Actuation systems for automotive boost control incorporate a vacuum tank and PWM controlled vacuum valves to increase the boosting system flexibility. Physical models for the actuator system are constructed using measurement data from a dynamometer with an engine having a two stage turbo system. The actuator model is integrated in a complete Mean Value Engine Model and a boost pressure controller is constructed. Based on the actuator model a nonlinear compensator, capable of rejecting disturbances from system voltage, is developed. A boost pressure controller is developed for the vacuum actuator and engine, using IMC. The complete controller is evaluated in an engine test cell where its performance is quantified and system voltage disturbance rejection is demonstrated.

a b s t r a c tAn actuation system for flexible control of an advanced turbocharging system is studied. It incorporates a vacuum pump and tank that are connected to pulse width modulation controlled vacuum valves. A methodology for modeling the entire boost pressure actuation system is developed. Emphasis is placed on developing component models that are easily identified from measured data, without the need for expensive measurements.The models have physical interpretations that enable handling of varying surrounding conditions.The component models and integrated system are evaluated on a two stage series sequential turbo system with three actuators having different characteristics.Several applications of the developed system model are presented, including a nonlinear compensator for voltage disturbance rejection where the performance of the compensator is demonstrated on an engine in a test cell. The applicability of the complete system model for control and diagnosis of the vacuum system is also discussed.

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