Vehicle Gear Shift Suppression Across Road Slope Changes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Frequent shifting during vehicle travel can lead to uncomfortable feelings for the driver due to immediate upshifting and downshifting based on drive force conditions, particularly when transitioning between segments with different road slopes.
Innovation Solution
A vehicle control device and method that selects current and next gear stages based on travel resistance, preventing upshifting to a target gear stage unless the engine rotational speed meets a predetermined value or the stall amount in the next segment is within a threshold, thereby reducing frequent shift changes and maintaining a stable gear during transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If shift transmission is performed based on drive force and travel resistance, then fuel consumption is minimized, but frequent upshifting and downshifting occurs causing driver discomfort
Solution Approach 1:
The system performs preliminary action by selecting a next gear stage in advance for the next travel segment before the vehicle actually enters it. This allows the control unit to predict future gear needs and prevent unnecessary frequent shifting by preparing the appropriate gear stage beforehand, thus reducing driver discomfort while maintaining fuel efficiency.
Solution Approach 2:
The system applies dynamics by making the gear stage selection adaptive and flexible. The control unit dynamically adjusts gear stage decisions based on real-time conditions (engine rotational speed, travel resistance) and predictive information (next travel segment characteristics). This dynamic approach allows the system to maintain optimal fuel consumption while avoiding unnecessary shifts that would cause driver discomfort.
2Ease of operation
If upshifting is prevented to maintain current gear stage, then driver discomfort is reduced, but engine rotational speed may become suboptimal
Solution Approach 1:
The system uses feedback by continuously monitoring engine rotational speed and comparing it against the selected next gear stage requirements. When the engine rotational speed meets or exceeds the predetermined value, the control unit receives feedback that conditions are favorable for upshifting, allowing the system to switch to the target gear stage without compromising driver comfort or engine performance.
Solution Approach 2:
The system applies parameter changes by using engine rotational speed as a key parameter to determine when upshifting should be permitted. By setting a predetermined rotational speed threshold, the system dynamically adjusts the gear stage based on this parameter, ensuring that upshifting occurs only when engine performance conditions are appropriate, thus balancing driver comfort with optimal engine operation.
3Use of energy by moving object
If gear stage is changed frequently to adapt to travel resistance changes, then fuel efficiency is optimized, but shift frequency increases causing uncomfortable feeling
Solution Approach 1:
The control unit performs preliminary action by selecting the next gear stage in advance based on travel resistance information for the next travel segment. This advance selection allows the system to smooth out unnecessary frequent shifts while still adapting to travel resistance changes, thereby optimizing fuel efficiency without causing driver discomfort from excessive shifting.
Data Source
AI summary
This vehicle control device 10 is provided with: a current gear stage selection unit 13 which, on the basis of the travel resistance of the vehicle, selects a current gear stage, which is the gear stage of the vehicle in the current travel segment where the vehicle is traveling; a next gear stage selection unit 16 which selects a next gear stage, which will be the gear stage of the vehicle in the next travel segment, forwards in the travel direction of the vehicle, having a road slope different from that of the current travel segment; and a shift control unit 17 which, if during travel of the vehicle in the current travel segment in the current gear stage, the current gear stage selection unit 13 has newly selected a target gear stage higher than the next gear stage, controls shifting such that upshifting from the current gear stage to the target gear stage is suppressed and the current gear stage is maintained. If, in a state in which upshifting is suppressed, the engine rotation speed reaches or exceeds a prescribed value during travel in the current travel segment, the shift control unit 17 controls shifting so as to upshift to the target gear stage without suppression of upshifting.