fuel pump controller
Discussion
I am looking at buying this one http://www.professional-products.com/secure/upload...
However having written them a no of emails I have yet to get a reply.
Your input appreciated as always
However having written them a no of emails I have yet to get a reply.
Your input appreciated as always
MarkWebb said:
I am looking at buying this one http://www.professional-products.com/secure/upload...
However having written them a no of emails I have yet to get a reply.
Your input appreciated as always
Interesting, that one does away with the regulator.However having written them a no of emails I have yet to get a reply.
Your input appreciated as always
I'd imagine that any pump that works with that would need to run comfortably at lower voltages for extended periods of time, during cruise for instance.
I would think not all pumps will be linear in their voltage versus pressure curve and may have trouble if the curve is not similarly linear.
On balance I think I would like to keep a regulator and just have a low / high rpm switch over, ie. upto 2500rpm low volume above 2500rpm high volume.
F.C. said:
I'd imagine that any pump that works with that would need to run comfortably at lower voltages for extended periods of time, during cruise for instance.
I've not found a std pump you can't run on a lower voltage, providing the driving system keeps the current ripple undercontrol (ie, probably uses a synchronous rectification type architecture) as that minimises the motors torque fluctuations and hence any vibration or noise. On my twin series 044s all i hear when the system is up to pressure but engine off is a very quiet "click clack" of the pumps internal one way ball valves oscillating slightly on their seats. Once any significant fuel flow occurs (ie, anything above about warm idle) the system is completely silent as my controller drivers the pumps with a PWM frequency above the human audible spectrum.Max_Torque said:
I've not found a std pump you can't run on a lower voltage, providing the driving system keeps the current ripple undercontrol (ie, probably uses a synchronous rectification type architecture) as that minimises the motors torque fluctuations and hence any vibration or noise. On my twin series 044s all i hear when the system is up to pressure but engine off is a very quiet "click clack" of the pumps internal one way ball valves oscillating slightly on their seats. Once any significant fuel flow occurs (ie, anything above about warm idle) the system is completely silent as my controller drivers the pumps with a PWM frequency above the human audible spectrum.
So using a digital signal to control pump duty?All these controllers will work using a Pulse Width Modulated (PWM) driving technique. This is because a linear control strategy would be un-acceptably lossy at these power levels.
Power = volts x current.
For a fuel pump: current = torque = fuel pressure and voltage = pump speed = fuel volume
So, generally, the pump current will be broadly constant with supply pressure, lets say at 10 amps.
At full speed, where battery voltage is applies directly to the pump, pump power is 12v x 10A = 120watts.
So, to run at half speed, a linear system would have to find a way of dissipating 60watts as heat somewhere in the system, which is simply not practicable.
By using a pwm driving architecture, the system creates a lower drive voltage with only two power semiconductor states (On & Off) so the losses are very much lower (in the order of a couple of watts, depending on the power devices used)
Power = volts x current.
For a fuel pump: current = torque = fuel pressure and voltage = pump speed = fuel volume
So, generally, the pump current will be broadly constant with supply pressure, lets say at 10 amps.
At full speed, where battery voltage is applies directly to the pump, pump power is 12v x 10A = 120watts.
So, to run at half speed, a linear system would have to find a way of dissipating 60watts as heat somewhere in the system, which is simply not practicable.
By using a pwm driving architecture, the system creates a lower drive voltage with only two power semiconductor states (On & Off) so the losses are very much lower (in the order of a couple of watts, depending on the power devices used)
Max_Torque said:
I wonder how many of those pump controllers they sell? I guess a few for LS (re)engined cars that have a returnless system as std these days?
Can`t be too many but I like the idea of not pumping 220l/h around the engine bay at full fuel pump speed. Changing diameters on different connections always changes the flow rate and fuel pressure and with it the boiling point of the fuel.macgtech said:
So presumably this reduces flow to a manageable level without going low enough to adversely affect pressure?
The fuel rail pressure is maintained at any given engine load by varying the fuel pump speed. A pressure sensor in the fuel line is connected to the fuel pump controller which then controls fuel pump speed.It`s very simple and effective, by varying the fuel pump speed you supply the fuel rail constantly but don`t circulate excess fuel which simply heats up.
Pretty much all OEM vehicles moved to "returnless" fuel systems about 10/15 years ago, when the tightening emissions regulations mean't that evaporative emissions from the fuel system became critical. By having a pump that controls rail pressure to a target, without a conventional regulator or spill back mean't much reduced bulk fuel upheat, and as a result, significant reduction in the vapour pressure in the tank and hence the volume of hydrocarbon vapour that the activated carbon canister had to catch!
SchimmS said:
The fuel rail pressure is maintained at any given engine load by varying the fuel pump speed. A pressure sensor in the fuel line is connected to the fuel pump controller which then controls fuel pump speed.
It`s very simple and effective, by varying the fuel pump speed you supply the fuel rail constantly but don`t circulate excess fuel which simply heats up.
I was wondering exactly that - whether or not it had a pressure sensor as part of a feedback loop or if it needed controlling some other way.It`s very simple and effective, by varying the fuel pump speed you supply the fuel rail constantly but don`t circulate excess fuel which simply heats up.
macgtech said:
SchimmS said:
The fuel rail pressure is maintained at any given engine load by varying the fuel pump speed. A pressure sensor in the fuel line is connected to the fuel pump controller which then controls fuel pump speed.
It`s very simple and effective, by varying the fuel pump speed you supply the fuel rail constantly but don`t circulate excess fuel which simply heats up.
I was wondering exactly that - whether or not it had a pressure sensor as part of a feedback loop or if it needed controlling some other way.It`s very simple and effective, by varying the fuel pump speed you supply the fuel rail constantly but don`t circulate excess fuel which simply heats up.
Sensor sits on fuel rail, and has a "T" off to measure plenum air pressure, that way, the engine control unit can control injector differential pressure:
or
F.C. said:
I take it the carbon canister is in the vent line from the tank(s)?
what sort of size are these? weight wise what are we talking, 1KG carbon?
Depends of the application and the emission std to which the car is designed. They can be physically quite large, say 3L volume and approx 2kg with valve and pipes etcwhat sort of size are these? weight wise what are we talking, 1KG carbon?
SchimmS said:
How much do those^^^ systems cost btw? They both look engineered down to a price rather than properly designed.........Gassing Station | Ultima | Top of Page | What's New | My Stuff