Hybrid Vehicle Control Device for Clutch Speed Stability

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Solution Overview

Problem

Conventional hybrid vehicle control devices face issues when switching from motor rotational speed control to engine rotational speed control, leading to undesirable decreases in engine rotational speed and transient torque output, which affects motor power generation.

Innovation Solution

A hybrid vehicle control device with a transient control mode switching mechanism that maintains motor rotational speed control alongside engine rotational speed control until engine torque stability is achieved, then switches to motor torque control, ensuring stable engine torque and suppressing variations in clutch input rotational speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the control is switched from motor rotational speed control to engine rotational speed control, then the motor power generation can be realized, but the engine rotational speed decreases and transient torque output is not generated

Engineering Contradiction:
Improvemotor power generationVSAvoidengine rotational speed stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system determines engine torque stability in advance before completing the control switch, ensuring that engine rotational speed control is only finalized when torque stability is confirmed, thus preventing speed drops and transient torque loss

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors engine torque stability and uses this feedback to control the timing of the switch from motor rotational speed control to engine rotational speed control, ensuring stable transition while maintaining power generation capability

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If the ignition timing is switched at engine torque control and engine rotational speed control, then the control flexibility is improved, but the engine rotational speed decreases when transient engine torque is not output

Engineering Contradiction:
Improvecontrol flexibilityVSAvoidengine rotational speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The system determines engine torque stability in advance before finalizing the ignition timing switch, ensuring that rotational speed control is maintained until torque stability is confirmed, thus preventing unwanted speed decreases while preserving control flexibility

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2631135B1Hybrid vehicle control device
Publication Date: 2020.08.26 NISSAN MOTOR CO LTD
  • EP2631135B1 patent drawingFigure 1~2
  • EP2631135B1 patent drawingFigure 3~5
  • EP2631135B1 patent drawingFigure 6~8

AI summary

The object of the present invention is to realize the motor electric power generation in the allowed range while suppressing the variation in the clutch input rotational speed when the input rotational speed control of the start clutch is switched from the motor rotational speed control to the engine rotational speed control. The hybrid vehicle control device has an engine 1, a motor/generator 2, a second clutch 5 as the start clutch, and a transient control mode switching means (FIG. 11). Here, the second clutch 5 is arranged in the driving force transmission system from the motor/generator 2 to the wheels 7 and 7 and is engaged under the input rotational speed control. The transient control mode switching means works as follows: when the input rotational speed control of the second clutch 5 is switched from the motor rotational speed control to the engine rotational speed control, the motor rotational speed control is maintained, and both the motor rotational speed control and the engine rotational speed control are carried out at the same time until a determination is made that the engine torque is stable; after a determination is made that the engine torque is stable, the control is switched from the motor rotational speed control to the motor torque control.