Stepped Piston Check Valve for Fuel System Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel system check valves contribute to evaporative emissions during diurnal heating and cooling cycles due to pressure fluctuations, leading to unintended fuel discharge from fuel injectors, and existing solutions fail to effectively manage pressure and reduce energy consumption.
Innovation Solution
A check valve with a stepped piston design that limits fuel flow and maintains the valve closed during diurnal conditions, opening only with a low pressure difference to minimize power consumption and prevent fuel from entering the fuel rail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a check valve is configured to open at a low pressure differential to reduce fuel pump energy consumption, then the fuel pump consumes less energy, but the check valve opens during diurnal cooling cycles allowing fuel to enter the fuel rail and contribute to evaporative emissions
Solution Approach 1:
The check valve is segmented into two distinct stages: a first stage with a larger diameter that opens at a higher pressure differential to prevent fuel flow during diurnal cooling, and a second stage with a smaller diameter that opens at a lower pressure differential to allow fuel flow during normal operation. This segmentation allows the valve to perform different functions at different pressure conditions, resolving the contradiction between energy efficiency and emission control.
Solution Approach 2:
The invention changes the pressure differential parameter at which the valve opens by providing two different opening pressure differentials through the two stages. The first stage opens at a first pressure differential (higher) and the second stage opens at a second pressure differential (lower). This parameter change allows the system to adapt to different operating conditions, preventing emissions during diurnal cooling while maintaining energy efficiency during normal operation.
2Loss of time
If a check valve is installed to maintain fuel rail pressure and reduce engine start time, then engine restart time is reduced, but the check valve allows fuel flow during diurnal heating and cooling cycles contributing to evaporative emissions
Solution Approach 1:
The check valve is divided into two stages with different opening characteristics. The first stage with larger diameter provides the primary pressure maintenance function for quick engine restart by opening at a higher pressure differential to prevent fuel flow during diurnal cooling. The second stage with smaller diameter provides a secondary function to allow controlled fuel flow at lower pressure differentials, preventing excessive pressure buildup during diurnal heating while minimizing emissions.
Solution Approach 2:
Different parts of the check valve have different properties: the first stage has a larger diameter and opens at a higher pressure differential for pressure maintenance, while the second stage has a smaller diameter and opens at a lower pressure differential for emission control. This local quality differentiation allows each part to optimize for its specific function, resolving the contradiction between quick restart capability and emission prevention.
3Reliability
If a conventional check valve is used to prevent fuel backflow, then fuel pressure is maintained, but the valve cannot effectively control pressure fluctuations during diurnal heating and cooling cycles
Solution Approach 1:
The check valve is segmented into two stages that respond to different pressure conditions. The first stage handles high pressure differential conditions (such as during fuel pump operation or rapid temperature changes) by opening at a higher pressure differential to maintain reliable pressure control. The second stage handles low pressure differential conditions (such as during diurnal cooling cycles) by opening at a lower pressure differential to adapt to subtle pressure fluctuations. This segmentation provides both reliability and adaptability.
Solution Approach 2:
The check valve dynamically adapts its opening pressure differential based on operating conditions through the two-stage design. Rather than a fixed opening pressure, the valve can open at either the first or second pressure differential depending on which stage is activated. This dynamic behavior allows the valve to maintain reliable pressure control across varying operating conditions while adapting to diurnal heating and cooling cycles, resolving the contradiction between reliability and adaptability.
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
Reduces evaporative emissions, enhances fuel pump efficiency, and simplifies fuel system design by controlling pressure fluctuations and preventing fuel discharge during diurnal cycles.
Implementation Method 1
the check valve may be held open with very little pressure difference across the valve so that power consumption of a fuel pump may be reduced
Data Source
AI summary
A fuel line check valve system and a fuel system that includes the fuel line check valve system are described. The fuel line check valve system may prevent flow into a fuel system that is generated via a vacuum in the fuel system. The fuel line check valve system may also remain in an open state after it is open via a reduced pressure.