Evaluation device, evaluation system, evaluation method, and program

Abstract

The present invention provides a method for easily evaluating an individual difference in the injection response delay time of a fuel injection valve that supplies fuel to an engine. A measurement device evaluates an injection response delay time from when an opening command is given to a fuel injection valve provided in a fuel supply system to when fuel is injected from the fuel injection valve, the measurement device comprising: a means for acquiring a measured value of a sensor that detects a change in state of the fuel supply system or the fuel injection valve caused by injection of fuel from the fuel injection valve; a means for measuring a response time from when the opening command is given to when the measured value changes; and a means for calculating the difference between a predetermined first response time to be a reference and a second response time measured for the fuel injection valve to be evaluated and thereby evaluating an individual difference in the injection response delay time of the fuel injection valve to be evaluated.

Description

Evaluation Device, Evaluation System, Evaluation Method, and Program

[0001] The present disclosure relates to an evaluation device, an evaluation system, an evaluation method, and a program for a fuel injection device. The present disclosure claims priority based on Japanese Patent Application No. 2024-170782 filed in Japan on September 30, 2024, and incorporates the content thereof herein.

[0002] In an engine (e.g., a diesel engine) that injects fuel into a cylinder for self-ignition, it is necessary to precisely control the timing at which fuel is actually injected from the fuel injection valve from viewpoints such as engine performance, vibration, emissions, and durability. 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 fuel injection timing, 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 control method.

[0003] Japanese Patent Application Laid-Open No. 2022-74995

[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 for 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, resulting in a complex equipment configuration and an increase in equipment investment costs.

[0005] The present disclosure provides an evaluation device, an evaluation system, an evaluation method, and a program that can solve the above problems.

[0006] According to one aspect of the present disclosure, the evaluation 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.

[0007] According to one aspect of the present disclosure, the evaluation system 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] According to one aspect of the present disclosure, the evaluation method 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.

[0009] According to one aspect of the present disclosure, a program 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.

[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.

[0011] This is a schematic diagram of the evaluation system according to the first embodiment. This is a diagram illustrating the evaluation method for injection response delay time according to the first embodiment. This is a first flowchart showing an example of the evaluation process for injection response delay time according to the first embodiment. This is a second flowchart showing an example of the evaluation process for injection response delay time according to the first embodiment. This is a schematic diagram of the evaluation system according to the second embodiment. This is a schematic diagram of the evaluation system according to the third embodiment. This is a diagram illustrating the evaluation method for injection response delay time according to the third embodiment. This is a schematic diagram showing an example of the hardware configuration of the evaluation system according to each embodiment.

[0012] <First Embodiment> Hereinafter, a method for evaluating individual differences in the injection response delay time of fuel injectors according to this embodiment will be described with reference to Figures 1 to 3. Figure 1 is a schematic configuration 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, the fuel and air mixed in a certain ratio ignite and burn when they reach 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 a certain number of 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 device.

[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 to 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 includes 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 evaluation method for 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] In Figure 2(a), the vertical axis represents current, and the horizontal axis represents time. The current is the current of the open command (energy supply signal) output by the control device 30 to the fuel injector 4. Graph 200 shows the progression of the energy supply signal. When the current value of the command signal exceeds a predetermined value, an open command is issued to the fuel injector 4. In the case of Figure 2(a), an open command is output to the fuel injector 4 at time t0.

[0017] In Figure 2(b), the vertical axis represents the injection rate and the horizontal axis represents time. Graphs 201 to 203 show the changes in the injection rate. Graph 201 shows the changes in the injection rate of a certain fuel injector 4 (referred to as individual A). Graph 202 shows the changes in the injection rate of a fuel injector 4 different from individual A (referred to as individual B). Graph 203 shows the changes in the injection rate of a fuel injector 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 using specialized 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] In Figure 2(c), the vertical axis represents pressure in the fuel injector 4, and the horizontal axis represents time. Graphs 204 to 206 show the pressure changes of individuals A to C, respectively. These graphs can be obtained, for example, by installing a pressure sensor inside the fuel injector 4 and measuring the pressure. When an energizing signal is applied to the fuel injector 4, the valve body lifts and injection begins, causing high-pressure fuel to be discharged, which reduces the pressure inside the fuel injector 4. This pressure drop propagates upstream through the fuel supply system 10. As shown in graph 204, the pressure of individual A begins to decrease at time t1. Similarly, referring to graphs 205 and 206, the pressure drops of individuals B and C begin at times t2 and t3, respectively. In other words, the response delay of fuel injection in individuals A to C can also be measured by monitoring the pressure fluctuations (decrease) of individuals A to C.

[0019] In Figure 2(d), the vertical axis represents the pressure measured by the pressure sensor 6, and the horizontal axis represents time. Graphs 207 to 209 show the changes in pressure measured by the pressure sensor 6 installed upstream of individual A to C, respectively. The delay time from the application of the energization signal to the fuel injector 4 to the detection of a pressure drop by the pressure sensor 6 is the sum of the injection response delay time and the time it takes for the pressure drop generated in the fuel injector 4 to propagate to the pressure sensor 6. The time it takes for the pressure drop generated in the fuel injector 4 to propagate to the pressure sensor 6 depends on the distance within the fuel supply system 10 from the injection hole of the fuel injector 4 to the pressure sensor 6 and the speed of sound in the fuel. Here, since the pressure sensor 6 is installed in the same position in all of individual A to C, the time it takes for the pressure drop generated in each of individual A to C to propagate to the pressure sensor 6 is the same for individual A to individual C. Therefore, the time from the application of the energizing signal to the fuel injector 4 to the detection of a pressure drop by the pressure sensor 6 is highly correlated with the injection response delay time. The time difference from the output of the energizing signal to individuals A to C until the detection of a pressure drop by the pressure sensor 6 corresponds to the individual difference in the injection response delay time of individuals A to C.

[0020] By comparing the time from the application of an energizing signal to the fuel injector 4 to the detection of a pressure drop by the pressure sensor 6 with that of the fuel injector 4 under evaluation and a reference fuel injector 4, it is possible to calculate the time difference (individual difference) with the reference injection response delay time with the same level of accuracy as when measuring the fuel flow rate (injection rate) per unit time injected from each individual fuel injector 4 using a dedicated measuring device. By compensating for 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.

[0021] (Operation) Figure 3A is a first flowchart showing an example of the injection response delay time evaluation process according to the first embodiment. The acquisition unit 21 acquires time-series pressure measurement values ​​of one or more reference fuel injectors 4 (for example, individual A or multiple fuel injectors 4) (step S1). The acquisition unit 21 acquires time-series pressure measurement values ​​measured by the pressure sensor 6 when an energizing signal is applied to the fuel injector 4 from the control device 30 for the reference fuel injector 4, and records them in the storage unit 24. Next, the acquisition unit 21 acquires time-series pressure measurement values ​​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 measurement values ​​measured by the pressure sensor 6 when an energizing signal is applied to the fuel injector 4 from the control device 30 for the fuel injector 4 to be evaluated, and records them in the storage unit 24. Next, the evaluation unit 22 calculates the 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 (or 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 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 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 to the control device of the engine in which the fuel injector 4 to be evaluated will be installed after shipment. For example, the control unit 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 system to apply the energizing signal to the fuel injector 4 earlier by a compensation value (time T2 - time T1). This allows the fuel injector 4, even with an injection response delay time T2, to inject fuel at the desired timing.The setting of compensation values ​​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 energizing 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. A specific example of this process is shown in Figure 3B. Figure 3B is a second flowchart showing an example of the evaluation process for injection response delay time 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 premise, it is assumed that the time from the application of the energizing signal to the detection of a pressure drop has been measured for multiple fuel injectors 4 in advance, and that the average value of these values ​​has been registered in the storage unit 24 as the reference injection response delay time. First, the acquisition unit 21 acquires the 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 obtained 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). 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] (Effects) As described above, in this embodiment, when fuel injection starts, the pressure drop propagating through the fuel supply system 10 starting from the fuel injection valve 4 is detected by a pressure sensor 6 installed upstream of the fuel injection valve 4. Based on the time from the application of the energization signal to the fuel injection valve 4 to the detection of the pressure drop by the pressure sensor 6, the injection response delay time of each individual unit is determined and compensated for. As a result, when determining the injection response delay time of each individual unit during the factory operation of the fuel injection valve 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 of 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 state of the surface 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 explained 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 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 of a predetermined value or more 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 reads the time-series strain measurement values ​​of the fuel injector 4 to be evaluated 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 being evaluated is installed.

[0029] (Effects) 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. The 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 (in the case of multiple fuel injectors, the average value of the injection response delay times of the fuel injectors 4) calculated in the same manner.

[0030] <Third Embodiment> Hereinafter, an evaluation system 100b according to the third embodiment of the present invention will be described with reference to Figures 5 and 6. Figure 5 is a schematic configuration diagram of the evaluation system according to the third embodiment. The evaluation system 100b is equipped with a vibration sensor 8 in place 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 injection valve 4 of the fuel supply system 10 before shipment, and the injection response delay time of the fuel injection valve 4 is evaluated by analyzing the measurement results of the vibration sensor 8 with the 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 the 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 injected from 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 the fuel injector 4 exceeds 0 at time t1. Since the fuel injection command is output at time t0, the injection response delay time of the 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 rise in vibration 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 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. By compensating for 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) calculated based on time-series acceleration measurement values ​​measured for multiple fuel injectors 4 in advance, 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 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] (Effects) 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 a 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. 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 and the injection response delay time of one or more reference fuel injectors 4 (in the case of multiple, the average value of the injection response delay times of the fuel injectors 4) 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 allocates storage areas in the main memory 92 corresponding to each of the above-mentioned storage 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 include, in addition to or instead of the above configuration, a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device). 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. When this program is delivered to the computer 90 via a communication line, the computer 90 that receives the delivery may expand the program 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 be for realizing some of the functions described above. Furthermore, the program may be a so-called differential file (differential program) that realizes the functions described above in combination with other programs already stored in storage 93.

[0042] As described above, some embodiments according to the present disclosure have been explained. However, all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and the equivalent scope thereof. For example, the first embodiment to the third embodiment may be arbitrarily combined. For example, when combining the first embodiment and the second embodiment, both a pressure sensor 6 and a strain gauge 7 may be provided in the fuel supply system 10, and an average value of the compensation value calculated by the method of the first embodiment and the compensation value calculated by the method of the second embodiment may be used as the compensation value. For example, when combining the first embodiment to the third embodiment, 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 an average value of the compensation values calculated by the methods of the first embodiment to the third embodiment may be used as the compensation value. The same applies to other combinations.

[0043] <Supplementary Note> The evaluation device, evaluation system, evaluation method, and program described in each embodiment are understood as follows, for example.

[0044] (1) An evaluation device according to a first aspect is an evaluation device that evaluates an injection response delay time from when an opening command is instructed to a fuel injection valve provided in a fuel supply system until fuel is injected from the fuel injection valve, the evaluation device including means for acquiring a measured value of a sensor that detects a state change of the fuel supply system or the fuel injection valve caused by injection of fuel from the fuel injection valve, means for measuring a response time from when the opening command is instructed until the measured value changes, and means for evaluating an individual difference in the injection response delay time of the fuel injection valve to be evaluated by calculating a difference between a predetermined first said response time serving as a reference and a second said response time measured for the fuel injection valve to be evaluated. Thereby, the individual difference in the injection response delay time of the fuel injection valve can be easily evaluated.

[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, 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, 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 a fuel injector.

[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 the pressure sensor, individual differences in the injection response delay time of the fuel injector can be evaluated.

[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 the strain gauge, individual differences in the injection response delay time of the fuel injector can be evaluated.

[0048] (5) The evaluation device according to the fifth aspect is the evaluation device of (1) to (4), wherein the sensor is a vibration sensor that detects vibration of the fuel injection valve caused by fuel injection from the fuel injection valve, and the vibration sensor is provided on the fuel injection valve. By simply attaching the vibration sensor, the individual difference in the injection response delay time of the fuel injection valve can be evaluated.

[0049] (6) The evaluation system according to the sixth aspect includes a fuel supply system including a fuel injection valve that injects fuel, a control device that controls the fuel injection valve, a sensor that detects a change in the state of the fuel supply system or the fuel injection valve caused by fuel injection from the fuel injection valve, and the evaluation device according to any one of (1) to (5).

[0050] (7) The evaluation method according to the seventh aspect is an evaluation method for evaluating the injection response delay time from when an opening command is instructed to the fuel injection valve provided in the fuel supply system until fuel is injected from the fuel injection valve, the method including: obtaining a measurement value of a sensor that detects a change in the state of the fuel supply system or the fuel injection valve caused by fuel injection from the fuel injection valve; measuring a response time from when the opening command is instructed until the measurement value changes; and evaluating an individual difference in the injection response delay time of the fuel injection valve to be evaluated by calculating a difference between a predetermined first response time serving as a reference and a second response time measured for the fuel injection valve 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.

[0052] 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.

[0053] 1... Fuel tank 2... High-pressure pump 3... Accumulator 4... Fuel injector 5... Piping 6... Pressure sensor 7... Strain gauge 8... Vibration sensor 10... Fuel supply system 20... Measurement device 21... Acquisition unit 22... Evaluation unit 23... Output unit 24... Memory unit 30... Control device 90... Computer 91... Processor 92... Main memory 93... Storage 94... Interface 100... Evaluation system

Claims

1. An evaluation device 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, 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; 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.

2. An evaluation device 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, 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.

3. The evaluation device according to claim 1 or claim 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.

4. The evaluation device according to claim 1 or 2, wherein the sensor is a strain gauge that detects a change in the amount of strain of a component constituting the fuel supply system caused by a 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.

5. The evaluation device according to claim 1 or claim 2, 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.

6. An evaluation system comprising: 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.

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, 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 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.

8. A program that causes a computer to execute 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.

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