Linear actuator control with position sensing for turbo boost controller

Hi Im completely new to arduino and programming in general but hope to glean some useful knowledge from this forum. Id like to inquire to see if my idea is actually possible. I was thinking of a using a linear actuator to control turbo boost on my car, could I build a program that opens up a flap on the turbo to control boost by gear and such using arduino and a small linear actuator on the flap itself?

I was thinking of using a longer arm and mount the actuator itself away from heat. Also I would like to be able to do boost control by gear, would I be able to do this using arduino? If so, wheres the best place for me to start, and are there any helpful books or threads that I could focus on?

Please excuse my lack of knowledge, Im going to be scouring the internet and local library for more info on arduino but Id love to get some help from the community.

Thanks!

The actuator design will need to be determined from the forces and travel required, and the response speed (if that matters). There are other electrically operated exhaust baffles available so these might give you some idea of the sort of thing you’d be looking for.

If you want to be able to control boost according to the gear, you need a way to determine the current gear. Does your 'box already have a selected gear sensor output? They aren’t common. If you don’t have one, you might consider whether it would work to limit boost according to road speed (on the basis that you won’t be using the lower, presumably more fragile, gears once you have exceeded their red line, and if you’re under boost you will probably be in roughly the right gear for the road speed. Measuring road speed is quite a bit easier because most cars have wheel speed or transmission speed sensors and if not they’re usually not hard to add.

I was thinking of using this for the linear actuator: http://www.ebay.com/itm/XSCORPION-2-Heavy-Duty-Linear-Actuator-12-Volt-750LB-Static-w-Adjustable-Stroke-/390566439338?pt=LH_DefaultDomain_0&hash=item5aef92e9aa

It seems like it would be up to the task, 175lb of dynamic force available and its decently sized. You bring up a good point with regards to the boost by gear situation. To further clarify im actually going to be using a variable vane turbo, that is able to adjust its boost output as a function of the turbos shaft speed and the "hotside" a/r.

Could I then just moniter shaft speed, and mass air flow through a MAF or a MAP sensor, and build a map accordingly against throttle position values so that at given throttle input I would have a certain position on the vanes to help control boost?

sorry if this sounds confusing, what Id basically like to do is control the turbos variable vanes with the actuator and program it to where at half and full throttle the vanes slowly open as engine speed increases (as boost builds). And at no/light throttle fully open the vanes so that its not spooling for fuel economy. Id have some kind of secondary boost controller or solenoid that opens a flap to prevent any overboosting

Would this be possible with the arduino boards? Or am I in way over my head :sweat_smile:

Nothing you describe is impossible, although you should consider how much program space you have available for maps and whether it's actually practical for you to generate them. I don't know whether the algorithm you're describing is a sensible control strategy for your induction design, but it's the sort of thing that couple be implemented on an Arduino as long as you keep the size of any maps down to fit within the available program memory.

You would need to make sure that the Arduino is mechanically and electrically protected against shocks and spikes. Cars are quite hostile environments. Also consider the possible failure modes - if you have an electrical failure or a bug in your code, is there any conceivable output that results in damage to your engine or compromises the driver's control of the vehicle?

Finally, I'd have thought the most effective control algorithms for this type of turbo would be well known among people who work with them and you probably don't need to work them out for yourself - and there ought to be a standard implementation you can use too, whether that's an electronic control unit or simple pneumatic actuators.

Have you thought about using a vacuum signal to the wastegate actuator controlled by a solenoid like most digital/electronic boost controllers do?

How are you planning on using gear-based boost control (how do you intend to signal gear selection? microswitches close to the shifter housing?)

My concern with the linear actuator would be it's amperage draw, speed, and resistance to heat. the wastegate swing-valve/flapper door is right on the turbine housing, and it gets VERY hot.

I would think a linear actuator would possibly be too slow for fast performance use.