Keeping lubricant development in line with engine design changes is key

Over the past couple of years, the maritime industry has witnessed numerous new engine designs receiving design approvals from classification societies, including those running on LNG, methanol, and most recently ammonia.

However, for the switch from high sulphur fuel oil (HSFO) to fuels of the future to run smoothly, ships’ engines have to run smoothly as well.

Hence, efficient cylinder lubrication is critical to having a well-oiled machine.

Steve Walker, Global Marine Equipment Builder Manager at ExxonMobil, believes that for any new engine design, it would be critical that the lubricant is considered as a design component.

“If this is not done it may mean that existing lubricant performance capabilities, with regard to film strength, thermal resistance and ability to keep engine components free of deposits, could be breached,” Walker told Offshore Energy – Green Marine in an interview.

“I have seen this many times in the past when an original equipment manufacturer (OEM) believes there is something wrong with a well-established cylinder oil because, after performing well for years, suddenly it does not achieve good results anymore. In this example, the oil did not change but the machine design parameters did.

“Development and validation of new, higher-performing oils can take over two years, so keeping lubricant development in step with engine design changes is key. This is why ExxonMobil works heavily with OEMs to understand their lubricant needs for future engine designs.

“We have worked extensively with both WinGD and MAN ES to ensure that our oils meet their new and future engine requirements. Once an OEM incorporates oil performance in the design process, significant performance improvements can be made. “

ExxonMobil is using MobilServ℠ Cylinder Condition Monitoring (CCM) which is key to monitor and manage engine performance.

“We are currently working closely with WinGD to link its WiDE data to MobilServ CCM to provide owners and operators with a full picture of their engine’s performance to optimize and ensure most efficient cost to operate,” he said.

Walker foresees that all engine types as they evolve to meet tighter greenhouse gas targets will present fresh performance challenges for lubricants.

“We know this from our extensive experience of dealing with passenger and commercial vehicle sectors that have been handling similar challenges for the past 20 years,” he explained.

Touching upon the design features that would be the most important for the development of the engines of the future and what will that mean for cylinder lubricants, Walker said that cutting fuel consumption and greenhouse gas emissions would be crucial.

“This will likely involve further step changes in engine pressures and corresponding increases in thermal demands in the combustion chamber,” he pointed out.

“In the longer term, we may see material changes to cope with the higher stresses that increased combustion pressures will bring. Ancillary equipment efficiencies are also likely to be considered such as dedicated engine hydraulic circuits allowing the use of efficient hydraulic oils rather than system oil.”

When asked where does he see the most room for improvement of lubrication oils when it comes to bolstering engine performance, Walker said:

“With regards to new lubricant development, the area that needs most work for new engine designs is thermal deposit control. Engines have evolved significantly in the past 15 years yet we see some suppliers still selling 40 BN oils that were developed in the early 2000s.”

Having in mind that the path toward decarbonization of the shipping industry will be driven by multiple fuel choices and not a single fuel, this is also likely to result in oils that are compatible with multiple fuel types.

The key to developing oils that are compatible with multiple fuel types, which would be the ultimate solution for the engines of the future, would be a balanced formulation that works to ensure the key areas of thermal and deposit control are considered for all fuel types, he explained.

“Traditionally for gas engine oil, the aim was low ash but this can limit the amount of additive that can be in the oil to allow thermal, anti-oxidants and deposit combating dispersants,” he stressed.

At the end of May, ExxonMobil launched the Mobilgard 540 X, which is specifically formulated for use with both 0.10% and 0.50% sulphur fuels and liquefied natural gas (LNG). The oil is designed to meet the advanced cleanliness and protection needs of newer engine designs and meets WinGD’s requirements for all three fuel types.

“As the first cylinder oil to be approved for use with all three low-sulphur fuel types and gas validated by WinGD, Mobilgard 540 X is a first-to-market offering in our industry that allows vessel operators to seamlessly switch between these fuels without compromising on quality or performance,” said Frans Horjus, global marine lubricants sales manager at ExxonMobil.

“This should give vessel operators peace of mind that we are constantly looking ahead at future regulatory changes and providing the lubrication solutions to help them navigate the road ahead.”

The transition of the shipping industry to IMO 2020 compliant fuels has been relatively smooth. Offshore Energy – Green Marine wanted to know what was the experience of ExxonMobil, with regard to the feedback from owners when switching to new fuels and optimizing their engines’ performance as well as the potential incompatibility issues.

“I feel that many owners prepared well and trialed the new fuels and lubes early to gain experience. As with anything new, there are cases where issues arise. We have seen in less than one per cent of cases issues that can largely be categorised in the following areas:

o Fuels not segregated adequately

o Large fuel spec variation not being comprehended and therefore fuel treatment not being managed and adjusted effectively

o Combustion quality variations not being noted

o Adjustments to lube feed rate not being checked with under piston inspection to validate correct lubrication.”

Finally, commenting on the potential impact of the pandemic on decarbonization efforts of the shipping industry, Walker said that these are not likely to be impacted as IMO’s goals are long term, coming into force in 2050.

“ExxonMobil is committed to continuing to deliver fuels, lubricants, and services that meet operators’ needs – now and in the future,” he concluded.