electronic rev limiter on mechanical pump

electronic rev limiter on mechanical pump - Printable Version

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electronic rev limiter on mechanical pump - mantahead - 04-07-2014

hi guys,
anyone any thoughts on a rev limiter on mechanical pump, something that works quick,
how could it be done?
say full fuel to 6500rpm, then bang limiter comes in.

RE: electronic rev limiter on mechanical pump - Duncansport - 04-07-2014

(04-07-2014, 07:27 AM)mantahead hi guys,
anyone any thoughts on a rev limiter on mechanical pump, something that works quick,
how could it be done?
say full fuel to 6500rpm, then bang limiter comes in.

I think the only way it would work is for it to by-pass or cut the fuel flow to the pump..?

RE: electronic rev limiter on mechanical pump - mantahead - 04-07-2014

i don't think it would be quick enough as there would still be fuel in the pump body.
it would have to pull the rack someway, i think.

RE: electronic rev limiter on mechanical pump - Duncansport - 04-07-2014

(04-07-2014, 09:12 AM)mantahead i don't think it would be quick enough as there would still be fuel in the pump body.
it would have to pull the rack someway, i think.

Now for the complicated forum answer.....

How about a 5/6 way block that could bypass all five or six injector lines back to the return via a solenoid. Say a block with some sort of spool valve..See this in cam phases solenoids a lot

RE: electronic rev limiter on mechanical pump - yankneck696 - 04-08-2014

The valve setup would have to withstand enormous pressures. If 1 failed, you would still have 1 cylinder firing at full strength & there goes your crank. How about using one of those "Clamp on the injector line" tachs, along with an Arduino & servo/PWM to directly work the ALDA, shutdown vacuum (Modulated), or governor? Restricting the fuel input can only cause harm by cavitation in the plungers. Cavitation can be very destructive.

Ed

RE: electronic rev limiter on mechanical pump - mach4 - 04-08-2014

One possible method that comes to mind would be a solenoid in line with the linkage that would physically increase the length of the linkage if it was pulling on the rack or physically decrease the length of the linkage if it was pushing the rack. If you used a sensor and a microcontroller you might even be able to use a PWM signal to maintain the set maximum rather than just cutting.

Variations on the theme would be to use the solenoid to change the radius of a connection on a bell-crank - might require a smaller solenoid.

You might also be able to use an exhaust brake type of rig on the intake to cut off the air supply. I have no idea whether this would do damage to the engine, but probably no more than over-revving it would do.

RE: electronic rev limiter on mechanical pump - Druk - 04-08-2014

(04-07-2014, 09:12 AM)mantahead i don't think it would be quick enough as there would still be fuel in the pump body.
it would have to pull the rack someway, i think.

Put an electric shut-off valve in parallel with the vacuum stop.

The pinhole is to allow vacuum to decay. It would likely need to be enlarged slightly and you still need some electronic method to control it.

.

RE: electronic rev limiter on mechanical pump - Tito - 04-08-2014

I was thinking of using a vacuum wastegate to pull the plunjers to max travel (I now use a cable attached to the throttle linkage, see my thread) hooked up to the kick-down switch.

Maybe you can do the same but in the opposite direction. And with a 3-way solenoid. Only problem is how to set max-rev with the solenoid opening point. Maybe you could try and see what a coil-style rpm sensor current is at max rpm (example: 25v AC) and hook something up that with the current 25v it switches on the solenoid. I dunno how acurate the current from the sensor is at those high rpm's.

I also think you'll need some thicker hoses and a vacuum accumulator to have enough vacuum all the time an quick response

But why would you want a electronical rev limiter while the original one works fine?