EGR Valve Control During DPF Regeneration
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Solution Overview
Problem
Conventional methods suspend EGR control during DPF regeneration, leading to increased NOx levels in exhaust gas and potential damage to EGR cooler and piston ring due to oil dilution and unburnt fuel contamination.
Innovation Solution
An exhaust pipe injection control device that injects fuel downstream of the EGR piping connecting portion in the exhaust pipe, allowing for optimal control of EGR opening during DPF regeneration using a regeneration-time opening map to adjust the EGR valve opening based on engine rotation speed and fuel injection amount, ensuring the EGR is fully closed when the fuel injection amount is below a predetermined value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If EGR control is suspended during DPF regeneration, then post-injection can be performed to raise exhaust gas temperature, but NOx levels in exhaust gas increase
Solution Approach 1:
The patent changes the control parameter of EGR valve opening during DPF regeneration by introducing a regeneration-time opening map that dynamically adjusts the EGR opening degree based on engine rotation speed and fuel injection amount. This allows EGR control to be maintained during regeneration rather than suspended, thereby reducing NOx emissions while still enabling temperature rise through controlled post-injection.
2Temperature
If post-injection is performed to raise exhaust gas temperature for DPF regeneration, then PM can be incinerated, but oil dilution occurs causing EGR cooler failure or piston ring damage
Solution Approach 1:
The patent uses the EGR valve as an intermediary control mechanism to regulate the amount of exhaust gas recirculated during post-injection. By controlling the EGR opening degree based on fuel injection amount and engine rotation speed, the system prevents excessive fuel from entering the EGR cooler and piston ring, thereby avoiding oil dilution and related damage while still enabling effective DPF regeneration.
3Productivity
If EGR control is suspended during DPF regeneration, then fuel injection for regeneration can proceed, but engine performance declines due to unburnt fuel mixing in EGR device
Solution Approach 1:
The patent implements a feedback control system that continuously monitors engine rotation speed and fuel injection amount during DPF regeneration, then adjusts the EGR valve opening degree accordingly through the regeneration-time opening map. This feedback mechanism ensures that EGR control is dynamically optimized to prevent unburnt fuel from damaging the EGR device while maintaining effective regeneration productivity.
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 optimally controls EGR opening during DPF regeneration, reducing NOx emissions and preventing oil dilution and EGR cooler contamination, thereby protecting the EGR system and maintaining engine performance.
Implementation Method 1
supplying hydrocarbon (hereinafter referred to as HC) to the DOC by the post-injection, and raising the exhaust gas temperature to PM incineration temperature using heat produced by oxidation of the HC
Implementation Method 2
an exhaust pipe is provided with a diesel particulate filter (hereinafter referred to as a DPF) in order to remove particulate matter (hereinafter referred to as PM) from exhaust gas from the diesel engine to purify the exhaust gas. A DPF is designed to collect PM in a honeycomb structure constituted by a porous ceramic
Implementation Method 3
an exhaust gas recirculation device which circulates exhaust gas from an exhaust manifold to an intake manifold of the engine according to a degree of opening
Data Source
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AI summary
Provided is an exhaust pipe injection control device capable of optimally controlling an degree of EGR opening during DPF regeneration. The device comprises a regeneration-time opening control unit (173) which controls a degree of EGR opening of an EGR device (123) during DPF regeneration. The device further comprises a regeneration-time opening map (172) in which an optimal degree of EGR opening of the EGR device (123) during DPF regeneration is set in advance according to an engine rotation speed and a fuel injection amount of an engine (101). The regeneration-time opening control unit (173) performs exhaust gas recirculation by referring to the regeneration-time opening map (172) based on the engine rotation speed and the fuel injection amount of the engine (101) and controlling the degree of EGR opening of the EGR device (123).