In some turbochargers, boost pressure is reduced by opening the wastegate valve. In a modern turbo charged car, the most common way for opening the wastegate is with a pneumatic actuator and an air control solenoid, controlled by the ECU. In the control systems studied the ECU utilizes a static feedforward and a PID controller, for the purpose of making the boost pressure follow its reference value. With no systematic method for tuning the controller, this can be time consuming, and a set of well defined experiments to determine PID parameters are desired.When test time in a real engine is limited or expensive, it is advantageousto work in a simulation environment before doing live tests. A model for thewastegate actuator and air control solenoid is developed in the thesis. This is used to simulate controller performance before any tests in a real car is performed.In the thesis a tuning method for the PID controller based on step responsesis proposed. The tuning method evaluated is the IMC-choice of controller fora second order system, and it has a single design parameter not given by theexperiments. The controller is shown to give desired behavior when the staticfeedforward is correct or has small error.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:liu-17207 |
| Date | January 2009 |
| Creators | Thomasson, Andreas |
| Publisher | Linköpings universitet, Institutionen för systemteknik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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