Discussion and questions related to the course Boost Control
Hello. I know this is not a completely new topic but I haven't seen anyone with the same exact issue.
I have a 350z pro plug in. We have tuned the open loop boost table up to 24 psi. I take the portion from the open loop map and put it into the closed loop base duty table. With PID set to zero I set target boost to 17 and go for a pull to see where the target is getting me. The boost control solenoid goes to 100% (wastegate pressure at 8psi) from the offset point to full load then down to 0% when i let off. There isn't any duty activity in the middle during the run.
I revert back to open loop and duty cycle does want it is supposed to throughout my entire boost range.
I put some P in as well and got the same thing.
I am using a Mac 3 port solenoid set at 7 psi startpoint at 30 hz. I attached a snapshot of a datalog that shows open loop runs then closed loop.
Any advice on how to resolve this issue? THanks.
At this point we haven't had the opportunity to set up closed loop boost control on the Haltech platform. As soon as we do though we will bring you a worked example which should be helpful.
I'm just wondering how you have the wastegate solenoid plumbed. It appears that in closed loop mode the Haltech is commanding 100% duty cycle but the boost remains at wastegate level of 8-10 psi approximately. If you have the wastegate plumbed up so that a duty cycle of 100% results in minimum boost then this would give the result you're seeing. The ECU will hold the wastegate at what it thinks is completely closed to allow fast boost building, but the boost never reaches the control range so the ECU doesn't go into closed loop control mode.
Alternatively if the active state of the DPO you're using is set to high then this will invert the output signal from the ECU. You wouldn't see this issue in open loop mode as the ECU will just provide the duty cycle programmed into the table.
That's my best guess based on the data you've provided.
Andre, thanks for the reply. I attached a picture of how my lines are set up. Its the top set up. However, in open loop 0% duty gives me wastegate pressure and goes up as I increase the duty cycle.
I look forward to a worked example. Thanks!
That's not my preferred method of connecting an external wastegate and 3 port solenoid, however it will work and the orientation will have 0% DC result in minimum boost and 100% will give maximum boost. I need to talk to Haltech today about another matter so I'll run it past one of my friends there.
Hey Andre did you get any feedback on my boost control setup? Thanks.