Precombustion Chamber Fuel Control for Engine Misfiring

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Solution Overview

Problem

Conventional engine control methods for precombustion chambers fail to prevent misfiring due to transient fuel-rich conditions, leading to decreased engine speed and ignition difficulties, especially when engine load or speed changes abruptly.

Innovation Solution

A control method that adjusts the fuel supply to the precombustion chamber based on the air excess ratio of the air-fuel mixture in the main combustion chamber, ensuring an appropriate air-fuel ratio by continuously measuring charging air pressure, temperature, and engine speed, and calculating the necessary fuel amount and valve opening duration for the precombustion chamber fuel supply valve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fuel supply to the precombustion chamber is increased to prevent misfiring, then reliability of ignition is improved, but fuel efficiency deteriorates due to excessive fuel consumption

Engineering Contradiction:
Improveignition reliabilityVSAvoidfuel consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The control method performs preliminary detection of engine speed and load conditions, and preemptively adjusts the fuel supply amount to the precombustion chamber before misfiring occurs. By detecting transient fuel-rich conditions in advance and pre-adjusting the air-fuel ratio, the system prevents misfiring without requiring excessive fuel supply, thus resolving the contradiction between ignition reliability and fuel efficiency.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If conventional control methods are used to maintain air-fuel ratio, then steady-state operation is stable, but transient response deteriorates during abrupt engine load or speed changes

Engineering Contradiction:
Improveair-fuel ratio stabilityVSAvoidtransient response speed
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The control method dynamically adjusts the fuel supply amount to the precombustion chamber based on real-time detection of engine speed and load conditions. Unlike conventional fixed control methods, this dynamic adjustment allows the system to rapidly respond to transient changes in engine operation, maintaining stable air-fuel ratio during both steady-state and transient conditions, thereby resolving the contradiction between stability and transient response speed.

Inventive Principle:
Principle #15Dynamics

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 effectively prevents misfiring in the precombustion chamber by maintaining an optimal air-fuel ratio, even during abrupt changes in engine speed or load, thereby stabilizing engine performance and preventing stalling.

Implementation Method 1

a spark (ignition) plug 4 is provided for igniting the air fuel-gas mixture in the precombustion chamber S2

Methodology Applied
Scientific EffectSpark ignition: Electric Spark

Implementation Method 2

a precombustion chamber fuel supply valve 6 for regulating the flow amount of the fuel is provided

Methodology Applied
Scientific EffectValve flow control: Valve

Data Source

PatentEP2402582B1Method of controlling auxiliary chamber type engine
Publication Date: 2020.10.28 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD
  • EP2402582B1 patent drawingFigure 1
  • EP2402582B1 patent drawingFigure 2
  • EP2402582B1 patent drawingFigure 3(a)~3(e)

AI summary

Providing a control method for controlling an engine of a precombustion chamber type, whereby the misfiring in the precombustion chamber is surely prevented. In the control method for controlling an engine of a premix combustion type, the method including, but not limited to the processes of: a first step where the charging air pressure, the charging air temperature and the engine speed are detected; a second step where the air excess ratio of the air fuel mixture supplied to the main combustion chamber is computed as per predetermined relational expressions; a third step where the amount of the fuel to be supplied to the precombustion chamber is duly computed as per the relational expression between the air excess ratio of the air fuel mixture in the main combustion chamber and the fuel amount of the air fuel mixture in the precombustion chamber; a fourth step where the valve opening duration regarding a precombustion chamber fuel supply valve for controlling the amount of the fuel to be supplied to the precombustion chamber is computed as per a relational expression between the valve opening duration and the computed fuel amount of the air fuel mixture in the precombustion chamber.