Technical Vapour recovery system

[allanhelen]

I didn't want to jump in the MS thread and take it off topic again but i have been reading the bits about the vapour recovery thing and it got me thinking

This basically terminates at the TB and the vapour is sucked in when the ECU decides it should be by opening a valve? under what conditions does it do this?

My question is that if this is designed to operate when there is negative pressure in the manifold right? So what happens when you have positive pressure in the manifold and TB ie Boost?

Does the control valve stayed closed on boost? can can it resist 1 bar of boost when it is designed to cope with vac?
if not what happens does the vapour get blown back into the tank presurising it more?
I am blowing air back into teh fuel tank rather than itno the engine?

 

[arc]

iirc the ECU only opens the valve under overrun conditons, with vacuum in the manifold and the throttle closed.

 

[allanhelen]

iirc the ECU only opens the valve under overrun conditons, with vacuum in the manifold and the throttle closed.

Ok so i would have vacuum there then,

What about the valve itself what sort is it? i presume that it is designed to withstand -1 bar rather than +1 bar?

Is it the same set up on the PGT?

 

[arc]

it's just an electronic solenoid, i don't reckon it'll care about the pressures - i also expect the canister will have a non return valve on it. But tbh, i suspect without properly venting the tank it will build pressure beyond 1bar anyway, so you've nothing to worry about. Even if it did pressurise the tank, the vent near the filler neck would fart and the pressure be equalised.

 

[allanhelen]

Cheers Arc, I was more worried about potentially loosing boost than venting the tank TBO

 

[arc]

if i've still got it, i'll stick an air hose on the valve next time i'm home and see how much pressure it takes before it leaks.

 

[Asteris]

Hydrocarbons stored at the EVAP canister, are meant to be directed to the engine for burning, so ECU does not open the valve at overrun conditions. From what i read, valve is opened at light throttle conditions, like while cruising.


http://www.fordscorpio.co.uk/evapmonitor.htm

 

[randomizered]

tada








Kristian

 

[Brooky]

well mine dont even work as i dont think its plugged in and a hose has snapped off

 

[allanhelen]

Kristian,

what are these condtions? what may be safe conditions for a normal ECU could be oh sh*t with an after market conversion

 

[randomizered]

Forgot about this post...oooppss


I don't know what the conditions would be tbh but if it was me I would:


only run the solenoid after engine warmup enrichment has stopped (approx 70 degrees)

only run with vacuum, no boost (even though cento's with MF2 and fooled MAP must be opening with boost, but i'd think it's not the best idea)

You could open on overun, there will be no issue with that, but it is wasted energy, hence why manufacturers don't do it. They will have a total fuel cut on overrun, as i do with my MS. Theres no point injecting any form of fuelling if the engine is doing the braking, and the only purpose of the whole recovery system is for car manufacturers to reduce unburnt hydrocarbons entering the atmosphere.

Therefore i would open it only when cruising, off boost, and up to temp.

You must also allow some sort of compensation for injector output when venting the vapour into the inlet, as it will enrich the mix. Wideband or even narrowband EGO adjustment should do the job well enough.

Saying that, i'd just not use it at all


Kristian

 

[rallycinq]

I placed my carbon cannister in the skip.

Cheers

D

 

[randomizered]

I placed my carbon cannister in the skip.

Cheers

D

:yeahthat:

it only serves one puropse, and lets face it, were not interested in that much with turbos, tuning et.