Engine Control Device EGR Diagnosis Timing
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Solution Overview
Problem
The diagnostic accuracy of an exhaust gas cleaning filter for fine particulate matter is compromised when simultaneously diagnosing its fracture and an exhaust gas recirculation device abnormality, as changes in the EGR valve position affect the exhaust gas state flowing into the filter.
Innovation Solution
An engine control device that separates the diagnosis processes for the exhaust gas recirculation device and the exhaust gas cleaning filter, executing them at different conditions to prevent accuracy reduction, using intake air pressure changes for the first diagnosis and temperature differences for the second diagnosis during fuel cut-off control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the abnormality diagnosis of the EGR device and the diagnosis of whether the exhaust gas cleaning filter has a fracture are performed at the same time, then the diagnostic efficiency is improved, but the diagnostic accuracy of the filter fracture detection decreases
Solution Approach 1:
The patent divides the diagnosis processes into separate time slots - the EGR device abnormality diagnosis and the filter fracture diagnosis are executed at different times rather than simultaneously. This segmentation allows each diagnosis to be performed under stable conditions, preventing the EGR valve position changes from interfering with the filter diagnosis accuracy while still maintaining high diagnostic efficiency through systematic scheduling.
2Adaptability or versatility
If the position of the EGR valve is changed during the filter fracture diagnosis, then the EGR device can be diagnosed, but the state of exhaust gas flowing into the filter changes causing diagnostic accuracy to decrease
Solution Approach 1:
The patent performs preliminary determination of diagnosis execution conditions before actually executing the diagnosis processes. It checks whether the current operating conditions are suitable for each type of diagnosis and schedules them appropriately, ensuring that the EGR valve position remains stable during filter fracture diagnosis while still enabling both diagnosis functions to be performed under suitable conditions.
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 ensures high diagnostic accuracy for both the exhaust gas recirculation device and the exhaust gas cleaning filter by avoiding simultaneous execution of diagnosis processes, thereby maintaining the integrity of the filter fracture diagnosis.
Implementation Method 1
an exhaust gas cleaning filter that collects fine particulate matter etc. in exhaust gas
Implementation Method 2
An EGR system recirculates the exhaust gas back to the intake air passage using a differential pressure between the exhaust gas passage and the intake air passage
Implementation Method 3
The EGR valve changes a flow passage area of the exhaust gas recirculated back to the intake air passage through the EGR passage, or so-called EGR gas, as the valve position is changed
Implementation Method 4
a method of diagnosing whether an exhaust gas cleaning filter has a fracture, using measured values of the temperature and the pressure of exhaust gas upstream and downstream of the filter
Data Source
AI summary
Upon a predetermined first diagnosis execution condition being met, an electronic control unit executes a first diagnosis process of diagnosing whether an exhaust gas recirculation device has an abnormality based on an amount of change that a measured value of an intake air pressure undergoes as a result of a change in an EGR valve position. When a predetermined second diagnosis execution condition is met and, moreover, the first diagnosis process is not being executed, the electronic control unit executes a second diagnosis process of diagnosing whether an exhaust gas cleaning filter has a fracture based on measured values of an incoming gas temperature and an outgoing gas temperature.