Hybrid fueling for PLC controlled hybrid

[matti]

Hi, I've been struggling to find the right fueling way for my hybrid thing for PLC (Programmable Logic Controller) controlled fueling.

Not sure what would be the best way to go for this PLC controlled fueling, but it gives me the possibility to use "fuel (gas) injection" like, direct acting solenoid valve or similar, I could control precisely the time that the valve is open for right amount of fuel to get to chamber or so.. do you think this would work ?

Now I use "manual" manometric fueling, I use Fairchild high precision regulator for it (Accuracy 0.1 psi), and it works ok, but not sure if manometric would be the best way for the automatic system and fast fueling cycle time.

Any ideas for what would be the best/most reliable fueling way for automatic/plc controlled fueling system), the mix is 4X Air/Propane and chamber is about 5 litres. I hope to get the cycle time/reload time to under 5 seconds

[jackssmirkingrevenge]

have you thought of syringe fuelling

Seriously, why not have a mechanically controlled piston which meters a correct amount of fuel, instead of having to worry about timing the thing?

Here's something I had been mulling over: http://www.spudfiles.com/spud-cannon-re ... 22379.html

[mark.f]

A literal fuel injector (automotive) with a regulated supply would work, but you would have to suss out the flow rate on your own. I actually have something like this in the pipeline for a combustion I want to finish up here pretty soon.

As far as fueling goes, though, unless you really really want electronically controlled injection, JSR's points hit home.

EDIT: keep in mind the flow rate of your injector will change as the pressure downstream rises. Inject fuel first (preferrably with a vent at the other side of the chamber).

[mobile chernobyl]

You could use the manometric fueling pretty easy with some simple C code. This was an earlier goal of mine but I never had enough time to implement it on a fully automated scale. You're going to want to have some sort of strong isolation valve given it's a hybrid, and I wouldn't recommend a Hydraulic solenoid valve - I was originally planning on using a motorized hydraulic needle valve, as these are metal-to-metal seating and can withstand 10Ksi pretty easily and for $50 usually. Short of that - either pneumatic actuated or solenoid actuated Poppit valves are obviously better, but would most likely require custom machining.

I don't know what make of PLC your using. I work with AB, Rockwell and Siemens equipment primarily at my (lame) job haha. If you had to use ladder logic that may make analog values a little funner to play with - but if you're just using a simple microcontroller like Arduino, PIC, Cypress PSOC or TI - You'll be able to work with much higher languages like C++ and JAVA.

[jackssmirkingrevenge]

*cough* cartridges *cough*

http://www.spudfiles.com/hybrid-cannons/topic19504.html

[POLAND_SPUD]

Wow awesome thread. I remember there was a similar thread a few years ago. Could you post pics of your setup ??

I think it's crucial to have some sort of feedback. I am not sure if it's the best idea to have something based on pressure only as it doesn't tell you anything about the mix inside the chamber so after the first shot you have to purge it. Wish there was a sensor like this one ->
http://www.pololu.com/catalog/product/1481
....but not limited to 1% only

[matti]

You could use the manometric fueling pretty easy with some simple C code. This was an earlier goal of mine but I never had enough time to implement it on a fully automated scale. You're going to want to have some sort of strong isolation valve given it's a hybrid, and I wouldn't recommend a Hydraulic solenoid valve - I was originally planning on using a motorized hydraulic needle valve, as these are metal-to-metal seating and can withstand 10Ksi pretty easily and for $50 usually. Short of that - either pneumatic actuated or solenoid actuated Poppit valves are obviously better, but would most likely require custom machining.

I don't know what make of PLC your using. I work with AB, Rockwell and Siemens equipment primarily at my (lame) job haha. If you had to use ladder logic that may make analog values a little funner to play with - but if you're just using a simple microcontroller like Arduino, PIC, Cypress PSOC or TI - You'll be able to work with much higher languages like C++ and JAVA.

Thanks, I have used a lot of time trying to find suitable valve that could be used for both fueling+isolation, because my goal is to get this thing working very reliably and with minimum amount of valves and regulators and other stuff.. my friend will help me with the PLC, he is engineer working with those things all the time, and I think its going to be something industrial "grade" system, maybe Siemens or similar.. those PLC things are little out of my knowledge, i still need to study little bit

Wow awesome thread. I remember there was a similar thread a few years ago. Could you post pics of your setup ??

I think it's crucial to have some sort of feedback. I am not sure if it's the best idea to have something based on pressure only as it doesn't tell you anything about the mix inside the chamber so after the first shot you have to purge it. Wish there was a sensor like this one ->
http://www.pololu.com/catalog/product/1481
....but not limited to 1% only

Thanks, I knew you would be interested with this project I try to get pics posted here in the next week or something, oh.. I should post the hybrid in the hybrid showcase, because its working and "ready" with manual operation, not automatic yet, but anyway ! ..There is also some very cool things in this hybrid, like that it has 90mm valve port and the chamber weights about 50 kilograms