Vehicle Shift Control Device Adaptive Range Selection
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Solution Overview
Problem
When a communication abnormality occurs in a vehicle, preventing the transmission of a shift position determination signal from the shift position deciding portion to the drive power output command portion, the vehicle is unable to run and cannot ensure evacuation to a safe stopping place, as existing systems always switch to a neutral position, preventing any movement.
Innovation Solution
A vehicle shift control device that selects a shift range based on the shift position determination signal, maintaining the shift range at the time of communication abnormality if the vehicle speed is above a predetermined value, and switching to a neutral range if below, while imposing drive power limitations and activating the parking lock if necessary, to enable controlled evacuation and prevent unnecessary range switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power transmission device is always switched to a neutral position when a communication abnormality occurs, then safety is improved by preventing erroneous operation, but the vehicle becomes unable to run and cannot ensure evacuation running to a stopping place
Solution Approach 1:
The patent applies dynamics by making the shift range selection adaptive rather than static. When a communication abnormality occurs, the system dynamically adjusts the shift range based on real-time vehicle speed conditions: maintaining the current shift range when vehicle speed is above the threshold to enable evacuation running, and switching to neutral range when vehicle speed is at or below the threshold to ensure safety. This dynamic response resolves the contradiction between safety and evacuation capability.
2Reliability
If the power transmission device is switched to a neutral position when communication abnormality occurs, then erroneous operation is prevented, but the vehicle loses the ability to move to a safe stopping place
Solution Approach 1:
The patent applies parameter changes by using vehicle speed as a critical parameter to determine the appropriate shift range during communication abnormalities. The system monitors vehicle speed continuously and changes the shift range parameter based on whether the speed exceeds a predetermined threshold. This parameter-based decision-making enables the system to maintain productivity (evacuation capability) when safe to do so, while ensuring error prevention when vehicle speed is low.
3Ease of operation
If the shift range is maintained during communication abnormality when vehicle speed is high, then evacuation running is enabled, but drive power must be limited to prevent unsafe acceleration
Solution Approach 1:
The patent applies preliminary anti-action by proactively limiting drive power when the system detects that the maintained shift range corresponds to a forward or reverse running range during communication abnormalities. Before the vehicle can accelerate to unsafe levels, the control device preemptively restricts the drive power to prevent excessive acceleration, thereby enabling evacuation running while maintaining safety through power limitation.
Data Source
AI summary
A vehicle shift control device comprises: a shift position deciding portion deciding a shift position of a shift operating device based on a sensor signal output according to an operation of the shift operating device; and a drive power output command portion selecting a shift range based on a shift position determination signal output from the shift position deciding portion to cause a vehicle to run, when a communication abnormality has occurred so that the shift position determination signal is not transmitted from the shift position deciding portion to the drive power output command portion, the vehicle shift control device selecting a shift range maintained at the time of occurrence of the communication abnormality of the shift position determination signal if a vehicle speed is equal to or greater than a predetermined value, and selecting a neutral range if the vehicle speed is less than the predetermined value.