EV Gear-Approach Control for Torque Reversal Rattle

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Solution Overview

Problem

Electric vehicles experience significant vibration and noise due to gear rattle when the output torque of the electric machinery changes between positive and negative torque, affecting driving comfort and potentially causing damage to transmission mechanisms.

Innovation Solution

An electric-machinery control method that detects the relative deformation between a driving gear and a wheel end, determines a speed differential value, and controls the driving gear to perform a gear-approaching operation based on calculated output torque to reduce the speed difference upon re-contact, thereby minimizing vibration and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If torque smoothing processing method is used to reduce vibration and noise, then the harmful factors are reduced, but the vibration and noise remain large leading to poor driving experience

Engineering Contradiction:

Improvevibration and noiseVSAvoiddriving experience

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The control method performs preliminary action by detecting the relative deformation amount before gear disengagement occurs, and pre-calculates the speed differential value and output torque needed. The driving gear is controlled to perform gear-approaching operation in advance to reduce the speed difference upon re-contact, thereby preventing large vibration and noise before they occur rather than merely smoothing them after occurrence.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control method implements feedback by continuously detecting the relative deformation amount of the transmission system and using this information to dynamically adjust the output torque of the electric machinery. The controller calculates the speed differential value based on the detected deformation and adjusts the driving gear's rotational speed accordingly, creating a closed-loop control system that actively compensates for conditions leading to gear rattle.

Inventive Principle:

Principle #23Feedback

2Object-generated harmful factors

If filtering processing method is applied to output torque, then harmful factors are reduced, but large vibration and noise persist affecting driving comfort

Engineering Contradiction:

Improvegear rattleVSAvoidvibration and noise

Core Design Contradiction:

Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control method replaces mechanical filtering or damping mechanisms with an active control system that uses sensors to detect transmission system deformation and electronically controls the electric machinery's output torque. This substitution of mechanical solutions with control-based solutions allows for more precise and effective reduction of gear rattle and associated vibration and noise.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If gear-approaching operation is controlled by detecting relative deformation amount, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvegear meshing precisionVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control method implements self-service by using the transmission system's own relative deformation amount as the detection parameter. The existing sensors in the transmission system are utilized to detect the deformation, and this information is fed back to the controller which automatically adjusts the driving gear's rotational speed. This eliminates the need for additional specialized sensors or complex external monitoring systems, achieving precise gear meshing control through the system's inherent characteristics.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12491886B2Electric vehicle and electric-machinery control method therefor, apparatus and storage medium

Publication Date: 2025.12.09 ZHEJIANG ZEEKR INTELLIGENT TECH CO LTD

AI summary

The present application relates to the field of electric vehicles, and particularly to an electric vehicle and an electric-machinery control method therefor, an apparatus and a storage medium. The electric-machinery control method for the electric vehicle of the present application includes: detecting a relative deformation amount of a transmission system between a driving gear and a wheel end of an electric machinery; determining a first speed differential value between a first driving-gear rotational speed and a first wheel-end converted rotational speed when the relative deformation amount is a first threshold value; determining an output torque of the electric machinery according to the first speed differential value; controlling the driving gear to perform a gear-approaching operation relative to the driven gear according to the output torque.