Adding a Tacho to the diesel

[mollins]

I just spoke to a chap at Ringwood Spedometer (in Ringwood Melbourne, nice chap) and the W terminal is an unrectified tapping of the W phase stator coil. To make your own W terminal you can tap any phase (U, V, or W) before the rectifier. The W terminal is therefore an AC waveform. Im going to have a crack at this tonight and will inform you on the result.
Matt

any luck so far?

[smithy010]

I think hiho's problem will be a little simpler than mine...

I'm aiming to add a tacho input to the standard petrol clocks.
The issue i have here, is that i believe that the petrol tacho actually takes 4 pulses per rev... If the W terminal works, i will still have to find some piece of silicon which will multiply the pulse by 4, in order to get an accurate input for the petrol tacho..

I only thought of this issue recently... anyone got ideas?

[mollins]

If the W terminal works, i will still have to find some piece of silicon which will multiply the pulse by 4, in order to get an accurate input for the petrol tacho..

thats what the bit of gear that brackie orignally posted does.. takes the Alternating "W" signal and converts it to a tachometer signal for a 4 or 8 cylinder standard ignition tachometer. That one may be a bit expensive for you but it can also compensate for pulley sizes etc. **** smith or Jaycar may have similiar things for better prices... im having a look round for other options aswell..

[smithy010]

Should be able to do that with a PIC.
I'll work on it..

[smithy010]

Today, i managed to drive the tacho dial from a circuit based on a small microprocessor.
I think that's the hardest bit. Now all i have to do is put a tap in my alternator, measure the output, design the software, and bung it all together.

I'll keep you all posted.

[gldgti]

well done mate! keep us informed. i'll buy a kit off you when your finished.

[Edison]

I'm aiming to add a tacho input to the standard petrol clocks.

When you hit 88 miles an hour what happens to the clock?

[smithy010]

A v simple tach for a diesel engine is the original Tiny Tach - it counts the pulses of fuel in the feed pipe going to an injector.

And can be powered by a 9V dry cell for a year or so.

See http://www.tinytach.com/tinytach/diesel.php for more info.

Yes- But it won't drive the current petrol clocks, and it costs about $300 bucks.


Edison- What on earth does 88mph have to do with it? I don't plan on doing that speed in my diesel anyway....(nor should anyone else for that matter)..

[smithy010]

really?

I thought they were 200 US at least..

I must've been mistaken.
They still don't drive my petrol clocks.- I don't want to be reading a digital display!

[Edison]

Edison- What on earth does 88mph have to do with it? I don't plan on doing that speed in my diesel anyway....(nor should anyone else for that matter)..

twas a far too abstract piece of humour referring to the back to the futre movie, the tacho, feeding into the clock, time travel.... anyhow..