PLUG 6B5262 - Caterpillar

Note: The information in this manual refers to gas engines with low-pressure fuel systems.The CG137 Engines are standard engines with low-pressure gas fuel systems. These engines are used for industrial applications and generator set applications. The engines will successfully operate on commercial pipeline natural gas and wellhead gas (field gas).Fuel System
For the low-pressure gas fuel system, the carburetor is located after the air cleaner. Filtered air and gas are mixed in the carburetor. The mixture is compressed by the turbocharger (if equipped). The fuel system operates with a gas pressure between 10 to 34.5 kPa (1.5 to 5 psi). The fluctuation of the fuel supply pressure should not exceed 1.7 kPa ( 0.25 psi) in order to maintain stable operation. This pressure meets the ISO8528 Class 1 standards for transient response.Ignition System
The engine is equipped with electronic ignition which is controlled by the electronic control module (ECM) and with conventional spark plugs. The system provides dependable firing and low maintenance. The system provides precise control of the duration of the spark and the ignition timing.The system also provides diagnostic capability that enhances troubleshooting. Primarily, the ignition wiring is routed externally. A short stretch of wire is routed under the valve covers.Lubrication System
The engine lubrication oil is circulated by a gear-driven pump. The oil is cooled and filtered. A bypass valve provides unrestricted flow of lubrication oil to the engine parts if the engine oil filter elements become plugged.Cooling System
The standard cooling system has a gear-driven pump. The cooling system has two temperature regulators that regulate the outlet temperature of the coolant. The temperature depends on the application. Jacket water coolant temperature is limited from 93 to 99 °C (200 to 210 °F).For engines with a Separate Circuit Aftercooler (SCAC), the air is cooled by a heat exchanger. The water that cools the air in the heat exchanger is in a circuit that is separate from the jacket water. The aftercooler coolant is pumped by an auxiliary water pump. The SCAC is required to operate at one of the following temperatures. The engine rating depends on the temperature and the application.
54 °C (130 °F)Specifications
Table 1
CG137 Engine Specifications
Item CG137-12 Engine
Rated speed (rpm) 1800
Cylinders and arrangement 65 degree V-12
Bore 137 mm (5.4 inch)
Stroke 152 mm (6 inch)
Compression Ratio 8.5:1
Aspiration Turbocharged Aftercooled (TA) (1)
Total displacement 27 L (1648 in3)
Firing order 1-4-9-8-5-2-11-10-3-6-7-12
Rotation (flywheel end) Counterclockwise
(1) Separate Circuit Aftercooling (SCAC)
Illustration 1 g02728065
CG137-12 Engine design
(A) Inlet valves
(B) Exhaust valves
(C) Flywheel Engine Service Life
Engine efficiency and maximum utilization of engine performance depend on adherence to proper operation and maintenance recommendations. These recommendations include the use of recommended lubricants, fuels, and coolants.For the engine maintenance that is required, Refer to the Operation and Maintenance Manual, "Maintenance Interval Schedule".