PREDATOR - valveless PDE build blog

[zono]

Hi guys,

its's good to hear, there is still interest on these items.

@ metiz: PDE means Pulse Detonation Engine - that are detonation pulses, no continuous run

...but no kidding, you are right, pulse rate can be increased from now 1.4Hz to about 5...10 Hz by using high pressure gas injection and high speed spolenoid valves (or piezo valves). That would be next development step.

[Growlzler]

Any further updates?

Growlzler...,

[zono]

Here ist some (poor) update. I purchased more suitable mosfets with lower R_ds(on) and lower Ugs, that helps for signal steepness at the ignition coil. But my solenoid valves still have 20ms trigger time. Piezo valves available only for low pressures and low flow rates.

Any ideas?

[Growlzler]

20 ms action time is a problem.

One idea is to apply a constant current through the coil - the idea is to decrease the mechanical actuation time when full current is applied by the Mosfet triggers. A little experimentation will be needed to reveal the appropriate setpoints.

Growlzler

[zono]

Hi Growlzler,
aah, as I understand, you propose to bias a direct current just below the trigger point of the coil? Is that right? This seems to be a very good idea...

thanks, I will try...if I got it right? Other ideas?

[Growlzler]

Hi Growlzler,
aah, as I understand, you propose to bias a direct current just below the trigger point of the coil? Is that right? This seems to be a very good idea...

thanks, I will try...if I got it right? Other ideas?

Hi Zono,

Yes, biasing the coil is the basic idea. Also applying a short supervoltage on the coil to get it moving is something you may want to consider. It won't smoke the coil if the duty cycle is low enough.

Growlzler