Gearbox Shaft Synchronization Using Supercapacitor Buffer

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Solution Overview

Problem

Current gear change systems in hybrid or electric motor vehicles with automatic gearboxes face challenges in synchronizing primary and secondary shafts efficiently, particularly during upshifts, where energy recovery is limited by battery charge levels, and downshifts, where high power is required but not efficiently supplied, affecting driving pleasure and energy recovery.

Innovation Solution

A device that uses an inverter for regenerative braking to convert kinetic energy into electrical energy, storing it in a battery and energy buffer, such as supercapacitors, allowing for maximum power supply and reception regardless of battery charge levels, and a control unit to manage energy transfer for optimal synchronization and energy recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If regenerative braking is used to recover kinetic energy during upshift, then energy recovery is improved, but the battery charge level limits the amount of energy that can be recovered

Engineering Contradiction:
Improvekinetic energy recoveryVSAvoidbattery charge capacity
Core Design Contradiction:
Loss of energyVSQuantity of substance

Solution Approach 1:

The energy storage system is segmented into two distinct components: a battery for long-term energy storage and a supercapacitor buffer for short-term high-power energy exchange. This segmentation allows the supercapacitor to handle the transient energy recovery during upshift regardless of battery charge level, while the battery provides sustained energy management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The supercapacitor buffer acts as an intermediary between the regenerative braking system and the battery. It temporarily stores the kinetic energy recovered during upshift, enabling energy recovery even when the battery is nearly full, and then transfers this energy to the battery when appropriate, thus mediating the charge level constraint.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If high power is supplied to accelerate the primary shaft during downshift, then synchronization speed is improved, but the available power is limited by battery charge level

Engineering Contradiction:
Improveprimary shaft acceleration speedVSAvoidavailable electrical power
Core Design Contradiction:
SpeedVSPower

Solution Approach 1:

The power supply system is segmented into two functional components: the battery provides sustained power for vehicle operation, while the supercapacitor buffer provides high-power transient bursts specifically for shaft synchronization during downshift, eliminating the power limitation imposed by battery charge level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The supercapacitor buffer provides excessive power capacity relative to the battery alone, enabling the system to deliver the high power needed for rapid shaft acceleration during downshift. This partial system (supercapacitor) compensates for the power limitation of the complete system (battery+supercapacitor) under extreme conditions.

Inventive Principle:
Principle #16Partial or excessive action

3Loss of time

If synchronization time is reduced to improve driving pleasure, then response time is improved, but the power requirements increase significantly

Engineering Contradiction:
Improvesynchronization timeVSAvoidpower required for synchronization
Core Design Contradiction:
Loss of timeVSPower

Solution Approach 1:

The power delivery system is segmented such that the supercapacitor buffer handles the high-power transient demands of rapid synchronization, while the battery provides baseline power support. This segmentation enables reduced synchronization time without overloading the battery, as the supercapacitor absorbs the power surge requirements.

Inventive Principle:
Principle #1Segmentation

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 solution enables efficient energy recovery and improved driving pleasure by ensuring consistent power supply during gear changes, reducing synchronization time and enhancing energy storage capabilities while maintaining energy levels across varying battery charges.

Implementation Method 1

uses an inverter for regenerative braking to convert kinetic energy into electrical energy

Methodology Applied
Scientific EffectRegenerative braking: Electromagnetic Induction

Implementation Method 2

energy buffer, such as supercapacitors, allowing for maximum power supply and reception

Methodology Applied
Scientific EffectCapacitance energy storage: Capacitance

Data Source

PatentEP3455523B1Device for synchronising a pinion on a shaft of a gearbox in regeneration mode, and corresponding method and motor vehicle
Publication Date: 2020.11.25 RENAULT SA
  • EP3455523B1 patent drawingFigure 1~2b
  • EP3455523B1 patent drawingFigure 3~4
  • EP3455523B1 patent drawingFigure 5a~6

AI summary

A device for synchronising a primary speed of a primary shaft (1, 6) receiving an electrical torque from an electric machine (7), with a secondary speed lower than the primary speed of a secondary transmission shaft (10), the primary shaft (1, 6) and secondary shaft (10) being decoupled, the primary shaft (1, 6) having a kinetic energy associated with the primary speed, the device being characterised in that it comprises means for providing electrical braking torque to the primary shaft (1, 6) until the primary speed is substantially equal to the secondary speed, and means for at least partially recovering, in the form of electrical energy, the kinetic energy lost by the primary shaft (1, 6) and transmitting said electrical energy to an energy storage means.