that is available.
I found this out the hard way a couple of years ago. My 12V was dead, yet I managed to jump start the car and get it running. I thought it would be ok to drive to get a new battery, as long as I kept the engine running high enough. After a couple of km the dashboard lights started to dim, so I tried reving it as high as I could, but the battery wasn't able to buffer the power and supply the ignition system, so the engine stopped. It was rush hour and I was in the middle lane, so it wasn't a particularly fun wait for the tow truck.
In the old days of lower power alternators (or really old days of generators), and lower power engines, the revs would drop noticeably, and the note change, when you turned dip lights on, aircon or even occasionally - in smaller cars - the heated rear demister! Made it very obvious the engine was working harder.
Now that tickover and fuel injection is computer controlled or we have EVs, and there's a far heavier electrical load in all cars all the time, you never notice any more. They all take power, and decrease fuel efficiency.
The range of an ICE car is not as big of a concern as with EVs, giving that they already have a substantial range, "recharging" is quick, and fuels are very energy-dense.
Silicone wipers naturally leave behind a thin silicone film on the glass. Once this film is in place, the water serves as a pretty decent lubricant so long as it's raining.
i wonder how high pressure air nozzles would fare in this application. have a small reservoir of water dispersant that get nebulised from the nozzle themselves every box and then and just push water around with the nozzles at low speed
Much more significant to me is the clear vision it affords when you come up behind a large truck/semi in wet weather. Makes passing at least possible, as opposed to being stuck, unable to pass, in a cloud of dirty water for long stretches of time.
I think it's fairly obviously mainly a marketing move. These wipers (judging by the drawings) look cool and futuristic. If they ever implement them I'm sure that's going to be the main motivation.
I can be very critical of Tesla but if there's one thing they achieved it's making electric vehicles that look cool. I don't think many teenagers saw a Prius as an aspirational vehicle but I'm pretty sure you could find Tesla posters in many a bedroom.
The only possible thing I see of practical value in this solution is that it might (might, not sure I understood well) reduce the amount of moving parts and gears. Essentially the entire motion would be controller electronically, no gears or motors.
Given the current reliability of classic wiper systems I don't think this is the improvement. Part of the reasons classic wipers have multiple moving parts (basically motor + rack and pinion) is that you want to guarantee they stay in sync and never overlap. You can put 2 simple motors on them for similar effect like the Tesla design. Tesla's solution focuses on design rather than better technical specs.
The claim that "the electromagnetic moving block induces minimal friction" says very little considering you achieve the exact same effect with a classic wiper arm mounted on a single electric motor. You probably want more than one arm anyway.
> I think it's fairly obviously mainly a marketing move.
I wonder though if it's the right marketing move and the right deployment of resources.
Car manufacturers found out a long time ago that car sales are not driven by these types of improvements. Cars are purchased emotionally and to a lesser extent functionally. Obviously a Tesla is an emotional purchase since it doesn't really make sense for most buyers to burden themselves with the higher price and inconvenience of an electric car. This seems a great deal like a little icing on the cake of 'we are just a better purchase down to this type of detail'. That's separate from the GP assertion that there is little power savings.
Sure it gets employees thinking of power savings (similar to when Apollo was done everything mattered down to the last detail). But the development and implementation of this is not trivial and it will take meetings and decisions and testing. What else could be done with those resources?
The sum of many details that stir emotion is a whole that is emotionally compelling. If cars (or any consumer product) are purchased emotionally, and this feature is perceived as cool and futuristic, surely this will incrementally add to unit sales.
See also the Model 3's AC vents. Whatever their utility & whether its better than traditional ones, they are cool and futuristic and do their part to help the car stand out from the pack. Start adding all these up and you have something.
Car companies outsourced all these types of parts years ago, which severely limit their ability to pursue these types of innovations. That made economic sense when they were competing against organizations with similar cost-cutting strategies, and are a product of the era in which those choices were made and the business climate that encouraged those choices, but it leaves them at a disadvantage when a company takes a very different, tech-driven, vertically integrated approach to product.
The maximum power of the car is not relevant to range. A Tesla uses between 200 and 300 Watt-hours per mile if I recall correctly. A Watt-hour (Whr) is a one watt load used for an hour. If it takes you 5 hours to deplete your battery, a 50W load for 5 hours will use 250 Whr. You will lose 1 mile of range because of it.
When doing motor control work and dyno testing, one of the challenges is measurement of mechanical power (and even electrical) because you need to measure up to -200kW but you care about differences of 10s of Watts.
Definitely. In my opinion, it is a marketing strategic movement to show the innovation levels of Tesla company, but for sure, this new system is not going to change the world as we know.
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.
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.
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.
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.)
> Two other solutions exist. One is spinning the window, you'll see it on ships. The other is making the window hot.
There are two more solutions I can think of: hydrophobic coatings, and blasted air. I believe these both perform quiet well in less intense rain. Unfortunately both of these suffer from performance degredation from dirt/bug/bird poo etc, so not a perfect replacement to a traditional wiper.
Many airliners already use heated window panes for de-icing. Heated windows don't work all that great in a downpour, and wiping is a simple and faster acting alternative.
Blasted air is used minimally for windscreens, but it's a common plane de-icing method for the rest of the vehicle.
The complexity and weight of using spinning windows on planes makes that idea a non-starter.
hydrophobic coatings are also in use, but are generally avoided for the duty of primary windscreens due to most hydrophobic coatings lacking durability to physical stress and contact.
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.
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.
Tesla's way of opening up patents is interesting. Hopefully someone more knowledgeable on the topic can chime in, but my understanding is that Tesla's just saying they won't initiate a lawsuit if they believe you're using their patent in "good faith". Tesla's lawyer's clarification made their "good faith" restriction much more restrictive:
A party is “acting in good faith” for so long as such party and its related or affiliated companies have not:
- asserted, helped others assert, or had a financial stake in any assertion of
(i) any patent or other intellectual property right against Tesla or
(ii) any patent right against a third party for its use of technologies
relating to electric vehicles or related equipment;
- challenged, helped others challenge,
or had a financial stake in any challenge to any Tesla patent; or
- marketed or sold any knock-off product (e.g., a product created by imitating
or copying the design or appearance of a Tesla product or which suggests an
association with or endorsement by Tesla)
or provided any material assistance to another party doing so.
So it makes sense that no one major would take up Tesla's offer, because they're not going to waive the right to sue Tesla.
That's a little bit different than, say, Toyota, which offered to licenses out their patents royalty free with no strings attached and even offer consulting on how to use them for a fee. There's some guarantees there (or can be negotiated) that the tech/goodwill won't disappear on a whim.
Those restrictions sound pretty reasonable - you wave the right to sue them for patents only. Would be kind of odd to use one of their patents freely while suing the opposite way.
Toyota announced the patent release five years after Tesla, and its mostly for technology released in 1997 for the Prius, hardly anything revolutionary now. By the way if you manage to find their contact form re. this, it says "We have closed accepting inquiries for technical support."
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?
It has a much larger area exposed to the elements (the magnetic rails). Basically this is building a mini maglev train and attaching a wiper to it, while the traditional setup is just a motor. Up to you to decide if a train is more complicated/reliable/efficient than a motor.
> 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?
On the doorhandles I can see the point: to make the vehicle more aerodynamic. Every little bit counts, four doorhandles are quite a bit of disturbance of the airflow.
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.
which are on the touch screen because of course they are
I've never driven one, but a bit of research indicates that it has a right control stalk but Tesla didn't make it control the wipers. Instead, the button on the left stalk will wipe once. The fact that videos like this exist shows just how horrible the UI is:
I'm surprised Tesla could do this, because there are laws that dictate things like what the steering wheel should do, and the order of the pedals and transmission shift pattern (perhaps not so applicable to an EV.)
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.
The area in front of my rear view mirror is the only area on my windshield wiped by both wipers presumably because all the sensors are there and they wanted some sort of redundancy.
Seems like something a Californian would invent. Looks like it would fair poorly if wiper-well fills up with snow. Can it be left lifted clear of the windshield before a hard ice?
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.
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.
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?
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[ 4.3 ms ] story [ 230 ms ] threadI wouldn't dare correct you as I have no data, but I suspect many people would put brakes or a seatbelt ahead of wipers
Brake and seatbelts typically display warning signs before failure (but not always of course).
One time I was taking a winter defensive driving course, and was the first person in the car to go. It wasn't my car, so it was unfamiliar. They had a number of skid pads, cones, etc. They were also pouring out water to make sheets of ice to help teach skid control.
Some of the water hadn't frozen yet, and the instructor told me to go through it. It put a full sheet of water on the windshield and I was fumbling looking for the wipers, because they weren't on the stick (it was a pull button for some reason). Of course, everyone else knew how to use the wipers by their turn. I didn't lose control of the car, and kept my cool, but it made me realize, ALWAYS check where the wipers are when driving an unfamiliar car. Even if it's not raining, if something gets on your windshield (mud, bugs, dirt), you need to know how to clean it, and fast.
https://en.m.wikipedia.org/wiki/Tesla_Roadster_(2020)#/media...
It’s great to see a push for innovation beyond powertrain and head unit, though.
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&...
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.
That makes no sense. Autopilot cameras are not in the passenger compartment and would be unaffected by wipers.
Source: I own a Model 3 and just looked. There is a camera on the front of the center rearview mirror on the windshield side.
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.
Here's a Hyundai engineer talking about wipers: https://www.digitalengineering247.com/article/the-back-and-f...
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.
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
https://99percentinvisible.org/article/behind-screens-windsh...
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.
* Photos and diagrams here: http://www.spannerhead.com/2012/11/28/technical-curiosities-...
* A slow-motion video of the wiper in action here: https://www.youtube.com/watch?v=KHtEAMwcWI4
* And a couple visualizations of how it works mechanically: https://www.youtube.com/watch?v=_quBiMLqNoc, https://www.youtube.com/watch?v=LdNu113Ep2U
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.
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.
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.
Certainly it will work for this case but ...
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.
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.
I see what you did there.
50W for 5 hours is 250Wh, which is a mile extra range. That’s worth having.
(Sometimes you can bind together several little things into one big one worth doing, but human intuition is still often broken by the factors of magnitude involved. 6 %.0002 things still don't add up to anything significant, for insurance, even if it may feel like six things ought to matter.)
I imagine the most important way is to ensure optimal tire pressure at all times. Many people tend to ignore this even when having pressure sensors at hand which leads to a whole lot of wasted fuel.
The reason wipers only received minor optimizations over the decades is because they work well, are cheap and enviably reliable. So any new wiper system design has a high bar to pass, beyond using new tech.
That represents about 0.5% of a Tesla's advertised range.
* Only when it rains. (It's worthless the rest of the time)
* Only if all of the motor power is saved. (Presumably the new mechanism uses some power)
* Only if the motor is running at full power the entire time it rains (even on "high" this is not true).
* Only if range is not otherwise impacted by the rain (nope).
If it rains all the time, and the above are all true-- yes, it's worth 0.5%.
Are HN posters really this dumb?
... is what i would have said.
I found this out the hard way a couple of years ago. My 12V was dead, yet I managed to jump start the car and get it running. I thought it would be ok to drive to get a new battery, as long as I kept the engine running high enough. After a couple of km the dashboard lights started to dim, so I tried reving it as high as I could, but the battery wasn't able to buffer the power and supply the ignition system, so the engine stopped. It was rush hour and I was in the middle lane, so it wasn't a particularly fun wait for the tow truck.
Now that tickover and fuel injection is computer controlled or we have EVs, and there's a far heavier electrical load in all cars all the time, you never notice any more. They all take power, and decrease fuel efficiency.
(but be careful about driving fast in the rain)
I can be very critical of Tesla but if there's one thing they achieved it's making electric vehicles that look cool. I don't think many teenagers saw a Prius as an aspirational vehicle but I'm pretty sure you could find Tesla posters in many a bedroom.
The claim that "the electromagnetic moving block induces minimal friction" says very little considering you achieve the exact same effect with a classic wiper arm mounted on a single electric motor. You probably want more than one arm anyway.
I wonder though if it's the right marketing move and the right deployment of resources.
Car manufacturers found out a long time ago that car sales are not driven by these types of improvements. Cars are purchased emotionally and to a lesser extent functionally. Obviously a Tesla is an emotional purchase since it doesn't really make sense for most buyers to burden themselves with the higher price and inconvenience of an electric car. This seems a great deal like a little icing on the cake of 'we are just a better purchase down to this type of detail'. That's separate from the GP assertion that there is little power savings.
Sure it gets employees thinking of power savings (similar to when Apollo was done everything mattered down to the last detail). But the development and implementation of this is not trivial and it will take meetings and decisions and testing. What else could be done with those resources?
See also the Model 3's AC vents. Whatever their utility & whether its better than traditional ones, they are cool and futuristic and do their part to help the car stand out from the pack. Start adding all these up and you have something.
Car companies outsourced all these types of parts years ago, which severely limit their ability to pursue these types of innovations. That made economic sense when they were competing against organizations with similar cost-cutting strategies, and are a product of the era in which those choices were made and the business climate that encouraged those choices, but it leaves them at a disadvantage when a company takes a very different, tech-driven, vertically integrated approach to product.
When doing motor control work and dyno testing, one of the challenges is measurement of mechanical power (and even electrical) because you need to measure up to -200kW but you care about differences of 10s of Watts.
Heavy cargo & towing can push my power usage up to 50 watt hours per mile. Note that all numbers are based on no pedaling.
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.
(Two other solutions exist. One is spinning the window, you'll see it on ships. The other is making the window hot.)
An example, as used for machine tooling but the exact same mechanism used on ships: https://www.youtube.com/watch?v=YPVBnBK09OM
There are two more solutions I can think of: hydrophobic coatings, and blasted air. I believe these both perform quiet well in less intense rain. Unfortunately both of these suffer from performance degredation from dirt/bug/bird poo etc, so not a perfect replacement to a traditional wiper.
Or using a monitor for the 'windshield' and cooking up some way to keep the camera lens clean.
Put it behind a piece of glass?
Many airliners already use heated window panes for de-icing. Heated windows don't work all that great in a downpour, and wiping is a simple and faster acting alternative.
Blasted air is used minimally for windscreens, but it's a common plane de-icing method for the rest of the vehicle.
The complexity and weight of using spinning windows on planes makes that idea a non-starter.
hydrophobic coatings are also in use, but are generally avoided for the duty of primary windscreens due to most hydrophobic coatings lacking durability to physical stress and contact.
The wipers are costly in terms of excrescence drag, and if there was a better way they'd do it.
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.
[1] https://www.tesla.com/blog/all-our-patent-are-belong-you
That's a little bit different than, say, Toyota, which offered to licenses out their patents royalty free with no strings attached and even offer consulting on how to use them for a fee. There's some guarantees there (or can be negotiated) that the tech/goodwill won't disappear on a whim.
Toyota announced the patent release five years after Tesla, and its mostly for technology released in 1997 for the Prius, hardly anything revolutionary now. By the way if you manage to find their contact form re. this, it says "We have closed accepting inquiries for technical support."
Some Mercedes models do this. The wiper shifts inward toward the middle of the stroke.
Do you mean like door handles?
Presumably because it looks cool.
I've never driven one, but a bit of research indicates that it has a right control stalk but Tesla didn't make it control the wipers. Instead, the button on the left stalk will wipe once. The fact that videos like this exist shows just how horrible the UI is:
https://www.youtube.com/watch?v=1Rr_XzzJ6gc
I'm surprised Tesla could do this, because there are laws that dictate things like what the steering wheel should do, and the order of the pedals and transmission shift pattern (perhaps not so applicable to an EV.)
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.
Still waiting on that.
https://www.nytimes.com/1988/09/10/business/patents-ultrason...
https://www.autoblog.com/2013/12/17/mclaren-ultrasonic-winds...
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?