Windscreen Wipers

Posted by: boxer

Windscreen Wipers - 25/06/2005 07:49

I've just been round the Scottish Highlands in my new Renault Megane and rain has been a preoccupation, whilst the rest of Britain has been sunbathing.
It has automatic windscreen wipers, which are 100% effective: They sense heavy and light rain and move faultlessly from adjusting the intermittent wipe speed, right up to fast wipe: How do they sense? What's the technology involved? - I'm fascinated.
Posted by: mtempsch

Re: Windscreen Wipers - 25/06/2005 08:57

IIRC it works by refraction, sending out a beam that, to an extent, bounces on the (outer) glass/air boundary back to a sensor. When there is water on the glass, the beam doesn't bounce, it just bends a bit, travels through the water and out through the water/air boundary (or at least somewhere else than the sensor...It bends and/or bounces due to the different refractive indices of the glass, air and water.

Edit: Supportive pdf, doesn't go any deeper though.
Posted by: sn00p

Re: Windscreen Wipers - 25/06/2005 15:22

Quote:
It has automatic windscreen wipers, which are 100% effective


Glad yours are better than mine, the ones on my clio are useless. They go slow/turn off when it's raining hard and go mental when it's light drizzle. No amount of playing with the sensitivity switch makes any difference either!

Grr..
Posted by: andym

Re: Windscreen Wipers - 25/06/2005 16:00

Mine were crap too, I always had to keep flicking them off then on again. The smart has a much better programmed precipitation avoidance system, it's called intermittent, much better.
Posted by: boxer

Re: Windscreen Wipers - 25/06/2005 16:46

Quote:
the sensitivity switch

Have I got one of those? where is it? Honestly mine work immaculately.
Posted by: mtempsch

Re: Windscreen Wipers - 25/06/2005 16:52

Quote:
Quote:
the sensitivity switch

Have I got one of those? where is it? Honestly mine work immaculately.


To the best of my knowledge, the one in my Pug doesn't have a [driver operateable] sensitivity adjustment. Might of course be different between brands/mdels.
Posted by: andym

Re: Windscreen Wipers - 25/06/2005 16:57

Mine was on the wiper stalk, on other models it altered the duty cycle of the intermittent mode, about halfway down the stalk.
Posted by: sn00p

Re: Windscreen Wipers - 25/06/2005 17:24

Quote:
Mine were crap too, I always had to keep flicking them off then on again. The smart has a much better programmed precipitation avoidance system, it's called intermittent, much better.


When I asked how you disable it (Make the auto-wipe setting into intermittant mode) I was told by both my dealer and a head honcho at renault that the only way of getting intermittant mode was to replace the whole stalk!

I was amazed, I really couldn't believe that they'd not put it into the ECU, morons! Everytime I go into the dealer I ask about it out of principle, I actually think the auto mode is dangerous.

What's most annoying is that model below mine in the range has got intermittant mode.

Oh for the luxury of intermittant wipe..

As Andy said, on the clio the sensitivity setting is on the wiper stalk, it's a little "swivelly" thing!

(bah humbug)
Posted by: andym

Re: Windscreen Wipers - 25/06/2005 19:02

Quote:
I was amazed, I really couldn't believe that they'd not put it into the ECU, morons!


That's the exact opposite of the Smart, everythings on a CAN bus and as a result a lot of the options you would imagine require hardware changes actually just require a poke of the ECU, both the full auto gearbox upgrade and cruise are a case of adding a button or two to the loom and enabling it in the ECU. I'm sure if you wanted to swap the action of the turn indicators you could do it in software.
Posted by: boxer

Re: Windscreen Wipers - 26/06/2005 11:29

Quote:
I've just been round the Scottish Highlands in my new Renault Megane

I set out to do it in the motorhome, towing the economy car which the boxer family don't allow me to mention by name, preferring to describe it as: "The Sandwich Van".
We had a blowout on the M6 at speed, the most scary thing in 40 years of motoring.
The tyre tread destroyed the protective guard and flailed away into the interior, destroying the gas, water and electricity pipes and destroying the central heating boiler, so by the time the insurers deliberate, we could well miss the whole summer.
However, we had a lovely time in Edinburgh and up in the Highlands, but the expense was, well, expensive.....and the boxers had a week in kennels, which we like to keep to a minimum.
Posted by: bonzi

Re: Windscreen Wipers - 26/06/2005 16:58

Quote:
The tyre tread destroyed the protective guard and flailed away into the interior, destroying the gas, water and electricity pipes and destroying the central heating boiler...

Ouch! This is no matter to joke about, but I was instantly reminded of that ill-fated Concorde.... You are lucky nothing caught fire!

Makes one wonder how safe are those motorhome contraptions (well, I guess they are all over the range, depending on whether they are more camping trailers with engines or trucks with bunks).
Posted by: gbeer

Re: Windscreen Wipers - 26/06/2005 18:59

Quote:
electricity pipes


This is some kind of British slang, right?
Posted by: andym

Re: Windscreen Wipers - 26/06/2005 19:09

Quote:
Quote:
electricity pipes


This is some kind of British slang, right?


He probably means conduit with electical cables running through them. But you're right it does sound like a bizarre name for cable.
Posted by: mtempsch

Re: Windscreen Wipers - 26/06/2005 19:52

Quote:
But you're right it does sound like a bizarre name for cable.


Maybe a subscriber to the "electronics run on smoke" school of thought?
Posted by: boxer

Re: Windscreen Wipers - 27/06/2005 04:14

Yes, and it struck me after bonzi's post that gas means something different in the US: The stuff that drives the engine, which might well have caused a fire, is unaffected, the stuff that we use for heat and cooking is completely severed - in Europe, it's illegal to travel with it connected anyway, the gas cylinders and the diesel tank are both at the front of the vehicle.
....and the electricity pipe was an oversight on my part!