Turbocharger Boost Control via Feed-Forward Turbine Flow Calculation
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Solution Overview
Problem
Existing turbocharger control systems face challenges in accurately providing the desired boost pressure to internal combustion engines due to variations in exhaust gas conditions, leading to inefficiencies and the need for large look-up tables or time-lagged closed-loop feedback systems.
Innovation Solution
A method that calculates the compressor power and turbine flow based on a boost pressure command, using a feed-forward algorithm to adjust the wastegate and variable geometry turbine positions to achieve the desired boost pressure, with optional closed-loop corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop feedback systems are used to control turbocharger boost pressure, then accuracy is improved, but time lag increases
Solution Approach 1:
The patent applies feed-forward control by calculating the required turbine flow and wastegate position based on predicted exhaust gas conditions and desired boost pressure before the actual condition changes occur. This preliminary calculation allows the system to anticipate needed adjustments rather than reacting after deviations occur, eliminating time lag while maintaining accuracy.
2Measurement precision
If large look-up tables are used for turbocharger control, then accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical look-up tables with a mathematical model-based calculation system. Instead of storing pre-computed values in large tables, the system uses real-time calculations based on exhaust gas conditions, desired boost pressure, and turbocharger characteristics to determine the optimal wastegate position and turbine flow, significantly reducing storage requirements and system complexity.
3Speed
If feed-forward control is used to adjust turbocharger operation, then response speed is improved, but measurement precision may worsen
Solution Approach 1:
The patent combines feed-forward control with feedback mechanisms by continuously monitoring actual exhaust gas conditions and comparing them with predicted values. This feedback loop allows the system to correct any deviations from the desired boost pressure while maintaining the fast response speed of feed-forward control, achieving both rapid response and high precision.
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 allows for immediate and accurate adjustment of turbocharger operation to maintain the desired boost pressure, reducing the need for extensive recalibration and minimizing time lag, thereby enhancing engine performance and efficiency across varying conditions.
Implementation Method 1
One or more turbochargers are driven by exhaust gas from the engine. The energy captured from the exhaust gas is used to pressurize intake gases
Implementation Method 2
The energy captured from the exhaust gas is used to pressurize intake gases used in combustion within the engine
Data Source
AI summary
A method for controlling a turbocharger is provided. The turbocharger has a turbine operatively connected to an exhaust of an internal combustion engine, and a compressor operatively connected to an intake of the engine. The method includes determining a boost pressure command for the compressor. The boost pressure command is configured to provide sufficient combustion reactant for the engine. The method includes calculating a compressor power from the determined boost pressure command, and calculating a turbine flow from the calculated compressor power. The method commands the turbocharger to operate at the calculated turbine flow.