881326 2 Mercury SCREW, Drain

Illustration 1 g06079936The fuel flows from the main gas supply through a knock-down regulator. A knock-down regulator is a second regulator that is needed when the gas supply pressure is too high for a single regulator to manage.From knock-down regulator, the fuel flows to the fuel filter. Usually, the fuel filter is a component of the design at the particular site. The customer is responsible for supplying clean, dry fuel to the engine. The fuel filter may be supplied by Caterpillar or by the customer. To prevent particles from entering the engine, a 1 micron filter is recommended. Select a filter that is properly sized for the required gas pressure.For installation of the fuel filter, the recommended location is close to the engine before the gas pressure regulator. Pressure gauges in the gas lines on each side of the fuel filter are recommended to monitor the differential pressure. A manual shutoff valve in the gas line before the fuel filter will facilitate servicing of the filter.The filtered fuel flows to the gas pressure regulator.The regulator is supplied by Caterpillar.A regulated pressure of 3.5 kPa to 35 kPa (.5 psi to 5 psi) is required to ensure acceptable operation.Steady state fuel pressure stability requirement of 6.9 mbar/sec (1 psi/sec). Transient fuel pressure stability requirement of 48.2 mbar/sec (7 psi/sec).Less gas pressure may result in reduced power. More gas pressure may result in instability.The fuel flows from the gas pressure regulator to the Gas Shutoff Valve (GSOV).The GSOV may be supplied by Caterpillar or by the customer. The solenoid for the GSOV may be connected to engine wiring harness or to a harness that is supplied by the customer. In either case, the customer may install a switch that can interrupt the circuit.The control system is configured for a GSOV that is energize-to-run. This statement means that the GSOV must be energized in order for the engine to run. The GSOV may be energized by customer supplied equipment or by the ECM. When the GSOV is energized, the valve opens and the fuel flows to the engine. When the control system shuts down the engine, the voltage is removed from the solenoid. The valve closes and the fuel is shut off.The fuel flows to the electronically controlled fuel metering valve . The ECM issues a command signal to the fuel metering valve via the CAN data link. The fuel metering valve regulates the flow of fuel to the engine.The fuel metering valve controls the volume of fuel that flows to adapter for the air inlet elbow. The inlet air that is necessary for combustion also enters the adapter. The air/fuel mixture enters turbocharger compressor.The compressed air/fuel mixture flows through the aftercooler and then to the electronically controlled throttle.The temperature of the compressed air/fuel mixture is reduced in the aftercooler resulting in an increased density of the air/fuel mixture. This action results in more efficient combustion.The ECM issues a command signal to the actuator for the throttle via the CAN data link. The signal is based on the desired engine speed. The throttle controls the volume of the air/fuel mixture that flows through the throttle to the air inlet manifold.The manifold distributes the air/fuel mixture through the spark arrestor to the cylinders for combustion.