Pump-Accumulator Injector for High-Pressure Fuel Injection
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Solution Overview
Problem
Conventional common rail (CR) and mechanical unit injector (MUI) fuel systems struggle to achieve higher fuel injection pressures within shorter injection durations, leading to complex and expensive hybrid systems with limited design flexibility and retrofitting capabilities.
Innovation Solution
A fuel system featuring a combination of two types of fuel injectors, one with a pumping portion, accumulator, and nozzle, and another simpler common rail type, allowing for high-pressure fuel injection and flexible engine design, with the first type capable of pumping fuel into the common rail and injecting it into combustion chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional common rail or mechanical unit injector fuel system is used, then the system structure is relatively simple, but it cannot achieve higher fuel injection pressures within shorter injection durations
Solution Approach 1:
The fuel injector is divided into two independent types: pump-accumulator injectors for main injection and common rail injectors for auxiliary injection. This segmentation allows each injector type to be optimized for its specific function, enabling high-pressure short-duration main injection while maintaining system simplicity
Solution Approach 2:
The pump-accumulator injector pre-pressurizes fuel in its internal accumulator during the intake stroke, before the compression stroke begins. This preliminary action enables the injector to deliver high-pressure fuel injection during the power stroke without requiring complex high-pressure pumping mechanisms during the injection phase
2Power
If a hybrid fuel system combining CR and MUI components is used, then higher fuel injection pressure can be achieved, but the system becomes complex and expensive with limited design flexibility
Solution Approach 1:
The pump-accumulator injector performs multiple functions: it acts as both a fuel pump during the intake stroke and as a fuel injector during the power stroke. This multi-functionality eliminates the need for separate pump and injector components, reducing system complexity while maintaining high-pressure injection capability
Solution Approach 2:
The pump mechanism and accumulator are merged into a single integrated injector unit. The pump-accumulator injector combines the pumping portion, accumulator portion, and nozzle portion into one component that can both pressurize and inject fuel, simplifying the overall fuel system architecture
3Power
If a hybrid fuel system combining CR and MUI components is used, then higher fuel injection pressure can be achieved, but design flexibility and retrofitting capabilities are limited
Solution Approach 1:
Different injector types are assigned to different cylinders based on specific performance requirements. Pump-accumulator injectors can be installed in cylinders requiring high-pressure short-duration injection, while common rail injectors serve cylinders with different requirements, allowing optimized local performance throughout the engine
Solution Approach 2:
The system allows dynamic selection and combination of different injector types across multiple cylinders. The fuel system can be configured with varying ratios of pump-accumulator to common rail injectors depending on the specific engine application, providing design flexibility and retrofitting options
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 system achieves high-performance fuel injection with improved flexibility and cost-effectiveness, allowing for shorter injection durations and easier retrofitting of existing engines by separating pumping and injection actions, reducing peak torque and wear on engine components.
Implementation Method 1
a plunger reciprocatingly disposed in the bore
Implementation Method 2
configured to receive fuel pushed from the bore of the pumping portion by the plunger
Implementation Method 3
a valve portion connecting the pumping, nozzle, and accumulator portions
Implementation Method 4
pressurized fuel from the accumulator flows through an injector nozzle and sprays into an associated combustion chamber
Data Source
AI summary
A fuel system is disclosed for use with an engine. The fuel system may have a common rail, a first type of fuel injector fluidly connected to the common rail, and a second type of fuel injector fluidly connected to the common rail. The second type of fuel injector may include a pumping portion having a bore formed therein, and a plunger reciprocatingly disposed in the bore. The second type of fuel injector may also include an accumulator portion fluidly connected to the common rail and configured to receive fuel pushed from the bore of the pumping portion by the plunger, a nozzle portion, and a valve portion fluidly connecting the pumping, nozzle, and accumulator portions.