PLEASE HELP - Switch for Piezo Injector

Thread Starter

contiContiCONTI

Joined Oct 11, 2018
1
CALLING ALL CIRCUITS JUNKIES!

Good day all!

I am a mechanical engineering student and need help with some circuits ideas. My project requires me to model and construct an injector system for a one cylinder motorbike engine. We chose to use a piezo injector which, when a current passes through it, injects compressed air into the cylinder. To make this injection controlled, I require a type of ON/OFF switch that will close for around 10ms (letting current pass to the injector and therefore air into the cylinder), then open for about 60ms.

The problem is that we have multiple varying parameters (cylinder pressure and engine speed). Therefore, the opening and closing times will need to vary quite drastically from test to test. I need a switch which I can program with a MATLAB code that will stay open and closed for a specific amount of time depending on the coding. Without manual adjustment to the actual switch.

Please recommend any device or circuit idea that would allow me to do this.

Thank you!!!!

Christian.
 

ebeowulf17

Joined Aug 12, 2014
3,274
CALLING ALL CIRCUITS JUNKIES!

Good day all!

I am a mechanical engineering student and need help with some circuits ideas. My project requires me to model and construct an injector system for a one cylinder motorbike engine. We chose to use a piezo injector which, when a current passes through it, injects compressed air into the cylinder. To make this injection controlled, I require a type of ON/OFF switch that will close for around 10ms (letting current pass to the injector and therefore air into the cylinder), then open for about 60ms.

The problem is that we have multiple varying parameters (cylinder pressure and engine speed). Therefore, the opening and closing times will need to vary quite drastically from test to test. I need a switch which I can program with a MATLAB code that will stay open and closed for a specific amount of time depending on the coding. Without manual adjustment to the actual switch.

Please recommend any device or circuit idea that would allow me to do this.

Thank you!!!!

Christian.
What are the specs on the piezo injector, particularly the voltage and current requirements? Does it require DC, or oscillating AC? If it's AC, what frequency?

Is the motor stationary during testing? Can this switch be tethered to your MATLAB computer? Assuming the answer is yes, what output capabilities do you have on your MATLAB rig? 5, 10, 12V outputs? If not, you don't just need a "switch," you need a controller with brains to know when, and for how long, to run the injector.

If you're lucky, all you'll need is a transistor and a couple passive components to make a voltage controlled switch which can be driven by your MATLAB rig. But we need a lot more info before we'll know.
 
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