Waste Gate Actuator Control for Turbocharger Thermal Drift
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Solution Overview
Problem
In internal combustion engines with turbochargers, the repeated opening and closing of the waste gate valve leads to thermal expansion errors in the waste gate opening sensor, causing deviations in the actual opening degree and supercharging pressure control, resulting in unpleasant noise and overheating issues due to incorrect motor driving currents.
Innovation Solution
A control system with a control device that limits the operation amount of the waste gate actuator to prevent collisions with the open side stopper and adjust driving currents, using a position sensor to detect actual positions and calculate necessary operation amounts to maintain accurate control and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the waste gate valve is repeatedly opened and closed for long-term operation, then the valve can maintain functional operation, but temperature characteristics of the opening sensor and thermal expansion cause errors between detected and actual opening degrees
Solution Approach 1:
The control device uses feedback from the opening degree sensor to continuously monitor the waste gate valve position and compares it with the target position. When deviation is detected due to thermal expansion or sensor drift, the control device adjusts the actuator output to compensate and maintain accurate positioning despite long-term operation.
Solution Approach 2:
The system compensates for temperature characteristics by adjusting control parameters based on detected opening degree deviations. The control device modifies actuator drive signals dynamically to account for thermal expansion effects and sensor drift, maintaining measurement precision throughout long-term operation.
2Device complexity
If the waste gate valve opening degree is not accurately controlled, then the valve structure remains simple, but the supercharging pressure cannot be controlled to the desired value and collision noise occurs
Solution Approach 1:
The control device implements closed-loop control by continuously monitoring the actual opening degree via the sensor and adjusting the actuator drive signal to achieve the target opening degree. This feedback mechanism ensures reliable supercharging pressure control without requiring overly complex mechanical valve structures.
Solution Approach 2:
The system replaces complex mechanical positioning mechanisms with an electric actuator controlled by electronic feedback. The actuator precisely positions the waste gate valve based on control signals from the control device, achieving accurate supercharging pressure control through electronic rather than purely mechanical means.
3Ease of operation
If the waste gate actuator drives the valve to the fully open position without limitation, then the valve can achieve maximum opening, but the actuator may collide with the stopper and overheat due to excessive driving current
Solution Approach 1:
The control device calculates the required actuator operation amount based on the current opening degree and target opening degree before actuating the valve. By determining the precise operation amount in advance, the control device prevents the actuator from over-traveling and colliding with the stopper, eliminating the need for mechanical stoppers or current limiting circuits.
Solution Approach 2:
The control device continuously monitors the actual opening degree via the sensor and adjusts the actuator drive signal accordingly. When the valve approaches the target opening degree, the control device reduces or stops the drive signal, preventing excessive current flow and actuator overheating while achieving the desired valve opening.
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 system effectively prevents collision noise and overheating by accurately controlling the waste gate actuator's operation, ensuring the waste gate valve remains within safe operational limits and maintaining precise supercharging pressure control.
Implementation Method 1
a position sensor detecting actual position of the waste gate actuator
Data Source
AI summary
In a control system for an internal combustion engine, the waste gate actuator controls the opening and closing of a waste gate valve according to operation amount controlled by the control device, an actual position of the waste gate actuator detected by the position sensor for detecting the position of the waste gate actuator which correlates to the actual open position of a waste gate valve is inputted to the control device, the control device performs control for limiting the operation amount to stop to predetermined opening deviation in the direction toward open side from open side stopper position of the waste gate.