Vehicle Clutch Torque Control for Torsional Vibration Suppression

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Solution Overview

Problem

Vehicles experience significant torsional torque fluctuations during braking on corrugated roads, leading to increased stress on drive-system components due to the mismatch between brake control response frequencies and torsional resonance frequencies, which existing brake controllers cannot effectively suppress.

Innovation Solution

An electronic control unit is implemented to monitor and manage clutch torque capacity, engaging or disengaging the clutch to adjust torque transmission based on detected torsional torque fluctuations, thereby activating an engine brake to mitigate these fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wheel brake control is used to suppress torsional torque fluctuations, then braking effectiveness is improved, but the control system cannot respond effectively because brake actuator response frequency (at most 4 Hz) is lower than torsional torque fluctuation frequency (approximately 10 Hz)

Engineering Contradiction:
Improvebraking effectivenessVSAvoidcontrol response frequency
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The invention introduces the clutch as an intermediary device between the engine and drive wheels to suppress torsional torque fluctuations. Instead of directly controlling wheel brakes at their limited response frequency, the system uses the clutch actuator (capable of higher response frequency) to modulate torque transmission, thereby indirectly achieving suppression of torsional vibrations that brake control cannot handle directly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces the mechanical brake control system (hydraulically controlled with limited response frequency) with an electronic clutch control system. The electronic control unit directly controls the clutch actuator, substituting the slow hydraulic brake response with a faster electronic-clutch-based control mechanism that can respond to 10 Hz torsional fluctuations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If clutch torque capacity is increased to suppress torsional torque fluctuations, then durability of drive-system components is improved, but clutch engagement and disengagement timing must be precisely coordinated with braking operations

Engineering Contradiction:
Improvedurability of drive-system componentsVSAvoidclutch control coordination
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention implements a feedback control mechanism where the electronic control unit continuously monitors braking operations and torsional torque fluctuations, then adjusts clutch torque capacity accordingly. The control unit determines when to increase or decrease clutch torque capacity based on detected conditions, creating a closed-loop system that automatically coordinates clutch engagement with braking operations without requiring complex manual timing.

Inventive Principle:
Principle #23Feedback

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 torsional torque fluctuations, enhancing the durability of drive-system components by synchronizing clutch engagement and disengagement with braking operations to match the vehicle's speed and road conditions.

Implementation Method 1

a clutch (18) that connects and disconnects a power transmission route between the engine (12) and the drive wheel (14)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

engine brake that corresponds to an increased amount of the torque capacity of the clutch is actuated

Methodology Applied
Scientific EffectCompression braking: Compression

Data Source

PatentEP3211261B1Vehicle, controller for vehicle, and control method for vehicle
Publication Date: 2019.11.13 TOYOTA JIDOSHA KK
  • EP3211261B1 patent drawingFigure 1
  • EP3211261B1 patent drawingFigure 2
  • EP3211261B1 patent drawingFigure 3

AI summary

A clutch (18) is controlled to increase torque capacity (Tcl) of the clutch (18) when fluctuations in torsional torque generated in a power transmission route between the clutch (18) and a drive wheel (14) are larger than a specified value during deceleration traveling. Accordingly, engine brake whose magnitude corresponds to an increased amount of the torque capacity (Tcl) of the clutch (18) is actuated. Therefore, the fluctuations in the torsional torque can be suppressed by the engine brake.