Author Topic: Output chanel Usage  (Read 10979 times)

Offline Sprocket

  • Hero Member
  • *****
  • Posts: 867
  • BHP: 29
Output chanel Usage
« on: February 20, 2007, 10:52:18 pm »
There is the obvious output usage. I am looking for others to control an emissions purge valve on engine temp.

List of output i am looking for

Cooling fan

Fuel Pump

Tacho

Purge Valve

Possibly boost control.


Also on the subject of outputs. The heater for the WBO2 is controlled by VEMS directly. Can I wire this through the original relay and have VEMS control the relay. From the wiring diagrams I see a +ve 12v direct to the WBO2, is this grounded by the ECU, in which case i could use the relay in its place and then ground the heater throught the relay instead of the VEMS.

Offline rob@vems.co.uk

  • Hero Member
  • *****
  • Posts: 3115
  • BHP: 49
    • VEMS Forum
Re: Output chanel Usage
« Reply #1 on: February 21, 2007, 08:29:49 am »
The cooling fan & fuel pump relays are catered for in the software, you usually use the P259 output of your choice (its configurable in MegaTune).
The Tacho is available via FET or IGBT, I think dnb is going to sort that out for you.
Purge Valve is something that dnb wants too - we dont support its operation at the moment.
Boost control is again via FET.

The WBO2 heater must be controlled by the VEMS using a feedback system, the heater's state is constantly monitored to ensure that the signal from the WBO2 (the Nernst cell) is correct.  Just give the sensor a 5A fused 12V supply and have one less relay to go wrong in your car.

Offline dnb

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 837
  • BHP: 19
Re: Output chanel Usage
« Reply #2 on: February 21, 2007, 10:37:48 am »
Not quite true about the purge valve.  I had (before I took the whole car apart!) the purge can connected to one of the high current FET outputs of the VEMS.  (Misc Output A on EC18 connector IIRC) 

It was set to run an approximation to a purge cycle during a very narrow window of MAP, RPM and TPS just below cruise - so that every time you lifted off, the can was purged quite agressively for a few seconds.  We just need proper code to do this - the hardware is suitable, so you can wire it up now.

Offline Sprocket

  • Hero Member
  • *****
  • Posts: 867
  • BHP: 29
Re: Output chanel Usage
« Reply #3 on: February 21, 2007, 11:45:51 pm »
I was looking for just an out put switched on engine temp, im sure the purge valve is energised on all the time above a certain engine temp??? don't know for sure, i'm off to research that ???

Offline rob@vems.co.uk

  • Hero Member
  • *****
  • Posts: 3115
  • BHP: 49
    • VEMS Forum
Re: Output chanel Usage
« Reply #4 on: February 22, 2007, 08:36:19 am »
You have two triggers on temperature.
In MegaTune go to Extras->Fan/Water pump/Fuel Pump
You can use the Water pump output to control which ever type of driver you want to configure it with.

Offline dnb

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 837
  • BHP: 19
Re: Output chanel Usage
« Reply #5 on: February 22, 2007, 09:50:56 am »
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.

Offline Sprocket

  • Hero Member
  • *****
  • Posts: 867
  • BHP: 29
Re: Output chanel Usage
« Reply #6 on: February 22, 2007, 07:24:51 pm »
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 :-\
« Last Edit: February 22, 2007, 07:26:44 pm by Sprocket »

Offline Sprocket

  • Hero Member
  • *****
  • Posts: 867
  • BHP: 29
Re: Output chanel Usage
« Reply #7 on: March 15, 2007, 12:08:08 am »
edit, wrong topic :-\
« Last Edit: March 15, 2007, 12:14:42 am by Sprocket »

Offline Sprocket

  • Hero Member
  • *****
  • Posts: 867
  • BHP: 29
Re: Output chanel Usage
« Reply #8 on: March 15, 2007, 11:00:52 pm »
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???????

Offline rob@vems.co.uk

  • Hero Member
  • *****
  • Posts: 3115
  • BHP: 49
    • VEMS Forum
Re: Output chanel Usage
« Reply #9 on: March 15, 2007, 11:57:25 pm »
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!

Offline Sprocket

  • Hero Member
  • *****
  • Posts: 867
  • BHP: 29
Re: Output chanel Usage
« Reply #10 on: March 16, 2007, 01:48:08 am »
Getting my head round it now buddy ;D

Just finishing off the loom, its taken me all this week in the evenings so far :-\

Ta mucho :)

Offline Sprocket

  • Hero Member
  • *****
  • Posts: 867
  • BHP: 29
Re: Output chanel Usage
« Reply #11 on: March 27, 2007, 02:01:58 pm »