Common Rail Diesel Injection System with ECU Pressure Control
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Solution Overview
Problem
Current common rail (CR) injection systems for low-power diesel engines are complex, energy-intensive, and prone to leaks, requiring excessive energy and fuel delivery due to high pressures and flow rates, making them inefficient and costly.
Innovation Solution
The use of mini-HP monoblock pumps and low-cost direct-injecting injectors, controlled by an Electronic Control Unit (ECU) via a pressure control valve, with fuel return to the tank, and map-controlled fuel injection to achieve pressures up to 800 bar, utilizing commercially available components and eliminating hydraulic leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If complex solenoid valve-controlled injectors are used in CR systems for diesel engines, then high pressures and flow rates can be achieved, but the system requires significantly larger fuel quantity delivery (4-5 times the engine requirement) and consumes excessive energy
Solution Approach 1:
The patent changes the operating parameters by using a mechanically controlled injector design that operates at optimized pressure levels rather than the excessively high pressures required by solenoid valve systems. The mechanically actuated needle valve responds directly to pressure differential changes, allowing efficient fuel delivery at lower energy input compared to electromagnetic actuation systems.
Solution Approach 2:
The patent replaces the electromagnetic solenoid valve actuation system with a purely mechanical needle valve control mechanism. The injector uses a spring-loaded needle valve that opens and closes based on pressure differential, eliminating the need for electromagnetic fields and reducing energy consumption while maintaining precise fuel metering capability.
2Stress or pressure
If solenoid valve-controlled injectors with leakage oil lines are used, then pressure control is achievable, but the CR system requires excessive fuel delivery capacity and complex hydraulic connections
Solution Approach 1:
The patent extracts and eliminates the leakage oil lines from the injector design. The mechanically controlled injector achieves pressure control through the needle valve mechanism itself, without requiring separate leakage pathways. This simplifies the hydraulic architecture by removing unnecessary connections and components.
Solution Approach 2:
The injector design is self-regulating through its mechanical needle valve and spring system. The pressure control is inherent to the mechanical design, where the needle valve automatically responds to pressure differential changes without requiring external solenoid control or separate leakage lines. The system serves itself through mechanical feedback.
3Stress or pressure
If conventional CR systems for diesel engines are used, then high pressure injection is achieved, but hydraulic leaks are inevitable and reduce system efficiency
Solution Approach 1:
The patent employs a simple, robust needle valve design that can be easily manufactured and replaced if needed. The mechanical components are designed for durability and simplicity, using straightforward sealing mechanisms that are reliable and maintenance-friendly compared to complex solenoid valve assemblies with multiple sealing surfaces.
Solution Approach 2:
By replacing electromagnetic solenoid valves with a mechanical needle valve system, the patent reduces the number of sealing surfaces and potential leak paths. The mechanical design uses simpler sealing arrangements that are more reliable and less prone to degradation from thermal cycling and electromagnetic interference.
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 provides a cost-effective, emission-friendly, and leak-minimized CR system for low-power diesel engines, meeting stringent emission standards with reduced energy consumption and operational complexity.
Implementation Method 1
their magnet arrangements are energized accordingly to actuate the nozzle needle
Implementation Method 2
Two such monoblock pumps supply a rail 2. The monoblock pumps 1 are actuated via their roller tappets 14 by a camshaft (not shown). The monoblock pumps 1 feed a constant quantity into the rail 2
Implementation Method 3
The injection pressure stored in the characteristics map in an electronic control unit 4 is set by the quantity control on the pressure side via a DRV 6
Data Source
Figure 1
AI summary
The invention relates to a common rail (CR) diesel fuel injection system and injectors (3) for operating small diesel engines which only require an injection pressure of up to 800 bar. Uncontrolled tappet-actuated monoblock pumps (1) are used for the CR supply, injectors (3) suitable for leakage-free direct injection are used, and the pressure in the rail (2) is controlled on the pressure side via a pressure control valve (DRV) by means of an electronic control unit (ECU).