Case Farmall 40B CVT, 45B CVT, 50B CVT Tractor Repair Manual

Manuals: Service Manual
Introduction
Engine
Clutch
Transmission
Four Wheel Drive System
Front Axle
Rear Axle
Power Take Off
Brake and Controls
Hydraulic Systems
Steering
Cab Climate Control
Electrical System
Platform, cab, bodywork and decals
Special Tools
Electrical Schematic
Manual Extract: Fuel injectors – Dynamic description
Throttle-type injectors are used in all engine applications.

The injectors have a 1.0 mm (0.04 in) single orifice and are set at 14824 kPa (2150 psi). The pressure adjustment is made by adding or deleting shims from the top of the injector pressure adjusting spring. The injectors have an injection angle of 4 °. The injector pipes are of the same length for each cylinder to help keep the injection intervals in time.

The engine injection function is to inject fuel into a pressurized cylinder in a fully atomized condition, which provides efficient combustion with minimum amount of smoke. Each injector assembly consists of a nozzle assembly containing a needle valve, a nozzle holder assembly, and injector needle valve regulating spring.

Fuel from the injection pump enters the injector inlet and passes down through a drilling in the nozzle holder and body to the needle valve seat. The fuel pressurized by the injection pump, lifts the needle valve off the seat against the action of the spring pressure. The fuel is then forced, in the atomized state, through the 1.0 mm (0.04 in) orifice in the nozzle tip. When pressure from the injection pump drops, the needle valve snaps back onto its seat under pressure from the spring.

To provide lubrication of the injector, a small amount of fuel is permitted to leak up between the needle valve and the nozzle body. The excess fuel rises to the top of the injector and returns to the fuel tank through the injection leak-offline.