Knock Sensor Mounting on Crankcase Boss for Single-Cylinder Engine
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Solution Overview
Problem
In single-cylinder internal combustion engines, knocking vibrations are detected less accurately when the knock sensor is mounted on the crankcase or cylinder head due to layout constraints and heat resistance issues, making it difficult to effectively detect knocking.
Innovation Solution
A single-cylinder internal combustion engine design featuring a sensor mounting boss on the crankcase or cylinder head, with the sensor positioned off-center relative to the axis of the bolt connecting the crankcase, cylinder block, and cylinder head, allowing for effective vibration detection of knocking vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the knock sensor is mounted on the cylinder block, then knocking detection accuracy is improved, but layout constraints and heat resistance issues prevent proper installation
Solution Approach 1:
The bolt serving as a fastener acts as an intermediary transmission path. Instead of mounting the sensor directly on the cylinder block (which is constrained by heat and layout), the sensor is mounted on the crankcase and uses the bolt to transmit vibrations from the cylinder block, thereby solving the mounting flexibility problem while maintaining detection accuracy.
Solution Approach 2:
The patent replaces direct mechanical mounting on the cylinder block with a vibration transmission mechanism through the bolt. This substitution allows the sensor to be positioned on the crankcase (where it's cooler and easier to access) while still detecting knocking vibrations transmitted through the bolt, thus resolving the heat resistance and layout constraints.
2Adaptability or versatility
If the knock sensor is mounted on the crankcase or cylinder head, then layout constraints are satisfied, but knocking detection accuracy deteriorates
Solution Approach 1:
The bolt serves as a vibration transmission intermediary that connects the crankcase (where the sensor is mounted) to the cylinder block (source of knocking vibrations). This allows the sensor to be positioned on the crankcase for layout flexibility while the bolt transmits the knocking vibrations accurately to the sensor.
3Measurement precision
If the knock sensor is mounted on the cylinder head, then proximity to combustion chamber is achieved, but vibration interference from non-knocking sources increases
Solution Approach 1:
The bolt acts as a selective vibration transmission path. It transmits knocking vibrations from the cylinder block to the sensor on the crankcase while isolating the sensor from direct exposure to other vibrations generated in the cylinder head region, thus reducing vibration interference from non-knocking sources.
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 configuration enables accurate detection of knocking vibrations, improves sensor reliability by reducing temperature issues, and optimizes space utilization while minimizing interference from rotational vibrations and external objects.
Implementation Method 1
When knocking takes place, the vibration resulting from the knocking propagates from the combustion chamber to the cylinder block, and then to the crankcase
Data Source
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AI summary
It is possible to detect knocking appropriately in a single-cylinder internal combustion engine in which a knock sensor is mounted to a part other than a cylinder block. A crankcase (11), a cylinder block (12), and a cylinder head (13) are connected by a bolt (60). A boss (40) for mounting a knock sensor (41) is formed on the crankcase (11). The center (40c) of the boss (40) is positioned on a side with respect to a cylinder axis (L1) in which the bolt (60) is provided, when viewed in an axial direction of the boss (40).