Injection rate of cylinder lubrication oil in large two-stroke marine diesel engines using a common rail lubrication system (2307.03408v1)

Abstract: This paper investigates a common rail cylinder lubrication system for large two-stroke marine diesel engines using electronically controlled injectors. The system is studied using the Bosch rate of injection measurement technique The common rail injector has a buildup of mass flow of approximately 1 ms as the injector opens until the nozzle is choked from cavitation. Using a highly viscous fluid, the Bosch rate of injection method is able to predict the injected amount with an error of 5% or lower for nearly the entire tested delivery range of 2 mg to 21 mg. Lubrication of cylinder liners and piston rings is a crucial parameter in operating a two-stoke marine diesel engine efficiently. Both over and under lubrication is harmful for the engine, so the ability to accurately dose the cylinder oil is very important. A mass flow build up time of 1 ms promises high accuracy of dosage even down to 2.5 mg per injection. This paves the way for injecting the oil where and when it is needed, which in turn will improve engine performance and lower harmful emissions.

• The paper demonstrates the application of the Bosch ROI method for measuring high-viscosity lubricant injection with an average prediction error below 5%.
• It reveals rapid mass flow buildup and cavitation-induced choking within 1 millisecond, ensuring efficient atomization and coverage on the cylinder liner.
• The study highlights that electronically-controlled injection provides precise lubrication dosing, down to 2.5 mg, thereby reducing emissions and improving engine efficiency.

Injection Rate of Cylinder Lubrication Oil in Large Two-Stroke Marine Diesel Engines

The paper evaluates the injection rate of cylinder lubrication oil in large two-stroke marine diesel engines, specifically utilizing a common rail lubrication system with electronically controlled injectors. This paper is particularly significant due to the increasing environmental regulations aiming to reduce particulate emissions from marine vessels, where cylinder lubrication oil contributes substantially to such emissions.

Research Methodology

The researchers employed the Bosch Rate of Injection (ROI) measurement technique to paper the lubrication system, which utilizes the principle of propagating pressure waves within a tube to quantify the rate of fluid injection. The methodology necessitated adjustments to apply to marine engine lubricants that typically exhibit higher viscosity compared to standard fuels. The paper validated the methodology via controlled experiments, measuring injection amounts over a set range, and comparing predicted versus actual injected masses with an average prediction error rate of less than 5%.

Key Findings

1. Mass Flow Dynamics: The system exhibits a rapid buildup of mass flow within approximately 1 millisecond before cavitation-induced choking occurs at the nozzle. This is necessary for atomizing the high-viscosity lubricant and capitalizes on the swirl injection principle for effective coverage on the cylinder liner.
2. Injection Control Accuracy: The experimental design ensures accurate dosage control, facilitating precise injection amounts through an electronically-governed setup. The validated Bosch ROI method demonstrates efficacy in predicting the delivered amount of lubricant, supporting operational control down to as low as 2.5 mg per injection.
3. Efficiency and Environment: The potential for optimizing lubrication through precise control of injection times and amounts contributes to efficiency improvements in engine performance and the reduction of particulate emissions.

Implications and Future Directions

The research holds both practical and theoretical implications for maritime diesel engine operation. Practically, the findings support advancements in electronically-controlled lubrication systems that promise operational cost reductions through optimized lubricant consumption. Theoretically, the successful adaptation of the Bosch ROI method for high-viscosity applications advances understanding of injection dynamics in non-standard fluids.

Future research could explore further optimization of the control algorithms for lubrication systems, and development of real-time monitoring and feedback mechanisms could enhance system responsiveness to engine operating conditions. Additionally, adapting these findings to alternative biodegradable lubrication oils may align lubrication technology with environmental conservation efforts.

In conclusion, this paper makes a substantive contribution to the understanding of cylinder lubrication systems in marine diesel engines. The research not only provides a validated approach for measuring and controlling lubrication oil injection but also signifies a step forward in meeting stringent emission regulations while maintaining or enhancing engine efficiency.