Technical > Wiring & Sensors

Output chanel Usage

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dnb:
No, I don't think the purge valve can't be energised all the time else you can collapse your fuel tank!!  (experience speaking here...)   Unless you have a very different sort of carbon can to me.

Can you have a look at  http://www.vems.hu/wiki/index.php?page=EvaporatorCanister and the associated pages so I can get an idea of if we are talking about the same sort of purge valve?

Thanks.

Sprocket:
I have researched the Rover Workshop manuals, and it is still unclear.

I think it is constantly open with engine temp above 70c and engine speed above idle.

I may have a contact that knows the chap involved with the software for the Rover MEMS, I'll see what i can find out if atall

Maybe some one could write up some code???? wouldnt be that difficult would it?

Extracts as follows

Purge valve

The purge valve is driven directly from by the ECM.
When the purge valve is opened it allows the EVAP
canister to vent into the engine inlet manifold. The
valve is opened by the ECM for varying periods
under specific engine conditions to avoid degrading
engine performance.


Evaporative emission canister

The evaporative emission (EVAP) canister is
situated beneath the LH inner wing valance, and
contains charcoal which absorbs and stores fuel
from the fuel tank when the engine is not running.
When the engine is running the vapour is purged
from the canister into the engine and burned.
The EVAP canister is purged when the EVAP
canister purge valve is opened. Manifold depression
draws fresh air into the canister through the
charcoal, which releases fuel vapour into the inlet
manifold.


Evaporative emission canister purge valve

The EVAP canister purge valve is operated by the
ECM. The valve remains closed until engine
temperature rises above 70°C. This is to maintain
engine tune and catalyst performance. If the valve
was to open with the engine cold or at idling speed,
the enriched mixture would delay catalyst light off
time and cause erratic idling. When the purge valve
opens, fuel vapour from the EVAP canister is drawn
along a pipe through the valve and into the inlet
manifold for combustion.


If I can get hold of a Can from a carb engine that uses a vacuum stat to operate a valve in the can, I think I'll use that :-\

Sprocket:
edit, wrong topic :-\

Sprocket:
Ok

The standard MEMS ECU controlled a main relay that switched on power to all the major components except the fuel pump relay, which is seperate, when it sees RPM at the Crank position sensor.

The question i am asking is, if i were to use a misc output and configure for on when rpm is 100 (minimum resalution)(i have no idea of crank rpm) to control the main relay to switch power on to the coil and injector. Will this be good enough?

I could always wire it in such a way that the main relay is on with ignition, but id prefer the control. I could at a push common this up with the fuel pump?

Whats the general consensus. Good idea, Bad Idea?

Also while im thinking about it, can you configure the output rpm trigger for less than the 100 rpm resalution, IE, use a figure of 0.5 to give 50rpm???????

rob@vems.co.uk:
A number of manufacturers seem to have that safety switch, I've used a misc output that is always on, or used the RPM actuator (Extras->WOT / RPM Actuators) set at 0rpm...

There are plenty of options... Experiment!

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