20460424 Volvo.Penta Alternator

Electronic Controls
The engine's electronic system consists of the Engine Control Module (ECM), the engine sensors, the injection actuation pressure control valve, and the vehicle interface. The ECM is the computer. The personality module is the software for the computer. The personality module contains the operating maps. The operating maps define the following characteristics of the engine:
Horsepower
Torque curves
Engine speed (rpm)Engine Governor
The electronic controls on the engine serves as the engine governor. The electronic control system determines:
The timing of the fuel delivery to the cylinders
The amount of fuel that is delivered to the cylinders
Injection pressureThe electronic control system uses the actual conditions and the desired conditions in order to make the decisions. The electronic control system controls the engine during starting and operation.
Illustration 1 g00693055
The governor considers the desired conditions and the actual conditions. The governor then takes the action that best accommodates the desired conditions. The desired conditions are typically the accelerator pedal position, the desired vehicle speed during cruise control, or the desired engine speed during PTO control. The actual conditions are based on current operating conditions such as coolant temperature, load conditions, etc.Timing Considerations
Once the ECM has determined the amount of fuel that is required, the ECM must then determine when the injection is needed. Injection timing is determined by the ECM after considering input from the coolant temperature sensor, the sensor for the intake air temperature, and the boost pressure sensor.
Illustration 2 g00693339
The ECM knows the cylinder position for timing because of the signal from the engine speed/timing sensors. The ECM adjusts timing for best engine performance, for fuel economy, and for the control of white smoke. Actual timing and desired timing cannot be viewed with the electronic service tool. The ECM determines the location of top center of the number one cylinder from the signal that is provided by the engine speed/timing sensors. The ECM decides when injection should occur relative to top center. The ECM then provides the signal to the injector at the desired time.Fuel Injection
The ECM controls the amount of fuel that is injected by varying the signals to the injectors. The injectors will pump fuel only if the injector solenoid is energized. The ECM sends a high voltage signal in order to energize the solenoid. The injector solenoid unseats the poppet valve. The oil path to the drain passage will close while the inlet oil passage opens for