New system heralds step change in cylinder lubrication

Hans Jensen Lubricators has launched a new lubrication solution that eliminates the need for cylinder lubrication pumps and offers a significant reduction in cylinder lubricant oil consumption rates.

The new HJ Smartlube 4.0 solution represents the culmination of years of research into how to improve the efficiency of cylinder lubrication systems for two-stroke engines, while lowering operational costs.

Stefan Nielsen, chief commercial officer at Hans Jensen Lubricators discussed how the system had been designed with flexibility as a goal. “Our new product, HJ Smartlube 4.0 has the highest flexibility of any lubrication system available. Not only in terms of the advantages the technology brings in regards to main engine lubrication performance – but also how the system is based on a modular approach, where we started our design and succeeded with the ambition of making the most optimum cylinder lubrication technology for two-stroke engines, perfect for both newbuilding and retrofit projects.”

Current cylinder lubrication systems typically feature an oil station, a cylinder lubrication pump, and an injection valve. The new HJ Smartlube 4.0 operates without a lubricator through a single high-pressure cylinder lube oil line, removing the need for cylinder lubrication pumps. This is possible by making the injection valves electronic.

By supplying high pressure oil to all lube points simultaneously, the ability to inject lube oil has been moved up-stream into the cylinder lubricator injection valves. In effect, the valve now works as the lubricator itself, determining the timing as well as the duration of the opening.

The rationalisation of the installation has a number of economic advantages, as the time and components required for the system have been reduced, lowering CAPEX costs. In addition, the technology offers significant OPEX reductions, by potentially reducing CLOC and cylinder liner wear, which is expected to be reflected in time between overhauls (TBO).

The company itself believes that the new product represents a significant advance in cylinder lubrication. Nikolaj Kristensen, Hans Jensen Lubricators Head of R&D likened the potential impact of the new system to the introduction of common rail fuel injectors. “We believe that this system is the future of cylinder lubrication: it offers more advanced and flexible control, consistent oil injection, all achieved with an overall simpler system, while minimising cylinder oil consumption, and optimising the cylinder condition.”

Smart Algorithms

The solution includes three different load-dependent feed rate regulation options to optimise cylinder liner conditions.

The direct control of the valves means that the system can provide more accurately timed injections, while very small amounts can be injected while maintaining spray quality.

The first of the algorithms, Multi Timing, uses the valves ability to inject oil more than once per revolution, and even divide the oil between different injections, all during the same engine revolution.

For example, the majority of the cylinder lubricant could be injected via SIP (swirl injection principle), in which the cylinder lube oil is vaporised in the high-pressure air and distributed on a large area of the upper liner surface just before the piston passes, and 20% of the lubricant could be equally divided between the ring-pack compression and combustion strokes.

Another of the options, Automatic Cleaning Cycle, optimises cylinder lubrication feed rates over a 24-hour period to ensure that the feed rate reaches a high enough level for the cylinder lubricant to clean the cylinder.

The increased flexibility offered by the HJ Smartlube 4.0 system is important because the lower sulphur oils being used since IMO 2020 took effect tend to have a lower lubricity, but intermittent higher feed rates can make use of lubricants’ detergency without sacrificing CLOC efficiencies.

A third algorithm, Delta timing, allows for optimum distribution and quantity at any given instance, providing automatic and full control over how much and where the cylinder oil is introduced in the cylinder.

Internet of Things

In addition to applying algorithms to optimise the operation of the system, the new system will also be compatible with a new IoT module that Hans Jensen Lubricators is preparing to launch “in the near future”.

The sensor readings, user changes and errors will be logged in a database aboard the vessel. The data generated is expected to be compatible with a number of systems and will meet upcoming IMO OT cybersecurity requirements. As a small lubrication specialist, Hans Jensen Lubricators is collaborating with an outside security consultant to ensure that the IoT module will meet the requirements of customers.

Operational results

The new HJ Smartlube 4.0 solution has been installed on two bulk carriers in normal commercial operating conditions. The vessels are both powered by MAN B&W G80 ME-C Mk9.2 engines. The vessels have been operating on both ultra-low sulphur fuel oil (ULSFO), as well as higher sulphur fuels. One of the vessels was fitted with scrubber and operated on HSFO, while the other vessel operated on fuel of up to 1% S.

The initial analysis of the results indicates that CLOC has been lowered by around 45% following the installation, while the iron content and wear rate were both lowered significantly (by over 90% and almost 80%, respectively).  

The piston running condition of the upgraded engines has also been monitored since the beginning of the trial, confirming that the cylinders are in good condition.

Looking ahead

Regulatory pressures to improve environmental efficiency is coinciding with the likelihood that shipowners may operate ships on fuels with low lubricity such as ammonia or methanol in the coming years.

The Motorship notes that more sophisticated engine control systems and the requirements of alternative fuels are increasing the demands placed upon cylinder lubrication systems.

The system offers precise control over cylinder oil distribution via individually controlled injection valves. The ability to specify quantities for each injection, and the elimination of delays between injections are highly attractive features.

Kristensen also identified the elimination of volumetric efficiency considerations, because of the elimination of the pump after the flowmeter, and the precise timing as benefits of the system.

“By eliminating the lubricator, we remove the delay of 30-50 ms from when a signal to inject is given to the actual injection of the oil. As the HJ Smartlube 4.0 valve is opened and closed at the nozzle tip, the delay from the signal to inject to actual injection is about 3.6 ms and this time is not sensitive to temperature and pipe length,” Kristensen added.

The injection can be dependent on both the quantity and timing, ensuring thorough control over cylinder oil placement in the cylinder.

“The HJ Smartlube 4.0 has windows of injection set, to ensure the cylinder oil is not injected where it is not wanted, e.g. the piston crown or skirt when conducting ring pack lubrication.”

If supplementary cylinder oil injection is required, it can be carried out in the same timing window in the following revolution or injected in other timing windows, where there is more time to facilitate the injection, e.g. spray injection above the piston (SIP).

Looking further ahead, the HJ Smartlube 4.0 also offered the possibility of injecting cylinder oils with differing BNs in the ring pack lubrication and in the SIP, Kristensen said.

“The system is the most flexible available and we are sure that it is able to match any challenges new alternative fuels may provide,” Kristensen concluded.

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