JP5066227B2 - Internal combustion engine control device - Google Patents

Description

  The present invention relates to an internal combustion engine control device for automobiles, motorcycles, agricultural machinery, industrial machinery, marine aircraft, etc., which uses gasoline, light oil or the like as fuel, and in particular, a fuel injection device driven by a battery voltage or a boosted battery voltage. The present invention relates to an electromagnetic load control device, etc., its drive and fault diagnosis.

  For internal combustion engine control devices such as automobiles, motorcycles, agricultural machinery, industrial machinery, and marine aircraft that use gasoline or light oil as fuel, an injector that directly injects fuel into the cylinder (fuel injection) for the purpose of improving fuel efficiency and output. Device). Such an in-cylinder direct injection type injector uses a high pressure fuel, and therefore requires a lot of energy for the valve opening operation. Further, in order to cope with improvement in control performance (responsiveness) and high-speed rotation (high-speed control), it is necessary to shorten the supply time and interruption time of the energy to the injector. That is, it is necessary to cut off the electromagnetic load current flowing through the electromagnetic load in a short time. As an example of a prior art of an internal combustion engine control device that controls fuel injection, there is one disclosed in Patent Document 1.

  In order to cut off the electromagnetic load current in a short time and move (consume) a large amount of the above-mentioned energy accumulated in the electromagnetic load from the electromagnetic load, for example, heat energy using the Zener diode effect in the drive circuit, for example A method of converting to devise has been devised. In addition, a method of regenerating energy stored in an electromagnetic load in a booster circuit as described in Patent Document 2 has been proposed. In this method, there is a method of regenerating by using a regenerative element such as a current regenerative diode, and the heat generation of the drive circuit through which a large current flows can be relatively reduced. Therefore, even in a direct injection engine using gasoline as a fuel, in use.

  If an electromagnetic load has a fault (a power fault, a ground fault, a short circuit, or an open circuit) while the electromagnetic load is being driven or stopped, it is necessary to immediately detect and diagnose the fault. However, in the conventional internal combustion engine control device, when the drive cycle is shortened (that is, when the rotational speed of the internal combustion engine is increased), failure detection timing control cannot be set well, and the diagnostic circuit, for example, drives Although the circuit and the electromagnetic load are normal, there may be a misdiagnosis that a power fault has occurred. In addition, since it took a long time to return the potential of the diagnostic region to the initial state, it may be an obstacle to improving the control performance. In addition, the diagnostic circuit may make a wrong diagnosis due to sudden disturbance such as noise.

  Further, when the regenerative element is destroyed by being applied with energy exceeding a specified level, the regenerative element cannot regenerate energy, which may lead to a serious accident such as heat generation of the device and ignition.

Japanese Patent No. 3711168 JP 2001-234793 A

  The present invention relates to an internal combustion engine control device that drives an electromagnetic load such as an injector (fuel injection device), even when the rotational speed of the internal combustion engine increases, that is, even when the driving cycle of the electromagnetic load decreases. The purpose is to improve the load fault diagnosis accuracy and to stably perform high-speed control. In addition, it aims at providing the internal combustion engine control apparatus which is not influenced by noise.

  Further, in the internal combustion engine control apparatus having a battery voltage booster circuit, a highly reliable fault diagnosis is performed even for a circuit that causes the booster circuit to regenerate back electromotive energy generated when the electromagnetic load is driven. Objective.

  A feature of the present invention is that a current source or a voltage source for adjusting the potential of a diagnostic part is provided in order to ensure high failure diagnosis accuracy even when the drive cycle of an electromagnetic load such as a fuel injection device in an internal combustion engine is shortened. There is. In addition, in order to ensure diagnosis accuracy that is not affected by sudden disturbance such as noise, the diagnosis timing is optimally set and the number of determinations for averaging is increased.

  Further, for the failure diagnosis of the circuit to be regenerated by the booster circuit, the above-described object can be achieved by detecting the input / output voltage or regenerative current of the driving switch element of the electromagnetic load.

Specifically, the configuration of the electromagnetic load control device according to the present invention is basically as follows.
For an electromagnetic load, a power source for the electromagnetic load, and a driver disposed at least between the power source and the electromagnetic load and between the electromagnetic load and a power ground for driving the electromagnetic load In an electromagnetic load control device comprising a switching element and a diagnostic means for diagnosing a fault in a circuit configuration by detecting a voltage abnormality between the electromagnetic load and the switching element, back electromotive energy generated when the electromagnetic load is interrupted At least one of means for rapidly attenuating, means for setting a time zone for detecting the voltage abnormality, and means for obtaining confirmation of the voltage abnormality is provided.

  In an internal combustion engine control apparatus that drives an electromagnetic load, the reliability and accuracy of failure diagnosis of the electromagnetic load can be ensured even when the drive cycle of the internal combustion engine is shortened. In addition, fault diagnosis that is not affected by noise can be guaranteed. Furthermore, since the failure diagnosis of the circuit that regenerates the back electromotive energy to the booster circuit can be performed reliably, the improvement in safety can be expected as compared with the conventional case.

1 is a circuit configuration diagram of an internal combustion engine controller according to Embodiment 1 of the present invention. FIG. It is a circuit block diagram of the internal combustion engine control apparatus of Example 2 by this invention. It is a figure which shows an example of the operation waveform of the circuit in the internal combustion engine control apparatus of Example 1. FIG. It is a circuit block diagram of the internal combustion engine control apparatus of Example 3 by this invention. It is a figure which shows an example of the operation waveform of the circuit in the internal combustion engine control apparatus of Example 3. It is a circuit block diagram of the internal combustion engine control apparatus of Example 4 by this invention. It is a figure which shows an example of the operation waveform of the circuit in the internal combustion engine control apparatus of Example 4. It is a circuit block diagram of the internal combustion engine control apparatus of Example 5 by this invention. FIG. 10 is a diagram illustrating an example of operation waveforms of a circuit in an internal combustion engine control apparatus according to a fifth embodiment. It is a circuit block diagram of the internal combustion engine control apparatus of Example 6 by this invention. It is a figure which shows an example of the operation waveform of the circuit in the internal combustion engine control apparatus of Example 6. It is a circuit block diagram of the internal combustion engine control apparatus of Example 7 by this invention. FIG. 10 is a diagram illustrating an example of operation waveforms of a circuit in an internal combustion engine control apparatus according to a seventh embodiment. It is a circuit block diagram of the internal combustion engine control apparatus of Example 8 by this invention. It is a circuit block diagram of the internal combustion engine control apparatus of Example 9 by this invention. It is a figure which shows an example of the operation waveform of the circuit in the internal combustion engine control apparatus of Example 8. It is a figure which shows an example of the operation waveform of the circuit in the internal combustion engine control apparatus of Example 9. In Example 1, it is a figure which shows the circuit structure in which the 1st electric current amount adjustment circuit 18 is not provided for the comparison. In Example 1, it is a figure which shows an example of the operation waveform in the circuit of the structure by which the 1st electric current amount adjustment circuit 18 is not provided.

  An embodiment of an internal combustion engine controller according to the present invention will be described below.

  A first embodiment of an internal combustion engine control apparatus according to the present invention will be described with reference to FIGS.

  FIG. 1 shows a circuit configuration of the internal combustion engine control device 2, which includes a battery voltage 1, a booster circuit 3 that boosts the battery voltage 1, and an electromagnetic load 5 that is installed between the booster circuit 3 and a power supply ground 37.

  The internal combustion engine controller 2 also includes switch elements (for example, FETs) constituting a driver for an electromagnetic load on the battery voltage side and the power supply ground 37 side as viewed from the electromagnetic load 5, that is, the high-side driver 4 and the low-side driver 4. A side driver 10 is installed. Here, the battery voltage side as viewed from the electromagnetic load 5 is referred to as a high side (upstream), and the power ground 37 side is referred to as a low side (downstream).

  Further, the internal combustion engine control device 2 includes a microprocessor 30, a logic circuit 31, a drive signal generation circuit 28 for a high side driver, and a drive signal generation circuit 12 for a low side driver. In addition, a voltage detection circuit 15 and a diagnosis circuit 25 are provided for failure diagnosis of the electromagnetic load 5.

  The booster circuit 3 boosts the battery voltage 1 and this boosted voltage is applied to the electromagnetic load 5 via the high-side driver 4 and the low-side driver 10. With this boosted voltage, the current 5A flowing through the electromagnetic load 5 such as an injector is raised in a short time. That is, the internal combustion engine control device 2 drives the electromagnetic load 5 by driving the high-side driver 4 and the low-side driver 10. This process will be described below. A control signal 29 output from the microprocessor 30 is input to the logic circuit 31. Based on this control signal, the logic circuit 31 outputs a logic high-side driver drive signal 26 and a low-side driver drive signal 13 to the analog drive signal generation circuits 28 and 12, respectively. The drive signal generation circuits 28 and 12 generate an analog high side driver drive signal 27 and a low side driver drive signal 11 based on the input logic signals 26 and 13. By the analog drive signals 27 and 11, the high side driver 4 and the low side driver 10 are energized (turned on), the electromagnetic load current 5A flows through the electromagnetic load 5, and the electromagnetic load 5 is driven.

  The electromagnetic load current 5A is a relatively large current required to drive (for example, open) a valve body of the electromagnetic load 5 such as an injector with good response. After the electromagnetic load 5 is driven, a current sufficient to maintain the state of the driven valve body is supplied to the electromagnetic load 5 for a predetermined time as follows. In this case, the low-side driver drive signal remains on (that is, the low-side driver 10 is on), while the high-side driver drive signal is off (the high-side driver 4 is off), and further chopping is performed. The electromagnetic load 5 is chopped via the drive signal generation circuit 108, and the state after the electromagnetic load 5 is driven is maintained. The chopping drive signal 109 is output from the logic circuit 31 based on the control signal 29 from the microprocessor 30. Details of this will be described later with reference to FIG.

  The diagnosis circuit 25 performs failure diagnosis of the electromagnetic load 5. The voltage detection circuit 15 detects the drain voltage 46 of the low-side driver 10 and outputs a diagnostic flag signal 14 to the diagnostic circuit 25.

  For example, when the drain voltage 46 of the low-side driver 10 rises and reaches a voltage close to the battery voltage 1, that is, if the low-side driver drain voltage 46 exceeds the threshold for detecting the power fault, the diagnostic circuit 25 A power fault diagnosis is made that the load 5 has a power fault.

  On the other hand, when the drain voltage 46 of the low-side driver 10 decreases to reach the ground level voltage, that is, when the low-side driver drain voltage 46 is below the ground fault detection threshold, the diagnostic circuit 25 Make a ground fault diagnosis that 5 has a ground fault.

  Further, the internal combustion engine control device 2 includes a first current amount adjustment circuit 18, a second current amount adjustment circuit 20, and a current adjustment drive signal changeover switch 111. The first current amount adjustment circuit 18 includes a first current source 17. The second current amount adjustment circuit 20 includes a second current source 19 and a third current source 21. The change-over switch 111 is used to selectively switch the current sources 17, 19, and 21 of the first and second current amount adjustment circuits (18, 20) in accordance with the output signal of the drain voltage detection circuit 15. is there.

  Among them, the second current amount adjusting circuit 20 detects the drain voltage on the switching element (low side driver 10) side of the electromagnetic load, and keeps the drain voltage at the time of driving the electromagnetic load at a predetermined voltage level. . For example, when the drain voltage is low, the third current source (power source side current source) 21 is turned on via the drain voltage detection circuit 15 and the current adjustment drive signal changeover switch 111 to increase the drain voltage. When the drain voltage is high, the second current source (ground side current source) 19 is turned on to decrease the drain voltage, and finally the drain voltage is kept at a constant level. In this case, the second current source 19 is connected to the ground side, but is designed to gently lower the drain voltage in order to converge the drain voltage to a predetermined level.

  On the other hand, the first current source 17 used in the first current amount adjusting circuit 18 is when the energization of the electromagnetic load 5 is cut off (when not driven: when the high-side and low-side drivers 4 and 10 are turned off). It plays a role of rapidly attenuating a jumping voltage due to back electromotive energy generated on the drain side of the low-side driver 10 by an electromagnetic load. As a result, the rapid decay of the back electromotive energy prevents a power fault from being erroneously diagnosed at the timing when the voltage detection circuit 15 detects a power fault and a ground fault. By the way, the timing for performing the operation for detecting the power supply fault and the ground fault is when the control signal 29 from the microprocessor 30 rises, that is, when the electromagnetic load 5 starts driving (when the high side and low side drivers 4 and 10 are turned on). At the beginning). Details of this will be described later with reference to the timing charts of FIGS.

  The first current source 17 used for the first current amount adjustment circuit 18 is connected between the drain side of the low-side driver 10 and the ground, similarly to the second current source 19 used for the second current amount adjustment circuit 20. There are the following differences. That is, the second current source 19 is a convergence sink current source for converging the drain voltage to a predetermined level, whereas the first current source 17 is for rapid counter-electromotive energy decay (rapid drain voltage rapid decay). The specifications are different.

  The internal combustion engine control device 2 also includes a noise / surge protection capacitor (upstream) 7 and a noise / surge protection capacitor 7 in order to protect the input signal and output signal of the electromagnetic load 5 from disturbances such as external surges and noise. A surge protection capacitor (downstream) 9 is provided.

  Furthermore, the internal combustion engine control device 2 includes a backflow prevention diode 6 and a current regeneration diode 8. The backflow prevention diode 6 prevents a backflow of current during chopping control of the electromagnetic load 5. The current regeneration diode 8 causes the booster circuit 3 to regenerate a regenerative current due to the back electromotive energy of the low side driver 10 when the low side driver drive signal (analog) 11 is turned off at the fall of the control signal 29. .

  Next, the operation of the first embodiment will be described with reference to the timing chart of FIG.

  When the control signal 29 output from the microprocessor 30 is turned on, the driving signals for the low-side driver 10 and the high-side driver 4, that is, the low-side driver driving signal (analog) 11 and the high-side driver driving signal (analog) 27 are turned on. Thus, the electromagnetic load current 5 A flows through the electromagnetic load 5.

The electromagnetic load current 5A rises in a short time to the peak current threshold 100 during the peak current energization period in the initial energization by the battery voltage 1 boosted by the booster circuit 3. The peak current threshold 100 is a value for stopping the current and is determined in advance. The electromagnetic load current 5A that has reached the peak current threshold 100 transitions to the holding section, and is chopped by the chopping drive signal generation circuit 108 after the high-side driver 4 is turned off (the high-side current 81A is turned off).
The waveform of the electromagnetic load upstream voltage 103 at this time is as shown in FIG. When the operation of the electromagnetic load is completed, the electromagnetic load current 5A is rapidly cut off in a short energization current falling period in order to quickly return the electromagnetic load to the initial state.

  When the control signal 29 is turned off, the low side driver drive signal (analog) 11 is turned off at the falling edge of the control signal 29. Back electromotive energy is generated by the electromagnetic load 5 on the drain side of the low side driver 10 at the falling timing 39 of the low side driver drive signal 11 (gate signal). The low-side driver drain voltage 46 jumps to a specific voltage (bounce voltage 300) due to this counter-electromotive energy. The jump voltage 300 is stored in the noise / surge protection capacitor (downstream) 9. At the same time, the jump voltage 300 is input to the voltage detection circuit 15 as the low side driver drain voltage 46. Then, the first current amount adjusting circuit 18 and the second current amount adjusting circuit 20 are controlled by the current adjusting drive signal changeover switch 111 according to the detection result of the voltage detection circuit 15.

  At this time, as shown in FIG. 3, when the low-side driver drain voltage 46 is higher than the power fault threshold 104, the first current source control signal 16 is output high from the current adjustment drive signal changeover switch 111, and the first current Source 17 is turned on. As a result, the low-side driver drain voltage 46 can discharge the charge accumulated in the noise / surge protection capacitor (downstream) 9 and can rapidly attenuate the jumping voltage 300. When the low side driver drain voltage 46 becomes equal to or lower than the power supply threshold 104, the first current source control signal 16 becomes a low output by the current adjustment drive signal changeover switch 111, and the first current source 17 is turned off. At the fall timing 33 of the first current source control signal, the second current source control signal 24 is output high from the current adjustment drive signal changeover switch 111, and the second current source 19 is turned on. As a result, the low-side driver drain voltage 46 rapidly decays but does not decrease too much, converges to a constant value 105, and reaches a steady state.

  The timing for diagnosing whether or not the power supply is in the state of power is adjusted to the rising edge of the control signal 29. Except for the rise of the control signal 29, the electromagnetic load 5 is rapidly raised or back electromotive energy is generated, so that it is difficult to determine the power fault. If the low-side driver drain voltage 46 exceeds the power-failure threshold 104 at the power-failure detection timing 116, it is determined that the power-supply state is in effect.

  According to the present embodiment, even if the low side driver drain voltage 46 jumps to a specific voltage due to the back electromotive force and is charged to the noise / surge protection capacitor 9, the charged voltage until the power fault detection timing 116 is reached. Can be attenuated rapidly.

  Therefore, even when the rotation speed of the internal combustion engine increases and the drive cycle of the control signal 29 is shortened and the interval of the power supply detection timing 116 is narrowed, the power supply circuit and the electromagnetic load are normal, but the power supply is not damaged. The electromagnetic load 5 can be diagnosed with high accuracy and controlled at a high speed without making a false diagnosis of occurrence.

  Further, according to the above method, the current from the first current source 17 can flow only when the low-side driver drain voltage 46 jumps up to a specific voltage due to the back electromotive energy, thereby reducing heat generation. There is also an advantage that you can.

  Of the first and second current amount adjusting circuits 18 and 20, the first current amount adjusting circuit 18 (first current source 17) is not provided, and the second current amount adjusting circuit 20 (second In the configuration in which only the current source 19 and the third current source 21) are provided, that is, in the configuration as shown in the comparison diagram of FIG. 18, the reverse electromotive energy rapid decay (rapid drain voltage rapid decay) as described above is performed. I can't expect. In FIG. 18, the same reference numerals as those in the first embodiment denote the same or common elements as those in the first embodiment. That is, in the state of FIG. 18, even if the electromagnetic load 5 is deenergized, even if the drain voltage detection circuit 15 detects the jumped drain voltage and turns on the second current source 19, the second current source No. 19 cannot rapidly discharge the voltage due to the back electromotive energy charged in the noise / surge protection capacitor 9 due to its specifications. Accordingly, as indicated by reference numeral 300 in the timing chart shown in FIG. 19, the back electromotive energy jumps to a predetermined drain voltage while drawing a gentle attenuation curve.

  In this case, when the number of revolutions of the internal combustion engine increases and the drive cycle of the control signal 29 is shortened, and the interval of the power fault detection timing 116 is narrowed, the drain voltage of the counter electromotive energy becomes the power fault detection threshold value. When the value does not fall below, the power supply detection timing 116 is entered, and the possibility of erroneous diagnosis that a power supply fault has occurred even though the drive circuit and the electromagnetic load are normal increases.

  FIG. 2 illustrates a second embodiment of the internal combustion engine controller according to the present invention.

  In the configuration of this embodiment, the first current source 17 shown in FIG. 1 is changed to a first current source resistor 32. The first current source resistor 32 serves as a sink current resistor. Since the low-side driver drain voltage 46 charged in the noise / surge protection capacitor 9 is consumed and discharged by the first current source resistor 32, it is rapidly attenuated as in the first embodiment shown in FIG. be able to. Therefore, even with such a configuration, it is possible to obtain the same effect as in the first embodiment.

  A third embodiment of the internal combustion engine control apparatus according to the present invention will be described with reference to FIGS.

  As shown in FIG. 4, the configuration of this embodiment is obtained by changing the positions of the diagnostic circuit 25 and its peripheral circuits from downstream to upstream of the electromagnetic load 5 in Embodiment 1 (FIG. 1). The peripheral circuit includes a first current amount adjustment circuit 18, a second current amount adjustment circuit 20, a voltage detection circuit 15, and a current adjustment drive signal changeover switch 111. In the first embodiment, the failure diagnosis of the electromagnetic load 5 is performed by detecting the low side driver drain voltage 46. The failure diagnosis of the electromagnetic load 5 in this embodiment is performed by detecting the high side driver drain voltage 114 (the drain voltage of the high side driver) with the voltage detection circuit 15 and diagnosing with the diagnosis circuit 25.

  The operation in this embodiment is shown in the timing chart of FIG. The high side driver drain voltage 114 rises to the jumping voltage 300 due to the back electromotive energy at the high side driver gate signal falling timing 48. At this time, the first current source control signal 16 is output high from the current adjustment drive signal changeover switch 111, the first current source 17 is turned on, and the high-side driver drain voltage 114 is rapidly attenuated. Then, the high-side driver drain voltage 114 becomes equal to or lower than the power supply threshold 104, the first current source control signal 16 becomes a low output, and the first current source 17 is turned off. On the other hand, at the falling timing 33 of the first current source control signal, the second current source control signal 24 is output high from the current adjustment drive signal changeover switch 111, and here, the second current source 19 is turned on. As a result, the high-side driver drain voltage 114 converges to a constant value 106.

  As described above, the operation in the present embodiment is almost the same as that in the first embodiment except that the low side driver drain voltage 46 is replaced by the high side driver drain voltage 114. Therefore, even in the configuration of the present embodiment, as in the first embodiment, even when the rotational speed of the internal combustion engine is increased and the drive cycle of the control signal 29 is shortened and the interval of the power supply detection timing 116 is narrowed, the drive is performed. It is possible to diagnose the electromagnetic load 5 with high accuracy and control it at a high speed without making a misdiagnosis that a power fault occurs even though the circuit and the electromagnetic load are normal.

  A fourth embodiment of the internal combustion engine controller according to the present invention will be described with reference to FIGS. Examples 1 to 3 are examples of a device that can prevent misdiagnosis in the detection of a power fault among power and ground fault detection, but in this embodiment, an example of a device that can prevent a misdiagnosis by ground fault detection It is.

  As shown in FIG. 6, the internal combustion engine control device 2 in this embodiment is a noise / surge protection capacitor (downstream from the electromagnetic load 5 in the internal combustion engine control device 2 of the third embodiment shown in FIG. (Downstream) 9, the low side driver 10, and the drive signal generation circuit 12 for the low side driver are omitted.

  The logic circuit 31 receives the control signal 29 output from the microprocessor 30 and outputs a high-side driver drive signal (logic) 26 to the drive signal generation circuit 28 for the high-side driver. The drive signal generation circuit 28 for the high side driver that has received the high side driver drive signal (logic) 26 outputs the high side driver drive signal (analog) 27 to the high side driver 4. The high-side driver 4 is driven by a high-side driver drive signal (analog) 27 and causes an electromagnetic load current 5 </ b> A to flow through the electromagnetic load 5. The failure diagnosis of the electromagnetic load 5 is performed by the diagnosis circuit 25 after the source voltage 115 of the high side driver 4 is detected by the voltage detection circuit 15.

  The operation in this embodiment will be described with reference to the timing chart of FIG.

  When the control signal 29 from the microprocessor 30 is turned on, the drive signal for the high side driver 4, that is, the high side driver drive signal (analog) 27 is turned on, and the electromagnetic load current 5 A flows through the electromagnetic load 5.

  When the control signal 29 is turned off, the gate signal of the high side driver 4 is turned off. At the high-side driver gate signal falling timing 48, the source voltage 115 of the high-side driver 4 drops to a specific voltage (drop voltage 302) due to the back electromotive energy. Due to the drop voltage 302, the charge of the noise / surge protection capacitor (upstream) 7 is discharged and reduced. At the same time, the drop voltage 302 is input to the voltage detection circuit 15 as the high side driver source voltage 115. Then, the first current amount adjusting circuit 18 and the second current amount adjusting circuit 20 are controlled by the current adjusting drive signal changeover switch 111 according to the detection result of the voltage detection circuit 15.

  At this time, if the high-side driver source voltage 115 is lower than the ground fault threshold 44, the first current source control signal 16 is output high from the current adjustment drive signal changeover switch 111, and the first current source 17 is turned on. As a result, the high side driver source voltage 115 rises rapidly as shown in FIG. When the high-side driver source voltage 115 becomes equal to or higher than the ground fault threshold 44, the first current source control signal 16 becomes a low output and the first current source 17 is turned off. At the fall timing 33 of the first current source control signal, the second current source control signal 24 is output high from the current adjustment drive signal changeover switch 111, and the third current source 21 is turned on. As a result, the high-side driver source voltage 115 converges to a constant voltage value 107.

  The timing for diagnosing whether or not it is a ground fault condition is matched with the rising edge of the control signal 29 in the same manner as the diagnosis of the power fault condition in the first embodiment. If the high-side driver source voltage 115 is lower than the ground fault threshold 44 at this ground fault detection timing, it is determined that a ground fault state has occurred.

  However, even if the high-side driver source voltage 115 drops to a specific voltage due to the back electromotive energy and the noise / surge protection capacitor 7 is discharged by the operation as described above, the discharged voltage is detected before the ground fault detection timing. Can be increased rapidly.

  Therefore, even when the rotation speed of the internal combustion engine increases and the drive cycle of the control signal 29 is shortened and the interval of the ground fault detection timing is narrowed, the ground fault occurs even though the drive circuit and the electromagnetic load are normal. Therefore, the electromagnetic load 5 can be diagnosed with high accuracy and controlled at a high speed.

  A fifth embodiment of the internal combustion engine controller according to the present invention will be described with reference to FIGS.

  The internal combustion engine control device 2 of the present embodiment has a circuit configuration similar to that of the first embodiment, but differs in the following points. In this embodiment, the current regeneration diode 8 and the chopping drive signal generation circuit 108 shown in FIG. 1 are omitted (however, the current regeneration diode 8 and the chopping drive signal generation circuit 108 may be provided), and the filter time shown below is used. A generation circuit 50, a diagnostic window generation circuit 58, and a delay time variable circuit 301 are included.

  The filter time generation circuit 50 provides a predetermined delay time to the low-side driver drive signal (logic) 13 and becomes high or low with a delay from the rise or fall of the control signal 29. The delay time is a time that does not hinder high-speed operation of the internal combustion engine provided with the internal combustion engine control device 2. The low-side driver drive signal (logic) 13 provided with the delay time, that is, the delayed low-side driver drive signal (logic) 13a is input to the drive signal generation circuit 12 for the low-side driver. For this reason, a delay time equivalent to the delay time also occurs between the control signal 29 and the low-side driver drive signal (analog) 11. During this delay time, even if the control signal 29 is input, the control of the electromagnetic load current 5A is not started, so that the potential level fluctuation of the low side driver drain voltage 46 does not occur.

  The delay time generated by the filter time generation circuit 50 is input to the diagnostic window generation circuit 58. A diagnostic window signal 112 is output from the diagnostic window generation circuit 58 during the delay time and is input to the diagnostic circuit 25. The diagnostic circuit 25 operates while the diagnostic window signal 112 is on. When the low-side driver drain voltage 46 exceeds the power fault threshold or the ground fault threshold, the diagnostic circuit 25 counts the exceeded time. .

  FIG. 9 shows a timing chart when a disturbance such as noise is mixed in the low-side driver drain voltage 46 with respect to the internal combustion engine control apparatus 2 having the above circuit configuration. Diagnosis of the power supply fault or ground fault of the electromagnetic load 5 is started by using the rising timing 51 of the control signal 29 as a trigger, and is performed in synchronization with the rising edge of the clock signal while the diagnostic window signal 112 is on. The diagnostic window signal 112 is turned on at the rising timing 51 of the control signal 29 and turned off at the rising timing 53 of the low-side driver drive signal (analog) 11. The low side driver drive signal (analog) 11 is delayed by a delay time 56 from the rising timing 51 of the control signal 29. That is, the diagnostic window signal 112 is on during the delay time 56.

  While the diagnostic window signal 112 is on, the diagnostic counter of the diagnostic circuit 25 counts the time when the low-side driver drain voltage 46 exceeds the power fault threshold or falls below the ground fault threshold as described above. Diagnose sky and ground faults. In this diagnosis, when the number of times the diagnosis counter is counted up is less than a predetermined diagnosis count, the diagnosis flag signal 14 is not output. The diagnostic count number can be determined in advance to be equal to the number of times the clock signal rises during the delay time 56, for example.

FIG. 9 illustrates a case where the low-side driver drain voltage 46 rises due to noise or the like. It is assumed that the diagnostic count number is predetermined as 12 times.
As shown in FIG. 9, the low-side driver drain voltage 46 has a potential fluctuation 113 due to noise or the like. The diagnostic counter counts up from the initial state 54 in synchronization with the rising edge of the clock signal while the low-side driver drain voltage 46 exceeds the power fault threshold 104. In FIG. 9, the count-up (1) 74 and the count-up (2) 55 are counted up twice. Since the count-up number is smaller than the diagnosis count number, the diagnosis flag signal 14 is not output. For this reason, since the potential fluctuation 113 due to noise is not diagnosed as a power fault, no erroneous diagnosis occurs.

  If the count-up number is equal to or greater than the predetermined diagnosis count number (12 times in this embodiment), the diagnostic flag signal 14 is output at the rising timing 53 of the low-side driver drive signal (analog) 11. Turns on and diagnoses that a skylight has occurred.

  The case where the low side driver drain voltage 46 is increased due to noise or the like has been described above. Similarly, when the low-side driver drain voltage 46 drops, while the diagnostic window signal 112 is on, a diagnosis of a ground fault is made by comparing the count-up number with the diagnostic count number. Can be prevented. By the above-described method, it is possible to prevent erroneous diagnosis that a power fault or a ground fault has occurred in the electromagnetic load 5 due to a sudden disturbance such as noise.

  Further, as shown in FIG. 8, the internal combustion engine control apparatus 2 of the present embodiment has the delay time variable circuit 301, so that the delay time 56 can be changed, and the diagnosis flag signal 14 is changed by changing the diagnosis count number. You can also change the conditions to turn on. Therefore, by changing the delay time 56 and the diagnostic count number, there is an advantage that the occurrence of erroneous diagnosis can be prevented even under various conditions.

  A sixth embodiment of the internal combustion engine controller according to the present invention will be described with reference to FIGS. The present embodiment is an example of an internal combustion engine control device that can detect a breakdown or an open state of a current regeneration diode.

  The internal combustion engine control device 2 of the present embodiment has a circuit configuration similar to that of the first embodiment, but differs in the following points. In this embodiment, the regenerative chopping drive signal generation circuit 108 shown in FIG. 1 is omitted (the chopping drive signal generation circuit 108 may be provided), the active clamp circuit 61 shown below is provided, and voltage detection is performed. The circuit 15 detects the gate signal 11 of the low side driver 10.

  When the low-side driver drain voltage 46 exceeds a predetermined value, the active clamp circuit 61 supplies a current to the gate of the low-side driver 10 to forcibly set the gate signal high and turn the low-side driver 10 on. To do.

  The diagnostic circuit 25 receives the diagnostic flag signal 14 from the voltage detection circuit 15 and the low-side driver drive signal (logic) 13 from the logic circuit 31, and compares the two signals to thereby obtain the current regeneration diode 8. Detects the destruction or open state of

  With reference to FIG. 11, the case where the current regeneration diode 8 is broken or opened will be described. It is assumed that the current regenerative diode 8 is broken or opened during the current regenerative diode breaking / opening time 62. Normally, the low side driver drain voltage 46 is raised to the boosted voltage value 63 by the current regeneration diode 8. However, when the current regenerative diode 8 is destroyed or opened, the back electromotive energy cannot be regenerated to the booster circuit 3 during the current regenerative diode destruction / release time 62, so the low side driver drain voltage 46 is It rises beyond the value 63. When the low side driver drain voltage 46 exceeds a predetermined current regeneration diode breakdown detection threshold (2) 70, the active clamp circuit 61 is turned on. Then, current is supplied from the drain of the low-side driver 10 to the gate, and the low-side driver drive signal (analog) 11, that is, the gate signal of the low-side driver 10 is forcibly raised at least during a filter time 65 described later. . As a result, the low-side driver 10 is turned on, and the back electromotive energy that has jumped up is clamped to the clamp voltage value 64.

  Here, a method of detecting the destruction or open state of the current regeneration diode 8 will be described.

  The back electromotive energy that has jumped up is clamped at the clamp voltage value 64. At this time, the potential of the gate signal rises as described above. The voltage detection circuit 15 detects the potential of the gate signal, and outputs a diagnostic flag signal 14 at a high level when a predetermined current regeneration diode breakdown detection threshold (1) 66 is exceeded. The time from when the gate signal is forcibly raised to when the diagnostic flag signal 14 is output high is called a filter time 65.

  On the other hand, as shown in FIG. 11, when the gate signal is forcibly raised by the active clamp circuit 61, the control signal 29 is always low. Therefore, the low side driver drive signal (logic) 13 controlled by the control signal 29 is always low.

  Accordingly, the diagnostic circuit 25 detects a state in which the diagnostic flag signal 14 is high and the low-side driver drive signal (logic) 13 is low. This is a state in which floating of the gate signal occurs during the filter time 65 in spite of the control signal of the low-side driver 10 being low. This means that the active clamp circuit 61 is operating and the current regeneration diode 8 is in a broken or open state. As described above, it can be detected with high accuracy that the current regenerative diode 8 is broken or opened.

  Furthermore, in order to guarantee high detection accuracy even when a disturbance such as noise occurs in the gate of the low side driver 10, the current regeneration diode 8 of the current regeneration diode 8 is within the filter time 65 from the fall of the low side driver drive signal (analog) 11. The state is detected.

  A seventh embodiment of the internal combustion engine controller according to the present invention will be described with reference to FIGS. The present embodiment is another example of the internal combustion engine control device that can detect the destruction or the open state of the current regeneration diode. As a detection method, the voltage of the gate signal of the low-side driver 10 is used in the sixth embodiment, but the drain voltage 46 of the low-side driver 10 is used in this embodiment. The operations of the first and second current amount adjusting circuits 18 and 20 and the current regeneration diode 8 are the same as in the first embodiment.

  FIG. 12 is a diagram showing a circuit of the internal combustion engine control device 2 in the present embodiment. The difference from the sixth embodiment is that the drain voltage 46 of the low-side driver 10 is input to the voltage detection circuit 15. The timing chart shown in FIG. 13 is the same as that of the sixth embodiment.

  As described in the sixth embodiment, when the current regenerative diode 8 is destroyed or opened, the back electromotive energy is applied to the booster circuit 3 during the current regenerative diode breaking / opening time 62 as shown in FIG. I can't regenerate. Therefore, the low-side driver drain voltage 46 exceeds the current regeneration diode breakdown detection threshold (2) 70 and jumps up to the clamp voltage value 64.

  Here, a method for detecting that the current regeneration diode 8 is broken or opened in this embodiment will be described. The jumped low side driver drain voltage 46 is detected by the voltage detection circuit 15. When the current regeneration diode breakdown detection threshold (2) 70 is exceeded, a diagnostic flag signal 14 is output to the diagnostic circuit 25. The diagnostic circuit 25 outputs the diagnostic flag signal 14 high. Thereby, it can be detected that the current regeneration diode 8 is broken or opened.

  In addition, even when a disturbance such as noise occurs in the gate of the low-side driver 10, the detection is performed within the filter time 65 from the fall of the low-side driver drive signal (analog) 11 in order to ensure high detection accuracy.

  If the above method is adopted, it can be detected with higher accuracy that the current regenerative diode 8 is broken or opened.

  An eighth embodiment of the internal combustion engine controller according to the present invention will be described with reference to FIGS. The present embodiment is another example of the internal combustion engine control device that can detect the destruction or the open state of the current regeneration diode. As a detection method, in this embodiment, the presence or absence of a reverse current of a current (hereinafter referred to as a high side current) flowing between the booster circuit 3 and the high side driver 4 is examined.

  FIG. 14 is a diagram showing a circuit of the internal combustion engine control device 2 in the present embodiment. The difference from the seventh embodiment is that a current detection resistor 81 and a current detection circuit 80 are provided between the booster circuit 3 and the high side driver 4, and the current detected by the current detection circuit 80 is input to the voltage detection circuit 15. is there. The first current amount adjustment circuit 18, the second current amount adjustment circuit 20, the first current source 17, the second current source 19, the third current source 21, and the current adjustment drive signal changeover switch 111 are not shown. . The timing chart shown in FIG. 16 is the same as that of the seventh embodiment, but the waveform of the high-side current 81A flowing through the current detection resistor 81 is added.

  As described in the sixth and seventh embodiments, when the current regenerative diode 8 is broken or opened, as shown in FIG. 16, the back electromotive energy is increased during the current regenerative diode breaking / opening time 62 as shown in FIG. Cannot regenerate to 3. Therefore, the low-side driver drain voltage 46 exceeds the current regeneration diode breakdown detection threshold (2) 70 and jumps up to the clamp voltage value 64.

  Here, a method for detecting that the current regeneration diode 8 is broken or opened in this embodiment will be described. As shown in FIG. 16, when the control signal 29 is turned on and the low-side driver drive signal (analog) 11 is turned on, the high-side current 81A flows from upstream to downstream and has a waveform like a peak current 84. Indicates. When the low side driver drive signal (analog) 11 is turned off, normally, a regenerative current flows through the current regenerative diode 8, and the high side current 81 </ b> A flowing through the current detection resistor 81 becomes a reverse current 85.

  However, when the current regenerative diode 8 is broken or opened, the regenerative current cannot flow, and therefore the reverse current 85 does not flow through the current detection resistor 81. In the waveform of the high-side current 81A shown in FIG. 16, the dotted line portion indicates the reverse current 85 that should flow when the current regeneration diode 8 is normal. By detecting by the current detection circuit 80 that the reverse current 85 does not flow, it can be detected that the current regenerative diode 8 is in a broken or open state.

  A ninth embodiment of the internal combustion engine controller according to the present invention will be described with reference to FIGS. The present embodiment is another example of the internal combustion engine control device that can detect the destruction or the open state of the current regeneration diode. As a detection method, in this embodiment, the presence or absence of a regenerative current is examined.

FIG. 15 shows an internal combustion engine control apparatus according to this embodiment. The internal combustion engine control device 2 is the same as that of the eighth embodiment shown in FIG. 14, but the installation position of the current detection circuit 80 and the current detection resistor 81 is changed, and the current regeneration diode 8 and the low side driver 10 are arranged. It was installed in.
A regenerative current 81B flows through the current detection resistor 81. The timing chart shown in FIG. 17 is the same as that of the eighth embodiment, but the waveform of the regenerative current 81B is shown instead of the high side current 81A.

  As described in the eighth embodiment, when the low-side driver drive signal (analog) 11 is turned off, the regenerative current 81B normally flows through the current regenerative diode 8 and also flows through the current detection resistor 81.

  However, when the current regenerative diode 8 is broken or opened, the regenerative current 81B does not flow through the current detection resistor 81. Of the waveform of the regenerative current 81B shown in FIG. 17, the dotted line portion indicates the regenerative current that should flow when the current regenerative diode 8 is normal. By detecting by the current detection circuit 80 that the regenerative current 81B does not flow, it can be detected that the current regenerative diode 8 is in a broken or open state.

  The present invention relates to an internal combustion engine control for driving an electromagnetic load such as a fuel injection device by a battery voltage or a boosted battery voltage in an automobile, a motorcycle, an agricultural machine, an industrial machine, a marine machine, etc. using gasoline or light oil as fuel. Relates to the device. In addition, the control device that changes the driving cycle, such as an internal combustion engine, is applied to a device that requires high diagnostic performance.

  DESCRIPTION OF SYMBOLS 1 ... Battery voltage, 2 ... Internal combustion engine control device, 3 ... Boost circuit, 4 ... High side driver, 5 ... Electromagnetic load, 5A ... Electromagnetic load current, 6 ... Backflow prevention diode, 7 ... Noise / surge protection capacitor (upstream) , 8... Current regeneration diode, 9... Noise / surge protection capacitor (downstream), 10... Low side driver, 11... Low side driver drive signal (analog), 12. ... low side driver drive signal (logic), 13a ... delayed low side driver drive signal (logic), 14 ... diagnostic flag signal, 15 ... voltage detection circuit, 16 ... first current source control signal, 17 ... first current source, DESCRIPTION OF SYMBOLS 18 ... 1st electric current amount adjustment circuit, 19 ... 2nd current source, 20 ... 2nd electric current amount adjustment circuit, 21 ... 3rd current source, 24 ... 2nd current source control signal, 2 Diagnostic circuit, 26 High side driver drive signal (logic), 27 High side driver drive signal (analog), 28 High side driver drive signal generation circuit, 29 Control signal, 30 Microprocessor, 31 Logic circuit 32... First current source resistor 33. First current source control signal falling timing 37. Power supply ground 39. Low side driver gate signal falling timing 44. Ground fault threshold 46. Driver drain voltage, 48... High side driver gate signal fall timing, 50... Filter time generation circuit, 51... Control signal rise timing, 53 .. Low side driver drive signal rise timing, 54. Up 2, 56 ... Slow Time, 58... Diagnostic window generation circuit, 61... Active clamp circuit, 62... Current regeneration diode destruction / opening time, 63 ... boost voltage value, 64 ... clamp voltage value, 65 ... filter time, 66. DESCRIPTION OF SYMBOLS 1,70 ... Current regeneration diode destruction detection threshold value 2, 74 ... Count-up 1, 80 ... Current detection circuit, 81 ... Current detection resistor, 81A ... High side current, 81B ... Regenerative current, 84 ... Peak current, 85 ... Reverse current , 100 ... Peak current threshold, 103 ... Electromagnetic load upstream voltage, 104 ... Skyline threshold, 105 ... Constant value of low-side driver drain voltage, 106 ... Constant value of high-side driver drain voltage, 107 ... High-side driver source voltage Constant value 108... Chopping drive signal generation circuit 109 109 chopping drive signal 11 DESCRIPTION OF SYMBOLS 1 ... Drive signal changeover switch for electric current adjustment, 112 ... Diagnosis window signal, 113 ... Potential fluctuation by noise, 114 ... High side driver drain voltage, 115 ... High side driver source voltage, 116 ... Skylight detection timing, 300 ... Jumping voltage , 301 ... Delay time variable circuit, 302 ... Drop voltage.

Claims (2)

Electromagnetic load,
A power source of the electromagnetic load;
A switch element for a driver arranged at least between the power source and the electromagnetic load and between the electromagnetic load and a power supply ground to drive the electromagnetic load;
A diagnostic means for diagnosing a fault in the circuit configuration by detecting a voltage abnormality between the electromagnetic load and the switch element;
A first current amount adjusting means as an attenuating means for attenuating back electromotive energy generated when the electromagnetic load is interrupted;
Setting means for setting a time zone for detecting the voltage abnormality;
The switch element is an FET;
A second current amount adjusting means for converging the drain voltage of the switch element to a predetermined level;
The first current amount adjusting unit includes a first current source, and when the diagnostic unit detects a power supply fault of the electromagnetic load, the first current source is turned on and a drain voltage of the switch element is detected. To attenuate
The second current amount adjusting means has a second current source, and when the second current source is turned on, the drain voltage of the switch element attenuated by the first current amount adjusting means is The first current amount adjusting means is lowered more slowly than attenuated,
The setting means sets the detection timing of the voltage abnormality in accordance with the energization start timing of the electromagnetic load in which the electromagnetic load cutoff and the energization of the electromagnetic load are repeated.
An electromagnetic load control device. Electromagnetic load,
A power source of the electromagnetic load;
A switch element for a driver arranged at least between the power source and the electromagnetic load and between the electromagnetic load and a power supply ground to drive the electromagnetic load;
A diagnostic means for diagnosing a fault in the circuit configuration by detecting a voltage abnormality between the electromagnetic load and the switch element;
A first current amount adjusting means as an attenuating means for attenuating back electromotive energy generated when the electromagnetic load is interrupted;
Setting means for setting a time zone for detecting the voltage abnormality;
The switch element is an FET;
A second current amount adjusting means for converging the drain voltage of the switch element to a predetermined level;
The first current amount adjusting unit includes a first current source, and when the diagnostic unit detects a power supply fault of the electromagnetic load, the first current source is turned on and a drain voltage of the switch element is detected. To attenuate
The second current amount adjusting means has a second current source, and when the second current source is turned on, the drain voltage of the switch element attenuated by the first current amount adjusting means is The first current amount adjusting means is lowered more slowly than attenuated,
The setting means sets the detection timing of the voltage abnormality to a rising timing or falling timing of a control signal for driving the switch element;
An electromagnetic load control device.

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