In marine applications, it can be easy to overlook four-stroke when so many vessels use two-stroke for their main source of propulsion. Two-stroke is the more popular choice overall and is particularly beneficial when it comes to fuel selection for example. Most modern large merchant vessels use slow speed two-stroke engines and engine size requirement usually dictates this format.
Most large vessels, however, will have a series of four-stroke auxiliary engines. In addition, smaller and medium-sized vessels such as ro-ro ferries, will tend to use four-stroke as their main propulsion engines due to their lower power requirement and relative compactness of engine size.
In summary, both engine types have their advantages and disadvantages depending on vessel size, layout and power requirements, and each type requires its own condition monitoring.
Simplex-Turbulo is a distributor for Parker Condition Monitoring and its compact Online Fluid Condition Sensor (FCS) is proving popular with operators of four-stroke engines, where space restrictions benefit such a device.
The FCS may be small, but it is a highly robust, online multi-parameter sensor designed to prevent damage associated with low quality, incorrect fuel or oil lubrication. It provides constant, real-time monitoring of any four critical parameters, including oil quality (permittivity or conductivity), moisture content, temperature and pressure.
The FCS suits four-stroke engines well because they use lubrication oil taken from a sump/tank. The oil is re-used until its changed, so it is constantly run through the engine. Fixing a sensor to the engine loop to monitor the oil, saves an engineer having to collect regular samples, that are then sent off for laboratory analysis at considerable time and expense.
Bunker suppliers dictate that shipowners and charter parties must act quickly to make a claim if they have identified that their fuel is out-of-spec, so having the ability to immediately determine this onboard a vessel is invaluable. It is worth remembering that laboratories are often working at full capacity, so obtaining critical and time-sensitive results can be met with delays.
Prevention is always better than cure, and the compact size of the FCS that provides real-time data onboard a vessel, is a useful tool in any condition monitoring regime.