Closed loop fuel pump setup

[MikeyB571]

I'm sure others are now thinking of taking advantage of the new firmware which has closed loop fuel pump control.

So I wanted to do the same, am I right in thinking that I can ditch my fpr and install a fuel pump speed controller?

Has anyone used this before and if so what fuel pump controller have you used or h-bridge?

Thanks

[pavlo]

I have used a different strategy to do the same thing with an H bridge controller (before the closed loop strategy was available). I still used the FPR though and just varied the base duty to ensure the pump was running hard enough for the FPR to do some work. If you use the FPR you just need to ensure your integral doesn't wind up too much if you're using a control loop, or just use it open loop.

[MikeyB571]

Thanks Pavlo,

The only concern with that approach is that you might get a strange relative fuel measurement, maybe?
I want to see if the closed loop fuel pump control will work the way I am hoping it will and allow me to ditch the fpr and the return line, while having much quieter fuel pumps which aren't being worked quite as hard for normal driving.

Win win if I am reading it right

[stevieturbo]

Can the H Bridge thingy be bought separately ? What sort of current can they handle ?

What sort of input does it take ? 0-100% PWM ?

I'd like to control either my main pump, or additional pumps via PWM, just never been able to find a suitable controller

[pavlo]

http://www.ebay.co.uk/itm/High-AMP-60A- ... 1258109877

I put it in an aluminium box and screwed the FETS to the side to help heat dissipation, works a treat I run it at 10khz (output reflects input) and drive it 0-100% duty, I have used it with a regulated 5v source, 470ohm pullup resisitor and used a fuel output to pull it down, a 5v ignition output also works fine on an S6, not tried the TTL ignition out on S8

[MikeyB571]

Thanks again,

I had already ordered something similar: http://www.ebay.co.uk/itm/111008002912? ... 495wt_1161
Same thing I think and will drive my two pumps seperately. I'll do as you said and box it in a metal box and bolt the fets to the side for heat dissipation.

I am planning on using an Aux ouput rather than a fuel output as I don't have any to spare, I can't see any reason why this won't work as the H-Bridge should draw little current on the input.

I'll let you know if it works.

[pavlo]

An aux output will work, but you will need to convert it to 5v output, I used a 470ohm pullup to a 5v source but beware you will need to reverse the duty as it will be active low, so 80% duty will be 80% at 0v and 20% at high level. Just use all the duty backwards including your PID stuff.

[stevieturbo]

http://www.ebay.co.uk/itm/High-AMP-60A- ... 1258109877

I put it in an aluminium box and screwed the FETS to the side to help heat dissipation, works a treat I run it at 10khz (output reflects input) and drive it 0-100% duty, I have used it with a regulated 5v source, 470ohm pullup resisitor and used a fuel output to pull it down, a 5v ignition output also works fine on an S6, not tried the TTL ignition out on S8

Thanks Paul.

So I could use that unit to drive one or two 044's driven from one of my ecu 0-100% PWM's ?

ie, using these as booster pumps could just run them on demand only, as additional supply to a main pump running as normal ?

On-time duration wouldnt be particularly long.

[pavlo]

If I could I wouldn't bother using them as booster pumps, instead I would run them as primary pumps with varying duty. If you want to bring in a booster pump you can add an extra pump over a certain injector duty threshold. The point of using a controller is that you can do it seamlessly and the pumps are only working hard when they absolutely need to. But you should be able to do something to have all sorts of combinations.

[stevieturbo]

If I could I wouldn't bother using them as booster pumps, instead I would run them as primary pumps with varying duty. If you want to bring in a booster pump you can add an extra pump over a certain injector duty threshold. The point of using a controller is that you can do it seamlessly and the pumps are only working hard when they absolutely need to. But you should be able to do something to have all sorts of combinations.

It was more from the point of view that suddenly bringing another pump or pumps online via simple off/on might cause a brief spike in fuel pressure.

So the additional pump/s could be brought online at a slower rate

Unfortunately I dont have the option of an easy PWM for primary pump control on my non syvecs ecu so it would need to be applied to any additional pumps.