C-FRAME AS 2519831 - Caterpillar

Start/Stop Control
The ECM contains the logic and the outputs for control of engine prelubrication, of starting, of shutdown, and of the postlube. The customer programmable logic responds to signals from the following components: engine control switch, emergency stop switch, remote start switch, data link and other inputs.To control the engine at the appropriate times, the ECM provides +Battery voltage to the solenoids that control the prelube pump, the starting motor, and the gas shutoff valve.When the programmable logic determines that the prelubrication function is necessary, the ECM supplies +Battery voltage to the solenoid for the prelube pump. The prelubrication must develop sufficient engine oil pressure before the engine will crank. The engine has a pressure switch for the prelube. When the engine oil pressure is sufficient, the pressure switch closes and the engine can be cranked.When the programmable logic determines that it is necessary to crank the engine, the ECM supplies +Battery voltage to the solenoid for the starting motor. Rotation of the crankshaft also operates the pump for the electrohydraulic actuators. The pump develops hydraulic oil pressure for operation of the fuel actuator, the air choke actuator, and the wastegate actuator.The engine has an energize-to-run type of Gas Shutoff Valve (GSOV). When the programmable logic determines that fuel is required to start the engine or to run the engine, the ECM supplies +Battery voltage to the valve's solenoid.At one second after the GSOV is energized, the pressure differential between the fuel and the air is monitored. This parameter is monitored in order to ensure that no fuel is entering the fuel manifold before the ECM issues a command to the fuel actuator. If the differential pressure for fuel to air is less than 0.5 kPa (0.073 psi), the ECM supplies +Battery voltage to the fuel actuator's solenoid.The ECM controls the fuel actuator by adjusting the current flow through the actuator's solenoid. During start-up, the combustion chambers are usually filled with excessive combustion air. The ECM operates the fuel actuator in order to supply sufficient fuel for a combustible air/fuel mixture.The ECM removes the voltage from the starting motor's solenoid when the programmable crank terminate speed is reached or when a programmable cycle crank time has expired. The pinion of the starter motor disengages from the flywheel ring gear.When the programmable logic determines that an engine shutdown is necessary, the ECM removes +Battery voltage from the solenoids for the fuel actuator and for the GSOV. The fuel is shut off.The prelube system is programmed to perform a postlube cycle during engine shutdown. This supplies the turbocharger with adequate lubrication during shutdown.Monitoring Engine Operation
The ECM monitors both the engine operation and the electronic system.Problems with engine operation cause the ECM to generate an event code. The ECM can issue a warning or a shutdown for events. This depends on the severity of the condition.For example, a high pressure pump provides hydraulic pressure with oil for the electrohydraulic system. The oil supply is separate from the engine oil. The high