Hybrid Vehicle Harness Power Control for Overheat and Drive Force

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Solution Overview

Problem

In hybrid vehicles, the temperature of electric wire harnesses can exceed their heatproof temperature when high electric power is supplied, leading to potential discomfort for drivers due to inadequate driving force and increased weight and cost issues with thickening or adding more harnesses to prevent overheating.

Innovation Solution

A method that reduces the upper limit value of electric power supplied to both vehicle electrical equipment and drive motors when the harness temperature reaches a predetermined level, with a greater reduction for the equipment to minimize temperature increase and maintain driving force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the harness is thickened to raise the heatproof temperature, then the heatproof temperature is improved, but the weight increases

Engineering Contradiction:
Improveheatproof temperatureVSAvoidharness weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The invention changes the operational parameters of the electrical equipment rather than modifying the physical structure of the harness. By reducing the upper limit value of electric power supplied to electrical equipment when harness temperature reaches a predetermined level, the system maintains adequate heat dissipation without requiring a thicker harness, thus avoiding weight increase while still preventing overheating.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If the upper limit value of electric power to the drive motor is reduced significantly, then the harness temperature is controlled, but the driving force becomes inadequate

Engineering Contradiction:
Improveharness temperatureVSAvoiddriving force
Core Design Contradiction:
TemperatureVSPower

Solution Approach 1:

The invention applies different degrees of power reduction to different components. Specifically, the upper limit value of electric power supplied to electrical equipment is reduced by a greater degree than that supplied to the drive motor. This selective approach ensures that the harness temperature is controlled while maintaining adequate driving force for the vehicle.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention creates an asymmetric power distribution strategy where electrical equipment and drive motors are treated differently during temperature control. The power reduction for electrical equipment is more significant than for drive motors, breaking the symmetry of uniform power management and optimizing both temperature control and driving performance.

Inventive Principle:
Principle #4Asymmetry

3Power

If more harnesses are added to supply power, then the power supply capacity is improved, but the cost and weight increase

Engineering Contradiction:
Improvepower supply capacityVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The invention implements dynamic power management that adjusts the upper limit value of electric power supplied to electrical equipment based on real-time harness temperature conditions. This dynamic control allows the existing harness infrastructure to operate within safe temperature limits while maintaining adequate power supply capacity, eliminating the need for additional harnesses and associated costs.

Inventive Principle:
Principle #15Dynamics

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 minimizes driver discomfort and temperature increase in the harnesses while avoiding weight and cost increments associated with thicker or additional harnesses, ensuring adequate power supply to the drive motors.

Implementation Method 1

when a temperature of the harness is equal to or greater than a predetermined temperature, upper limit values of electric power supplied from the electric power source to the vehicle electrical equipment and the drive motor are both reduced

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4201750B1Control method for hybrid vehicle and control device for hybrid vehicle
Publication Date: 2024.07.31 NISSAN MOTOR CO LTD
  • EP4201750B1 patent drawingFigure 1
  • EP4201750B1 patent drawingFigure 2
  • EP4201750B1 patent drawingFigure 3

AI summary

A method is provided for controlling a hybrid vehicle including an electric power source, a vehicle electrical equipment and a drive motor to which electric power is supplied from the electric power source. The vehicle electrical equipment and the drive motor are electrically connected to the electric power source via at least a shared harness. When a temperature of the harness is equal to or greater than a predetermined temperature, upper limit values of electric power supplied from the electric power source to the vehicle electrical equipment and the drive motor are both reduced, and a degree of reduction in the upper limit value for the vehicle equipment is greater than a degree of reduction in the upper limit value for the drive motor.