Hybrid Drive Torque Compensation During Engine Reactivation

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Solution Overview

Problem

The technical challenge is to enable efficient and comfortable transition from drag-torque-reduced, unfired operation to fired operation of the combustion motor in a hybrid drive, while minimizing discomfort to the user and maintaining energy efficiency.

Innovation Solution

A control unit for a hybrid drive is configured to manage the transition from drag-torque-reduced, unfired operation to fired operation by ending drag-torque-reducing measures and compensating the increased drag torque with the electric machine, ensuring a continuous and comfortable torque variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drag-torque-reducing measures are ended to enable fired operation of the combustion motor, then the combustion motor can be reactivated, but the increased drag torque causes discomfort to the user

Engineering Contradiction:

Improvecombustion motor reactivationVSAvoiduser comfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The electric machine is operated in advance to compensate for the upcoming increase in drag torque when drag-torque-reducing measures are ended. This preliminary action ensures that the overall torque remains continuous and prevents perceptible torque drops that would cause user discomfort during the transition to fired operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The electric machine acts as an intermediary between the combustion motor and the drivetrain during the transition phase. It compensates for the torque fluctuations caused by ending drag-torque-reducing measures, smoothing out the overall torque delivery and maintaining user comfort while enabling combustion motor reactivation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If drag-torque-reducing measures are active during unfired operation, then energy efficiency is improved, but the combustion motor cannot be reactivated

Engineering Contradiction:

Improvecranking energy efficiencyVSAvoidcombustion motor reactivation capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The system dynamically adjusts the drag torque characteristics by controlling the ending of drag-torque-reducing measures at an optimal moment. The electric machine provides compensatory torque during the transition, enabling the combustion motor to be reactivated from a low-drag state without sacrificing reactivation capability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control unit changes the operational parameters of the electric machine during the transition phase, increasing its torque output to compensate for the increased drag torque when drag-torque-reducing measures are ended. This parameter change enables seamless transition from unfired to fired operation.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the electric machine compensates for increased drag torque, then overall torque remains continuous, but the electric machine must be operated at higher torque levels

Engineering Contradiction:

Improveoverall torque continuityVSAvoidelectric machine torque output

Core Design Contradiction:

Stability of the object's compositionVSPower

Solution Approach 1:

The electric machine provides compensatory torque in a periodic manner during the transition phase, activating when drag-torque-reducing measures are ended and deactivating once the combustion motor is reactivated. This periodic action maintains overall torque continuity while limiting the duration of high electric machine torque output.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12221933B2Control unit and method for operating a hybrid drive having an internal combustion engine with reduced drag torque

Publication Date: 2025.02.11 BAYERISCHE MOTOREN WERKE AG

AI summary

A control unit is provided for a hybrid drive that includes an internal combustion engine and an electric machine. The control unit is configured to cause one or more drag torque reduction measures of the internal combustion engine to be terminated in preparation for firing the internal combustion engine. In addition, the control unit is configured to cause the electric machine to at least partly compensate for an increase in the drag torque of the internal combustion engine caused by the termination of the one or more drag torque reduction measures.