Diesel injector test bench

Abstract

The utility model relates to engine building, in particular to test rigs for diesel injectors, and can be used at diesel engine manufacturing plants, service centers, and maintenance stations. The injector testing rig includes a mounting stand (2) with clamps (5, 6) for securing the injector (3) under test, an injection chamber (10), a fuel feed pump (20), a high-pressure fuel pump (21) with a hydraulic accumulator (25), and an automatic control system. A sector receiver (11) with sector reflectors (12) on which photoelectric sensors (14) are placed is mounted coaxially inside the injection chamber (10). The novelty of the rig lies in the fact that the photoelectric sensors (14) are equipped with linear stepper motors (31) with built-in lead screws, ensuring their movement relative to the injector along the atomization axis.This design allows for recording parameters in various spatial cross-sections, ensuring a more accurate determination of the dynamic and geometric characteristics of the fuel spray. Fuel spray velocity is determined by recording the moment of signal generation and the moment of intersection of the photoelectric sensor's sensitivity zone. Angular coordinates of the spray edges, required for calculating the spray angle, are obtained by varying the opening angle of the sector reflectors and the corresponding sensor placement. Spray dispersion is assessed using oscillograms of signals received from the sensors. The technical result of this utility model is to improve the accuracy, reliability, and completeness of diagnostic information on injector spray parameters through the use of photoelectric sensors with automated positioning at various distances relative to the fuel injection zone.

Description

[0001] The utility model relates to engine manufacturing, in particular to stands for testing and adjusting injectors, and can be used at diesel engine manufacturing plants, service centers and maintenance stations.

[0002] A known rig for testing and adjusting injectors [RU Patent No. 80514, IPC F02M 65 / 00, published September 3, 2008], which includes a mounting stand with clamps for the injectors being tested, an injection chamber, a pump with a hydraulic accumulator, and a fuel line with a pressure gauge, a receiving tank with inlet ports, and a coaxially mounted injection chamber, all interconnected and mounted on a receiving tank. The injector clamps are mounted coaxially to the longitudinal axis of the injection chamber and are vertically movable. This rig also contains an automatic control system that provides control over the testing process.

[0003] The disadvantages of the analog include the inability to measure the dynamic and geometric parameters of the fuel spray, as well as to assess the quality of fuel atomization by the injector. The device's measurement unit determines the main characteristics of the fuel injection process—cycle flow, unevenness of cycle flow across the nozzle openings, initial pressure, and maximum injection pressure—but lacks the means to control the shape, structure, and velocity of the fuel spray in space.

[0004] The closest technical solution adopted as a prototype is a test rig for diesel injectors [RU Patent No. 237134, IPC F02M 65 / 001, published on September 11, 2025], which includes a mounting rack with clamps for fixing the tested injector, an injection chamber, a fuel pump, a high-pressure fuel pump with a hydraulic accumulator, a receiving tank with inlet openings and a coaxially mounted injection chamber, as well as an automatic control system that ensures the control of the fuel supply process. A sector receiver with sector reflectors equipped with electromagnetic drives, on which photoelectric sensors are installed, is designed to record the parameters of the fuel torch - its propagation speed, opening angle and fuel atomization dispersion.

[0005] A disadvantage of the specified prototype is that the photoelectric sensors have a fixed position relative to the sector reflector. At the same time, it was established (El Marnissi Y., Hwang J. Microscopic imaging on diesel spray and atomization process / / Processes. - 2024. - Vol. 12, no. 2. - Article 359. - DOI: 10.3390 / pr12020359) that the structure of the fuel plume changes significantly with increasing distance from the injector nozzle opening: the droplet density, degree of scattering, shape and propagation velocity change. The fixed position of the sensors does not allow obtaining information on the characteristics of the fuel plume in different sections, which limits the possibilities of technical diagnostics and scientific research.

[0006] The purpose of this utility model is to expand the functionality of the test bench, improve diagnostic information, and enable fuel spray analysis at various distances from the injection zone. This goal is achieved by the bench comprising a mounting stand with clamps for the injectors being tested, an injection chamber, a pump with a hydraulic accumulator, a fuel line with a pressure gauge, a receiving tank with inlet ports, coaxially positioned with the injection chamber, and an automatic control system with associated units and sensors. A sector receiver is installed within the injection chamber, with sector reflectors located in the upper section, driven by electromagnetic actuators.

[0007] A new feature of the diesel injector test rig is that each photoelectric sensor is equipped with a linear stepper motor with a built-in lead screw, with radial movement along guides mounted on a sector reflector. This design allows for varying the distance from the sensor to the injector nozzle during testing and recording fuel spray parameters in various spatial cross-sections. The linear stepper motors are connected to an automatic control system, enabling automated positioning of the photoelectric sensors and the acquisition of an expanded set of measurement data.

[0008] The essence of the utility model is explained by drawings.

[0009] Fig. 1 shows the general view of the test rig for diesel injectors; Fig. 2 is a structural diagram of the rig; Fig. 3 is a diagram of the relative position of the injector and linear stepper motors; Fig. 4 is a diagram of the arrangement of the photoelectric sensors before testing the injector (the dotted line indicates the extreme position of the photoelectric sensor on the sector reflector); Fig. 5 is a diagram of the arrangement of the photoelectric sensors during testing the injector.

[0010] The stand contains a receiving tank 1, an electromagnetic injector 3 with a connector 4. The injector 3 is fixed on the mounting post 2 in clamps 5, 6 and is equipped with a nipple 7 for supplying fuel from the high-pressure pipeline 8 and a remote pressure sensor 9. An injection chamber 10 is fixed on the receiving tank 1 and a sector receiver 11 with sector deflectors 12 is installed concentrically inside it. The number of sector deflectors 12 corresponds to the number of nozzle holes of the injector 3. Electromagnetic drives 13 are fixed on the outer part of the injection chamber 10, connected to the sector deflectors 12.On the outer side of the sector reflectors 12 there are guides 30 and linear stepper motors 31 with a built-in lead screw, wherein the movable slider 32 is located between the guides 30, and the photoelectric sensor 14 is fixed on the slider 32 on the inner side of the sector reflector 12, which makes it possible to change the distance from the photoelectric sensor 14 to the nozzle opening of the injector 3 in the direction along the fuel atomization axis.

[0011] In the lower part of the sector receiver 11, drain holes 15, a hydrostatic pressure sensor 16, and group electrically controlled valves 17 are located, connected to the automatic control system of the test bench. Inlet holes 18 are made in the upper part of the receiving tank 1. The test bench is equipped with a drive 19, ensuring the operation of the fuel pump 20 and the high-pressure fuel pump (HPFP) 21, as well as a drive shaft speed sensor 22. Fuel is supplied by the fuel pump 20 from the fuel filter 23 in the receiving tank 1 through the check valve 24 to the HPFP 21 and then to the hydraulic accumulator 25.

[0012] The automatic control system consists of measurement units 26, processing and analysis units 27, and control units 28, connected to a personal computer (processor) 29. The control units are connected to a rotation speed sensor 22, a remote pressure sensor 9, a hydrostatic pressure sensor 16, as well as to linear stepper motors 31 and photoelectric sensors 14, providing automated positioning of the sensors and recording of fuel torch parameters.

[0013] The diesel injector test rig operates as follows. Before testing, the rig is prepared for operation. Filtered diesel fuel is poured through inlet openings 18 in receiving tank 1. Injector 3 is mounted in clamps 5 and 6 coaxially within injection chamber 10, with high-pressure line 8 connected to fitting 7 and connected to control unit 28 via connector 4.

[0014] In the initial state, the sectors of the receiver 11 are closed by sector reflectors 12, the opening angle of which is regulated by electromagnetic drives 13. Photoelectric sensors 14 are in the initial positions corresponding to the minimum distance from the nozzle openings of the injector 3. The automatic control system for the operation of the stand is turned on.Using the program setter, the required injector test program is selected and the required spatial cross-section for registering the fuel torch is set, after which the control unit 28 is started, from which a signal is sent to the electromagnetic drives 13 to open the sector reflectors 12, the linear stepper motors 31 are activated, which, by means of a movable slider 32 along guides 30, move the sensors to the specified radial positions, the drive 19 of the fuel pump 20 and the high-pressure fuel pump 21 is turned on, thereby ensuring the supply of fuel from the receiving tank 1 through the filter 23, the check valve 24 and the hydraulic accumulator 25 to the injector 3. The rotation speed of the drive shaft 19 is controlled using the speed sensor 22.Upon reaching a predetermined fuel pressure in accumulator 25, determined by remote pressure sensor 9, a control signal from control unit 28 opens injector 3's electromagnetic valve, initiating the injection process. The fuel spray from injector 3 enters injection chamber 10 and is detected by photoelectric sensors 14 mounted on sector reflectors 12. When the spray crosses the detection zone of photoelectric sensor 14, the precise time and coordinates of the intersection are recorded. Knowing the distance between the injector and sensor, as well as the time from the start of signal transmission until the intersection is detected, measuring unit 26 calculates the average speed of the fuel spray.

[0015] Depending on the opening angle of the sector reflectors 12 and the corresponding position of the photoelectric sensors 14, the boundaries of the fuel plume are determined. Photoelectric sensors 14 register the moments when the fuel plume crosses their detection zones, allowing the angular coordinates of the plume edges to be determined. Based on this data, measuring unit 26 calculates the fuel plume's opening angle.

[0016] During injector testing, oscillograms of signals received from photoelectric sensors 14 are displayed in real time on the personal computer (PC) screen 29. Visual analysis of these oscillograms provides information on the fuel spray dispersion. A smooth increase and decrease in the signal may indicate a uniform droplet distribution within the spray. However, abrupt changes in the signal shape may indicate unevenness or dense "ridges" in the spray, providing the opportunity for a more detailed analysis and subsequent adjustments to the fuel atomization process.

[0017] Placing photoelectric sensors 14 in different positions allows for a detailed study of the shape and structure of the fuel spray. Mounting them around injector 3 allows for determination of the uniformity and symmetry of fuel atomization. Mounting photoelectric sensors 14 at different distances from injector 3 along the spray axis helps study how the fuel spray changes with distance from the injection point, including possible dispersion and changes in its velocity.

[0018] Hydrostatic pressure sensors 16 are installed in each sector of the sector receiver to analyze the fuel pressure distribution. The atomized fuel from each orifice of the injector 3 enters the corresponding sector of the sector receiver 11 and is drained through the open drain holes 15 into the receiving tank 1. After a command from the control unit 28, the drain holes 15 and the group electrically controlled valves 17 are closed, and the hydrostatic pressure sensors 16 are connected to the measuring unit 26. A timer and cycle counter are activated, recording the number of fuel delivery cycles and the pressure in each sector. Based on the received data, the measuring unit 26 calculates the cyclic fuel delivery through each nozzle hole of the injector 3, the total delivery, the distribution unevenness, as well as the injection start pressure and the maximum fuel delivery pressure. The results are analyzed in the processing and analysis unit 27.At the end of the tests, the control system switches off pumps 20 and 21, closes sector reflectors 12 and completes the analysis and adjustment process.

[0019] The technical result of this utility model is to improve the accuracy, reliability, and completeness of diagnostic information on injector spray parameters through the use of photoelectric sensors with automated positioning at various distances relative to the fuel injection zone. This design enables recording parameters in various spatial cross-sections, ensuring a more accurate determination of the dynamic and geometric characteristics of the fuel spray, as well as a reliable assessment of the uniformity of fuel delivery through the injector nozzle openings.

Claims

A test rig for injectors, including a mounting stand with clamps for the injectors being tested, an injection chamber, a fuel feed pump, a high-pressure fuel pump with a hydraulic accumulator, a receiving tank with inlet openings, coaxially with which the injection chamber is installed, an automatic control system, while inside the injection chamber, coaxially with it, a sector receiver is installed, in the upper part of which sector reflectors with electromagnetic drives and photoelectric sensors installed thereon are made, characterized in that the photoelectric sensors are equipped with linear stepper motors with built-in lead screws, providing the ability to move the sensors relative to the injector along the spray axis.

Images