BS ISO 7876-5:2004

Fuel injection equipment. Vocabulary. Common rail fuel injection systems | Status: Superseded, Withdrawn

1 Scope This part of ISO 7876 establishes a vocabulary for common rail (CR) fuel injection systems for diesel (compression-ignition) engines and their components. The terms defined in this part of ISO 7876 are unique to common rail fuel injection systems; terms and definitions relating to other fuel injection systems are to be found in the other parts of ISO 7876.

NOTE When the word “fuel” is used in the terms listed, it can be omitted providing there can be no misunderstanding.

2 Terms and definitions

2.1 common rail [fuel] injection system CR [fuel] injection system high-pressure fuel injection system, characterized by a component, the rail (2.8), which supplies the individual CR injectors (2.5) with highly pressurized fuel and reduces pressure pulsation in the high pressure system Note 1 to entry: It is also characterized by the following features:

• — the rail pressure may be varied independently from engine speed and load and is electronically controlled;
• — the start and the end of the injections are controlled by an electronic valve at the CR injector;
• — the energy for the injections is supplied to the CR injectors via a rail with highly pressurized fuel;
• — the injections occur directly from the rail.

2.2 fuel feed pump low-pressure pump delivering fuel from the tank via one or several filters to the high-pressure-generating components 2.3 high-pressure supply pump mechanically driven pump of any configuration (gear pump, piston pump etc.) which is able to deliver the necessary amount of fuel at the highest required pressure Note 1 to entry: This pump may include a device or devices for regulating the delivered quantity of fuel to the rail (2.8). 2.4 internal transfer pump pre-supply pump (e.g. vane type pump, gear pump) integrated in the housing of the high-pressure supply pump (2.3) and driven by the same shaft 2.5 CR [fuel] injector fuel injector that includes the features of a conventional fuel injector and, additionally, a device for controlling the start and end of the injection, e.g. by means of a solenoid-operated or piezo-driven valve Note 1 to entry: The CR injector may or may not contain a pressure amplifier for the injection pressure; the amplifier is actuated by highly pressurized fuel. Note 2 to entry: For the definition of conventional fuel injector, see ISO 7876-2. 2.6 pressure control valve electrically actuated spill valve in the high-pressure system designed to control and vary the pressure in the rail (2.8) to the required values depending on speed and load of the engine 2.7 volumetric control valve valve that controls the fuel supply of the high-pressure supply pump (2.3) according to the demand 2.8 rail high-pressure storage chamber with the twin functions of supplying the CR injectors (2.5) with fuel and reducing pressure pulsation in the high-pressure system caused by the individual injections Note 1 to entry: It may be manufactured as a separate part (e.g. a tubular device) attached to the engine or may be a channel within the cylinder head. 2.9 flow limiter device located between the rail (2.8) and each CR injector (2.5) designed to shut off the fuel flow in the pipe if the maximum permitted flow is exceeded 2.10 flow damper device located between the rail (2.8) and each CR injector (2.5) designed to moderate the fuel pressure pulsation in the pipe caused by each injection Note 1 to entry: This damper may also act as a flow limiter (2.9). 2.11 [CR] pressure sensor sensor designed to measure the pressure within the rail (2.8), providing an electrical signal to the electronic control unit (2.13) 2.12 pressure limiter safety valve designed to limit the operating pressure to the maximum permitted pressure 2.13 electronic control unit device that actuates the CR injectors (2.5) and other valves, e.g. the volumetric control valve (2.7) or pressure control valve (2.6), depending on the speed and load of the engine and on other operating conditions (air temperature, coolant temperature, boost pressure, etc.) 2.14 inlet throttling device inlet flow control valve device designed to throttle the fuel flow at the inlet of the high-pressure supply pump (2.3) in order to control the quantity of the highly pressurized fuel delivered to the rail (2.8)