TL960 SERVICE MANUAL
Electronic controls such as these are invaluable in meeting new standards of exhaust emissions and noise while maintaining excellent fuel economy. The ECM has the ability to store data on mileage, fuel consumed, and hours operated.
High Pressure Oil Supply Pump: The hydraulic supply pump is a seven-piston fixed displacement axial piston pump. It raises the system's oil pressure level from typical engine operating oil pressure of 40 psi to the actuation pressure required by the injectors of 870 to 3300 psi. During normal engine operation, pump output pressure is controlled by the Injector Actuation Pressure Control Valve (IAPCV) which dumps excess flow back to the return circuit. Pressures for specific engine conditions are determined by the ECM.
Injector Actuation Pressure Control Valve: The IAPCV is an electrically operated dump valve which closely controls pump output pressure by dumping excess flow back to the oil sump. A variable signal from the ECM to the IAPCV determines pump output pressure. Pressure while cranking a cold engine (below 500F [100C]) is slightly higher because cold oil is thicker and components in the injector move slower. The higher pressure and advanced injection timing helps the injector to fire faster until the viscosity of the oil is reduced.
HEUI Injector: The injector uses the hydraulic energy of the pressurized oil to cause injection. The pressure of the incoming oil controls the speed of the intensifier piston and plunger movement, and therefore, the rate of injection. The amount of fuel injected is determined by the duration of