Rotational Fluctuation Detection in Idle Stop Engines
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Solution Overview
Problem
Existing rotational fluctuation malfunction detection systems in internal combustion engines face challenges in accurately determining malfunctions due to the rarity of non-disturbance fluctuation states in vehicles equipped with idle stop functions, leading to potential misdiagnosis of rotational speed fluctuations caused by vehicle system malfunctions.
Innovation Solution
A rotational fluctuation malfunction detection device and method that includes a parameter obtaining device, an automatic engine stop device, and a signal output device, which differentiate between disturbance and non-disturbance fluctuation states by using fluctuation parameters to determine abnormality in rotational speed uniformity, ensuring precise detection of malfunctions even in vehicles with limited non-disturbance state opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the vehicle is equipped with an idle stop function that stops the internal combustion engine under predetermined conditions, then fuel efficiency is improved, but the opportunity to obtain fluctuation parameters in non-disturbance states becomes rare
Solution Approach 1:
The system pre-accumulates fluctuation parameters during disturbance fluctuation states when the engine is running. This preliminary data collection ensures that sufficient parameters are stored before a non-disturbance state occurs, allowing malfunction detection to proceed without waiting for rare idle stop conditions.
Solution Approach 2:
The system dynamically switches between two operational modes: accumulating fluctuation parameters during disturbance states and performing malfunction determination during non-disturbance states. This dynamic adaptation allows the system to optimize both fuel efficiency (by enabling idle stops) and detection accuracy (by ensuring sufficient data availability).
2Productivity
If fluctuation parameters are obtained in disturbance fluctuation states, then detection opportunities increase, but misdiagnosis of rotational speed fluctuations may occur
Solution Approach 1:
The system segments the detection process into two distinct phases: a data accumulation phase during disturbance fluctuation states and a determination phase during non-disturbance states. This segmentation allows the system to collect sufficient data when opportunities arise while ensuring final judgments are made under optimal conditions without disturbance interference.
Solution Approach 2:
The control unit acts as an intermediary that stores fluctuation parameters obtained during disturbance states and retains them for later analysis during non-disturbance states. This intermediary storage mechanism decouples the data collection process from the decision-making process, allowing each to occur under their respective optimal conditions.
Data Source
AI summary
A rotational fluctuation malfunction detection device for an internal combustion engine determines that fluctuations in output shaft rotational speed are “normal” when a rotational fluctuation value, obtained in a “disturbance fluctuation state” is below threshold L1. If rotational fluctuation value obtained in “disturbance fluctuation state” equals or exceeds L2, the rotational fluctuation malfunction detection device determines that the rotational fluctuation value is “abnormal.” However, when the rotational fluctuation value obtained in “disturbance fluctuation state” is equal to L1 or between L1 and L2, the rotational fluctuation malfunction detection device determines that the rotational fluctuation value is “normal” if the rotational fluctuation value obtained in the “non-disturbance state” is below L3, and the rotational fluctuation value is “abnormal” if the rotational fluctuation value obtained in the “non-disturbance state” equals or exceeds L3.