Automatic Transmission Launch Ratio Selection Across Ambient Conditions
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Solution Overview
Problem
Existing multi-speed automatic transmissions face challenges in efficiently determining the launch ratio, especially when paired with alternative engines or vehicles, leading to increased complexity and cost due to the need for multiple shift maps and variants.
Innovation Solution
A method and calibrator system that determines the launch ratio by referencing ambient temperature, pressure, and gradient, allowing for the same transmission and shift map to be used across different vehicles and engines by adapting the launch ratio based on these conditions, thereby reducing the need for multiple variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple shift maps are provided for different engines and vehicles, then the transmission can be optimized for each specific application, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent implements a single universal shift map that can be applied across multiple engine and vehicle configurations. The system determines the appropriate launch ratio by referencing ambient conditions (temperature, pressure, gradient) rather than requiring separate shift maps for each application, making one shift map serve multiple functions and configurations.
Solution Approach 2:
The system changes the operating parameters (ambient temperature, ambient pressure, gradient) as inputs to determine launch ratio selection. By varying these environmental parameters rather than creating separate shift maps, the system adapts to different engines and vehicles using a single shift map, reducing complexity while maintaining versatility.
2Device complexity
If a single shift map is used across different engines and vehicles, then manufacturing and inventory costs are reduced, but the transmission may not be optimized for specific application conditions
Solution Approach 1:
The patent introduces ambient conditions (temperature, pressure, gradient) as intermediary parameters that mediate between the single shift map and the diverse application requirements. These environmental factors serve as intermediaries that allow one shift map to adapt to multiple different engines and vehicle configurations without requiring multiple specialized shift maps.
3Ease of operation
If launch ratio selection is based on driver experience and manual selection, then the system responds to immediate conditions, but it lacks automated adaptation to environmental factors like ambient temperature and pressure
Solution Approach 1:
The system implements feedback by continuously monitoring ambient conditions (temperature, pressure, gradient) and automatically adjusting the launch ratio selection based on these inputs. This automated feedback loop replaces manual driver selection with an intelligent system that adapts to environmental factors, improving both ease of operation and adaptability simultaneously.
Data Source
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AI summary
A method and apparatus for modifying the shift map of an automatically controlled vehicle transmission having individually selectable speed ratios. A calibrator determines launch ratio from a plurality of speed ratios and is responsive to ambient pressure and/or ambient temperature. The calibrator may be further responsive to engine speed, engine temperature, transmission temperature, gradient and direction of gradient.