Misfire Detection in Engines with Torsional Dampers
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Solution Overview
Problem
Conventional misfire determination methods for internal combustion engines connected via torsional elements, such as dampers, face difficulties in accurately determining misfires due to resonance and torque fluctuations, making reliable detection challenging.
Innovation Solution
An internal combustion engine system that includes a rotation regulating module, a rotational position detecting module, a rotation fluctuation calculating module, an influence component calculating module, and a misfire determining module, which calculates and considers the influence component on rotation fluctuation to accurately determine misfires by subtracting the calculated influence from the rotation fluctuation, thereby enhancing detection reliability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If vibration control by motor is conducted, then torque fluctuation is suppressed, but misfire determination becomes difficult
Solution Approach 1:
The patent extracts the harmful influence of vibration control torque from the rotation fluctuation signal by calculating an influence component based on the transfer function and subtracting it, thereby isolating the misfire-related rotation fluctuation for accurate determination
Solution Approach 2:
The patent introduces a transfer function as an intermediary mathematical model that describes the relationship between motor torque and engine rotation fluctuation, enabling the calculation and removal of vibration control influence from the measured signal
2Stability of the object's composition
If engine is connected via torsional element such as damper, then torque fluctuation is suppressed, but entire transmission resonates and misfire determination becomes difficult
Solution Approach 1:
The patent extracts the resonance influence from the rotation fluctuation signal by calculating an influence component that accounts for torsional element dynamics and subtracting it, thereby isolating the misfire-related components for accurate determination
Solution Approach 2:
The patent introduces a transfer function as an intermediary that models the complex interaction between engine, torsional element, and transmission, enabling the calculation and removal of resonance effects from the measured rotation fluctuation signal
3Device complexity
If conventional misfire determination method is used, then system complexity is low, but determination reliability is insufficient under resonance conditions
Solution Approach 1:
The patent introduces a transfer function as an intermediary mathematical model that enables reliable misfire determination under resonance conditions by accounting for the dynamic interaction between engine, torsional element, and transmission without requiring complex hardware modifications
Solution Approach 2:
The patent changes the approach from direct signal analysis to frequency-domain analysis using transfer functions, transforming the problem into calculating and removing influence components based on the relationship between motor torque and engine rotation fluctuation across different frequencies
Data Source
AI summary
An influence component N30m of every 30 degrees in a 30 degree rotation speed N30 base as time required for 30 degree rotation of a crankshaft is calculated by using a frequency characteristic of an influence given to a rotation fluctuation of a crankshaft by output torque output from a motor, which is calculated by using a mechanical model and an amplitude P and a phase q at a time of vibration control by the motor, a determination duration T30j is calculated by subtracting an influence component T30m as an inverse number of this from 30 degree duration T30, and misfire of an engine is determined by comparing the calculated determination duration T30j with a threshold value Tref. Thereby, misfire of the engine outputting power to a post-stage via a damper can be determined more reliably and accurately.