Variable Neutral Point Torque Control for Hybrid Vehicle Mode Transitions

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Solution Overview

Problem

Hybrid motor vehicles experience discomfort during transitions between hybrid and electric modes due to sudden braking and differing deceleration sensations, especially when clutching and declutching, and existing control methods do not account for coupling and decoupling of electric and heat engines.

Innovation Solution

A method that divides the accelerator pedal stroke into a variable neutral point position for a first braking-adjustment stroke and a second acceleration-adjustment stroke, determining regenerative braking torque based on pedal depression and vehicle speed, with functions stored in memory to manage torque transitions smoothly between hybrid and electric modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If regenerative braking is controlled during deceleration phases without braking, then energy recovery is maximized, but sudden braking occurs during mode transitions causing passenger discomfort

Engineering Contradiction:

Improveenergy recoveryVSAvoidpassenger discomfort

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the neutral point position variable rather than fixed. The neutral point adapts dynamically based on vehicle speed and mode of operation (hybrid vs electric), allowing the regenerative braking control to adjust smoothly during transitions. This dynamic adjustment prevents sudden braking sensations while maintaining energy recovery efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of neutral point position along the accelerator pedal stroke based on vehicle conditions. By modifying this parameter according to speed and mode, the system optimizes the division between braking-adjustment and acceleration-adjustment strokes, ensuring smooth transitions and comfortable deceleration while maximizing regenerative energy recovery.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the accelerator pedal stroke is divided at a fixed neutral point, then control is simplified, but deceleration sensations differ between hybrid and electric modes reducing comfort

Engineering Contradiction:

Improvecontrol complexityVSAvoiddeceleration sensation difference

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The neutral point position is made dynamic and adaptive rather than fixed. It varies according to vehicle speed and operating mode (hybrid or electric), allowing the control system to maintain consistent deceleration characteristics across different modes while still providing a relatively simple control architecture.

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If regenerative braking torque is maximized during mode transitions, then energy recovery is optimized, but abrupt torque changes occur causing discomfort

Engineering Contradiction:

Improveenergy recoveryVSAvoidpassenger comfort

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

The system performs preliminary adjustment of the neutral point position before mode transitions occur. By anticipating the transition and pre-adjusting the division point between braking and acceleration strokes, the system prepares the regenerative braking torque to change smoothly, preventing abrupt torque changes while maintaining optimal energy recovery.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The regenerative braking torque is controlled dynamically through the variable neutral point, allowing smooth adaptation during mode transitions rather than abrupt changes. This dynamic control maintains both energy recovery efficiency and passenger comfort.

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 provides progressive resistive torque during mode transitions, enhances passenger comfort by maintaining identical deceleration sensations in both modes, and maximizes energy recovery by allowing driver-proportioned regenerative braking.

Implementation Method 1

the electric motor then works as a generator and converts the mechanical energy applied to its rotor into an electrical current

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10166970B2Control of torque transmitted to the driving wheel of a hybrid motor vehicle

Publication Date: 2019.01.01 HORSE POWERTRAIN SOLUTIONS S L U

AI summary

A method for controlling a mechanical torque transmitted to a driving wheel of a hybrid motor vehicle includes dividing a stroke of a vehicle acceleration pedal at a variable neutral point position into a first braking-adjustment stroke and a second acceleration-adjustment stroke, determining, within the first braking-adjustment stroke in which an electric motor of the vehicle operates as a generator, a regenerative braking torque setpoint for the electric motor based on a depression of the accelerator pedal and based on of a value of maximum energy recovery torque established based on a first function stored in a memory, and providing a value of maximum recovery torque depending on a vehicle speed. The first function assumes a value of substantially zero for an upper limit speed corresponding to the vehicle speed at the moment of coupling and decoupling of the electric motor by a connection device of the vehicle.