Evaluation device, evaluation system, evaluation method, and program

Abstract

This invention provides a simple method for evaluating individual differences in the injection response delay time of fuel injectors that supply fuel to an engine. [Solution] The measuring device is a measuring device for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, and comprises means for acquiring a measured value of a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, means for measuring the response time from the time the open command is issued until the measured value changes, and means for evaluating individual differences in the injection response delay time of the fuel injector to be evaluated by calculating the difference between a predetermined first response time that serves as a reference and a second response time measured for the fuel injector to be evaluated.

Description

Technical Field

[0001] The present disclosure relates to an evaluation device, an evaluation system, an evaluation method, and a program for a fuel injection device.

Background Art

[0002] In an engine (e.g., a diesel engine) that injects fuel into a cylinder to cause self-ignition, it is necessary to precisely control the timing at which fuel is actually injected from the fuel injection valve from the viewpoints of engine performance, vibration, emissions, durability, etc. Also, in a general fuel injection valve, there is a response delay from when an energization signal for injection is applied until the valve body actually lifts and injection starts. This response delay time has individual differences due to tolerances of each part of the injection valve. Therefore, in order to precisely control the timing of fuel injection, it is necessary to grasp this individual difference. For example, in Patent Document 1, before assembling a fuel injection valve into an internal combustion engine, the fuel injection valve is preliminarily classified into one of a plurality of grades regarding injection response delay characteristics, and based on the classified grade, a reference fuel injection timing is corrected to control the injection timing in a spark ignition type multi-cylinder internal combustion engine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, a method for evaluating the individual differences in the injection response delay time of a fuel injection valve is required. For example, in order to grasp the injection response delay time of a fuel injection valve, a method of measuring the flow rate per unit time (injection rate) of fuel injected from each individual of the fuel injection valve is provided. However, this measurement requires a dedicated measuring device, which complicates the equipment configuration and increases the equipment investment cost.

[0005] This disclosure provides an evaluation device, an evaluation system, an evaluation method, and a program that can solve the above-mentioned problems. [Means for solving the problem]

[0006] The evaluation device of the present disclosure is a measuring device for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, and comprises: means for acquiring a measured value of a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector; means for measuring the response time from the time the open command is issued until the measured value changes; and means for evaluating individual differences in the injection response delay time of the fuel injector to be evaluated by calculating the difference between a predetermined first response time that serves as a reference and a second response time measured for the fuel injector to be evaluated.

[0007] The evaluation system of this disclosure comprises a fuel supply system equipped with a fuel injector for injecting fuel, a control device for controlling the fuel injector, a sensor for detecting a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, and the evaluation device according to claim 1 or claim 2.

[0008] The evaluation method of the present disclosure is an evaluation method for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, and comprises the steps of: acquiring a measured value of a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector; measuring the response time from the time the open command is issued until the measured value changes; and evaluating individual differences in the injection response delay time of the fuel injector to be evaluated by calculating the difference between a predetermined first response time that serves as a reference and a second response time measured for the fuel injector to be evaluated.

[0009] The program of this disclosure causes a computer to perform a process for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, the process comprising: acquiring a measured value from a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector; measuring the response time from the time the open command is issued until the measured value changes; and calculating the difference between a predetermined first response time that serves as a reference and a second response time measured for the fuel injector to be evaluated, thereby evaluating individual differences in the injection response delay time of the fuel injector to be evaluated. [Effects of the Invention]

[0010] According to the evaluation device, evaluation system, evaluation method, and program described above, individual differences in the injection response delay time of fuel injectors can be easily evaluated. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of the evaluation system according to the first embodiment. [Figure 2] This figure illustrates a method for evaluating the injection response delay time according to the first embodiment. [Figure 3A] This is a first flowchart showing an example of the evaluation process for the injection response delay time according to the first embodiment. [Figure 3B] This is a second flowchart showing an example of the evaluation process for the injection response delay time according to the first embodiment. [Figure 4] This is a schematic diagram of the evaluation system according to the second embodiment. [Figure 5] This is a schematic diagram of the evaluation system according to the third embodiment. [Figure 6] This figure illustrates a method for evaluating the injection response delay time according to the third embodiment. [Figure 7] This is a schematic diagram showing an example of the hardware configuration of the evaluation system according to each embodiment. [Modes for carrying out the invention]

[0012] <First Embodiment> The method for evaluating individual differences in the injection response delay time of fuel injectors according to this embodiment will be described below with reference to Figures 1 to 3. Figure 1 is a schematic diagram of the evaluation system according to the first embodiment. The evaluation system 100 includes a fuel supply system 10, a measuring device 20 for measuring the injection response delay time of the fuel injector 4, a control device 30 for controlling the fuel supply system 10, and a pressure sensor 6 for detecting changes in the state of the fuel supply system 10. The fuel supply system 10 includes a fuel tank 1, a high-pressure pump 2, an accumulator 3, a fuel injector 4, and piping 5 connecting them. The fuel in the fuel tank 1 is pressurized by the high-pressure pump 2, and the high-pressure fuel is sent to the accumulator 3 through the piping 5. The high-pressure fuel stored in the accumulator 3 is injected from the fuel injector 4. The control device 30 controls the opening and closing of the fuel injector 4. When the control device 30 opens the fuel injector 4, fuel is injected. In engines that perform diffusion combustion, such as diesel engines, or engines that perform diffusion combustion in addition to some premixed combustion, combustion occurs through autoignition when a mixture of fuel and air in a certain ratio reaches a certain temperature. Controlling such engines requires high-precision control of the timing of actual fuel injection from the fuel injector, compared to engines that perform complete premixed combustion or forced ignition. There is a certain response delay between the time the control device 30 issues an open command to the fuel injector 4 and the time when fuel is actually injected, but there are individual differences in the fuel injector 4, and this response delay time also varies from one fuel injector 4 to another. Unless the open command to the fuel injector 4 is issued according to the injection response delay of each fuel injector 4, which has individual differences, the desired combustion control cannot be achieved. Therefore, in the evaluation system 100 of this embodiment, a pressure sensor 6 is installed upstream of the fuel supply system 10 of the fuel injector 4 before shipment, and the injection response delay time of the fuel injector 4 is evaluated by analyzing the measurement results of the pressure sensor 6 with the measuring device 20. The measuring device 20 calculates the difference between the measured injection response delay time and a reference injection response delay time. For example, the reference injection response delay time may be set to the average value of the injection response delay times of several fuel injectors 4 measured using the evaluation system 100. This time difference serves as a compensation value to compensate for individual differences in injection response delay time.At the time of shipment, the fuel injector 4 is removed from the evaluation system 100 and shipped with the compensation value linked to it. After shipment, the fuel injector 4 is installed in the engine's fuel supply system, and the compensation value linked to the fuel injector 4 is set in the engine's control unit.

[0013] The pressure sensor 6 is installed between the accumulator 3 and the fuel injector 4 in the piping 5 and measures the pressure inside the piping 5. As will be explained next with reference to Figure 2, in this embodiment, the injection response delay time is measured by focusing on the time-series pressure change caused by the injection of fuel from the fuel injector 4. This pressure change propagates in the opposite direction of the fuel flow, from the fuel injector 4 towards the accumulator 3. In order to accurately evaluate individual differences in the fuel injector 4, it is desirable that the pressure sensor 6 be installed as close to the fuel injector 4 as possible.

[0014] The measuring device 20 comprises an acquisition unit 21, an evaluation unit 22, an output unit 23, and a storage unit 24. The acquisition unit 21 acquires the pressure measured by the pressure sensor 6 and records the acquired pressure and its acquisition time in the storage unit 24. The evaluation unit 22 measures the injection response delay time of the fuel injector 4 and calculates a compensation value to compensate for individual differences in the injection response delay time. The output unit 23 outputs a compensation value to compensate for individual differences in the injection response delay time for each fuel injector 4. The storage unit 24 stores the time-series pressure measured by the pressure sensor 6.

[0015] Figure 2 illustrates the method for evaluating the injection response delay time according to the first embodiment. Figures 2(a) to 2(d) schematically represent the time-series data of the energization waveform of the fuel injector 4, the fuel injection rate injected from the fuel injector 4, the internal pressure of the fuel injector 4, and the pressure detected by the pressure sensor 6, respectively. The same position on the horizontal axis in Figures 2(a) to 2(d) represents the same time.

[0016] The vertical axis of Fig. 2(a) represents current, and the horizontal axis represents time. The current is the current of the opening command (energization signal) output by the control device 30 to the fuel injection valve 4. Graph 200 shows the transition of the energization signal. When the current value of the command signal exceeds a predetermined value, it becomes an opening command to the fuel injection valve 4. In the case of Fig. 2(a), an opening command to the fuel injection valve 4 is output at time t0.

[0017] The vertical axis of Fig. 2(b) represents injection rate, and the horizontal axis represents time. Graphs 201 to 203 show the transition of the injection rate. Graph 201 shows the transition of the injection rate of a certain fuel injection valve 4 (referred to as individual A). Graph 202 shows the transition of the injection rate of a fuel injection valve 4 different from individual A (referred to as individual B). Graph 203 shows the transition of the injection rate of a fuel injection valve 4 different from individual A and individual B (referred to as individual C). These graphs can be obtained, for example, by measuring the injection rate with dedicated equipment. The injection rate of individual A exceeds 0 at time t1. Since the fuel injection command was output at time t0, the injection response delay time of individual A is t1 - t0. The injection rate of individual B exceeds 0 at time t2. The injection response delay time of individual B is t2 - t0. The injection rate of individual C exceeds 0 at time t3. The injection response delay time of individual C is t3 - t0.

[0018] The vertical axis of Fig. 2(c) represents the pressure in the fuel injection valve 4, and the horizontal axis represents time. Graphs 204 to 206 show the transition of the pressure of individuals A to C, respectively. These graphs can be obtained, for example, by providing a pressure sensor in the fuel injection valve 4 and measuring the pressure. When an energization signal is applied to the fuel injection valve 4 and the valve body lifts to start injection, high-pressure fuel is discharged, causing the pressure inside the fuel injection valve 4 to decrease, and this pressure decrease propagates upstream in the fuel supply system 10. As shown in Graph 204, the pressure of individual A starts to decrease at time t1. Similarly, referring to Graphs 205 and 206, the pressure decreases of individuals B and C start at times t2 and t3, respectively. That is, the response delays of fuel injection of individuals A to C can also be measured by monitoring the pressure fluctuations (decreases) of individuals A to C.

[0019] The vertical axis of Fig. 2(d) represents the pressure measured by the pressure sensor 6, and the horizontal axis represents time. Graphs 207 to 209 show the transition of the pressure measured by the pressure sensor 6 installed on the upstream side of individuals A to C, respectively. The delay time from the application of the energization signal to the fuel injection valve 4 until the pressure sensor 6 detects a pressure drop is the sum of the injection response delay time and the time for the pressure drop generated in the fuel injection valve 4 to propagate to the pressure sensor 6. The time for the pressure drop generated in the fuel injection valve 4 to propagate to the pressure sensor 6 depends on the distance in the fuel supply system 10 from the injection hole of the fuel injection valve 4 to the pressure sensor 6 and the speed of sound in the fuel. Here, since the pressure sensor 6 is installed at the same position for any of individuals A to C, the time for the pressure drop generated in each of individuals A to C to propagate to the pressure sensor 6 is the same for individuals A to C. Therefore, there is a high correlation between the time from the application of the energization signal to the fuel injection valve 4 until the pressure sensor 6 detects a pressure drop and the injection response delay time, and the time difference from when the energization signal is output to individuals A to C until the pressure sensor 6 detects a pressure drop is the individual difference in the injection response delay time of individuals A to C.

[0020] By comparing the time from the application of the energization signal to the fuel injection valve 4 until the pressure sensor 6 detects a pressure drop with a reference fuel injection valve 4 for the fuel injection valve 4 to be evaluated, the time difference (individual difference) from the reference injection response delay time can be calculated with the same accuracy as when measuring the flow rate per unit time (injection rate) of the fuel injected from each individual of the fuel injection valve 4 using a dedicated measuring device. Also, by compensating the injection timing for the reference fuel injection valve 4 with the calculated time difference, fuel injection can be realized at a timing corresponding to the injection response delay time of each individual.

[0021] (Operation) Fig. 3A is a first flowchart showing an example of the evaluation process of the injection response delay time according to the first embodiment. The acquisition unit 21 acquires time-series pressure measurements of one or more reference fuel injectors 4 (for example, individual A or multiple fuel injectors 4) (step S1). When an energizing signal is applied from the control device 30 to the fuel injector 4, the acquisition unit 21 acquires time-series pressure measurements measured by the pressure sensor 6 and records them in the storage unit 24. Next, the acquisition unit 21 acquires time-series pressure measurements of the fuel injector 4 to be evaluated (for example, individual B or individual C) (step S2). The acquisition unit 21 acquires time-series pressure measurements measured by the pressure sensor 6 when an energizing signal is applied to the fuel injector 4 from the control device 30, and records them in the storage unit 24. Next, the evaluation unit 22 calculates a compensation value for the injection response delay time (step S3). The evaluation unit 22 reads the time-series pressure measurement values ​​of a reference fuel injector 4 from the storage unit 24 and calculates the time from when the energizing signal is applied until the pressure drop is measured. If there are multiple reference fuel injectors 4, the evaluation unit 22 calculates the average value (median or mode) of the time from when the energizing signal is applied until the pressure drop is measured for the multiple fuel injectors 4. This time is denoted as time T1. The evaluation unit 22 also reads the time-series pressure measurement values ​​of the fuel injector 4 under evaluation from the storage unit 24 and calculates the time from when the energizing signal is applied until the pressure drop is measured. This time is denoted as time T2. The evaluation unit 22 calculates the difference between time T2 and time T1. This time difference is the compensation value for the injection response delay time. Next, the output unit 23 outputs the compensation value to a display device or the like (step S4). The shipping engineer sets the outputted compensation value in the control device of the engine in which the fuel injector 4 to be evaluated will be installed after shipment. For example, the control device of this engine is designed and implemented to apply an energizing signal to the fuel injector 4 in its initial state, taking into account a reference injection response delay time T1. If time T2 > time T1, the engineer sets the control device to apply the energizing signal to the fuel injector 4 earlier by the amount of the compensation value (time T2 - time T1). This allows the fuel injector 4 with an injection response delay time T2 to inject fuel at the desired timing. Note that the setting of the compensation value in the control device may be configured to be done automatically.

[0022] Figure 3A illustrates the processing flow in conjunction with the explanation in Figure 2. Another processing flow involves pre-measuring the injection response delay time (more precisely, the time from the application of the energization signal to the detection of a pressure drop) of multiple fuel injectors 4 using the evaluation system 100, setting the average value of these values ​​as the reference injection response delay time in the measurement device 20, and then measuring the injection response delay time of the fuel injector 4 to be evaluated using the evaluation system 100. An example of a specific process is shown in Figure 3B. Figure 3B is a second flowchart showing an example of the injection response delay time evaluation process according to the first embodiment. Processes similar to those in Figure 3A are denoted by the same reference numerals and their explanations are omitted. As a prerequisite, it is assumed that the time from when an energizing signal is applied to multiple fuel injectors 4 until a pressure drop is measured is measured in advance, and the average value of these measurements is registered in the storage unit 24 as a reference injection response delay time. First, the acquisition unit 21 acquires a reference injection response delay time from the storage unit 24 (step S1'). Next, the acquisition unit 21 acquires the time-series pressure measurement values ​​of the fuel injector 4 to be evaluated (step S2). Next, the evaluation unit 22 calculates a compensation value for the injection response delay time (step S3'). The reference injection response delay time acquired in step S1' is defined as time T1. The evaluation unit 22 reads the time-series pressure measurement values ​​of the fuel injector 4 to be evaluated from the storage unit 24 and calculates the time from when the energization signal is applied until the pressure drop is measured. This time is defined as time T2. The evaluation unit 22 calculates the difference between time T2 and time T1. This time difference is the compensation value for the injection response delay time. Next, the output unit 23 outputs the compensation value to a display device or the like (step S4). Note that in Figure 3A, the processing order of steps S1 and S2 may be reversed. Similarly, in Figure 3B, the processing order of steps S1' and S2 may be reversed.

[0023] (effect) As described above, in this embodiment, when fuel injection starts, a pressure drop propagating through the fuel supply system 10 starting from the fuel injector 4 is detected by a pressure sensor 6 installed upstream of the fuel injector 4. The injection response delay time of each individual unit is determined and compensated for based on the time from the application of the energization signal to the fuel injector 4 to the detection of the pressure drop by the pressure sensor 6. As a result, when determining the injection response delay time of each individual unit during the factory operation of the fuel injector 4, it is possible to evaluate the individual differences in injection response delay time with a simpler equipment configuration and with the same level of accuracy as when measuring the flow rate (injection rate) of fuel injected per unit time from each unit using a dedicated measuring device.

[0024] In the above explanation, the compensation value was set to be the time difference between the average time T1 from the application of the energizing signal to the detection of a pressure drop measured for multiple reference fuel injectors 4 and the time T2 from the application of the energizing signal to the detection of a pressure drop measured for the fuel injector 4 under evaluation. However, by utilizing the fact that the time it takes for the pressure drop to propagate to the pressure sensor 6 depends on distance and the speed of sound, the time it takes for the pressure drop to propagate from the fuel injector 4 to the pressure sensor 6 can be calculated (length within the fuel supply system 10 from the fuel injector 4 to the pressure sensor 6 ÷ speed of sound), and the injection response delay time of the fuel injector 4 under evaluation can be calculated by subtracting this time from time T2. The compensation value can be obtained by calculating the injection response delay time for each individual and calculating the difference with the injection response delay time of the reference fuel injector 4 calculated in the same manner.

[0025] <Second Embodiment> Hereinafter, an evaluation system 100a according to a second embodiment of the present invention will be described with reference to Figure 4. Figure 4 is a schematic configuration diagram of the evaluation system according to the second embodiment. The evaluation system 100a includes a strain gauge 7 for detecting changes in the surface condition of the fuel supply system 10, instead of a pressure sensor 6. The other configurations are the same as in the first embodiment. In the evaluation system 100a of the second embodiment, the strain gauge 7 is installed upstream of the fuel injector 4 in the fuel supply system 10 before shipment, and the injection response delay time of the fuel injector 4 is evaluated by analyzing the measurement results of the strain gauge 7 with a measuring device 20.

[0026] The strain gauge 7 is installed on the surface of the piping 5 between the accumulator 3 and the fuel injector 4. For the reasons described in the first embodiment, it is desirable that the strain gauge 7 be installed as close to the fuel injector 4 as possible.

[0027] As described in the first embodiment, when fuel injection starts, a pressure drop propagates through the inside of the fuel supply system 10, starting from the fuel injector 4. In the second embodiment, a strain gauge 7 attached to the surface of the fuel supply system 10 is used to detect changes in the amount of strain in the components (piping 5, etc.) that make up the fuel supply system 10 due to the pressure drop inside the fuel supply system 10. The time from the application of the energizing signal to the measurement of the change in the amount of strain due to the pressure drop is considered as the sum of the injection response delay time and the pressure drop propagation time. The difference between the time T3 measured for the reference fuel injector 4 and the time T4 measured for the fuel injector 4 under evaluation is evaluated as the individual difference in injection response delay time.

[0028] (operation) The process for evaluating individual differences in the injection response delay time of fuel injectors in the second embodiment is the same as the process described in the first embodiment with reference to Figure 3, except that the measurement target is changed from pressure drop to strain change. That is, the acquisition unit 21 acquires the time-series strain measurement values ​​of one or more reference fuel injectors 4 (for example, individual A) and records them in the storage unit 24 (corresponding to step S1 in Figure 3A). Alternatively, the storage unit 24 has registered a reference injection response delay time calculated based on the time-series strain measured for multiple fuel injectors 4 (more precisely, the time from the application of the energizing signal until the first strain change exceeding a predetermined value is measured), and the acquisition unit 21 reads and acquires this reference injection response delay time from the storage unit 24 (corresponding to step S1' in Figure 3B). Next, the acquisition unit 21 acquires the time-series strain measurement values ​​of the fuel injector 4 to be evaluated (for example, individual B, etc.) and records them in the storage unit 24 (corresponding to step S2 in Figures 3A and 3B). Next, the evaluation unit 22 calculates a compensation value for the injection response delay time (corresponding to step S3 in Figure 3A and step S3' in Figure 3B). The evaluation unit 22 reads the time-series strain measurement values ​​of the reference fuel injector 4 from the storage unit 24 and calculates the time T3 from when the energizing signal is applied until the first strain change exceeding a predetermined value is measured (step S3 in Figure 3A). Alternatively, the evaluation unit 22 sets the time T3 to a reference injection response delay time previously registered in the storage unit 24 (step S3' in Figure 3B). The evaluation unit 22 also reads the time-series strain measurement values ​​of the fuel injector 4 under evaluation from the storage unit 24 and calculates the time T4 from when the energizing signal is applied until the first strain change exceeding a predetermined value is measured. The evaluation unit 22 calculates the difference between time T4 and time T3 as the compensation value for the injection response delay time. Next, the output unit 23 outputs the compensation value to a display device or the like (corresponding to step S4 in Figures 3A and 3B). The output compensation value is set in the control device of the engine on which the fuel injection valve 4 to be evaluated is installed.

[0029] (effect) According to the second embodiment, by attaching strain gauges 7 to the surface of the components of the fuel supply system 10, the injection response delay time of each individual fuel injector can be evaluated more easily than when pressure sensors 6 are installed. In the second embodiment as well, the injection response delay time of the fuel injector 4 to be evaluated can be calculated by utilizing the fact that the time it takes for the pressure drop to propagate to the attachment position of the strain gauge 7 depends on the distance and the speed of sound. A compensation value can then be calculated by calculating the difference between this value and the injection response delay time of one or more reference fuel injectors 4 (or the average value of the injection response delay times of the fuel injectors 4 in the case of multiple fuel injectors) calculated in the same manner.

[0030] <Third Embodiment> Hereinafter, an evaluation system 100b according to a third embodiment of the present invention will be described with reference to Figures 5 and 6. Figure 5 is a schematic diagram of the evaluation system according to the third embodiment. The evaluation system 100b is equipped with a vibration sensor 8 instead of the pressure sensor 6 of the first embodiment. The other configurations are the same as those of the first embodiment. In the evaluation system 100b of the third embodiment, the vibration sensor 8 is installed near the fuel injector 4 of the fuel supply system 10 before shipment, and the injection response delay time of the fuel injector 4 is evaluated by analyzing the measurement results of the vibration sensor 8 with a measuring device 20.

[0031] The vibration sensor 8 is installed near the fuel injector 4. Unlike the first and second embodiments, which detect a pressure drop inside the fuel supply system 10 due to fuel injection, the vibration sensor 8 measures the rise of vibration caused by the valve body colliding with other parts (stoppers) inside the fuel injector 4 when the fuel injector 4 opens. The vibration sensor 8 is installed, for example, near the range of motion of the valve body of the fuel injector 4 body so that this vibration can be detected well.

[0032] Figure 6 illustrates a method for measuring the injection response delay time according to the third embodiment. Figures 6(a) to 6(c) schematically represent the time-series data of the energization waveform of the fuel injector 4, the fuel injection rate of the fuel injector 4, and the acceleration due to vibration of the fuel injector 4, respectively. The same position on the horizontal axis in Figures 6(a) to 6(c) represents the same time.

[0033] In Figure 6(a), the vertical axis represents the current of the energizing signal, and the horizontal axis represents time. Graph 600 shows the progression of the energizing signal. In Figure 6(a), an open command is applied to the fuel injection valve 4 at time t0.

[0034] In Figure 6(b), the vertical axis represents the injection rate and the horizontal axis represents time. Graph 601 shows the change in the injection rate. The injection rate of fuel injector 4 exceeds 0 at time t1. Since the fuel injection command is output at time t0, the injection response delay time of fuel injector 4 is t1-t0.

[0035] In Figure 6(c), the vertical axis represents the acceleration measured by the vibration sensor 8, and the horizontal axis represents time. Graph 602 shows the change in acceleration measured by the vibration sensor 8 installed on the fuel injector 4. The time from the application of the energizing signal to the fuel injector 4 to the detection of the vibration rise by the vibration sensor 8 is t2-t0. Since the rise in vibration measured by the vibration sensor 8 is thought to be associated with the opening of the control valve inside the fuel injector 4, it is considered that there is a correlation between the rise in the injection rate in Figure 6(b) and the rise in vibration in Figure 6(c). In other words, it is considered that there is a certain relationship between t2-t0 and t1-t0.

[0036] Therefore, by comparing the time from the application of an energizing signal to the fuel injector 4 to the detection of vibration by the vibration sensor 8 with that of the fuel injector 4 under evaluation and a reference fuel injector 4, the time difference in the injection response delay time of each individual fuel injector 4 can be calculated. Furthermore, by compensating the injection timing relative to the reference fuel injector 4 with the calculated time difference, fuel injection can be achieved at a timing corresponding to the injection response delay time of each individual.

[0037] (operation) The process for evaluating individual differences in the injection response delay time of fuel injectors in the third embodiment is the same as the process described in the first embodiment with reference to Figure 3, except that the measurement target is changed from pressure drop to vibration acceleration. That is, the acquisition unit 21 acquires the time-series acceleration measurement value of a reference fuel injector 4 and records it in the storage unit 24 (corresponding to step S1 in Figure 3A). Alternatively, the storage unit 24 has a reference injection response delay time (more precisely, the time from when the energizing signal is applied until the first rise in acceleration is measured) that has been calculated in advance based on time-series acceleration measurement values ​​measured for multiple fuel injectors 4, and the acquisition unit 21 reads and acquires this reference injection response delay time from the storage unit 24 (corresponding to step S1' in Figure 3B). Next, the acquisition unit 21 acquires the time-series acceleration measurement value of the fuel injector 4 to be evaluated and records it in the storage unit 24 (corresponding to step S2 in Figures 3A and 3B). Next, the evaluation unit 22 calculates a compensation value for the injection response delay time (corresponding to step S3 in Figure 3A and step S3' in Figure 3B). The evaluation unit 22 reads the time-series acceleration measurement values ​​of a reference fuel injector 4 from the storage unit 24 and calculates the time T5 from when the energizing signal is applied until the first rise in acceleration is measured. Alternatively, the evaluation unit 22 reads the reference injection response delay time from the storage unit 24 and sets this time as time T5. The evaluation unit 22 also reads the time-series acceleration measurement values ​​of the fuel injector 4 under evaluation from the storage unit 24 and calculates the time T6 from when the energizing signal is applied until the first rise in acceleration is measured. The evaluation unit 22 calculates the difference between time T6 and time T5 as the compensation value for the injection response delay time. Next, the output unit 23 outputs the compensation value to a display device or the like (corresponding to step S4 in Figure 3). The output compensation value is set in the control device of the engine on which the fuel injector 4 under evaluation is installed.

[0038] (effect) According to the third embodiment, even when it is difficult to place pressure sensors 6 and strain gauges 7 in the fuel supply system 10, the injection response delay time of each individual fuel injector can be easily evaluated. In the above embodiment, the first rise of vibration was detected, but the second or third rise of vibration may be detected, and the compensation value may be calculated based on the time difference between the reference injection response delay time (more precisely, the time from when the energizing signal is applied until the rise of the second or third vibration is measured) and the vibration rise of the individual being evaluated. Alternatively, when detecting the first rise, the time measured for the fuel injector 4 being evaluated from when the energizing signal is applied until the rise of the first vibration is measured may be considered as the injection response delay time (instead of the time from when the energizing signal is applied until the fuel is actually injected). In this case, the compensation value may be calculated by calculating the difference between this time and the injection response delay time of one or more reference fuel injectors 4 (or the average value of the injection response delay times of the fuel injectors 4 in the case of multiple fuel injectors) calculated in the same manner.

[0039] Figure 7 is a schematic block diagram showing the hardware configuration of an evaluation system according to an embodiment. The computer 90 includes a processor 91, main memory 92, storage 93, and interface 94. The measurement device 20 and control device 30 described above are each implemented in separate computers 90. The operation of each processing unit described above is stored in the storage 93 in the form of a program. The processor 91 reads the program from the storage 93, loads it into the main memory 92, and executes the above processing according to the program. The processor 91 also allocates memory areas in the main memory 92 corresponding to each of the above-mentioned memory units according to the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0040] The program may be for implementing some of the functions that the computer 90 is to perform. For example, the program may perform functions in combination with other programs already stored in storage, or in combination with other programs implemented in other devices. In other embodiments, the computer 90 may be equipped with a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also included as an example of a processor.

[0041] Examples of storage 93 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of the computer 90, or an external medium connected to the computer 90 via an interface 94 or a communication line. Furthermore, if this program is distributed to the computer 90 via a communication line, the computer 90 that receives the program may expand it into the main memory 92 and execute the above processing. In at least one embodiment, storage 93 is a tangible storage medium that is not temporary. The program may also be for implementing some of the functions described above. Moreover, the program may be a so-called differential file (differential program) that implements the functions described above in combination with other programs already stored in storage 93.

[0042] As described above, several embodiments relating to this disclosure have been explained, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. For example, the first to third embodiments may be combined in any way. For instance, when combining the first and second embodiments, both a pressure sensor 6 and a strain gauge 7 may be provided in the fuel supply system 10, and the average of the compensation value calculated using the method of the first embodiment and the compensation value calculated using the method of the second embodiment may be used as the compensation value. Alternatively, when combining the first to third embodiments, both a pressure sensor 6 and a strain gauge 7 may be provided in the fuel supply system 10, a vibration sensor 8 may be provided in the fuel injection valve 4, and the average of the compensation values ​​calculated using the methods of the first to third embodiments may be used as the compensation value. The same applies to other combinations.

[0043] <Note> The evaluation apparatus, evaluation system, evaluation method, and program described in each embodiment can be understood, for example, as follows.

[0044] (1) An evaluation device according to the first embodiment is an evaluation device for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, and comprises: means for acquiring a measured value of a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector; means for measuring the response time from the time the open command is issued until the measured value changes; and means for evaluating individual differences in the injection response delay time of a fuel injector to be evaluated by calculating the difference between a predetermined first response time that serves as a reference and a second response time measured for the fuel injector to be evaluated. This makes it possible to easily evaluate individual differences in the injection response delay time of fuel injectors.

[0045] (2) An evaluation device according to the second embodiment is an evaluation device for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, comprising: means for acquiring a measured value of a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector; means for measuring the response time from the time the open command is issued until the measured value changes; means for calculating the injection response delay time based on the response time; and means for evaluating individual differences in the injection response delay time of a fuel injector to be evaluated by calculating the difference between a predetermined first injection response delay time that serves as a reference and a second injection response delay time measured for the fuel injector to be evaluated. This makes it possible to easily evaluate individual differences in the injection response delay time of fuel injectors.

[0046] (3) The evaluation device according to the third embodiment is the evaluation device according to (1) to (2), wherein the sensor is a pressure sensor that detects a pressure drop in the fuel injector caused by the injection of fuel from the fuel injector, and the pressure sensor is provided on the upstream side of the fuel injector in the fuel supply system. By simply installing a pressure sensor, it is possible to evaluate individual differences in the injection response delay time of fuel injectors.

[0047] (4) The evaluation device according to the fourth embodiment is the evaluation device according to (1) to (3), wherein the sensor is a strain gauge that detects a change in the amount of strain of the components constituting the fuel supply system caused by the pressure drop of the fuel injector that occurs when fuel is injected from the fuel injector, and the strain gauge is provided on the upstream side of the fuel injector in the fuel supply system. By simply attaching strain gauges, it is possible to evaluate individual differences in the injection response delay time of fuel injectors.

[0048] (5) The evaluation device according to the fifth embodiment is the evaluation device according to (1) to (4), wherein the sensor is a vibration sensor that detects vibrations of the fuel injector caused by the injection of fuel from the fuel injector, and the vibration sensor is provided on the fuel injector. By simply attaching a vibration sensor, it is possible to evaluate individual differences in the injection response delay time of fuel injectors.

[0049] (6) The evaluation system according to the sixth embodiment comprises a fuel supply system equipped with a fuel injector for injecting fuel, a control device for controlling the fuel injector, a sensor for detecting a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, and an evaluation device according to any one of (1) to (5).

[0050] (7) An evaluation method relating to the seventh aspect is an evaluation method for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, comprising the steps of: acquiring a measured value of a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector; measuring the response time from the time the open command is issued until the measured value changes; and evaluating individual differences in the injection response delay time of the fuel injector to be evaluated by calculating the difference between a predetermined first response time that serves as a reference and a second response time measured for the fuel injector to be evaluated.

[0051] (8) The program according to the eighth aspect causes a computer to perform a process for evaluating the injection response delay time from the time an open command is issued to a fuel injector provided in a fuel supply system until fuel is injected from the fuel injector, the process comprising: acquiring a measured value from a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector; measuring the response time from the time the open command is issued until the measured value changes; and calculating the difference between a predetermined first response time that serves as a reference and a second response time measured for the fuel injector to be evaluated, thereby evaluating individual differences in the injection response delay time of the fuel injector to be evaluated. [Explanation of Symbols]

[0052] 1. Fuel tank 2. High-pressure pump 3. Accumulator 4. Fuel Injector 5. Piping 6. Pressure sensor 7. Strain gauges 8. Vibration sensor 10...Fuel supply system 20. Measuring device 21... Acquisition section 22. Evaluation Department Output section of 23... 24...Storage section 30.. Control device 90... Computer 91... Processor 92···Main Memory 93.. Storage 94. Interface 100-level rating system

Claims

1. An evaluation device for evaluating the injection response delay time from the time an open command is issued to a fuel injection valve provided in a fuel supply system until fuel is injected from the fuel injection valve, Means for acquiring measured values ​​from a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, Means for measuring the response time from the time the opening command is issued until the measured value changes, A means for evaluating individual differences in the injection response delay time of the fuel injector being evaluated, by calculating the difference between a predetermined first response time that serves as a standard and a second response time measured for the fuel injector being evaluated, An evaluation device equipped with the following features.

2. An evaluation device for evaluating the injection response delay time from the time an open command is issued to a fuel injection valve provided in a fuel supply system until fuel is injected from the fuel injection valve, Means for acquiring measured values ​​from a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, Means for measuring the response time from the time the opening command is issued until the measured value changes, A means for calculating the injection response delay time based on the response time, A means for evaluating individual differences in the injection response delay time of a fuel injector to be evaluated, by calculating the difference between a predetermined first injection response delay time that serves as a standard and a second injection response delay time measured for the fuel injector to be evaluated. An evaluation device equipped with the following features.

3. The sensor is a pressure sensor that detects a pressure drop in the fuel injector caused by the injection of fuel from the fuel injector, and the pressure sensor is provided on the upstream side of the fuel injector in the fuel supply system. The evaluation apparatus according to claim 1 or claim 2.

4. The sensor is a strain gauge that detects changes in the amount of strain in the components of the fuel supply system caused by the pressure drop in the fuel injector resulting from the injection of fuel from the fuel injector, and the strain gauge is provided on the upstream side of the fuel injector in the fuel supply system. The evaluation apparatus according to claim 1 or claim 2.

5. The sensor is a vibration sensor that detects vibrations of the fuel injector caused by the injection of fuel from the fuel injector, and the vibration sensor is provided on the fuel injector. The evaluation apparatus according to claim 1 or claim 2.

6. A fuel supply system equipped with a fuel injector that injects fuel, A control device for controlling the fuel injection valve, A sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, An evaluation apparatus according to claim 1 or claim 2, An evaluation system equipped with the following features.

7. A computer-based evaluation method for evaluating the injection response delay time from the time an open command is issued to a fuel injector in a fuel supply system until fuel is injected from the fuel injector, The steps include acquiring measured values ​​from a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, A step of measuring the response time from the time the open command is issued until the measured value changes, The steps include: evaluating individual differences in the injection response delay time of the fuel injector being evaluated by calculating the difference between a predetermined first response time that serves as a standard and a second response time measured for the fuel injector being evaluated; A method of evaluation that includes [something].

8. On the computer, A process for evaluating the injection response delay time from the time an open command is issued to a fuel injector in a fuel supply system until fuel is injected from the fuel injector, The steps include acquiring measured values ​​from a sensor that detects a change in the state of the fuel supply system or the fuel injector caused by the injection of fuel from the fuel injector, A step of measuring the response time from the time the open command is issued until the measured value changes, The steps include: evaluating individual differences in the injection response delay time of the fuel injector being evaluated by calculating the difference between a predetermined first response time that serves as a standard and a second response time measured for the fuel injector being evaluated; A program that performs a process that has the following characteristics.

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