Hybrid Power Train Torque Control Device
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Solution Overview
Problem
Hybrid vehicles experience discontinuous torque when switching from a stepless speed change state to a stepped speed change state due to reduced output torque, leading to inadequate torque transmission to the wheels.
Innovation Solution
A control device for a power train with a differential mechanism and a switching mechanism that allows relative rotation or fixes rotating elements, along with a transmission mechanism to maintain torque continuity by compensating for torque changes during state switching, utilizing both rotary electric machines and an internal combustion engine to manage torque distribution effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the output torque of the drive source is reduced at the time of switching from the stepless speed change state to the stepped speed change state, then the switch shock is restrained, but the torque transmitted to the wheels declines and torque becomes discontinuous
Solution Approach 1:
The control device performs preliminary action by switching the differential mechanism to the second state (prohibiting relative rotation) before completing the torque reduction, ensuring that the transmission mechanism is already in the stepped speed change state ready to receive and transmit the reduced torque without interruption or discontinuity to the wheels
2Ease of operation
If the switching mechanism prohibits relative rotation of rotating elements, then the stepped speed change state is achieved, but torque continuity to the wheels is compromised
Solution Approach 1:
The control device merges the functions of the differential mechanism state switching with the torque control mechanism, coordinating both actions so that the transmission mechanism simultaneously achieves the stepped speed change state and maintains continuous torque transmission to the wheels through integrated control
Data Source
AI summary
A control device is provided for a power train including: a differential mechanism having a first rotating element linked to a first rotary electric machine, a second rotating element linked to a second rotary electric machine and a third rotating element linked to an internal combustion engine; a switching mechanism that switches between a first state that permits relative rotation of the first, second and third rotating elements, and a second state that prohibits relative rotation thereof; and a transmission mechanism connected to the differential mechanism which transmits torque from the differential mechanism to a wheel. The control device includes: a first control portion that controls the switching mechanism so as to switch between the first and second states; and a second control portion that compensates for an amount of change in the torque transmitted to the wheel when the switching between the two states is performed.