Differential Pressure Sensor Abnormality Detection in EGR Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining abnormality in differential pressure sensors used in EGR systems face accuracy issues due to exhaust pulsation, which affects fuel efficiency and controllability, and current solutions either compromise accuracy or fuel efficiency.
Innovation Solution
A method and system that control the EGR valve and throttle valve to maintain a pressure differential of at least 5 kPa between the upstream and downstream sides of the EGR valve during abnormality determination, while restricting such determinations to low engine speeds to minimize pulsation influence, ensuring accurate sensor assessment without deteriorating fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the throttle valve is controlled toward the closed side to increase pressure differential for abnormality determination, then the accuracy of differential pressure sensor abnormality determination is improved, but fuel efficiency deteriorates due to increased boosting pressure
Solution Approach 1:
The patent applies partial action by controlling the throttle valve toward the closed side only to the extent necessary to generate the minimum required pressure differential (5 kPa or more) for accurate sensor abnormality determination, rather than fully closing it. This partial control achieves the measurement accuracy goal while minimizing the negative impact on fuel efficiency and engine performance.
2Measurement precision
If abnormality determination is performed only when pressure differential is large, then the accuracy of determination is improved, but the frequency of performing abnormality determination decreases
Solution Approach 1:
The patent applies preliminary action by proactively controlling the throttle valve to generate the required pressure differential (5 kPa or more) before performing the abnormality determination, rather than waiting for such conditions to occur naturally. This ensures the necessary measurement conditions are established in advance, enabling frequent and accurate abnormality checks without relying on rare natural occurrences of high pressure differential.
3Measurement precision
If a large pressure differential is generated between upstream and downstream sides of EGR valve, then the influence of exhaust pulsation is reduced, but the deterioration in fuel efficiency increases
Solution Approach 1:
The patent converts the harmful effect of exhaust pulsation into a beneficial condition by utilizing the pressure differential generation mechanism. By controlling the throttle valve to create a pressure differential of 5 kPa or more, the pulsation noise is suppressed and converted into a stable measurement condition, turning what was originally a source of measurement error into a means of achieving both accurate measurement and acceptable fuel efficiency.
Data Source
AI summary
A method of determining an abnormality of a differential pressure sensor which is configured to detect a pressure differential between an upstream side and a downstream side of an EGR valve provided to an EGR passage of an engine, is provided. The method includes the steps of controlling an opening of the EGR valve based on an output value of the differential pressure sensor, determining the abnormality of the differential pressure sensor based on the output value of the differential pressure sensor, controlling at least a throttle valve of the engine toward a closed side so that the pressure differential is maintained at a given pressure or higher when determining, and prohibiting the execution of the abnormality determination when an engine speed is a given engine speed or higher, and permitting the execution of the abnormality determination when the engine speed is less than the given engine speed.