Boost Control Closed Loop Base Duty Cycle

Boost Control Closed Loop Base Duty Cycle

Only available is Boost Control Mode is set to Closed Loop.
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Due to there being more than one target value, the boost control solenoid needs to be pulsed at a different duty for different boost levels. This is achieved by giving the ECU a starting point for the different boost levels. The Closed Loop Base Duty table does this. In the above image, the duty is mapped over Boost Control Target Pressure so that as we change the Target the ECU knows which duty to use. See the Boost Control Target Pressure Table below as reference for the Tuning Tips below.



Tuning Notes

Based on this table, when using Setting 1 (Target is 10psi), the system will use 15% duty to reach this target boost amount. If this is not correct, the column for 10psi only must be adjusted until the boost pressure (read from the Controlled Parameter chosen in the Boost Control node) does reach 10psi. All other values in all other columns have no impact at all on the controller at this time.

When using Setting 2 (Target is 16psi), the system will use 38% duty to try to reach 16psi. If this is not correct, the column for 16psi only must be adjusted until the boost pressure (read from the Controlled Parameter chosen in the Boost Control Tab of the Function Page) does reach 16psi. All other values in all other columns have no impact at all on the controller at this time.

When using Setting 3 (Target varies between 18psi and 20psi), the system will use 46% duty until 5000 rpm to try to reach the 18psi target boost. From 5000 rpm it will then use 54% duty to try and reach 20psi boost. In this case, only the 18psi column should be adjusted with the engine running under 5000 rpm, and only the 20psi column should be adjusted with the engine running above 5000rpm.

NOTE: Changing the horizontal axis from Boost Control Target Pressure to simply Manifold Pressure does not give the system a way to know a starting point to get to the Target, as can be seen by the above description of how the system works. Also, setting the entire table to be one value means that the system will only reach a single target accurately and all other targets cannot be reached correctly. 

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