0335141 JOHNSON COUPLING,DRIVE

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: Do not idle the engine for longer than 12 hours without loading the engine and maintaining a 30% or higher load on engine.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. Also, 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 designed the 3516 Offshore Petroleum Engine and Aftertreatment system to operate safely without risk to the catalyst for 20 hours of continuous low load operation at 1200 RPM.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 rig 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 rig 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 percent load or less) may result in reduced power capability.Level 2 - The Level 2 code is annunciated to provide the rig operator or technician a warning to change operation to prevent high HC accumulation. Changing operation will also 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 Engine and Aftertreatment System are in a Level 2 or Level 3 code situation, the rig operator or technician will need to increase engine load to target a higher exhaust temperature. The HC Release Procedure 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 for two IMAT conditions for the Offshore Petroleum applications to remove hydrocarbon sufficiently from the catalyst and return to work.Note: Times of HC Release Procedure may vary due to differing IMAT or ambient conditions and rig design.To perform the HC Release Procedure to remove HC from the catalyst effectively and efficiently, follow the guidelines listed in the table below that is applicable to the engine rating.
Table 1
3516 Offshore Petroleum Engine
Load (%) 25° C (77° F) IMAT 55° C (131° F) IMAT
10 10 hours 210° C (410° F) 1.75 hours 230° C (446° F)
25 1 hour 270° C (518° F) 19 minutes 310° C (590° F)
50(1) 21 hours 305° C (581° F) 6 minutes 365° C (689° F)
(1) Load to 25% for 15 minutes, then proceed to target SCR temperature inlet temperature listed.The procedure duration will vary based on the ambient conditions, HC loading percentage, and the available engine load (%). For the operator to perform the procedure, engine speed, engine load (%), or power (kW) and SCR inlet temperature are to be displayed.Preferred Load Step
25% Engine Load for all IMAT to remove HC
Perform the following procedure:
Before increasing speed or load, ensure that all requested parameters are visible.
For the 3516 Offshore Petroleum engine, prepare the rig so that the engine can safely be loaded for the desired engine loading for the prescribed time. For example: at 25° C (77° F), prepare the rig to load the engine at 25% engine load for more than 1 hour.
Find the appropriate HC Release Procedure for your Offshore Petroleum Engine System. When ready raise the engine speed to 1200 RPM with no engine load. Then gradually apply the engine load up to the desired engine load while monitoring the SCR Inlet Temperature. Use the engine speed or load references for this step to maintain the SCR Inlet Temperature listed in the procedure continuously for the time prescribed. For example: at 25° C (77° F), target an SCR inlet temperature of 270° C (518° F).Note: The SCR Inlet Temperature may go over the targeted SCR Inlet Temperature. Adjust the engine load to keep the SCR Inlet Temperature no greater than 15° C (59° F) over the SCR Inlet Temperature target