Hybrid Drive Torque Monitoring via Normalized Control

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Solution Overview

Problem

Existing torque monitoring systems for hybrid drives face challenges in efficiently extending torque monitoring from internal combustion engines to hybrid drives without requiring significant modifications to existing software and maintaining accurate torque comparisons within the same value range as pure internal combustion engines.

Innovation Solution

The method involves forming the permissible torque of the internal combustion engine by subtracting the actual torque of the electric drive from the total permissible torque, allowing for normalized torque calculations and minimizing changes to engine control programs, thus enabling seamless integration and memory-efficient storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If torque monitoring is extended from internal combustion engines to hybrid drives, then monitoring capability is improved, but software complexity and modification requirements increase

Engineering Contradiction:
Improvetorque monitoring capabilityVSAvoidsoftware complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The torque monitoring function is segmented into separate evaluation paths: one for internal combustion engine torque and another for electric drive torque. The control unit independently evaluates each torque source against its respective permissible values, then combines the results to determine overall torque status. This segmentation allows existing ICE monitoring software to remain unchanged while adding hybrid drive monitoring capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control unit is designed with multi-functionality to handle both internal combustion engine torque monitoring and electric drive torque monitoring within a single system. The same control unit evaluates permissible torque values, actual torque values, and comparison logic for both power sources, enabling a universal monitoring solution that works for both drive types without requiring separate dedicated monitoring systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Quantity of substance

If normalized torque calculations are used, then storage space and calculation time are reduced, but accurate torque comparisons across hybrid drive components become more challenging

Engineering Contradiction:
Improvestorage spaceVSAvoidtorque comparison accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The system changes the parameter representation of torque values by using normalized torque values (as percentages of maximum permissible torque) instead of absolute torque values. This parameter transformation reduces storage requirements and simplifies calculations while maintaining comparison accuracy because the normalized values preserve the relative relationships between torque demands and permissible limits for both ICE and electric drive components.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1981728B1Monitoring system for a hybrid drive
Publication Date: 2016.09.28 ROBERT BOSCH GMBH
  • EP1981728B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for the continuous torque monitoring of a hybrid drive composed of an internal combustion engine with an engine control unit and an inherently safe electric drive with a control unit, wherein a permissible total torque is compared with the sum of an actual torque of the electric drive and an actual torque of the internal combustion engine. If the permissible total torque is reduced by the actual torque of the electric motor and is formed by a permissible torque of the internal combustion engine, it is largely possible by means of this method for existing software to be utilized further, and said software need not be amended. In the engine controller, it is largely possible for calculations to be carried out with torques which are normalized to the maximum torque of the internal combustion engine. In the comparison stage in particular, the value range of the torques in the case of a hybrid drive in relation to that in the case of a pure internal combustion engine is maintained. Storage-space-saving and calculation-duration-saving programming is therefore possible.