Adaptive Shift Line Control for Vehicle Deceleration
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Solution Overview
Problem
Current vehicle shift control methods are inefficient in maintaining inter-vehicle distance and acceleration responsiveness, particularly when the preceding vehicle's speed changes, leading to inadequate deceleration and poor re-acceleration performance.
Innovation Solution
A method and apparatus that calculate the relative speed between a host vehicle and a preceding vehicle to determine if a shift line change condition is met, allowing for adaptive shift line adjustments based on inter-vehicle distance, relative speed, accelerator pedal position, vehicle speed, shift speed stage, and road gradient, enabling effective deceleration and improved acceleration responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the driver takes foot off the accelerator pedal to maintain inter-vehicle distance using coasting driving, then fuel economy is improved, but deceleration effectiveness deteriorates
Solution Approach 1:
The patent applies dynamics by making the shift line adaptive rather than fixed. The shift line is dynamically adjusted based on real-time relative speed between host vehicle and preceding vehicle, allowing the transmission to select optimal gear stages for deceleration while maintaining fuel efficiency through engine braking effects.
Solution Approach 2:
The patent changes the parameter of shift line based on relative speed conditions. When relative speed exceeds a threshold, the shift line is modified to enable lower gear engagement earlier, providing stronger engine braking force for effective deceleration while still utilizing coasting driving for fuel economy.
2Use of energy by moving object
If the shift speed stage is maintained at high stage during deceleration, then fuel economy is improved, but acceleration responsiveness deteriorates
Solution Approach 1:
The patent applies preliminary action by proactively lowering the shift line when relative speed is high, preparing the transmission for potential acceleration needs before they occur. This ensures that when the driver needs to accelerate, the vehicle is already in a lower gear stage ready to deliver power, improving acceleration responsiveness while maintaining fuel efficiency during the deceleration phase.
3Speed
If kick-down shift is performed when acceleration force is insufficient, then acceleration responsiveness is improved, but shift comfort deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the shift line to lower gear stages when relative speed indicates potential acceleration needs. This eliminates the need for sudden kick-down shifts, as the transmission is already positioned in appropriate lower gears, providing smooth and comfortable acceleration without abrupt shift shocks.
Data Source
AI summary
A method of controlling shifts based on a relative speed between a host vehicle and a preceding vehicle includes calculating the relative speed between the host vehicle and the preceding vehicle based on a speed of the host vehicle and an inter-vehicle distance between the host vehicle and the preceding vehicle, determining whether a change condition of a shift line before stopping is satisfied, changing the shift line before stopping if the change condition of the shift line before stopping is satisfied, and performing the shift using the shift line before stopping based on a position of an accelerator pedal and the speed of the host vehicle.