Fuel Injector Leak Detection via Oxygen Sensor Monitoring
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Solution Overview
Problem
Internal combustion engines face challenges in operating with a stoichiometric or lean air-fuel ratio during starting and run-up due to unintended fuel release from fuel injectors, leading to increased hydrocarbon emissions and excessive emissions levels.
Innovation Solution
A method involving an engine control system that identifies fuel injectors releasing fuel while commanded off by monitoring oxygen sensor output during cranking and run-up, adjusts actuators to isolate the affected cylinder, and repeatedly deactivates cylinders to determine the faulty injector, allowing for specific cylinder identification and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the engine is operated with stoichiometric or lean combustion before the after treatment system reaches operating temperature, then tailpipe emissions of hydrocarbons and carbon monoxide are reduced, but it is difficult to maintain the desired air-fuel ratio due to unintended fuel release from fuel injectors
Solution Approach 1:
The system performs preliminary diagnosis of fuel injectors before engine operation by detecting fuel leakage during a closed state. This preliminary detection allows the ECU to identify and compensate for leaking injectors before they affect air-fuel ratio control during stoichiometric or lean combustion, enabling reliable low-emission operation.
Solution Approach 2:
The system uses oxygen sensors to continuously monitor the air-fuel ratio during engine operation and provides feedback to the ECU. This feedback loop allows the system to detect deviations caused by fuel injector leakage and adjust fuel injection quantities to maintain the desired air-fuel ratio for reduced emissions.
2Object-generated harmful factors
If fuel is released from a fuel injector while the fuel injector is not being commanded open, then the released fuel increases engine hydrocarbon emissions, but detecting the specific leaking injector becomes complex
Solution Approach 1:
The diagnostic system segments the fuel injection system by individually testing each fuel injector during a closed state. By isolating and testing injectors one at a time, the system can identify the specific leaking injector without requiring complex multi-injector diagnostic logic, thereby reducing overall system complexity while effectively reducing hydrocarbon emissions.
Solution Approach 2:
The system introduces an intermediary diagnostic mode where fuel injectors are tested in a controlled closed state separate from normal operation. This intermediary testing phase allows detection of fuel leakage without affecting engine operation, simplifying the diagnostic process while reducing hydrocarbon emissions from leaking injectors.
3Measurement precision
If the oxygen sensor is used to determine fuel release during cranking and run-up, then the fuel injector leak can be identified, but the oxygen sensor must reach operating temperature first
Solution Approach 1:
The system performs fuel injector diagnosis during the oxygen sensor warm-up period before the sensor reaches operating temperature. By utilizing this otherwise idle time for preliminary diagnostic testing, the system avoids delaying engine operation while still achieving precise fuel-air ratio measurement once the sensor is ready, effectively eliminating time loss.
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 reduces engine emissions, identifies and addresses fuel injector leaks, and minimizes fuel consumption by optimizing engine starting procedures and cylinder operation.
Implementation Method 1
a fuel-air ratio indicated from an oxygen sensor during engine cranking and run-up
Data Source
AI summary
Methods and systems for evaluating whether or not a fuel amount that is greater than a threshold has been release to an engine via fuel injectors when the fuel injectors are commanded off are presented. In one example, an oxygen sensor is activated and engine cranking is prevented until a pumping current of the oxygen sensor is proportionate to a concentration of oxygen sensed via the oxygen sensor so that released fuel may be observed during engine starting.