Exhaust Gas Purification Device Injection Path Scavenging
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Solution Overview
Problem
In exhaust gas purification devices for diesel engines, the fuel injection path often experiences stagnation and deposit formation due to evaporation of fuel, leading to potential clogging and reduced functionality of the fuel addition valve.
Innovation Solution
Incorporating an inflow portion in the exhaust passage that allows a portion of the exhaust gas to flow into the fuel injection path, combined with a scavenging flow mechanism, such as a collision or swirl flow, to reduce stagnation and deposit generation within the path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the fuel injection path is retreated from the exhaust passage to avoid high-temperature exposure, then the fuel addition valve is protected from heat damage, but stagnation and deposit formation occur in the injection path
Solution Approach 1:
The patent introduces exhaust gas as an intermediary substance that flows through the fuel injection path to prevent stagnation. The exhaust gas acts as a carrier that continuously moves through the injection path, preventing fuel evaporation residues from accumulating and forming deposits, thus maintaining injection path functionality while allowing the valve to be positioned away from direct high-temperature exposure.
Solution Approach 2:
The system uses the exhaust gas flow that already exists in the exhaust passage to serve the dual purpose of exhaust removal and injection path scavenging. The exhaust gas naturally flowing through the system is utilized to clean the injection path, eliminating the need for additional active scavenging mechanisms while maintaining reliable injection path operation.
2Object-affected harmful factors
If the fuel injection path is extended away from the exhaust gas flow, then heat-resistant temperature protection is achieved, but deposit accumulation blocks the injection path
Solution Approach 1:
Exhaust gas is introduced as an intermediary flow that continuously passes through the extended fuel injection path. This exhaust gas flow prevents fuel evaporation residues from accumulating by maintaining continuous motion and providing a carrier gas that sweeps through the injection path, thereby preventing deposit formation even though the path is extended away from direct heat sources.
Solution Approach 2:
The patent employs pneumatic principles by utilizing the exhaust gas flow dynamics to scavenge the injection path. The pressure and velocity of the exhaust gas create a flowing environment that prevents stagnant zones where deposits would form, using gas flow mechanics to maintain a clean injection path over extended distances from the heat source.
3Temperature
If the fuel addition valve is positioned far from the exhaust gas, then heat-resistant protection is provided, but exhaust gas flow cannot reach the injection path interior
Solution Approach 1:
The patent uses exhaust gas as an intermediary that is actively channeled into the extended injection path through dedicated flow paths. This ensures that even though the valve is positioned far from the direct exhaust gas flow, the exhaust gas still reaches and flows through the injection path interior at sufficient velocities to prevent stagnation and maintain cleaning action.
Solution Approach 2:
The exhaust gas flow system is segmented into different flow paths: one for the main exhaust passage and another dedicated path that channels exhaust gas into the fuel injection path. This segmentation allows the injection path to be positioned away from the main heat source while still receiving sufficient exhaust gas flow through its own dedicated channel, maintaining both thermal protection and adequate flow velocity.
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 configuration effectively prevents the accumulation of fuel and soot in the injection path, ensuring continuous and efficient operation of the fuel addition valve and maintaining exhaust gas purification performance.
Implementation Method 1
a flow of the exhaust gas flowing through the exhaust passage is hard to reach the inside of the fuel injection path
Implementation Method 2
the fuel evaporated in the fuel injection path can easily collect in the fuel injection path
Implementation Method 3
The evaporated fuel accumulated in the fuel injection path becomes a binder to have soot contained in the exhaust gas adhere to a wall surface of the fuel injection path and generate a deposit
Data Source
AI summary
The exhaust gas purification device of an internal combustion engine of the present invention comprises an exhaust passage for guiding an exhaust gas exhausted from an engine to outside, a catalyst provided in the exhaust passage, an injection path connected on an upstream side of the catalyst in the exhaust passage, an additive injection valve installed in the injection path for supplying an additive to the catalyst through the injection path, and an inflow portion provided in a merging portion where the exhaust passage and the injection path merge for having a part of the exhaust gas flowing in the exhaust passage flow into the injection path.