Fuel Drain Piston Assembly for Combustion Chamber Protection
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Solution Overview
Problem
Combustion engines face issues with fuel remaining in the fuel manifold draining into the combustion chamber upon shutdown, leading to undesirable emissions and operational problems, and existing fuel system configurations are costly, complex, and heavy due to the need for additional components like ecology tanks and parallel drain systems.
Innovation Solution
A fuel system with a fuel delivery flow path, including a heat exchanger and a fuel thermal management valve, and a piston assembly that directs fuel from the fuel manifold to a return conduit in the fuel tank during engine shutdown, utilizing existing conduits and equipment for efficient fuel drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an ecology tank with ejector pump and check valves is used to store fuel after engine shutdown, then fuel drainage from combustion chamber is improved, but system cost, complexity, and weight increase
Solution Approach 1:
The invention extracts and eliminates the ecology tank, ejector pump, and check valves from the fuel system. Instead of using these separate components to manage fuel drainage, the patent uses the existing fuel return line and a simple valve mechanism integrated into the fuel manifold, thereby removing unnecessary components while maintaining fuel drainage functionality.
Solution Approach 2:
The fuel return line, originally designed for thermal management during engine operation, is made multi-functional by enabling it to also serve as the drainage path during shutdown. The valve mechanism allows the same line to switch between thermal management mode and drainage mode, eliminating the need for separate ecology tank and drainage systems.
2Device complexity
If a direct drain line from fuel manifold to fuel tank is implemented, then system complexity is reduced, but check valves and parallel drain systems are still required
Solution Approach 1:
The fuel return line system serves itself by handling both thermal management and fuel drainage functions through a single integrated pathway. The valve mechanism enables the system to automatically switch between functions based on engine operational state, eliminating the need for separate check valves and parallel drain systems.
3Temperature
If fuel thermal management system is added to control fuel temperature, then fuel temperature management is improved, but system weight and complexity increase
Solution Approach 1:
The fuel return line is designed to serve dual purposes: during engine operation, it provides thermal management by returning excess fuel to the tank for cooling; during shutdown, it serves as the drainage path. This multi-functionality eliminates the need for separate thermal management and drainage systems, reducing overall complexity while maintaining temperature control capability.
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 effectively prevents fuel from draining into the combustion chamber, reduces system complexity and weight by eliminating the need for additional components, and ensures efficient fuel management during engine operation and shutdown.
Implementation Method 1
a fuel thermal management system comprising a heat absorption side of a heat exchanger is disposed along the fuel delivery flow path
Implementation Method 2
The engine fuel system is configured to communicate pump discharge pressure to a first side of the piston in response to an engine operating condition to direct the piston to a first position
Data Source
AI summary
An engine fuel system is disclosed for managing drainage of fuel in response to an engine shut-down condition. For normal operation, a piston of a piston assembly is maintained in a first position by pressurized fuel in a volume on a first side of the piston. In response to engine shut-down, pressure is removed from the first side of the piston and fuel in the volume on the first side of the piston is drained into a return conduit that is part of the fuel system's thermal management system. Displacement of the piston in response to removal of pressure on the first side of the piston creates a volume on a second side of the piston for drainage of fuel from a fuel manifold.