Wastegate Control via Feedback and Dynamics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing control systems for wastegates in turbocharged internal combustion engines suffer from high construction dispersion, thermal drift, time drift, and hysteresis, leading to non-linear control maps and resulting in overshoots or undershoots in supercharging pressure, causing mechanical strain, noise, and oscillations.
Innovation Solution
A method that uses an electronic control unit to control the wastegate by combining an experimental control law with adaptive and closed-loop contributions, including low-pass filtering and PID regulators, to regulate the pneumatic actuator and manage the wastegate's opening and closing, ensuring precise control of supercharging pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pneumatic actuator with a contrast spring is used to control the wastegate, then the wastegate can be regulated based on pressure difference, but high construction dispersion, thermal drift, and time drift occur in the spring preload
Solution Approach 1:
The patent implements a closed-loop control system that continuously monitors the actual supercharging pressure and adjusts the wastegate position accordingly. The control unit receives feedback from a pressure sensor and dynamically adjusts the actuator control signal to maintain the desired supercharging pressure, compensating for spring preload variations and drift over time.
Solution Approach 2:
The control system dynamically adjusts the wastegate opening position based on changing operating conditions such as engine load, speed, and temperature. The control unit modifies control parameters in real-time to optimize supercharging pressure across different operating ranges, adapting to thermal drift and performance changes.
2Ease of operation
If a regulating solenoid valve is used to control the pneumatic actuator, then the wastegate opening can be regulated, but the control map becomes strongly non-linear due to hysteresis
Solution Approach 1:
The closed-loop control system continuously monitors the actual supercharging pressure and adjusts the wastegate position accordingly. The control unit receives feedback from a pressure sensor and dynamically adjusts the actuator control signal to maintain the desired supercharging pressure, compensating for spring preload variations and drift over time.
Solution Approach 2:
The control system transitions from a static control map to a dynamic control approach that adapts to changing operating conditions. The control unit adjusts wastegate positioning in real-time based on current pressure, temperature, and engine parameters, making the system behavior adaptable rather than fixed.
3Measurement precision
If the supercharging pressure is pursued closely using traditional control methods, then the objective pressure can be achieved, but high overshoots or undershoots occur causing oscillations
Solution Approach 1:
The control system anticipates pressure changes by adjusting the wastegate position before significant pressure deviations occur. The predictive control algorithm calculates the required wastegate opening to prevent overshoot or undershoot, counteracting pressure trends before they cause oscillations.
Solution Approach 2:
The control system applies partial control action by adjusting the wastegate to a position that achieves the desired pressure without excessive correction. Instead of fully opening or closing the wastegate, the system finds an optimal intermediate position that maintains pressure stability.
4Stability of the object's composition
If the integral term of the PID regulator is reduced to avoid oscillations, then pressure stability improves, but the pursuing of objective supercharging pressure becomes very slow
Solution Approach 1:
The control system dynamically adjusts PID parameters based on operating conditions and pressure error magnitude. The control unit increases the integral term when pressure deviation is large to accelerate response, then reduces it as pressure approaches the target to eliminate oscillations, optimizing both speed and stability.
Solution Approach 2:
The control system applies periodic adjustments to the wastegate position during the transient phase to rapidly approach the target pressure, then transitions to smaller, more frequent adjustments near the target to fine-tune and stabilize pressure without oscillation.
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
This approach provides a robust and cost-effective control method that reduces oscillations and turbo-lag, ensuring the wastegate operates within desired pressure ranges without overshooting, thus minimizing mechanical stress and noise.
Implementation Method 1
When the pressure difference between the two chambers is lower than an intervention threshold, the rod maintains the wastegate in a completely closed position, while when the pressure difference between the two chambers is higher than the intervention threshold, the contrast spring starts to compress under the bias of the flexible membrane, which is thus deformed, determining a movement of the rod
Implementation Method 2
A contrast spring, which is compressed between a wall of the shell and the flexible membrane 28, and which rests on the flexible membrane on the side opposite to the rod, is arranged in the first chamber
Implementation Method 3
a turbocharger provided with a turbine, which is arranged along an exhaust pipe to rotate at a high speed under the bias of the exhaust gases expelled by the engine, and with a supercharger, which is rotated by the turbine
Implementation Method 4
arranged along the air feeding pipe to compress the air aspirated by the engine
Implementation Method 5
By controlling the regulating solenoid valve, the second chamber can be connected to atmospheric pressure with a variable introduction gap, and thus the pressure difference between the two chambers can be regulated
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for controlling the wastegate (16) in a turbocharged internal combustion engine (1); the method contemplates the steps of: determining, during a design phase, a control law (CL) which provides an objective opening of a controlling actuator (35) of the wastegate (16) according to the supercharging pressure (P); determining an objective supercharging pressure (Pobj); measuring an actual supercharging pressure (P); determining a first open loop contribution (WGOL) of an objective position (WGobj) of a controlling actuator (35) of the wastegate (16) by means of the control law (CL) and according to the objective supercharging pressure (Pobj); determining a second closed loop contribution (WGCL1) of the objective position (WGobj) of the controlling actuator (35) of the wastegate (16); and calculating the objective position (WGobj) of the controlling actuator (35) of the wastegate (16) by adding the two contributions (WGOL,WGCL1).