Fuel injector dosimeter

Abstract

The utility model provides an oil injector dosimeter. The oil injector dosimeter comprises an oil injector, a metering chamber, a piston assembly, a back pressure system, an encoder and a control circuit. An oil injection opening of the oil injector communicates with the closed metering chamber, and the first end of the piston assembly is located in the metering chamber and moves in the axial direction in the oil injection process. The backpressure system provides stable backpressure for the piston assembly, the encoder encodes the displacement of the piston, and the control circuit receives encoding data output by the encoder and calculates the single-time or continuous oil injection flow of the oil injector. The fuel injection flow can be accurately metered, and high precision and reliability are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid measurement and detection, and in particular to a flowmeter device for precisely detecting the flow rate of a diesel injector by using an encoder. Background Art

[0002] At present, the flow rate detection means of diesel injectors mainly rely on gear flowmeters, and a small number use a magnetic encoding cylinder structure for flow rate measurement. However, traditional gear flowmeters have exposed many deficiencies in practical applications:

[0003] First of all, gear flowmeters are easily affected by the differences in diesel concentration and quality, the manufacturing errors of the gaps between gears and the housing, and the assembly accuracy during metering. When the frictional forces between the gears and diesel are unbalanced, it is easy to cause the gears to rotate unstably, resulting in fluctuations and inaccuracies in the metering data. In the case of low flow rates or inappropriate gear clearances, serious measurement leakage may also occur, directly reducing the accuracy and stability of metering.

[0004] In addition, gear flowmeters have strict requirements for diesel cleanliness. Once they contain trace impurities, it is easy to cause gear jamming or even damage, increasing the maintenance difficulty and cost. At the same time, gear flowmeters usually need to obtain metering data once after the gears rotate one week, resulting in a slow detection response speed and making it difficult to achieve real-time and accurate detection of the single or instantaneous injection volume of the injector.

[0005] Another type of magnetic encoding cylinder flowmeter is relatively feasible in principle, but generally adopts a spring reset structure. The inconsistent compression ratios and compression forces of the springs and the long-term fatigue phenomenon make it difficult to guarantee the batch stability and interchangeability of the device. Re-calibration is often required during replacement or maintenance, which is time-consuming and laborious. At the same time, the mechanical properties of the springs determine that the reverse pressure received by the cylinder at different positions is not constant, which has an adverse impact on the metering accuracy and long-term stability.

[0006] In summary, traditional gear flowmeters have problems such as leakage, strict assembly and processing requirements, insufficient measurement accuracy and response speed, and difficult maintenance; magnetic encoding cylinder flowmeters face problems of stability, interchangeability, and maintenance calibration after long-term use. These problems limit the high-precision, real-time measurement and large-scale stable application requirements of existing flowmeters for diesel injectors in actual use.

[0007] In view of the above deficiencies, there is an urgent need for a flowmetering solution for injectors that does not rely on the accuracy of gear clearances, can avoid the influence of unstable mechanical properties of springs, and can achieve high-precision, real-time, stable and reliable performance. Summary of the Invention

[0008] The present invention aims to solve a number of technical problems existing in the use of existing diesel injector flow meters, including the difficult gap control, leakage, and insufficient low-flow accuracy of gear-type flow meters, as well as the batch stability and long-term use and maintenance problems of traditional magnetic-encoded cylinder flow meters due to the spring reset characteristics. Through the technical solution of the present invention, high-precision, real-time, leak-free, and extra-resistance-free detection of the diesel injector flow can be achieved, and the stability, interchangeability, and long-term use reliability of the equipment can be improved.

[0009] To achieve the above object, the present invention proposes a new type of injector dosimeter, the core of which lies in the combination of a single-acting sealed cylinder metering structure, a backpressure system, magnetic encoder detection technology, and a control circuit to achieve precise, stable, and real-time metering of the fuel injection flow of the injector.

[0010] The injector dosimeter of the present invention generally includes:

[0011] An injector and a metering chamber, the fuel injection port of the injector is communicated with a sealed metering chamber. When the injector injects fuel, the fuel enters the metering chamber and pushes the piston assembly arranged in the metering chamber, thereby metering the fuel injection volume.

[0012] A piston assembly and a sealing structure, the first end of the piston assembly is located in the metering chamber and moves axially along the metering chamber under the action of fuel injection. The piston assembly includes a plunger and a sealing ring, which are used to achieve good sealing when the piston moves relative to the metering chamber and the guide post, avoiding leakage. Such a sealing structure ensures a stable and leak-free metering space even at low flow rates and extremely low pressures.

[0013] A backpressure system, a stable backpressure is provided on the other side of the piston assembly through the backpressure system. Different from the traditional cylinder that uses a spring for reset, the present invention uses an independent oil pump system to generate a constant and controllable backpressure, forming a stable reverse pressure on the piston to ensure that the piston can obtain consistent pressure conditions at any position. This backpressure method eliminates the influence of the non-linear mechanical characteristics of the spring, simplifies the structure, and improves the interchangeability of batch production and the long-term use stability.

[0014] An encoder and a sensor unit, the present invention uses a magnetic encoder to detect the displacement of the piston assembly in real time. The piston assembly drives a coding disk (with a coding magnetic strip) to move through the plunger and the displacement conduction block, and a sensor (such as a Hall sensor) installed in the main body can sense the displacement amount of the coding magnetic strip in real time, thereby obtaining the accurate position data of the piston. In addition, upper and lower limit Hall sensors can be arranged in the main body to limit the piston stroke range and provide upper and lower limit signals to the control circuit. Through the cooperation of the magnetic encoder and the sensor, the present invention can achieve extremely high-precision and real-time displacement induction.

[0015] The control circuit is electrically connected to the encoder and the sensor, receives piston displacement encoded data and upper and lower limit signals, and calculates the instantaneous flow rate or single injection volume of the injector through built-in algorithms. The control circuit is also coupled with the backpressure system (including an independent oil pump) and can adjust the backpressure to stabilize the piston movement range and metering accuracy. Through this closed-loop control strategy, the present invention can accurately measure and control the flow rate of the injector under various working conditions.

[0016] The return valve and discharge structure: After metering is completed, the oil in the metering chamber can be discharged through the return valve under the action of the piston assembly, restoring the metering chamber to its initial state and preparing for the next metering. This design ensures the rapid restoration of the metering cycle and continuous high-efficiency detection.

[0017] Compared with the prior art, the present invention has the following remarkable advantages:

[0018] 1. No leakage and high precision: By adopting single-acting cylinder sealed metering and constant backpressure control, the present invention eliminates the leakage and instability factors caused by gear clearance in terms of structure and can achieve accurate resolution of tiny flow rates (such as at the level of 0.01 ml / min).

[0019] 2. With real-time detection ability: Utilizing the real-time displacement acquisition ability of the magnetic encoder, continuous and real-time flow rate data can be obtained during each injection process of the injector; this significantly improves the detection efficiency and the ability to analyze the single injection behavior of the injector.

[0020] 3. Stability and interchangeability: The present invention avoids the use of traditional cylinder springs, eliminating problems such as spring fatigue and inconsistent deformation rates, and greatly improving the interchangeability of the device in mass production and its stability during long-term use.

[0021] 4. Convenient maintenance and low cost: Since backpressure drive is adopted instead of spring reset, the disassembly, installation and maintenance of the system are simplified, and it can be used for a long time with one calibration, reducing the frequency and cost of secondary calibration.

[0022] 5. Wide applicability: The present invention can achieve single injection metering, simultaneous acquisition of fuel injection / return, detection of opening pulse width (MDP) and opening pressure (NOP), and can further meet the demand for generating flow correction compensation codes under high-definition injection conditions, expanding a wider application scenario for the precise control and detection of injectors.

[0023] In summary, by organically combining a single-acting cylinder, constant backpressure and magnetic encoder detection technology in a closed metering space, the present invention overcomes the deficiencies in the prior art, meets the requirements for high-precision, stable and real-time injector flow rate detection, and has broad industrial application prospects. Description of the Drawings

[0024] Figure 1 It is the three-dimensional external structure of the fuel injector flowmeter, showing the overall layout of the device and the positions of components.

[0025] Figure 2 It is a sectional view of the fuel injector flowmeter, marking the main components and their internal structural relationships.

[0026] Figure 3 It is a circuit block diagram of the fuel injector flowmeter, showing the signal interaction relationships among the magnetic encoder, control circuit, Hall sensor, and fuel pump. Specific Embodiments

[0027] The following further elaborately describes the implementation scheme of the present application in conjunction with the accompanying drawings, so as to facilitate those skilled in the art to understand the technical solution of the present application.

[0028] See Figures 1 to 3 , the overall structure of the fuel injector dosimeter 400 of the present invention includes a fuel injector, a metering chamber 200, a piston assembly 220, a backpressure system 230, an encoder 250 (including a code disk 260 and a sensor 270), a control circuit 280, and a return structure, etc., and can accurately measure and output fuel injection data in real time during the fuel injection process of the diesel fuel injector 100.

[0029] Overall Structure and Working Principle

[0030] The fuel injector dosimeter of the present invention is mainly composed of a main body 410 (body structure) and a plurality of functional components installed in the main body. The main body can be a cuboid structure, and an axially extending metering chamber 200 and a guide post channel 210 are machined inside. The fuel injection port 101 of the fuel injector 100 is communicated with the metering chamber 200. When the fuel injector 100 injects fuel into the metering chamber 200, it will push the piston assembly 220 in the metering chamber 200 to move in the axial direction. By monitoring the displacement of the piston assembly 220, the single or continuous fuel injection volume of the fuel injector 100 can be obtained.

[0031] The piston assembly is driven by a backpressure system 230 that can provide a constant and controllable backpressure. Different from the traditional structure that uses a spring as the source of reset and backpressure, the present invention maintains and adjusts the backpressure system 230 through an independent fuel pump 240 and an oil circuit regulation module 240. This can ensure that the piston assembly 220 bears a stable and uniform reverse pressure at different positions during the metering process, improving the metering accuracy and repeatability.

[0032] When the piston assembly 220 moves, it drives the encoding disk 260 of the encoder to move. The encoder 250 is composed of the encoding disk 260 (with an encoding magnetic strip) installed on the piston assembly 220 and the Hall sensor 270 fixedly arranged in the main body. During the fuel injection process, the piston assembly 220 moves with the fuel input, driving the encoding disk 260 to displace synchronously. The Hall sensor 270 senses the change in the position of the encoding magnetic strip and converts it into an electrical signal to be transmitted to the control circuit 280. The control circuit 280 calculates the displacement in real time and then calculates the fuel injection quantity.

[0033] In addition, upper and lower limit Hall sensors 290 and 300 are also arranged in the main body, which are used to determine the upper and lower limit positions of the piston assembly 220 within the stroke range. When the piston assembly 220 reaches the preset upper and lower limit positions, the Hall sensors 290 and 300 send corresponding signals to the control circuit 280 to achieve the calibration and protection of the stroke range of the piston assembly 220. Based on this, the control circuit 280 controls the oil pump 240 to maintain the controllability and safety of the movement stroke of the piston assembly 220.

[0034] The following details the specific structures and functions of each component according to the system composition:

[0035] Fuel injector

[0036] The fuel injection port of the fuel injector 100 is connected to a sealed metering chamber 200. When the external diesel fuel injector 100 injects oil into the metering chamber 200, the amount of oil in the metering chamber 200 increases and pushes the piston assembly 220 to move towards the back pressure side. After the fuel injection ends, the remaining oil in the metering chamber 200 is discharged through the return valve 120 to restore the initial state of the metering chamber 200 again, preparing for the next metering cycle. The return valve 120 generally exists in the form of a one-way valve or a solenoid valve. After the detection ends, the return channel is opened, and the excess oil in the metering chamber 200 flows back to the external oil circuit or the oil storage cavity, thus realizing cyclic metering.

[0037] Piston assembly

[0038] The piston assembly 220 includes a plunger 221, a first plunger seal ring 222, and a second seal ring 223. The first end of the piston assembly 220 is arranged inside the metering chamber 200, and the first plunger seal ring 222 is used for sealing between the plunger 221 and the inner wall of the metering chamber 200. The second end of the piston assembly 220 is arranged inside the guide post 210 in the main body, and the second seal ring 223 is used for sealing the gap between the piston assembly 220 and the guide post 210.

[0039] Furthermore, the first or second seal ring is a UNY type rubber ring seal.

[0040] Further, the diameter of the plunger 221 is smaller than the diameter of the metering chamber 200, and at the same time, the diameter of the plunger 221 is smaller than the diameter of the inner cavity of the guide post 210. Further, both the metering chamber 200 and the inner cavity of the guide post 210 are cylindrical spaces 201. Further, the plunger 221 is provided with a hollow blind hole 224, which is used to reduce the overall mass of the plunger 221, increase the acting area of the plunger 221 with the oil in the back pressure system 230, and improve the working stability and response speed of the plunger 221.

[0041] During the fuel injection process, the pressure in the metering chamber 200 rises and pushes the plunger 221 to move in the direction of the back pressure. The first plunger seal ring 222 ensures that there is no oil leakage when the plunger 221 moves along the metering chamber 200. The guide post 210 ( Figure 3 marked as 7 in the figure) serves as the guiding structure of the piston assembly 220, and the inner wall thereof and the plunger are sealed by the second seal ring 223 to prevent leakage between the piston assembly 220 and the guide post 210.

[0042] Conduction block

[0043] The accommodating space 20 is used to arrange the conduction block 226 and the coding disk 260 on the conduction block 226. The plunger 221 and the conduction block 230 are provided with holes for fixing, and the two can be fixed together by all conventional technical solutions known to those skilled in the art. On the upper and lower sides of the conduction block 226, two walls 227 are respectively arranged to physically limit the maximum stroke of the conduction block 226.

[0044] Back pressure system

[0045] The guide post 210 is machined with a through hole or opening 211 communicating with the oil circuit of the back pressure system 230, which is used to guide the pressure oil provided by the independent oil pump 240 into the inner cavity of the guide post 210 or the corresponding back pressure chamber. The back pressure system 230 consists of an oil pump 240, a Hall sensor 290 and a control circuit 280 to form a closed-loop control system. The control circuit 280 receives the position signal of the piston assembly 220 fed back by the encoder 250 in real time and the limit signal 290 fed back by the Hall sensor, and dynamically adjusts the output pressure of the oil pump 240. Through this mechanism, the back pressure system 230 provides a constant and controllable back pressure for the piston assembly 220, ensures the stability of the metering chamber pressure, thereby improving the metering accuracy and the reliability of the system operation. During the fuel injection process, the back pressure system can effectively adjust the back pressure, prevent the piston assembly from exceeding the movement range, and at the same time maintain the stability of the system and the accuracy of metering during long-term operation.

[0046] It should be noted that some oil circuits and the mechanical structure of the oil pump in the backpressure system are not shown in detail in this specification and the accompanying drawings. However, those skilled in the art can easily implement the corresponding backpressure oil circuit layout and the functional connection with the independent oil pump based on their own experience and conventional technical means. Since such implementation methods have no substantial impact on the overall technical solution of the present invention, even if not explicitly shown in the drawings, it will not weaken the clarity and integrity of the description of this application.

[0047] For example, those skilled in the art can connect the independent oil pump to the guide post through the internal oil circuit and the solenoid valve module according to the metering chamber specifications, backpressure control requirements, and control circuit interface, so as to achieve the required backpressure regulation function.

[0048] Encoder and position detection

[0049] An encoding disk 260 is installed on the displacement conduction block 230. An encoding magnetic strip is adhered to the surface of the encoding disk 260 and is arranged opposite to the Hall sensor 270 installed in the main body. When the piston assembly 220 moves, the encoding disk 260 linearly displaces accordingly, and the Hall sensor 270 senses the magnetic field change of the magnetic strip and generates an electrical signal corresponding to the displacement amount and outputs it to the control circuit 280. The control circuit 280 analyzes this signal into the real-time position data of the piston assembly 220, thereby accurately calculating the fuel injection amount.

[0050] In addition, the upper limit Hall sensor 290 and the lower limit Hall sensor 300 are respectively used to detect the highest point and the lowest point of the stroke of the piston assembly 220. When the piston assembly 220 moves to the upper and lower limit positions, the corresponding limit Hall sensors 290 and 300 output signals to the control circuit 280, and the control circuit 280 can calibrate and control the reference stroke range of the piston assembly 220 accordingly.

[0051] It should be noted that the encoder described in the present invention is not limited to the form of a magnetic encoder. In the implementation process, those skilled in the art can select other types of encoders according to actual needs, such as optical encoders, inductive encoders, resistive linear displacement sensors, or laser rangefinders, etc. These alternative solutions can provide equally feasible displacement detection functions for the device under different usage conditions or accuracy requirements.

[0052] It should be noted that the limit sensor is not limited to the Hall sensor, and other types can also be selected according to actual needs, such as optical encoders, inductive position sensors, resistive linear displacement sensors, laser rangefinders, magnetostrictive displacement sensors, ultrasonic position sensors, and capacitive position sensors.

[0053] Control circuit

[0054] The control circuit 280 is electrically connected to the encoder 250, the upper / lower limit Hall sensors 290, 300, and the oil pump 240 motor. The control circuit 280 is configured to:

[0055] Calculate the instantaneous flow rate and the single injection volume of the injector 100 based on the displacement encoding signal output by the encoder 250.

[0056] Furthermore, in this embodiment, the single injection volume and the instantaneous flow rate can be calculated based on the relationship between the displacement of the plunger 221 and the cross-sectional area of the metering chamber 200. Specifically as follows:

[0057] When the injector completes one injection, the plunger 221 moves from the initial position to the final position. Let the displacement be ΔL, then the volume of fuel injected in a single injection is:

[0058] V injection = A·ΔL where:

[0059] V injection Is the single injection volume (unit: mL or L);

[0060] A is the effective cross-sectional area of the metering chamber (unit: m 2 );

[0061] ΔL is the axial displacement distance of the plunger corresponding to this injection process (unit: m).

[0062] During the injection process, the instantaneous flow rate depends on the change in the displacement of the plunger per unit time. At any moment t, let the displacement speed of the plunger be Then the instantaneous flow rate is:

[0063] Where:

[0064] Q(t) is the instantaneous flow rate (unit: m 3 / s or L / s);

[0065] Is the rate of change of the plunger displacement with time, that is, the plunger movement speed (unit: m / s);

[0066] A is the same as the above definition.

[0067] The control circuit is further configured to establish a reference range for the movement of the piston assembly based on the upper and lower limit Hall sensor signals, and monitor, protect, and limit the piston stroke during the metering process.

[0068] The control circuit is further configured to control the output pressure of the oil pump to keep the back pressure within an ideal range, thereby ensuring that the piston assembly is under balanced force and the data is stable and reliable during operation.

[0069] Working process

[0070] Reference Figure 3 Referring to the signal and control flow shown in Figure 3 , the working logic of the present invention preferably includes the steps of:

[0071] In the initial state, the piston assembly 220 is located near the upper limit position. The upper and lower limit Hall sensors 290 and 300 confirm the initial reference position of the piston 220 by outputting position signals to the control circuit 280. At this time, the control circuit 280 has established communication with the independent oil pump 240 and applied a suitable initial backpressure system 230 to the piston assembly 220.

[0072] When the injector 100 starts injecting fuel, the fuel enters the metering chamber 200 and pushes the piston assembly 220 to move downward. The coding disk 260 and the magnetic strip 261 linked to the piston assembly 220 then generate displacement changes. The Hall sensor 270 installed in the main body senses the displacement amount in real time and transmits the corresponding coding signal to the control circuit 280.

[0073] After receiving the displacement data output by the encoder 250, the control circuit 280 queries the upper and lower limit Hall sensors 290 and 300 according to a pre-set process to obtain the upper and lower limit reference signals of the current piston position. According to the real-time displacement amount of the piston assembly 220, the upper and lower limit feedback signals, and the established metering requirements, the control circuit 280 calculates the fuel injection amount and the instantaneous flow rate during this injection process.

[0074] After the fuel injection is completed, the control circuit 280 instructs the return valve 120 to open, and at the same time controls the oil pump to maintain the backpressure to discharge the excess oil in the metering chamber 200. Subsequently, the piston assembly 220 returns to the initial position under the action of the constant and controllable backpressure system 230, preparing for the next fuel injection metering.

[0075] During long-term operation, if the piston assembly 220 approaches the upper and lower limits during movement, the Hall sensors 290 and 300 will send position signals to the control circuit 280 again. The control circuit 280 adjusts the output pressure of the oil pump 240 in real time accordingly to maintain the stability of the backpressure system 230 and ensure that the movement range of the piston assembly 220 does not exceed the preset limit. Through this closed-loop control strategy, the fuel injector dosimeter of the present invention can continuously ensure the metering accuracy and operation safety under various working conditions.

[0076] This application eliminates the spring nonlinear characteristics and gear leakage problems through constant backpressure control, achieving high precision and long-term stability.

[0077] The encoder obtains displacement data in real time, enabling rapid response and accurate metering of the fuel injection amount of the injector.

[0078] Define the reference stroke range of the piston assembly using a limit Hall sensor to achieve safety and controllability during the movement process.

[0079] In summary, through the detailed description of the components and structures shown in the accompanying drawings, the specific embodiments of the present invention effectively support the technical solutions of the foregoing claims. This embodiment provides an injector dosimeter with a compact structure, high precision, good real-time performance, and good controllability, providing an innovative and practical solution for the field of diesel injector flow detection.

Claims

1. An injector dosimeter, characterized in that, Comprising: An injector, whose injection orifice communicates with a closed metering chamber; A piston assembly, whose first end is located within the metering chamber and moves along the axial direction of the metering chamber during the injection process; A backpressure system for providing backpressure to the piston assembly; An encoder for encoding the displacement of the piston assembly caused by injection; A control circuit, electrically connected to the encoder, for receiving the encoded data representing the piston displacement output by the encoder and calculating the single or continuous injection flow rate of the injector based on this encoded data.

2. The injector dosimeter according to claim 1, characterized in that, The piston assembly includes a plunger and a first plunger seal provided on the outer periphery of the plunger, and the first plunger seal is used to seal the gap between the plunger and the inner wall of the metering chamber when the plunger moves along the metering chamber.

3. The injector dosimeter according to claim 2, characterized in that, It further includes a main body, a guide post is provided within the main body, and the second end of the piston assembly is disposed within the guide post; the piston assembly further includes a second seal, and this second seal is used to seal the gap between the piston assembly and the guide post when the piston assembly moves relative to the guide post.

4. The injector dosimeter according to claim 3, characterized in that, The plunger is connected to a displacement transmission block; a coding disk is mounted on the surface of the displacement transmission block; a sensor is fixedly provided within the main body for sensing the displacement amount of the coding disk to generate a coded signal.

5. The injector dosimeter according to claim 4, characterized in that, The encoder is a magnetic encoder, and the coding disk includes a coded magnetic strip; the sensor includes a Hall sensor for sensing the movement of the coded magnetic strip and outputting an electrical signal corresponding to this displacement.

6. The injector dosimeter according to claim 4, characterized in that, An upper limit Hall sensor and a lower limit Hall sensor are further provided within the main body for detecting the upper and lower limit positions of the piston assembly and outputting corresponding position detection signals.

7. The injector dosimeter according to claim 6, characterized in that, Both the upper limit Hall sensor and the lower limit Hall sensor are electrically connected to the control circuit, and the control circuit determines the stroke range of the piston assembly based on the signals output by the upper and lower limit Hall sensors and monitors and limits the movement stroke of the piston assembly.

8. The injector dosimeter according to claim 7, characterized in that, An opening communicating with the backpressure system is provided on the guide post, and the backpressure system includes an independent oil pump; the independent oil pump is electrically coupled to the control circuit, and the control circuit is configured to control the oil pump to provide a stable and adjustable backpressure to the piston assembly.

9. The injector dosimeter according to claim 8, characterized in that, The control circuit controls the output of the oil pump according to the signals of the encoder and the upper and lower limit Hall sensors, so that the stroke range of the piston assembly is maintained within the stroke range defined by the upper and lower limit Hall sensors.

10. The injector dosimeter according to claim 1, characterized in that, The injector includes a return valve. After metering is completed, when the piston assembly is reset under the action of backpressure, the oil within the metering chamber is discharged to the outside of the metering chamber through the return valve.

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