Shift Range Switcher Thermal Management via Dynamic Temperature Estimation
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Solution Overview
Problem
Conventional shift range switchers often unnecessarily prohibit motor operations due to overheating, as they rely solely on the number of shift range switching operations or fixed time intervals, leading to inefficient temperature estimation and potential unnecessary shutdowns of the electronic controller.
Innovation Solution
A shift range switcher with an electric control unit that calculates the estimated temperature of the motor and electronic control unit by accounting for heat generation and dissipation, using temperature adders and subtractors to accurately assess thermal limits and prevent overheating, thereby reducing unnecessary prohibitions of motor operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the initial learning process is prohibited for a predetermined period of time after being performed once, then the motor and electronic controller are protected from heat damage, but the system cannot respond to driver operations during the cooling period
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed prohibition period to a dynamic, adaptive prohibition period. The cooling period is no longer predetermined but is dynamically adjusted based on real-time temperature measurements of the motor and electronic controller. This allows the system to extend the prohibition period when temperatures are high and reduce it when temperatures drop faster than expected, optimizing both protection and operational responsiveness.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual temperatures of the motor and electronic controller during operation. This temperature feedback is used to dynamically adjust the prohibition period for the initial learning process, creating a closed-loop control system that adapts to real thermal conditions rather than relying on predetermined time intervals.
2Temperature
If the motor is prohibited from operation when a predetermined number of shift range switching operations is reached, then temperature increase is prevented, but operations are prohibited unnecessarily when the motor has cooled sufficiently
Solution Approach 1:
The patent replaces the mechanical counting-based prohibition system with a thermal measurement-based system. Instead of using a simple counter that prohibits operations after a predetermined number of switchings, the system now uses temperature sensors and control logic to prohibit operations only when actual temperature thresholds are exceeded, eliminating unnecessary prohibitions.
Solution Approach 2:
The patent changes the control parameter from a discrete count of operations to a continuous temperature measurement. This parameter change allows for more precise and accurate control of the prohibition logic, enabling the system to distinguish between cases where the motor is genuinely overheated and cases where it has cooled sufficiently between operations.
3Device complexity
If the counted number of shift range switching operations is used to estimate motor temperature, then the control logic is simple, but the temperature estimation is inaccurate and does not reflect actual cooling between operations
Solution Approach 1:
The patent replaces the simple counting mechanism with a temperature measurement system using thermal sensors. This substitution directly addresses the measurement precision problem by providing actual temperature data instead of inferred temperature based on operation counts, while the control logic remains relatively simple through direct temperature threshold comparisons.
Solution Approach 2:
The system uses the motor and electronic controller's own temperature measurements to determine when prohibition is necessary, eliminating the need for external estimation methods. The components self-report their thermal state, providing accurate real-time temperature information without requiring complex external monitoring systems.
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 allows the motor and electronic control unit to operate almost until the actual thermal limits are reached, minimizing unnecessary shutdowns and improving responsiveness to driver inputs while maintaining safety by accurately managing heat levels.
Implementation Method 1
The ECU temperature adder adds a first temperature value to the estimated temperature of the ECU. The first temperature value corresponds to the amount of heat generated in the ECU when the motor is energized.
Implementation Method 2
The ECU temperature subtractor subtracts a second temperature value from the estimated temperature of the ECU. The second temperature value corresponds to the amount of heat released from the ECU when the motor is de-energized.
Implementation Method 3
The heat controller prohibits or restricts operations of the ECU and the motor when the estimated temperature of the ECU reaches an allowable temperature limit of the ECU or when the estimated temperature of the motor reaches an allowable temperature limit of the motor.
Data Source
AI summary
A shift range switcher includes a motor for switching a shift range and a controller for energizing the motor. The controller estimates temperatures of the motor and controller. The controller adds to the estimated controller temperature a value corresponding to heat generation in the controller due to energization of the motor. The controller subtracts from the estimated controller temperature a value corresponding to heat release from the controller due to de-energization of the motor. The controller adds to the estimated motor temperature a value corresponding to heat generation in the motor due to the energization. The controller subtracts from the estimated motor temperature a value corresponding to heat release from the motor due to the de-energization. The controller prohibits or restricts operations of the controller and the motor when at least one of the controller and motor estimated temperatures reaches an allowable temperature limit.