Engine Air-Fuel Ratio Control via Dynamic Sensor Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling air-fuel ratios in internal combustion engines are inaccurate due to scavenging effects and sensor measurement errors, leading to reduced engine performance and increased emissions.
Innovation Solution
Adjusting fuel injection based on both upstream and downstream air-fuel ratios depending on scavenging conditions, with more-downstream ratios used during increased scavenging to improve accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If air-fuel ratio control is based on upstream sensor measurements, then emissions control is improved, but scavenging capability is reduced
Solution Approach 1:
The system dynamically switches between using upstream and downstream air-fuel ratio measurements based on detected scavenging conditions. When increased scavenging is detected, the system transitions to using downstream measurements, allowing the engine to maintain both emissions control and enhanced scavenging capability
2Object-generated harmful factors
If air-fuel ratio control is based on upstream sensor measurements, then emissions control is improved, but engine efficiency is reduced
Solution Approach 1:
The control system dynamically adapts its measurement strategy based on operating conditions. By switching to downstream measurements during increased scavenging, the system enables more efficient engine operation while maintaining emissions control through appropriate fuel injection adjustments
3Object-generated harmful factors
If air-fuel ratio control is based on upstream sensor measurements, then emissions control is improved, but measurement accuracy is reduced
Solution Approach 1:
The system dynamically selects the appropriate sensor measurement source based on detected scavenging conditions. During increased scavenging, it switches to downstream measurements that are not affected by pass-through air, thereby maintaining measurement accuracy while still controlling emissions
Solution Approach 2:
The downstream air-fuel ratio sensor acts as an intermediary measurement point that provides accurate readings during scavenging conditions. By using this intermediate measurement location, the system obtains reliable air-fuel ratio data without being affected by the measurement errors that occur at upstream locations during scavenging
Data Source
AI summary
Methods and systems are provided for accurately measuring an air-fuel-ratio of an engine. During a first condition of decreased scavenging, adjusting fuel injection based on a more-upstream air-fuel ratio, and during a second condition of increased scavenging, adjusting fuel injection based on one or more more-downstream air-fuel ratios and not based on the more-upstream air-fuel ratio. During the first condition, adjusting fuel injection may be further based on the one or more more-downstream air-fuel ratios.