Method and structure for measuring fuel quantity of fuel injector

Abstract

The invention provides a fuel injector fuel quantity measuring method and structure, and relates to the technical field of internal combustion engine fuel injection. The fuel injector oil quantity measuring method comprises the steps that the measured temperature and the measured flow of oil sprayed out of a fuel injector are obtained; the average volume flow at the corrected temperature is obtained according to the measured temperature and the measured flow; acquiring a flow coefficient corresponding to the average volume flow; and calculating the accurate flow ejected by the fuel injector according to the average volume flow and the flow coefficient. According to the method for measuring the fuel quantity of the fuel injector, the influence of temperature on flow measurement is fully considered, the flow is further corrected through the flow coefficient after temperature compensation correction, and therefore the accuracy and reliability of flow data obtained through measurement can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of internal combustion engine fuel injection, and in particular to a fuel injector fuel quantity measurement method and structure. Background Art

[0002] The injector is an important component in the internal combustion engine that injects fuel into the combustion chamber for power conversion. For example, in the current diesel-methanol dual-fuel engine, the methanol injection system is the power source of the engine. The methanol injector is one of the core components of the high-pressure common rail system. Its working performance is directly related to the overall performance of the entire high-pressure common rail system. Therefore, it is necessary to test the fuel injector to evaluate its performance, among which the flow rate test is one of the most important tests.

[0003] At present, single injection test is generally adopted in clean fuel injection test equipment, and the main test equipment used is single injection measuring instrument. This test method is cumbersome and time-consuming. In addition, the flow data obtained by the existing measurement method has poor accuracy and low reliability, which has an adverse impact on the subsequent fuel system product development and performance verification. Summary of the invention

[0004] The object of the present invention is to provide a method for measuring the fuel quantity of a fuel injector, which can improve the technical problems of poor fuel injection quantity measurement accuracy and low reliability in the prior art.

[0005] Another object of the present invention is to provide a fuel injector oil quantity measuring structure, which can improve the technical problems of poor fuel injection quantity accuracy and low reliability in the prior art.

[0006] The embodiments of the present invention can be implemented in the following ways:

[0007] A fuel injector oil quantity measurement method, the fuel injector oil quantity measurement method comprising:

[0008] Obtain the measured temperature and flow rate of the oil sprayed by the fuel injector;

[0009] Obtaining an average volume flow rate at a corrected temperature according to the measured temperature and the measured flow rate;

[0010] Obtaining a flow coefficient corresponding to the average volume flow rate;

[0011] The accurate flow rate sprayed by the fuel injector is calculated according to the average volume flow rate and the flow coefficient.

[0012] Optionally, the step of obtaining the average volume flow rate at the corrected temperature according to the measured temperature and the measured flow rate comprises:

[0013] The measured flow is converted into the volume flow at the corrected temperature, and the conversion formula is:

[0014]

[0015] Among them, Q T1 is the volume flow rate at the corrected temperature; Q T2 is the measured flow rate; ρ T2 is the oil density at the measuring temperature; ρ T1 is the oil density at the corrected temperature;

[0016] The average volume flow rate at the corrected temperature is calculated based on the volume flow rate, and the calculation formula is:

[0017]

[0018] Among them, ΔQ T1 is the average volume flow rate; t is the duration corresponding to a metering cycle.

[0019] Optionally, before the step of obtaining the flow coefficient corresponding to the average volume flow, the fuel injector oil quantity measurement method further includes:

[0020] Divide the flow interval and calculate the flow coefficient of each flow interval respectively;

[0021] The step of obtaining a flow coefficient corresponding to the average volume flow rate comprises:

[0022] The flow interval to which the average volume flow belongs is determined, and the flow coefficient corresponding to the flow interval is used as the flow coefficient corresponding to the average volume flow.

[0023] Optionally, the step of dividing the flow intervals and respectively determining the flow coefficient of each flow interval includes:

[0024] The flow rate interval is divided into the following intervals: (0 ml / min, 100 ml / min), [100 ml / min, 500 ml / min), [500 ml / min, 1000 ml / min), [1000 ml / min, 2000 ml / min), [2000 ml / min, 3000 ml / min) and [3000 ml / min, 4000 ml / min);

[0025] For each flow interval, the weighing method is used to obtain multiple sets of data on the volume flow rate within a metering cycle and the average volume flow rate at the corrected temperature. The volume flow rate Q obtained by the weighing method is T1称重 and the average volume flow rate ΔQ at the corrected temperature T1 Satisfies the following formula:

[0026] Q T1称重 =aΔQ T1 +b;

[0027] Among them, a and b are flow coefficients.

[0028] Optionally, the calculation formula for obtaining the accurate flow rate sprayed by the fuel injector according to the average volume flow rate and the flow coefficient is:

[0029] Q′=aΔQ T1 +b

[0030] Where Q′ is the accurate flow rate; ΔQ T1 is the average volume flow rate; a and b are flow coefficients.

[0031] Optionally, the correction temperature is 40°C.

[0032] A fuel injector oil quantity measuring structure, the fuel injector oil quantity measuring structure comprising:

[0033] A medium metering module, the medium metering module is used to obtain the measured temperature and measured flow rate of the oil sprayed by the fuel injector, and obtain the average volume flow rate at the corrected temperature based on the measured temperature and the measured flow rate; and the medium metering module is also used to obtain the flow coefficient corresponding to the average volume flow rate, and calculate the accurate flow rate sprayed by the fuel injector based on the average volume flow rate and the flow coefficient.

[0034] Optionally, the medium metering module includes a temperature sensor, a flow meter and a controller, and the temperature sensor and the flow meter are electrically connected to the controller; the temperature sensor is used to obtain the temperature of the oil sprayed by the fuel injector and transmit the temperature signal representing the temperature to the controller; the flow meter is used to obtain the flow rate of the oil sprayed by the fuel injector and transmit the measured flow rate representing the flow rate to the controller; the controller is used to obtain the average volume flow rate at the corrected temperature according to the measured temperature and the measured flow rate, and calculate the accurate flow rate sprayed by the fuel injector according to the flow coefficient corresponding to the average volume flow rate and the average volume flow rate.

[0035] Optionally, the temperature sensor is arranged upstream of the flow meter.

[0036] Optionally, the fuel injector oil quantity measurement structure further includes a voltage stabilizing filter module, the voltage stabilizing filter module has an oil inlet and an oil outlet, the oil inlet is used to receive the oil sprayed by the fuel injector, and the oil outlet is connected to the medium metering module;

[0037] The voltage stabilizing and filtering module includes a demisting block, a straight pipe, a pressure stabilizing tank and a throttling device connected in sequence; the oil inlet is the inlet of the demisting block, and the oil outlet is the outlet of the throttling device; the demisting block is used to collect the oil beam sprayed by the fuel injector; the straight pipe is used to weaken the pressure fluctuation of the oil flow; the pressure stabilizing tank is used to store the oil and stabilize the pressure; the throttling device has a throttling hole connecting the pressure stabilizing tank and the oil outlet, and the throttling hole is used to suppress the pulsation impact caused by continuous injection.

[0038] Optionally, the demisting block includes a communication channel and a first chamber and a second chamber arranged on both sides of the communication channel, and the communication channel connects the first chamber and the second chamber; the first chamber forms the oil inlet on a side away from the second chamber, and the second chamber is connected to the straight pipe on a side away from the first chamber;

[0039] The cross-sectional area of ​​the first chamber is larger than that of the second chamber, the cross-sectional area of ​​the second chamber is larger than that of the connecting passage, and one end of the first chamber connected to the connecting passage has a first conical surface, and one end of the second chamber connected to the connecting passage has a second conical surface.

[0040] Optionally, the diameter of the throttling hole is 0.8 mm to 1.2 mm.

[0041] The beneficial effects of the fuel injector oil quantity measurement method and structure provided by the embodiments of the present invention include:

[0042] The embodiment of the present invention provides a fuel injector oil quantity measurement method, which includes obtaining the measured temperature and measured flow rate of the oil sprayed by the fuel injector; obtaining the average volume flow rate at the corrected temperature according to the measured temperature and the measured flow rate; obtaining the flow coefficient corresponding to the average volume flow rate; and calculating the accurate flow rate sprayed by the fuel injector according to the average volume flow rate and the flow coefficient. The fuel injector oil quantity measurement method fully considers the influence of temperature on flow measurement, and further corrects the flow rate through the flow coefficient after temperature compensation correction, so as to effectively improve the accuracy and reliability of the measured flow data.

[0043] The embodiment of the present invention also provides a fuel injector oil quantity measurement structure, which includes a medium metering module, which is used to obtain the measured temperature and measured flow rate of the oil sprayed by the fuel injector, and obtain the average volume flow rate at the corrected temperature according to the measured temperature and the measured flow rate; and the medium metering module is also used to obtain the flow coefficient corresponding to the average volume flow rate, and calculate the accurate flow rate sprayed by the fuel injector according to the average volume flow rate and the flow coefficient. The fuel injector oil quantity measurement structure fully considers the influence of temperature on flow measurement, and further corrects the flow rate through the flow coefficient after temperature compensation correction, so as to effectively improve the accuracy and reliability of the measured flow data. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0045] Figure 1 A schematic structural diagram of a fuel injector oil quantity measurement structure provided according to one aspect of the present invention is shown;

[0046] Figure 2 A schematic cross-sectional structure diagram of a voltage stabilizing filter module in a fuel injector oil quantity measuring structure provided according to one aspect of the present invention is shown;

[0047] Figure 3 A schematic diagram showing the internal structure of a demisting block in a fuel injector oil quantity measuring structure provided according to one aspect of the present invention is shown;

[0048] Figure 4 Shows Figure 2 A magnified schematic diagram of the local structure at position I in the middle;

[0049] Figure 5 A graph showing the results of a verification test provided according to one aspect of the present invention is shown;

[0050] Figure 6 A step diagram of a method for measuring oil quantity in a fuel injector according to one aspect of the present invention is shown.

[0051] Reference numerals:

[0052] 10-fuel injector oil quantity measurement structure; 100-injector tooling; 110-fuel injector; 200-voltage stabilizing filter module; 210-defogger; 211-oil inlet; 212-first chamber; 213-first cone; 214-connecting channel; 215-second chamber; 216-second cone; 220-straight pipe; 230-pressure stabilizing tank; 231-first opening; 232-second opening; 233-adapter; 240-throttling device; 241-throttling hole; 242-oil outlet; 300-cooling filter module; 311-plate heat exchanger; 312-filter; 400-medium metering module; 411-temperature sensor; 412-flow meter; 413-controller; 500-oil return module; 511-coil; 512-oil tank. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0054] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", "vertical" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0055] At the same time, it should be noted that the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0056] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, an integral connection, or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or the internal communication of two components, etc. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] Figure 1 This is a schematic diagram of the structure of the fuel injector oil quantity measurement structure 10 provided in this embodiment. Figure 1This embodiment provides a fuel injector oil quantity measurement structure 10, which includes a medium metering module 400, which is used to obtain the measured temperature and measured flow rate of the oil sprayed by the fuel injector 111, and obtain the average volume flow rate at the corrected temperature according to the measured temperature and the measured flow rate; and the medium metering module 400 is also used to obtain the flow coefficient corresponding to the average volume flow rate, and calculate the accurate flow rate sprayed by the fuel injector according to the average volume flow rate and the flow coefficient. The fuel injector oil quantity measurement structure fully considers the influence of temperature on flow measurement, and further corrects the flow rate through the flow coefficient after temperature compensation correction, so as to effectively improve the accuracy and reliability of the measured flow data.

[0058] The fuel injector oil quantity measuring structure 10 provided in this embodiment is further described below:

[0059] Please continue to refer to Figure 1 In this embodiment, the medium metering module 400 includes a temperature sensor 411, a flow meter 412 and a controller 413. The temperature sensor 411 and the flow meter 412 are both electrically connected to the controller 413. The temperature sensor 411 is used to obtain the temperature of the oil sprayed by the fuel injector, and the temperature obtained by the temperature sensor 411 is the measurement temperature; at the same time, the temperature sensor 411 also transmits a temperature signal representing the measurement temperature to the controller 413. The flow meter 412 is used to obtain the flow rate of the oil sprayed by the fuel injector 111, and the flow rate obtained by the flow meter 412 is the measurement flow rate; at the same time, the flow meter 412 also transmits a flow signal representing the measurement flow rate to the controller 413. The controller 413 is used to obtain the average volume flow rate at the corrected temperature according to the measurement temperature and the measurement flow rate, and calculates the accurate flow rate sprayed by the fuel injector according to the flow coefficient corresponding to the average volume flow rate and the average volume flow meter 412. Specifically, the operation process of the controller 413 will be introduced later.

[0060] Further, the temperature sensor 411 is arranged upstream of the flow meter 412. In other words, the liquid oil sprayed by the fuel injector 111 first passes through the temperature sensor 411 and then flows through the flow meter 412. Optionally, the temperature sensor 411 is a high-precision platinum resistance temperature sensor. Optionally, the flow meter 412 is a gear flow meter. The gear flow meter is of high precision, with a flow measurement range of 0.01 to 10L / min, a metering accuracy of ±0.3% of the actual measured value, and a repeatability accuracy of ±0.05%. It can monitor the oil flow rate flowing through the gear flow meter in real time. It can be understood that in some other embodiments, other types of temperature sensors 411 and flow meters 412 can also be used.

[0061] In this embodiment, the fuel injector oil quantity measurement structure 10 also includes a voltage stabilizing filter module 200, which can effectively reduce the impact of pressure fluctuations of the high-pressure medium on the flow rate, thereby improving the flow measurement accuracy. The voltage stabilizing filter module 200 has an oil inlet 211 and an oil outlet 242. The oil inlet 211 is used to receive the oil sprayed by the fuel injector 111, and the oil outlet 242 is connected to the medium metering module 400. In this way, the oil sprayed by the fuel injector 111 enters the medium metering module 400 after being processed by the voltage stabilizing filter module 200, so that more accurate flow data can be finally measured.

[0062] Figure 2 FIG. 2 shows a schematic cross-sectional structure diagram of the voltage stabilizing and filtering module 200 in the fuel injector oil quantity measuring structure 10 provided in this embodiment. Figure 1 and Figure 2 Specifically, the voltage stabilizing and filtering module 200 includes a demisting block 210, a straight pipe 220, a voltage stabilizing tube, and a throttling member 240 connected in sequence. The demisting block 210 has a passage for oil to flow, so that the oil sprayed by the fuel injector 111 is received through the passage. Accordingly, the demisting block 210 has an inlet for the oil to enter the demisting block 210, and the inlet serves as the oil inlet 211 of the voltage stabilizing and filtering module 200. Similarly, the throttling member 240 has a passage for oil to flow, so that the oil is led downstream through the passage. Accordingly, the throttling member 240 has an outlet for the oil to flow out, and the outlet serves as the oil outlet 242 of the voltage stabilizing and filtering module 200. The mist block 210 is used to collect the oil beam sprayed by the fuel injector 111; the branch pipe is used to reduce the pressure fluctuation of the oil flow; the pressure regulating tank 230 is used to store the oil and stabilize the pressure; the throttling member 240 has a throttling hole 241 connecting the pressure regulating tank 230 and the oil outlet 242, and the pulsating impact generated by continuous injection is suppressed through the throttling hole 241.

[0063] Furthermore, the fuel injector oil quantity measuring structure 10 also includes an injector tooling, which is mounted on the mist elimination block 210 and communicated with the oil inlet 211. When measuring the oil quantity of the fuel injector 111, the fuel injector 111 to be measured is mounted on the injector tooling, thereby realizing the connection between the fuel injector 111 and the mist elimination block 210. At the same time, the provision of the injector tooling helps to ensure the oil sealing, so that the measurement signal is accurate and effective.

[0064] Optionally, the fuel injector fixture and the mist dispelling block 210 are effectively fastened and connected by bolts, and a copper gasket is also provided at the connection point between the fuel injector and the mist dispelling block 210 to ensure effective sealing of the connection point.

[0065] Figure 3The internal structure diagram of the demisting block 210 in the fuel injector oil quantity measurement structure 10 provided in this embodiment is shown. Figure 1-Figure 3 The working principle of the mist dispelling block 210 is to form a pressure vessel with a certain shape and a certain volume according to different injection pressures and injection flows. In this embodiment, the mist dispelling block 210 includes a connecting channel 214 and a first chamber 212 and a second chamber 215 arranged on both sides of the connecting channel 214, and the connecting channel 214 connects the first chamber 212 and the second chamber 215. The side of the first chamber 212 away from the second chamber 215 forms an oil inlet 211, and the side of the second chamber 215 away from the first chamber 212 is connected to the straight pipe 220. The cross-sectional area of ​​the first chamber 212 is larger than the cross-sectional area of ​​the second chamber 215, and the cross-sectional area of ​​the second chamber 215 is larger than the cross-sectional connection of the connecting channel 214, and the end of the first chamber 212 communicating with the connecting channel 214 has a first conical surface 213, and the end of the second chamber 215 communicating with the connecting channel 214 has a second conical surface 216.

[0066] Specifically, the space of a certain shape and a certain volume in the demisting block 210 includes a first chamber 212, a connecting passage 214, and a second chamber 215. The first chamber 212 is located on the side where the demisting block 210 is connected to the injector tooling. The liquid oil sprayed by the fuel injector 111 first enters the first chamber 212, then enters the second chamber 215 through the connecting passage 214, and enters the straight pipe 220 after leaving the demisting block 210 from the second chamber 215. The first chamber 212, the second chamber 215, and the connecting passage 214 are all roughly cylindrical chambers, and the cross-sectional area of ​​the first chamber 212 is larger than that of the second chamber 215, and the cross-sectional area of ​​the second chamber 215 is larger than that of the connecting passage 214. In other words, the internal space of the demisting block 210 is roughly a structure with large ends and small in the middle.

[0067] At the same time, one end of the first chamber 212 connected to the communication channel 214 has a first conical surface 213, the cross-sectional area of ​​the first conical surface 213 decreases along the direction close to the communication channel 214, and the cross-sectional area of ​​the connection between the first conical surface 213 and the communication channel 214 is the same as the cross-sectional area of ​​the communication channel 214; one end of the second chamber 215 and the communication channel 214 has a second conical surface 216, the cross-sectional area of ​​the second conical surface 216 decreases along the direction close to the communication channel 214, and the cross-sectional area of ​​the connection between the second conical surface 216 and the communication channel 214 is the same as the cross-sectional area of ​​the communication channel 214. It has been verified by experiments that the space of this shape structure can effectively handle the collection of the fuel beam sprayed by the fuel injector 111.

[0068] Furthermore, the inner wall of the mist removal block 210 is treated with a strengthening process.

[0069] In this embodiment, the straight pipe 220 is connected to the mist dispelling block 210 by bolts, and the straight pipe 220 can effectively solve the pressure fluctuation of the oil in the pipeline. The straight pipe 220 is a tubular member with a certain length, which connects the mist dispelling block 210 and the pressure stabilizing tank 230. In order to ensure the effect of the straight pipe 220 in improving the pressure fluctuation, the length L, inner diameter d and wall thickness δ of the straight pipe 220 can be set. Specifically, since the length L, inner diameter d and wall thickness δ of the straight pipe 220 and the pressure fluctuation ΔP satisfy the following formula:

[0070] ΔP=ρv(L / t)=ρvc

[0071]

[0072] Among them, L is the length of the pressure channel, t is the time for the pressure wave to travel from the pressure source to the valve port, ΔP is the pressure fluctuation, ρ is the liquid density, v is the flow velocity of the liquid medium in the channel, c is the propagation velocity of the compressible liquid pressure wave, K is the liquid elastic modulus, E is the elastic modulus of the pipeline channel, δ is the wall thickness of the pipeline channel, and d is the diameter of the pipeline channel.

[0073] Therefore, the length L, the inner diameter d and the wall thickness δ of the straight tube 220 can be set according to the following method to reduce the pressure fluctuation ΔP.

[0074] 1. Extend the length of the pipeline:

[0075] For a certain medium, within a certain range of temperature and pressure changes, the longer the pipeline length, the longer it takes for a single pressure wave to propagate, that is, the longer the propagation period of the pressure wave.

[0076] 2. Methods for reducing the propagation speed of pressure waves: The elastic modulus of K liquid is related to the medium. The inner wall of the pipeline can be reduced within the allowable strength range, while the diameter of the pipeline can be increased.

[0077] The pressure stabilizing tank 230 is a pressure vessel with a certain volume, which serves as an oil storage container at the rear end of the straight pipe 220 to further stabilize the oil pressure and eliminate the influence of fluctuations. The pressure stabilizing tank 230 is connected to the straight pipe 220 by bolts, and a copper gasket is set at the connection to form an effective seal.

[0078] Figure 4 for Figure 2 The enlarged schematic diagram of the local structure at I in the middle. Please refer to Figure 1-Figure 4In this embodiment, the throttle 240 is installed on the pressure stabilizing tank 230, and the throttle 240 has a throttle hole 241 connected to the pressure stabilizing tank 230, and the pressure stabilizing tank 230 and the medium metering module 400 are connected through the throttle hole 241. Specifically, the upper end surface of the pressure stabilizing tank 230 is provided with a first opening 231 and a second opening 232, and the straight pipe 220 is fixedly connected to the first opening 231, so that the oil in the straight pipe 220 enters the pressure stabilizing tank 230 through the first opening 231. The throttle 240 is installed at the second opening 232, and the oil in the pressure stabilizing tank 230 enters the throttle 240 through the second opening 232 and flows out through the throttle hole 241. Optionally, an adapter 233 is provided at the second opening 232, and the throttle 240 is installed at the adapter 233.

[0079] Optionally, the aperture of the throttle hole 241 is 0.8 mm to 1.2 mm. Optionally, the aperture of the throttle hole 241 can be set to 0.8 mm, 1.0 mm or 1.2 mm. Further, in order to verify the effect of the throttle hole 241, a throttle hole 241 with an aperture of 1.0 mm is used as an example, and a throttle hole 241 with an aperture of 1.5 mm is used as a comparative example for experimental verification. Figure 5 The test results are shown, as Figure 5 As shown, curve 1 is the pressure pulsation curve in the pressure stabilizing tank 230 of the embodiment at a rail pressure of 1550 bar, and curve 2 is the pressure pulsation curve in the pressure stabilizing tank 230 of the comparative example at a rail pressure of 1550 bar. By comparison, it can be seen that the fluctuation range of curve 1 is smaller than that of curve 2. In addition, the embodiment is implemented at a rail pressure of 1600 bar to obtain curve 3. By comparing curve 1 and curve 3, it can be seen that the pressure pulsation curves are basically consistent, and no obvious fluctuation changes occur due to the increase in rail pressure. Therefore, it can be proved that the throttle hole 241 with the above aperture can effectively suppress the pulsation impact generated by continuous injection.

[0080] Please refer again Figure 1 In this embodiment, the fuel injector oil quantity measuring structure 10 also includes a cooling filter module 300, which is arranged between the voltage stabilizing filter module 200 and the medium metering module 400, so as to cool and filter the oil before the oil enters the medium metering module 400, thereby ensuring the cleanliness of the oil and the flow meter 412, which helps to ensure the measurement accuracy.

[0081] Specifically, the cooling and filtering module 300 includes a plate heat exchanger 311 and a filter 312. The plate heat exchanger 311 is connected to the throttling device 240, so as to cool the oil leaving the throttling device 240 to adjust the oil temperature and reduce the influence of temperature on the measurement accuracy to a certain extent. The filter 312 is arranged between the plate heat exchanger 311 and the temperature sensor 411, and the oil flowing through the system pipe system can be precisely filtered through the filter 312.

[0082] In this embodiment, the fuel injector oil quantity measurement structure 10 further includes an oil return module 500, which is arranged downstream of the medium metering module 400. Specifically, the oil return module 500 includes a coil 511 and an oil tank 512. The coil 511 is connected to the flow meter 412, and the coil 511 is used to form a back pressure in the pipeline flow channel and to a certain extent play a role in stabilizing the pressure of the system pipeline. The oil tank 512 is arranged at the tail end of the coil 511, which is used to receive the liquid oil that normally flows in and remains in the pipeline.

[0083] Figure 6 This is a step diagram of the fuel injector oil quantity measurement method provided in this embodiment. Please refer to Figure 1-Figure 6 The embodiment of the present invention further provides a fuel injector oil quantity measurement method, which is used to measure the flow rate of liquid oil sprayed by the fuel injector 111. Specifically, the controller 413 in the above-mentioned fuel injector oil quantity measurement structure 10 can execute the fuel injector oil quantity measurement method, thereby obtaining an accurate measurement value of the fuel injection quantity of the fuel injector 111. In other words, the fuel injector oil quantity measurement method can also be regarded as a specific operation process of the controller 413.

[0084] Controller 413 is used to display and calculate the oil quantity value. The oil quantity measurement system software interface is developed based on PLC and Labview software. PLC collects and controls the oil temperature and gear flowmeter 412 pulse signal data. Labview software programming algorithm converts and processes the data, thereby realizing the collection, measurement and calculation functions of the entire flowmeter 412 quantity system.

[0085] In this embodiment, the fuel injector oil quantity measurement method includes the following steps:

[0086] S01: Obtain the measured temperature and measured flow rate of the oil sprayed by the fuel injector 111.

[0087] The temperature sensor 411 performs temperature measurement to obtain the measured temperature, and the flow meter 412 performs flow measurement to obtain the measured flow.

[0088] S02: Obtain the average volume flow rate at the corrected temperature according to the measured temperature and the measured flow rate.

[0089] In order to eliminate the influence of oil temperature on density and thus ensure the measurement accuracy of flow rate, temperature correction is required to convert the measured flow rate into volume flow rate at the corrected temperature. Specifically, step S02 includes:

[0090] S21: Convert the measured flow rate into the volume flow rate at the corrected temperature.

[0091] The measured flow is the original volume flow. The controller 413 sets a metering period t. During this period, multiple measured flow signals Q are collected. T2 , and at the same time, the flow rate signal Q is obtained by the temperature sensor 411 T2 The corresponding measured temperature signal T2 is then used to convert the measured flow rate into the volume flow rate at the corrected temperature according to the following formula:

[0092]

[0093] Among them, Q T1 is the volume flow rate at the corrected temperature; Q T2 is the measured flow rate; T2 is the oil density at the measurement temperature; ρ T1 is the oil density at the corrected temperature.

[0094] Measuring flow signal Q T2 is an instantaneous signal. Accordingly, the volume flow rate Q at the corrected temperature calculated by the above conversion formula is T1 is also the instantaneous flow rate. Therefore, step S02 also includes:

[0095] S22: Calculate the average volume flow rate at the corrected temperature using the volume flow meter 412.

[0096] The average volume flow rate at the corrected temperature is calculated using the following formula:

[0097]

[0098] Among them, ΔQ T1 is the average volume flow rate; t is the duration corresponding to a metering cycle.

[0099] Optionally, in this embodiment, the correction temperature is 40°C.

[0100] S03: Obtain a flow coefficient corresponding to the average volume flow rate.

[0101] In order to further ensure the measurement accuracy, it is necessary to perform flow correction according to the flow coefficient. Specifically, the controller 413 stores a flow coefficient corresponding to the average volume flow. After the average volume flow is calculated, the flow coefficient corresponding to the average volume flow stored in the controller 413 can be called to perform flow correction. Therefore, the fuel injector oil quantity measurement method can also include a step S31 of calculating the flow coefficient, and the step S31 includes:

[0102] Divide the flow interval and determine the flow coefficient of each flow curve separately.

[0103] When dividing the flow rate interval, it can be divided into the following intervals: (0ml / min, 100ml / min), [100ml / min, 500ml / min), [500ml / min, 1000ml / min), [1000ml / min, 2000ml / min), [2000ml / min, 3000ml / min) and [3000ml / min, 4000ml / min).

[0104] After the flow interval is divided, for each flow interval, the volume flow rate within a metering cycle and multiple sets of data of the average volume flow rate at the corrected temperature are obtained by the weighing method. The volume flow rate Q T1称重 and the average volume flow rate ΔQ at the corrected temperature T1 Satisfies the following formula:

[0105] Q T1称重 =aΔQ T1 +b;

[0106] Among them, a and b are flow coefficients.

[0107] The specific values ​​of flow coefficients a and b are obtained by fitting multiple sets of data.

[0108] Specifically, the volume flow rate Q obtained by weighing method T1称重 , can be calculated in the following way: the oil mass m under the same metering cycle t is obtained by weighing according to the gravimetric method, and the oil volume flow rate Q under the metering cycle is obtained according to the following formula T1称重 :

[0109]

[0110] It should be noted that the specific number of intervals divided here and the flow range corresponding to each interval are not limited. It can be understood that in other embodiments, other numbers of intervals and the flow range corresponding to each interval can also be set according to needs. The more flow intervals there are and the smaller the flow range corresponding to each interval, the more accurate the data for flow correction based on the flow coefficient will be.

[0111] Step S03 includes: determining the flow interval to which the average volume flow belongs, and using the flow coefficient corresponding to the flow interval as the flow coefficient corresponding to the average volume flow. For example, if the average volume flow calculated is 1500ml / min, the flow interval of the average volume flow is [1000ml / min, 2000ml / min), then the flow coefficient of the flow interval [1000ml / min, 2000ml / min) is used as the flow coefficient for flow correction.

[0112] S04: Calculate the exact flow rate of the fuel injector according to the average volume flow rate and the flow coefficient. Calculate the exact flow rate of the fuel injector 111 according to the following formula:

[0113] Q′=aΔQ T1 +b

[0114] Where Q′ is the accurate flow rate; ΔQ T1 is the average volume flow rate; a and b are flow coefficients.

[0115] The calculated accurate flow rate sprayed by the fuel injector 111 is the final flow rate obtained by the fuel injector oil quantity measurement method provided in the embodiment of the present invention.

[0116] The fuel injector oil quantity measurement method and structure provided by the embodiment of the present invention takes into account the influence of pressure fluctuation of high-pressure medium on flow, the influence of test medium viscosity of high hydraulic system on ambient temperature, and the influence of different flow intervals on flow coefficient, and adopts a method of pressure stabilization and wave elimination device, temperature compensation correction and flow coefficient of different intervals for distinguishing and calculating flow measurement, so as to obtain more accurate flow measurement data. At the same time, the fuel injector oil quantity measurement method and structure also have the advantages of high reliability, simple measurement and short time consumption, which effectively reduces the technical risks that may occur in the fuel system, thereby improving efficiency, and can be applied to the research and development of fuel injection system products (such as methanol injection system) and product performance verification.

[0117] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technology in the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for measuring the amount of oil in a fuel injector, characterized in that: The fuel injector oil quantity measurement method comprises: Obtain the measured temperature and flow rate of the oil sprayed by the fuel injector; Obtaining an average volume flow rate at a corrected temperature according to the measured temperature and the measured flow rate; Obtaining a flow coefficient corresponding to the average volume flow rate; The accurate flow rate sprayed by the fuel injector is calculated according to the average volume flow rate and the flow coefficient.

2. The fuel injector oil quantity measurement method according to claim 1, characterized in that: The step of obtaining the average volume flow rate at the corrected temperature according to the measured temperature and the measured flow rate comprises: The measured flow is converted into the volume flow at the corrected temperature, and the conversion formula is: Among them, Q T1 is the volume flow rate at the corrected temperature; Q T2 is the measured flow rate; ρ T2 is the oil density at the measuring temperature; ρ T1 is the oil density at the corrected temperature; The average volume flow rate at the corrected temperature is calculated based on the volume flow rate, and the calculation formula is: Among them, ΔQ T1 is the average volume flow rate; t is the duration corresponding to a metering cycle.

3. The fuel injector oil quantity measurement method according to claim 1, characterized in that: Before the step of obtaining the flow coefficient corresponding to the average volume flow, the fuel injector oil quantity measurement method further includes: Divide the flow interval and calculate the flow coefficient of each flow interval respectively; The step of obtaining a flow coefficient corresponding to the average volume flow rate comprises: The flow interval to which the average volume flow belongs is determined, and the flow coefficient corresponding to the flow interval is used as the flow coefficient corresponding to the average volume flow.

4. The fuel injector oil quantity measurement method according to claim 3, characterized in that: The steps of dividing the flow intervals and respectively determining the flow coefficient of each flow interval include: The flow rate interval is divided into the following intervals: (0 ml / min, 100 ml / min), [100 ml / min, 500 ml / min), [500 ml / min, 1000 ml / min), [1000 ml / min, 2000 ml / min), [2000 ml / min, 3000 ml / min) and [3000 ml / min, 4000 ml / min); For each flow interval, the weighing method is used to obtain multiple sets of data on the volume flow rate within a metering cycle and the average volume flow rate at the corrected temperature. The volume flow rate Q obtained by the weighing method is T1称重 and the average volume flow rate ΔQ at the corrected temperature T1 Satisfies the following formula: Q T1称重 =aΔQ T1 +b; Among them, a and b are flow coefficients.

5. The fuel injector oil quantity measurement method according to claim 1, characterized in that: The calculation formula for obtaining the accurate flow rate sprayed by the fuel injector according to the average volume flow rate and the flow coefficient is: Q′=aΔQ T1 +b Where Q′ is the accurate flow rate; ΔQ T1 is the average volume flow rate; a and b are flow coefficients.

6. The fuel injector oil quantity measurement method according to claim 1, characterized in that: The corrected temperature is 40°C.

7. A fuel injector oil quantity measurement structure, characterized in that: The fuel injector oil quantity measuring structure comprises: A medium metering module, the medium metering module is used to obtain the measured temperature and measured flow rate of the oil sprayed by the fuel injector, and obtain the average volume flow rate at the corrected temperature based on the measured temperature and the measured flow rate; and the medium metering module is also used to obtain the flow coefficient corresponding to the average volume flow rate, and calculate the accurate flow rate sprayed by the fuel injector based on the average volume flow rate and the flow coefficient.

8. The fuel injector oil quantity measuring structure according to claim 7, characterized in that: The medium metering module includes a temperature sensor, a flow meter and a controller, wherein the temperature sensor and the flow meter are both electrically connected to the controller; the temperature sensor is used to obtain the temperature of the oil sprayed by the fuel injector and transmit a temperature signal representing the temperature to the controller; the flow meter is used to obtain the flow rate of the oil sprayed by the fuel injector and transmit a measured flow rate representing the flow rate to the controller; The controller is used to obtain an average volume flow rate at a corrected temperature according to the measured temperature and the measured flow rate, and to calculate an accurate flow rate sprayed by the fuel injector according to a flow coefficient corresponding to the average volume flow rate and the average volume flow rate.

9. The fuel injector oil quantity measuring structure according to claim 8, characterized in that: The temperature sensor is disposed upstream of the flow meter.

10. The fuel injector oil quantity measuring structure according to claim 7, characterized in that: The fuel injector oil quantity measurement structure further comprises a voltage stabilizing filter module, the voltage stabilizing filter module having an oil inlet and an oil outlet, the oil inlet is used to receive the oil sprayed by the fuel injector, and the oil outlet is connected to the medium metering module; The voltage stabilizing and filtering module includes a demisting block, a straight pipe, a pressure stabilizing tank and a throttling device connected in sequence; the oil inlet is the inlet of the demisting block, and the oil outlet is the outlet of the throttling device; the demisting block is used to collect the oil beam sprayed by the fuel injector; the straight pipe is used to weaken the pressure fluctuation of the oil flow; the pressure stabilizing tank is used to store the oil and stabilize the pressure; the throttling device has a throttling hole connecting the pressure stabilizing tank and the oil outlet, and the throttling hole is used to suppress the pulsation impact caused by continuous injection.

11. The fuel injector oil quantity measuring structure according to claim 10, characterized in that: The demisting block includes a communication channel and a first chamber and a second chamber arranged on both sides of the communication channel, and the communication channel connects the first chamber and the second chamber; the first chamber forms the oil inlet on a side away from the second chamber, and the second chamber is connected to the straight pipe on a side away from the first chamber; The cross-sectional area of ​​the first chamber is larger than that of the second chamber, the cross-sectional area of ​​the second chamber is larger than that of the connecting passage, and one end of the first chamber connected to the connecting passage has a first conical surface, and one end of the second chamber connected to the connecting passage has a second conical surface.

12. The fuel injector oil quantity measuring structure according to claim 10, characterized in that: The aperture of the throttling hole is 0.8 mm to 1.2 mm.

Images