Hybrid Vehicle Coasting Control via AMT Regenerative Braking Torque
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Solution Overview
Problem
Hybrid vehicles with Automated Manual Transmission (AMT) face challenges in controlling regenerative braking, especially in large-sized commercial vehicles where the degree of brake pedal manipulation cannot be accurately determined, leading to decreased coasting distance, frequent clutch operation, and reduced driving quality and durability.
Innovation Solution
A system and method that vary the amount of regenerative braking based on the degree of accelerator pedal manipulation within a predetermined control range, using a conversion map to calculate a deceleration request conversion index and adjust the regenerative braking torque accordingly, allowing for intentional coasting and increased coasting distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is performed with a predetermined deceleration request torque based on vehicle speed, then energy recovery is maximized, but coasting distance is reduced and driving quality deteriorates
Solution Approach 1:
The patent applies dynamics by making the regenerative braking torque adjustable based on accelerator pedal position. The system transitions from a static predetermined torque to a dynamic torque that varies with driver input, allowing the regenerative braking force to be modulated according to the degree of accelerator pedal depression, thus optimizing both energy recovery and coasting distance
Solution Approach 2:
The patent changes the parameter of regenerative braking torque from a fixed value to a variable value based on accelerator pedal position. By mapping the accelerator pedal position to different deceleration request torque values, the system dynamically adjusts the braking force parameter to balance energy recovery efficiency with desired coasting characteristics
2Power
If deceleration request torque is increased to improve energy recovery, then regenerative braking effectiveness is improved, but coasting properties deteriorate
Solution Approach 1:
The system dynamically adjusts the regenerative braking torque based on the accelerator pedal position, transitioning from a fixed high torque that harms coasting to a variable torque that adapts to driver intent, maintaining coasting speed when minimal pedal input is detected
3Speed
If clutch is frequently connected and disconnected to maintain vehicle speed, then vehicle speed is maintained, but clutch durability decreases and driving quality deteriorates
Solution Approach 1:
The patent replaces the mechanical clutch operation with an electrical control mechanism. Instead of using clutch engagement/disengagement to maintain vehicle speed, the system uses electric motor regenerative braking with adjustable torque based on accelerator pedal position, eliminating mechanical wear while maintaining speed control
4Ease of operation
If regenerative braking torque is reduced to improve coasting distance, then coasting properties are improved, but energy recovery efficiency decreases
Solution Approach 1:
The system changes the regenerative braking torque parameter from a single fixed value to a spectrum of values based on accelerator pedal position. This allows the torque parameter to be optimized for each operating condition, achieving high energy recovery when full braking is needed while enabling extended coasting when minimal braking is applied
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively increases coasting distance, improves driving quality, and enhances clutch durability by reducing frequent clutch operations and optimizing fuel efficiency.
Implementation Method 1
a motor, and an AMT... both the power of the engine and the power of the motor are supplied to the input shaft of the AMT... regenerative braking function... increasing the amount of energy recovery by increasing the amount of regenerative braking
Data Source
AI summary
A technique for controlling coasting of a hybrid vehicle equipped with an Automated Manual Transmission (AMT) is disclosed herein. First, the amount of regenerative braking is varied based on the degree of manipulation of an accelerator pedal within the predetermined control range of a total degree of manipulation of the accelerator pedal from when the accelerator pedal is not being manipulated. The amount of regenerative braking decreases as the degree of manipulation of the accelerator pedal increases. The control range is used to perform control in such a way as to vary the amount of regenerative braking according to the amount of manipulation of the accelerator pedal. Further, the control range is set to within a range of initial 5 to 20% of the total degree of manipulation of the accelerator pedal.