Hybrid Vehicle Engine Malfunction Detection Control
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Solution Overview
Problem
In plug-in hybrid vehicles, the low frequency of engine operation during the charge depleting mode can delay the detection of engine malfunctions, leading to potential deterioration in fuel economy and emission properties, as the number of engine rotations may not reach a reference number required for timely malfunction determination.
Innovation Solution
A control apparatus with an electronic control unit that determines engine malfunctions by tracking abnormal combustion events in both charge sustaining and charge depleting modes, using a cumulative count of abnormal combustion occurrences during the charge depleting mode to ensure early detection, and resetting counts when a predetermined number of engine rotations is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine operates only in charge depleting mode with low frequency, then battery charge is maintained, but engine malfunction detection is delayed
Solution Approach 1:
The system performs preliminary accumulation of abnormal combustion events during the charge depleting mode when engine operation frequency is low. By storing these events and continuing to monitor them, the system prepares detection data in advance so that when the engine reaches the reference rotation number, malfunction detection can be performed immediately without delay, resolving the contradiction between low operation frequency and timely detection.
2Reliability
If idle-up control is performed to accelerate malfunction detection, then detection speed improves, but fuel economy deteriorates
Solution Approach 1:
The system uses feedback by continuously monitoring and accumulating abnormal combustion events across multiple operating cycles. Instead of forcing idle-up to accelerate detection, the system feeds back the accumulated event data and performs detection as soon as the reference rotation number is reached under normal operating conditions, thereby maintaining fuel economy while achieving timely malfunction detection through intelligent data accumulation and threshold-based triggering.
3Measurement precision
If the reference rotation number is set high for accurate detection, then detection accuracy improves, but detection time increases
Solution Approach 1:
The system merges abnormal combustion events that occur across multiple separate engine operations into a cumulative total. By combining these scattered events and comparing the accumulated sum against the reference rotation number, the system achieves both high detection accuracy (through sufficient sample size) and reduced detection time (by utilizing all available operations rather than requiring a single long observation period).
Data Source
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AI summary
A vehicle includes an engine, a motor, a battery that stores an electric power for driving the motor, and a control apparatus. The control apparatus is configured to control the engine and the motor in one of control modes, the control mode includes a charge sustaining (CS) mode and a charge depleting (CD) mode. During the CS mode, a first determination is made to determine that the engine malfunction has occurred when a number of times of abnormal combustion occurring during a current trip is equal to or larger than a threshold. During the CD mode, instead of or in addition to the first determination, a second determination is made to determine that the engine malfunction has occurred when a cumulative number of times of abnormal combustion is equal to or larger than the threshold.