Lubricating Oil Dosing Timing in Two-Stroke Marine Engines
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Solution Overview
Problem
Current lubricating oil delivery systems in two-stroke diesel engines, particularly marine engines, do not effectively adjust the timing of lubricating oil delivery based on engine load, leading to suboptimal lubrication and increased emissions, as they rely on fixed timing irrespective of engine load and exhaust valve closing time.
Innovation Solution
A method and system that adjust the timing and amount of lubricating oil delivery in two-stroke diesel engines based on actual engine load and exhaust valve closing time, using electronic control to synchronize lubricating oil delivery with the engine's operational profile, allowing for load-dependent optimization of lubricating oil usage and emission reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed timing of lubricating oil delivery is used irrespective of engine load, then the system structure remains simple, but lubrication effectiveness deteriorates and emissions increase
Solution Approach 1:
The patent implements dynamic adjustment of lubricating oil delivery timing based on exhaust valve closing time and engine load conditions. The control system continuously varies the injection timing angle relative to TDC (top dead center) according to operating conditions, transforming the static fixed-timing system into a dynamic adaptive system that optimizes lubrication effectiveness across different engine loads.
Solution Approach 2:
The control system uses feedback from exhaust valve closing time detection and engine load sensing to automatically adjust the lubricating oil delivery timing. The electronic control unit receives information about the actual valve closing moment and modifies the injection timing accordingly, creating a closed-loop control system that maintains optimal lubrication without requiring complex manual calibration.
2Manufacturing precision
If lubricating oil is delivered before piston passage using air swirl, then oil distribution on cylinder wall improves, but timing must be precisely coordinated with exhaust valve closing
Solution Approach 1:
The system delivers lubricating oil to the cylinder wall before the piston passes the injection units, utilizing the air swirl generated during the exhaust phase. This preliminary injection allows the oil to be distributed on the cylinder wall by the air flow and subsequent piston movement, achieving uniform coverage without requiring complex in-cylinder injection mechanisms.
Solution Approach 2:
The exhaust valve closing time serves as an intermediary reference point that mediates between the air swirl generation and oil injection timing. By using the valve closing event as the synchronization基准, the system coordinates the complex interaction between air flow patterns and oil delivery without requiring direct sensing of air swirl or complex multi-parameter control.
3Object-generated harmful factors
If exhaust valve closing time is adjusted for emission reduction, then NOx and smoke emissions decrease, but lubricating oil delivery timing becomes misaligned
Solution Approach 1:
The system dynamically adapts lubricating oil delivery timing to match varying exhaust valve closing times. As the valve closing angle is adjusted for different emission targets and engine loads, the oil injection timing automatically synchronizes accordingly, maintaining the optimal relationship between air swirl generation and oil delivery across the entire operating range.
Solution Approach 2:
The control system changes the injection timing parameter in direct response to exhaust valve closing time adjustments. When the valve closing angle is modified to reduce emissions or optimize performance, the system proportionally adjusts the oil delivery timing angle relative to TDC, ensuring that lubrication effectiveness is maintained despite changes in emission control parameters.
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 approach enhances the utilization of lubricating oil, reduces emissions, and allows for optimal air swirl distribution, ensuring efficient lubrication while minimizing lubricating oil usage across varying engine loads and operational profiles.
Implementation Method 1
the air swirl formed within the cylinder during the exhaust phase is used for assisting distribution of an atomised lubricating oil on the cylinder wall. The air swirl therefore contributes to transporting oil droplets onto the cylinder wall
Implementation Method 2
distribution of an atomised lubricating oil on the cylinder wall
Data Source
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AI summary
There is disclosed a system for dosing lubricating oil into cylinders, preferably in twostroke diesel engines, for example marine engines. The system includes: - injection units (251) provided in the walls (57) of the cylinders as a number of injection units are used for each cylinder; - a lubricating apparatus (252) for delivering a dosed amount of lubricating oil under pressure to the injection units; - means (56) for detecting the load of the engine; - an exhaust valve (55) connected to an actuator (53) for displacing the exhaust valve; and - a control unit (50) for electronic control and timing of the closing time of the exhaust valve of the cylinder, depending on detection of the engine load, as a signal is transmitted to the actuator, and as an adjustment of the closing time of the exhaust valve in relation to the actual engine load is performed. The control unit is also adapted to electronic control and timing of the lubricating oil delivery. In order to possibly improve engine emission and enhance utilisation of the lubricating oil, the system further includes: - a connection (44) between the means (56) for detecting the engine load and the control unit (50) for transferring the detected data; and - a connection (43) between the control unit (50) and the lubricating apparatus (252) for transferring a control signal to the lubricating apparatus for adjusting the timing of the lubricating oil delivery in dependence of the engine load.