Torque Map Blending for Smooth Accelerator Response
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Solution Overview
Problem
Existing vehicle powertrain systems experience disconcerting changes in accelerator pedal response when switching between different torque maps, especially during automatic mode changes, leading to unexpected engine behavior and discomfort for the driver.
Innovation Solution
A method and system that gradually blends the torque characteristics between different maps, using a maximum rate of change and time for completion, ensuring a smooth transition by maintaining a weighted average of the original and target characteristics, and recalculating blending rates based on accelerator pedal position and torque differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vehicle automatically changes torque maps in response to terrain detection, then the vehicle adapts to different terrains effectively, but the driver experiences disconcerting sudden changes in accelerator pedal response
Solution Approach 1:
The patent applies dynamics by making the torque map transition dynamic and time-dependent rather than instantaneous. The system continuously blends between source and target torque maps over a transition period, allowing the accelerator pedal response to evolve smoothly rather than changing abruptly, thus maintaining driver comfort while adapting to terrain changes
Solution Approach 2:
The patent introduces an intermediary blending mechanism that mixes the source torque map and target torque map in varying proportions during the transition period. This intermediary blended torque map serves as a mediator between the two distinct torque characteristics, preventing sudden jumps in accelerator response while still achieving the desired terrain adaptation
2Reliability
If the vehicle switches between different torque maps, then the engine response matches the desired terrain characteristics, but the accelerator pedal sensitivity changes abruptly causing driver discomfort
Solution Approach 1:
The patent applies beforehand cushioning by initiating a gradual transition period before the target torque map is fully implemented. During this transition period, the system cushions the abrupt change by blending torque maps, preventing sudden shifts in accelerator pedal sensitivity that would cause driver discomfort, while still progressing toward the accurate terrain-matched engine response
3Productivity
If multiple torque maps are provided for different terrains, then the vehicle can optimize performance for each terrain type, but the system complexity increases with multiple maps and transition control
Solution Approach 1:
The patent applies parameter changes by using a time-based transition parameter to control the blending ratio between source and target torque maps. Instead of managing complex switching logic between multiple discrete maps, the system uses a unified approach where the same transition mechanism handles all map changes, reducing control complexity while maintaining terrain-specific performance optimization
Data Source
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AI summary
A method and system is disclosed for blending between torque maps of a source of propulsion of a vehicle. Embodiments of the present invention are particularly applicable to automatic selection of an alternative torque map in response to a change of vehicle operating condition, for example a change of terrain. Blending according to embodiments of the present invention may substantially avoid a step change in response of the source of propulsion as accelerator position is changed.