Windscreen Wiper Protective Circuit Voltage Peak Mitigation
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Solution Overview
Problem
Existing protective circuits in screen wiper drives are inadequate in compensating increased voltage peaks, particularly at higher on-board voltages, which can lead to damage during vehicle screen wiping at increased speeds, and are not universally applicable across different vehicle-specific designs.
Innovation Solution
A protective circuit comprising a parallel configuration of a capacitor and a series connection of a diode and Zener diode, with specific voltage ratings, housed in a common unit to mitigate voltage peaks up to 70 V, ensuring compatibility with 12 V or 24 V nominal voltages and various automotive designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective circuit with a capacitor and varistor is used to reduce voltage peaks, then voltage peak reduction is achieved, but the circuit cannot compensate for increased voltage peaks at higher on-board voltages (level 2) without damage
Solution Approach 1:
The patent changes the protective circuit configuration from a simple capacitor-varistor parallel connection to a more complex circuit incorporating a diode, Zener diode, and capacitor with specific voltage ratings. The diode is selected with a reverse voltage of 400-1000V and the Zener diode with 33-50V reverse voltage, allowing the circuit to handle increased on-board voltages up to 60V and compensate voltage peaks up to 70V without damage.
2Reliability
If different vehicle-specific protective circuit designs are used for different automotive manufacturers, then voltage peak compensation can be optimized for each vehicle, but production costs increase
Solution Approach 1:
The patent creates a universal protective circuit design that can be applied across different vehicle-specific designs and automotive manufacturers. The circuit configuration with diode, Zener diode, and capacitor provides adequate voltage peak compensation for both level 1 (normal voltage) and level 2 (increased voltage up to 60V) operations, eliminating the need for manufacturer-specific custom designs and reducing production costs.
3Power
If the on-board power supply is operated at increased voltage (up to 27V or 60V) to enable starting during difficulties, then starting capability is improved, but voltage peaks increase causing damage to the protective circuit
Solution Approach 1:
The protective circuit is designed to provide beforehand cushioning against voltage peaks that occur during increased voltage operation. The diode and Zener diode are selected with reverse voltages that exceed the maximum expected voltage peaks, creating a safety margin that protects the screen wiper motor and other components from damage during jump start operations at increased on-board voltages.
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
The solution effectively compensates voltage peaks without damaging the protective circuit or other components, ensuring reliable operation across different vehicle-specific designs and increased on-board voltages, while maintaining economical production and assembly.
Implementation Method 1
A protective circuit in a screen wiper drive consists of a capacitor and a varistor parallel-connected thereto. Voltage peaks can in particular be reduced by means of such a protective circuit.
Implementation Method 2
A protective circuit comprising a parallel configuration of a capacitor and a series connection of a diode and Zener diode, with specific voltage ratings, housed in a common unit to mitigate voltage peaks up to 70 V
Data Source
AI summary
The invention relates to a protective circuit (10) in a screen wiper drive (1), consisting of a parallel circuit having two circuit elements (16, 17), wherein one circuit element (16) consists of a capacitor (18) and the other circuit element (17) consists of a series-connection of a diode (19) and a Zener diode (20), wherein the forward direction of the diode (19) and the Zener diode (20) is different and the Zener diode (20) inhibits in the direction of a plus pole.