Torque Vectoring Electric Machine Slip Control

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Solution Overview

Problem

During vehicle turns, weight distribution changes can cause driven wheels to slip, reducing stability and propulsion efficiency, and traditional braking methods to prevent slip often increase energy consumption.

Innovation Solution

A vehicle operating method that adjusts the torque output of a torque vectoring electric machine based on the speed difference between actual and natural wheel speeds, using a controller to generate appropriate torque changes to prevent wheel slip without relying on friction braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If friction braking is applied to prevent wheel slip during turns, then wheel slip is reduced, but energy consumption increases

Engineering Contradiction:

Improvewheel slip controlVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical friction braking system with an electric torque vectoring system. The torque vectoring electric machine generates compensating torque to counteract wheel slip caused by weight transfer during turns, eliminating the need for friction braking and thereby reducing energy consumption while maintaining wheel slip control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system dynamically adjusts the torque output parameter of the torque vectoring electric machine based on detected wheel slip conditions. By changing the torque parameter in response to speed differences between wheels, the system prevents wheel slip without the energy-intensive friction braking approach.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If friction braking is applied to prevent wheel slip during turns, then wheel slip is reduced, but vehicle speed decreases

Engineering Contradiction:

Improvewheel slip controlVSAvoidvehicle speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent replaces friction braking with electric torque vectoring that actively compensates for wheel slip by generating opposing torque through the electric machine. This substitution maintains vehicle speed while preventing wheel slip, unlike friction braking which inherently reduces speed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If torque output of torque vectoring electric machine is adjusted based on speed difference, then wheel slip is controlled smoothly, but control system complexity increases

Engineering Contradiction:

Improvewheel slip controlVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control system continuously monitors the speed difference between wheels and uses this feedback to adjust the torque output of the torque vectoring electric machine. This closed-loop feedback control enables smooth wheel slip prevention while managing system complexity through adaptive rather than overly complex control architecture.

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

This approach effectively reduces wheel slip while conserving energy by smoothly adjusting torque distribution between wheels, improving torque control and reducing energy consumption.

Implementation Method 1

adjusting torque output of a torque vectoring electric machine via a controller in response to a speed difference between an actual wheel speed and a natural wheel speed

Methodology Applied

Scientific EffectElectromagnetic torque generation: Electromagnetic Induction

Data Source

PatentUS10899237B2Methods and system for torque vectoring

Publication Date: 2021.01.26 FORD GLOBAL TECH LLC

AI summary

Methods and systems are provided for operating a vehicle during operating conditions where wheel slip may occur. In one example, a torque vectoring electric machine torque output is adjusted to direct propulsion torque from one wheel to a different wheel. Additionally, the propulsive torque is adjusted responsive to a driver demand wheel torque.