3512B Marine Auxiliary Engine Caterpillar

The engine is an electronically controlled, mechanically actuated unit injector diesel engine. The engine is a 60 degree V-12 arrangement. The engine has a bore of 170 mm (6.7 inch) and a stroke of 190 mm (7.5 inch). The displacement for the V-12 is 51.8 L (3158 cu in). The engine is configured for an aftercooling system that is cooled by the jacket water. The engine utilizes a two-piece piston with a forged steel crown and a cast aluminum skirt.

The electronic unit injector (EUI) eliminates many of the mechanical components of a mechanical unit injector. The EUI also provides increased control of timing. The timing advance is achieved by the precise control of the injector firing time. Engine rpm is controlled by adjusting the firing duration. A special pulse wheel provides information to the electronic control module for detection of the cylinder position and the engine rpm.

The engine has built-in diagnostics in order to ensure that all of the components are operating properly. An electronic service tool can be used to read diagnostics. Refer to the Troubleshooting Manual for the proper procedures on the use of the electronic service tool.