JP2008182874A - Load-driving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load-driving apparatus which detects +B abnormality on a low side of an electromagnetic coil driving an inhalation metering valve. <P>SOLUTION: When actual current flowing in an electromagnetic coil is acquired (step 100); the acquired actual current exceeds an abnormal current value (step 110), a current deviation ΔI between the actual current and target current is acquired (step 120), the acquired current deviation ΔI becomes not less than an abnormal current deviation value (step 130), and additionally a value of actual current is zero (step 150), +B abnormality on the low side of the electromagnetic coil is decided (step 160). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a load driving device having a function of detecting a power input abnormality on the low side of a load.

2. Description of the Related Art Conventionally, in a diesel fuel injection system, a load driving device that drives an electromagnetic coil of an intake metering valve (SCV) built in an intake metering type fuel supply pump is known (see, for example, Patent Document 1). . In the load driving device, a protection circuit is provided on the low side of the electromagnetic coil as a load. The protection circuit has a function of protecting the electromagnetic coil by stopping the current flowing through the electromagnetic coil when an abnormality occurs in the battery power source that supplies current to the electromagnetic coil. Further, the load driving device has a function of detecting each battery power supply abnormality and ground abnormality of the high side and low side of the electromagnetic coil that drives the intake metering valve.
JP 2003-307149 A

  However, in the above-described conventional technology, when an abnormality occurs in the battery power source or the ground that supplies current to the electromagnetic coil that drives the suction metering valve, the battery power abnormality or the ground abnormality cannot be detected on the low side of the electromagnetic coil. This will be described with reference to FIGS.

  Hereinafter, a battery power supply abnormality, that is, a battery power short circuit is referred to as + B abnormality, and a ground abnormality, that is, a ground short circuit is referred to as a GND abnormality. 5 to 7, the current flowing through the electromagnetic coil is described as an SCV actual current, and the target current to be flowed through the electromagnetic coil is described as an SCV target current.

  FIG. 5 is a time chart of the current flowing through the electromagnetic coil when + B is abnormal on the high side of the electromagnetic coil. FIG. 6 is a time chart of the current flowing through the electromagnetic coil at the time of + B abnormality on the low side of the electromagnetic coil. FIG. 7 shows a time chart of the current flowing through the electromagnetic coil when the ground current of the current flowing through the electromagnetic coil is abnormal.

  First, when the actual current flowing through the electromagnetic coil exceeds the + B abnormal current threshold value indicating that the actual current flowing through the electromagnetic coil exceeds a certain time, the load driving device determines that it is + B abnormal and determines the diagnosis of + B abnormality. Further, when the actual current flowing through the electromagnetic coil is below a GND abnormal current threshold value indicating that the ground current is abnormal for a certain period of time, the load driving device determines that there is a GND abnormality and determines the diagnosis of the GND abnormality.

  As shown in FIG. 5, the actual current flowing through the high side of the electromagnetic coil increases more rapidly than the target current flowing through the electromagnetic coil when + B abnormality occurs on the high side of the electromagnetic coil, and exceeds the + B abnormal current threshold. However, the actual current flowing through the electromagnetic coil does not continue to increase due to the effect of the resistance of the electromagnetic coil, and the actual current exceeding the + B abnormal current threshold continues for a certain time.

  For this reason, the load driving device can determine that the actual current flowing through the high side of the electromagnetic coil exceeds the + B abnormal current threshold, and can determine that it is + B abnormal. Accordingly, a diagnosis indicating the + B abnormality can be determined, and the high-side + B abnormality of the electromagnetic coil that drives the suction metering valve is normally determined to be the high-side + B abnormality of the electromagnetic coil. Can be determined.

  In the above case, since the + B abnormality is determined before the GND abnormality is determined, even if the actual current flowing through the electromagnetic coil falls below the GND abnormal current threshold, the diagnosis indicating the GND abnormality is not made.

  However, for the low side of the electromagnetic coil, when the actual current flowing through the electromagnetic coil exceeds the + B abnormal current threshold, the protection circuit is activated and no current flows through the electromagnetic coil. For this reason, as shown in FIG. 6, the actual current flowing through the low side of the electromagnetic coil increases more rapidly than the target current flowing through the electromagnetic coil when + B abnormality occurs on the low side of the electromagnetic coil. The flowing current becomes zero. As a result, the time when the actual current exceeds the + B abnormal current threshold becomes shorter than the time during which it can be determined that the load driving device is + B abnormal.

  Therefore, before the load driving device is determined to be + B abnormal, the actual current suddenly decreases and falls below the GND abnormal current threshold, and the load driving device determines that the GND is abnormal and performs diagnosis as a GND abnormality. .

  In addition, as shown in FIG. 7, when an abnormality occurs in the ground of the electromagnetic coil, the current flowing through the electromagnetic coil falls below the GND abnormal current threshold before the target current, and diagnosis is determined as a GND abnormality.

  When the suction metering valve is not driven due to the occurrence of + B abnormality or GND abnormality, the actual pressure in the common rail as the pressure accumulating vessel gradually increases with respect to a certain target pressure, but the load drive device abnormality There is no impact on judgment.

  As described above, the conventional load driving device can normally detect + B abnormality on the high side of the electromagnetic coil that drives the suction metering valve, while the low side abnormality detection of the electromagnetic coil is detected as + B abnormality while being + B abnormality. The diagnosis has been finalized. In such a case, when repairing the load driving device, it is necessary to check from the GND abnormality not related to the failure, and the repair becomes complicated.

  Thus, it is conceivable to provide a detection circuit only for detecting + B abnormality on the low side of the electromagnetic coil 90, but this is not preferable because the cost increases.

  An object of the present invention is to provide a load driving device that can detect a low-side + B abnormality of an electromagnetic coil that drives an intake metering valve.

  In order to achieve the above object, according to the first feature of the present invention, first, the current flowing through the actual current detection resistor (60) connected to the load (90) is detected by the differential amplifier circuit section (70). Thus, the drive current flowing through the load is acquired, and it is determined whether or not the drive current flowing through the load is greater than or equal to an abnormal current value estimated to be a short circuit of the battery power supply on the low side of the load. In addition, a current deviation which is a difference between a drive current flowing through the load and a target current to be passed through the load stored in the storage means (85) is acquired, and the current deviation is a current based on a short circuit of the battery power supply on the low side of the load. It is determined whether or not the value is equal to or greater than the abnormal current deviation value estimated to be the deviation value. If the drive current flowing through the load is greater than or equal to the abnormal current value and the current deviation is greater than or equal to the abnormal current deviation value, the battery power source on the low side of the load is assumed to be abnormal. It is characterized in that a diagnosis is confirmed to be informed that the short is short.

  Thereby, the behavior of + B abnormality on the low side of the load can be determined one by one, and a short circuit of the battery power source on the low side of the load can be determined. Therefore, it is possible to normally determine that the battery power supply is short-circuited without determining that a short circuit of the battery power supply on the low side of the load is a ground short.

  Accordingly, even when a failure due to a short circuit occurs in the load driving device, it is not necessary to check from a ground short circuit unrelated to the failure, and the repair process can be reduced. Further, by performing the determination as described above, a circuit only for detecting a short circuit of the battery power source on the low side of the load can be eliminated.

  As described above, it is possible to notify that the short circuit of the battery power supply on the low side of the load is not the ground short circuit but the short circuit of the battery power supply.

  Further, after determining that the drive current flowing through the load by the control means is greater than or equal to the abnormal current value, and determining that the current deviation is greater than or equal to the abnormal current deviation value, it is determined whether or not current is flowing through the load. If it is determined that no current flows through the load, the diagnosis can be confirmed.

  In the second feature of the present invention, first, the current flowing through the actual current detection resistor (60) connected to the load (90) is detected by the differential amplifier circuit section (70), whereby the drive current flowing through the load is detected. , And whether or not the drive current flowing through the load is equal to or greater than an abnormal current value estimated to be a short circuit of the battery power supply on the low side of the load. Moreover, while acquiring the pressure in an accumulator, the rail pressure deviation which is the difference of the pressure in the said accumulator and the target pressure in the accumulator memorize | stored in the memory | storage means (85) is acquired, and rail pressure deviation Is determined to be greater than or equal to an abnormal rail pressure deviation value estimated to be a value based on a short circuit of the battery power supply on the low side of the load. When the drive current flowing through the load is equal to or greater than the abnormal current value and the rail pressure deviation is equal to or greater than the abnormal rail pressure deviation value, it is assumed that an abnormality has occurred in the battery power source on the low side of the load. It is characterized in that a diagnosis is confirmed and notified that the battery power supply is short-circuited.

  Thus, based on the behavior of the pressure in the pressure accumulator when the short circuit of the battery power source occurs on the low side of the load, it is possible to determine whether the battery power source is short on the low side of the load. Even in this case, it is possible to notify that the short-circuit of the battery power supply on the low side of the load is not a ground short-circuit but a short-circuit of the battery power supply.

  In the third feature of the present invention, it is also possible to determine that an abnormality has occurred in the battery power source on the low side of the load by a combination of the first feature of the present invention and the second feature of the present invention.

  That is, the drive current flowing through the load (90) is acquired to determine whether the drive current is equal to or greater than the abnormal current value, and the current deviation is acquired to determine whether the current deviation is equal to or greater than the abnormal current deviation value. If the drive current is equal to or greater than the abnormal current value and the current deviation is equal to or greater than the abnormal current deviation value, the battery power supply may be abnormal on the low side of the load. The content is retained as an abnormality. Further, the pressure in the pressure accumulator is acquired to acquire a rail pressure deviation that is the difference between the pressure and the target pressure, and it is determined whether or not the rail pressure deviation is equal to or greater than the abnormal rail pressure deviation value. If the temporary abnormality is maintained and the rail pressure deviation is equal to or greater than the abnormal rail pressure deviation value, it is assumed that an abnormality has occurred in the battery power supply on the low side of the load, and the battery power supply is short on the low side of the load. It is characterized by performing a diagnosis confirmation and informing.

  As described above, by determining whether the battery power supply is short on the low side of the load based on both the drive current flowing through the load and the pressure in the accumulator, it is possible to accurately determine whether the battery power supply is short-circuited.

  In the load driving device shown above, a protection circuit (4, 5, 6, 50) that cuts off an overcurrent when an overcurrent flows through the load can be provided on the low side of the load.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The load driving device shown in the present embodiment drives an intake metering valve that changes a pumping amount pumped from a supply pump in a vehicle into a common rail by an electromagnetic coil.

  FIG. 1 is a block diagram of a load driving apparatus according to the first embodiment of the present invention. As shown in this figure, the load driving device 1 includes an overcurrent detection resistor 10, a current detection circuit unit 20, a level conversion unit 30, a drive transistor 40, a protection transistor 50, and an actual current detection resistor. 60, a differential amplifier circuit unit 70, a CPU 80, and a storage unit 85.

  The overcurrent detection resistor 10 is a resistor for detecting an overcurrent flowing through the electromagnetic coil 90 that drives the suction metering valve (SCV) connected to the load driving device 1. One end of the overcurrent detection resistor 10 is connected to the battery power source 2, and the other end is connected to the drain of the driving transistor 40. Hereinafter, the battery power source 2 is referred to as + B.

  The current detection circuit unit 20 detects an overcurrent flowing through the overcurrent detection resistor 10, and when the overcurrent flows through the overcurrent detection resistor 10, issues a drive stop command for causing the level conversion unit 30 to stop the driving transistor 40. It has a function to put out.

  The level conversion unit 30 PWM-drives the driving transistor 40 by inputting a PWM signal as a gate voltage corresponding to the driving signal input from the CPU 80 to the driving transistor 40 via the resistor 3. The level conversion unit 30 stops driving of the driving transistor 40 based on a driving stop command input from the current detection circuit unit 20.

  The driving transistor 40 is a Pch-type transistor that causes a current to flow through the electromagnetic coil 90 connected to the load driving device 1 by turning on / off based on the PWM signal input from the level conversion unit 30. In the present embodiment, the source of the driving transistor 40 is connected to the high side of the electromagnetic coil 90. The resistor 3, the level conversion unit 30, and the driving transistor 40 correspond to the driving means of the present invention.

  The protection transistor 50 is an Nch transistor that cuts off the current flowing through the electromagnetic coil 90 as a load based on a command from the CPU 80 when + B abnormality or GND abnormality occurs, and functions as a protection circuit. . In the present embodiment, the drain of the protection transistor 50 is connected to the low side of the electromagnetic coil 90.

  The electromagnetic coil 90 corresponds to the load of the present invention. Further, in the following description, it is assumed that the + B abnormality means a short circuit of the battery power supply 2 and the GND abnormality means a ground short circuit. The high side of the electromagnetic coil 90 refers to the high voltage side of the electromagnetic coil 90, and an electrical path between the terminal to which the source of the driving transistor 40 is connected and one end of the electromagnetic coil 90 in the load driving device 1. It corresponds to. The low side of the electromagnetic coil 90 indicates the low voltage side of the electromagnetic coil 90 and corresponds to an electrical path between the terminal to which the drain of the protection transistor 50 is connected in the load driving device 1 and the other end of the electromagnetic coil 90. Each of these paths is a wiring such as a wire harness. The + B abnormality on the high side of the electromagnetic coil 90 means that the high side of the electromagnetic coil 90 is + B short-circuited. In the load driving device 1, a terminal to which the source of the driving transistor 40 is connected and one end of the electromagnetic coil 90. This means that the wiring between and has the same potential as + B. The + B abnormality on the low side of the electromagnetic coil 90 means that the low side of the electromagnetic coil 90 is shorted by + B, and between the terminal to which the drain of the protection transistor 50 is connected in the load driving device 1 and the other end of the electromagnetic coil 90. This means that the wiring of the same potential as + B. The GND abnormality of the electromagnetic coil 90 means a ground short as described above, but more specifically indicates that the high side or the low side of the electromagnetic coil 90 is shorted to the ground.

  The gate of the protection transistor 50 is connected to one end of the resistor 4, and the other end of the resistor 4 is connected to one end of the resistor 5 and the collector of the npn-type stop transistor 6. The emitter of the stopping transistor 6 is connected to the ground, and a voltage of 5 V is applied to the other end of the resistor 5. The resistors 4 and 5, the stop transistor 6, and the protection transistor 50 correspond to the protection circuit of the present invention.

  The base of the stop transistor 6 is connected to the CPU 80. The base is driven in accordance with a protection signal input from the CPU 80, so that the protection transistor 50 is driven and the current flowing through the electromagnetic coil 90 is cut.

  The actual current detection resistor 60 is a resistor for detecting a drive current flowing through the electromagnetic coil 90, and one end is connected to the source of the protection transistor 50 and the other end is connected to the ground.

  The differential amplifier circuit section 70 amplifies the current flowing through the actual current detection resistor 60 and A / D converts it into the CPU 80.

  The CPU 80 has a function of inputting a drive signal to the level conversion unit 30 to drive the drive transistor 40, and a function of inputting a protection signal to the stop transistor 6 in order to drive the protection transistor 50 to function as a protection circuit. The function of executing + B abnormality detection processing for detecting + B abnormality on the low side of the electromagnetic coil 90 based on the current flowing through the electromagnetic coil 90 input from the differential amplifier circuit unit 70 is provided. The CPU 80 corresponds to the control means of the present invention.

  The storage unit 85 is a storage unit that stores data, and includes a ROM, a RAM, and the like. The storage unit 85 stores a + B abnormality detection program for the CPU 80 to execute + B abnormality detection processing, a target current value to be passed through the electromagnetic coil 90, and the like. The program is executed by the CPU 80.

  The above is the overall configuration of the load driving device 1 according to the present embodiment. For example, an ECU is employed as the load driving device 1.

  In the load driving device 1, when a GND abnormality occurs, the current flowing through the actual current detection resistor 60 becomes zero. For this reason, the CPU 80 determines that the current has fallen below the GND abnormal current threshold, and the diagnosis is confirmed as a high-side or low-side GND abnormality.

  When + B abnormality occurs on the high side of the electromagnetic coil 90, the current after flowing through the electromagnetic coil 90 flows through the actual current detection resistor 60. Therefore, it can be determined that the current flowing through the actual current detection resistor 60 exceeds the + B abnormal current threshold until the protection transistor 50 as the protection circuit is activated, and + B abnormality on the high side of the electromagnetic coil 90 is detected. Can be detected.

  In the load driving device 1, the protection transistor 50 functioning as a protection circuit is driven as follows. Normally, when the electromagnetic coil 90 is driven, a protection signal for turning off the base of the stopping transistor 6 is input from the CPU 80. As a result, the stop transistor 6 is turned off, and a constant voltage is input to the connection point of the resistors 4 and 5, that is, the gate of the protection transistor 50, and the protection transistor 50 is turned on. As a result, a current flows through the electromagnetic coil 90 and the suction metering valve is driven.

  However, when + B abnormality occurs on the low side of the electromagnetic coil 90, the current flowing through the actual current detection resistor 60 increases rapidly (see FIG. 6), and the current value is detected and A / D converted by the differential amplifier circuit unit 70. And input to the CPU 80. As a result, a protection signal for turning on the base of the stop transistor 6 is input from the CPU 80, the stop transistor 6 is turned on, a current flows through the resistor 5, and the gate of the protection transistor 50 is turned off. Then, no current flows through the actual current detection resistor 60, and the load driving device 1 detects that the GND is abnormal.

  Next, in order to prevent the load driving device 1 from erroneously determining as a GND abnormality in spite of the occurrence of + B abnormality on the low side of the electromagnetic coil 90 as described above, the load driving device 1 causes the low side of the electromagnetic coil 90 to The + B abnormality detection process for detecting + B abnormality will be described with reference to FIG. FIG. 2 is a flowchart showing the contents of the + B abnormality detection program for detecting the low-side + B abnormality of the electromagnetic coil 90. In the present embodiment, when power is supplied to the load driving device 1, the flow shown in FIG. 2 starts according to the + B abnormality detection program. Further, the flow is repeatedly executed at a constant cycle while the load driving device 1 is operating.

  In step 100, the current flowing through the electromagnetic coil 90 is acquired. This is obtained by amplifying and A / D converting the current flowing through the actual current detection resistor 60 shown in FIG.

  In step 110, it is determined whether or not the actual current flowing through the electromagnetic coil 90 is equal to or greater than the abnormal current value. The abnormal current value is a value that is estimated to be a short circuit of the battery power source 2 on the low side of the electromagnetic coil 90 that is a load, and is stored in the storage unit 85.

  If it is determined in this step that the actual current is less than the abnormal current value, this flow ends, assuming that + B abnormality has not occurred on the low side of the electromagnetic coil 90, and starts again after a predetermined time has elapsed. If it is determined in this step that the actual current is greater than or equal to the abnormal current value, the process proceeds to step 120.

  In step 120, the current deviation ΔI is obtained. This is acquired by calculating the difference between the actual current acquired in step 100 and the target current to be passed through the electromagnetic coil 90 stored in the storage unit 85.

  In step 130, it is determined whether or not the absolute value of the current deviation ΔI is greater than or equal to the abnormal current deviation value. The abnormal current deviation value is a value estimated that the absolute value of the current deviation ΔI when the electromagnetic coil 90 is normally driven is abnormal, and is stored in the storage unit 85. The current deviation ΔI becomes a small value when a current normally flows through the electromagnetic coil 90, and becomes a large value when an actual current stops flowing when the protection transistor 50 as the protection circuit is driven.

  If it is determined in this step that the absolute value of the current deviation ΔI is less than the abnormal current deviation value, this flow ends, assuming that no + B abnormality has occurred on the low side of the electromagnetic coil 90, and the flow shown in FIG. 2 is repeated. Executed. If it is determined in this step that the absolute value of the current deviation ΔI is greater than or equal to the abnormal current deviation value, the process proceeds to step 140.

  In step 140, it is determined in step 130 whether or not it has been determined n times consecutively that the absolute value of the current deviation ΔI is equal to or greater than the abnormal current deviation value. This step is provided in order to reliably determine whether the determination result in step 130 is caused by + B abnormality. For example, n is set to 2. In this step, if it is not determined that n times are continuous, the process returns to step 120. If it is determined in this step that the sequence is n times, the process proceeds to step 150.

  In step 150, it is determined whether or not the value of the actual current flowing through the electromagnetic coil 90 is zero. That is, when an abnormal current flows through the electromagnetic coil 90, as described above, the stop transistor 6 is turned on by the protection signal from the CPU 80, and the protection transistor 50 as a protection circuit is turned off. As a result, as shown in FIG. 6, the actual current increases rapidly due to the + B abnormality, but rapidly decreases due to the protection transistor 50 being turned off, and no current flows through the electromagnetic coil 90.

  Therefore, if the current normally flows through the electromagnetic coil 90, the protection transistor 50 is not driven and a current flows through the electromagnetic coil 90. Therefore, it is determined that the actual current is not 0, and the process returns to step 120. On the other hand, if the protection transistor 50 is driven so that no current flows through the electromagnetic coil 90, a real current of 0 is acquired in step 100, so that the real current is determined to be 0 in this step. The process proceeds to step 160.

  In step 160, a diagnosis of + B abnormality on the low side of the electromagnetic coil 90 is determined. Thus, this throw ends.

  As described above, in the present embodiment, the actual current flowing through the electromagnetic coil 90 is acquired, the acquired actual current exceeds the abnormal current value, and the current deviation ΔI between the actual current and the target current is acquired and acquired. If the current deviation ΔI is equal to or greater than the abnormal current deviation value and the actual current value is 0, it is characterized that the low-side + B abnormality of the electromagnetic coil 90 is determined.

  In this manner, by determining the behavior of the + B abnormality on the low side of the electromagnetic coil 90 shown in FIG. 6 one by one, it is possible to detect the + B abnormality on the low side of the electromagnetic coil 90. Accordingly, it is possible to determine a diagnosis indicating that the abnormality is + B without diagnosing the low-side abnormality of the electromagnetic coil 90 as the GND abnormality.

  In such a case, when the load driving device 1 is repaired, it is no longer necessary to check for a GND abnormality that is not related to the failure, and the repair can be prevented from being complicated. Further, it is not necessary to provide a detection circuit only for detecting + B abnormality on the low side of the electromagnetic coil 90, and the cost can be reduced.

(Second Embodiment)
In the present embodiment, only different parts from the first embodiment will be described. In the first embodiment, + B abnormality on the low side of the electromagnetic coil 90 is detected based on the current flowing through the electromagnetic coil 90. In this embodiment, + B on the low side of the electromagnetic coil 90 is detected based on the pressure in the common rail. It is characterized by detecting abnormalities.

  That is, in the load driving device 1 shown in FIG. 1, a signal corresponding to the pressure is constantly input from a pressure sensor (not shown) that detects the pressure in the common rail, and is stored in the storage unit 85 as an actual pressure. Yes. The storage unit 85 also stores a target rail pressure in the common rail.

  FIG. 3 is a flowchart showing the contents of the + B abnormality detection program for detecting the low-side + B abnormality of the electromagnetic coil 90 in the present embodiment. First, in step 200, the current flowing through the electromagnetic coil 90 is acquired as in step 100 above.

  In step 210, as in step 110, it is determined whether or not the actual current flowing through the electromagnetic coil 90 is equal to or greater than the abnormal current value. If it is determined in this step that the actual current is less than the abnormal current value, this flow ends, assuming that no + B abnormality has occurred on the low side of the electromagnetic coil 90. If it is determined in this step that the actual current is greater than or equal to the abnormal current value, the process proceeds to step 220.

  In step 220, a delay process is performed. As shown in FIG. 6, when the protection transistor 50 operates and the electromagnetic coil 90 is not driven, the current in the common rail rises after the current stops flowing through the electromagnetic coil 90. Therefore, a delay is provided in this step until the actual pressure starts to gradually increase in order to obtain the rail pressure deviation ΔPC in step 230 thereafter.

  In step 230, the rail pressure deviation ΔPC is acquired. This is acquired by calculating the difference between the actual pressure in the common rail input from the pressure sensor and the target rail pressure stored in the storage unit 85.

  In step 240, it is determined whether or not the absolute value of the rail pressure deviation ΔPC is greater than or equal to the abnormal rail pressure deviation value. The abnormal rail pressure deviation value is a value estimated that the absolute value of the rail pressure deviation ΔPC, which is the difference between the pressure in the common rail and the target rail pressure when the electromagnetic coil 90 is normally driven, is abnormal. And is stored in the storage unit 85.

  If it is determined in this step that the absolute value of the rail pressure deviation ΔPC is less than the abnormal rail pressure deviation value, this flow is terminated assuming that no + B abnormality has occurred on the low side of the electromagnetic coil 90. If it is determined in this step that the absolute value of the rail pressure deviation ΔPC is greater than or equal to the abnormal rail pressure deviation value, the process proceeds to step 250.

  In step 250, it is determined in step 240 whether or not the absolute value of the rail pressure deviation ΔPC has been continuously determined n times as being equal to or greater than the abnormal rail pressure deviation value. In this step, for example, n is 2. If it is not determined in this step that it is n times continuous, the process returns to step 230. If it is determined in this step that the sequence is n times, the process proceeds to step 260.

  In step 260, as in step 160, a diagnosis of + B abnormality on the low side of the electromagnetic coil 90 is determined. Thus, this throw ends.

  As described above, in the present embodiment, the actual current flowing through the electromagnetic coil 90 is acquired, the acquired actual current exceeds the abnormal current value, and the rail pressure deviation ΔPC between the actual pressure in the common rail and the target rail pressure is obtained. When the acquired rail pressure deviation ΔPC is equal to or greater than the abnormal rail pressure deviation value, it is characterized in that it is determined that the + B abnormality is present on the low side of the electromagnetic coil 90.

  As described above, when the + B abnormality occurs on the low side of the electromagnetic coil 90, the protection transistor 50 is activated and the electromagnetic coil 90 is not driven, and the pressure in the common rail is increased. A + B abnormality on the low side of the coil 90 can be determined. In this way, the diagnosis of the low-side + B abnormality of the electromagnetic coil 90 can be determined as a + B abnormality.

(Third embodiment)
In the present embodiment, only different portions from the above embodiments will be described. This embodiment is characterized in that the low-side + B abnormality of the electromagnetic coil 90 is determined by combining the first and second embodiments. In the following, the process illustrated in FIG. 2 in the first embodiment is referred to as a first abnormality detection process, and the process illustrated in FIG. 3 in the second embodiment is referred to as a second abnormality detection process.

  FIG. 4 is a flowchart showing the content of the + B abnormality detection program for detecting the low-side + B abnormality of the electromagnetic coil 90 in the present embodiment. In the flow shown in FIG. 4, first, a first abnormality detection process is performed. The first abnormality detection process is a process corresponding to each of steps 100 to 150 shown in FIG.

  That is, the current flowing through the electromagnetic coil 90 is acquired at step 300, and it is determined at step 305 whether the actual current flowing through the electromagnetic coil 90 is equal to or greater than the abnormal current value. If it is determined that the actual current is greater than or equal to the abnormal current value, a current deviation ΔI is acquired at step 310. If it is determined in step 305 that the actual current does not exceed the abnormal current value, this flow ends.

  Subsequently, at step 315, it is determined whether or not the absolute value of the current deviation ΔI is greater than or equal to the abnormal current deviation value. If it is determined that the absolute value of the current deviation ΔI is less than the abnormal current deviation value, this flow ends, assuming that no + B abnormality has occurred on the low side of the electromagnetic coil 90. If it is determined in step 315 that the absolute value of the current deviation ΔI is greater than or equal to the abnormal current deviation value, the process proceeds to step 320.

  In step 320, if it is determined in step 315 that the absolute value of ΔI is continuously greater than or equal to the abnormal current deviation value, the process proceeds to step 325, and if other determination results, the process returns to step 310.

  In step 330, the result that the + B provisional abnormality is present on the low side of the electromagnetic coil 90 is held.

  Subsequent to step 330, a second abnormality detection process is performed. The second abnormality detection process is a process corresponding to each of steps 230 to 260 shown in FIG. First, at step 335, the rail pressure deviation ΔPC is acquired, and at step 340, it is determined whether or not the absolute value of the rail pressure deviation ΔPC is greater than or equal to the abnormal rail pressure deviation value. If it is determined in step 340 that the absolute value of the rail pressure deviation ΔPC is greater than or equal to the abnormal rail pressure deviation value, the process proceeds to step 345, and in the case of other determination results, this flow ends.

  Then, in step 345, it is determined whether or not it has been determined n times continuously that the absolute value of the rail pressure deviation ΔPC is equal to or greater than the abnormal rail pressure deviation value. If it is determined in the step 345 that it is continuous n times, the process proceeds to step 350, and in the case of other determination results, this flow ends.

  In step 350, as in steps 160 and 260, a diagnosis of + B abnormality on the low side of the electromagnetic coil 90 is determined. Thus, this throw ends.

  As described above, the present embodiment is characterized in that the low-side + B abnormality of the electromagnetic coil 90 is determined by combining the first and second abnormality detection processes in the first and second embodiments. Thus, + B abnormality determination can be performed based on the actual current flowing through the electromagnetic coil 90 and the actual pressure in the common rail. In such a case, since the + B abnormality is determined using different parameters, the accuracy of the determination can be improved.

(Other embodiments)
The circuit of the load driving device 1 shown in FIG. 1 shows an example, and other circuit forms may be adopted.

  The flowcharts shown in FIGS. 2 to 4 show an example, and the present invention is not limited to this. For example, in the first embodiment, in the flow shown in FIG. 1, it is determined in step 140 whether the absolute value of the current deviation ΔI is equal to or more than the abnormal current deviation value n times continuously. It can be a lost flow. The step 140 is a step for increasing the certainty of the determination of the + B abnormality. If the certainty of the determination can be ensured in another step, the process may proceed from the step 130 to the step 150. The same applies to step 250 in the second embodiment. Moreover, it is good also as a flow which eliminated step 150 and step 250, respectively.

  Note that the steps shown in each figure correspond to means for realizing the function, and each step of the flowcharts shown in FIGS. 2 to 4 can be configured as hardware.

1 is a block diagram of a load driving device according to a first embodiment of the present invention. In 1st Embodiment, it is a flowchart which shows the content of the + B abnormality detection program which detects + B abnormality of the low side of an electromagnetic coil. In 2nd Embodiment, it is a flowchart which shows the content of the + B abnormality detection program which detects + B abnormality of the low side of an electromagnetic coil. In 3rd Embodiment, it is a flowchart which shows the content of the + B abnormality detection program which detects + B abnormality of the low side of an electromagnetic coil. It is a time chart of the electric current which flows into an electromagnetic coil at the time of + B abnormality of the high side of the electromagnetic coil driven by the load drive device conventionally. It is the time chart of the electric current which flows into an electromagnetic coil at the time of + B abnormality of the low side of the electromagnetic coil driven by the load drive device conventionally. It is the time chart of the electric current which flows into an electromagnetic coil at the time of the ground abnormality of the electric current which flows in the electromagnetic coil driven by the load drive device conventionally.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Load drive device, 2 ... Battery power supply, 10 ... Overcurrent detection resistor, 20 ... Current detection circuit part, 30 ... Level conversion part, 40 ... Drive transistor, 50 ... Protection transistor, 60 ... Real current detection resistor, 70: differential amplifier circuit unit, 80: CPU, 85: storage unit, 90: electromagnetic coil

Claims (6)

Driving means (3, 30, 40) for driving the load (90);
A load drive device comprising a control means (80) for driving the drive means so that a drive current flows from the battery power source (2) to the load,
The control means includes
Means (100) for obtaining a drive current flowing through the load by detecting a current flowing through the actual current detection resistor (60) connected to the load by the differential amplifier circuit section (70);
Means (110) for determining whether or not the drive current flowing through the load is equal to or greater than an abnormal current value estimated to be a short circuit of the battery power supply on the low side of the load;
Means (120) for obtaining a current deviation which is a difference between a drive current flowing through the load and a target current to be passed through the load stored in a storage means (85);
Means (130) for determining whether or not the current deviation is equal to or greater than an abnormal current deviation value estimated to be a value of a current deviation based on a short circuit of the battery power supply on the low side of the load;
When the drive current flowing through the load is equal to or greater than the abnormal current value and the current deviation is equal to or greater than the abnormal current deviation value, it is determined that an abnormality has occurred in the battery power source on the low side of the load. A load driving device comprising means (160) for confirming and notifying that the battery power supply is short on the low side. The control means determines that the drive current flowing through the load is greater than or equal to the abnormal current value, and determines whether or not current is flowing through the load after determining that the current deviation is greater than or equal to the abnormal current deviation value. The load driving device according to claim 1, further comprising a determination unit (150) configured to determine the diagnosis when it is determined that no current flows through the load. Driving means (3, 30, 40) for driving the load (90);
A load drive device comprising a control means (80) for driving the drive means so that a drive current flows from the battery power source (2) to the load and pumping high-pressure fuel to the accumulator,
The control means includes
Means (200) for obtaining a drive current flowing through the load by detecting a current flowing through the actual current detection resistor (60) connected to the load by the differential amplifier circuit section (70);
Means (210) for determining whether or not the drive current flowing through the load is equal to or greater than an abnormal current value estimated to be a short circuit of the battery power supply on the low side of the load;
Means (230) for obtaining a pressure in the accumulator and obtaining a rail pressure deviation which is a difference between the pressure in the accumulator and the target pressure in the accumulator stored in the storage means (85). When,
Means (240) for determining whether or not the rail pressure deviation is equal to or greater than an abnormal rail pressure deviation value estimated to be a value based on a short circuit of the battery power supply on the low side of the load;
When the drive current flowing through the load is equal to or greater than the abnormal current value and the rail pressure deviation is equal to or greater than the abnormal rail pressure deviation value, an abnormality has occurred in the battery power source on the low side of the load. A load driving device comprising: means (260) for confirming and notifying that the battery power supply is short-circuited on the low side of the load. Driving means (3, 30, 40) for driving the load (90);
A load drive device comprising a control means (80) for driving the drive means so that a drive current flows from the battery power source (2) to the load and pumping high-pressure fuel to the accumulator,
The control means includes
Means (300) for obtaining a drive current flowing through the load by detecting a current flowing through the actual current detection resistor (60) connected to the load by the differential amplifier circuit section (70);
Means (305) for determining whether or not the drive current flowing through the load is equal to or greater than an abnormal current value estimated to be a short circuit of the battery power supply on the low side of the load;
Means (310) for obtaining a current deviation which is a difference between a drive current flowing through the load and a target current to be passed through the load stored in a storage means (85);
Means (315) for determining whether or not the current deviation is equal to or greater than an abnormal current deviation value estimated to be a value of a current deviation based on a short circuit of the battery power supply on the low side of the load;
When the drive current flowing through the load is equal to or greater than the abnormal current value and the current deviation is equal to or greater than the abnormal current deviation value, there is a possibility that an abnormality has occurred in the battery power source on the low side of the load. Means (330) for retaining the content as a temporary abnormality,
Means (335) for acquiring the pressure in the pressure accumulator and obtaining a rail pressure deviation which is the difference between the pressure in the pressure accumulator and the target pressure in the pressure accumulator stored in the storage means (85). When,
Means (340) for determining whether or not the rail pressure deviation is equal to or greater than an abnormal rail pressure deviation value estimated to be a value based on a short circuit of the battery power supply on the low side of the load;
When the temporary abnormality is maintained and the rail pressure deviation is equal to or greater than the abnormal rail pressure deviation value, it is determined that an abnormality has occurred in the battery power source on the low side of the load, and the battery on the low side of the load Means (350) for confirming and notifying that the power supply is short-circuited, is provided. The control means determines that the drive current flowing through the load is greater than or equal to the abnormal current value, and determines whether or not current is flowing through the load after determining that the current deviation is greater than or equal to the abnormal current deviation value. 5. The load drive according to claim 4, further comprising a determination unit (325) configured to hold the content as the temporary abnormality when it is determined that no current flows through the load. apparatus. The low side of the load is provided with a protection circuit (4, 5, 6, 50) that cuts off the overcurrent when an overcurrent flows through the load. The load drive apparatus as described in any one.

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