Paddle Shift System

[Der Krug]

Hello-
I am in the process of designed a sequential shift system using pneumatics for actuation of the gear box. I was wondering if there were other experienced teams who could provide insight on setup, and perhaps how they measure solenoid flow rates to get measurements on how many shifts a certain volume of air @ pressure would last. I am a freshman and this is basically a side project, that may or may not even end up on the car this year unless it can be pulled together by the end of March. So in essence, how many people run control units, and is it even worth the trouble- as opposed to just running a straight signal to trip the solenoid valve. Recommended parts etc...i've searched on this forum and didn't find what I wanted so I figured I'd sign up and make a post.

Thanks,

Steve

[Der Krug]

Hello-
I am in the process of designed a sequential shift system using pneumatics for actuation of the gear box. I was wondering if there were other experienced teams who could provide insight on setup, and perhaps how they measure solenoid flow rates to get measurements on how many shifts a certain volume of air @ pressure would last. I am a freshman and this is basically a side project, that may or may not even end up on the car this year unless it can be pulled together by the end of March. So in essence, how many people run control units, and is it even worth the trouble- as opposed to just running a straight signal to trip the solenoid valve. Recommended parts etc...i've searched on this forum and didn't find what I wanted so I figured I'd sign up and make a post.

Thanks,

Steve

[Some Guy]

Well, I'd want to know more about what you are trying to accomplish with this. Is it a case of "this will dramatically improve the performance of the car" or "we need to run an air shifter because everyone else does".

My experience is that you dont need to run a control module, but then it may not be much better than a regular cable shifter. At a minimum try and set it up so that the ECU can unload the engine on upshifts automatically.

Sizing all the component right can be tricky. I cant help you there unless I have more details about the car, motor, ECU, space, weight requirements etc...

[Der Krug]

Thanks for the reply.
It's a case of it will decrease shift time and allow the driver to focus more on driving and less on shifting- the idea behind all paddle systems.
We are using the Engine Lab ECU this year, new from last year's motec. I'm not sure if the EngineLab ECU is capable but I will ask around sometime this week.
Space is somewhat limited, it's hard to describe over the internet, but we are a little space cramped.

[Dash]

We did a push button air shifter last year. One of the team members made a circuit that sent a signal to the engine to kill it for 50ms on upshift. Worked like a charm. Also, to count shifts, a few years back a member just hooked up a new bottle to the actuator and shifted it until it wouldn't go anymore. If you could figure out the psi needed to get a shift, you could easily just count how many shifts you can get before it would run out. a I believe a 12 oz canister would be more than enough air for an endurance race.

[Some Guy]

The engine lab ECU is pretty slick, from what I remember of it you can program it to just about anything as it is more or less a blank slate, so you should be able to get it to do what you need.

Just make sure you don't run out of air/CO2. The only other thing I will add is that the force to shift the engine can be a lot more than you would expect.

[B Lewis @ PE Engine Management]

Most ECUs have this capability. For our new ECU you can set a digital input to kill the engine for a specific amount of time from about 10ms to 200ms. Somewhere around 30-100 seems to work best depending on how fast your hardware is.

[Der Krug]

Thanks for all the replies guys.

I will check with the engine team leader to investigate the engine kill on upshifts.
I had somebody help me with the my spreadsheet and calculated the Work to shift a lever 40 degrees.

Do most run with a clutch pneumatic cylinder too? I know you don't need to actually clutch on upshifts with our gearbox. I guess we'd have one 12oz tank running to 2 cylinders through 2 regulators.

[RenM]

for upshifts you will only need an ignition cut. for downshifting you will need the clutch. You can decide for yourself if the driver should actuate the clutch during downshifts or a cylinder.

[blister]

For Downshifts we used always a anti-hoping clutch form SuterRacing. A trained driver could downshift with it without using the clutch. For clucht actuation we used a brake master Cylinder and an aftermarket actuator for our engine. It worked very well.

We never used compressed gas to shift. A big Solenoid worked well for us for 4 Years. We knew that gas is probably the faster way to shift. But on the other hand there was no additional energy system needed on the car but petrol and 12V...

[Sam. B.]

blister do you know where you get your big solenoid? I'm just curious. Thanks!

[TMichaels]

I agree with blister: We also managed very reliable downshifts without opening the clutch by using an anti-hopping clutch and some timing tuning. There was not even the need for a trained driver to achieve clutchless downshifts.
We were using automatic up- and downshifting in Autocross and Endurance in 2008.

Regards,

Tobias

[RenM]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:
I agree with blister: We also managed very reliable downshifts without opening the clutch by using an anti-hopping clutch and some timing tuning.
</div></BLOCKQUOTE>

mmh I would advise to have a backup ready for clutch actuation because it doesnt seem to work with a honda cbr for example.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:
We were using automatic up- and downshifting in Autocross and Endurance in 2008.
</div></BLOCKQUOTE>

and nevertheless you were that fast? http://fsae.com/groupee_common/emoticons/icon_wink.gif

[blister]

THe solenoid was from Kendrion-electromagnetic. It was a prototype winding and weighed 1.7kg. The Actuator itself is undestroyable, just be ready to supply a lot of amperes (for a short time). You can use sensors for controlled ignition cuts. But in the end we used only the Motec tools for time delay and not sensors, i think you can set your ignition cut for all gears independently.

Anti Hoping Clutches are highly dependent on the rest of your drivetain. We tried two manufacturers and there was a big difference in their bite characteristics...I think these clutches were essential for our drivetrain