View Single Post
Old 06-05-2011, 08:04 AM   #57
Beastly Adventurer
ridewestKTM's Avatar
Joined: Jun 2007
Location: now in Katy TX
Oddometer: 1,717
more discussion

Originally Posted by Dr_Bean View Post
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!!!

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

I'm sorry. I lost everything I wrote. I am going to be very short so not to loose what I write and I'm near out of time too.

My system has an approx 30% duty cycle. It pumps on a regular frequency. If the pump is full already it short strokes on the discharge. This way it always has a 30% heat load. Yours if set up right I assume it is, has an on period sufficent to cock the pump on the suck stroke. Then when fully discharged it fires again. Therefore only heating is when it fires and it only fires when disgorged. Better system then mine.
I still have some gen3 kits (coolest), gen 2s were about 40% duty cycle. But they will just sit here except special cases. You have the right thing.
My 950KTM makes me feel like a little kid again......because it's so tall!
ridewestKTM is offline   Reply With Quote