Hybrid Vehicle Clutch Temperature Control via Drive Mode Switching

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Solution Overview

Problem

The existing control apparatus for hybrid vehicles is prone to overheating of the second clutch during low shift ratio and extremely low vehicle speed travel, which can lead to clutch deterioration and reduced performance.

Innovation Solution

A control apparatus and method that includes a temperature detector for the second clutch and a controller to select between an engine-used slip drive mode and a motor drive mode based on clutch temperature, adjusting the operation of the first and second clutches, engine, and motor to prevent overheating, by engaging or disengaging them accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the second clutch is slipped to secure independent revolution of the engine at low shift ratio and extremely low vehicle speed, then the engine can operate independently, but the second clutch overheats

Engineering Contradiction:
Improveengine independent operationVSAvoidsecond clutch temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The control apparatus changes the operating parameters of the hybrid vehicle by switching between engine-used slip drive mode and motor drive mode based on second clutch temperature. When temperature exceeds threshold, the system transitions to motor drive mode, changing the power source parameter from engine to motor, thereby reducing clutch temperature while maintaining vehicle operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically adjusts the drive mode based on real-time second clutch temperature feedback. The control apparatus continuously monitors temperature and dynamically switches between engagement modes (engine-used slip drive with first clutch engaged vs. motor drive with first clutch disengaged), making the system adaptive to thermal conditions

Inventive Principle:
Principle #15Dynamics

2Duration of action of stationary object

If the second clutch is continuously slipped during low shift ratio travel, then the engine maintains independent revolution, but clutch durability decreases

Engineering Contradiction:
Improveengine continuous operationVSAvoidsecond clutch durability
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The control apparatus implements periodic action by alternately switching between engine-used slip drive mode and motor drive mode when second clutch temperature exceeds the threshold value. This periodic switching allows the clutch to cool down during motor drive intervals while maintaining engine operation, preventing continuous thermal stress and improving durability

Inventive Principle:
Principle #19Periodic action

3Temperature

If the drive mode is switched based on clutch temperature, then clutch overheating is suppressed, but control system complexity increases

Engineering Contradiction:
Improvesecond clutch temperature controlVSAvoidcontrol apparatus complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The control apparatus employs feedback control by continuously monitoring second clutch temperature through a temperature sensor and using this feedback to determine drive mode selection. The temperature threshold comparison and mode switching logic provide a straightforward feedback mechanism that manages clutch temperature without requiring complex control algorithms

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses self-service by leveraging the existing temperature sensor and control apparatus to automatically monitor and regulate second clutch temperature. The control system serves itself by using its own components (temperature sensor, mode selection logic) to manage thermal conditions without requiring external intervention or additional complex subsystems

Inventive Principle:
Principle #25Self-service

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

The solution effectively suppresses clutch overheating, enhances durability, and maintains efficient vehicle operation by dynamically managing the drive modes based on clutch temperature and vehicle load, thereby preventing overheating and ensuring continuous performance.

Implementation Method 1

a temperature detector for detecting a temperature of the second clutch

Methodology Applied
Scientific EffectTemperature detection:

Implementation Method 2

a first clutch installed between the engine and the motor, the first clutch configured to connect and disconnect the engine and the motor, a second clutch installed between the motor and drive wheels

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2065244B1Control apparatus of a hybrid vehicle and method for controlling the same
Publication Date: 2012.08.15 NISSAN MOTOR CO LTD
  • EP2065244B1 patent drawingFigure 1
  • EP2065244B1 patent drawingFigure 2~3
  • EP2065244B1 patent drawingFigure 4~5

AI summary

Disclosed herein are embodiments of a control apparatus for a hybrid vehicle that is capable of suppressing overheating of the second clutch. Control is switched between engine-used slip drive control and motor drive control on a basis of a temperature of the second clutch. Control methods for a hybrid vehicle are also disclosed.