Hydraulic Pump PCB Electrodes for Early 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 insufficient lubrication or cooling.
Innovation Solution
A hydraulic pump with a capacitive sensor integrated on the printed circuit board in the wet chamber, utilizing electrodes to detect changes in capacitance due to 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 by forming electrodes directly on the board. This integration eliminates the need for separate sensor components and reduces installation complexity while maintaining dry running detection capability. The electrodes are formed as conductor tracks or metallized surfaces on the same substrate that already houses control electronics.
Solution Approach 2:
The printed circuit board serves multiple functions: it provides structural support for control electronics, enables electrical connections, and simultaneously acts as the sensing element for dry running detection through its electrodes. This multi-functionality reduces the overall component count and simplifies the device architecture.
2Area of stationary object
If electrodes are placed in the lower region of the wet chamber, then space utilization is improved, but detection timing is delayed
Solution Approach 1:
The electrodes are positioned in the upper half of the wet chamber to enable preliminary detection of dry running conditions. By placing sensors where they can detect hydraulic fluid level changes earlier in the process, the system can trigger warnings before the pump completely runs dry, allowing preventive action to be taken.
3Ease of manufacture
If conductor tracks are used as electrodes, then manufacturing simplicity is improved, but capacitance value is reduced
Solution Approach 1:
The conductor tracks are configured in meander-shaped or fork-shaped patterns that extend across multiple dimensions of the printed circuit board surface. This dimensional expansion increases the effective electrode area and thus the capacitance value, while still using standard PCB fabrication techniques. The tracks may wrap around or extend between components to maximize sensing area without adding physical height.
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
Figure 1
Figure 2
AI summary
The invention relates to a hydraulic pump (10) with a drive motor (18), a wet chamber (20), at least one printed circuit board (24) which carries electronic or electrical components (26) for controlling the drive motor (18) and is located in the wet chamber (20), an evaluation unit (32) and at least two electrodes (30) which are located on the printed circuit board (24) in the wet chamber, wherein the evaluation unit (32) can detect a change in the capacitance of a capacitor formed by the two electrodes (30).