Shift-By-Wire Backup Power Control for Automatic Parking Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shift-by-wire systems cannot detect the working condition of the mains power supply and adjust the automatic transmission range accordingly when the main battery fails, leading to potential operational issues.
Innovation Solution
A backup power supply system with a power storage unit and control unit that supplies power to the shift-by-wire system and outputs an instruction signal to change the automatic transmission range to a parking range when specific voltage threshold conditions are met, indicating a mains power supply failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power storage unit supplies power to the shift-by-wire system when the mains power supply fails, then the shift-by-wire system can continue operating, but the system cannot detect the working condition of the mains power supply and adjust the transmission range accordingly
Solution Approach 1:
The control unit continuously monitors the output voltage of the mains power supply before complete failure occurs. By detecting voltage drops below threshold values and measuring the duration of these drops, the system proactively determines power supply failure and preemptively controls the actuator to shift to a neutral range or parking range, ensuring safe operation while maintaining detection capability.
Solution Approach 2:
The control unit continuously monitors the output voltage of the mains power supply and uses this feedback to determine whether a power supply failure has occurred. Based on the feedback from voltage threshold comparisons and duration measurements, the control unit adjusts the transmission range accordingly, maintaining the ability to adapt to power supply conditions while ensuring continuous operation through backup power.
2Reliability
If the system continuously monitors power supply voltage to detect failure conditions, then the system can adjust transmission range appropriately, but this increases system complexity and power consumption
Solution Approach 1:
The control unit monitors voltage parameter changes by comparing the output voltage of the mains power supply against two threshold values (first and second voltage thresholds). When the voltage drops below these thresholds for specified durations, the system determines power supply failure. This parameter-based monitoring approach provides reliable detection while maintaining relatively simple system architecture.
3Reliability
If the control unit outputs instruction signal to change transmission range to parking range, then the vehicle can be safely brought to halt, but this may cause accidental shifts if voltage fluctuations are misinterpreted as failure conditions
Solution Approach 1:
The control unit continuously monitors voltage and measures the duration that voltage remains below threshold values before triggering a shift range change. By requiring that the voltage remains below the threshold for a specified duration (first duration for first threshold, second duration for second threshold), the system performs preliminary verification to distinguish temporary fluctuations from actual power supply failures, preventing accidental shifts while maintaining the ability to safely halt the vehicle when genuine failures occur.
Data Source
AI summary
A backup power supply system for a shift-by-wire system includes a power storage unit and a control unit. Power storage unit supplies power to a shift-by-wire system. When at least one of a first condition or a second condition is satisfied, control unit outputs an instruction signal, instructing that a shift range of an automatic transmission should be changed into a parking range, to shift-by-wire system. First condition requires that the duration for which output voltage of the mains power supply remains equal to or less than a first voltage threshold value should be longer than a first duration. Second condition requires that the duration for which the output voltage of the mains power supply remains equal to or less than a second voltage threshold value, smaller than the first voltage threshold value, should be longer than a second duration which is shorter than the first duration.