EV Powertrain Health Monitoring Through Bidirectional Torque Analysis

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Solution Overview

Problem

Monitoring the wear of complex powertrains in heavy electric vehicles is inefficient and costly due to the complexity of physical inspections, necessitating a more effective method for detecting mechanical wear in internal components like bearings.

Innovation Solution

A method involving analysis cycles where the electric motor is run in alternating directions to stabilize and measure torque, allowing for the establishment of a state of health by comparing these measurements to initial reference values, facilitating the detection of wear and defects within the powertrain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If physical inspection methods are used to monitor powertrain wear, then detection capability is provided, but the method is costly and inefficient

Engineering Contradiction:
Improvewear detection capabilityVSAvoidmonitoring efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces physical inspection methods with a torque-based monitoring system that uses electrical measurements to detect mechanical wear. The control unit measures torque values during motor operation and compares them to reference values, substituting direct mechanical inspection with indirect electrical measurement that is both more efficient and equally effective at detecting wear in powertrain components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If physical inspection of internal powertrain parts is performed, then wear detection is enabled, but the process is costly and time-consuming

Engineering Contradiction:
Improvewear detection accuracyVSAvoidinspection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The monitoring system operates continuously during normal motor operation without requiring vehicle shutdown or disassembly. Torque values are measured and compared to reference values in real-time, enabling continuous wear detection that eliminates the intermittent, time-consuming nature of periodic physical inspections while maintaining high reliability through ongoing assessment.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If complex powertrain systems are equipped with monitoring capabilities, then wear detection precision is improved, but the device complexity increases

Engineering Contradiction:
Improvestate of health monitoring precisionVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a control unit as an intermediary that leverages existing torque measurement capabilities already present in the motor control system. Rather than adding complex new sensors or measurement devices, the system uses the control unit to process and compare torque data, providing sophisticated wear detection through software-based analysis of existing hardware data.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If torque measurement is performed during motor operation, then wear monitoring is achieved, but the measurement conditions vary

Engineering Contradiction:
Improvemonitoring implementation easeVSAvoidtorque measurement consistency
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system compensates for varying measurement conditions by comparing torque values under different operational parameters. The control unit stores reference torque values obtained under specific conditions and compares current measurements against these references, accounting for variations in load, speed, and operating state. This allows accurate wear detection despite the inherent variability of torque measurements during dynamic motor operation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4468592A1Method for monitoring the state of health of a powertrain of an electric vehicle and electric vehicle implementing said method
Publication Date: 2024.11.27 VOLVO TRUCK CORP
  • EP4468592A1 patent drawingFigure 1
  • EP4468592A1 patent drawingFigure 2
  • EP4468592A1 patent drawing

AI summary

This method (100) for monitoring the state of health of a powertrain of an electric vehicle, wherein the powertrain comprises an electric motor and a drivetrain, wherein the drivetrain delivering the motor torque to mechanical components (12) of the electric vehicle, comprises an analysis cycle (120) that includes, in this order: - running (121) the electric motor in a first direction of rotation until a first preset speed of the electric motor is reached; - maintaining (122) the first preset speed until stabilization of the powertrain; - measuring (123) a first motor torque delivered by the electric motor to the drivetrain; and - establishing (127) a state of health of the powertrain by analyzing said first motor torque. The method further comprises comparing (130) the state of health established (127) during the analysis cycle (120A; 120B) of the powertrain to a reference value to detect wear of the powertrain.