Hybrid Vehicle Controller Torque Optimization

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Solution Overview

Problem

In hybrid vehicles using both an internal combustion engine and a motor generator as power sources, increasing the motor generator's power-running-side output to reduce engine fuel consumption leads to short-term energy efficiency gains but results in increased fuel consumption over time due to decreased electric storage charging, thereby deteriorating gasoline mileage.

Innovation Solution

A hybrid-vehicle controller that calculates and optimizes the motor generator's torque demand to balance energy consumption between the engine and motor generator, selecting torque values that minimize overall energy consumption and maximize fuel efficiency by adjusting the relative supply power variation ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the motor generator's power-running-side output is increased to reduce engine fuel consumption, then short-term energy efficiency is improved, but long-term fuel economy deteriorates due to decreased electric storage charging

Engineering Contradiction:

Improveenergy efficiencyVSAvoidfuel consumption

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The control device calculates the supply variation amount ratio of engine supply power to MG supply power, and uses this feedback information to determine the optimal MG demand torque. By continuously monitoring and adjusting based on the calculated ratio, the system achieves optimal balance between energy efficiency and fuel consumption without requiring complex trial-and-error processes.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the operating parameters by calculating different supply variation amount ratios and selecting MG demand torque values that optimize the balance between engine and MG power supply. This parameter optimization allows the system to achieve both short-term energy efficiency and long-term fuel economy.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If the motor generator's power-running torque is increased to reduce engine fuel consumption, then energy consumption is reduced, but the electric storage device charging amount decreases

Engineering Contradiction:

Improveenergy consumptionVSAvoidcharging amount

Core Design Contradiction:

Loss of energyVSQuantity of substance

Solution Approach 1:

The control device uses feedback from the calculated supply variation amount ratio to determine the appropriate MG demand torque that maintains adequate charging while reducing energy consumption. The system adjusts MG torque based on the observed balance between engine and MG power supply variations.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If trial-and-error methods are used to determine optimal MG demand torque, then accuracy may be improved, but computational complexity and time increase

Engineering Contradiction:

Improvecalculation accuracyVSAvoidcontrol complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex trial-and-error control mechanisms with a direct calculation approach. By computing the supply variation amount ratio and using it to determine MG demand torque through formulaic relationships, the system achieves accurate results without the computational overhead and complexity of iterative trial-and-error methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The controller effectively reduces engine fuel consumption and increases motor generator power generation efficiency, leading to improved long-term fuel economy by optimizing torque demand and adjusting power distribution between the engine and motor generator.

Implementation Method 1

a motor generator (MG) as a driving power source for wheels (109)... an MG supply electric power calculation unit that calculates, for each of a plurality of MG torque candidate values, an MG supply electric power which is an electric energy that is converted by the motor generator

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

an internal combustion engine (hereinafter, referred to as an engine)... an engine supply fuel power calculation unit that calculates, for each of the plurality of MG torque candidate values, an engine supply fuel power, which is a power of a fuel that is supplied to the engine

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11104325B2Hybrid-vehicle controller

Publication Date: 2021.08.31 MITSUBISHI ELECTRIC MOBILITY CORP

AI summary

There is provided a hybrid-vehicle controller that can calculate MG demand torque with which fuel consumption in an engine can efficiently be decreased by increasing the MG's power-running torque. In the hybrid-vehicle controller, from a plurality of MG torque candidate values, there are selected the MG torque candidate values that make a 0 MG-torque-reference total supply power variation amount become the same as or smaller than a power-running-side variation amount upper limit value; then, there is selected, as a power-running-side final MG torque candidate value, the MG torque candidate value that makes an absolute value of the relative supply power variation amount ratio become maximum, among the selected MG torque candidate values.