Common-Rail Injector Backflow Actuation for Engine Starting

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Solution Overview

Problem

Common-rail fuel injectors in combustion engines generate a backflow of fuel that is often returned to the tank, resulting in energy loss and inefficient fuel management, particularly during engine starting when the fuel pump cannot provide sufficient pressure to operate actuators efficiently.

Innovation Solution

A method and system where the backflow of fuel from the common-rail injector is utilized to power an actuator by opening a valve, allowing the backflow to flow to the actuator, thereby reducing energy loss and ensuring efficient fuel usage during engine starting and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If backflow fuel is returned directly to the fuel tank, then the fuel system is simple to operate, but energy is lost and fuel management becomes inefficient

Engineering Contradiction:

Improveenergy loss from backflowVSAvoidfuel system complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent converts the harmful waste energy in the backflow fuel into a beneficial resource by using it to power actuators. The backflow fuel, which was previously discarded to the tank, is now routed through actuators to provide hydraulic power during engine starting and operation, transforming an energy loss into a useful function.

Inventive Principle:

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

Solution Approach 2:

The backflow fuel serves multiple functions: it maintains pressure in the fuel system, powers actuators for starting valve operation, and returns to the tank when not needed. This multi-functional use of the same fuel stream eliminates energy waste while avoiding the need for separate hydraulic systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Power

If fuel pump provides high pressure to operate actuators during engine starting, then actuators operate efficiently, but the fuel pump cannot provide sufficient pressure during cranking

Engineering Contradiction:

Improveactuator operating pressureVSAvoidactuator operation reliability during starting

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The system stores energy in the pressurized fuel rail before engine starting is needed. During normal operation, the fuel pump maintains high pressure in the rail, preparing the system in advance. When starting is required, this pre-stored pressure immediately powers the actuators without requiring the fuel pump to suddenly provide high pressure during cranking.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fuel rail acts as an intermediary energy storage device between the fuel pump and the actuators. It decouples the pump's continuous operation from the actuators' intermittent high-power needs, allowing the actuators to receive high pressure even when the pump cannot provide it during engine cranking.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If backflow pressure is maintained within certain limits, then injection behavior variability is maintained within a small range, but fuel management efficiency decreases

Engineering Contradiction:

Improveinjection behavior stabilityVSAvoidfuel management efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The backflow fuel self-regulates its own pressure by passing through the actuators, which are designed to operate within specific pressure ranges. The actuator circuits naturally limit the pressure while utilizing the backflow energy, eliminating the need for external pressure regulation mechanisms that would reduce efficiency.

Inventive Principle:

Principle #25Self-service

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 enhances fuel management by utilizing the energy from the backflow to power actuators, maintaining efficient operation and reducing leakage, especially during engine cranking when traditional fuel pressures are insufficient.

Implementation Method 1

The fuel has to be highly pressurized first before being expanded, and heat may be generated as a result of the pressure change and/or the expansion of the backflow

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

heat may be generated as a result of the pressure change and/or the expansion of the backflow

Methodology Applied

Scientific EffectHeat generation from pressure change: Joule Heating

Implementation Method 3

powering an actuator by opening a valve, allowing the backflow to flow to the actuator

Methodology Applied

Scientific EffectFluid pressure actuation: Hydraulic Press

Data Source

PatentUS10865728B2Method of using backflow from common-rail fuel injector

Publication Date: 2020.12.15 PRATT & WHITNEY CANADA CORP

AI summary

There is disclosed a method of operating an engine assembly including a combustion engine and a common-rail injector. The method includes: injecting fuel into a combustion chamber of the combustion engine via the common-rail injector thereby generating a backflow of fuel; and powering an actuator using at least a portion of the backflow of fuel. An engine assembly including the combustion engine is disclosed; the engine assembly having a fuel circuit fluidly connecting a fuel source, the common-rail injector, and the second injector outlet together. The fuel circuit has an actuator sub-circuit operatively connected to an outlet of the common-rail injector and an actuator fluidly connected to the actuator sub-circuit.