Heat related questions-ideas.

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James.UK
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Joined: 15 Dec 2003, 00:12

Heat related questions-ideas.

Post by James.UK » 04 Mar 2004, 20:53

Hi All.. Two points I would like to raise for discusion.. [?]
(1) Would it be possible to relocate the temp guage source to a better position? The thinking here is, if the sensor gets dry it cant read the water temp, so why not move it to a place where it will not be in an air pocket as soon as the car starts losing water? Option "B" I would have thought someone makes sensors suitable, that could simply be attached externally somewhere near the places most likely to get overheated first? Cylinder head?
(2) Would it be possible to use water soluable oil in the coolant? I worked in machine shops for many years that ran cooling fluid onto the work in progress to keep it cool via a pump, I never saw a pump break down? I never saw any machine show any sign of rust, some of those machines were 50+ years old. So:- Would adding soluable oil lower-raise the coolant boiling point? is there some other problem I dont know about?
Also would this soluable oil idea work in our home central heating systems to protect pipes and pumps?[?][?]

tomsheppard
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Post by tomsheppard » 04 Mar 2004, 21:20

Yes, Yes, YES! One of my hobby horses. I don't know about the oil cooling, or indeed if there is such a thing as water soluble oil (they don't mix- you get emulsion. In the rad, this is bad news!!) I Do know about the LM35 which is a little chip the size of a transistor and the cost of less than £2 which gives an output of 10mV/degree C. These little beasties give very accurate outputs and are accurate to the degree (according to device spec.)
You will need a 5 volt regulator chip to use it in your car, then take the output of the LM35 to a DMM (little yellow digital multimeter, usually less than £5 for the cheapest ones you can get. That's all you need. Don't pay £25, £3.99 is more like it. These are similar to the one I use professionally except for the price tag which is a matter of adding two noughts!) Bingo, Spot on temperature readings for £10, Embed the connections in Epoxy to form the whole lot into a bead and if you glue it to the top of the head, then you will know the head temperature. The output of some chips is related to Kelvin and so reads 293 degrees high but there is a dodge to get around that. I suggest that you call up the web using LM35 Datasheet (or LM35Z)to find out more. Two of these devices, switched could use one meter so that you could monitor temperatures in more than one place on the engine, This could tell you when or if the stat is open/opening or, more importantly, when the dratted thing has got an air pocket!
The 'tronics are really quite simple, so it is well worth a look.
I might even get around to posting a diagram on my site but don't hold your breath, I'm busy for the next month- fixing up a BX!

RichardW
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Post by RichardW » 04 Mar 2004, 21:40

Tom,
Sounds interesting, but the difference between Kelvin and Centigrade is 273°.....

tomsheppard
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Post by tomsheppard » 04 Mar 2004, 22:06

Slip of the finger, to my shame!

James.UK
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Post by James.UK » 04 Mar 2004, 22:50

Soluable oil is, or was, in general use in every workshop I ever worked in, the mix is called "slurry" down south, "mystic" up north.. When you add the oil to water it goes white in colour and has a very oily texture.. Used in lathes, milling machines, borers, planers, grinders etc etc to keep whatever you are machining from getting too hot.
Hi Tom, could your idea be produced in a commercial form? i.e. Could it be sold as a kit with simple instalation instructions? [:)]

tomsheppard
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Post by tomsheppard » 04 Mar 2004, 22:58

Yes it could but I really couldn't be bothered to do it myself - I have a life, you know! Far better that I rig some simple instructions on the web. Better still, follow the suggested search and DIY. There is really nothing here that is beyond the average Citroenaut and If you profess to know nothing about electronics then that is no excuse- it is easy enough to learn at this level. The link is http://weber.ucg.ie/tech/datasheets/lm35.pdf.
The LM35 as I said is like a transistor. I just checked and they work to 30 volts and an accuracy of 1/2 degree. They output in Celsius
so 1000 mV= 100degrees C the device is the shape of a capital D and if you hold it with the leads facing you and the orientation as the capital D, the top lead goes to car ground. The middle one goes to meter red and the bottom one goes to battery plus. It will not flatten the battery. The black probe of your meter goes to car ground. That is all there is to it. choose the millivolts range on the meter and draw on a decimal point for the last digit. The chip reads up to 100C for an LM35D but all the other versions do 110+
Maplin, Farnell and Radiospares (sorry, RS components) carry them.
You will know somwbody with an RS account. Ask around your professionally techie friends.

James.UK
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Post by James.UK » 05 Mar 2004, 00:29

I was thinking more in terms of you making a few bob out of what is a good idea.. :-)

tomsheppard
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Post by tomsheppard » 05 Mar 2004, 13:54

I do all right!

James.UK
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Joined: 15 Dec 2003, 00:12

Post by James.UK » 05 Mar 2004, 18:56

[:p] Good! lol.. [:o)] [:D] Re ask a techie friend, I did, he said that some Golfs have an in-line system that reads from more than one location, but not sure off hand how it works-will get back to me on it. Sounds interesting. [8)] [:)]
So.. Anyone know what effect adding the soluable oil to the coolant would have?
And.. Anyone know where I can aquire a detailed diagram-drawing of the water circulation system on a ZX? [8)]

James.UK
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Post by James.UK » 05 Mar 2004, 20:13

I have just had a chat on the phone with a thermal-liquid conductivity Lecturer at UMIST. (Manchester UNI) [:D] Apparently, given time, the soluble oil would form a coating on the walls of contact points, i.e. interior of pipes, matrix, etc etc, and this would act as an insulator,and reduce the efficiency of the cooling-heating system. (ratio of soluble oil to water mix varies dependant on requirements between %3 and %10, for the purpose I had in mind %3 may even be too much).
He did add, that this is purely theoretical. To his knowledge no one has physically put this to the test to ascertain how much effect it would actually have in practice. Interesting huh. [:)]
In a large bore heating system it might be a good trade-off in terms of cost? very slight reduction in heat radiated against less maintenance required on pipes and pumps..
Bearing in mind oil thins when hot, and we only have a very small percentage of oil in the mix to start with, it would be interesting to know how much effect the oil coating would really have? %0.0001 maybe? lol. Its a shame I don't have an old engine to play with. erm experiment on [:o)] [:D]

Dave Burns
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Post by Dave Burns » 07 Mar 2004, 07:18

Soluble oils soon end up creating a thick slurry at the bottom of the tanks in machines, though this is partly down to contamination by tramp oil from slideway lubricant.
It would almost certainly destroy the rubber pipes in the cooling system, which are not normaly made from oil tollerant rubber.
Have a look at this:
http://www.evanscooling.com
But its not available over here unfortunately[:(]
Dave

James.UK
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Post by James.UK » 07 Mar 2004, 08:41

Hi Dave, thanks for the information. :-) [:)] It certainly looks interesting stuff.
Re not available here, have you contacted them? Do you know why we can't get the stuff over here?
Logicaly if we could use the stuff it would pay to replace our cooling system pipework with new or we still leave ourselves open to burst or leaky pipes causing blown heads or worse. But with a reduced pressure system and new pipes it would go a long way toward our engines actually being fairly safe from overheating for quite a long time!! [:)]
Re the soluble oil we do have available, it does appear it wont work in engines, if we replaced all rubber hoses with oil impervious pipes we are still faced with a lot of 'unknowns'.. (I still dont know what effect it would have on boiling or freezing temperatures) but maybe using it in central heating systems is still an option? ..
I am very surprised it hasn't been put to the test by 'someone' and the results documented. Or is this another case of 'them' not bothering to find out because 'they' prefer things to wear out so we have to constantly replace them.. [:(!]

Dave Burns
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Joined: 14 May 2001, 05:30

Post by Dave Burns » 07 Mar 2004, 19:48

Yes James I asked the question over a year ago, they didn't have any plans to get the stuff over here then, doubt if anything will have changed, I'd certainly give it a whirl.
Dave

James.UK
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Post by James.UK » 07 Mar 2004, 21:58

Thanks again Dave. I have emailed them and intend to phone them tomorrow, I will post the results of the email and conversation here asap.. :-)

James.UK
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Post by James.UK » 10 Mar 2004, 23:14

UPDATE I have spoken to the USA Co that make the coolant.. It WILL be available here very shortly.. [:)] the big question is -- at what price?? hhmm..
Our talks are on-going so I will keep you all informed via this thread....