Automatic Transmission Shift Control Using Multiple Maps
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Solution Overview
Problem
Conventional shift control apparatuses for automatic transmissions in vehicles with constant speed traveling capabilities struggle to respond effectively to various traveling situations, leading to poor drivability and brake hunting issues, especially on uphill and downhill roads, and fail to provide sufficient acceleration performance.
Innovation Solution
A shift control apparatus that utilizes multiple shift maps, selected based on a shift-down request signal from a constant speed traveling control device, to optimize transmission ratio changes, ensuring appropriate acceleration and deceleration performance while minimizing brake intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single shift map is used for constant speed traveling control, then the control system is simple, but the system cannot respond to various traveling situations (uphill, downhill, merging, departing) and causes poor drivability with brake hunting
Solution Approach 1:
The patent divides the single shift map into multiple shift maps (first shift map for acceleration situations, second shift map for deceleration situations, and normal shift map for ordinary conditions). This segmentation allows the system to select the appropriate shift map based on the current traveling situation, thereby improving adaptability while maintaining manageable system complexity through structured organization.
Solution Approach 2:
The patent implements dynamic switching between different shift maps based on detected traveling situations. The shift map selection is not fixed but changes dynamically according to whether the vehicle is accelerating, decelerating, merging, or departing, allowing the system to adapt to varying conditions in real-time.
2Ease of operation
If the shift control suppresses speed changes during constant speed traveling, then comfort is improved, but acceleration performance is insufficient when preceding vehicle accelerates or during uphill traveling
Solution Approach 1:
The patent applies different shift control characteristics to different situations: the first shift map provides larger transmission ratio changes for better acceleration response when needed, while the second shift map provides smoother control for comfort during deceleration. This local differentiation of control quality allows the system to optimize for either comfort or acceleration performance depending on the specific situation.
3Productivity
If the shift control provides large acceleration response, then following ability is improved, but brake intervention increases reducing comfort
Solution Approach 1:
The patent uses feedback from the detecting device about surrounding situations (preceding vehicle speed, inter-vehicle distance, road gradient) to determine which shift map to select. This feedback mechanism allows the system to anticipate when acceleration is needed and proactively select the appropriate shift map, improving following ability while avoiding unnecessary brake intervention that would reduce comfort.
Data Source
AI summary
There is provided a shift control apparatus of an automatic transmission in a vehicle including a constant speed traveling apparatus, which has a detecting device detecting a surrounding situation of the vehicle and operates according to the detected situation, and an automatic transmission capable of steplessly changing a transmission ratio, the shift control apparatus controlling the automatic transmission according to a shift map for changing the transmission ratio according to a traveling state. The shift control apparatus includes a plurality of shift maps, and a switching and selecting unit selecting and switching to one of the shift maps based on a shift-down request signal or a requested acceleration, which is outputted by a constant speed traveling control device of the constant speed traveling apparatus, according to the situation detected by the detecting device.