Cylinder Head Sensor Positioning for Combustion Measurement Accuracy
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Solution Overview
Problem
In multi-cylinder engines, the attachment positions of in-cylinder pressure sensors vary, leading to measurement deviations across cylinders due to interference with core prints and plugs in the cylinder head, affecting the accuracy of combustion state measurement.
Innovation Solution
The in-cylinder pressure sensors are strategically positioned relative to the intake ports and core prints, with the primary and secondary ports' positions interchanged between cylinders to align with the sensor's position, ensuring consistent measurement conditions by matching the intake flow direction with the sensor's location, thereby reducing measurement deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the in-cylinder pressure sensor is attached to avoid interference with the plug, then the measurement reliability is improved, but the attachment positions cannot be the same across cylinders leading to measurement deviation
Solution Approach 1:
The patent applies asymmetry by intentionally creating asymmetric attachment positions for in-cylinder pressure sensors across different cylinders. Specifically, sensors in odd-numbered cylinders are attached at positions offset in one direction from the cylinder center axis, while sensors in even-numbered cylinders are attached at positions offset in the opposite direction. This asymmetric arrangement allows all sensors to avoid interference with plugs located at standard positions while maintaining consistent measurement conditions relative to the intake flow direction in each cylinder.
Solution Approach 2:
The patent applies inversion by reversing the conventional approach of attaching sensors at the same position in all cylinders. Instead of maintaining identical attachment positions, the patent inverts the strategy by using alternating attachment positions for odd and even cylinders. This inversion resolves the conflict between avoiding plug interference and maintaining measurement consistency, as the alternating pattern ensures each sensor is positioned optimally relative to its cylinder's specific plug location and intake flow characteristics.
2Device complexity
If the primary port and secondary port are positioned in the same order in all cylinders, then the device complexity is reduced, but the measurement conditions for pressure sensors vary across cylinders
Solution Approach 1:
The patent applies local quality by customizing the port arrangement in each cylinder according to its specific position (odd or even) and the location of its in-cylinder pressure sensor. In odd-numbered cylinders, the primary port is positioned on one side of the cylinder center axis while the secondary port is on the other side. In even-numbered cylinders, this arrangement is reversed. This localized differentiation ensures that each cylinder's port configuration is optimized for its specific sensor attachment position, maintaining consistent measurement conditions across all cylinders despite the increased complexity.
Data Source
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AI summary
A cylinder head of a multi-cylinder engine is provided, the cylinder head including a plurality of ceiling parts for respective cylinders, and a water jacket. Each ceiling part is connected to an intake port including a primary port and a secondary port aligned in a cylinder-row direction, and is attached with an in-cylinder pressure sensor. A plug is attached to a hollow part of the cylinder head corresponding to a core print provided to a core of the water jacket, and is disposed at a position corresponding to a location between certain cylinders. The in-cylinder pressure sensor is attached at a position on an opposite side from the plug with respect to a cylinder center axis in the cylinder-row direction. Positions of the primary and secondary ports connected to each ceiling part are interchanged in the cylinder-row direction according to the position of the in-cylinder pressure sensor.