Hydraulic Pump PCB Capacitance Sensing for Dry-Run Detection
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Solution Overview
Problem
Existing hydraulic pumps in motor vehicles lack a compact and efficient method to detect dry running, which can lead to pump damage and component failure due to inadequate lubrication or cooling.
Innovation Solution
A hydraulic pump with a capacitive sensor integrated on a printed circuit board in the wet chamber, utilizing electrodes to detect changes in capacitance caused by the dielectric properties of hydraulic fluid, allowing early detection of dry running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate capacitive sensor is added to detect dry running, then detection capability is improved, but device complexity and installation space increase
Solution Approach 1:
The capacitive sensor is merged with the printed circuit board that already exists in the wet chamber for controlling the drive motor. Two electrodes are formed directly on the circuit board as conductor tracks, eliminating the need for separate sensor components and reducing installation complexity while maintaining dry running detection capability
Solution Approach 2:
The printed circuit board serves dual functions: controlling the drive motor and detecting dry running conditions through the capacitive sensor electrodes formed on it. This multi-functionality reduces the overall device complexity by eliminating redundant components
2Loss of time
If electrodes are arranged in the upper half of the wet chamber, then early detection of dry running is achieved, but sensor placement constraints increase
Solution Approach 1:
The electrodes are positioned in the upper half of the wet chamber to enable preliminary detection of dry running conditions before they fully develop. This placement allows the system to detect capacitance changes early when the hydraulic fluid level drops, providing advance warning before complete dry running occurs
3Ease of manufacture
If conductor tracks are used as electrodes, then manufacturing simplicity is improved, but capacitance value may be insufficient
Solution Approach 1:
The conductor tracks are designed with meander or fork shapes that increase the effective surface area and length of the electrodes within the limited space on the printed circuit board. This dimensional optimization increases the capacitance value and detection sensitivity while maintaining the manufacturing simplicity of using standard PCB conductor tracks
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
Enables early detection of dry running with minimal additional space, preventing pump and component damage by triggering warnings before the pump completely runs dry.
Implementation Method 1
the evaluation unit can detect a change in the capacitance of a capacitor formed by the two electrodes
Implementation Method 2
The hydraulic fluid then serves as a dielectric, which has a higher relative permittivity than air
Data Source
AI summary
A hydraulic pump with a drive motor, a wet chamber, at least one printed circuit board which carries electronic or electrical components for controlling the drive motor and is located in the wet chamber, and an evaluation unit and at least two electrodes which are located on the printed circuit board in the wet chamber. The evaluation unit can detect a change in the capacitance of a capacitor formed by the two electrodes.