Engine System Overview 2.3.2 Software Flash File If the ECU is correlated to a computer, then the personality module (also known as “flash file”) is the software for the computer. The term flash file is derived by the method in which the software is programmed into the ECU — a technology known as flash programming. The flash file contains the operating maps that define the performance and operating characteristics of the engine as well as the Industrial application feature support. Once flashed, the ECU contains the following information to identify the flash file and supported ratings:
• Personality Module PN • Software Gp Release Date • Rated Power • Rated Peak Torque • Top Engine Speed Range • Test Spec The information above can be viewed in the Configuration Parameter screen within the Cat ® ET service tool. 2.3.3 Fuel Injector 2.3.3.1 HEUI™ Injector (C7 ACERT and C9 ACERT) The Hydraulically actuated Electronically controlled Unit Injector fuel system is actuated hydraulically by high pressure engine oil. The HEUI injector contains a solenoid to electrically control the quantity, pressure, and timing of the fuel that is injected. Both positive and negative wires to each solenoid are wired directly back to the ECU.
Higher voltages (approximately 70 V) and sharp pulses of relatively high current are used to control the injectors. Injector cables are twisted pairs to minimize emissions of electromagnetic noise. There is no OEM connection to the injectors; however, the OEM should ensure that any systems that are sensitive to electromagnetic radiation are not in proximity to the harness that leads to the injectors. 2.3.3.2 MEUI Injector (C11 ACERT-C32 ACERT) The Mechanical Electronic Unit Injector (MEUI) fuel system is actuated mechanically by the injector lobe on the camshaft. The electronic control and mechanical actuation provide a level of control of the timing and fuel volume.
The timing advance is achieved by precise control of the unit injector timing. Both positive and negative wires to each solenoid are wired directly back to the ECU. Higher voltages (approximately 108 V) and sharp pulses of relatively high current are used to control the injectors. There is no OEM connection to the injectors; however, the OEM should ensure that any systems that are sensitive to electromagnetic radiation are not in proximity to the harness that leads to the injectors. 2.3.4 High Efficiency Pump (C7 ACERT and C9 ACERT, HEUI Only) The unit injector hydraulic pump is a variable delivery piston pump.
The unit injector hydraulic pump supplies a portion of the engine lubrication oil to the HEUI injectors. The high efficiency of the pump combined with the resistance to flow at the unit injectors pressurizes the oil delivered by the pump. 2.3.5 Injection Actuation Pressure Sensor (C7 ACERT and C9 ACERT, HEUI Only) The IAP sensor is installed in the high pressure oil manifold. The high pressure oil manifold supplies actuation oil in order to power the unit injectors. The IAP sensor monitors injection actuation pressure. A P P L I C A T I O N A N D I N S T A L L A T I O N G U I D E 9