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Methods and systems for identification and mitigation of air-fuel ratio imbalances

An air-fuel ratio and balance technology, applied in the field of engine cylinders, can solve the problems of aggravating the exhaust flow in the partition, failing to successfully alleviate the imbalance, and unable to detect the exhaust gas concentration equally, so as to simplify the detection, mitigation and reduction of the cylinder. unbalanced effect

Active Publication Date: 2021-10-26
FORD GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Various faults such as an air-fuel ratio imbalance between cylinders can exacerbate this uneven, zoned exhaust flow condition such that neither the pre-catalyst sensor nor the post-catalyst sensor can equally detect the concentration of exhaust gas from all cylinders
Therefore, the air-fuel ratio control implemented in U.S.8695568B2 was not successful in alleviating the imbalance

Method used

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  • Methods and systems for identification and mitigation of air-fuel ratio imbalances
  • Methods and systems for identification and mitigation of air-fuel ratio imbalances
  • Methods and systems for identification and mitigation of air-fuel ratio imbalances

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Embodiment Construction

[0013] The following description relates to systems and methods for detecting and mitigating cylinder-to-cylinder imbalance. The systems and methods can be used in vehicles such as figure 1 is implemented in the vehicle system depicted in ). as in figure 2 As shown in , a vehicle may include a multi-cylinder engine system and an exhaust aftertreatment system. If one of the cylinders has a fault that creates an air-fuel imbalance, the exhaust composition may be non-uniform across the cross-section of the exhaust tract, and a single exhaust oxygen sensor cannot detect the imbalance. To detect and mitigate air-fuel ratio imbalances when the imbalance fault is minor, pre-catalyst and post-catalyst sensors coupled to the exhaust passages are used in the engine system. due to figure 2 The partitioned exhaust flow shown in , the pre-catalyst sensor and the post-catalyst sensor have different sensitivities to the air-fuel ratio of each engine cylinder. Using different sensitivi...

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Abstract

The present invention relates to methods and systems for the identification and mitigation of air-fuel ratio imbalances. Methods and systems for identifying unbalanced cylinders and mitigating unbalanced cylinders are provided. In one example, a method may include identifying an unbalanced cylinder based on readings from two exhaust gas oxygen sensors positioned upstream and downstream of a catalyst in an exhaust passage, and mitigating the cylinder based on a magnitude of the failure determined from the readings. unbalanced.

Description

technical field [0001] The present invention generally relates to methods and systems for identifying unbalanced engine cylinders and mitigating the unbalance. Background technique [0002] Modern vehicles use a three-way catalyst (TWC) for exhaust aftertreatment of gasoline engines. Due to tightening government regulations on motor vehicle emissions, the air-fuel ratio of each engine cylinder in a multi-cylinder engine is closely monitored. Ideally, each engine cylinder should be designed with an exhaust gas composition sensor for accurately measuring the cylinder's air-fuel ratio. In practice, however, due to affordability constraints, exhaust oxygen sensors disposed upstream and downstream of the TWC may be used to control the air-fuel ratio near the stoichiometric ratio. [0003] Other attempts to address cylinder imbalances include detecting and mitigating air-fuel ratio imbalances based on pre-catalyst and post-catalyst sensors. An example method is shown by Yoshika...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F02D41/00F02D41/14F02D41/30
CPCF02D41/0085F02D41/1441F02D41/1454F02D41/1498F02D41/30F02D41/1439F02D41/1456
Inventor M·J·于里克M·A·桑蒂洛R·D·普斯弗
Owner FORD GLOBAL TECH LLC