Bi-Fuel Engine Pressure Switch Valve Design
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Solution Overview
Problem
Existing bi-fuel engines require users to manually operate multiple valves to select between liquid and gas fuels, which is inconvenient and prone to errors, and also incur additional costs due to the need for leak-proof valves.
Innovation Solution
A bi-fuel engine design that uses a pressure supply passage with a switch valve to selectively supply either gas fuel or liquid fuel by actuating the gas fuel on/off valve and liquid fuel pump, eliminating the need for additional on/off valves and simplifying the structure to prevent fuel leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manually operated valves are provided in both gas fuel supply passage and liquid fuel supply passage to shut off undesired fuel, then fuel supply can be controlled, but user operation becomes inconvenient and complex
Solution Approach 1:
The invention extracts the on/off control function from the fuel supply passages and relocates it to the pressure supply passage. By placing the switch valve in the pressure supply passage that feeds both the gas fuel on/off valve and liquid fuel pump, the control function is separated from the fuel pathways, simplifying user operation to a single valve while maintaining reliable fuel supply control.
Solution Approach 2:
The pressure supply passage serves multiple functions: it supplies pressure to both the gas fuel on/off valve and the liquid fuel pump, and contains the switch valve that controls both fuel supply lines. This multi-functional design eliminates the need for separate control valves in each fuel passage, reducing operational complexity while ensuring reliable fuel control.
2Reliability
If manually operated valves are provided in fuel supply passages to shut off undesired fuel, then fuel supply can be controlled, but the number of components and cost increase
Solution Approach 1:
The control function is extracted from the fuel supply passages and concentrated in a single switch valve located in the pressure supply passage. This eliminates the need for multiple valves in parallel fuel lines, reducing component count while maintaining the ability to control both gas and liquid fuel supply reliably.
Solution Approach 2:
The invention merges the control of both gas and liquid fuel supply into a single switch valve by positioning it in the common pressure supply passage. This consolidation reduces the total number of valves from two (one in each fuel line) to one, simplifying the overall device structure while preserving fuel supply control functionality.
3Reliability
If valves are required to be free from leakage to ensure proper operation, then fuel supply control is reliable, but manufacturing cost increases
Solution Approach 1:
The pressure supply passage acts as an intermediary medium to control fuel supply. By placing the switch valve in the pressure passage rather than directly in the fuel lines, the valve handles clean pressurized gas rather than fuel, significantly reducing leakage risks and simplifying manufacturing requirements while maintaining reliable fuel supply control.
Solution Approach 2:
The valve is extracted from the fuel environment and relocated to the pressure supply passage. This separation means the switch valve operates on clean compressed air or inert gas rather than fuel, eliminating the need for expensive fuel-tight sealing requirements and associated manufacturing costs while preserving control reliability.
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
Enables easy and reliable selection between fuels with a simple, cost-effective valve system, minimizing the risk of fuel leakage and reducing the number of components, thus enhancing user convenience and engine efficiency.
Implementation Method 1
a pressure source (4) of the engine, and branching into a first branch passage (35B) and a second branch passage (35C) at a branching portion
Implementation Method 2
a gas fuel on/off valve (28) provided in the gas fuel supply passage and connected to the first branch passage so that the gas fuel supply passage may be opened when pressure is supplied to the gas fuel supply passage, and may be closed when pressure is not supplied to the gas fuel supply passage
Implementation Method 3
a liquid fuel pump (33) provided in the liquid fuel supply passage and configured to feed the liquid fuel under pressure to the intake system by a pulsating pressure supplied via the second branch passage
Implementation Method 4
a switch valve provided in the branching portion to switch between the first branch passage and the second branch passage for conducting pressure supplied from the pressure source via the pressure supply passage
Data Source
AI summary
Provided is a bi-fuel engine including a pressure supply passage extending from a crankcase chamber, and branching into a first branch passage and a second branch passage at a branching portion, a gas fuel valve provided in the gas fuel supply passage and connected to the first branch passage so that the gas fuel supply passage may be opened when pressure is supplied to the gas fuel supply passage, and may be closed when pressure is not supplied to the gas fuel supply passage, a liquid fuel pump provided in the liquid fuel supply passage and configured to feed the liquid fuel under pressure to the intake system by a pulsating pressure supplied via the second branch passage, and a switch valve provided in the branching portion to switch between the first and second branch passages for conducting pressure supplied from the pressure source via the pressure supply passage.