JP2015078680A - Illegal modification detecting device of fuel injection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illegal modification detecting device capable of detecting illegal modification to a fuel injection system.SOLUTION: An illegal modification detecting device 30 includes a storing portion 34 for storing a first characteristic as a characteristic of a fuel injection system in a state free from illegal modification, an acquiring portion 35 for acquiring a second characteristic as the present characteristic of the fuel injection system, and a detecting portion 36 for detecting the illegal modification to the fuel injection system, when the first characteristic stored in the storing portion 34 and the second characteristic acquired by the acquiring portion 35 are different from the predetermined ones.

Description

  The present invention relates to an apparatus for detecting tampering with a fuel injection system.

  2. Description of the Related Art Conventionally, there is a technique that estimates a fuel injection state based on a pressure change in a fuel passage accompanying fuel injection and controls a fuel injection state by a fuel injection system to a target injection state (see Patent Document 1).

JP 2008-144749

  Incidentally, the fuel injection system may be tampered with after factory shipment. When unauthorized modification is performed, the output characteristics of the sensor may change. For this reason, even if the fuel injection state is controlled to the target injection state based on the detection value by the sensor, the actual injection state may be different from the target injection state.

  The present invention has been made to solve these problems, and a main object of the present invention is to provide a tampering detection device capable of detecting tampering with a fuel injection system.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  The present invention is a tampering detection device for a fuel injection system, which is a storage unit that stores a first characteristic that is a characteristic of a fuel injection system that has not been tampered with, and present characteristics of the system. If the acquisition unit that acquires the second characteristic and the first characteristic stored in the storage unit and the second characteristic acquired by the acquisition unit are different from each other than a predetermined value, the system is illegal. And a detector for detecting that the remodeling has been performed.

  According to the above configuration, the storage unit stores the first characteristic that is the characteristic of the fuel injection system that has not been tampered with, for example, the characteristic at the time of factory shipment. And the 2nd characteristic which is the present characteristic of a fuel injection system is acquired by an acquisition part.

  Here, tampering with the fuel injection system is often performed for the purpose of causing the fuel injection system to perform control different from the design. For this reason, when an unauthorized modification is made to the fuel injection system, the current characteristic (second characteristic) of the fuel injection system is changed from the characteristic (first characteristic) in a state where the unauthorized modification is not performed. It becomes. Therefore, when the first characteristic and the second characteristic are different from each other than the predetermined value, it is possible to detect that unauthorized modification has been made to the fuel injection system.

The schematic diagram which shows the outline of a fuel-injection system. The time chart which shows the change of the injection rate and fuel pressure corresponding to an injection command signal. The block diagram which shows the outline | summarys, such as a setting of the injection command signal with respect to a fuel injection valve. The flowchart which shows the calculation procedure of an injection rate parameter. The graph which shows the output value, fuel pressure parameter, and injection rate of a fuel pressure sensor before and after unauthorized modification. The flowchart which shows the process sequence of the unauthorized modification detection of 1st Embodiment. The flowchart which shows the process sequence of the unauthorized modification detection of 2nd Embodiment. The graph which shows the change of the actual pressure accompanying the fuel injection before and after unauthorized modification. The graph which shows the relationship between the engine start frequency and the discharge amount of a fuel pump. The flowchart which shows the process sequence of the unauthorized modification detection of 3rd Embodiment. The flowchart which shows the process sequence of the unauthorized modification detection of 4th Embodiment.

(First embodiment)
Hereinafter, a first embodiment will be described with reference to the drawings. The present embodiment is embodied as a fuel injection system mounted on a vehicle engine (internal combustion engine). This engine is assumed to be a multi-cylinder diesel engine that injects high pressure fuel into a plurality of cylinders and performs compression self-ignition combustion.

  FIG. 1 shows a fuel injection valve 10 mounted on each cylinder (# 1 to # 4) of the engine, a fuel pressure sensor 20 mounted on each fuel injection valve 10, and an electronic control device mounted on a vehicle. It is a schematic diagram which shows ECU30 grade | etc.,.

  First, an engine fuel injection system including the fuel injection valve 10 will be described. The fuel in the fuel tank 40 is pumped by the fuel pump 41 to the common rail 42 (pressure accumulating vessel) and held in a pressure accumulating state, and is distributed and supplied to the fuel injection valves 10 (# 1 to # 4) of each cylinder through the high pressure pipe 42b. The The plurality of fuel injection valves 10 (# 1 to # 4) sequentially inject fuel in a preset order. In this embodiment, it is assumed that injection is performed in the order of # 1 → # 3 → # 4 → # 2.

  In addition, since the plunger pump is used for the fuel pump 41 (pump), fuel is pumped in synchronism with the reciprocation of the plunger. Since the fuel pump 41 is driven by the crankshaft using the engine output as a drive source, the fuel is pumped from the fuel pump 41 a predetermined number of times during one combustion cycle.

  The fuel injection valve 10 includes a body 11, a needle-shaped valve body 12, an actuator 13, and the like described below. The body 11 forms a high-pressure passage 11a therein and an injection hole 11b for injecting fuel. The valve body 12 is accommodated in the body 11 and opens and closes the injection hole 11b. The high-pressure pipe 42b and the high-pressure passage 11a constitute a fuel passage.

  A back pressure chamber 11c for applying a back pressure to the valve body 12 is formed in the body 11, and the high pressure passage 11a and the low pressure passage 11d are connected to the back pressure chamber 11c. The communication state between the high pressure passage 11 a and the low pressure passage 11 d and the back pressure chamber 11 c is switched by the control valve 14. When the actuator 13 such as an electromagnetic coil or a piezoelectric element is energized and the control valve 14 is pushed downward in FIG. 1, the back pressure chamber 11c communicates with the low pressure passage 11d and the fuel pressure in the back pressure chamber 11c decreases. To do. As a result, the back pressure applied to the valve body 12 is lowered and the valve body 12 is lifted up (opening operation). Thereby, the seat surface 12a of the valve body 12 is separated from the seat surface 11e of the body 11, and fuel is injected from the injection hole 11b.

  On the other hand, when the actuator 13 is turned off and the control valve 14 is operated upward in FIG. 1, the back pressure chamber 11c communicates with the high pressure passage 11a and the fuel pressure in the back pressure chamber 11c increases. As a result, the back pressure applied to the valve body 12 increases and the valve body 12 is lifted down (closed valve operation). Thereby, the seat surface 12a of the valve body 12 is seated on the seat surface 11e of the body 11, and the fuel injection from the injection hole 11b is stopped.

  Therefore, the ECU 30 controls the energization of the actuator 13 so that the opening / closing operation of the valve body 12 is controlled. Thereby, the high-pressure fuel supplied from the common rail 42 to the high-pressure passage 11 a is injected from the injection hole 11 b according to the opening / closing operation of the valve body 12.

  The fuel pressure sensor 20 (sensor, predetermined fuel pressure sensor) is mounted on all the fuel injection valves 10 and includes a stem 21 (a strain generating body) and a pressure sensor element 22 described below. The stem 21 is attached to the body 11, and the diaphragm portion 21a formed on the stem 21 is elastically deformed by receiving the pressure of the high-pressure fuel flowing through the high-pressure passage 11a. The pressure sensor element 22 is attached to the diaphragm portion 21a, and outputs an analog pressure detection signal corresponding to the amount of elastic deformation generated in the diaphragm portion 21a to the ECU 30.

  Specifically, the pressure sensor element 22 is connected to the mold IC 24. The mold IC 24 includes an amplifier circuit that amplifies the detection signal output from the pressure sensor element 22, a filtering circuit that removes noise superimposed on the detection signal, a circuit that applies a voltage to the pressure sensor element 22, and the like. The pressure sensor element 22 to which a voltage is applied from the voltage application circuit constitutes a bridge circuit in which the resistance value changes according to the magnitude of strain generated in the diaphragm portion 21a. As a result, the output voltage of the bridge circuit changes according to the distortion of the diaphragm portion 21a, and this output voltage is output to the amplification circuit of the mold IC 24 as the pressure detection value of the high-pressure fuel. The amplifier circuit amplifies the analog pressure detection value output from the pressure sensor element 22 (bridge circuit), and outputs the amplified analog signal (continuous value) to the ECU 30.

  The ECU 30 (unauthorized alteration detection device) is a well-known microcomputer including a CPU, a ROM, a RAM, a storage device, an input / output interface, and the like. The ECU 30 calculates a target injection state (for example, the number of injection stages, the injection start timing, the injection end timing, the injection amount, etc.) based on the operation amount of the accelerator pedal, the engine load, the engine rotational speed NE, and the like. For example, the optimal injection state corresponding to the engine load and the engine speed is stored as an injection state map. Based on the current engine load and engine speed, the target injection state is calculated with reference to the injection state map. Further, the ECU 30 controls the discharge amount of the fuel pump 41 so that the fuel pressure in the common rail 42 becomes the fuel pressure corresponding to the target injection state. Then, the ECU 30 sets the injection command signals t1, t2, and Tq (see FIG. 2A) corresponding to the calculated target injection state based on the injection rate parameters td, te, Rα, Rβ, and Rmax described in detail later. The operation of the fuel injection valve 10 is controlled by outputting to the fuel injection valve 10. The ECU 30 constitutes a storage unit 34, an acquisition unit 35, a detection unit 36, and a restriction unit 37.

  Next, a method of injection control when fuel is injected from the fuel injection valve 10 will be described with reference to FIGS.

  The ECU 30 samples (extracts) an analog pressure detection value output from the fuel pressure sensor 20 at a set sampling rate. Then, the ECU 30 converts the sampled extracted value into a digital pressure detection value. Based on this digital pressure detection value, the ECU 30 detects a change in fuel pressure caused by injection as a fuel pressure waveform (see FIG. 2C).

  Based on the detected fuel pressure waveform, the ECU 30 calculates an injection rate waveform (see FIG. 2B) that represents a change in the fuel injection rate, and detects an injection state. Then, while learning the injection rate parameters Rα, Rβ, and Rmax that specify the detected injection rate waveform (injection state), the correlation between the injection command signals (pulse-on timing t1, pulse-off timing t2, and pulse-on period Tq) and the injection state. The injection rate parameters td and te for specifying Further, the storage unit 34 of the ECU 30 stores injection rate parameters td, te, Rα, Rβ, and Rmax (first characteristics) at the time of factory shipment (a state in which unauthorized modification is not performed).

  FIG. 3 is a block diagram showing an outline of learning of these injection rate parameters (injection parameters), setting of an injection command signal to be output to the fuel injection valve 10, and the like. About each means 31, 32, 33 functioning by the ECU 30 This will be described below. The injection rate parameter calculation means 31 (acquisition part) calculates the current injection rate parameters td, te, Rα, Rβ, Rmax (second characteristic) based on the fuel pressure waveform detected by the fuel pressure sensor 20.

  The learning unit 32 learns by updating the calculated injection rate parameter in the storage unit 34 of the ECU 30. Since the injection rate parameter varies depending on the supply fuel pressure (pressure in the common rail 42) at that time, the injection rate parameter can be learned in association with the supply fuel pressure or a reference pressure Pbase (see FIG. 2C) described later. desirable. In the example of FIG. 3, the injection rate parameter value corresponding to the fuel pressure is stored in the injection rate parameter map M.

  The setting means 33 (injection control unit) acquires an injection rate parameter (learned value) corresponding to the current fuel pressure from the injection rate parameter map M. And based on the acquired injection rate parameter, the injection command signals t1, t2, and Tq corresponding to the target injection state are set. Then, the fuel pressure when the fuel injection valve 10 is operated according to the injection command signal set in this way is detected by the fuel pressure sensor 20. The injection rate parameter calculation means 31 samples the detected fuel pressure (analog value) and converts it into a digital value, and detects a fuel pressure waveform based on this digital value. Then, the injection rate parameter calculation means 31 calculates injection rate parameters td, te, Rα, Rβ, Rmax based on the detected fuel pressure waveform.

  In short, an injection state (that is, injection rate parameters td, te, Rα, Rβ, Rmax) with respect to the injection command signal is detected and learned, and an injection command signal corresponding to the target injection state is set based on the learned value. Therefore, the injection command signal is feedback-controlled based on the detected injection state, and even if aged deterioration or the like proceeds, the detected injection state can be controlled with high accuracy so as to coincide with the target injection state. In particular, by performing feedback control to set the injection command period Tq based on the injection rate parameter so that the detected injection amount becomes the target injection amount, the detected injection amount is compensated so as to become the target injection amount. ing.

  Next, the procedure for calculating the injection rate parameter will be described with reference to the flowchart of FIG. 4 and FIG. Note that the process shown in FIG. 4 is repeatedly executed by the ECU 30 (acquisition unit 35).

  First, it is determined whether or not fuel injection has been performed in a preset analysis order cylinder (S605). The cylinders in this analysis order are set in the order of injection from # 1 → # 3 → # 4 → # 2.

  When it is determined that the injection is performed in the analysis order cylinder (S605: YES), the injection component Wb (injection waveform) used for calculating the injection rate parameter is calculated based on the detection value of the fuel pressure sensor 20 (S610). Specifically, based on the pressure detection value by the fuel pressure sensor 20 (injection sensor) of the cylinder (injection cylinder) that is injecting fuel, an injection component Wb that represents a change in fuel pressure in the injection sensor that occurs with the injection is generated.

  Subsequently, based on a reference waveform that is a waveform corresponding to a period until the fuel pressure starts to drop with the start of injection in the injection component Wb, the average fuel pressure of the reference waveform is calculated as the reference pressure Pbase (S611). ).

  Subsequently, an approximate straight line Lα of the descending waveform is calculated based on a descending waveform that is a waveform corresponding to a period in which the fuel pressure decreases as the injection rate increases in the injection component Wb (S612).

  Subsequently, an approximate straight line Lβ of the rising waveform is calculated based on the rising waveform that is the waveform corresponding to the period during which the fuel pressure increases as the injection rate decreases in the injection component Wb (S613).

  Subsequently, reference values Bα and Bβ are calculated based on the reference pressure Pbase (S614). For example, values lower than the reference pressure Pbase by a predetermined amount may be calculated as the reference values Bα and Bβ.

  Subsequently, a timing (intersection timing LBα between Lα and Bα) of the approximate straight line Lα that is the reference value Bα is calculated, and an injection start timing R1 is calculated based on the intersection timing LBα (S615). For example, a timing that is a predetermined delay time Cα before the intersection timing LBα may be calculated as the injection start timing R1.

  Subsequently, a timing (intersection timing LBβ between Lβ and Bβ) that is the reference value Bβ in the approximate straight line Lβ is calculated, and an injection end timing R4 is calculated based on the intersection timing LBβ (S616). For example, a timing that is a predetermined delay time Cβ before the intersection timing LBβ may be calculated as the injection end timing R4.

  In the subsequent step S617, the slope of the straight line Rα indicating an increase in the injection rate waveform shown in FIG. 2B is calculated based on the slope of the approximate straight line Lα. For example, the slope of Rα may be calculated by multiplying the slope of Lα by a predetermined coefficient. Note that, based on the injection start timing R1 calculated in S615 and the slope of Rα calculated in S617, the straight line Rα representing the rising portion of the injection rate waveform with respect to the injection command signal can be specified. Further, in S617, the slope of the straight line Rβ indicating the injection reduction in the injection rate waveform is calculated based on the slope of the approximate straight line Lβ. For example, the slope of Rβ may be calculated by multiplying the slope of Lβ by a predetermined coefficient. Note that, based on the injection end timing R4 calculated in S616 and the slope of Rβ calculated in S617, a straight line Rβ that represents the descending portion of the injection rate waveform with respect to the injection command signal can be specified.

  Subsequently, based on the straight lines Rα and Rβ of the injection rate waveform calculated in S617, a timing (valve closing operation start timing R23) at which the valve body 12 starts lift-down in response to the command to end injection is calculated ( S618). Specifically, the intersection of both straight lines Rα and Rβ is calculated, and the intersection timing is calculated as the valve closing operation start timing R23.

  In subsequent S619, a delay time (injection start delay time td) of the injection start timing R1 calculated in S615 with respect to the injection start command timing t1 is calculated. Further, in S619, a delay time (injection end delay time te) with respect to the injection end command timing t2 of the valve closing operation start timing R23 calculated in S618 is calculated.

  Subsequently, it is determined whether or not the pressure difference ΔPγ between the reference pressure Pbase and the intersection pressure Pαβ is less than a predetermined value ΔPγth (S620). If it is determined that ΔPγ <ΔPγth (S620: YES), in the subsequent S621, it is assumed that the injection is small injection (injection that ends before the injection rate reaches a certain maximum value), and the maximum injection is based on the pressure difference ΔPγ. The rate Rmax is calculated (Rmax = ΔPγ × Cγ). On the other hand, if it is determined that ΔPγ ≧ ΔPγth (S620: NO), in the subsequent S622, the maximum injection rate Rmax is calculated based on the maximum pressure drop amount ΔP from the reference pressure Pbase (Rmax = ΔP × Cγ). Thereafter, this series of processing is temporarily terminated (END).

  Thus, there is a correlation between the fuel pressure detected by the fuel pressure sensor 20 and the fuel injection state by the fuel injection valve 10, and the injection rate parameter indicating the injection state reflects the characteristics of the fuel injection system.

  Here, tampering with the fuel injection system is often performed for the purpose of causing the fuel injection system to perform control different from the design. For this reason, when an unauthorized modification is made to the fuel injection system, the current characteristic (second characteristic) of the fuel injection system is changed from the characteristic (first characteristic) in a state where the unauthorized modification is not performed. It becomes. In this case, for example, the detected value of the fuel pressure sensor 20 that outputs a voltage corresponding to the fuel pressure changes before and after the unauthorized modification.

  FIG. 5A is a graph showing changes in the output value of the fuel pressure sensor 20 accompanying fuel injection before and after unauthorized modification. As indicated by a solid line in the figure, before the tampering is performed, the output value (voltage) of the fuel pressure sensor 20 corresponding to the pressure graph shown in FIG. 2C is detected. However, after the unauthorized modification, even if the actual pressure level is the same, the detection value of the fuel pressure sensor 20 may become small as indicated by the alternate long and short dash line in FIG.

  In this case, as shown in FIGS. 5B and 5C, the injection parameters (fuel pressure parameter, injection rate parameter) acquired based on the detection value of the fuel pressure sensor 20 apparently change before and after the unauthorized modification. It will be.

  As shown in FIG. 5B, the slope (fuel pressure parameter) of the approximate straight line Lα of the descending portion of the output value waveform of the fuel pressure sensor 20 changes before and after the unauthorized modification. Specifically, the inclination of the approximate straight line Lα after unauthorized modification is apparently smaller than the inclination of the approximate line Lα before unauthorized modification. Further, the slope (fuel pressure parameter) of the approximate straight line Lβ of the rising portion of the output value waveform of the fuel pressure sensor 20 changes before and after the unauthorized modification. Specifically, the slope of the approximate straight line Lβ after unauthorized modification is apparently smaller than the slope of the approximate line Lβ before unauthorized modification. Further, the maximum pressure drop ΔP (fuel pressure parameter) from the reference pressure Pbase changes before and after the unauthorized modification. Specifically, the maximum pressure drop amount ΔP after unauthorized modification is apparently smaller than the maximum pressure drop amount ΔP before unauthorized modification.

  As shown in FIG. 5C, the slope (injection rate parameter) of the straight line Rα indicating the increase in injection in the injection rate waveform changes before and after the unauthorized modification. Specifically, the slope of the straight line Rα after unauthorized modification is apparently smaller than the slope of the straight line Rα before unauthorized modification. In addition, the slope (injection rate parameter) of the straight line Rβ indicating the decrease in injection in the injection rate waveform changes before and after the unauthorized remodeling. Specifically, the slope of the straight line Rβ after unauthorized modification is apparently smaller than the slope of the straight line Rβ before unauthorized modification. Further, the maximum injection rate Rmax (fuel pressure parameter) changes before and after unauthorized modification. Specifically, the maximum injection rate Rmax after unauthorized modification is apparently smaller than the maximum injection rate Rmax before unauthorized modification.

Therefore, in the present embodiment, the fuel pressure (common physical quantity) in the high-pressure passage 11a of the fuel injection system is detected by the plurality of fuel pressure sensors 20. The acquisition unit 35 acquires the injection rate parameter based on the detected values of the fuel pressure by the plurality of fuel pressure sensors 20. And in all the injection rate parameters acquired based on the detection values by the plurality of fuel pressure sensors 20, when the first characteristic and the second characteristic are different from a predetermined value, the system has been tampered with. Detect that.
FIG. 6 is a flowchart showing a processing procedure for unauthorized alteration detection. This series of processing is executed by the ECU 30 (detecting unit 36) at the time of fuel injection at a predetermined time after the engine is started.

  First, it is determined whether there is a cylinder in which the difference between the first characteristic and the second characteristic of the injection rate parameter is larger than a predetermined value (S11). Specifically, using the at least one of the injection rate parameters td, te, Rα, Rβ, and Rmax, the acquisition unit 35 acquires the first characteristic that is stored in the storage unit 34 and that is a state in the state of not being tampered with. It is determined whether there is a cylinder whose difference from the second characteristic which is the current characteristic of the fuel injection system is greater than a predetermined determination value. As this determination value, for example, a value that can be used to determine whether or not the difference between the first characteristic and the second characteristic is larger than several tens of percent.

  In the determination of S11, when it is determined that there is no cylinder in which the difference between the first characteristic and the second characteristic of the injection rate parameter is larger than the predetermined value (S11: NO), this series of processes is temporarily ended (END). On the other hand, if it is determined that there is a cylinder with the difference larger than a predetermined value (S11: YES), it is determined whether or not the difference is larger than the predetermined value for all the cylinders (S12).

  If it is determined in S12 that the difference is larger than a predetermined value for all cylinders (S12: YES), the difference is larger than the predetermined value for all cylinders between the previous operation and the current operation of the engine. It is determined whether or not (S13). That is, it is determined whether or not the difference is greater than a predetermined value in all cylinders during the previous operation of the engine, but whether or not the difference is greater than a predetermined value in all cylinders during the current operation of the engine.

  When it is determined in S12 that the difference is not greater than the predetermined value for all the cylinders (S12: NO), or when it is determined in S13 that there is no change between the previous operation and the current operation of the engine ( S13: NO), it is determined that this change is a change with time (S14). Then, this series of processing is temporarily ended (END).

  On the other hand, in the determination of S13, when it is determined that the above-mentioned difference has changed to a state larger than a predetermined value in all cylinders between the previous operation and the current operation of the engine (S13: YES), this change is due to unauthorized modification. Is detected (S15). That is, it detects that the fuel injection system has been tampered with. Then, this series of processing is temporarily ended (END).

  The embodiment described in detail above has the following advantages.

  -Tampering with the fuel injection system is often performed for the purpose of causing the fuel injection system to perform control different from the design. For this reason, when an unauthorized modification is made to the fuel injection system, the current characteristic (second characteristic) of the fuel injection system is changed from the characteristic (first characteristic) in a state where the unauthorized modification is not performed. It becomes. Therefore, when the first characteristic and the second characteristic are different from each other than the predetermined value, it is possible to detect that unauthorized modification has been made to the fuel injection system.

  When all the injection rate parameters (for example, the maximum injection rate Rmax) acquired based on the detected values of the fuel pressures by the plurality of fuel pressure sensors 20 have changed, the fuel pressure sensor 20 has not failed but an unauthorized modification is performed. It is highly possible that Therefore, in all of the second characteristics acquired based on the detected values of the fuel pressure by the plurality of fuel pressure sensors 20, the first characteristic and the second characteristic are illegal with respect to the fuel injection system when they are different from a predetermined value. It is possible to detect with high accuracy that remodeling has been performed.

  If the fuel injection system is tampered with, the fuel pressure detected by the fuel pressure sensor 20 may change before and after tampering. In this case, the injection parameters (fuel pressure parameter, injection rate parameter) acquired based on the detected value of the fuel pressure sensor 20 change before and after the unauthorized modification. Therefore, it is possible to detect that the fuel injection system has been tampered with by using the injection parameter as the characteristic of the fuel injection system.

  -When the difference between the first characteristic and the second characteristic has changed to a state larger than a predetermined value during the previous operation and the current operation of the engine, it is detected that unauthorized modification has been performed. For this reason, when unauthorized modification is performed from the end of the previous operation of the engine to the start of the current operation, the unauthorized modification can be detected with high accuracy.

  ・ If it is determined that the above difference is not greater than a predetermined value for all cylinders, or if it is determined that the engine has not changed between the previous operation and the current operation, this change is determined to be a change over time. Yes. For this reason, it can suppress detecting erroneously that the time-dependent change of a fuel-injection system is an unauthorized modification.

  Note that the above-described embodiment may be modified as follows.

  In the process of S12 of FIG. 6, it may be determined whether the difference between the first characteristic and the second characteristic is greater than a predetermined value for a plurality of cylinders, not all cylinders. In FIG. 6, the process of S12 or the process of S13 can be omitted. In FIG. 6, the processing of S12 to S14 can be omitted.

  ・ Instead of the injection rate parameters td, te, Rα, Rβ, and Rmax, unauthorized modification has been made based on fuel pressure parameters such as the slope of the approximate line Lα, the slope of the approximate line Lβ, and the maximum pressure drop ΔP. It can also be detected. Specifically, when the first characteristic and the second characteristic of the fuel pressure parameter are different from a predetermined value, it can be detected that an unauthorized modification has been made to the fuel injection system. Further, when the fuel pressure detected by the fuel pressure sensor 20 in a predetermined operating state of the engine is used as a characteristic of the fuel injection system, and the first characteristic and the second characteristic of the fuel pressure are different from a predetermined value, the fuel injection system It is also possible to detect that unauthorized modification has been made.

(Second Embodiment)
Hereinafter, the second embodiment will be described focusing on differences from the first embodiment. In the present embodiment, the fuel injection system is tampered with based on the pre-pressurization fuel pressure detected by the fuel pressure sensor 20 before the fuel in the fuel injection system is pressurized by the fuel pump 41. Is detected. The storage unit 34 stores the fuel pressure (first characteristic) detected by the fuel pressure sensor 20 in a state where the fuel injection system is opened to the atmosphere at the time of factory shipment (a state in which the tampering is not tampered with).

  FIG. 7 is a flowchart showing a processing procedure for unauthorized modification detection. This series of processing is executed by the ECU 30 (detecting unit 36) when the engine system is started.

  First, it is determined whether or not there is a cylinder in which the difference between the first characteristic and the second characteristic of the pre-pressurized fuel pressure, which is the fuel pressure when the atmosphere is released, is larger than a predetermined value (S21). Specifically, with respect to the fuel pressure detected by the fuel pressure sensor 20, the first characteristic stored in the storage unit 34, which is a characteristic in an unmodified state, and the current characteristic of the fuel injection system acquired by the acquisition unit 35. It is determined whether there is a cylinder whose difference from the second characteristic is greater than a predetermined determination value. As this determination value, for example, it is possible to determine whether or not the difference between the first characteristic and the second characteristic is larger than several tens of percent, and whether or not the difference is larger than several ten percent. Use possible values.

  In the determination of S21, when it is determined that there is no cylinder in which the difference between the first characteristic and the second characteristic of the fuel pressure before pressurization is larger than a predetermined value (S21: NO), this series of processes is temporarily ended (END). ). On the other hand, when it is determined that there is a cylinder having the difference larger than the predetermined value (S21: YES), it is determined whether the difference is larger than the predetermined value for all the cylinders (S22).

  When it is determined in S22 that the difference is larger than a predetermined value for all cylinders (S22: YES), the difference is larger than a predetermined value for all cylinders when the engine is started last time and when the current system is started. It is determined whether or not it has changed to (S23). That is, it is determined whether or not the difference is greater than a predetermined value in all cylinders when the engine is last activated, but whether or not the difference is greater than a predetermined value in all cylinders when the engine is activated this time.

  If it is determined in S22 that the above difference is not greater than the predetermined value for all cylinders (S22: NO), or it is determined in S23 that there is no change between the previous system startup and the current system startup. In the case (S23: NO), it is determined that this change is a change with time (S24). Then, this series of processing is temporarily ended (END).

  On the other hand, if it is determined in S23 that the difference has changed to a state larger than a predetermined value in all cylinders between the previous system startup and the current system startup (S23: YES), this change is an illegal modification. (S25). That is, it detects that the fuel injection system has been tampered with. Then, this series of processing is temporarily ended (END).

  This embodiment has the following advantages. Here, only the advantages different from the first embodiment will be described.

  -When all the detected values of the fuel pressure by the plurality of fuel pressure sensors 20 have changed, it is highly possible that the fuel pressure sensor 20 has not failed but has been tampered with. Therefore, in all the second characteristics in the detected values of the fuel pressure by the plurality of fuel pressure sensors 20, when the first characteristic and the second characteristic are different from a predetermined value, the fuel injection system has been tampered with. This can be detected with high accuracy.

  The fuel pressure before pressurization detected by the fuel pressure sensor 20 before the fuel in the fuel injection system is pressurized should be a pressure corresponding to the atmospheric pressure. Here, when an unauthorized modification is made to the fuel injection system, the detected value of the fuel pressure by the fuel pressure sensor 20 may change before and after the unauthorized modification. In that case, the fuel pressure before pressurization will deviate from the pressure corresponding to the atmospheric pressure. Therefore, by using the pre-pressurized fuel pressure as a characteristic of the fuel injection system, it is possible to detect with high accuracy that the fuel injection system has been tampered with.

  Note that the above-described embodiment may be modified as follows.

  In the process of S22 of FIG. 7, it may be determined whether the difference between the first characteristic and the second characteristic is greater than a predetermined value for a plurality of cylinders, not all cylinders. In FIG. 7, the process of S22 or the process of S23 can be omitted. In FIG. 7, the processing of S22 to S24 can be omitted.

  A rail pressure sensor for detecting the fuel pressure in the common rail 42 is provided, and the pre-pressurized fuel pressure detected by the rail pressure sensor is used, and the first characteristic and the second characteristic of the pre-pressurized fuel pressure are different from a predetermined value. In this case, it is also possible to detect that the fuel injection system has been tampered with. In that case, two rail pressure sensors are provided (double system), and when the first characteristic and the second characteristic of the pre-pressurized fuel pressure detected by the two rail pressure sensors are different from a predetermined value, It may be detected that an unauthorized modification has been made to the fuel injection system.

(Third embodiment)
Hereinafter, the third embodiment will be described focusing on differences from the first embodiment. In this embodiment, after the state where the difference between the first characteristic and the second characteristic of the discharge amount of the fuel pump 41 is smaller than a predetermined value is maintained for a predetermined period, the difference between the first characteristic and the second characteristic is determined. When a state larger than the predetermined value is maintained for a predetermined period, it is detected that the fuel injection system has been tampered with. The storage unit 34 stores a discharge amount (first characteristic) of fuel discharged by the fuel pump 41 in a predetermined operation state of the engine at the time of factory shipment (a state in which unauthorized modification is not performed).

  Even when the output value (voltage) of the fuel pressure sensor 20 changes due to unauthorized modification as shown in FIG. 5A, the fuel pressure is controlled to the target pressure based on the output value of the fuel pressure sensor 20. For this reason, as shown in FIG. 8, the actual fuel pressure change at the time of fuel injection changes from before the unauthorized modification indicated by the solid line to after the unauthorized modification indicated by the alternate long and short dash line. As a result, the amount of fuel injected from the fuel injection valve 10 increases, and accordingly, the amount of fuel discharged by the fuel pump 41 increases.

  FIG. 9 is a graph showing the relationship between the number of engine starts and the discharge amount of the fuel pump 41. In a predetermined operating state of the engine, the amount of fuel discharged by the fuel pump 41 is substantially constant. Here, as indicated by the solid line, even if the fuel discharge amount from the fuel pump 41 changes from the nth discharge amount at the (n + 1) th start, if it temporarily becomes an abnormal value due to noise or the like, n + 2 In the second start, the discharge amount returns to the same as the nth start. On the other hand, if the fuel injection system is tampered between the n-th start and the (n + 1) th start, the amount of fuel discharged by the fuel pump 41 changes at the (n + 1) th start, That state will be maintained. Therefore, in this embodiment, unauthorized modification is detected as follows.

  FIG. 10 is a flowchart showing a processing procedure for detecting unauthorized modification. This series of processing is executed by the ECU 30 (detecting unit 36) when the engine is in a plurality of predetermined operating states.

  First, it is determined whether or not the difference between the first characteristic and the second characteristic of the fuel discharge amount by the fuel pump 41 is larger than a predetermined value (S31). Specifically, with respect to the discharge amount of the fuel pump 41 in a predetermined operation state of the engine, the first characteristic that is the characteristic of the state that has not been tampered with stored in the storage unit 34 and the current characteristic that is acquired by the acquisition unit 35. It is determined whether or not a difference from a certain second characteristic is greater than a predetermined determination value. Note that the amount of fuel discharged by the fuel pump 41 may be calculated based on the driving state of the fuel pump 41, or may be detected by a sensor or the like.

  In the determination of S31, when it is determined that the difference between the first characteristic and the second characteristic of the fuel discharge amount by the fuel pump 41 is not greater than a predetermined value (S31: NO), this series of processes is temporarily terminated (S31: NO). END). On the other hand, when it is determined that there is a cylinder with the difference larger than the predetermined value (S31: YES), it is determined whether the difference is larger than the predetermined value in a plurality of predetermined operation states of the engine (S32).

  In the determination of S32, when it is determined that the difference is larger than a predetermined value in a plurality of predetermined operating states of the engine (S32: YES), after the state where the difference is smaller than the predetermined value is maintained for a predetermined period of time, It is determined whether or not a state in which the difference is greater than a predetermined value has been maintained beyond a predetermined period (S33). As this predetermined period, for example, three engine start times can be employed.

  When it is determined in S32 that the difference is not larger than a predetermined value in a plurality of predetermined operating states (S32: NO), or in S33, the state where the difference is smaller than a predetermined value is maintained over a predetermined period. If it is determined that the above difference is not maintained beyond the predetermined period (S33: NO), it is determined that this change is a change with time (S34). Then, this series of processing is temporarily ended (END).

  On the other hand, in the determination of S33, after the state in which the difference is smaller than the predetermined value is maintained for a predetermined period, and then the state in which the difference is larger than the predetermined value is determined to be maintained for a predetermined period (S33: YES) ), It is detected that this change is due to unauthorized modification (S35). That is, it detects that the fuel injection system has been tampered with. Then, this series of processing is temporarily ended (END).

  This embodiment has the following advantages. Here, only the advantages different from the first embodiment will be described.

  -Even if the current characteristic (second characteristic) of the fuel injection system changes from the characteristic (first characteristic) that has not been tampered with, the second characteristic may temporarily become an abnormal value due to noise, etc. There is sex. In contrast, when the fuel injection system is tampered with, the state is often maintained after the second characteristic deviates from the first characteristic. Therefore, after the state where the difference between the first characteristic and the second characteristic is smaller than the predetermined value is maintained for a predetermined period, the state where the difference between the first characteristic and the second characteristic is larger than the predetermined value exceeds the predetermined period. In this case, it is possible to detect with high accuracy that the fuel injection system has been tampered with.

  If the fuel injection system has been tampered with, the amount of fuel injected may be greater than before the tampering, and the discharge amount of the fuel pump 41 may increase accordingly. Therefore, by using the discharge amount of the fuel pump 41 as the characteristic of the fuel injection system, it is possible to detect that the fuel injection system has been tampered with.

  -When the discharge amount of the fuel pump 41 changes in a plurality of predetermined operating states of the engine, there is a high possibility that an improper modification has been made, not a discharge amount calculation error. Therefore, in the second characteristics in the plurality of predetermined operating states of the engine, when the first characteristics and the second characteristics are different from the predetermined characteristics, it is detected with high accuracy that the tampering with the fuel injection system has been performed. can do.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described focusing on differences from the first embodiment. In the present embodiment, when the first characteristic and the second characteristic of the torque generated by the engine are different from a predetermined value, it is detected that the fuel injection system has been tampered with. The storage unit 34 stores a torque (first characteristic) generated by the engine in a predetermined operating state of the engine at the time of factory shipment (a state in which the tampering is not performed).

  As described in the third embodiment, when the output value (voltage) of the fuel pressure sensor 20 changes due to unauthorized modification, the amount of fuel injected from the fuel injection valve 10 may increase. Therefore, in this embodiment, unauthorized modification is detected as follows.

  FIG. 11 is a flowchart illustrating a processing procedure for unauthorized modification detection. This series of processing is executed by the ECU 30 (detecting unit 36) when the engine is in a predetermined operating state.

  First, it is determined whether or not the difference between the first characteristic and the second characteristic of the torque generated by the engine is greater than a predetermined value (S41). Specifically, with respect to the generated torque of the engine in a predetermined operation state of the engine, the first characteristic that is the characteristic of the state that has not been tampered with stored in the storage unit 34 and the current characteristic that is acquired by the acquisition unit 35. It is determined whether or not the difference from the two characteristics is greater than a predetermined determination value. It should be noted that the torque generated by the engine may be calculated based on the increasing speed of the engine rotational speed, the acceleration of the vehicle, or the like, or may be detected by a torque sensor or the like.

  In the determination of S41, when it is determined that the difference between the first characteristic and the second characteristic of the torque generated by the engine is not greater than a predetermined value (S41: NO), this series of processes is temporarily ended (END). On the other hand, if it is determined that the difference is greater than the predetermined value (S41: YES), it is detected that the difference is due to unauthorized modification (S42). That is, it detects that the fuel injection system has been tampered with. Then, this series of processing is temporarily ended (END).

  This embodiment has the following advantages. Here, only the advantages different from the first embodiment will be described.

  -If the fuel injection system is tampered with, the amount of fuel injected may be greater than before tampering, and the torque generated by the engine may increase accordingly. Therefore, by using the torque generated by the engine as the characteristic of the fuel injection system, it can be detected that the fuel injection system has been tampered with.

  It should be noted that the above-described embodiments can be modified as follows.

  -When an unauthorized modification to the fuel injection system is detected, the driver may be notified of this, or the driver may be warned. In addition, when unauthorized modification is performed on the fuel injection system, the amount of fuel injected is often increased as compared to before the unauthorized modification. On the other hand, when the detection unit 36 detects that the tampering has been performed, a limiting unit 37 that limits the fuel injection amount by the fuel injection system may be provided. Thereby, even if it is a case where unauthorized remodeling is performed, it can suppress that the quantity of the fuel injected increases.

  -If the fuel injection system is tampered with, the characteristics of the fuel injection system often change before and after the tampering. Accordingly, in the plurality of characteristics, it may be detected that the fuel injection system has been tampered with on condition that the first characteristic and the second characteristic are different from a predetermined value. Specifically, the fuel injection system has been tampered with on condition that a plurality of tampering detection processes of the first to fourth embodiments have been executed and it has been detected that tampering has been performed in a plurality of processes. May be finally detected. Thereby, the detection precision of unauthorized modification can be improved.

  As the first characteristic that is the characteristic of the fuel injection system that has not been tampered with, the characteristic at the time of vehicle inspection and the characteristic at the time of design can be used as well as the characteristic at the time of factory shipment.

  When an unauthorized modification is made to the control program of the fuel injection system, for example, the output value (voltage) by the fuel pressure sensor 20 does not change, and the driving state of the fuel injection valve 10 may change. Even in such a case, one of the current characteristics (second characteristic) of the fuel injection system often changes from the characteristic (first characteristic) in a state where the fuel injection system has not been tampered with. Therefore, by selecting an appropriate characteristic as the characteristic of the fuel injection system, it is detected that the fuel injection system has been tampered with when the first characteristic and the second characteristic are different from a predetermined value. be able to.

  An air flow meter, an intake pressure sensor, an exhaust pressure sensor, an air-fuel ratio sensor, an accelerator sensor, a speed meter, a rotation speed sensor, or the like can be used as a sensor for detecting a physical quantity of the fuel injection system. And based on the detection value of those sensors, the 2nd characteristic of a fuel-injection system is acquired, and unauthorized modification can be detected by comparing with the 1st characteristic.

  The above embodiments can be applied not only to the fuel injection system mounted on the engine of the vehicle but also to the fuel injection system mounted on the engine of a ship or the like.

  30 ... ECU, 34 ... storage part, 35 ... acquisition part, 36 ... detection part.

Claims (9)

A storage unit (34) storing a first characteristic that is a characteristic of the fuel injection system that has not been tampered with;
An acquisition unit (35) for acquiring a second characteristic which is a current characteristic of the system;
Detection for detecting that the system has been tampered with when the first characteristic stored in the storage unit and the second characteristic acquired by the acquisition unit are different from a predetermined value. Part (36);
A tampering detection device (30) for a fuel injection system, comprising: Comprising a plurality of sensors (20) for detecting a common physical quantity of the system;
The storage unit stores the first characteristic corresponding to the common physical quantity,
The acquisition unit acquires the second characteristics based on detection values from the plurality of sensors,
The detection unit, when the first characteristic and the second characteristic are different from each other in all the second characteristics acquired based on detection values from the plurality of sensors, The unauthorized modification detection device for a fuel injection system according to claim 1, wherein the unauthorized modification is detected.   The detecting unit maintains a state in which a difference between the first characteristic and the second characteristic is smaller than a predetermined value over a predetermined period, and then a difference between the first characteristic and the second characteristic is larger than a predetermined value. 2. The unauthorized modification detection device for a fuel injection system according to claim 1, wherein when the large state is maintained beyond a predetermined period, it is detected that the system has been modified illegally. The system comprises a fuel pressure sensor (20) for detecting fuel pressure in the system,
The fuel injection system according to any one of claims 1 to 3, wherein the characteristic of the system includes a pre-pressurized fuel pressure detected by the fuel pressure sensor before fuel in the system is pressurized. Tampering detection device. The fuel injection system includes a pressure accumulation container (42) for accumulating and holding fuel, a fuel injection valve (10) for injecting the fuel from an injection hole (11b), and a flow of the fuel from the pressure accumulation container to the injection hole. A fuel passage (42b, 11a) and a predetermined fuel pressure sensor (20) for detecting the fuel pressure in the fuel passage,
The acquisition unit acquires an injection parameter indicating an injection state of the fuel based on the fuel pressure detected by the predetermined fuel pressure sensor when the fuel is injected by the fuel injection valve;
The unauthorized modification detection device for a fuel injection system according to any one of claims 1 to 4, wherein the characteristic of the system includes the injection parameter acquired by the acquisition unit. The system comprises a pump (41) for pumping fuel in the system,
The unauthorized modification detection device for a fuel injection system according to any one of claims 1 to 5, wherein the characteristic of the system includes a discharge amount of the pump. The system is a system for injecting fuel in an internal combustion engine,
The unauthorized modification detection of the fuel injection system according to any one of claims 1 to 6, wherein the characteristic of the system includes a torque generated by the engine due to combustion of fuel injected by the system in the engine. apparatus. The characteristic of the system includes a plurality of characteristics;
8. The system according to claim 1, wherein, in the plurality of characteristics, the system detects that the system has been tampered with on the condition that the first characteristic and the second characteristic are different from a predetermined value. The tampering detection device for the fuel injection system described in 1.   The fuel according to any one of claims 1 to 8, further comprising a limiting unit (37) configured to limit a fuel injection amount by the system when the detection unit detects that the unauthorized modification has been performed. A tamper detection device for the injection system.

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