Engine Boost Pressure Control via Segmented Reference and Disturbance Rejection
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Solution Overview
Problem
Existing engine control systems face challenges in rapidly responding to boost pressure increases while minimizing engine pumping work, leading to suboptimal fuel efficiency and increased turbocharger lag.
Innovation Solution
Implementing a control system that combines a reference control system without integral feedback with a disturbance rejection control system that includes integral feedback, allowing for adjusted engine states and reduced error between desired and actual engine conditions, thereby improving response and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear control with integral feedback is applied to control boost pressure, then the boost pressure can be regulated, but the engine pumping work increases during transient operating conditions
Solution Approach 1:
The control system is segmented into two independent controllers: a reference controller that generates the desired boost pressure trajectory without integral feedback, and a disturbance rejection controller that handles deviations from the reference using integral feedback. This segmentation allows each controller to specialize in one function, preventing the integral term from causing excessive pumping work during transient conditions while still maintaining accurate boost pressure regulation.
Solution Approach 2:
The disturbance rejection controller uses integral feedback to eliminate steady-state errors between the actual and reference boost pressure. The integral term accumulates past errors and adjusts the control output accordingly, ensuring that boost pressure accurately follows the reference trajectory without requiring the reference controller itself to use integral action, thus avoiding the pumping work penalty.
2Speed
If boost pressure response is increased to reduce turbocharger lag, then the response speed improves, but engine pumping work increases
Solution Approach 1:
The reference controller generates a pre-calculated boost pressure trajectory that anticipates the desired response. By planning the reference path in advance based on driver input and operating conditions, the system achieves rapid boost response without requiring aggressive real-time control actions that would increase pumping work. The reference trajectory is optimized to balance response speed with energy efficiency.
Data Source
AI summary
Methods and systems for an engine controller are described. In one example, the engine controller includes a reference control system and a disturbance rejection control system. The engine controller avoids use of integral feedback in the reference control system, while permitting integral feedback in the disturbance rejection control system, to improve controller response without unduly increasing engine pumping work.