Wastegate Controller Boost Pressure Friction Compensation
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Solution Overview
Problem
The variability in friction of wastegates in exhaust turbine-type forced-induction devices leads to inconsistent response control, affecting the controllability of boost pressure, especially when the drive force is small, resulting in variations in the opening degree of the wastegate and impacting combustion quality in multi-bank engines.
Innovation Solution
A controller for the wastegate that adjusts the drive force based on the required boost pressure, setting it to a magnitude necessary to achieve the desired boost pressure, and using feedback control to maintain stability, even when the friction varies, ensuring consistent response and minimizing the impact of friction on drive control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the drive force of the wastegate is reduced to achieve lower boost pressure, then energy consumption is reduced, but the variation in friction greatly affects the response of control
Solution Approach 1:
The controller employs feedback control by monitoring the actual boost pressure and adjusting the wastegate drive force accordingly. The controller calculates the deviation between target and actual boost pressure, then modulates the drive force to correct any deviations, ensuring consistent control response regardless of friction variations.
Solution Approach 2:
The drive force applied to the wastegate is made dynamic rather than static. The controller continuously adjusts the drive force magnitude based on real-time operating conditions, including the required boost pressure and detected friction effects, allowing the system to adapt to varying friction conditions while maintaining control consistency.
2Reliability
If the drive force is increased to overcome friction variation, then control response consistency is improved, but the energy consumption increases
Solution Approach 1:
The controller applies partial action by providing just enough drive force to overcome friction variation and maintain control consistency, rather than continuously applying excessive drive force. The drive force is modulated to be sufficient only when needed to counteract friction effects, minimizing unnecessary energy consumption.
Solution Approach 2:
The controller changes the drive force parameter dynamically based on operating conditions. By adjusting the drive force magnitude according to the required boost pressure and detected friction effects, the system maintains control consistency while optimizing energy consumption across different operating ranges.
3Measurement precision
If the wastegate opening degree is precisely controlled to maintain boost pressure, then boost pressure control precision is improved, but the effect of friction variation on response becomes more significant
Solution Approach 1:
The controller acts as an intermediary between the boost pressure requirement and the wastegate actuation. It processes the boost pressure signal, calculates the appropriate drive force considering friction effects, and delivers the corrected control signal to the wastegate, thereby decoupling the precision requirement from the friction variation impact.
Solution Approach 2:
The controller replaces pure mechanical friction-based control with an electronically controlled system. By using electronic sensors and actuators with feedback control, the system achieves precise boost pressure control while compensating for mechanical friction variations through electronic signal processing rather than relying solely on mechanical force balance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The controller effectively limits the variation in response of the wastegate, maintaining consistent boost pressure control and reducing the impact of friction, thereby improving combustion stability across multiple banks in engines.
Implementation Method 1
The differential pressure of exhaust gas that results from the pressure loss when passing through the turbine wheel acts on the wastegate
Implementation Method 2
A wastegate is driven against the friction of sliding parts of the wastegate or against the friction of sliding parts of the drive mechanism
Data Source
AI summary
A wastegate is provided in an exhaust bypass passage that allows exhaust gas to bypass a turbine wheel of an exhaust turbine-type forced-induction device. A required boost pressure is set in accordance with a running state of an engine. A controller is configured to control a drive force of the wastegate to a magnitude that achieves the required boost pressure when the required boost pressure is higher than a preset pressure, and control the drive force to a magnitude that achieves a higher boost pressure than the required boost pressure when the required boost pressure is less than or equal to the preset pressure.