Fuel Injector Cooling Feature Using Leakage Path

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Fuel injectors in diesel engines experience heat generation due to pressure differentials leading to fuel leakage, which can degrade components like solenoids, especially under high-pressure conditions exceeding 170 MPa, and existing cooling methods are insufficient to manage this heat effectively.

Innovation Solution

A fuel injector design incorporating a cooling feature with a leakage path fluidly connecting the common rail inlet port to a fuel drain port, and a cooling path connecting a cooling inlet port to the fuel drain port, allowing for the movement of cooling fuel and leakage fuel to combine and exit through the fuel drain port, effectively dissipating heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fuel is moved through the injector during multiple injection events, then fuel injection performance is improved, but heat is generated due to pressure differentials and fuel leakage

Engineering Contradiction:

Improveinjection events per combustion phaseVSAvoidinjector component temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent converts the harmful effect of fuel leakage (which generates heat) into a beneficial cooling mechanism. The leakage path is designed to allow fuel to flow from the high-pressure common rail inlet port through the actuator to the fuel drain port, using the pressure differential to drive cooling fuel flow that absorbs heat from the actuator and surrounding components, thereby converting the harmful heat-generating leakage into a useful cooling function.

Inventive Principle:

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

Solution Approach 2:

The fuel serving multiple functions: it acts as both the injection medium for combustion and as a cooling fluid for the actuator. The same fuel that leaks through the system (which would normally be considered waste or harmful) is utilized as a cooling agent, allowing the system to perform both injection and cooling functions using the same fluid resource.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If electrical energy is increased to achieve multiple injections, then injection control capability is improved, but heat generation in the actuator increases

Engineering Contradiction:

Improvemultiple injection capabilityVSAvoidactuator temperature

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The patent converts the harmful heat generated by electrical actuation into a beneficial effect by using the surrounding fuel (which absorbs this heat) as a cooling medium. The fuel in contact with the actuator absorbs the heat generated during multiple energization events, and this heated fuel is then discharged through the drain port, effectively removing heat from the actuator while enabling versatile multiple injection control.

Inventive Principle:

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

3Stress or pressure

If high pressure is maintained in the common rail inlet port, then fuel injection performance is improved, but fuel leakage and heat generation increase

Engineering Contradiction:

Improvecommon rail pressureVSAvoidinjector temperature

Core Design Contradiction:

Stress or pressureVSTemperature

Solution Approach 1:

The patent uses hydraulic principles by utilizing the pressure differential between the high-pressure common rail inlet port and the low-pressure fuel drain port to drive the flow of cooling fuel through the actuator. This hydraulic flow mechanism naturally removes heat from the high-pressure region without requiring additional mechanical cooling components, effectively managing thermal loads while maintaining high injection pressure.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 cooling feature effectively manages heat dissipation by combining leakage and cooling fuel, reducing the temperature of injector components and preventing degradation, even at high-pressure conditions, thereby enhancing the performance and reliability of fuel injectors.

Implementation Method 1

Any leakage of fuel that occurs at these higher fuel pressures tends to generate heat in the vicinity of the leakage path and the heat is transferred to the injector components

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The '059 patent teaches the use of an external cooling liquid to cool the piezoelectric actuator by allowing the liquid to flow around the actuator

Methodology Applied

Scientific EffectConvection cooling: Convection

Implementation Method 3

The pressure differential between the various parts of the fuel injectors can create potential leakage paths

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS7849836B2Cooling feature for fuel injector and fuel system using same

Publication Date: 2010.12.14 CATERPILLAR INC

AI summary

A thermal load control assembly for a fuel injector includes a rail inlet port, a cooling inlet port and a fuel drain port. A leakage path channels leaked fuel originating from the rail inlet port to the fuel drain port. A cooling path channels fuel originating from the cooling inlet port to the fuel drain port. A fuel system using a thermal load control assembly includes a single fuel tank that supplies fuel to the rail inlet port and the cooling inlet port of a plurality of fuel injectors and collect fuel from the fuel drain port of the plurality of fuel injectors.