hi!

I am currently doing my thesis on clutch automation on manual transmission systems. Can anybody give insights on how can i acquire the rpm of the transmission output shaft? currently my design uses a reed switch coupled to the speedometer cable. While the engine rpm is acquired using a freq/volt. converter circuit. Any insight will be appreciated.

 

With most recent vintage autos (and recent vintage for me is 1985+) there is some reliable electronic sensor already in place. This is used for many purposes in powertrain control and instrumentation. If you can't use that the reed switch is about state of the art. You might find someplace to mount a prox.switch. Accuracy is good if you average a bit. If you want better accuracy, I'd look at a mag sensor on the transfer gears or a gear on the output
shaft. By counting teeth and increasing the frequency you can get more resolution as drivetrains are turning pretty slowly in electronic terms. Or you can look at the ABS sensors as the drive wheels are geared to the output shaft, ignoring differential action.

Regards

cww

 

The reed switch is the right idea but may have some bounce at higher rpm. Try a Hall sensor for more accuracy. You will find a ton of cost effective pickups for rotational speed in the go kart industry. Simply search the web or ebay. They would include the readout as well.

You have chosen an interesting subject - I hope it leads you to efficiency of CVT transmissions.

[email protected]

 

Try http://www.sswhiteauto.com/Products/instru/pulse.htm
They sell pulse generators made to connect to the speedometer cable drive port on the transmission (assuming it has one). They also have other auto/truck gauges/sensors.

 

if you want a signal equivalent to RPM, nd you want it electricl you can tke it from the coil or from the injectors they change proportionaly to the motor speed (RPM)..

markk sigler