ISO 14681 pdf download.Diesel engines — Fuel injection pump testing — Calibrating fuel injectors
1 Scope
This International Standard specifies two types of calibrating injectors intended for testing and setting diesel fuel injection pumps on test benches. It applies to a) calibrating injectors for different orifice plates, max. delivery range 400 mm³/stroke; b) calibrating injectors with pintle type nozzle, max. delivery range 200 mm³/stroke. The field of application is similar to the calibrating injectors specified in ISO 7440-1 and to the calibrating nozzle specified in ISO 401 0. Compared to the calibrating injector specified in ISO 7440-1 , the calibrating injectors specified in this International Standard represent an advanced stage of design which is more appropriate to modern high pressure/high performance fuel injection systems. Specification of the type of calibrating fuel injectors to be used, the appropriate single hole orifice plate size or pintle nozzle (as applicable), high pressure pipes, exact limits, etc. is left to the manufacturer of the injection equipment and/or the manufacturer of the engine.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 401 0:— 1 ) , Diesel engines — Calibrating nozzle, delay pintle type. ISO 41 1 3:1 988, Road vehicles — Calibration fluid for diesel injection equipment. ISO 7440-1 :1 991 , Road vehicles — Fuel injection equipment testing — Part 1 : Calibrating nozzle and holder assemblies. ISO 7440-2:1 991 , Road vehicles — Fuel injection equipment testing — Part 2: Orifice plate flow-measurement.
3 Requirements
3.1 Calibrating fuel injectors 3.1.1 With single hole orifice plate The two alternative designs of the calibrating fuel injectors with the single hole orifice plate specified in figure 1 1 are shown in figure 1 . 3.1.2 With delay pintle type nozzle The two alternative designs of the calibrating fuel injectors with the delay pintle type nozzle specified in figure 1 4 are shown in figure 2. 3.2 Components The calibrating fuel injectors consist of the components specified in 3.2.1 to 3.4.2 with their functionally critical dimensions. 3.2.1 Holder body The holder body may include two spill tubes:  one tube for the leakage fuel passing the needle valve assembly in the direction to the spring housing;  another tube (optional) used with vented holder only. The holder body is shown in figure 3. 3.2.2 Spring The spring is shown in figure 5. It is designed for low stress in order to prevent fatigue. 3.2.3 Spring seat The spring seat, which provides the connection of the low situated spring with the needle, is shown in figure 6. 3.2.4 Inlet stud with edge filter The inlet stud with edge filter is shown in figure 7. It may be flow-tested as shown in figure 8. The outlet of the fixture (within dotted lines) shall be ambient pressure.
4 Designation
4.1 General The various alternatives of nozzle, nozzle holder, nozzle retaining nut and nozzle opening pressure result in many possible combinations of component content and adjustment. To facilitate concise specification of any particular form of calibrating fuel injector, a) required by the injection pump test schedule, or b) requiring purchase, either in whole or in part, by the operator, the range of calibrating fuel injectors shall be designated in code form as specified in 4.2 and illustrated in the following example.4.2 Composition 4.2.1 First element: International Standard number The first element is the number of the International Standard which specifies the calibrating fuel injectors. In the example: ISO 1 4681 4.2.2 Second element: letter code In the example: A This single letter code allows extension of the present A code system if and when all the possibilities of the code tables (see 4.2.3.2) are filled by new or modified orifice plates, nozzle types and/or holder bodies; then the letter ‘A’ shall be changed to ‘B’, etc. This presupposes that additional ‘B’ code tables will be established. In the ‘B’ system the meaning of either one of the digits may, however, retain the same meaning as in the ‘A’ code but this shall be duplicated in the ‘B’ code tables.