Engine Diagnosis Using Diagnostic Gear to Exclude Oscillation
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Solution Overview
Problem
Conventional internal combustion engine diagnosis methods using running irregularity signals are inaccurate due to low-frequency oscillation effects from certain transmission ratios, leading to false fault classifications and unauthorized fault entries in the engine control unit.
Innovation Solution
A method and device that utilize a diagnostic gear of the transmission unit to ascertain a diagnostic value, compare it with predefined thresholds, and verify the engaged gear against predefined gears to ensure a reliable diagnosis, excluding low-frequency oscillation effects by potentially changing gears for re-evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional signal filtering is used to eliminate high-frequency disturbance variables, then high-frequency noise is removed, but low-frequency oscillation effects from certain transmission ratios remain and cause diagnostic inaccuracy
Solution Approach 1:
The system dynamically adapts the diagnostic procedure by detecting the current transmission ratio and adjusting the diagnostic approach accordingly. When a problematic transmission ratio is detected, the system switches to an alternative diagnostic method or requests a gear change, making the diagnostic process flexible and adaptive to changing operating conditions rather than using a static filtering approach
Solution Approach 2:
The system changes the operating parameter (transmission ratio/gear) to eliminate the harmful low-frequency oscillation effects. By detecting when a problematic gear ratio is engaged and requesting a gear change through the transmission control unit, the system transforms the diagnostic conditions to achieve accurate measurements free from oscillation interference
2Reliability
If the diagnostic procedure is continuously performed, then cylinder diagnosis is maintained, but false fault entries occur due to low-frequency oscillation effects from certain transmission ratios
Solution Approach 1:
The system implements a feedback mechanism where the current transmission ratio is continuously monitored during diagnosis. When a problematic ratio is detected, the system receives feedback from the transmission control unit about the engaged gear and initiates corrective action by requesting a gear change, creating a closed-loop control system that prevents false diagnostics
Solution Approach 2:
The system performs preliminary detection of the transmission ratio before completing the diagnostic evaluation. By detecting potentially problematic gear ratios in advance and requesting gear changes before false fault entries are generated, the system prevents harmful outcomes rather than correcting them after they occur
3Measurement precision
If the transmission ratio is changed to avoid low-frequency oscillation effects, then diagnostic accuracy is improved, but additional time is required for gear changes and re-evaluation
Solution Approach 1:
The system applies partial action by selectively requesting gear changes only when problematic transmission ratios are detected, rather than changing gears for every diagnostic cycle. This targeted approach minimizes unnecessary gear changes and time loss while still preventing false fault entries when needed
Data Source
AI summary
The disclosure relates to a method and a device for diagnosing an internal combustion engine of a powertrain. The powertrain includes the internal combustion engine and a transmission unit, and the diagnosis is carried out using a running irregularity signal, where potentially a gear change is actively requested. The method includes ascertaining a diagnostic value of the internal combustion engine during operation using the running irregularity signal of the internal combustion engine. The powertrain is operated using a diagnostic gear of the transmission unit. The method also includes detecting the diagnostic gear which is engaged in the transmission unit while ascertaining the diagnostic value; and comparing the ascertained diagnostic value with a predefined diagnostic threshold value and comparing the diagnostic gear of the transmission unit with at least one predefined gear of the transmission unit.