Hybrid Transmission Control for Shift Shock and Energy Efficiency
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Solution Overview
Problem
In hybrid vehicles, existing transmission apparatuses face challenges in suppressing shift shock while maintaining energy efficiency during upshifts with the accelerator pedal position equal to or smaller than a prescribed value, as limiting regenerative torque reduces energy regeneration efficiency.
Innovation Solution
A control apparatus that reduces release-side oil pressure to maintain a slipping state in the release-side element during shifting, synchronizing the rotation speeds of the input and output members, allowing regenerative torque to be managed without limiting its magnitude, thus preventing rapid rotation speed variations and maintaining energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If regenerative torque is limited to suppress shift shock, then shift shock is reduced, but energy regeneration efficiency deteriorates
Solution Approach 1:
The friction engagement element is controlled to maintain a dynamic semi-engaged state during shifting operations. The engagement state is continuously adjusted based on rotation speed differences, allowing the system to adaptively manage torque transmission while suppressing shift shock without limiting regenerative torque magnitude.
Solution Approach 2:
The control apparatus changes the engagement parameter of the friction engagement element during shifting. By adjusting the degree of engagement (from fully engaged to semi-engaged with controlled slip), the system can suppress shift shock while maintaining energy regeneration efficiency through optimized parameter management rather than torque limitation.
2Speed
If the release-side element is swiftly released fully at initial stage, then shifting speed is improved, but rotation speed synchronization deteriorates causing shift shock
Solution Approach 1:
The control apparatus performs preliminary engagement of the engage-side friction element before complete disengagement of the release-side element. This preliminary action ensures that the engage-side element is ready to承接 torque transmission, preventing sudden rotation speed changes and shift shock while maintaining efficient shifting speed.
Solution Approach 2:
The friction engagement element acts as an intermediary during the transition between engaged and released states. By controlling it to slip in a semi-engaged state rather than abrupt full release, the system mediates the torque transmission smoothly, preventing rotation speed synchronization issues and shift shock.
3Stability of the object's composition
If the friction engagement element is gradually engaged while slipping, then rotation speed synchronization is improved, but shifting time increases
Solution Approach 1:
The control apparatus applies partial engagement action to the friction engagement element, maintaining it in a semi-engaged slipping state rather than full engagement. This partial action achieves sufficient rotation speed synchronization while avoiding the excessive engagement time that would result from gradual full engagement, thus reducing overall shifting time.
Solution Approach 2:
The control apparatus periodically adjusts the engagement state of the friction engagement element during the shifting process. By cycling between controlled slip and reduced slip phases, the system achieves rotation speed synchronization more efficiently than continuous gradual engagement, thereby reducing total shifting time.
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 suppresses shift shock and improves energy efficiency by allowing regenerative torque to be managed without limiting its magnitude, ensuring smooth shifting operations and high energy regeneration.
Implementation Method 1
a release-side element that serves as a friction engagement element to be released among a plurality of friction engagement elements
Implementation Method 2
the pressure of hydraulic oil on the release-side element is reduced, and the release-side element is kept in a slipping state
Implementation Method 3
the rotating electrical machine is capable of generating regenerative torque based on a deceleration request of the vehicle
Data Source
AI summary
A control apparatus for controlling a transmission apparatus that includes: an input member that is drivably connected to a rotating electrical machine being capable of generating regenerative torque based on an engine and a deceleration request of a vehicle; an output member that is drivably connected to wheels; and a speed change mechanism that has a plurality of friction engagement elements that are controlled to be engaged and released so as to switch a plurality of shift speeds, and that shifts a rotation speed of the input member at one of gear ratios set for the shift speeds and outputs the shifted speed to the output member.