Hybrid Vehicle DCT Control for Regenerative Braking Efficiency
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Solution Overview
Problem
Dual clutch transmissions (DCTs) in hybrid electric vehicles face a trade-off between shift responsiveness and fuel efficiency due to pre-selection, which causes drag loss and deviates driving points from high regeneration efficiency regions, especially in regenerative braking mode.
Innovation Solution
A method and apparatus for controlling a hybrid electric vehicle that determines coasting and deceleration conditions to selectively connect a speed gear to an output shaft and lock up a shift clutch, optimizing gear shifts to improve responsiveness and efficiency by inhibiting pre-selection when not necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pre-selection is performed in regenerative braking mode to improve shift responsiveness, then shift responsiveness is improved, but fuel efficiency deteriorates due to drag loss
Solution Approach 1:
The patent applies dynamics by making the pre-selection operation conditional rather than fixed. The control device dynamically adjusts whether to perform pre-selection based on real-time detection of driving conditions, specifically identifying regenerative braking mode and preventing pre-selection during this mode. This dynamic adaptation resolves the contradiction by allowing pre-selection only when it benefits responsiveness without incurring unnecessary drag loss during regenerative braking.
Solution Approach 2:
The patent changes the operational parameter of the speed gear connection based on detected driving conditions. When regenerative braking mode is detected, the system changes the state from 'pre-selection enabled' to 'pre-selection disabled', thereby adjusting the mechanical engagement parameters to eliminate drag loss while maintaining shift responsiveness in other operating modes.
2Loss of energy
If pre-selection is not performed in regenerative braking mode to improve fuel efficiency, then fuel efficiency is improved, but shifting time is lengthened and driving points deviate from high regeneration efficiency regions
Solution Approach 1:
The control device changes the operational parameter of the transmission system based on detected driving conditions. By identifying regenerative braking mode through parameter detection (accelerator pedal position, brake pedal position, vehicle speed), the system adjusts the pre-selection parameter to be disabled during regenerative braking, thereby maintaining fuel efficiency while preventing unnecessary drag loss.
Solution Approach 2:
The patent implements feedback by continuously detecting driving conditions (accelerator pedal position, brake pedal position, vehicle speed) and using this information to control whether pre-selection is performed. This closed-loop feedback mechanism ensures that pre-selection is disabled during regenerative braking mode, optimizing both fuel efficiency and shifting performance based on real-time system state.
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 enhances shift responsiveness and fuel efficiency by ensuring the driving points of the motor remain within high regeneration efficiency regions, reducing drag loss and improving overall energy utilization.
Implementation Method 1
a regenerative braking mode in which braking and inertial energy are recovered through electrical power generation of the driving motor during braking of the vehicle
Implementation Method 2
shifting is achieved by operation of friction elements (clutches and brakes) including a planetary gear train
Data Source
AI summary
A method and an apparatus for controlling a hybrid electric vehicle are provided. The method includes: determining whether a coasting condition is satisfied and whether a current gear stage is greater than or equal to a predetermined gear stage; determining whether a brake pedal is pushed when the coasting condition is satisfied and the current gear stage is greater than or equal to the predetermined gear stage; determining whether deceleration of the hybrid electric vehicle is less than a predetermined deceleration when the brake pedal is pushed; connecting a speed gear to an output shaft when the deceleration of the hybrid electric vehicle is less than the predetermined deceleration; determining whether a shift condition before stopping from a current gear stage to a target gear stage is satisfied; and locking up a shift clutch when the shift condition before stopping is satisfied.