Fuel Injection Valve Leak Return Layout for Cylinder Detection

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Solution Overview

Problem

Conventional fuel systems face challenges in preventing fuel leaks from the connection parts between fuel injection valves and fuel supply pipes, making it difficult to identify the specific valve causing the leak and resulting in unintended discharge of leaked fuel outside.

Innovation Solution

A fuel system with a fuel leak detection device comprising a leaked fuel return passage, an inspection hole, a plug member, and a check valve to prevent external leakage and facilitate detection of the leaking cylinder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If a detection hole is provided on the leaked fuel return pipe to identify the leaking fuel injection valve, then the leaking cylinder can be detected, but fuel is discharged to the outside through the detection hole

Engineering Contradiction:
Improvefuel leak detection capabilityVSAvoidfuel discharge to outside
Core Design Contradiction:
Difficulty of detecting and measuringVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a container as an intermediary component between the leaked fuel return passage and the external environment. The container receives leaked fuel and allows for controlled inspection through an opening, preventing direct discharge to the outside while enabling detection of the leaking cylinder by examining accumulated fuel in the container.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If multiple fuel injection valves are installed in the diesel engine, then the engine can operate with multiple cylinders, but it becomes difficult to identify the specific valve from which fuel is leaking

Engineering Contradiction:
Improveengine multi-cylinder operationVSAvoidfuel leak source identification
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies segmentation by providing separate leaked fuel return passages for different fuel injection valves (e.g., first leaked fuel return passage for first valve, second leaked fuel return passage for second valve). Each passage leads to a container, allowing the operator to identify which specific valve is leaking by determining which container contains leaked fuel, thus maintaining multi-cylinder operation while enabling precise leak source identification.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the end of the fuel supply pipe is pressed against the fuel supply port of the fuel injection valve (metal touch connection), then the connection is secure, but fuel leak may occur at the connection part

Engineering Contradiction:
Improveconnection securityVSAvoidfuel leakage at connection
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of fuel leakage at the metal touch connection into a beneficial detection opportunity. By providing a leaked fuel return passage that collects leaked fuel from the connection part and directs it to a container, the system transforms the leak from a purely harmful event into a detectable condition that can be easily identified by checking the container for accumulated fuel.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The system effectively prevents fuel leaks and allows accurate identification of the leaking cylinder, ensuring fuel is contained within the system and detected efficiently.

Implementation Method 1

a check valve that is provided on the leaked fuel return passage to prevent fuel from flowing to the connection part side

Methodology Applied
Scientific EffectCheck valve one-way flow control: Valve

Data Source

PatentEP4446577B1Fuel system
Publication Date: 2026.04.01 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD
  • EP4446577B1 patent drawingFigure 1
  • EP4446577B1 patent drawingFigure 2
  • EP4446577B1 patent drawingFigure 3

AI summary

Provided are a fuel injection valve; a fuel supply passage that supplies fuel to the fuel injection valve; a fuel return passage that returns excess fuel of the fuel injection valve; a leaked fuel return passage one end of which is coupled to a connection part between the fuel injection valve and the fuel supply passage, and the other end of which is coupled to the fuel return passage; an inspection hole provided on the leaked fuel return passage, and that is openable and closable by a plug member; and a check valve provided on the leaked fuel return passage, and that prevents fuel from flowing to the connection part side.