Fuel pump PWM control

[Wolf_Tm250]

Hi,
as I'd like to reduce the fuel pump noise and heat at idle/low load/rpm, I'd like to add a SSR between ecu and fuel pump.
Problem is that I have only one output left, the one I'm currently using as 101 "fuel pump" and, if I read correctly, using 124 / 138 (fuel pump control) or an Aux Table will lead you to loose the Delay/Priming option:
is that correct?
How to solve this?
Thanks

[Scott@FP]

Not sure about the priming, but don't use aux5-8, not high enough frequency, you need to use aux1-2 to get to 10K Hz, although some DC motors will run OK at 5K Hz. BTW manual is wrong, aux 3-4 top out at 5K Hz. If you don't have DBW use aux 1 or 2, swap some stuff around. You'll know when the frequency is near correct when it 'sounds' happier, wrong/too low freq will make them 'growl'.

For priming you could use the aux table and set up a timer, timer 1/2, closed throttle time as one axis and 0, 250 RPM.

[Wolf_Tm250]

Not sure about the priming, but don't use aux5-8, not high enough frequency, you need to use aux1-2 to get to 10K Hz, although some DC motors will run OK at 5K Hz. BTW manual is wrong, aux 3-4 top out at 5K Hz. If you don't have DBW use aux 1 or 2, swap some stuff around. You'll know when the frequency is near correct when it 'sounds' happier, wrong/too low freq will make them 'growl'.

For priming you could use the aux table and set up a timer, timer 1/2, closed throttle time as one axis and 0, 250 RPM.

Ah, yes, thanks!

[stevieturbo]

Not sure about the priming, but don't use aux5-8, not high enough frequency, you need to use aux1-2 to get to 10K Hz, although some DC motors will run OK at 5K Hz. BTW manual is wrong, aux 3-4 top out at 5K Hz. If you don't have DBW use aux 1 or 2, swap some stuff around. You'll know when the frequency is near correct when it 'sounds' happier, wrong/too low freq will make them 'growl'.

For priming you could use the aux table and set up a timer, timer 1/2, closed throttle time as one axis and 0, 250 RPM.

I've never seen an SSR rated for any higher than 1KHz though ?

To go to a proper frequency it will need a proper motor controller. I've seen guys use OEM fan controllers for such things though and some of these take a regular PWM input that would not need to be at a high frequency.

[Scott@FP]

Don't need a complex motor controller, its not a servomotor. Simple duty cycle speed control at the correct frequency for the motor, most likely between 2KHz and 10kHz.

Not a standard solid state relay, you use a setup similar to a dual half bridge such as this-

http://racegrade.com/ssd.html

Your PWM aux output DC% now controls motor speed. When your frequency is correct your usable DC% range is from around 10% DC to 100%. When it is incorrect for the motor it will be 'noisy' and have a much narrower control range.

Could probably whip one up easily out of an ignition IGBT that accepts 0v-5v gate signals but the SSD is pretty handy.

[stevieturbo]

That's only 10A per channel....that wont cover even a low output pump these days ?

GM Fan controller, Andrew B in the review has listed various plugs/terminals needed to complete this.

Obviously in the US, the controller can be bought very cheap second hand. If you search the net via part number etc, you can find various threads were people use this for pumps etc.

https://www.amazon.com/dp/B000EQP2AS/_e ... VG4TPRTUAY

On this side of the world, a lot of VW type cars also use a motor controller for their fans which could be used, although havent found pinouts etc for those and there seem to be more variants.

[Wolf_Tm250]

Not sure about the priming, but don't use aux5-8, not high enough frequency, you need to use aux1-2 to get to 10K Hz, although some DC motors will run OK at 5K Hz. BTW manual is wrong, aux 3-4 top out at 5K Hz. If you don't have DBW use aux 1 or 2, swap some stuff around. You'll know when the frequency is near correct when it 'sounds' happier, wrong/too low freq will make them 'growl'.

For priming you could use the aux table and set up a timer, timer 1/2, closed throttle time as one axis and 0, 250 RPM.

Sorry but, if i use the output aux table for the priming timer, how to control, then, the fuel pressure in closed loop?
Would need another aux table...

[Scott@FP]

Not sure about the priming, but don't use aux5-8, not high enough frequency, you need to use aux1-2 to get to 10K Hz, although some DC motors will run OK at 5K Hz. BTW manual is wrong, aux 3-4 top out at 5K Hz. If you don't have DBW use aux 1 or 2, swap some stuff around. You'll know when the frequency is near correct when it 'sounds' happier, wrong/too low freq will make them 'growl'.

For priming you could use the aux table and set up a timer, timer 1/2, closed throttle time as one axis and 0, 250 RPM.

Sorry but, if i use the output aux table for the priming timer, how to control, then, the fuel pressure in closed loop?
Would need another aux table...

The target pressure is determined by the scaling factor x the aux table value, the above 250 RPM axis row have your target pressure on at all times regardless of timer value. Probably several other ways to do it logically.

Also the best sensor to use would be a differential pressure sensor, with one port to the fuel rail and one port to the manifold so you maintain pressure across the injector tip. Fuel compatible differential pressure sensors aren't cheap. Its also possible to run it returnless style with a FP comp.

Not sure which SSD model I have, its a 4 channel, but if you gang all 4 channels together it will handle 40 A continuous.

[Wolf_Tm250]

The target pressure is determined by the scaling factor x the aux table value, the above 250 RPM axis row have your target pressure on at all times regardless of timer value. Probably several other ways to do it logically.

Ok, thanks!

Anyway I ended up leaving the idea as I forgot I would have even had a 2nd pump from tank to surge tank to run continuosly and pwmed...

[Hags86]

To get 20A out of a Dual Half Bridge you could gang the two channels together I would guess (can't see why not)

I've successfully done this using Subaru OEM Fuel Pump Controllers in my Toyota 86. It's a daily driver / track car and didn't want to hear fuel pumps whirring all day. The M150 package already contained the wiring and PWM control for the OEM in-tank pump. I've replaced the in-tank pump with a higher flow higher current unit and it's fine.

I added another Suburu Fuel Pump Controller to run the pump from the surge tank.

Specs are:
- Subaru Fuel Pump Controller (from a 2015 WRX or BRZ/FRS/86)
- 80Hz PWM
- 60% duty cycle is low speed
- 85% duty cycle is full speed
- Use a table with rpm as the lookup to drive fuel pump speed.

I'm driving both a DeatschWerks DW300C (in OEM tank) and a Walbro F90000267 (in surge tank) pump with these Fuel Pump Controllers for about 2 years no problems do they can handle the current fine.