Adjustable Fuel Spray Angle for Pre-Ignition Mitigation
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Solution Overview
Problem
Engines with high compression ratios or boosted for increased output are prone to low-speed pre-ignition, leading to high in-cylinder pressures and combustion knock, which existing mitigation strategies, such as early fuel injection, can exacerbate due to fuel impingement on cylinder walls, causing wall wetting and abnormal combustion.
Innovation Solution
An engine control system adjusts the spray angle and pattern of fuel injection based on pre-ignition likelihood, using split injections and timing adjustments to reduce cylinder wall impingement and improve air-fuel mixing, thereby mitigating pre-ignition and enhancing engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If early fuel injection timing is used to achieve cylinder charge cooling and reduce pre-ignition, then pre-ignition mitigation is improved, but fuel impingement on cylinder walls increases causing wall wetting and abnormal combustion
Solution Approach 1:
The patent applies dynamics by making the spray angle adjustable rather than fixed. The fuel injector's spray angle is dynamically modified based on engine operating conditions and detected pre-ignition events. When pre-ignition is detected, the spray angle is reduced to prevent fuel from impinging on cylinder walls, while maintaining early injection timing for charge cooling. This dynamic adjustment resolves the contradiction between achieving charge cooling and preventing wall wetting.
Solution Approach 2:
The patent changes the spray angle parameter of the fuel injection system to resolve the technical contradiction. By modifying the spray angle parameter in response to detected pre-ignition events, the system optimizes fuel distribution - using narrower angles to prevent wall impingement while maintaining the early injection timing needed for charge cooling effects.
2Object-generated harmful factors
If spray angle is reduced to prevent fuel impingement on cylinder walls, then wall wetting is reduced, but air-fuel mixing may be compromised
Solution Approach 1:
The system dynamically adjusts spray angle based on real-time engine conditions and pre-ignition detection. During normal operation, a wider spray angle promotes good air-fuel mixing. When pre-ignition is detected, the spray angle is temporarily narrowed to prevent wall impingement. The system maintains mixing quality by coordinating spray angle changes with injection timing and duration adjustments, ensuring adequate fuel atomization and distribution even with narrower angles.
Solution Approach 2:
The system performs preliminary detection of pre-ignition conditions and adjusts spray angle in advance to prevent harmful wall wetting. By monitoring engine parameters and detecting pre-ignition trends before they fully develop, the system can proactively modify spray patterns to prevent the contradiction from manifesting, maintaining both wall protection and mixing quality.
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 reduces pre-ignition occurrences, improves engine power output, and lowers exhaust emissions while maintaining fuel economy by optimizing fuel injection strategies based on individual cylinder pre-ignition counts.
Implementation Method 1
adjusting a spray angle of fuel injection to a cylinder based on an indication of pre-ignition
Implementation Method 2
improve charge cooling, thereby reducing the occurrence of pre-ignition in the cylinder
Data Source
AI summary
Methods and systems are provided for addressing cylinder pre-ignition by adjusting a spray angle of fuel injected into a cylinder responsive to an indication of pre-ignition. A spray pattern of fuel injected in the cylinder is varied based on a cylinder pre-ignition count to reduce cylinder wall impingement of injected fuel while improving air-fuel mixing in the cylinder.