HUD or heated windscreen

[Snoodini]

Originally Posted by Clan

all new volvo models since 2004 have a PTC electric element in the heater ...

Clan, I again ask if you can provide a part number for the PTC heater for heating the air which I believe does not exist.

To be clear. I am pretty certain that there is NOT any form of electric heating for the HVAC system on SPA cars.

I'm happy to admit I'm wrong if proven otherwise.

[Clan]

Originally Posted by Philip Fisher

Yes but you are not comparing apples with apples here.

Heated rear screens have been around for, as you rightly point out, ages. The wires were very obvious and would not be suitable for a front windscreen on a regular production road car.

Heated front windows were brought to the mass market in the UK by Ford in probably the mid to late nineties. I guess the key bit of tech was getting the wires thin and unobtrusive enough so as to be broadly acceptable to most drivers. Volvo was (or was soon to be) owned by Ford and I struggle to see that there was not some technology transfer between the companies.

The assertion that there were viable heated front screens on the mass market in the UK from the 60s is - I would suggest - wrong.

No Philip , what i am describing from the early 60's is exactly the same technology as on your volvo ... I'm not here to lie to you, I have always been here to educate you , I was there and had one on my 1967 Sunbeam Imp sport .. It was an optional extra from the competition department for Rally cars as car demisters then were not that efficient. Minis soon followed suit . you saw the document picture I posted from 1967 ... The Printed screen elements came in the early 1970's as they were far cheaper to make .

[Clan]

Originally Posted by Philip Fisher

So I have just googled PTC heater and came across this:-

https://www.volvoclub.org.uk/faq/Eng...html#PTCNipple

It describes the PTC heater as a small heater which heats air coming out of the crankcase vent and prevent throttle icing. I am slightly lost in the detail as I am not familiar with this part of the car. I have, however, found nothing which describes the PTC element as "an electric element in the heating system for quick warm air". It seems to be a small heater which aids the function of the car in very cold weather by preventing a very specific part of the cars breather system from icing up.

But maybe I am wrong. Perhaps Clan you can reference a document which describes the PTC heater in the terms you have used as a heater for quick warm air?

You just need to read your handbook where it says :

Electric additional heater

Cars used in cold climates have an electric additional heater integrated into the car's
climate control system.
In a semi-cold climate zone cars
have an electric additional heater instead of a
fuel-driven version.
The heater cannot be controlled manually but
is instead activated automatically after the
engine has been started in outside temperatures below 14 °C and is switched off after the
set passenger compartment temperature has
been reached.


In practice it is in UK cars what do you think those heavy duty Red and black wires are for in the passenger footwell under the carpet hear the heater ?

That is why I say that a heated front screen is a marketing tool and so would anyone else who has experienced the remarkable defrosting properties of volvos without heated screens .

PTC element (Positive Temperature Coefficient)

On some markets with a cold climate the vehicle uses a PTC element as an extra heater.
Even four cylinder engines, in some cold markets, use a PTC element. The PTC element is also available as an option.
The PTC element heats the passenger compartment quicker at lower outdoor temperatures. This is essential as the coolant does not emit sufficient heat, especially during the initial minutes after the engine has been started.
The PTC element is placed in the climate unit after the heat exchanger. It is accessible from the front.


The air that flows past the hot PTC element, on its way into the passenger compartment, is heated directly.
Typical characteristics of a PTC element:

fast heating directly after start
high degree of efficiency
lightweight, compact design
cannot be overheated
maintenance free.

The PTC element consists of small metal coated ceramic plates (1) sandwiched with radiator elements (2) of aluminium. These layers are held together in a frame (3) of a spring element. The aluminium element has the task of conducting current at the same time as it transfers heat to the air flow.
The maximum output of the PTC element is 1250W.

The PTC element has a positive thermal coefficient. This means that the resistance value is relatively small at low temperatures and increases with the rising temperature.
When the cold PTC element is voltage fed, the current is high during the initial stage and heats up the element. With a rising temperature the ceramic's resistance value also increases whereupon power consumption drops.
It takes approximate 20 seconds until the stabilisation current is reached. The ceramic temperature is dependent on the heat output and the ambient temperature. With good thermal dissipation the temperature drops and with that the resistance. This results in an increase in power consumption and with that an increase in temperature.
If a small amount of heat is emitted to the surroundings, the temperature of the ceramic rises and with that the resistance. Through this cycle the heating element is regulated with its own power consumption. The result is an equilibrium between the supplied electrical energy and the emitted thermal energy.

The Climate control module (CCM) controls, via the Central electronic module (CEM), the function of the PTC element. For more information, see Design and Function, Climate control module (CCM) and Design and Function, Central electronic module (CEM).

[Snoodini]

Originally Posted by Clan

all new volvo models since 2004 have a PTC electric element in the heater ...

What manual are you looking at? I can not find any mention of an electric heater in any SPA car manual.

Again... there is no evidence of PTC heaters in SPA cars. Please provide your sources to prove otherwise

[Clan]

Originally Posted by Snoodini

What manual are you looking at? I can not find any mention of an electric heater in any SPA car manual.

Again... there is no evidence of PTC heaters in SPA cars. Please provide your sources to prove otherwise

sorry i didn't realise we were talking about the latest models although I see no reason to think they would have deleted it , You look both sides of the heater behind the side panels and see if there are heavy red and black cables going to it ... You could put a thermometer to measure the temperature of the air coming out the vents from a cold start on an icy day ..

[Philip Fisher]

Originally Posted by Clan

sorry i didn't realise we were talking about the latest models.........

This is a forum for SPA models......

[Philip Fisher]

Originally Posted by Clan

No Philip , what i am describing from the early 60's is exactly the same technology as on your volvo ... I'm not here to lie to you, I have always been here to educate you , I was there and had one on my 1967 Sunbeam Imp sport .. It was an optional extra from the competition department for Rally cars as car demisters then were not that efficient. Minis soon followed suit . you saw the document picture I posted from 1967 ... The Printed screen elements came in the early 1970's as they were far cheaper to make .

I am sorry but I have no recollection of any production cars sold in the UK in the 80s or early 90s with a heated front screen. Ford were then first to market with their quick clear fully heated screen perhaps in 1996. Others then followed.

Perhaps there was some sort of early prototype in the 60s as you say, but the current technology of fully heated screens with tiny almost see through lines was brought to market by Ford in the mid 90s.

[GJB]

You have put the problem with the heated windscreens when you mention the fine lines if the sun or headlights are in the wrong direction its like looking through bars thats why I would never buy a car with a heated windscreen if the choice is head up display it would be my choice every time.

[Clan]

Originally Posted by Philip Fisher

This is a forum for SPA models......

To answer your question Yes you DO have a PTC electric element in the heater on SPA cars as I thought , the XC90 also has them in the rear side ducts .

[Clan]

Originally Posted by Philip Fisher

I am sorry but I have no recollection of any production cars sold in the UK in the 80s or early 90s with a heated front screen. Ford were then first to market with their quick clear fully heated screen perhaps in 1996. Others then followed.

Perhaps there was some sort of early prototype in the 60s as you say, but the current technology of fully heated screens with tiny almost see through lines was brought to market by Ford in the mid 90s.

Triplex were marketing their Laminated Electric heated Front screen for cars from the mid 60's with exactly the same construction as today with the "invisible" wires between the layers of Glass , cars I know of with them were Hillman Imps and minis , and ford escort rally cars . I first saw them as rear heated screens on a big Rover saloon rear screen from the early 60's

I suggest you search for Triplex Electrically headed windscreens . I have spent more than enough time on you today trying to educate you .