Shift Range Control Using Estimated ECU Temperature
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Solution Overview
Problem
Existing shift range control devices often prohibit excessive shift range switching due to temperature-related issues, leading to unnecessary prohibitions even when switching is possible, which can result in excessive heat generation suppression.
Innovation Solution
A shift range control device incorporating a temperature detection unit, a temperature estimation unit, an abnormality determination unit, and a switching prohibition unit that calculates and uses estimated temperatures to accurately determine when to prohibit shift range switching, based on actual and estimated temperatures, to prevent excessive prohibitions and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If shift range switching is prohibited when temperature reaches threshold to suppress heat generation, then heat generation is suppressed, but excessive prohibition occurs even when switching is possible
Solution Approach 1:
The system performs preliminary detection of temperature detection unit abnormalities before making switching prohibition decisions. By detecting abnormalities in advance through the abnormality determination unit, the system avoids excessive prohibition of shift range switching while still suppressing heat generation when appropriate.
Solution Approach 2:
The system uses feedback from the abnormality determination unit to adjust the switching prohibition logic. When the temperature detection unit is abnormal, the feedback signal changes the decision-making process, allowing switching to be permitted even when estimated temperature reaches the threshold, thereby preventing excessive prohibition.
2Reliability
If temperature detection unit is used to control shift range switching, then heat generation can be managed, but abnormality in detection unit causes excessive prohibition
Solution Approach 1:
The abnormality determination unit performs preliminary detection of temperature detection unit status before the switching prohibition decision is made. This preliminary action identifies detection abnormalities early, allowing the system to adjust its control strategy and avoid excessive prohibition of shift range switching.
Solution Approach 2:
The system dynamically adjusts the switching prohibition logic based on the operational status of the temperature detection unit. When the detection unit is normal, temperature-based prohibition is applied; when abnormal, the logic switches to allow switching despite temperature conditions, making the system adaptive to detection reliability.
3Temperature
If shift range switching is prohibited based on estimated temperature, then heat generation is suppressed, but switching may be prohibited unnecessarily
Solution Approach 1:
The system performs preliminary determination of temperature detection unit abnormality before relying on estimated temperature for switching prohibition decisions. This preliminary check ensures that when detection is abnormal, the system does not unnecessarily prohibit switching based on potentially inaccurate temperature estimates.
Data Source
AI summary
An ECU has a temperature detection unit that detects an actual temperature of the ECU, a temperature estimation unit that calculates an estimated temperature of the ECU, an abnormality determination unit for determining a presence or absence of a sign of abnormality, and a switching prohibition unit that prohibits the shift range switching in a predetermined case. The switching prohibition unit prohibits the shift range switching when there is no sign of abnormality in the temperature detection unit and the actual temperature is equal to or higher than a switching prohibition threshold, and prohibits the shift range switching when there is a sign of abnormality in the temperature detection unit and the estimated temperature is equal to or higher than a switching prohibition threshold. The temperature estimation unit calculates the estimated temperature based on a latest actual temperature in a normal period.