Common Rail Fuel Return Line Routing for Valve Lubrication
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Solution Overview
Problem
The traditional mounting angle of the common rail in engine devices restricts the direction of the fuel return pipe, leading to restricted design freedom and potential abnormal abrasion of the pressure reducing valve due to fuel lubrication.
Innovation Solution
The fuel return pipe extends from the pressure reducing valve to a position higher than the valve and then to a position lower than the valve, allowing the pressure reducing valve to be soaked in fuel, and the common rail is arranged below the air-intake manifold, eliminating the need for additional support members and protecting the fuel injection pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the common rail is mounted at a traditional mounting angle (45 to 90 degrees upward), then the fuel return pipe can be connected properly, but the design freedom is restricted and the mounting condition is constrained
Solution Approach 1:
The fuel return pipe is configured to extend in a vertical direction (upward) from the pressure reducing valve, then turn and extend in a horizontal direction. This two-dimensional path allows the pipe to connect properly regardless of the common rail's mounting angle, eliminating the constraint that previously required specific mounting angles for proper connection.
2Ease of manufacture
If the fuel return pipe is attached upward to the fuel return pipe connecting part, then the connection is simplified, but the pressure reducing valve may not be properly soaked in fuel leading to abnormal abrasion
Solution Approach 1:
The fuel return pipe is configured to extend vertically upward from the pressure reducing valve before turning horizontal. This vertical extension creates a fuel reservoir effect, allowing fuel to accumulate and soak the pressure reducing valve, thereby preventing abnormal abrasion while maintaining connection simplicity.
3Manufacturing precision
If additional support members are added to hold the fuel return pipe, then the pipe positioning is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The exhaust gas recirculation device serves a dual function: it recirculates exhaust gas and simultaneously acts as a support structure for the fuel return pipe. The fuel return pipe is attached to the exhaust gas recirculation device, eliminating the need for separate support members and 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 configuration reduces abnormal abrasion of the pressure reducing valve, enhances design freedom, and prevents fuel leakage by protecting the fuel injection pipe, while maintaining a compact and cost-effective engine design.
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
Implementation Method 2
A common rail stores, at a high pressure, a fuel supplied from a fuel feed pump. The fuel discharged through the pressure reducing valve is returned to the fuel tank through a fuel return pipe connected to the pressure reducing valve. 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. This can achieve a state where the pressure reducing valve is soaked in the fuel, and can suppress or reduce abnormal abrasion of the sliding part of 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 to a position higher than the pressure reducing valve, and then extends to a position lower than the pressure reducing valve.