Shift-by-wire capacitor backup for P-range engagement
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Solution Overview
Problem
Shift-by-wire systems in vehicles face challenges in secure parking and easy relocation when an abnormality occurs in the electric power source or electric power supply system, as they rely on electrical actuation, making it difficult to change the transmission shift range and potentially hinder towing.
Innovation Solution
A shift-by-wire system incorporating an automatic transmission, a range position changing mechanism driven by an electric motor, a capacitor for power storage, and a manual P range releasing mechanism that allows shifting without relying on the electric motor's drive force, enabling secure parking and easy relocation even during power source abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shift range is electrically controlled, then the ease of operation is improved, but the reliability deteriorates when power supply abnormality occurs
Solution Approach 1:
The capacitor is pre-charged from the power source during normal operation to store electric energy. When power supply abnormality occurs, the stored energy in the capacitor is activated to drive the shift range changing mechanism, enabling secure parking without real-time power supply.
Solution Approach 2:
The capacitor acts as an intermediary energy storage device between the power source and the shift range changing mechanism. It receives and stores electric energy from the power source, then releases this energy to the mechanism during power supply abnormalities, bridging the gap between normal and abnormal operating conditions.
2Reliability
If the P range is engaged for secure parking, then the security is improved, but the ease of operation deteriorates when towing is needed
Solution Approach 1:
The manual P range releasing mechanism is pre-positioned and ready for operation. When towing is needed, the operator can manually disengage the P range without requiring power supply or complex electrical systems, enabling quick vehicle relocation.
3Ease of operation
If the parking brake is electrically actuated, then the ease of operation is improved, but the reliability deteriorates when power supply abnormality occurs
Solution Approach 1:
The capacitor is pre-charged to store sufficient electric energy specifically for emergency parking brake actuation. When power supply abnormality occurs, this stored energy enables the parking brake to be activated, ensuring secure parking even without normal power supply.
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 secure parking and easy vehicle relocation by allowing the shift range to be changed to the P range using stored capacitor power and manually releasing it, ensuring safety and ease of towing even when the electric power supply is compromised.
Implementation Method 1
The capacitor stores an electric power to be supplied to the range position changing means and the range control means
Data Source
AI summary
A shift-by-wire (SBW) device includes a capacitor, which stores electric power. When an abnormality occurs in a battery or an electric power supply system, an actuator of the SBW device receives electric power from the capacitor and changes a shift range of an automatic transmission to a P range at least once. Furthermore, when a lever of a P range releasing arrangement is operated, the P range of the automatic transmission is released.