Uniflow Two-Stroke Engine Fuel Injection Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In uniflow scavenging two-cycle engines, there is a delay in stopping the injection of fuel gas after the control valve is closed, leading to incomplete cessation of fuel gas injection.
Innovation Solution
The engine employs a fuel injecting unit with an inner and outer pipe configuration, where the inner pipe and outer pipe overlap to form a double pipe, allowing the fuel gas injection to be rapidly stopped by changing their relative positions based on hydraulic pressure differences, ensuring no fuel gas leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a control valve is used to stop fuel gas injection, then the injection can be stopped, but there is a delay and fuel gas continues to leak after the valve closes
Solution Approach 1:
The fuel injection path is segmented into multiple sections using an inner pipe and outer pipe structure. The inner pipe can be independently moved to close the injection opening, separating the control function from the fuel path and enabling immediate shutdown without delay.
Solution Approach 2:
The inner pipe is made movable relative to the outer pipe, allowing dynamic adjustment of the injection opening. By moving the inner pipe to cover the outer pipe's opening, the system achieves rapid closure of the fuel gas path, eliminating the delay inherent in traditional valve mechanisms.
2Productivity
If fuel gas is injected through a chamber and nozzle pipe, then fuel gas can be supplied into the cylinder, but fuel gas leakage occurs after the control valve closes
Solution Approach 1:
The harmful effect of fuel gas leakage is extracted and eliminated by introducing a movable inner pipe that can independently close the injection opening. This inner pipe acts as a separate control element that directly blocks the fuel path, preventing leakage without affecting the overall fuel supply efficiency.
Solution Approach 2:
The inner pipe serves as an intermediary element between the fuel supply system and the injection opening. It provides an additional control layer that can rapidly block the fuel path by moving to cover the outer pipe's opening, thereby preventing fuel gas leakage while maintaining normal injection operation.
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 enables immediate cessation of fuel gas injection without delay, maintaining a consistent mixture concentration and preventing fuel gas leakage.
Implementation Method 1
a hydraulic press that moves the inner pipe
Implementation Method 2
utilizing a pressure difference between a scavenging port side and the other side
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A uniflow scavenging two-cycle engine includes: a cylinder in which a combustion chamber is formed; a piston that slides in the cylinder; a scavenging port that is provided one end side of the piston in a stroke direction in the cylinder and suctions active gas in the combustion chamber in response to a sliding motion of the piston; and a fuel injecting unit (126) that is provided on an outer side of the cylinder in a radial direction from the scavenging port and injects fuel gas into the active gas which is suctioned into the scavenging port. The fuel injecting unit includes an inner pipe (156) which has an inner hole penetrating between an inside and an outside thereof and through which fuel gas is guided to the inside, an outer pipe (158) which has an outer hole penetrating between an inside and an outside thereof and stows the inner pipe in the inside thereof so as to form a double pipe with the inner pipe, and a driving unit (154) which changes relative positions of the inner pipe and the outer pipe and changes an opening amount as an area of an overlap between the inner hole and the outer hole.