Coolant flow sensor

[20B]

I am running a davies craig electric water pump running a water temp sensor and coolant pressure sensor. I want to install a 'flow' sensor that can basically measure if the water pump is working and flowing coolant around the motor and at what rate, I have had a bad experience with electric pumps failing and not being able to detect the rise in coolant temp quickly enough.
There are several industrial units availiable but would be interested to see if anyone else has done the same thing.
I would prefer not to use ultrasonic but something more cost effective like a paddle wheel type sensor.
It will be connecting to an SDL or M800.

[DarrenR]

I don't know of an actual flow meter you can use, but the paddle wheel type with hall or mag output would be fine to connect to an SDL speed input. Some mag type do have a very small output so you will need to make sure it will generate at least ~0.05vpp.

A cheaper option again would be to measure the electrical current draw of the pump. If the pump fails it is very unlikely the current it draws will remain the same. Depending on how they fail - stalled, loss of drive, broken wire etc. will have a different effect on the current drawn. You could even detect a failing pump, if it's starting to seize up, or burn out, or impeller slipping the water will still be pumped but the current draw will change.
Current sensors are available that change a current into an analogue output voltage.
If you're handy with a soldering iron, this is a cheap and accurate current sensor -
http://www.sparkfun.com/commerce/product_info.php?products_id=9028

Or you could always just fit a PDM

[IJ.]

Biggest failure with these things(EWP110) seems to be the seal leaks, DC released an upgraded version with a Carbon seal and after 12 months use it also leaks....

The Motor's seem fine and quite reliable.

[Martin]

ive seen seal leaks aswell. Dont run them dry.

Ive removed all control circuitry from the pump and im using PWM output to vary pump speed from the Mx00 for ET read by the ECU. Its done via a solidstate relay, before the DHB was available.

[Daniel]

Current sensors are available that change a current into an analogue output voltage.


So how do you wire this to a M*00 ECU?

I removed a current sensor from a VE holden that has it on the Earth
wire or thats what i think it is.

Daniel

[DarrenR]

I don't know about the VE commodore one,
but the one i suggested above, '+IN' is connected to the pump motor supply voltage, 'GND' to the Mx00 0v sensor ground, Aout to an AV input, '+OUT' to the motor.
The calibration is 0V = 0A, 3.3V = 90.15A

[Blu302]

Would measuring the pressure differential across the pump inlet/outlet be suitable as i am looking at fitting a Mezirere 55Gph to my 302W and would like to monitor for failure as well.