82388M Mariner NUT

Operating the Engine and the Driven Equipment
Check the gauges and the driven equipment frequently during engine operation under a load. At certain ratings, the engine can be operated for extended periods of time at full load.Partial Load Operation
Extended operation at reduced load (less than 30%) may cause increased oil consumption and carbon buildup in the cylinders. Extended operation at reduced load may also cause fuel to slobber through the exhaust system. This fuel slobber and oil consumption can result in either loss of power, poor performance, or aftertreatment system damage.To maintain engine efficiency and performance, apply a full load each hour or operate the engine at a load that is greater than 30%. These actions will burn excess carbon from the cylinders. Operating the engine at 30% or higher will also keep the aftertreatment system in normal operating condition.Note: Understand the partial load operation capabilities of your engine system and follow the recommendations in this section. By following the recommendations, you can avoid the need to follow the hydrocarbons release procedure or possible engine system damage.SCR Performance and Hydrocarbons (HC)
Diesel engine combustion produces hydrocarbons (HC) in the exhaust gas emissions. Engine HC emissions are part of normal engine operation, and the levels are further reduced with the use of the SCR aftertreatment system. Certain operating conditions (typically, less than 200° C (392° F) SCR Inlet Temperature) such as continuous idle at low engine speeds and/or loads, can cause temporary reduced catalyst performance and, upon immediate return to higher loads, may result in catalyst damage due to rapid increase in exhaust gas temperature.Your power system is equipped with a strategy to protect the aftertreatment by regulating or limiting the available power to avoid such an event. Caterpillar has designed the Marine Engine and Aftertreatment system to operate safely without risk to the catalyst for 12 hours of low idle and/or continuous low load operation.
Table 1
Application Maximum Duration Minimum Sea Water Temp
Propulsion 12 hours at 10% Load 10° C (50° F)
Auxiliary 24 hours at 15 % Load While managing SCR Inlet temperature and applying load, your engine system safely removes accumulated HC while gradually allowing the system to return to full available power.The engine system protection strategy is always active during operation. In an emergency this protection can be overridden using the engine protection override feature. Throughout operation, the engine system may experience the following codes:SPN 2434-1 Engine Exhaust Manifold #1 Temperature #1: Low - Most Severe (3)
When SPN 2434-1 is active, this code requires the operator to follow the HC Release Procedure.Level 3 - The Level 3 code indicates that the vessel operator must follow an HC Release Procedure to remove the high HC accumulated on the catalyst and protect the catalyst from damage while allowing the vessel to return to operation without derate. In an emergency the engine protection override feature can be activated to allow full engine power however catalyst damage could occur.SPN 2434-18 Engine Exhaust Manifold #1 Temperature #1: Low - Moderate Severity (2)
If SPN 2434-18 is active, continued idling or low load operation (typically 20% load or less) may result in reduced power capability.Level 2 - The Level 2 code is annunciated to provide the vessel operator or technician a warning to change operation to prevent high HC accumulation, avoid possible derate in power if the low load condition continues, and reduce the potential of catalyst damage. Engine HC Release Procedure must be ran to avoid Level 3 Alarm and derate that reduces available engine power to 50%.SPN 1237-31 Display indication that the customer has overridden the derate using the engine protection override feature.
Thermal Management/Mitigation
Hydrocarbon (HC) Release Procedure
If your Cat Marine Engine and Aftertreatment System are in a Level 2 or Level 3 code situation, then the vessel operator or engineer will need to find an opportunity to increase engine load to target a higher exhaust temperature. For variable speed propulsion applications, targeting a higher exhaust temperature can be accomplished by temporarily increasing engine speed thus load on the engine. The HC Release Procedure below will allow the engine to raise engine exhaust temperature and remove the accumulated HC from the catalyst system.For the HC Release Procedure, operating schedules are listed below for various C32 Marine Propulsion and Auxiliary applications to remove hydrocarbons sufficiently from the catalyst and return to work.Note: Times of HC Release Procedure may vary due to differing ambient conditions and vessel design.To perform the HC Release Procedure to remove HC from the catalyst effectively and efficiently, follow the guidelines listed in the tables below that are applicable to the engine rating.
Table 2
C32 Propulsion
HC Release
Speed (RPM) SCR Inlet Temperature Time (Min)
1000 200° C (392° F) 2.5
1200 250° C (482° F) 2.5
1300 300° C (572° F) 5
1500 350° C (662° F) 50
Table 3
C32 1500 RPM 50Hz Auxiliary HC Release
Speed (RPM) Power (kW) SCR Inlet Temperature Time
1500 260 300° C (572° F) 20
1500 350 342° C (648° F) 10
1500 610 410° C (770° F) 30
Table 4
C32 1800 RPM 60Hz Auxiliary HC Release
Speed (RPM) Power (kW) SCR Inlet Temperature Time
1800 400 300° C (572° F) 20
1800 596