Engine Controller Fuel Injection Strategy for Stuck EGR Valve
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Solution Overview
Problem
During idle operation of an internal combustion engine with an EGR device, if the EGR valve is not fully closed due to sticking or foreign matter, it leads to deterioration of the combustion state and potential drop in engine rotation speed, as EGR gas flows through and negatively affects air-fuel mixing.
Innovation Solution
A control system that adjusts fuel injection between the in-passage and in-cylinder fuel injection valves, reducing fuel injection from the in-passage valve and increasing it from the in-cylinder valve, and potentially increasing the injection pressure of the in-cylinder valve when the EGR valve is not fully closed, to promote air-fuel mixing and maintain combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the EGR valve is opened during idle operation to reduce EGR gas temperature, then the temperature of EGR gas is reduced, but the combustion state deteriorates and engine rotation speed drops
Solution Approach 1:
The control system changes the operating parameters by switching from EGR valve control to direct fuel injection control. When the engine is in idle operation or low-load state, the controller increases the amount of fuel injection from the in-cylinder fuel injection valve, thereby changing the combustion parameters to compensate for the lack of EGR valve opening capability, maintaining combustion stability without relying on EGR temperature reduction
2Reliability
If fuel injection amount is increased to compensate for EGR valve abnormality, then combustion state deterioration is suppressed, but noise from in-cylinder fuel injection valve increases
Solution Approach 1:
The system segments the fuel injection function into two parts: in-passage fuel injection valve and in-cylinder fuel injection valve. When EGR valve abnormality is detected during idle operation, the controller increases fuel injection from the in-cylinder valve while simultaneously reducing or stopping injection from the in-passage valve, thereby concentrating the injection function in one component and managing the noise trade-off
3Object-generated harmful factors
If in-passage fuel injection is used during idle operation to reduce noise, then operation sound is reduced, but combustion efficiency decreases when EGR valve is not fully closed
Solution Approach 1:
The control system dynamically switches between different fuel injection strategies based on engine operating conditions and EGR valve status. During idle operation with normal EGR valve, the system uses in-passage injection for low noise. When EGR valve abnormality is detected, the system dynamically transitions to in-cylinder injection with increased fuel amount, adapting the injection strategy to maintain combustion reliability while managing noise
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 effectively suppresses combustion state deterioration and reduces noise by optimizing fuel injection patterns and pressures, ensuring stable engine operation even when the EGR valve is not fully closed.
Implementation Method 1
fuel of high pressure is injected from the in-cylinder fuel injection valve
Implementation Method 2
an in-cylinder fuel injection valve configured to inject fuel into a cylinder of the internal combustion engine
Implementation Method 3
an in-passage fuel injection valve configured to inject fuel into an intake passage of the internal combustion engine
Implementation Method 4
an EGR valve for opening and closing the EGR passage
Implementation Method 5
EGR gas will flow through the EGR valve
Implementation Method 6
mixing of air and fuel does not proceed effectively
Data Source
AI summary
There is provided a controller configured to carry out at least one of first control and second control, in cases where the internal combustion engine is in a predetermined operating state in which the EGR valve is caused to be fully closed, the first control being that an amount of fuel to be injected into an intake passage is made smaller, and an amount of fuel to be injected into a cylinder is made larger, in the presence of the abnormality of the EGR valve being not fully closed than in the absence of the abnormality, and the second control being that a pressure of fuel to be injected into the cylinder is made higher in the presence of the abnormality of the EGR valve being not fully closed than in the absence of the abnormality.