Bypass Valve Fault Detection in Turbocharged Engine Air Control
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Solution Overview
Problem
Existing engine configurations fail to appropriately detect failures in valves that control air volume, particularly when the valves are stuck in an open or closed state, leading to inadequate combustion control.
Innovation Solution
The engine incorporates an intake pressure sensor and a control device that performs feedback control on the intake and exhaust bypass valves, determining abnormalities by monitoring the valve opening degrees and switching to a diffusion combustion mode if a failure is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature-based failure detection is used for the intake bypass valve, then closed-state failures can be detected, but open-state failures cannot be detected
Solution Approach 1:
The invention changes the detection parameter from temperature (which only detects closed-state failures) to valve opening degree (which detects both open and closed state failures). The control device monitors the actual valve opening degree against the instructed opening degree to comprehensively detect all failure modes of the intake bypass valve.
2Productivity
If feedback control is performed on both bypass valves, then air volume control is optimized, but system complexity increases
Solution Approach 1:
The invention segments the control approach by applying feedback control selectively: the intake bypass valve receives feedback control for optimized air volume management, while the exhaust bypass valve uses simpler control. This segmentation achieves good control performance without unnecessarily increasing overall system complexity.
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 early detection of valve abnormalities, preventing engine operation in a failed state and maintaining continuity of driving by switching to a backup combustion mode.
Implementation Method 1
an intake pressure sensor that detects a pressure of the intake manifold
Implementation Method 2
The turbocharger compresses air by using exhaust gas from the exhaust manifold
Data Source
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AI summary
In an engine (21), an exhaust bypass valve (V3) is disposed in an exhaust bypass channel (18) connecting an outlet of an exhaust manifold (44) and an exhaust outlet of a turbocharger (49) to each other. An intake bypass valve (V2) is disposed in an intake bypass channel (17) connecting an inlet of an intake manifold (67) and an inlet of the turbocharger (49). An intake pressure sensor (39) detects a pressure of the intake manifold (67). An engine control device (73) performs feedback control by outputting an instruction value of a valve opening degree to the intake bypass valve (V2) such that the pressure detected by the intake pressure sensor (39) approaches a set target pressure. If an instruction value indicating an upper limit or a lower limit of the valve opening degree of the intake bypass valve (V2) is continuously output for a predetermined time or more, the engine control device (73) determines that an abnormality occurs in at least one of the exhaust bypass valve (V3) and the intake bypass valve (V2).