Hey guys i am the engine manager for my FSAE team and i am designing a telescoping intake manifold for the engine. Its been designed but the only issue is that the electrical team thats helping me do the electrical side of it so it can move up and down according to rpm's told me that the arduino microcontroller does not have a processor thats fast enough to keep up with the rpm changes. I sugested to use the proto area of the megasquirt since i am using a megasquirt to control the engine. He was kinda stumped on how to make a circuit to do so. I am asking here if any of you have any input or ideas on how to make it happen with the MS?
Thanks for the help in advanced

 

Any idea guys?

 

I don't think you can use an megasquirt for that, if you can someone please correct me, but I haven't found it yet. I've used an seperate module for that in the past, like this:

http://www.ignitech.cz/english/stps/stps.htm

Normally meant for an exhaust valve, but you could use it for a telescopic intake.
It's really simple and programmable, but it isn't lightning fast. It doesn't control a PID controlled servo or anything, just a 12V DC motor with a potentio type sensor. Worked good for me, but not as cool as this:

http://www.youtube.com/watch?v=EPcpmSdip_0

 

thats freaking awesome. I though maybe somehow a circuit could be made in the proto area but k. Does that module have for an input such as rpm signal? any idea how fast it is in comparison to something else to get an idea?

 

Yes, it has an RPM input which you can configure (amount of pulses / rev), and it's got a TPS sensor input if you want a 3d map. The TPS input is just a 0-5V signal so you can use it for pretty much anything you want. If you open up the link that's in my previous post you can download the software (when you open it up click 'Jazyk --> Anglicky for it to make sense). The speed depends on which motor you use to drive your intake. The device is meant to run motorbike exhaust 'servo's' which are generally pretty slow. You can use other 12V DC motors but it's rated at 3 amps peak max, you're limited to about 40 watts. The mazda 787B uses the same type of system and 'servo's' (DC motors with potentio type sensors) to drive it's variable intake, which takes 0,5 seconds to move from one end to the other. If you want a simple solution buy a linear actuator from (http://progressiveautomations.com/tu...47519ed1eea4a9) and hook it up to your ECU ouput using a DPDT relay, pretty fast, and easy to control, but it's just 2 positions, fully in and fully out.

These are just 2 ways that I know of, but there must be far better and faster options out there. I don't know about megasquirt though. Maybe you can use the idle solenoid valve output (which is a general PWM signal) to drive an actuator of some sort?

 

It wouldn't be too hard to throw together a PID controller for that...

I could do it in a day or two on MS3. MS2 might be a bit more difficult.

Ken

 

thank you very much, i have been looking at actuators.

we are going to get the ms3. Any way of being able to get one build for us or helping us out to build it?
Thanks

 

You mean the actual hardware? You probably don't want me to do it, I am not terribly great at fabrication.

For the PID stuff I have been thinking about creating a generic duty-based PID that lets you tie any duty based output to any ADC (voltage, 0-5v) based input with a PID loop. If you can create the mechanical and electronic systems for that I can make the code work.

Ken

 

Seems to me with a PID available as a 0-5V signal, you could use a standard model car/airplane/boat servo controller and servo.

 

K cool ill look into the hardware side with my electrical professor and ill let you know when its done for the code side.

 

Oh, and a servo controller is a very simple device:

http://www.aaroncake.net/circuits/servocon.asp

 

Thanks

 

did you ever get this to work? ive been looking for a 0-5v servo controller to use with my ms3x.

Aaron: would it be difficult to modify your circuit to have a 0-5v or pwm input to control it?