Internal Combustion Engine Duct Cooling via Pilot Injection
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Solution Overview
Problem
Conventional compressed self-ignition internal combustion engines face overheating issues with fuel ducts, leading to premature evaporation and self-ignition before adequate premixing with charged air, resulting in increased smoke generation and reduced thermal efficiency.
Innovation Solution
The engine employs a control device to adjust the pilot injection parameters, such as reducing the maximum lift amount, increasing the spray angle, and increasing the number of pilot injections, to ensure fuel adheres to the duct's inner wall, utilizing latent heat for cooling and preventing self-ignition, thereby optimizing premixing and reducing smoke generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the duct is arranged suspended in the combustion chamber to promote premixing of fuel and charged air, then premixing is improved, but the duct becomes overheated causing premature evaporation and self-ignition of fuel
Solution Approach 1:
The patent applies preliminary action by performing a pilot injection before the main fuel injection. This preliminary fuel injection creates a cooling effect on the duct through evaporation, lowering the duct temperature before the main fuel spray passes through, thereby preventing premature self-ignition while maintaining effective premixing
Solution Approach 2:
The patent changes the parameter of fuel injection timing by introducing a pilot injection phase before the main injection. This temporal parameter change allows the fuel to be injected at different times, creating a cooling effect that modifies the thermal state of the duct and prevents overheating-related premature ignition
2Power
If the duct temperature is high to maintain combustion efficiency, then combustion performance is improved, but fuel spray self-ignites before premixing with charge air
Solution Approach 1:
The pilot injection serves as a preliminary action that prepares the combustion environment by cooling the duct and creating initial fuel-air mixture, ensuring that when the main fuel spray is injected, the duct temperature is appropriate for controlled combustion rather than premature self-ignition
Solution Approach 2:
The patent implements continuous useful action through multiple injection phases (pilot injection followed by main injection) rather than a single injection event. This continuous process ensures that the duct is continuously cooled and prepared, maintaining reliable combustion timing throughout the operation
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 duct overheating, advances premixing with charged air, reduces smoke generation, and enhances thermal efficiency by cooling the fuel spray and delaying self-ignition, leading to improved combustion performance.
Implementation Method 1
A part of the fuel spray that is injected into the combustion chamber in the pilot injection directly adheres to the inner wall surface of the duct provided inside the cylinder head. The duct is cooled by latent heat of the adhered fuel.
Implementation Method 2
Fuel spray that is injected in the subsequent main injection is effectively cooled in the course of passing through the duct. Premixing with charge air is thus advanced while preventing self-ignition of fuel spray
Data Source
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AI summary
An internal combustion engine includes a fuel injection nozzle provided with a nozzle hole for injecting fuel, the nozzle hole exposed from a cylinder head of the internal combustion engine to a combustion chamber, and a hollow duct, an inlet and an outlet of which are exposed to the combustion chamber. The duct is provided in a manner allowing fuel spray injected from the nozzle hole of the fuel injection nozzle to pass through from the inlet to the outlet. The fuel injection nozzle and the duct are configured such that a part of fuel spray that is injected in pilot injection that is performed before main injection directly adheres to an inner wall surface of the duct.