Fluid Coupling Torque Control for Hybrid Power Transmission

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Solution Overview

Problem

Existing dynamic power transmission systems face challenges in maintaining driving torque and durability due to energy restriction in electric generators, leading to potential overheating and reduced clutch durability when excess energy is consumed by clutch friction.

Innovation Solution

A control apparatus that includes a differential mechanism, an electric generator, an electric motor, and a fluid coupling, with an electronic controller that restricts electric storage charging and controls the fluid coupling to generate dynamic power loss, ensuring sufficient engine torque and maximizing driving torque by equalizing unchargeable engine power with fluid coupling losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the electric generator is controlled to satisfy demand driving power, then the driving torque is sufficient, but the electric storage apparatus cannot be charged when already full, causing energy restriction

Engineering Contradiction:

Improvedriving torqueVSAvoidelectricity generation quantity

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful excess energy that cannot be charged into beneficial driving torque through the fluid coupling. The unchargeable electric power is transmitted to the fluid coupling, which converts it to mechanical torque to drive the vehicle, thus transforming waste energy into useful work.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the operating parameters of the fluid coupling (torque transmission capacity, slip ratio) based on the charging state of the electric storage apparatus. When charge is restricted, the system adjusts the fluid coupling to transmit the unchargeable power as torque, optimizing the parameter matching between power supply and power consumption.

Inventive Principle:

Principle #35Parameter changes

2Power

If excess energy is consumed by clutch friction to compensate torque decrease, then the driving torque is maintained, but the clutch temperature increases and durability decreases

Engineering Contradiction:

Improvedriving torqueVSAvoidclutch durability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent replaces the mechanical clutch friction method with a fluid coupling-based torque transmission system. The fluid coupling uses fluid dynamics rather than mechanical friction to transmit and convert torque, eliminating the direct contact friction that causes clutch overheating and durability issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs hydraulic principles through the fluid coupling to transmit power from the electric generator to the driving wheels. The fluid coupling uses hydraulic fluid to transfer energy, converting excess electric power into mechanical torque without the thermal problems associated with mechanical friction clutches.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Use of energy by moving object

If the fluid coupling generates dynamic power loss to consume unchargeable energy, then the electric storage charging is restricted without losing driving torque, but power is consumed as loss

Engineering Contradiction:

Improveelectric storage chargingVSAvoiddynamic power loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent converts the harmful dynamic power loss in the fluid coupling into beneficial driving torque. The energy that would normally be lost as heat in the fluid coupling is actually utilized to drive the vehicle, transforming what appears to be a loss into a useful output.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively relieves electricity generation restrictions and maintains engine torque, ensuring sufficient driving torque while minimizing power consumption and heat generation, thus enhancing system durability.

Implementation Method 1

control the fluid coupling to differentially rotate and to drive the electric motor by the electric power such that a dynamic power loss is generated in the fluid coupling

Methodology Applied

Scientific EffectDynamic power loss: Viscous Heating

Data Source

PatentUS10066718B2Control apparatus for dynamic power transmission apparatus

Publication Date: 2018.09.04 TOYOTA JIDOSHA KK

AI summary

A control apparatus for a dynamic power transmission apparatus is provided. The dynamic power transmission apparatus includes a differential mechanism, an electric generator, an electric motor, and a fluid coupling. The electric motor is disposed at a position apart from a transmission path along which a dynamic power of an engine is transmitted to a driving wheel. The fluid coupling is disposed between the electric motor and the transmission path. The control apparatus includes an electronic controller configured to restrict a charge of an electric storage apparatus with an electric power generated by the electric generator, depending on a state of the electric storage apparatus, and control the fluid coupling to differentially rotate and to drive the electric motor by the electric power such that a dynamic power loss is generated in the fluid coupling, when restricting the charge of the electric storage apparatus.