Internal Combustion Engine Fuel Injection Control for Ignition Stability
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Solution Overview
Problem
In internal combustion engines, the tumble flow is weakened and broken during the compression stroke, leading to reduced combustion stability and unreliable ignition, as the plug discharging channel is not sufficiently extended at ignition timing, affecting the homogeneity of the mixture and ignitability.
Innovation Solution
A control method that imparts fluidity to the vicinity of the ignition plug by performing additional fuel injections after the tumble flow breaks, extending the plug discharging channel and promoting flame core growth, thereby improving combustion stability and ignitability, even under lean-burn or EGR conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If tumble flow is reinforced during compression stroke, then mixture homogeneity is improved, but the tumble flow breaks down before ignition timing and combustion stability deteriorates
Solution Approach 1:
The patent applies preliminary action by performing a first fuel injection during the intake stroke to pre-mix fuel with air and create turbulence before the compression stroke begins. This preliminary turbulence generation ensures that when the tumble flow breaks down later, sufficient mixing has already occurred. The second fuel injection during compression stroke then reinforces the broken turbulence to maintain combustion stability through ignition timing.
Solution Approach 2:
The patent employs periodic action through multi-stage fuel injection: a first injection during the intake stroke, a second injection during the compression stroke, and potentially a third injection near ignition timing. This periodic injection strategy generates turbulence at multiple stages, ensuring continuous mixing and maintaining combustion stability even as the tumble flow evolves and breaks down during compression.
2Reliability
If additional fuel injection is performed after tumble flow breaks, then plug discharging channel is extended and ignitability improves, but injection timing control becomes more complex
Solution Approach 1:
The control device applies preliminary action by determining the tumble flow break timing in advance based on engine operating conditions (load, speed, temperature) and pre-planning the second fuel injection timing. This allows the system to prepare for the tumble flow breakdown and inject fuel at the optimal moment to extend the plug discharging channel, rather than reacting after the breakdown occurs.
Solution Approach 2:
The control device uses feedback by continuously monitoring engine operating parameters (intake air amount, engine speed, temperature) to dynamically adjust the second fuel injection timing. This feedback mechanism allows the system to adapt to changing conditions and maintain optimal ignitability without requiring complex manual tuning or additional sensors.
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 method enhances combustion stability by extending the plug discharging channel, reducing misfires and partial burns, and ensuring stable spark ignition, even in challenging conditions like lean-burn operations or when using EGR, by effectively utilizing turbulence generated by fuel injection patterns.
Implementation Method 1
an angle formed between these fuel sprays is smaller than an angle formed between each of these two fuel sprays and another adjacent fuel spray. The ignition plug is located within a range where turbulence in the air flow is generated.
Data Source
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AI summary
In a control method of an internal combustion engine including a fuel injection valve having a plurality of injection holes and adapted to directly inject a fuel into a cylinder and an ignition plug adapted to generate a plug discharging channel, after fuel injection is performed, spark ignition is performed while turbulence in an air flow is generated by the fuel injection by an ignition plug disposed so that a discharging region is sandwiched by fuel sprays injected from the two adjacent injection holes and located within a range where the turbulence in the air flow is generated.