Skip-Cycle Fuel Injection for Two-Stroke UAV Engines
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Solution Overview
Problem
Two-stroke fuel injected engines for unmanned aircraft face challenges in cost, complexity, and electrical power consumption, while conventional systems lack efficiency and fuel economy improvements.
Innovation Solution
The implementation of a skip-cycle fuel injection system, pressure sensor-controlled fuel delivery, and a multi-cylinder configuration with fuel injection at or near the transfer ports to balance fuel distribution, reducing electrical consumption and improving fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel injection systems are implemented in two-stroke engines, then fuel economy and engine performance are improved, but cost and complexity increase
Solution Approach 1:
The patent extracts the fuel injection function from a complex continuous injection system and implements it only during specific compression strokes (every nth stroke), removing unnecessary injection events while maintaining fuel economy benefits
Solution Approach 2:
The fuel injection system operates periodically rather than continuously, injecting fuel only during selected compression strokes based on engine conditions, which reduces complexity while maintaining performance improvements
2Productivity
If fuel injection systems are implemented in two-stroke engines, then engine performance is improved, but electrical power consumption increases
Solution Approach 1:
The fuel injection system activates only during specific compression strokes rather than continuously, significantly reducing electrical power consumption while maintaining engine performance benefits during critical operating phases
Solution Approach 2:
The system applies fuel injection partially (only during selected compression strokes) rather than excessively (continuously), achieving sufficient engine performance improvement while minimizing electrical power requirements
3Stability of the object's composition
If multi-cylinder configuration with fuel injection at transfer ports is used, then fuel distribution is balanced, but device complexity increases
Solution Approach 1:
The fuel injection system targets specific locations (transfer ports) in the multi-cylinder engine rather than uniform distribution, creating local fuel enrichment zones that balance overall fuel distribution across cylinders while using a relatively simple injection mechanism
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 results in improved engine performance, reduced manufacturing costs, enhanced fuel economy, and lower brake specific fuel consumption across a wider RPM range, while maintaining fuel-air equivalence ratio and reducing electrical power usage.
Implementation Method 1
a fuel injector configured to deliver fuel to the crankcase
Implementation Method 2
a pressure sensor configured to detect crankcase pressure
Implementation Method 3
The controller is configured to control fuel injection based on the detected crankcase pressure
Implementation Method 4
internal combustion engines
Data Source
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AI summary
Two-stroke, fuel injected internal combustion engines for unmanned aircraft and associated systems and methods are disclosed herein. Engines configured in accordance with embodiments of the disclosure can include, for example, (a) an electronic fuel injection system configured to provide a desired low fuel rate by injecting fuel every nth compression cycle rather than every cycle (so-called "skip-cycle" operation), (b) one or more pressure sensors configured to measure fluctuations in peak crankcase pressure and use such fluctuations to control fuel injection delivery, and (c) a multi-cylinder configuration having a common crankcase with a fuel injection arrangement configured to mitigate or eliminate problems with mixed redistribution.