Engine Intake Bypass Valve Control for NOx Adsorption
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Solution Overview
Problem
When exhaust gas is recirculated to the upstream side of the bypass passage in an internal combustion engine, the NOx in the exhaust gas is adsorbed at the evaporated fuel adsorption device, leading to a decrease in its fuel adsorption ability.
Innovation Solution
A control system is implemented with a bypass passage that bypasses the throttle valve through the evaporated fuel adsorption device, where exhaust gas is recirculated through an exhaust gas recirculation passage with an exhaust control valve and an intake control valve. The intake control valve is fully closed or reduced in opening degree when the exhaust control valve's opening degree exceeds a set point, preventing excessive NOx adsorption and maintaining the fuel adsorption ability of the evaporated fuel adsorption device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas is recirculated to the upstream side of the bypass passage, then exhaust gas recirculation is achieved for NOx reduction, but the evaporated fuel adsorption device loses its adsorption ability due to NOx adsorption
Solution Approach 1:
The bypass passage is designed to be dynamically controllable through the intake control valve, allowing the system to switch between different operational states. When exhaust gas recirculation is active, the valve closes the bypass passage to prevent NOx from reaching the adsorption device, while maintaining the ability to open the passage when recirculation is inactive for fuel discharge purposes
Solution Approach 2:
The intake control valve acts as an intermediary element that mediates between the exhaust gas recirculation system and the evaporated fuel adsorption system. By controlling the valve opening, the system selectively allows or blocks the flow of exhaust gas through the bypass passage, thereby protecting the adsorption device from NOx while enabling fuel discharge when needed
2Productivity
If the bypass passage is used for fuel discharge, then evaporated fuel can be discharged to the downstream side of the throttle valve, but exhaust gas may pass through and adsorb at the evaporated fuel adsorption device
Solution Approach 1:
The system dynamically controls the bypass passage availability based on operational conditions. The intake control valve opens the bypass passage to enable fuel discharge to the downstream side of the throttle valve when exhaust gas recirculation is not active, while closing the passage when recirculation is active to prevent NOx contamination of the adsorption device
Solution Approach 2:
The control system uses feedback from the exhaust gas recirculation operation state to control the intake control valve. When the exhaust gas recirculation valve is open, the system detects this state and responds by closing the bypass passage, thereby preventing the harmful effect of NOx adsorption while maintaining fuel discharge capability when recirculation is inactive
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 control system effectively suppresses the adsorption of NOx at the evaporated fuel adsorption device, preventing a drop in its fuel adsorption ability and ensuring efficient fuel discharge to the engine intake system, thereby maintaining the device's performance.
Implementation Method 1
an evaporated fuel adsorption device which adsorbs evaporated fuel in a fuel tank is provided
Implementation Method 2
exhaust gas is made to recirculate through an exhaust gas recirculation passage which is connected to an upstream side from an inlet of the bypass passage
Data Source
AI summary
The control device of an internal combustion engine of the present invention is a control device of an internal combustion engine in which a bypass channel (25) for bypassing a throttle valve (6) of an engine intake system (5) via an evaporated fuel adsorption device is provided as a fuel emission path to an evaporated fuel adsorption device (22) for adsorbing evaporated fuel in a fuel tank (19), and exhaust gas recirculation is implemented for recirculating exhaust gas via an exhaust gas recirculation passage (17) connected upstream of the entrance of the bypass channel of the engine intake system. An exhaust control valve (18) is disposed in the exhaust gas recirculation passage, intake control valves (27, 28) are disposed in the bypass channel, and when the opening degree of the exhaust control valve is greater than a set opening degree, either the intake control valve is fully closed or the opening degree of the intake control valve is reduced in comparison with times when the opening degree of the exhaust control valve is equal to or less than the set opening degree.