C8.7 Marine Engine Product Description Caterpillar

Product Description
1.1. Engine Specifications
2.1. Electronic Engine Features
3.2. Common Rail Fuel Injection System
4.2. Engine Diagnostics
5.2. Engine Speed Governing
6.1. Engine Cooling and Lubrication
7.1. Fuel System
8.1. Engine Service Life

C8.7 Marine Engines are electronically controlled diesel engines. The engines have electronic unit injectors. The engines are equipped with seawater aftercooling. Engine efficiency and engine performance depend on adherence to proper operation and maintenance recommendations. Use the recommended fuels, lubrication oils, and coolant. Ensure proper maintenance of the air cleaner, fuel system, lubrication system, and the cooling system. Refer to this Operation and Maintenance Manual for additional information on maintenance items.

Engine Specifications

Table 1
C8.7 Marine Engine Specifications    
Cylinders and Arrangement     In-line 6    
135 mm (5.3 inch)    
117 mm (4.7 inch)    
Compression Ratio     14.4 : 1    
Aspiration     Turbocharged and supercharged    
8.7 L (531.5 cubic inch)    
Firing Order     1-4-2-6-3-5    
Rotation (flywheel end)     Counterclockwise    
Control system     Electronic    
Method of fuel injection     Electronic fuel injectors
Common rail    
Maximum injection pressure    
1600 bar (23200 psi)    
Method of starting     Electronic starting motor    
Method of cooling the turbocharged and supercharged air     Sea water intercooling and aftercooling    

Electronic Engine Features

Cat C8.7 Marine Engines are designed for electronic controls. The integral on board computer controls the operation of the engine. Current operating conditions are monitored. The Electronic Control Module (ECM) controls the response of the engine to these conditions and to the demands of the operator. These conditions and operator demands determine the precise control of fuel injection by the ECM. The electronic engine control system provides the following features:

  • Engine monitoring

  • Engine speed governing

  • Automatic air/fuel ratio control

  • Torque rise shaping

  • Injection timing and quantity control

  • System diagnostics

For more information on electronic engine features, refer to the Operation and Maintenance Manual, "Engine Features and Controls" topic (Operation Section).

Common Rail Fuel Injection System

The common rail fuel injection system performs the following functions:

  • Pressurize the fuel

  • Meter the fuel

  • Time the fuel injection

The fuel pump pressurizes the fuel. The fuel pump pumps the fuel to the fuel rail. The common rail fuel injectors inject fuel into the cylinders at a precise time. The fuel is injected into the cylinders with the appropriate volume. Electronic sensors on the engine determine time and volume of fuel injection.

Engine Diagnostics

The engine has built-in diagnostics in order to ensure that all of the components are functioning properly. In the event of a deviation from the programmed limits, the operator will be alerted to the condition by the following: "DIAGNOSTIC" lamp (OEM installed), MECP1 (optional) and displays (OEM installed). Under certain conditions, the engine horsepower and the vessel speed may be limited. A Cat electronic service tool may be used to display the diagnostic code.

Diagnostic codes are logged and stored in the ECM. For additional information, refer to theTroubleshooting manual.

Engine Speed Governing

The ECM provides electronic governing that controls characteristics of fuel injection in order to maintain the desired engine rpm. The functionality of electronic governor is similar to the Cat mechanical governor, but the electronic governor includes additional features.

Engine Cooling and Lubrication

The cooling system consists of the following components:

  • Gear driven sea water pump

  • Intercooler and aftercooler

  • Engine oil cooler

  • Jacket water temperature regulator

  • Jacket water pump

  • Heat exchanger

  • Coolant expansion tank

  • Fuel cooler

  • Optional engine mounted transmission oil cooler

  • Optional wet (sea water) exhaust riser

The engine lubricating oil that is supplied is cooled by an engine oil cooler. The engine lubricating oil is also filtered. Bypass valves provide unrestricted flow of lubrication oil to the engine components during the following conditions:

  • High oil viscosity

  • Plugged oil cooler or plugged oil filter elements (paper cartridge)

Fuel System

The fuel system consists of the following components:

  • ECM controlled off-engine electric priming pump

  • Off-engine primary fuel filter and water separator

  • Transfer pump

  • Secondary fuel filter

  • High pressure common rail fuel pump

  • Fuel rail

  • Electronically controlled injectors

  • Fuel cooler

  • Water-in-fuel sensor (optional)

The electric priming pump primes the system with fuel after a fuel system service. The electric priming pump also primes the system with fuel if the engine has not run for an extended period.

Engine Service Life

Engine efficiency and maximum utilization of engine performance depend on the adherence to proper operation and maintenance recommendations. In addition, use recommended fuels, coolants, and lubricants. Use the Operation and Maintenance Manual as a guide for required engine maintenance.

Expected engine life is predicted by the average power that is demanded. The average power that is demanded is based on fuel consumption of the engine over a time. Reduced hours of operation at full throttle and/or operating at reduced throttle settings result in a lower average power demand. Reduced hours of operation will increase the length of operating time before an engine overhaul is required. For more information, refer to the Operation and Maintenance Manual, "Overhaul Considerations" topic (Maintenance Section).

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