EGR Valve Cycling to Clear Obstructions Before Engine Restart
Solution Overview
Problem
Existing EGR valves in internal combustion engines can become obstructed by foreign matter during idle stops or engine stalls, preventing complete closure and causing difficulties in restarting the engine due to EGR gas entering the combustion chamber.
Innovation Solution
An EGR valve control apparatus that includes a detector to identify foreign matter obstruction and a controller to perform controlled opening and closing operations to remove the obstruction, ensuring the valve can close fully and maintain engine restartability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the EGR valve is left closed during idle stop or engine stall, then the valve structure is simple and energy consumption is low, but foreign matter accumulates and causes obstruction preventing complete closure
Solution Approach 1:
The controller performs preliminary opening and closing operations of the EGR valve before engine restart to prevent foreign matter accumulation and ensure complete closure. This preliminary action removes potential obstructions before they cause reliability issues during actual engine operation.
Solution Approach 2:
The EGR valve performs periodic opening and closing operations during idle stop or engine stall conditions. This periodic action prevents foreign matter accumulation by repeatedly opening and closing the valve, ensuring it can complete full closure when needed without requiring continuous operation.
2Reliability
If the EGR valve performs opening and closing operations to remove foreign matter, then the valve reliability is improved, but power consumption increases and driver discomfort may occur
Solution Approach 1:
The opening and closing operations are performed preliminarily during idle stop or stall before engine restart is attempted. This timing ensures the valve is clear of foreign matter before restart, improving reliability without causing discomfort during active driving.
Solution Approach 2:
The valve performs periodic opening and closing operations only during specific idle conditions rather than continuously. This selective periodic action removes foreign matter when needed while minimizing power consumption and avoiding driver discomfort during normal operation.
3Reliability
If the EGR valve is fully opened to remove foreign matter, then the obstruction is cleared, but EGR gas may flow into the combustion chamber causing restart difficulty
Solution Approach 1:
The full opening operation is performed preliminarily during idle stop or stall when the engine is not running. This timing ensures foreign matter is removed before restart while the combustion chamber is not actively drawing in gases, preventing harmful EGR gas flow during the opening operation.
Solution Approach 2:
The valve performs periodic full opening operations during idle conditions to clear foreign matter. These operations occur when the engine is stationary and not drawing intake air, eliminating the risk of EGR gas entering the combustion chamber while maintaining valve reliability.
Data Source
AI summary
An EGR valve control apparatus includes: an EGR valve configured to adjust an exhaust gas recirculation amount of an internal combustion engine mounted on a vehicle, a detector configured to detect a caught state in which foreign matter is caught in the EGR valve, and a controller configured to control the EGR valve. The controller controls the EGR valve to perform an opening and closing operation, in which the EGR valve opens and closes a predetermined number of times, on condition that the caught state is detected by the detector when rotation of the internal combustion engine is stopped in a state where an ignition switch of the vehicle is on.