Dual Injector Two-Stroke Engine Fuel System
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Solution Overview
Problem
Two-stroke endothermic engines face challenges in achieving a homogeneous air-fuel mixture and high power output while minimizing noxious emissions and fuel consumption, particularly due to limitations in fuel injection systems and the mixing of lubricants with fuel, leading to increased unburnt hydrocarbons and carbon emissions.
Innovation Solution
The engine design incorporates two injectors positioned downstream of a lamellar pack in the intake duct, with one injector spraying fuel downwards and the other upwards, allowing for delayed fuel injection and independent electronic control, ensuring efficient mixing and lubrication, and eliminating the need for a separate lubricant circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single injector is used in two-stroke engines, then the device complexity is reduced, but the power output and fuel injection quantity are limited
Solution Approach 1:
The single injector is segmented into two separate injection nozzles (first and second nozzles) with different spray directions. The first nozzle sprays fuel toward the exhaust port side while the second nozzle sprays fuel toward the transfer port side, allowing both nozzles to operate simultaneously and increase total fuel injection quantity without requiring multiple injector units, thus maintaining simplicity while boosting power output.
2Stability of the object's composition
If injectors are arranged symmetrically with respect to the exhaust port, then fuel distribution is improved at high revolutions, but unburnt hydrocarbon emissions increase due to streams meeting in the middle zone
Solution Approach 1:
The two injection nozzles are arranged asymmetrically with respect to the exhaust port. The first nozzle is positioned on one side spraying toward the exhaust port side, while the second nozzle is positioned on the opposite side spraying toward the transfer port side. This asymmetric arrangement prevents fuel streams from meeting in the middle zone near the exhaust port, reducing unburnt hydrocarbon emissions while maintaining good fuel distribution at high revolutions.
3Power
If injector opening time is increased to inject more fuel, then power output is improved, but the risk of fresh mixture leakage increases
Solution Approach 1:
The control system operates the two nozzles in a coordinated periodic manner based on engine operating conditions. At high revolutions, both nozzles are activated simultaneously for brief periods to maximize fuel injection. At low revolutions, only one nozzle is activated to reduce the risk of fresh mixture leakage. This periodic, condition-based operation allows the system to achieve high power output when needed while minimizing harmful effects during normal operation.
4Device complexity
If lubricant is added to fuel for two-stroke engine lubrication, then the lubrication system is simplified, but unburnt fuel percentage is impaired by lubricant residues
Solution Approach 1:
The asymmetric nozzle arrangement creates different local fuel distribution patterns in the combustion chamber. The first nozzle directs fuel toward the exhaust port side while the second nozzle directs fuel toward the transfer port side, creating zones with different fuel-lubricant mixture characteristics. This local quality variation helps separate lubricant residues from the main fuel charge, reducing their impact on unburnt hydrocarbon emissions while maintaining the simplified lubrication system.
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 reduces emissions and fuel consumption, enhances power output by ensuring a lean air-fuel mixture during low engine loads and achieving maximum power through progressive fuel injection, while minimizing fuel losses and the need for additional lubrication systems.
Implementation Method 1
two injectors, one of which sprays fuel in the duct and orients it toward the axis of the cylinder and downwards, whereas the other sprays fuel toward the axis of the cylinder and upwards
Implementation Method 2
achieving a homogeneous air-fuel mixture
Implementation Method 3
downstream of a lamellar pack in the intake duct
Implementation Method 4
spark controlled-ignition type
Data Source
AI summary
An electronic injection two-stroke endothermic engine comprising an upper fuel injector (13) and a lower fuel injector (14), both accommodated in an intake duct (12) directly facing the cylinder (1), the latter closed by a head to form a combustion chamber (6) with one or more spark plugs (5) and connected to a pump-crankcase underneath via a plurality of side transfer ports (7, 8) which a central transfer port (15) is added to and crosses said intake duct (12) and allows the fuel sprayed by said lower injector (14) to reach the inside of the cylinder (1).