Fuel Injection Valve Cooling for Exhaust Pipe DPF Regeneration

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Solution Overview

Problem

Existing systems for injecting fuel into an exhaust pipe face issues with fuel content burning and depositing on the spray hole of the fuel injection valve, leading to clogging, especially due to high exhaust gas temperatures.

Innovation Solution

A system where a coolant pipeline is connected to the coolant passage within the exhaust adaptor, the fuel injection valve extends at a predetermined angle from the shaft center of the exhaust pipe, and a cone-shaped concave part is formed to taper from the exhaust path toward the front end of the insertion hole, preventing fuel from adhering to the spray hole and ensuring proper fuel injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fuel is injected directly into the exhaust pipe through a fuel injection valve provided in the exhaust adaptor, then regeneration control efficiency is improved and dilution is prevented, but fuel content burns and deposits on the spray hole causing clogging

Engineering Contradiction:
Improveregeneration control efficiencyVSAvoidspray hole clogging
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A coolant passage is introduced as an intermediary cooling system within the exhaust adaptor. This coolant passage allows coolant to flow through and cool the spray hole area, preventing fuel combustion and deposition without interfering with the fuel injection function. The coolant acts as a mediator between the hot exhaust gas environment and the fuel injection component.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The temperature parameter of the spray hole area is changed by introducing coolant flow. By lowering the local temperature through coolant cooling, the fuel content no longer combusts and deposits on the spray hole, while the overall system maintains high temperature conditions necessary for effective regeneration control.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If post injection is performed to increase exhaust gas temperature for DPF regeneration, then PM burning is achieved, but fuel mixes with engine oil causing dilution and potential engine trouble

Engineering Contradiction:
Improveexhaust gas temperatureVSAvoidengine oil dilution
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The fuel injection function is extracted from the engine combustion system and relocated to the exhaust pipe system. By injecting fuel directly into the exhaust pipe through a dedicated fuel injection valve in the exhaust adaptor, the fuel bypasses the engine oil system entirely, eliminating dilution while still achieving the temperature increase needed for DPF regeneration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The exhaust pipe serves as an intermediary channel that separates the fuel injection process from the engine internal systems. Fuel is injected into the exhaust pipe where it mixes with exhaust gas and burns in a controlled manner to generate heat for DPF regeneration, without contacting engine oil.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2581573B1System for injecting fuel into exhaust pipe
Publication Date: 2017.05.31 ISUZU MOTORS LTD
  • EP2581573B1 patent drawingFigure 1
  • EP2581573B1 patent drawingFigure 2~3(b)
  • EP2581573B1 patent drawingFigure 4

AI summary

Provided is a system for injecting fuel into an exhaust pipe, which is capable of preventing a fuel content of exhaust gas from burning and depositing on a spray hole at a front end of a fuel injection valve. In a system 5 for injecting fuel into an exhaust pipe, an exhaust pipe 11 is connected to an engine 10 via an exhaust adaptor 50 and the fuel is injected directly into the exhaust pipe 11 through a fuel injection valve 52 provided in the exhaust adaptor 50. A front end 52a of the fuel injection valve 52 is provided in an inner wall of an exhaust path 51 located inside the exhaust adaptor 50. The inner wall provided with the front end 52a of the fuel injection valve 52 protrudes from the exhaust path 51 of the exhaust adaptor 50 in a direction in which the diameter of the inner wall expands. A coolant passage 64 for cooling the periphery of the front end 52a of the fuel injection valve 52 is provided within the exhaust adaptor 50.