Exam Question

### (a) Main Engine Ancillary Equipment for Automatic Fuel Viscosity Regulation
**1. Introduction**
The automatic viscosity control system, commonly known as a Viscotherm, is a critical ancillary unit in the heavy fuel oil (HFO) supply line. Its primary function is to maintain the fuel oil viscosity at a precise setpoint (typically 12-15 cSt) just before injection into the main engine. This ensures optimal atomization, efficient combustion, and prevents damage to fuel injection equipment. The system operates as a closed-loop feedback control system.
**2. Key Components**