C15 and C18 Tier 4 Final Engines General Information Caterpillar

Illustration 1	g01943685
Left side view (1) Secondary fuel filter base (2) Primary fuel filter base (3) Inlet manifold (4) Open crankcase ventilation system (5) NRS control valve (6) NRS venturi (7) Electronic Control Module (ECM) (8) Flywheel housing (9) Oil Pan (10) Fuel transfer pump (11) Vibration damper

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Right side view (12) Exhaust manifold (13) Turbocharger (14) Temperature regulator housing (15) Water pump (16) Oil filter (17) NRS cooler (18) Balance valve actuator

The C15 is an in-line six cylinder engine. The C15 has a bore of 137.2 mm (5.40 inch) and a stroke of 171.5 mm (6.75 inch). The displacement of the engine is 15.2 L (927.56 cu in). Each cylinder has two inlet valves and two exhaust valves. The firing sequence of the engine is 1-5-3-6-2-4.

The C18 is an in-line six cylinder engine. The C18 has a bore of 145 mm (5.7 inch) and a stroke of 183 mm (7.2 inch). The displacement of the engine is 18.1 L (1102.36 cubic inch). Each cylinder has two inlet valves and two exhaust valves. The firing sequence of the engine is 1-5-3-6-2-4.

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Right side view of a C18 with two turbochargers in a series (1) Low-pressure turbocharger (2) High-pressure turbocharger (3) Precooler

Some applications of the C18 will have two turbochargers. The C18 arranges the two turbochargers in series. The two turbochargers allow the engine to have boost over the entire engine rpm range. The use of two turbochargers increases the maximum boost pressure to 410 kPa (60 psi). The engine also uses an air-to-air aftercooler (ATAAC).

The Electronic Unit Injector system (EUI) eliminates many of the mechanical components that are traditionally used in the fuel injector assembly. The EUI also provides increased control of the timing and increased control of the fuel air mixture. The timing advance is achieved by precise control of the fuel injection timing. Engine speed is controlled by adjusting the injection duration.

The ECM monitors the system. The ECM detects problems with the system. In the event of a system component failure, the operator is alerted to the condition by a red stop lamp. The check engine light is located on the dashboard. An electronic service tool can be used to read the numerical code of the faulty component or condition.

Starting the Engine

The Electronic Control Module (ECM) will automatically provide the correct amount of fuel that is necessary to start the engine. The throttle should not be held while the engine is being cranked. If the engine fails to start in 30 seconds, the starter switch should be released. The starting motor should be allowed to cool for 2 minutes before being used again.

Cold Mode Operation

Starting the engine and operation in cold weather is dependent on the type of fuel used, the oil viscosity, and other optional starting aids. For more information, refer to the Operation and Maintenance Manual, "Cold Weather Operation".

The Cold Mode flag in AVSpare Electronic Technician (ET) indicates that the engine system is compensating with a cold mode strategy.

Some examples of a cold mode strategy may include:

• Elevated RPM

• Timing enhancements

• Fuel injection enhancements

Troubleshooting performance-related problems when the Cold Mode flag is active is not recommended.

The Cold Mode flag will activate in the following conditions:

• Coolant temperature is less than 35° C (95° F)

• Coolant temperature is less than 75° C (167° F) and NRS gas temperature is less than 35° C (95° F)

• Coolant temperature is less than 75° C (167° F) and NRS gas temperature is less than 65° C (149° F)

Once coolant temperature is above 75° C (167° F) and NRS gas temperature is greater than 65° C (149° F) for 10 minutes, no cold mode strategy will be active.

Delayed Engine Shutdown (If Equipped)

The "Delayed Engine Shutdown" strategy allows the engine to run for a time after the engine start switch key is turned to the OFF position to cool the engine and system components. The engine start switch key may be removed.

Note: There may be regulations that define the requirements for the operator and/or support personnel to be present when the engine is running.

Note: The DEF purge process will run for 2 minutes once the engine is shutdown and must complete. The purge process may occur during "Delayed Engine Shutdown". It is important not to turn the battery disconnect switch OFF during the purge process. Do not turn the battery power disconnect switch OFF until battery disconnect switch indicator lamp has turned OFF. If the purge process does not complete, a diagnostic code will become active.

Show/hide table

Leaving the machine unattended when the engine is running may result in personal injury or death. Before leaving the machine operator station, neutralize the travel controls, lower the work tools to the ground and deactivate all work tools, and place the lever for the hydraulic lockout control in the LOCKED position.

Note: Leaving the engine unattended while running may result in property damage in the event of a malfunction.

Delayed Engine Shutdown Lamp

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The Delayed Engine Shutdown strategy will run whenever the DPF outlet temperature is above a threshold at engine shutdown. The temperature needs to drop below that threshold before Delayed Engine Shutdown will end. There is a parameter in Cat ET, "Delayed Engine Shutdown Aftertreatment Outlet Gas Temperature Threshold" which can be configured between 200° C (392° F) and 575° C (1067° F). The default setting is engine iron set or application specific and originally set by the product group. Only an authorized dealer using passwords through AVSpare's Feature Protection System (FPS) can change the threshold. When the estimated DPF outlet temperature drops below the programmed value, the DES will end and the engine will shutdown. There is also a "Delayed Engine Shutdown Maximum Time" parameter in Cat ET. This will shutdown DES once the threshold time is met regardless if it has dropped below the temperature threshold. The minimum time it can be set to is 7 minutes (default) for machine engine customers and 4 minutes for commercial engine customers. The maximum time it can be set to is 30 minutes. Once programmed in the factory the time can only be increased with FPS by an authorized dealer. (i.e. if it comes programmed at 20 minutes, a dealer can only increase it up to 30, can not lower it below 20). Once Delayed Engine Shutdown begins, it will always run for a minimum of 76 seconds even if temperature drops below threshold before that.

When the engine start switch key is turned to the OFF position and delayed engine shutdown is active, the "Delayed Engine Shutdown" lamp will illuminate and/or the following text will be displayed on the dash: Engine Cooldown Active.

Note: There is either a STOP (1) orDELAYED ENGINE SHUTDOWN (1A) position on the key switch. To override delayed engine shutdown and stop the engine, turn the engine start switch key to the STOP (1) or DELAYED ENGINE SHUTDOWN (1A) position. Overriding the delayed engine shutdown may reduce engine and system component life. A warning message and/or audible alarm will be initiated and a fault code will be logged for improper engine shutdown.

Illustration 5	g03740759

Illustration 6	g03740766

Note: At any time during a delayed engine shutdown, the engine start switch key may be turned to the ON position. The engine may be placed back into service.