AWD Regenerative Braking Control With Dynamic Wheel Torque Split

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Solution Overview

Problem

All-wheel drive eco-friendly vehicles face limitations in regenerative brake efficiency due to a fixed braking force distribution ratio between front and rear wheels, which restricts energy recovery during varying braking conditions.

Innovation Solution

A method for controlling braking in AWD eco-friendly vehicles that predicts braking power and dynamically adjusts the front/rear wheel distribution ratio to prioritize energy recovery and transfer efficiency, using a hybrid control unit to determine the optimal distribution ratio based on predicted braking power and motor regeneration capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a fixed braking force distribution ratio is used between front and rear wheels, then the control system is simple, but regenerative brake efficiency is limited during varying braking conditions

Engineering Contradiction:
Improveregenerative brake efficiencyVSAvoidbraking control system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from a fixed braking force distribution ratio to a dynamic distribution ratio that changes based on braking conditions. The control unit calculates the distribution ratio in real-time according to the braking state, allowing the system to adapt to varying conditions and maximize regenerative brake efficiency without requiring complex hardware modifications

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of braking force distribution ratio from a constant value to a variable value that depends on braking conditions. By calculating and adjusting this ratio dynamically based on factors like braking force magnitude and vehicle state, the system optimizes energy recovery while maintaining simple control architecture

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If braking force is distributed to maximize energy recovery, then regenerative brake efficiency improves, but braking control complexity increases

Engineering Contradiction:
Improveenergy recovery during brakingVSAvoidbraking control ease
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The control unit automatically calculates and adjusts the braking force distribution ratio based on real-time braking conditions without requiring manual intervention. The system serves itself by using sensor data to determine optimal energy recovery strategies, maximizing regenerative braking while maintaining simple operation for the driver

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback from braking condition sensors to continuously adjust the braking force distribution ratio. By monitoring the braking state and automatically modifying the distribution to optimize energy recovery, the system improves energy efficiency while keeping the control process transparent and simple for the operator

Inventive Principle:
Principle #23Feedback

3Loss of energy

If a dynamic distribution ratio is calculated based on braking conditions, then regenerative brake efficiency is maximized, but calculation complexity increases

Engineering Contradiction:
Improveenergy recovery amountVSAvoidbraking power prediction complexity
Core Design Contradiction:
Loss of energyVSDifficulty of detecting and measuring

Solution Approach 1:

The control unit calculates the dynamic distribution ratio in advance based on predicted braking conditions and available regenerative brake capacity. By preparing the optimal distribution strategy before actual braking occurs, the system maximizes energy recovery while using straightforward calculation methods that do not require complex real-time analysis

Inventive Principle:
Principle #10Preliminary action

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

Enhances regenerative brake efficiency by optimizing the distribution of braking force between wheels, allowing for maximum energy recovery during braking, regardless of the required braking power.

Implementation Method 1

The hybrid electric vehicle (HEV) converts driving force of a wheel into electric energy to recharge a battery, which is referred to as braking energy regeneration or regenerative brake

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3815995B1Eco-friendly vehicle and method of controlling braking for the same
Publication Date: 2023.08.23 HYUNDAI MOTOR CO LTD

AI summary

A method of controlling braking of a vehicle having a transfer case disposed between a driving motor and a plurality of driving wheels including a main driving wheel and an auxiliary driving wheel includes determining a first required braking amount of the main driving wheel and a second required braking amount of the auxiliary driving wheel, comparing the first required braking amount with a regenerative brake available amount of the driving motor, and, as a result of the comparing, when the first required braking amount is equal to or greater than the regenerative brake available amount, distributing regeneration capability of the driving motor only to the main driving wheel, and when the first required braking amount is less than the regenerative brake available amount, distributing the regeneration capability to both the main driving wheel and the auxiliary driving wheel.