Say Shep - in an earlier post you mentioned

1873 Views 10 Replies 3 Participants Last post by marshallf3, Oct 2, 2010

marshallf3

Discussion Starter · Sep 30, 2010

Both my CX have a nominal running temp at the cylinders of 85 Deg C +/- say 5% or less.

You also mentioned that you've got one of those IR non-contact thermomemters.

Any possibility, when you get a chance, that you could take a temp reading at the bottom of the radiator (by the exit hose) to see what water temp is coming out when the bike is running at what you'd consider to be around ideal?

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marshallf3

Discussion Starter · #4 · Sep 30, 2010

Shep said:
I've just run one of my CX up to idle+.It's hard to get a really accurate figure because of variables.My 85 Deg C reading the heads was on a very warm summer day after a good ride so the whole bike was hot,if you get my drift.Just done some now and my heads,once the fan cuts in,are at 75 Deg C even and the ambient day temps are 16 Deg C.

Before the temp started rising above the nominal mark the bottom of the rad cores was between 60/65 Deg C.After the fan had kicked in and I let it drive down the temps the cooling pipe and rad bottom settled around 65/66 Deg C.

I'll try and remember to do some more after a ride as that will give a better reading of normal use,not just stood idling before a ride.

Thanks, this is exactly the type of information I need and, oddly enough, close to what I expected. In addition it would be nice to know the hottest temp you can read from the radiator at the same time. Might be able to "point and shoot" the upper radiator fins through the grille, bet we're going to find a reading of around 85*

I think you decided that since you've got some air space around your switch the actual water temperature going in would be around 10* or so higher than the 70* switch you're using?

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marshallf3

Discussion Starter · #6 · Oct 1, 2010

Shep said:
I settled on the 75 Deg C one to allow for the difference between the engine and the rad.I have to be honest and say again that you are really complicating a very simple thing.

The electric fan is not meant to nor needs to regulate the cooling system.It is there,as in cars,as a device for cooling the system in adverse,warmer than air-cooling,conditions and stop the engine overheating in those conditions.

This simple circuit will do the job and can be tuned,

http://www.heatsink.info/content.php?content=control.shtml

It really doesn't matter about the Hysteresis and that the above circuit is basically an,"On-Off" circuit(It will by the nature of component tolerances have some hysteresis anyway and the time it takes for coolant to move etc).

If it was set to switch the fan on say just before the middle of the temp gauge the fan will drive down the engine temps and then it would switch off.Yes it may switch on and off a few times in traffic but that's not a problem.As soon as the engine gets air cooling the Efan is then redundant.

I did build that circuit and it does just behave like a switch.

I realize what I'm building sounds a bit complicated but it's easy enough to build and will have several advantages like an indicator that signals a fan fault or overheating as well as a remote temp gauge output for those popular dot/bar circuits. Besides that it's a gadget and I, like a lot of others, like gadgets.

Probably add a lot of peace of mind to the 650 owners as well.

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marshallf3

Discussion Starter · #8 · Oct 2, 2010

Shep said:
I've just run one of my CX up to idle+.It's hard to get a really accurate figure because of variables.My 85 Deg C reading the heads was on a very warm summer day after a good ride so the whole bike was hot,if you get my drift.Just done some now and my heads,once the fan cuts in,are at 75 Deg C even and the ambient day temps are 16 Deg C.

Before the temp started rising above the nominal mark the bottom of the rad cores was between 60/65 Deg C.After the fan had kicked in and I let it drive down the temps the cooling pipe and rad bottom settled around 65/66 Deg C.

I'll try and remember to do some more after a ride as that will give a better reading of normal use,not just stood idling before a ride.

Actually "not moving but fan on" gives me a pretty good low point, apparently the CX is quite happy getting 65* water back from the radiator if the heads were still that cool. Do you recall what the bike's temp gauge was reading at the time if you still have one?

I'm getting very close to having this on paper as a buildable device.

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marshallf3

Discussion Starter · #11 · Oct 2, 2010

Thanks Shep, that's plenty of data because, as you've noted, all we're trying to do is control a simple fan to come on when it's needed. I'm just thinking I'd like a continuously variable speed option better than a simple on/off situation.

ponderbuzzard said:
Here is a quick and simple temperature gauge. Auto parts stores have mechanical water temperature gauges for $15.00 US. Select one with a cylindrical probe sized to insert well into the spark plug hole water drain on the bottom side of the cylinder. Use Epoxy or RTV type gasket maker material around the probe to hold it in place. String the probe lead up to the handle bar using the path of least resistance, and cable tie the mechanical meter just below the tachometer, or wherever. There's also a light bulb that can be wired in if you believe in the necessity of observing cylinder temperature in low ambient light condition, the dark. You might be surprised at the delta temperature on the cylinder, or how much the temperature varies with engine rpm, bike velocity and how long cool down takes, when the engine is turned off after a power run. The mechanical fan at 550 rpm does not move significant air at idle. I ride sometimes in ambient air temps exceeding 100F, 38C and extended idling is not good in those conditions. That alone would be a recommendation for an electric fan.

Interesting idea for a temp gauge, but that fan controller I'm building will have an output to drive the popular dot/bar display or if I wanted to get fancy I could design the circuit where it would output about anything voltagewise to drive a different type of meter. The sensor involved outputs an accurate 10 mV per degree centigrade so 85*C would put out 0.85 volts. Very low power though. The circuit can also be designed such that it outputs in *F but it matters not in this circuit as it's just to control the fan speed.

The displays look like this: http://www.mouser.com/images/avagotechnologies/images/91284.jpg and are available as single colors or set up as

GGGYYYYRRR or RRYYGGYYRR (with G = green, Y = yellow and R = red)

Ideally I'd like to make a small module that would incorporate one of these with a selector switch so it could not only serve as a relative temperature gauge but also a voltmeter, an ammeter is possible or just about anything else one wanted to monitor. It's going to take a lot of thought if I try to make something universal as the only color scheme that would make sense would be the one with the green bands in the middle.

Then there's the size involved and all the different bikes. For mine an extension of the fuse box cover would make sense, that could even give me room to include a rotary switch that could select between several functions. A smaler one could be made if it only had to select between two items such as relative temperature and a voltmeter. As with anything finding a decent mounting place that doesn't look strange is a challenge.

So .... when I get things the way I like them I'll be writing up what I've found and how well it works.

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