Common Rail Return Pipe Layout for Pressure Reducing Valve Lubrication
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Solution Overview
Problem
Existing engine devices with common rails face restrictions in mounting angle and direction of the fuel return pipe, leading to potential abrasion of the pressure reducing valve and limited design freedom due to the need for additional supporting members and protection of fuel injection pipes.
Innovation Solution
The common rail is arranged below the air-intake manifold, with the fuel return pipe extending from the pressure reducing valve to a higher position and then to a lower position, allowing the pressure reducing valve to be soaked in fuel and eliminating the need for additional support members, while the fuel injection pipes pass between the cylinder head and exhaust gas recirculation device for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common rail is mounted at a restricted mounting angle (45 to 90 degrees upward) to ensure fuel lubrication of the pressure reducing valve, then the sliding part of the pressure reducing valve is properly soaked in fuel, but the design freedom and mounting flexibility of the engine device are limited
Solution Approach 1:
The fuel return pipe is configured to extend in multiple directions and positions, specifically extending from the pressure reducing valve to a position higher than the pressure reducing valve and then to a position lower than the pressure reducing valve. This three-dimensional routing allows fuel to reach the sliding part from above through gravity and pressure, enabling proper lubrication regardless of the common rail's mounting angle or orientation.
Solution Approach 2:
The invention changes the parameter of fuel delivery path from a direct horizontal connection to a vertical multi-stage extension. By making the fuel return pipe extend upward first and then downward, the system ensures that fuel can flow to the sliding part through both pressure and gravity assistance, maintaining effective lubrication across varying mounting conditions.
2Reliability
If additional supporting members are added to protect fuel injection pipes from damage, then the reliability of the engine device is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The fuel return pipe is routed to pass between the cylinder head and the exhaust gas recirculation device. By utilizing the existing spatial relationship and structural components already present in the engine device, the fuel injection pipes are naturally protected without requiring additional supporting members. The exhaust gas recirculation device itself serves as a protective barrier.
Solution Approach 2:
The exhaust gas recirculation device serves a dual function: it performs its primary function of recirculating exhaust gas while simultaneously serving as a protective structure for the fuel injection pipes. This eliminates the need for dedicated protective components, reducing overall device complexity.
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 arrangement reduces abnormal abrasion of the pressure reducing valve, enhances design freedom, minimizes manufacturing costs, and protects the fuel injection pipes from damage, resulting in a more compact and reliable engine device.
Implementation Method 1
the fuel return pipe extends from the pressure reducing valve to a position higher than the pressure reducing valve, and then extends to a position lower than the pressure reducing valve. With this, the fuel can be stored between the pressure reducing valve and a portion of the fuel return pipe, which portion positioned higher than the pressure reducing valve
Data Source
AI summary
An engine device including a common rail configured to store, at a high pressure, a fuel supplied by a fuel feed pump. The common rail includes a pressure reducing valve configured to discharge the fuel in the common rail to a fuel return pipe. The fuel return pipe extends from the pressure reducing valve, and then extends to a position lower than the pressure reducing valve.