# Controlling Pierburg CWA50 speed



## Tomdb (Jan 28, 2013)

Arduino, so simple to program and use if you know any code. 
Plus others might be able to help, I did some programming for a pierburg pump.


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## GoElectric (Nov 15, 2015)

I believe that pump requires some 1-wire serial communications to get it up and running for PWM: some protocol like "Lida?" 

70 Hz seems like it would be too slow as well - I just pulled-apart an Aisin 3 phase PWM pump and the PWM controller chip spec said "over 16khz". i believe you have to PWM at faster than the max speed of the pump (pole-wise).

In my search for info on controlling the Asin pump I was given an extensive write-up on controlling the Pierberg pump; I think it came from the EVTV forums. Have a look there, and I'll see if I can find the source as well. 

Receiving two new PWM pumps next week, as the Aisin pump has still not cooperated, but interested in anyone's progress on any pump, as I would still like to master the Aisin.

Cheers.


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## Tomdb (Jan 28, 2013)

http://webpages.charter.net/n8nxf/EVTV%20Pierburg%20CWA-50%20Coolant%20Pump.pdf

Nope EVTV document states differently, plus it has been confirmed by others.
signal 45-1100 HZ, duty cycle 13-85%


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## oudevolvo (Mar 10, 2015)

Yes, that is the 'interesting link' I was talking about.
That guy found out the EVTV pump (which is the Pierburg) does not like higher frequencies.

Arduino sounds a good approach to explore.
I am at least eager to learn and do have some experience in programming.
At an earlier stage I also came across Arduino as an option and made some relevant bookmarks.
It looks like there is quite an active community.

First step is to select the proper version to start with. 
Next changing the PMW frequency since by default Arduino is running much higher. I will keep you updated on my progress (and questions).


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## oudevolvo (Mar 10, 2015)

Tomdb said:


> Arduino, so simple to program and use if you know any code.
> Plus others might be able to help, I did some programming for a pierburg pump.


Did you do programming for a Pierburg pump on Arduino?
I am exploring using Arduino and so far it looks promising.

If you controlled a Pierburg from Arduino, did you use level translators?
Arduino output is only 5V.
I assume the PWM input signal for the Pierburg needs to be 12V, correct?


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## Tomdb (Jan 28, 2013)

yes the pwm needs to be 12v, use a simple transistor drive.


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## oudevolvo (Mar 10, 2015)

Update: I got it working!
I can now PWM control the Pierburg CWA50 pump speed based on a measured temperature.
Works perfect using the default Arduino Mega PWM frequency.
Details, photo's and video in my blogpost Controlling Pierburg CWA50 pump using Arduino successfull


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## GoElectric (Nov 15, 2015)

Hi Lars,

That is great! I can't remember seeing it, but you must be using a flow meter? We have one on order. Using Arduino as well. We have our heating system working very well too, but as there is no cooling required have gone with a smaller pump. Still fine-tuning optimal flow-rates for different heating requirements, but 240W heater, to get the water up to a reasonable temperature the pump has to be turned right down.


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## oudevolvo (Mar 10, 2015)

Yes, in this test setup I just used a very cheap plastic hall sensor.
For implementation in the car I want at least a brass one and perhaps a little bigger in inner diameter and perhaps even contactless.

You won't be implementing any cooling capacity?
I was planning to add a radiator that I can include/exclude in the loop.



GoElectric said:


> ....has to be turned right down.


Sorry, it's probably my English reading but can you elaborate on that?
I was planning on using a 2000W heater but bought a Defa 1000W that came by cheap for testing purposes.


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## GoElectric (Nov 15, 2015)

Hi. No, no cooling for me, as I have a much smaller motor than your's and won't be fast-charging. 

With a 1000 or 2000W heater your situation is different; I have to SLOW DOWN the pump considerably to heat the water as it flows through the 240W heater, otherwise there is no delta-T and no heat-transfer. I think you will also have to find the optimum pump speed (too slow: boil water/too fast, won't heat water sufficiently), as pump full-speed will not be optimum. You should actually select the speed so as to limit the water temperature to <50C, so as not to damage the batteries in the process of heating them - probably you know that. 

We are using a PID loop to keep the temperature stable. We have full control of pump speed and heater current. 

Yes, 240W is not a lot of heat, but will have separate cooling loops for each box - the front one with 480W.


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## oudevolvo (Mar 10, 2015)

Thanks for the elaboration.
The heater I want to use in the end is the Defa 734.
It is 2000W and has an internal thermostat set at 40 degrees.
http://www.defa.com/file/9907654ac5a/GB DEFA SafeStart 721-734.pdf

Another option is the Calix PH2000L which also is 2000W and has a thermostat set at 50 degrees.
http://www.calix.se/files/29a4ed51bd360eb7ace4287652170a96.pdf/2015_Calix PH-heaterpdf

The one I have for testing is the 722 so with a thermostat of 80 degrees which I don't think is safe. If the control loop for some reason fails I will have a problem.


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## GoElectric (Nov 15, 2015)

Hi. That looks good, but 2000W seems like a lot. I have a 900W calx, but hope not to need that much power. My cabin heating is electric, so perhaps you are right if using your's for that as well. 

Yes, as far as failures go - you can program the Arduino to manage failures - ie: if flow-rate is not what it should be, temp, etc.... We will have a switch to detect water in the box (leaks)....

Let us know if you want to use our design for a manifold!

Jim


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## oudevolvo (Mar 10, 2015)

GoElectric said:


> Yes, as far as failures go - you can program the Arduino to manage failures


How do you cope with the fact that also Arduino can fail?
If Arduino crashes, I still want my pumps to run. I want a system that is intrinsically safe. Perhaps a parallel pull-up that sets the PWM to 100% if a certain Arduino output is nog high (ie offline). 


GoElectric said:


> Let us know if you want to use our design for a manifold!


Thanks! First I will need to get my batteries.


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## Kevin Sharpe (Jul 4, 2011)

What are you using for a pierburg pump mounting bracket?


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## oudevolvo (Mar 10, 2015)

Kevin Sharpe said:


> What are you using for a pierburg pump mounting bracket?




A second hand pump that I bought from a breaker came with a bracket for two pumps.
Probably will reuse that or create a similar one myself. I probably will use small mounting rubbers for the bracket to prevent vibration transfer to the chassis of the car.








It clamps around the pump with a rubber underneath. 
I think Tesla uses a similar approach for these kind of pumps.
They have a rubber around the pump.


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## Kevin Sharpe (Jul 4, 2011)

oudevolvo said:


> A second hand pump that I bought from a breaker came with a bracket for two pumps


Many thanks... any part numbers on that bracket or do you know what vehicle it came from?

For the benefit of anyone reading the thread, the pierburg pump was used on BMW, Audi, VW, and Porsche vehicles (see image for part numbers)


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## oudevolvo (Mar 10, 2015)

Unfortunately no part numbers on the bracket.
It came from a Fisker KARMA 2.0, so not very common.

And indeed, the CWA 50's are used in some more cars. Please be aware that there are two versions, 3 pin and 4 pin.
As far as I know VW and Audi use the 3 pin version and BMW and Fisker use the 4 pin version.
I don't know about Porsche.
Both versions are usable, but the wiring might be slightly different.
I use/prefer the 4 pin version.
The BMW part numbers for the connector are:
1 x 12527549033 Plastic Socket Housing
4 x 61138366245 Rubber sealing grommets
4 x 12527545858 Individual Socket Pins


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## Kevin Sharpe (Jul 4, 2011)

oudevolvo said:


> Unfortunately no part numbers on the bracket.
> It came from a Fisker KARMA 2.0, so not very common.


I don't think I'll bother looking for that part 



oudevolvo said:


> Please be aware that there are two versions, 3 pin and 4 pin.


Yeh, we still have plenty of the 4 pin pumps from the AZD auction.



oudevolvo said:


> The BMW part numbers for the connector are:
> 1 x 12527549033 Plastic Socket Housing
> 4 x 61138366245 Rubber sealing grommets
> 4 x 12527545858 Individual Socket Pins


Thanks for sharing that info... once I've located the OEM bracket part numbers I'll post them here.


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## oudevolvo (Mar 10, 2015)

Are you also using those small Buhler pumps? Believe those are from the AZD auction as well.

I use one of these for the controller+ DC/DC cooling circuit.








Anyway if anyone is interested, the part number of the connector for that pump is 3C0973203 (Volkswagen).


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## Kevin Sharpe (Jul 4, 2011)

oudevolvo said:


> Are you also using those small Buhler pumps?


No, we're using two of the Pierberg CWA50 initially... we only have two small radiators in the bus and really don't know at this point whether they will be adequate for the task... only one way to find out


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## winzeracer (Apr 3, 2012)

I really like these pumps and have used them, I made a model of the pump and printed a bracket. Here is my grabcad profile link Pump and Bracket with every file format you could want. Inluding .stl so that you could have it printed at 3dhubs or something if you do not have a printer.

https://grabcad.com/library/pierburg-cwa50-pump-and-bracket-1
or just the pump so you can make your own bracket
https://grabcad.com/library/pierburg-cwa50-pump-1

Also note that the rights or Pierburg itself seems to have been bought out, this looks to be the same pump, however I have not purchased one to verify that it has the same characteristics.

https://www.summitracing.com/int/parts/mof-pw534/overview/


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## Kevin Sharpe (Jul 4, 2011)

winzeracer said:


> Here is my grabcad profile link Pump and Bracket with every file format you could want.


That's really cool... thanks for sharing


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## Kevin Sharpe (Jul 4, 2011)

Great example of the power of sharing... bracket prototype printed in PETG by 3D Hubs


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## winzeracer (Apr 3, 2012)

Kevin Sharpe said:


> Great example of the power of sharing... bracket prototype printed in PETG by 3D Hubs


Awesome! Glad that file is getting some exercise


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## winzeracer (Apr 3, 2012)

Oh and the holes are for M5 button head or socket cap


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## Kevin Sharpe (Jul 4, 2011)

winzeracer said:


> Awesome! Glad that file is getting some exercise


Looking great and fits perfectly on pump... my sample had a couple minor printer artefacts which I mention just FYI, and the base/top is a tight fit which might benefit from a tiny adjustment (or tighter material tolerance)... either way it's a great design which I will use in my EV 

Do you have any thoughts on the final material choice? Nylon is readily available at low cost


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## winzeracer (Apr 3, 2012)

Looking good! I have made it with ABS and Carbon Fiber ABS hybrid. Nylon or ABS would be my recommendation, as there are some thin walls the Nylon can flex a bit instead of cracking. The Nylon could warp overtime, where the ABS is not as likely to warp. The carbonABS was too rigid and wanted to crack easily, the part would need to be optimized for a more rigid material.

Agreed the diameter could be loosened up by 0.010" - 0.020"

Kevin also check my grabcad for Tesla drive unit. I will also model up the gen 2 charger soon, building some of Damien's charger boards this week.


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## Hollie Maea (Dec 9, 2009)

Tomdb said:


> http://webpages.charter.net/n8nxf/EVTV%20Pierburg%20CWA-50%20Coolant%20Pump.pdf
> 
> Nope EVTV document states differently, plus it has been confirmed by others.
> signal 45-1100 HZ, duty cycle 13-85%


Did anyone get a copy of that PDF by any chance before the link died?


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## Tomdb (Jan 28, 2013)

Yes I do, and thats why I got a giant repository of most PDFs i find useful in a design. As the internet is an ever changing place.


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## Hollie Maea (Dec 9, 2009)

Thanks so much, Tom! I also downloaded it for the same reason but misplaced it since then.


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