View Single Post
Old 06-04-2011, 11:54 PM   #55
Dr_Bean OP
Joined: Jul 2004
Location: The Netherlands
Oddometer: 111
Originally Posted by ridewestKTM View Post
My system just tries to pump the WOT amount of fuel and when the bike was not WOT the pump just didn't cycle as far and everything is okey dokey
can you explain:
And how did you determine the pump was 'empty' , or how much pumpstroke you needed?
You can detect the pump-rod optically like I do, or magnetically (hall) which is difficult because of the coil fields,
or just detect the end-of-stroke by the current curve of the coil (second zero point in derivative), but you have to detect it someway!

So I do optically, and detect the empty-point (only). The ON time of the pump (sucking in the fuel) is actually fixed (sort of), but gets affected by some dynamic effects indeed. In reality that means that the on-time is a bit to small when it is running very slow, but that doesn't matter: If it doesn't get enough fuel, it will be empty sooner again an d the pump rate will go up...
The ON-time is to big if the pump is sucking in air: Normally that shouldn't happen, and if it happens: no problem... your bike will run out of fuel very soon after anyway; so this situation never lasts long

IF the optical detection fails completely (e.g. because the optics are to dirty) the pump will be activated about 1x per 2 seconds: A safety-run mode (the minimum pump frequency). Enough to bring you home with 60-80 km/h.

When the pump is full, and still running lower then 1x per 2 sec it will be activated anyway: In that case the pump-rod will be pulled to its end and some useless current will flow through the coil... heating it indeed: However, this cannot heat the pump because it is only happening 1x per 2 sec and the on-time is very short compared to this (Duty-cycle is very, very low)

The pump is really over-sized: When running at full speed (about 50% dutycycle) it delivers 70-to-90 liters of fuel per hour: That is enough to drive 300km/h using 1 liter on 4 km's : That is about 3x more then you will ever need, unless you are planning to take the adventure out to the black-rock desert for a testrun after fitting it with a couple of turbos

hence, in reality a maximum speed (=maximum consumption/time) the pump will only do about 20-30% dutycyle (on/off): In such case you also have lots of air-cooling and fuel-cooling in the pump.

I did take my own bike (with the prototype) into the sand-dunes of Morocco during rally, where the red-temperature light does go on: no problems
I sold my kit in Italy and Greece, where it does get warm: no problems so far.
But maybe not as warm as California or Nevada deserts (been there...): So DO take it out for a very hot testdrive and let me know!!!

IF EVER the kit would fail (useful for world-travelers!): you can very easily convert back to the original contact breakers!! So if you replace the contact breakers before they actually fail completely: save them, and take them as spare (including the 2 screws).
What do you need to do to revers it:
- Desolder (or cut if you don;t have anything) the black-coil-wire from PCB to pump-coil
- Desolder the blue-black wire to the PCB and form PCB-to-pump (this wire was cut for installing the kit)
- remove the kit and studs
- remount the contact breakers (note the ground wire whould be below one of the screws)
- connect the 2 ends of the blue-black wire together, and isolate them (you could use a fast shrink-fit)
- reconnect the coil wire to the breakers (original soldering)

ok: you need a soldering iron (the same holds for replacing the contact breakers): But in case of emergency you could do without: tying the wires together and put some tape over it.

Best way would be to detect both empty and full, but then I would need to mount something to detect the other end of the pumpstroke. I Tried to use the grove in the rod-end, but that is just too far away: Too tricky. I wanted to keep it as simple as possible: not adding more mechanical components

Dr_Bean screwed with this post 06-05-2011 at 08:24 AM
Dr_Bean is offline   Reply With Quote