Gas Sensor Signal Processor for Exhaust Pulsation
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Solution Overview
Problem
Existing gas sensors in internal combustion engines face challenges in balancing the reduction of sensor output variation caused by exhaust pulsation with maintaining responsiveness to actual gas concentration changes, particularly in detecting cylinder-specific air-fuel ratios.
Innovation Solution
A signal processor for gas sensors that includes a calculation unit for moderation operations, an evaluation unit to assess the impact of pressure variation on sensor outputs, and a change unit to dynamically adjust the moderation mode based on evaluated parameters such as gas atmosphere, engine speed, and exhaust pressure change rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a moving average process is performed on sensor outputs to reduce variation caused by exhaust pulsation, then the sensor output variation is reduced, but the responsiveness of the sensor output to actual gas concentration changes deteriorates
Solution Approach 1:
The patent applies dynamics by making the moderation operation adaptable rather than fixed. The control unit dynamically adjusts whether to perform moderation based on detected cylinder-specific air-fuel ratio characteristics. When large variations are detected indicating exhaust pulsation, moderation is applied to stabilize the output. When small variations are detected indicating actual gas concentration changes, moderation is withheld to preserve responsiveness. This dynamic adaptation resolves the contradiction between stability and response speed.
Solution Approach 2:
The patent changes the parameter of moderation application from a constant state to a variable state based on detected conditions. By monitoring the magnitude of sensor output variations and comparing against thresholds, the system adjusts the moderation parameter (whether to apply moving average) according to the actual operating conditions. This parameter change allows the system to optimize between stability and responsiveness in different operational contexts.
2Stability of the object's composition
If a moving average process is performed on sensor outputs to moderate variation, then the sensor output is moderated, but the detection of intrinsic sensor output and cylinder-specific air-fuel ratio is disabled or delayed
Solution Approach 1:
The system dynamically controls the application of moderation based on real-time analysis of sensor output variations. By detecting whether variations are caused by exhaust pulsation (large, periodic variations) or actual gas concentration changes (small, meaningful variations), the control unit selectively applies or withholds moderation. This dynamic control ensures that moderation is only applied when it benefits stability without compromising the detection of genuine gas concentration changes, thus preserving measurement precision for cylinder-specific air-fuel ratio detection.
Solution Approach 2:
The patent implements feedback by continuously monitoring the sensor output variations and using this information to control the moderation operation. The control unit detects the magnitude of variations, compares them against predetermined thresholds, and adjusts the moderation application accordingly. This feedback mechanism ensures that moderation is applied only when necessary (when exhaust pulsation causes large variations) and withheld when it would interfere with accurate cylinder-specific air-fuel ratio detection, thereby maintaining measurement precision.
Data Source
AI summary
The present invention provides, as one aspect, a signal processor for a gas sensor that is disposed in an exhaust passage of an internal combustion engine and senses concentration of a specific component in exhaust gas. The signal processor includes a calculation unit that performs moderation operation at every instant for a sensor output of the gas sensor, an evaluation unit that evaluates a degree of pressure variation impact on the sensor output caused in the exhaust passage, and a change unit that changes a mode of the moderation operation according to a result of the evaluation by the evaluation unit.