Vehicle HVAC Rotary Knob Control With Proximity-Activated Torque
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Solution Overview
Problem
Rotary control units in vehicle heating and air conditioning systems experience significant power losses due to the high current requirements of electric motors used to generate holding or counter-torque, affecting the overall energy balance.
Innovation Solution
A rotary control unit with a sensor system that detects hand proximity or touch to activate the electric motor only during intended adjustments, reducing power losses by switching off the motor during idle periods and varying torque based on rotation position, using a proximity sensor and position sensor to manage motor activation and torque levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor is continuously energized to generate holding or counter-torque, then the rotary control element maintains stable haptic properties and locking characteristics, but significant power losses occur due to high current requirements
Solution Approach 1:
The control circuit energizes the electric motor periodically based on sensor detection. When the sensor detects hand proximity or touch, the motor is activated to provide holding or counter-torque. When no interaction is detected, the motor is deactivated, reducing power consumption while maintaining haptic stability only when needed.
Solution Approach 2:
The sensor unit autonomously detects user interaction and triggers motor activation without continuous control input. The system serves itself by automatically activating the motor only when proximity or touch is detected, eliminating the need for continuous energization and reducing power losses.
2Loss of energy
If the electric motor is switched off during idle periods, then energy consumption is reduced, but the haptic properties and locking characteristics may be compromised
Solution Approach 1:
The sensor unit detects hand proximity or touch before the user actually interacts with the rotary control element. This preliminary detection allows the control circuit to activate the motor in advance, ensuring haptic properties are maintained when needed while keeping the motor off during truly idle periods.
Solution Approach 2:
The sensor provides continuous feedback about hand proximity or touch to the control circuit. Based on this feedback, the control circuit dynamically adjusts motor activation, ensuring haptic stability is maintained only when sensor signals indicate user interaction, thereby optimizing both energy consumption and haptic reliability.
3Manufacturing precision
If the holding torque is increased to improve locking characteristics, then the rotary control element provides better positioning accuracy, but the current requirement and power loss increase
Solution Approach 1:
The motor generates high holding torque only periodically when sensor detection indicates user interaction. During these brief periods, sufficient torque is provided for accurate positioning. During idle periods, the motor is off, eliminating continuous power loss while maintaining positioning accuracy when needed.
Solution Approach 2:
The control circuit dynamically adjusts the torque parameter based on sensor input. When proximity or touch is detected, the motor is activated with appropriate torque for accurate positioning. When no interaction is detected, torque is reduced to zero, optimizing the balance between positioning accuracy and power consumption.
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 approach minimizes energy consumption and reduces power losses by ensuring the electric motor is only active during actual user interactions, while allowing for adjustable torque and simulated locking noises to enhance user experience.
Implementation Method 1
the sensor unit is designed to detect a hand approaching the rotary control element or touching the rotary control element
Implementation Method 2
the electric motor is only supplied with current when an adjustment of the rotary control element is intended... in order to generate the torque in or against the direction of rotation (holding (or counter-torque) torque)
Implementation Method 3
the sensor unit can be provided with a position sensor for determining twisting of the drive shaft of the electric motor
Data Source
AI summary
The rotary control unit to which the invention relates, in particular nominal value rotary control unit for a vehicle heating system and in particular vehicle air conditioning system, is provided with a rotatable rotary control element (14), an electric motor (16) with a driveshaft (17) which is mechanically coupled to the rotary control element (14), an activation circuit (24) for supplying the electric motor (16) with power for the purpose of generating a holding moment in order to prevent undesired rotation of the rotary control element (14) and/or to build up a resistance as the rotary control element is rotated, and a sensor unit (22) for detecting a hand which is approaching the rotary control element (14) or is touching the rotary control element (14). The activation circuit (24) for supplying power to the electric motor (16) can be activated if the sensor unit (22) detects a hand which is approaching the rotary control element (14) or is touching the rotary control element (14).