High-Pressure Common Rail Safety Valves for Low-Speed Engines
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Solution Overview
Problem
High-pressure common rail systems for low-speed engines lack comprehensive safety protection functions, leading to potential failures due to high-pressure conditions and stringent reliability requirements.
Innovation Solution
A high-pressure common rail system incorporating an electronic control unit, electronic control high-pressure fuel pump, flow limiting valves, pressure limiting valves, shut-off valves, safety valves, and circulation valves, which work together to manage fuel pressure and prevent excessive leakage, ensuring safe operation and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-pressure common rail systems are used to meet emission regulations and fuel economy requirements, then injection pressure and response speed are improved, but system reliability and safety requirements become more stringent due to constant high-pressure state
Solution Approach 1:
The system divides the high-pressure fuel supply into multiple independent zones with separate control valves (first shut-off valve, second shut-off valve, third shut-off valve) positioned at different locations (fuel pump outlet, distribution block, common rail). This segmentation allows localized pressure control and isolation, preventing total system failure and improving reliability while maintaining high injection pressure.
Solution Approach 2:
Multiple safety valves (first safety valve, second safety valve, third safety valve) are introduced as intermediary protection devices that automatically activate when pressure exceeds safe thresholds. These valves serve as mediators between the high-pressure fuel system and potential failure modes, releasing excess pressure to protect the system while allowing normal high-pressure operation during intended use.
2Reliability
If multiple safety protection functions are implemented in the high-pressure common rail system, then system reliability is improved, but device complexity increases due to multiple valves and control mechanisms
Solution Approach 1:
The ECU integrates multiple control functions into a single electronic control unit, managing all shut-off valves, safety valves, and circulation valves through unified software control. This multi-functionality approach reduces mechanical complexity by consolidating control logic while maintaining multiple safety functions. The circulation valve also serves dual purposes: preventing fuel stagnation during normal operation and enabling system drainage during shutdown.
Solution Approach 2:
The system combines multiple safety functions into integrated valve assemblies where shut-off valves and safety valves work together in coordinated fashion. The circulation system is merged with the main fuel supply line, allowing the same pipeline to serve both fuel delivery and fuel circulation/drainage functions, thereby reducing the need for completely separate safety systems.
3Reliability
If circulation valves are opened when the low-speed engine is stopped to form circulation loops, then fuel stagnation is prevented, but fuel pressure control becomes more complex
Solution Approach 1:
The circulation valve operates periodically based on engine operational state rather than continuously. It automatically opens when the engine stops to prevent fuel stagnation and closes when the engine runs to maintain normal pressure delivery. This periodic action is controlled by simple state-based logic in the ECU, avoiding the need for complex continuous pressure regulation mechanisms while still achieving reliable fuel circulation when needed.
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 effectively stabilizes fuel pressure, prevents excessive leakage, and ensures safe operation by implementing multiple safety protection functions, enhancing the reliability and safety of the high-pressure common rail system for low-speed engines.
Implementation Method 1
the flow limiting valve component is configured to be closed when a fuel pressure difference between the fourth high-pressure fuel pipe and the common rail pipe exceeds a set pressure difference
Implementation Method 2
the pressure limiting valve component is configured to be opened when the fuel pressure in the common rail pipe exceeds a first set pressure value, so that the fuel pressure in the common rail pipe is stabilized at a target pressure value
Implementation Method 3
the safety valve component is configured to be opened when the shut-off valve component and the pressure limiting valve component malfunction and the fuel pressure in the common rail pipe exceeds a second set pressure value
Data Source
Figure 1
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AI summary
The present solution provides a high-pressure common rail system for a low-speed engine with multiple safety protection functions to achieve the multiple safety protection functions of the high-pressure common rail system. The system comprises: an ECU; an electronic control high-pressure fuel pump provided with an electronic control proportional valve configured to adjust the rate of feed of a low-pressure heavy fuel oil from a fuel tank of the low-speed engine into the electronic control high-pressure fuel pump according to a first instruction from the ECU; a first distribution block connected to the electronic control high-pressure fuel pump via a first high-pressure fuel pipe; a second distribution block connected to the first distribution block via a second high-pressure fuel pipe; and a common rail pipe connected to the second distribution block via a third high-pressure fuel pipe. A sensor connected to the ECU is mounted onto the common rail pipe. A plurality of flow limiting valve components are mounted onto the common rail pipe, and each of the flow limiting valve components is connected to one of electronic control fuel injectors via one of fourth high-pressure fuel pipes. A pressure limiting valve component is further mounted onto the common rail pipe. The first distribution block is equipped with a shut-off valve component and a safety valve component. Circulation valve components are further mounted onto the common rail pipe and onto each electronic control fuel injector.