HOSE 4231984 - Caterpillar

Fuel System Electronic Control Circuit
The injection pump, the fuel lines, and the nozzles that are used in the traditional Caterpillar diesel engines have been replaced with a mechanically actuated electronically controlled unit injector in each cylinder. The engine has two solenoids on each injector that controls the amount of fuel that is delivered by the injector. The ECM sends a signal to each injector solenoid in order to provide complete control of the fuel to the engine.Electronic Controls
The electronic control system provides complete electronic control of all engine functions. The electronic control system consists of the following three types of components: input, control and output. Sensors monitor engine operating conditions. This information is sent to the ECM. The ECM has three main functions. The ECM provides power for the engine electronics and monitors input signals from the engine sensors. The ECM also acts as a governor to control engine rpm. The ECM stores active faults, logged faults, and logged events. The Personality Module is the software in the ECM which contains the specific maps that define power, torque, and rpm of the engine. The ECM sends electrical current to the output components in order to control engine operation.Fuel Injection Timing and Delivery
This engine uses an injection system control that allows variable control of the spray pattern of the injector during the duration of fuel injection into the cylinder. A pilot injection takes place in order to start fuel combustion in the cylinder. When the pilot injection has been completed, the fuel injection delivery is then controlled by the ECM in order to optimize the combustion efficiency for the current operating conditions. The pilot injection requires a new camshaft with a modified injector lobe.The ECM controls the amount of the fuel that is injected by varying the signals to the electronic unit injectors. The electronic unit injectors will inject fuel only if the electronic unit injector solenoid is energized. The ECM sends 120 VDC to the solenoid in order to energize the solenoid. By controlling the timing of the 120 V signal, the ECM can control injection timing. By controlling the duration of the 120 V signal, the ECM can control the injected fuel amount.The ECM sets certain limits on the amount of fuel that can be injected. The Fuel Ratio Control FRC fuel position is a limit that is based on boost pressure in order to control the air/fuel mixture for the emission control. When the ECM senses an increase in the boost pressure, the ECM increases the FRC fuel position. The rated fuel position is a limit that is based on the horsepower rating of the engine. The rated fuel position is similar to the rack stops and the torque spring on a mechanically governed engine. The rated fuel position provides the horsepower and the torque curves for a specific horsepower rating. The limits are programmed by the factory into the personality module.Injection timing depends on three factors: the engine speed, the engine load and other engine