Engine Dipstick Natural Frequency Optimization
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Solution Overview
Problem
Engine dipsticks are prone to bending and vibration due to their material properties and elongated shape, leading to noise, vibration, and harshness (NVH) issues when installed through engine casings with simple through holes, causing resonance and contact with interior walls, resulting in unwanted noise during engine operation.
Innovation Solution
The engine casing and dipstick are adapted to ensure the lowest natural frequency of the dipstick's free end is above the highest operational frequency of the engine by configuring the shape, material, and mass distribution of both components, with projections on the casing and dipstick to prevent resonance and contact with interior walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the dipstick is made with simple through holes in the engine casing for easy installation, then the ease of manufacture is improved, but the dipstick becomes prone to bending and vibration causing NVH issues
Solution Approach 1:
The patent modifies the geometric parameters of the dipstick, specifically the length of the free end and the cross-sectional dimensions, to change the natural frequency of the dipstick. By adjusting these parameters, the natural frequency is shifted away from the engine's operational frequency range, thereby eliminating resonance and reducing NVH issues while maintaining the simple through-hole installation structure.
2Measurement precision
If the dipstick extends freely into the oil pan to measure oil level, then the measurement function is improved, but the free end contacts the interior wall causing harsh rattling noise
Solution Approach 1:
The patent changes the length parameter of the dipstick's free end to a specific optimized value. This parameter adjustment ensures that the natural frequency of the free end does not coincide with engine operational frequencies, preventing resonance-induced contact with the oil pan interior wall and eliminating rattling noise while preserving the oil level measurement function.
3Adaptability or versatility
If the dipstick has an elongated shape to reach the oil pan, then the functionality is improved, but the dipstick becomes prone to bending and vibration
Solution Approach 1:
The patent optimizes the geometric parameters of the elongated dipstick, including its length, cross-sectional area, and wall thickness, to adjust the natural frequency. By carefully selecting these parameters, the dipstick maintains its elongated shape for reaching the oil pan while ensuring its natural frequency lies outside the engine's operational frequency range, thereby preventing resonance and reducing vibration.
4Ease of operation
If the dipstick material is flexible enough to be installed through engine casing, then the ease of installation is improved, but the dipstick resonates during engine operation
Solution Approach 1:
The patent selects dipstick material and dimensional parameters such that the natural frequency of the installed dipstick falls outside the engine's operational frequency spectrum. This parameter optimization allows the dipstick to be sufficiently flexible for easy installation through the engine casing while preventing resonance during engine operation, thereby ensuring reliable performance without NVH issues.
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 effectively prevents the dipstick from resonating and contacting interior walls, thereby reducing NVH issues and ensuring quiet engine operation by ensuring the dipstick's natural frequency exceeds the engine's operational frequencies.
Implementation Method 1
at least one of the dipstick and the engine casing is adapted to ensure that the lowest natural frequency of the free end of the dipstick is above the highest operational frequency of the engine
Data Source
Figure 1a
Figure 1b
AI summary
An engine (101) comprising an engine casing (103) and a dipstick (105), the dipstick (105) having a free end (121) that extends into the engine casing (103) when the dipstick (105) is installed to the engine casing (103), wherein the lowest natural frequency of the free end (121) of the dipstick (105) is above the highest operational frequency of the engine (101).