Windshield Wiper Motor Control for Thermal Load Management
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Solution Overview
Problem
Windshield wiper motors experience excessive thermal loading due to high friction and wind loads, leading to reduced torque and potential shutdown, which necessitates oversized motors to maintain functionality, conflicting with the goal of compact and lightweight design.
Innovation Solution
A control device that adjusts the wiping frequency based on load thresholds and vehicle velocity, reducing energy input from wind loads and preventing thermal overload by dynamically adjusting the load threshold values and implementing interval operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-power windshield wiper motor is used to ensure sufficient torque for dry windshield operation, then the motor can maintain full power availability and reliability, but the motor size and weight increase
Solution Approach 1:
The patent applies dynamics by making the wiping frequency adjustable and adaptive rather than fixed. The control device dynamically modifies the operating parameters of the motor based on real-time conditions (traveling velocity, load thresholds) to optimize performance. This allows a smaller motor to deliver variable power output matching actual needs, resolving the contradiction between reliability and weight.
Solution Approach 2:
The patent changes the operating parameters of the motor system by adjusting wiping frequency based on traveling velocity and load conditions. The control device modifies frequency parameters dynamically, allowing the motor to operate efficiently across different power demands. This parameter adaptation enables a smaller motor to provide sufficient torque when needed while reducing weight compared to a continuously high-power motor.
2Reliability
If the wiping frequency is reduced to decrease energy input and thermal loading, then motor heating is reduced and reliability improves, but the windshield cleaning effectiveness decreases
Solution Approach 1:
The system dynamically adjusts wiping frequency based on traveling velocity and load conditions rather than using a fixed frequency. This dynamic adaptation allows the system to maintain high cleaning effectiveness at low velocities while reducing frequency at high velocities when thermal management is critical, thus resolving the contradiction between thermal stability and cleaning effectiveness.
Solution Approach 2:
The patent implements periodic wiping action with variable intervals controlled by the control device. By adjusting the periodicity of wiping cycles based on velocity and load thresholds, the system optimizes the balance between maintaining cleaning effectiveness and allowing thermal recovery periods, thus resolving the contradiction between productivity and thermal stability.
3Reliability
If the wiping frequency is reduced to compensate for wind load at high velocities, then energy input from wind loads is reduced and thermal overload is prevented, but the available wiping time decreases
Solution Approach 1:
The control device dynamically adjusts wiping frequency based on traveling velocity to optimize the balance between thermal protection and available wiping time. At high velocities where wind load causes thermal concerns, frequency is reduced to prevent overload. At lower velocities, full frequency is maintained to ensure adequate wiping time, thus resolving the contradiction between thermal protection and duration of action.
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 the use of smaller wiper motors without performance reduction, reducing weight and manufacturing costs while maintaining reliable operation across varying conditions.
Implementation Method 1
the energy input caused by the wind load in the drive unit can be reduced and thus failure of this drive unit caused by excessively high thermal loading is prevented
Data Source
AI summary
The invention relates to a control device (160) for a drive unit (120) of a vehicle windshield wiper system (100) comprising at least one wiper arm (140). The control device (160) is designed to determine a load quantity (L) of the drive unit (120) and to set the wiping frequency (WH) of the wiper arm (140) on the basis of the ratio of the load quantity (L) to at least one load threshold value (LS). Furthermore, the control device (160) is designed to set the wiping frequency (WH) depending on the current speed (v) of the vehicle.