Hybrid Transmission Control Device for Smooth Shifts
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Solution Overview
Problem
In hybrid vehicle transmission devices, restricting regenerative torque to prevent speed change shocks lowers energy efficiency, and existing hydraulic control methods fail to effectively increase regenerated energy while maintaining smooth speed changes.
Innovation Solution
A control device that predicts negative torque and maintains the disengagement element in a slipping state during speed changes, allowing continuous rotational force transfer and preventing abrupt speed changes, thus avoiding the need to restrict regenerative torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If regenerative torque is restricted to prevent speed change shocks, then speed change smoothness is improved, but energy regeneration efficiency deteriorates
Solution Approach 1:
The control device predicts future negative torque conditions and preemptively adjusts the disengagement element's hydraulic pressure before the speed change occurs. By maintaining the disengagement element in a slipping state in advance, the system prepares for regenerative torque conditions, allowing full energy regeneration while preventing speed change shocks when they occur.
Solution Approach 2:
The system dynamically adjusts the disengagement element's engagement state based on predicted torque conditions. Instead of fixed engagement/disengagement, the control device continuously modulates hydraulic pressure to maintain optimal slipping control, enabling the system to adapt to varying regenerative torque conditions and achieve both smooth transitions and energy efficiency.
2Speed
If the disengagement element is completely disengaged quickly, then shift speed switching is faster, but speed change shocks increase
Solution Approach 1:
The control device begins adjusting the disengagement element's hydraulic pressure before the actual speed change is needed. By predicting future negative torque conditions, the system preemptively transitions the disengagement element to a controlled slipping state, so that when the speed change occurs, the transition is already smoothed and shock-free.
Solution Approach 2:
The disengagement element acts as an intermediary between the input and output members during speed changes. By maintaining it in a controlled slipping state rather than complete engagement or disengagement, the system creates a buffer that transfers torque smoothly, preventing direct shock transmission while still enabling speed ratio changes.
3Stability of the object's composition
If the disengagement element is maintained in a slipping state, then speed change shocks are suppressed, but hydraulic pressure control complexity increases
Solution Approach 1:
The control device uses predicted negative torque information as feedback to adjust hydraulic pressure in advance. By anticipating future conditions rather than reacting to current shocks, the system simplifies control logic while achieving smooth transitions. The prediction-based feedback mechanism replaces complex real-time shock detection and response with simpler preemptive adjustment.
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 suppresses speed change shocks and maintains high energy efficiency by allowing continuous energy regeneration without restricting regenerative torque, enhancing the hybrid vehicle's energy efficiency during speed changes.
Implementation Method 1
a hydraulic control system that supplies hydraulic oil at a predetermined hydraulic pressure to various components
Implementation Method 2
a speed change mechanism that has a plurality of friction engagement elements that are controllably engaged and disengaged
Data Source
AI summary
A control device for controlling a transmission configured such that when the speed change mechanism performs switching to a shift speed with a lower speed ratio in a negative torque prediction established state in which predicted input torque is negative, the predicted input torque being a predicted value of input torque input to the input member a predetermined determination reference time later, and being derived on the basis of variations in the input torque, special speed change control is executed in which a disengagement hydraulic pressure is lowered to cause a disengagement element to slip, and the disengagement element is maintained in a slipping state over an entire speed change process, which extends from a time point when the disengagement element starts slipping to a time point when a rotational speed is synchronized with a rotational speed of the input member.