Hybrid Engine Control for Catalyst Degradation Detection
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Solution Overview
Problem
Conventional power output apparatuses during catalyst degradation detection either cause the driver to feel awkward due to continuous engine load or prolong detection time by automatically stopping the engine.
Innovation Solution
A power output apparatus that controls the internal combustion engine to operate under no load during catalyst degradation detection, using an oxygen concentration measurement unit to vary power demand and ensure efficient exhaust flow through the emission control catalyst, thereby accelerating degradation detection and preventing battery overcharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine continues load operation during catalyst degradation detection, then the detection can be performed, but the driver feels awkward and the battery may be overcharged
Solution Approach 1:
The engine load is dynamically adjusted during catalyst degradation detection. The control module varies the load applied to the engine while performing degradation detection, allowing the engine to operate at reduced or zero load during detection periods, thereby preventing driver discomfort and battery overcharge while maintaining detection capability
Solution Approach 2:
The operating parameters of the engine are changed during degradation detection. The control module modifies engine load parameters and operational characteristics temporarily during detection windows, enabling degradation detection to proceed without maintaining full load operation that would cause driver discomfort or battery overcharge
2Ease of operation
If the engine automatically stops during catalyst degradation detection, then driver comfort is maintained, but the detection time is extended
Solution Approach 1:
Catalyst degradation detection is performed periodically during brief intervals when the engine is naturally at low or zero load (such as during idle periods or transient states). This periodic detection approach maintains driver comfort by avoiding prolonged engine shutdowns while accumulating sufficient detection data over time
Solution Approach 2:
The control module identifies and utilizes pre-existing low-load periods in the engine operation schedule for performing degradation detection. By detecting during these natural idle or low-load windows, the system avoids extending detection time while maintaining driver comfort
3Productivity
If the engine operates under no load during catalyst degradation detection, then driver comfort is maintained and detection is accelerated, but power output is reduced
Solution Approach 1:
The engine load is dynamically adjusted during catalyst degradation detection. The control module varies the load applied to the engine while performing degradation detection, allowing the engine to operate at reduced or zero load during detection periods, thereby preventing driver discomfort and battery overcharge while maintaining detection capability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables high-speed catalyst degradation detection without discomforting the operator and protecting the accumulator unit from overcharge, improving detection efficiency and operational comfort.
Implementation Method 1
an oxygen concentration measurement unit that is provided downstream of the emission control catalyst and has an output varying with a variation in concentration of oxygen included in the treated exhaust after the catalytic conversion by the emission control catalyst
Data Source
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AI summary
The power output apparatus of the invention increases a tentative engine power demand Petmp required for an engine (step S180), during a catalyst degradation detection time (step S120: yes) when degradation detection of an emission control catalyst is performed according to a variation in output of an oxygen sensor provided downstream of the emission control catalyst. The smaller between an increased power demand Peu by increasing the tentative engine power demand Petmp and an upper limit of a chargeable range of a battery is set to an engine power demand Pe* of the engine (step S190). Upon satisfaction of an auto engine stop condition that the engine power demand Pe* decreases below a preset reference power Pref (step S200: no), the engine is controlled to be driven at idle (step S210).