Electric Motor Torque Control for Vehicle Start-Up

Solution Overview

Problem

In vehicles with electric motors as a drive force source, energy loss and wasteful heat generation occur when the electric motor torque is insufficient to overcome running resistance during start-up, leading to inefficient energy consumption and potential damage from excessive heat.

Innovation Solution

A control device that adjusts electric motor torque based on a predetermined torque control characteristic, implementing torque suppression control when the requested drive force is below a necessary start-up value to prevent unnecessary energy consumption and heat generation, and includes features like creep torque generation and heat limiting to maintain vehicle state and prevent slipping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the electric motor torque is increased to overcome running resistance during start-up, then the vehicle can start moving, but the electric motor wastefully consumes energy and generates heat when the vehicle remains stopped

Engineering Contradiction:

Improvevehicle drive forceVSAvoidelectric power consumption

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The control device dynamically adjusts the electric motor torque based on real-time vehicle state detection. When the vehicle is detected to be stopped despite torque application, the control device suppresses further torque increase, thereby dynamically adapting the torque output to actual driving conditions and avoiding wasteful energy consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control device implements a feedback mechanism by detecting whether the vehicle is actually moving or stopped. Based on this feedback information, the control device adjusts the torque control strategy - suppressing torque when the vehicle remains stopped despite torque application, and allowing normal torque increase when the vehicle successfully starts moving.

Inventive Principle:

Principle #23Feedback

2Force

If the electric motor torque is increased to overcome running resistance during start-up, then the vehicle can start moving, but the electric motor generates excessive heat when the vehicle remains stopped

Engineering Contradiction:

Improvevehicle drive forceVSAvoidelectric motor temperature

Core Design Contradiction:

ForceVSTemperature

Solution Approach 1:

The control device dynamically adjusts the electric motor torque based on real-time vehicle state detection. When the vehicle is detected to be stopped despite torque application, the control device suppresses further torque increase, thereby dynamically adapting the torque output to actual driving conditions and preventing excessive heat generation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control device implements a feedback mechanism by detecting whether the vehicle is actually moving or stopped. Based on this feedback information, the control device adjusts the torque control strategy - suppressing torque when the vehicle remains stopped despite torque application, and allowing normal torque increase when the vehicle successfully starts moving.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If the electric motor follows the torque control characteristic to match requested drive force, then the driver's acceleration request is satisfied, but energy is wasted when the requested drive force is insufficient for actual start-up

Engineering Contradiction:

Improvedriver's acceleration responseVSAvoidelectric power consumption

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The control device applies partial torque suppression when the vehicle is detected to be stopped despite torque application. Instead of completely disabling torque, it suppresses the torque increase to a程度 that prevents wasteful energy consumption while still maintaining the capability to start moving when conditions are favorable.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The control device dynamically adjusts the electric motor torque based on real-time vehicle state detection. When the vehicle is detected to be stopped despite torque application, the control device suppresses further torque increase, thereby dynamically adapting the torque output to actual driving conditions and avoiding wasteful energy consumption.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8738209B2Control device of vehicle drive apparatus

Publication Date: 2014.05.27 TOYOTA JIDOSHA KK

AI summary

It is provided a control device of a vehicle drive apparatus in a vehicle including an electric motor for driving drive wheels, the control device controlling an output torque of the electric motor in accordance with a predetermined electric motor torque control characteristic making the output torque of the electric motor larger when a requested drive force is greater such that a drive force of the vehicle becomes equal to the requested drive force requested by a driver, wherein when the stopped vehicle is started, if the requested drive force is equal to or less than a requested drive force judgment value set equal to or less than a necessary start-up drive force necessary for start-up of the vehicle, the control device provides electric motor torque suppression control suppressing the output torque of the electric motor below an output torque determined from the electric motor torque control characteristic.