Pre-chamber Air Fuel Offset Diagnosis via Exhaust Gas Oxygen
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Solution Overview
Problem
Current methods fail to accurately diagnose and correct air and fuel injection offsets in pre-chambers of internal combustion engines, leading to pre-chamber misfires and increased engine repair times and costs due to the inability to distinguish between pre-chamber and cylinder misfires.
Innovation Solution
A method involving adjusting air and fuel injection amounts in the pre-chamber based on offsets learned during a fuel-cut event with reduced engine airflow, using exhaust gas measurements to identify and correct air and fuel injection errors, thereby improving the accuracy of pre-chamber injections and reducing misfires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If pre-chamber ignition is used to improve engine performance and fuel economy, then power output and efficiency increase, but pre-chamber misfire frequency increases due to inaccurate air and fuel injection
Solution Approach 1:
The system performs preliminary diagnosis of air and fuel injection offsets before normal operation by conducting tests during fuel-cut events. The controller learns the actual injection amounts by comparing commanded versus actual air-fuel ratios, and adjusts injection parameters in advance to compensate for identified offsets, thereby preventing misfires during normal engine operation
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors exhaust gas oxygen levels and compares actual air-fuel ratio measurements against commanded values. Based on the detected offsets, the controller automatically adjusts air and fuel injection amounts to maintain accurate mixing, ensuring reliable pre-chamber ignition while maintaining improved power output
2Reliability
If current misfire detection methods are used, then misfires are detected, but the source of misfire cannot be distinguished between pre-chamber and cylinder
Solution Approach 1:
The system segments the misfire diagnosis process into distinct phases: during fuel-cut events, the controller independently tests the pre-chamber injection system by introducing only air and measuring oxygen levels in exhaust gases. This separate testing approach isolates pre-chamber performance from cylinder combustion, enabling identification of whether misfires originate from pre-chamber or cylinder issues
Solution Approach 2:
The system uses exhaust gas oxygen measurements as an intermediary indicator to diagnose injection offsets. By measuring oxygen levels in exhaust gases during controlled fuel-cut events, the controller can infer the accuracy of air and fuel injection without direct sensors in the pre-chamber, thereby identifying misfire sources while avoiding complex additional hardware
3Reliability
If air and fuel injection offsets are not corrected, then pre-chamber misfire occurs, but repair time and costs increase due to inability to identify the problem source
Solution Approach 1:
The system performs self-diagnosis and self-correction of injection offsets automatically during normal operation. The controller conducts diagnostic tests during fuel-cut events, identifies air and fuel injection inaccuracies, and adjusts injection parameters without external intervention. This eliminates the need for manual troubleshooting and reduces repair time while maintaining reliable pre-chamber operation
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 pre-chamber and cylinder misfires, enhances engine performance, improves fuel economy, and decreases emissions by ensuring accurate air-fuel mixtures, thereby streamlining repair procedures and reducing customer costs.
Implementation Method 1
the spark plug in the pre-chamber actuates, igniting the first air-fuel mixture. As the first air-fuel mixture combusts, jets of flame and hot gas may exit the pre-chamber and enter the cylinder
Implementation Method 2
operated with a series of air-fuel ratio perturbations while a controller of the engine determined an actual air-fuel ratio during each perturbation based on an output from an exhaust gas oxygen sensor
Data Source
AI summary
Methods and systems are provided for a vehicle engine having a pre-chamber ignition system. In one example, a method may include adjusting one or more of an air injection amount and a fuel injection amount to a pre-chamber of an engine based on an air injection offset and a fuel injection offset learned while discontinuing fueling to cylinders of the engine and reducing air flow through the engine. In this way, air and fuel may be more accurately provided to the pre-chamber, thereby decreasing an occurrence of pre-chamber misfire.