Valve Train Control via Cylinder Pressure Interference Signals
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Solution Overview
Problem
Existing valve train adjustment devices in internal combustion engines require complex design efforts for accurate position sensing, which complicates rapid and precise control, especially in continuously variable systems, and are prone to errors due to noise interference.
Innovation Solution
Evaluating cylinder pressure signals for interference patterns caused by valve opening and closing to determine the current setting of the valve train adjustment device, potentially using these signals as input variables for control or in conjunction with conventional position sensors to improve accuracy and enable diagnosis of errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is provided to accurately detect the current setting of the valve train adjustment device, then measurement precision is improved, but device complexity increases due to additional sensors and design effort
Solution Approach 1:
The system uses the cylinder pressure sensor's own measurements to detect valve train settings. The interference signals generated during normal engine operation are evaluated to determine valve positions, allowing the sensor to serve dual purposes without requiring additional position sensing equipment.
Solution Approach 2:
The interference signals, which were previously considered noise and harmful to accurate pressure measurement, are now utilized as useful information for detecting valve opening and closing events. By evaluating these interference patterns, the system extracts valuable position data without needing separate sensors.
2Measurement precision
If conventional position sensors are used for valve train adjustment control, then measurement precision is improved, but manufacturing precision requirements increase due to noise interference sensitivity
Solution Approach 1:
The interference signals caused by valve train operation are transformed from harmful noise into beneficial position indicators. By specifically evaluating the characteristic interference patterns during valve opening and closing, the system achieves accurate position detection without being affected by the same noise that would interfere with conventional sensors.
Solution Approach 2:
The system continuously monitors cylinder pressure signals and uses the detected interference patterns to provide feedback on actual valve positions. This feedback mechanism allows the control unit to verify and adjust valve train settings in real-time, compensating for any measurement uncertainties.
3Measurement precision
If additional position sensors are added to improve control accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The cylinder pressure sensor performs multiple functions: it measures cylinder pressure for combustion analysis and simultaneously detects valve train position through interference signal evaluation. This multi-functionality eliminates the need for separate position sensors while maintaining measurement precision.
Solution Approach 2:
The existing pressure sensing system serves its own calibration and measurement needs by using the interference signals it detects during normal operation to determine valve positions, making the system self-sufficient without external position sensing equipment.
Data Source
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AI summary
The invention relates to a method and to a control unit (24) for controlling an internal combustion engine (10) having at least one fuel injector (14) per cylinder (12), at least one camshaft (20) for actuating at least one inlet valve (16) and/or at least one outlet valve (18), wherein a valve-train adjusting device (21) is provided for controllably changing the actuating characteristic of at least one valve (16) which is actuated by means of the camshaft (20), optionally having a camshaft sensor (26) which supplies a camshaft signal (CAM) which is dependent on the camshaft angle, a crankshaft sensor (28) which supplies a crankshaft signal (CRK) which represents the crankshaft angle (CRA), and a control unit (24) for controlling the fuel injection and the valve-train adjusting device (21). In order to obtain information about the current setting of the valve-train adjusting device (21), at least one cylinder pressure signal (P) which is supplied by a cylinder pressure sensor (32) for measuring the pressure in an associated cylinder (12) is evaluated with regard to interference signals (S1), and the evaluation result is taken into consideration as an input variable in the control of the valve-train adjusting device (21).