Technical > Wiring & Sensors
boost control
rob@vems.co.uk:
If you look at the UserGuide you'll see that there are two ways of fitting these Pierburg valves, one using a t-peice and the other using the valve as the T. There is a 3rd way, but its not recommended becuase of the lack of control if there is a solenoid failure, where the boost pressure is fed to the Common Open (CO) port, and the wastegate is connected to the Normally Closed (NC) port. While the boost is building the actuator "sees" no pressure until the desired boost pressure is reached and the NC port opens and bleeds pressure through the CO port.
Of course if the solenoid fails to open you get to sweep your engine up with a dustpan and brush... Which is why its not recommended;D
jadzwin:
I use the pierburg valve such way that by default (no current on valve) the actuator see full pressure,
and when there is a current, actuator see the atmospheric pressure (or even lower if the one of valve tubes is connected before turbocharger).
In my device that control boost, there is a 3D map that defines valve DC in fuction of RPM and MAP.
When the pressure is lower than required for about 0.2bar the valve DC is 100% making the westgate fully closed to help build the boost quicker. Editing this map we can perfectly control boost in RPM function. Moreover there can be several maps depending on gear and VSS based boost correction to prevent wheel spin.
This method give me very good result and it is quite safe.
Jadzwin
multiplex:
--- Quote from: rob@vems.co.uk on September 27, 2007, 08:49:13 am ---If you look at the UserGuide you'll see that there are two ways of fitting these Pierburg valves, one using a t-peice and the other using the valve as the T. There is a 3rd way, but its not recommended becuase of the lack of control if there is a solenoid failure, where the boost pressure is fed to the Common Open (CO) port, and the wastegate is connected to the Normally Closed (NC) port. While the boost is building the actuator "sees" no pressure until the desired boost pressure is reached and the NC port opens and bleeds pressure through the CO port.
Of course if the solenoid fails to open you get to sweep your engine up with a dustpan and brush... Which is why its not recommended;D
--- End quote ---
perhaps in my situation my boost is raising too quickly. so if i set the number to 210 the system can't react fast enough to keep the boost at 210. system being wastegate, turbo, etc.
i've read in other boost controller manuals (eboost2) that this is a typical, and they talk of having to set the number lower than your boost target.
maybe i'm missing something though ???
BenFenner:
--- Quote from: rob@vems.co.uk on September 27, 2007, 08:49:13 am ---Of course if the solenoid fails to open you get to sweep your engine up with a dustpan and brush... Which is why its not recommended;D
--- End quote ---
What about VEMS or MegaTune? Isn't there a setting you could use to cut fuel or spark once charge air pressure gets over a certain limit to prevent the dustpan/brush result?
rob@vems.co.uk:
Fuel cut above N kpa would do it.
But you do it at your own risk because its fail unsafe, rather than fail safe, if you get me ;D
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