crazymjb

We have not yet purchased our TL and I was wondering how the wipers work with rain sensors. What exactly do they do? Also, do they work in snow. Thanks. Sorry if this a repeat post.

Treblig

Sensor measures moisture on the glass through light refraction, so I've been told. But the TL doesn't have rain sensing wipers..

EleVatE

http://auto.howstuffworks.com/wiper.htm

I dont think the TL has it... but I think it'd be cool if it did... so tell me im wrong and i'll be happy.

KJSmitty

The TL doesn't have "rain" sencing wipers it has "speed compinsated" wipers. Basically depending on the setting when you come to a stop they slow down (more delay), then speed back up (less delay) once moving etc.

VelfarreClubber

Yeah, thats what i thought/noticed

pbm317

off of the original topic... but i love the wiper style that the german cars are using. Like BMW and Audi... where it's one big piece, with no metal frame. Do you guys know what I'm talking about?? I noticed the new Cadillac STS has them as well. I know it's small.. but yeah I like that kinda thing.

DarkWraith33

They're called Valeo Ultimates... Tirerack my friend. Big money but VERY GOOD wipers... Trico DOES make a near replica that my friend loves on his Audi... (They are MUCH cheaper)

http://www.tirerack.com/accessories/valeo/ultimate.jsp

Check it out. I plan on getting these soon.

ITL

Wow, $39 per wiper blade.....wonder how much cheaper the Trico is?

DarkWraith33

My friend said they were like $13 a piece at Pep Boys... I did not see them at PepBoys and I am not sure how they differ from the Valeo's... I'd like to hear from someone who has the Valeo's on how good they are... And how long they last... If they would last 2 years... Done deal, I'll drop the money. But if they are like normal wipers and last 6 months, no way...

ITL

or you could just get one at a time...lol















just kidding

go_blue

The VW "Tow Rag" has these one-piece wipers. Hey, a Luxury VW SUV......

EleVatE

I guess thats cool... but if I had my own custom car I would have windshied wipers like those on the lexus in the movie minority report. The car was actually produced



you cant see it very well there, but you get an idea of what the windshield looks like. There is a vertical windshiled wiper like | that moves horizontally across the entire windshield before moving allt he way back, and it hides on the side of hte window when not in use.

Oh that window that is being shown best in that is the front window, and the wheel closest to you in the pic is the front wheel.

crazymjb

I still the think the blower Idea has a fair amount of potential. The only thing is it seems liek it would rob the engine of more power. But if you are driving in the rain you shouldnt need that extra power. It would also be interesting if they had an efficient way to superheat the windshield so drops would evaporate on contact.

EleVatE

I dont think thats really practical. If you have ever been in heavy heavy rain... that would have to be one heck of a blower, haha.

For it to be that hott... you'd have a temperature difference between the window glass and the indside temperature and that would cause condensation.

Not to mention where the heck you would put the air duct that would run the whole length of the bottom of the window.

crazymjb

hey, its on acura prototypes. there was also something in pop sci about it.

pbm317

Thanks for the info on those wipers. They're on the brand new Avalon too! man.. hahah

anyways, about heating the windshield, I've noticed several high end cars that have lines in the windshield, maybe more for purpose of de-icing it? I've see it on the Land Rover LR3 and the Range Rover, as well as some Mercedes models I think. Very faint lines, nothing like the lines on rear windows.

crazymjb

Oh yah, that is common, I was referring to having it at 300+ degrees all over to repel water.

ONAGER

i can see the lawsuit now... either some dumbass (not unlike myself) would touch the glass and burn himself, just to see if it gets hot....

or some women was taking care of "something" when her ass hits it and gets burned....

cool idea but it will probably never happen

acugirl

Any optical engineers here? The pdf file on "How stuff works" says that the sensor evaluates the amount of water on the windshield by shining infrared light and measuring the amount of light reflected back. Now, they claim that if there is no water on the windshield, more light comes back than when there is water. Why would this be so? Using my college understanding of physics of light, here is what I figured out (please, correct me if I am wrong).

When light hits a boundary between two optical materials that have different optical density, the light gets both reflected and refracted. The exact amount of reflection depends on the ratio between optical densities. Larger ratio means more reflection. If there is water, the ratio between optical density of glass and water is smaller than between glass and air => less light is reflected and more light passes through. And this difference is what the sensor measures.

In a sense, the water acts like antireflection coats on camera lenses - more gradual change of optical density due to layers of antireflective material => less light loss due to reflection and more light passes through => better lens.

Oil Fighter

ok, think about this, if we have a super heated windshield, it would also mean that we have this giant heater the size of the windsheild, can you imaging how HOT the interior is going to get everytime we use it?

EleVatE

"when moisture strikes the windshield, the system experiences an interuption to its infrared beam"

Indicating, like you said, that when there is moisture, the beam is interupted.
On the How Stuff Works page 3 it says:

"The sensor projects infrared light into the windshield at a 45-degree angle. If the glass is dry, most of this light is reflected back into the sensor by the front of the windshield. If water droplets are on the glass, they reflect the light in different directions -- the wetter the glass, the less light makes it back into the sensor."

Ok so... for easy sake lets say your front windshield is at a 45 degree angle to the road. The beam for this system is either projected horizontally or vertically, i dont think it matter which. But we are going to say vertically. Then... when it hits the glass at a 45 degree angle, it is reflected, not refracted to another sensor which would be looking for the signal coming in horizontally. So give your glass some thickness and look at it from the side, so this is your glass: // the beam would be projecting off the First slash... the OUTSIDE, or front of the glass. Now... not all the light is going to be reflected... But if there is a water droplet right on the outside of the windshield, the water is going to refract the light even more, and not as much light is going to return to the sensor.

At least thats what my physics knowledge says....

acugirl

Yes, this is what I meant. More light gets refracted when there is a water droplet because the boundary water/glass refracts more (and thus reflects less) than air/glass boundary because of the different ratios of optical densities.