Controlled Nozzle Injection for High-Pressure Fuel Atomization
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Solution Overview
Problem
Internal combustion engines with mechanical fuel delivery systems face inefficiencies leading to incomplete combustion and increased pollution due to low pressure at the nozzle, resulting in larger fuel droplets that do not fully evaporate and mix with air, causing increased particulates, smoke, and hydrocarbons.
Innovation Solution
A controlled nozzle injection apparatus that uses a high pressure manifold to accumulate and recycle residual fuel, maintaining elevated pressures throughout the fuel delivery cycle by bootstrapping pressurized fuel back into the system, and incorporating a control valve to dynamically control pressure, ensuring higher opening and closing pressures at the nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a mechanical pump is used for fuel delivery, then the system cost is reduced, but the fuel injection pressure is insufficient leading to incomplete combustion
Solution Approach 1:
The system pre-pressurizes the fuel delivery line using the mechanical pump before injection occurs. The pump builds up pressure in advance during the compression stroke, ensuring high pressure is available when the injector valve opens, eliminating the need for expensive high-pressure electronic pumps while maintaining effective injection pressure.
Solution Approach 2:
The mechanical pump operates periodically in synchronization with the engine cycle, delivering fuel pulses that build pressure in the delivery line. This periodic pressurization occurs at optimal moments in the combustion cycle, maintaining high pressure without requiring continuous expensive high-pressure pumping systems.
2Device complexity
If fuel is injected at low pressure, then the mechanical pump operation is simpler, but larger fuel droplets are produced that do not evaporate and mix completely
Solution Approach 1:
The system prepares the fuel by pre-pressurizing it in the delivery line before it reaches the injector. This preliminary pressurization ensures that when the injector valve opens, the fuel is already at high pressure, enabling fine atomization and complete combustion without requiring complex high-pressure pump mechanisms.
3Ease of operation
If residual fuel is vented from the nozzle, then pressure control is simpler, but fuel delivery efficiency is reduced
Solution Approach 1:
The system eliminates the need for separate residual fuel venting mechanisms by designing the injector valve to close automatically when combustion chamber pressure exceeds delivery line pressure. The fuel system serves itself by using the natural pressure differential to control injection termination, maintaining efficiency without complex venting operations.
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 solution ensures more complete combustion of fuel, reducing pollutants and maintaining high pressures at the nozzle, thereby decreasing emissions and improving fuel delivery efficiency without significant additional expense.
Implementation Method 1
A controlled nozzle injection apparatus which utilizes a high pressure manifold to accumulate pressurized fuel from a fuel pump
Implementation Method 2
a control valve in fluid communication with the nozzle, wherein the control valve dynamically and selectively controls a pressure of the pressurized fuel within the injection conduit
Implementation Method 3
The nozzle of the fuel injector 16 operates to atomize the fuel as it enters the high pressure air combustion chamber of the engine
Data Source
AI summary
A nozzle injection apparatus for use in internal combustion engines includes a fuel pump for intermittently pressurizing fuel, an injection conduit in fluid communication with the fuel pump, the injection conduit permitting the pressurized fuel to be communicated to a fuel injection nozzle a control valve in fluid communication with the nozzle, wherein the control valve dynamically and selectively controls a pressure of said pressurized fuel within the injection conduit.