Gaseous Fuel Injection Control for Engine State Adaptation

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Solution Overview

Problem

Gaseous-fuelled internal combustion engines require sophisticated electronic control to manage ignition and injection timing due to differences from conventional diesel engines, necessitating a more advanced fuel injection control method that adapts to various engine states and operating conditions to maintain performance and reduce emissions.

Innovation Solution

A fuel injection control method that receives input data on engine speed and operating conditions, using look-up tables to adjust gaseous fuel rail pressure, injection timing, and pilot fuel parameters based on predefined engine states such as normal operation, particulate filter regeneration, and altitude, ensuring optimal combustion and emission control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If gaseous fuel is substituted for diesel fuel, then emissions are reduced, but ignition reliability deteriorates

Engineering Contradiction:
ImproveemissionsVSAvoidignition reliability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent introduces an intermediary substance (pilot fuel or glow plug) to facilitate the ignition of gaseous fuel. The pilot fuel, typically a small amount of diesel or another combustible liquid, is injected first to create a flame that then ignites the main gaseous fuel charge. Alternatively, a glow plug provides a hot surface to initiate combustion. This intermediary mechanism resolves the contradiction by enabling reliable ignition of gaseous fuel without requiring higher compression ratios, thus maintaining emissions benefits while achieving ignition reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If conventional diesel engine compression ratio is used, then engine simplicity is maintained, but gaseous fuel ignition fails

Engineering Contradiction:
Improveengine simplicityVSAvoidignition reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs an intermediary ignition aid (pilot fuel injection system or glow plug) that allows the engine to maintain its original compression ratio and basic structure. This approach preserves engine simplicity while solving the ignition problem of gaseous fuel, avoiding the need to redesign the engine with higher compression ratios or completely new ignition systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the ignition approach parameter from relying solely on compression heat to using an external ignition source (pilot fuel or glow plug). This parameter change allows the engine to continue operating with conventional compression ratios while reliably igniting gaseous fuel, thus maintaining structural simplicity while achieving reliable combustion.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If sophisticated electronic control is implemented, then fuel injection precision is improved, but system complexity increases

Engineering Contradiction:
Improvefuel injection precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback control mechanisms where sensors monitor engine parameters (such as crankshaft position, fuel pressure, temperature, and emission levels) and the electronic control unit continuously adjusts injection timing, duration, and pilot fuel ratios accordingly. This feedback system achieves precise fuel injection control adapted to varying operating conditions while managing system complexity through integrated electronic management that coordinates multiple subsystems efficiently.

Inventive Principle:
Principle #23Feedback

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 method enables efficient and adaptive fuel injection strategies, matching the power and efficiency of conventional diesel engines while reducing emissions and improving responsiveness to different operating conditions.

Implementation Method 1

gaseous fuels can be injected into an engine's combustion chamber at lower pressure because no extra energy is required for fuel atomization

Methodology Applied
Scientific EffectGas injection:

Implementation Method 2

the heat produced by the mechanical compression of the fuel and air mixture auto-ignites the liquid diesel fuel charge at or near the end of the piston's compression stroke

Methodology Applied
Scientific EffectAuto-ignition:

Implementation Method 3

the heat produced by the mechanical compression of the fuel and air mixture auto-ignites the liquid diesel fuel charge

Methodology Applied
Scientific EffectCompression heating: Adiabatic Heating

Implementation Method 4

an ignition assisting device, such as a hot surface provided by a glow plug

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2283221B1Fuel injection control method for a direct injection gaseous-fuelled internal combustion engine
Publication Date: 2019.10.09 WESTPORT FUEL SYST CANADA INC
  • EP2283221B1 patent drawingFigure 1
  • EP2283221B1 patent drawingFigure 2
  • EP2283221B1 patent drawingFigure 3

AI summary

The method comprises receiving from the vehicle controller, values associated with the engine speed and of another parameter indicative of the engine operating conditions, such as the total fuelling amount, and controlling the fuel injection parameters according to the engine state, which, for example, can include a normal operation mode, a filter regeneration mode, an engine protection mode, high or low transient load modes, and operating at different altitudes, through algorithms implemented in an electronic controller.