Hybrid Engine Combustion Diagnostics Threshold Control

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Solution Overview

Problem

Conventional strategies for detecting combustion irregularities in hybrid vehicles with both combustion and electric engines are ineffective due to the electric engine compensating for combustion engine malfunctions, masking anomalies such as misfires.

Innovation Solution

A method that determines a threshold value for the electric engine's power percentage to prevent falsification of diagnostic results, reduces electric engine power during diagnostics to ensure reliable detection of combustion irregularities, and re-establishes a nominal hybrid operating mode post-diagnosis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the electric engine operates at high power percentage to improve hybrid vehicle efficiency and reduce emissions, then energy consumption is reduced, but combustion irregularity detection becomes unreliable due to compensation of combustion engine malfunctions

Engineering Contradiction:

Improveenergy consumptionVSAvoidcombustion irregularity detection accuracy

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The system performs preliminary assessment of electric engine power percentage before initiating combustion diagnostics. When the electric engine power percentage exceeds a predetermined threshold, the system delays or cancels the diagnostic procedure, preventing false negative results. This preliminary check ensures that diagnostics are only performed when combustion engine contributions are sufficient for reliable detection.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The diagnostic strategy dynamically adapts based on real-time hybrid operating conditions. The system continuously monitors the electric engine power percentage and adjusts diagnostic execution accordingly - performing diagnostics when combustion engine power is dominant (low electric power percentage) and suppressing them when electric engine compensation would mask irregularities (high electric power percentage).

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If the electric engine power is reduced during diagnostics to improve detection reliability, then combustion irregularity detection accuracy improves, but hybrid vehicle efficiency decreases and pollutant emissions increase

Engineering Contradiction:

Improvecombustion irregularity detection accuracyVSAvoidpollutant emissions

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

Instead of completely disabling the electric engine or forcing it to zero power during diagnostics, the system applies partial action by only suppressing diagnostics when electric power percentage exceeds the threshold. The electric engine continues to operate at its optimal power level, providing both propulsion and emission reduction benefits, while diagnostics are simply postponed to appropriate moments when combustion engine power is sufficient for reliable detection.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system maintains continuous useful action by keeping the electric engine operating at its optimal power percentage throughout all driving conditions. Rather than interrupting or reducing electric engine operation for diagnostics, the system continuously provides propulsion and emission reduction benefits, performing combustion diagnostics only during periods when combustion engine power naturally dominates.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If combustion diagnostics are performed continuously to improve reliability of malfunction detection, then detection coverage increases, but false negative results increase due to electric engine compensation

Engineering Contradiction:

Improvemalfunction detection coverageVSAvoiddetection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system implements periodic combustion diagnostics with conditional execution based on hybrid operating mode assessment. Rather than continuous diagnostics that would produce false negatives during electric-dominant operation, the system periodically evaluates whether current conditions are suitable for accurate detection (by checking electric power percentage threshold) and only executes diagnostics when conditions are favorable, ensuring both coverage and accuracy.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10864815B2Method for detecting combustion irregularities of an internal combustion engine unit coupled to an electric propulsion unit, of a hybrid motor vehicle

Publication Date: 2020.12.15 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

A method for detecting combustion irregularities in a combustion engine coupled to an electric engine of a hybrid vehicle having a management unit for determining the respective powers to be supplied by these engines, and for delivering setpoint data dependent on these power distributions, including determining a threshold value corresponding to a percentage of the power supplied by the electric engine, such that values of this percentage less than or equal to the threshold value correspond to operation of the electric engine that is not liable to falsify the results of the combustion irregularity detection diagnostics, and, for the purpose of launching a diagnostic procedure, when the percentage of the power supplied by the electric engine is greater than the threshold value, delivering setpoint data suitable for fixing the value of the power percentage at a setpoint value less than the threshold.