Vehicle Washer Pump Level Detection via Current Monitoring
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Solution Overview
Problem
Current liquid level detection systems in vehicle windshield washer reservoirs are expensive and prone to leakage, with additional electrical connections increasing the risk of failure and complexity.
Innovation Solution
Utilizing the electric pump associated with the reservoir as a detection means by monitoring current consumption, which is directly proportional to the rotor speed, to determine the liquid level, allowing for alerting the user when the level falls below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional level sensors (float or electrode type) are used to detect liquid level, then accurate liquid level detection is achieved, but the cost increases and the risk of leakage and electrical failure increases
Solution Approach 1:
The pump is made to serve dual functions: liquid transfer and level detection. By monitoring the pump's current consumption, the system determines liquid level without requiring separate sensor components, thereby eliminating the leakage and electrical failure risks associated with traditional sensors while maintaining detection accuracy
Solution Approach 2:
The pump's own operational characteristics (current consumption variations) are utilized for level detection. The system leverages the pump's inherent response to liquid availability - when the pump runs dry, its current consumption changes, providing self-diagnostic capability without external sensors
2Measurement precision
If traditional level sensors are used, then liquid level can be detected, but the device complexity and number of electrical connections increase
Solution Approach 1:
The pump performs both liquid transfer and level detection functions, eliminating the need for separate sensor components and their associated electrical connections. The control unit repurposes existing pump control circuitry to monitor current consumption for level detection
Solution Approach 2:
The level detection functionality is merged with the pump's operational monitoring. The same electrical connection used to power the pump is also used to monitor its current consumption, thereby detecting liquid level without additional wiring
3Productivity
If the pump is positioned vertically (within 15° of normal) for optimal operation, then pump efficiency is maximized, but the pump cannot effectively detect liquid level when inclined at greater angles
Solution Approach 1:
The system monitors changes in the pump's current consumption parameter to detect liquid level. This approach works regardless of the pump's inclination angle because the electrical characteristics change when the pump runs dry, providing adaptability to various mounting positions while maintaining detection accuracy
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 method provides a cost-effective and reliable means to detect low liquid levels, optimizing alert timing and reducing the risk of electrical failures and leakage, while maintaining efficient operation even when the pump is inclined at angles greater than 15°.
Implementation Method 1
monitoring the current consumption of the pump, which is directly proportional to the speed of rotation of the electric motor of the pump
Data Source
Figure 1~2
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Figure 8~10
AI summary
Liquid reservoir (2, 3), in particular windshield washer fluid, for a vehicle wiper system, said reservoir comprising a body defining an internal storage volume of said liquid, and at least one electric pump (21, 21') having an inlet (21a, 21a') opening into said volume, said at least one pump having an elongated shape and comprising a longitudinal axis (A), characterized in that said longitudinal axis is intended to be inclined at an angle greater than 15° with respect to a normal (H) to the free surface of the liquid contained in the reservoir when the latter is filled with liquid and is in the mounted position in a vehicle.