JP2006329129A - Engine control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine control system of a simple constitution for enabling a vehicle to run without difficulty that has maintained engine characteristics for shunting even under abnormal conditions of a microcomputer. <P>SOLUTION: A second microcomputer 20 effects a force-resetting of a first microcomputer 10 where irregularity has been detected, and disables the commands of the microcomputer 10 for injection and ignition. The microcomputer 20 establishes commands in time sequence for injection and ignition of fuel injection valves IJ1-IJ4 and an ignition device 80 on the basis of rotational speed and the like of the vehicle-mounted engine, and sends them in serial transmission to an output driver 30. The output driver 30 is provided with a shift register which processes shift of injection and ignition commands whenever the commands are received. The fuel injection valves IJ1-IJ4 and the ignition device 80 are driven on the basis of OR conditions of the infection command and the ignition command which are temporarily stored in respective stages of the shift register, and an injection command and an ignition command which are electrically parallel input from the first microcomputer 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine control device that controls fuel injection, ignition timing, and the like of an in-vehicle engine.

As is well known, this type of engine control device usually monitors a microcomputer that performs fuel injection control and ignition control of the engine based on the outputs of various sensors that monitor the operating state of the engine and vehicle. And a monitoring device for detecting the presence or absence of abnormality of the microcomputer. Also, such an engine control device has a function of enabling so-called vehicle retreat travel by performing fuel injection control and ignition control by means other than the microcomputer when an abnormality of the microcomputer is detected. It is often done. That is, in such an engine control device, for example, a backup IC for retreat travel is provided, and when the microcomputer is abnormal, fuel injection based on the engine speed signal input from the speed sensor through the back-up backup IC is performed. Control and ignition control are executed so that the vehicle is evacuated.
JP-A-5-163998

  By the way, according to the engine control apparatus provided with the backup IC, the retreat traveling is surely realized, but the fuel injection control executed through the backup IC is performed in a fixed amount based only on the engine speed signal. Cylinder simultaneous injection. For this reason, it is possible to perform only extremely simple control as compared with the fuel injection control performed through the microcomputer in a normal state. For example, when retreating on a rough road such as off-road, it is sufficient for traveling of the vehicle. Inconveniences such as inability to obtain a proper torque may occur.

  Conventionally, as an engine control device equipped with such a function that enables retreat traveling, for example, the one described in Patent Document 1 is known, but this is simply provided with two microcomputers, In the event of an abnormality, the processing (control) is merely substituted on the other side, and an increase in the scale of the engine control device is inevitable.

  The present invention has been made in view of the above circumstances, and its purpose is to maintain engine characteristics even when the microcomputer is abnormal, while having a simple configuration without causing an increase in circuit scale or cost. An object of the present invention is to provide an engine control device that enables smoother retreat travel of a vehicle.

  In order to achieve such an object, the invention according to claim 1 generates injection commands and ignition commands for a plurality of fuel injection valves and a plurality of ignition devices of the engine based on the rotational speed information and the intake air amount information of the in-vehicle engine. A microcomputer that performs the output, an output driver that drives the plurality of fuel injection valves and the plurality of ignition devices based on the generated injection command and ignition command, and a monitoring device that monitors whether there is an abnormality in the operation of the microcomputer As the engine control device, the monitoring device, when the microcomputer is abnormal, forcibly resets the microcomputer to invalidate the injection command and the ignition command issued from the microcomputer, and the rotational speed of the in-vehicle engine The plurality of fuel injection valves and the plurality of ignition devices based on the information The injection command and the ignition command are generated in time series and transmitted to the output driver by serial communication. In the output driver, the injection command and ignition command are received from the monitoring device by serial communication. As a configuration comprising a shift register that shift-registers this every time, an injection command and an ignition command temporarily held in each stage of the shift register, and an injection command and an ignition command that are electrically input in parallel from the microcomputer The plurality of fuel injection valves and the plurality of ignition devices are driven based on the logical OR condition.

  As described above, in the engine control device having a so-called retreat traveling function, when the microcomputer that outputs the injection command and the ignition command is abnormal, the microcomputer is stopped and the fuel injection control and the ignition control are performed by other means. However, in order to avoid an increase in circuit scale and cost, simple fuel injection control of simultaneous injection of all cylinders at a fixed amount is performed. In this regard, when the microcomputer is abnormal, the monitoring device generates an injection command and an ignition command for each fuel injection valve and each ignition device in time series, and outputs this to the output driver by serial communication. Accordingly, the fuel injection valve as well as each ignition device can be controlled individually by the injection command and the ignition command generated in time series. For this reason, the fuel injection control at the time of evacuation traveling can be realized in a manner close to the normal time of the microcomputer while the configuration is simple without causing an increase in circuit scale or cost. It becomes possible.

  Further, in the engine control device according to claim 1, in the invention according to claim 2, the monitoring device operates the microcomputer based on a transition of a watchdog signal output from the microcomputer. After detecting the abnormality of the microcomputer, the invalidation control for the injection command and the ignition command issued from the microcomputer is continued until the ignition switch is turned off. .

  According to such a configuration, when an abnormality of the microcomputer is detected, the switching from the microcomputer to the monitoring device can be smoothly performed as a main subject of drive control of the plurality of fuel injection valves and the plurality of ignition devices. As a result, control hunting does not occur between the microcomputer and the monitoring device.

  Further, in the engine control device according to claim 1 or 2, in the invention according to claim 3, the monitoring device captures accelerator opening information of the in-vehicle engine together, and the acquired accelerator opening information In consideration of the above, the injection command is generated.

  According to such a configuration, the fuel injection amount is controlled in accordance with the accelerator opening that reflects the driver's will while being in the retreat travel, so that the fuel injection control during the retreat travel is further improved. As well as being able to perform smoothly, it is also easy to obtain the torque required for the vehicle traveling each time.

  Further, in the engine control device according to any one of claims 1 to 3, in the invention according to claim 4, the monitoring device captures intake air amount information of the in-vehicle engine together, and the intake air amount acquired The injection command is generated in consideration of information.

  According to such a configuration, the fuel injection amount is controlled according to the actual intake air amount of the in-vehicle engine while in the retreat travel, so that the fuel injection control during the retreat travel is It will be realized more smoothly. Further, when such a configuration is combined with the configuration described in claim 3 above, the vehicle evacuation travel is realized in a manner closer to the normal state of the microcomputer, including the torque required each time. It becomes like.

  Further, in the engine control device according to any one of claims 1 to 4, in the invention according to claim 5, the output driver is driven for each of the plurality of fuel injection valves and the plurality of ignition devices. Means for extracting the accompanying current, and means for transferring the state of the extracted current as a serial signal to the monitoring device in time series, wherein the monitoring device transmits the serial signal to be transferred Based on the above, for the fuel injection valve or ignition device in which the state of the extracted current is abnormal, the control for invalidating the corresponding injection command or ignition command is also executed.

  According to such a configuration, the microcomputer is limited to the fuel injection control and the ignition control based on the serial signal indicating the state of the current extracted with the driving of each fuel injection valve and each ignition device in time series. Even when the fuel injection control and the ignition control are performed by the monitoring device, the abnormality of the plurality of fuel injection valves and the plurality of ignition devices can be detected separately. Since the corresponding injection command or ignition command is invalidated for the fuel injection valve or ignition device in which the abnormality is detected, the drive of the abnormal fuel injection valve or ignition device is prohibited, and a suitable fail-safe is achieved. Become figured.

  Further, in the engine control device according to claim 5, in the invention according to claim 6, the control for invalidating the injection command or the ignition command by the monitoring device is performed when the state of the extracted current is abnormal. In response to the drive timing of the fuel injection valve or the ignition device, the monitoring device outputs the shutdown command to the output driver, and the output driver temporarily applies to each stage of the shift register. The logical product condition of the signal obtained by the logical sum condition of the held injection command and ignition command and the injection command and ignition command electrically input in parallel from the microcomputer and the logical inversion signal of the shutdown command Based on this, the corresponding fuel injection valves and ignition devices were driven.

  According to such a configuration, the shutdown command is input as one of the logical product conditions which is the final stage in outputting the drive signal as the output driver. Therefore, it is easy and accurate through the shutdown command. In addition, invalid control of the fuel injection valve or the ignition device is performed.

  Further, in the engine control device according to any one of claims 1 to 6, the invention according to claim 7 further includes an injection monitoring means for monitoring each energization state of the plurality of fuel injection valves. In the monitoring device, the state of the fuel injection valve is also monitored based on the monitored energization state.

  According to such a configuration, even if an abnormality such as a constant energization occurs in any of the plurality of fuel injection valves based on a signal from the injection monitoring means obtained as a response to the injection command, Can be accurately detected in terms of hardware.

  Further, in the engine control device according to any one of claims 1 to 7, the monitoring device may be configured as a dedicated IC, for example, according to the invention according to claim 8, or may be claimed. According to the invention described in item 9, it can be configured by an auxiliary microcomputer. In particular, even when the monitoring device is constituted by an auxiliary microcomputer, when the microcomputer is abnormal, the injection commands and the ignition commands for the plurality of fuel injection valves and the plurality of ignition devices are time-series based on the rotational speed information of the in-vehicle engine. Therefore, it is possible to suitably suppress an increase in circuit scale by using a configuration in which it is generated and transmitted to the output driver through serial communication.

Hereinafter, an embodiment of an engine control device according to the present invention will be described with reference to FIGS.
FIG. 1 shows the electrical configuration of the engine control apparatus of the present embodiment. As shown in FIG. 1, the engine control apparatus according to the present embodiment is roughly composed of a first microcomputer 10, a second microcomputer (monitoring device) 20, an output driver 30, and an injection monitor (injection monitoring means). 40. Further, a rotational speed sensor 50 is connected to the terminal P1 of the engine control device, an intake air amount sensor 60 is connected to the terminal P2, and an accelerator sensor 70 is connected to the terminal P3. The signals of the rotational speed sensor 50 and the intake air amount sensor 60 are input to the first microcomputer 10 and the second microcomputer, and the signal of the accelerator sensor 70 is input to the second microcomputer 20. Has been. Further, the fuel injection valves IJ1 to IJ4 provided corresponding to the cylinders # 1 to # 4 of the in-vehicle engine are provided at terminals S1 to S4 of the engine control device, and the in-vehicle engines are provided at terminals S5 to S8. Ignition devices 80 each including an ignition plug, an igniter, and the like that perform fuel ignition corresponding to cylinders # 1 to # 4 are connected to each other. The fuel injectors IJ1 to IJ4 and the ignition device 80 are connected to the output driver 30 via the terminals S1 to S8.

Next, each element constituting the engine control device will be described.
The first microcomputer 10 generates injection commands and ignition commands corresponding to the fuel injection valves IJ1 to IJ4 and the ignition device 80 based on signals input from the sensors 50 and 60, and the generated injections. A command and an ignition command are output to the output driver 30. The first microcomputer 10 is connected to the output driver 30 through eight signal lines corresponding to the fuel injection valves IJ1 to IJ4 and the ignition device 80. The fuel injection valves IJ1 to IJ4 and the ignition device 80 are connected to the output driver 30. The above-mentioned injection command and ignition command corresponding to are output electrically in parallel via these eight signal lines.

  The second microcomputer 20 performs electronic throttle control based on accelerator opening information input from the accelerator sensor 70 or the like as an auxiliary microcomputer of the first microcomputer 10. The second microcomputer 20 detects an abnormality of the first microcomputer 10 based on the transition of the watchdog signal input from the first microcomputer 10. When the abnormality of the first microcomputer 10 is detected, the second microcomputer 20 forcibly resets the first microcomputer 10 and outputs the jet outputted from the first microcomputer 10. Command and ignition command are disabled. Thereby, the fuel injection control and the ignition control by the first microcomputer 10 are stopped. This invalidation control is continued until the ignition switch that is the start switch of the vehicle-mounted engine is turned off.

  In addition, the second microcomputer 20 replaces the first microcomputer 10 in which the abnormality is detected and the injection command and the ignition command are invalidally controlled as described above. Ignition control is performed. The second microcomputer 20 shows the injection commands and the ignition commands corresponding to the fuel injection valves IJ1 to IJ4 and the ignition device 80 in time series based on the information obtained from the sensors 50, 60 and 70. A bit serial drive command is generated and output to the output driver 30 by serial communication. Note that the transmission of the serial drive command from the second microcomputer 20 to the output driver 30 is performed at a cycle of, for example, 1 ms (milliseconds). Further, as the communication speed at this time, it is necessary to consider the reception time of the serial drive command. For the transmission period of 1 ms, for example, a communication speed of 1 Mbps (Mega bit per second) is adopted. Is done. When the first microcomputer 10 is normal, the serial drive command input from the second microcomputer 20 to the output driver 30 is “0” for all of the injection command and the ignition command. Maintained as.

  In addition to the serial drive command from the second microcomputer 20 to the output driver 30, a clock required when the output driver 30 receives the serial drive command and the fuel injection valves IJ1 to IJ1. When there is an abnormality in the IJ4 and the ignition device 80, a shutdown command for invalid control of the abnormality and making it non-driven is output. On the other hand, a fail status signal indicating the driving state of the fuel injection valves IJ1 to IJ4 and the ignition device 80 is output from the output driver 30 to the second microcomputer 20 by serial communication. The shutdown command and fail status signal will be described in detail later.

  The injection monitor 40 monitors each energization state of the fuel injection valves IJ1 to IJ4, and includes diodes 40a to 40d, voltage dividing resistors 41a and 41b, and a comparator 42. . The voltage divided by the voltage dividing resistors 41a and 41b is input to the non-inverting input terminal of the comparator 42, and the voltage in the current path of the fuel injectors IJ1 to IJ4 is input to the inverting input terminal of the comparator 42. Is input via the diodes 40a to 40d. As a result, the comparator 42 outputs a signal corresponding to energization or non-energization of each of the fuel injection valves IJ1 to IJ4, and the second microcomputer 20 to which the output of the comparator 42 is input outputs the fuel injection. Abnormal energization abnormalities of the valves IJ1 to IJ4 are detected.

  FIG. 2 shows the electrical configuration of the output driver 30. As shown in FIG. 2, the output driver 30 inputs the injection command output from the first microcomputer 10 through terminals Q1 to Q4 corresponding to the cylinders # 1 to # 4, and The ignition command output from one microcomputer 10 is input via terminals Q5 to Q8 corresponding to cylinders # 1 to # 4. In FIG. 2, the injection command and ignition command processing circuits input via these terminals Q1 to Q8 all have the same configuration, so that only the injection command processing circuit input via the terminal Q4 is provided. The illustration is omitted. The injection command input from the first microcomputer 10 via the terminal Q4 is input to the Schmitt trigger circuit 31 and is subjected to waveform shaping and then input to the OR circuit 33. The constant current source 32a provided in the input path to the Schmitt trigger circuit 31 is for dropping the signal level to a low level so as to determine the phase at the time of initial.

  The output driver 30 inputs the serial drive command output from the second microcomputer 20 via a terminal Q9. The serial drive command input via this terminal Q9 is received by the shift register 34 composed of flip-flops 34a to 34h. In the shift register 34, the received injection command and ignition command are temporarily held in each stage of the flip-flops 34a to 34h based on the clock input via the terminal Q10.

  Here, the transfer of the serial drive command between the second microcomputer 20 and the output driver 30 will be described with reference to FIG. As shown in FIG. 3A, in the second microcomputer 20, the least significant bit LSB (Least Significant Bit) side 4 bits are set to the ignition command of the cylinders # 1 to # 4, and the most significant bit MSB (Most Significant Bit). ) An 8-bit serial drive command is generated in which the 4-bit side is an injection command for cylinders # 1 to # 4. The serial drive command generated in this way is transmitted from the second microcomputer 20 to the output driver 30 by MSB first sequentially transmitted from the most significant bit MSB side. On the other hand, in the output driver 30, the serial drive command is shift-registered in the flip-flops 34a to 34h in accordance with the clock input from the second microcomputer 20. When the data shift of the serial drive command is completed, the injection command and the ignition command are held in the flip-flops 34a to 34h as shown in FIG. 3A and 3B illustrate a serial drive command when the injection command for cylinder # 1 is on and a serial drive command when the ignition command for cylinder # 1 is on.

  In the output driver 30, after the data shift to the respective stages of the flip-flops 34a to 34h is completed, the flip-flops 34a to 34h are supplied to the flip-flops 34a to 34h in accordance with the transmission period (for example, 1 ms) of the serial drive command. The held injection command and ignition command are read simultaneously as an 8-bit signal. In FIG. 2, the injection command and ignition command processing circuits read from the flip-flops 34a to 34h have the same configuration, and therefore only the injection command processing circuit read from the flip-flop 34h corresponding to cylinder # 4. The other circuits are not shown. The constant current source 32b provided in the input path for the serial drive command is for lowering the signal level to a low level so as to determine the phase at the time of initialization, similar to the constant current source 32a.

  The injection command corresponding to the cylinder # 4 read from the flip-flop 34h is input to the OR circuit 33 together with the injection command from the first microcomputer 10 corresponding to the cylinder # 4. As a result, the OR circuit 33 determines the logical sum condition between the injection command for the cylinder # 4 from the first microcomputer 10 and the injection command for the cylinder # 4 from the second microcomputer 20. As described above, since the injection command and the ignition command of the second microcomputer 20 are all maintained at “0” unless an abnormality of the first microcomputer 10 is detected, the first microcomputer 10 is maintained. When the computer 10 is normal, the injection command of the first microcomputer 10 is reflected as the output of the OR circuit 33 as it is. On the other hand, when the first microcomputer 10 is abnormal, the injection command and ignition command of the first microcomputer 10 are invalidally controlled by the second microcomputer 20 as described above. Since the signal level is set to the low level, the injection command and the ignition command of the second microcomputer 20 are reflected as they are as the output of the OR circuit 33. The output of the OR circuit 33 is input to the AND circuit 35.

  The output driver 30 inputs the shutdown command output from the second microcomputer 20 via a terminal Q11. The shutdown command input via this terminal Q11 shuts down all of the fuel injection valves IJ1 to IJ4 and the ignition device 80, and is input to the AND circuit 35 together with the output of the OR circuit 33 so that the logical product condition is satisfied. To be judged. The second microcomputer 20 maintains the signal level of the shutdown command at a high level unless the fuel injectors IJ1 to IJ4 and the ignition device 80 are abnormal. The output of the AND circuit 35 is reflected as it is. On the other hand, when the fuel injection valves IJ1 to IJ4 and the ignition device 80 are abnormal, the second microcomputer 20 determines the signal level of the shutdown command in accordance with the drive timing of the fuel injection valve or ignition device where the abnormality is detected. In order to drop the signal to low level, the output of the AND circuit 35 is invalidated by this shutdown command.

  The output driver 30 turns on or off the switching element 36 that turns on or off the energization of the fuel injection valve IJ4 based on the output signal of the AND circuit 35. When a high level signal is output from the AND circuit 35 and the switching element 36 is turned on, current flows from the battery B to the fuel injection valve IJ4, and fuel flows from the fuel injection valve IJ4 to the cylinder # 4. Be injected. The other fuel injection valves IJ1 to IJ3 and the ignition device 80 are also driven in the same manner as the fuel injection valve IJ4.

  The output driver 30 includes a current detection resistor 37, a comparator 38, and a serial out circuit 39. The current detection resistor 37 is provided on the downstream side of the switching element 36 in the current path of the fuel injection valve IJ4. The comparator 38 compares the voltage between the switching element 36 and the current detection resistor 37 with a predetermined voltage V1 and outputs the result as a cylinder # 4 injection state signal. The fuel injection valve IJ4 When the fuel injection valve IJ4 is in a non-energized state, a low level signal is output when in the energized state, and a high level signal is output. Similarly, the energization states of the fuel injection valves IJ1 to IJ3 and the ignition device 80 are similarly input to the serial out circuit 39 as cylinder # 1 to # 3 injection state signals and cylinder # 1 to # 4 ignition state signals. The serial-out circuit 39 chronologically determines the energization states of the fuel injection valves IJ1 to IJ4 and the ignition device 80 based on the cylinder # 1 to # 4 injection state signals and the cylinder # 1 to # 4 ignition state signal outputs. An 8-bit fail status signal is generated and transferred to the second microcomputer 20 via the terminal Q12 by serial communication. This fail status signal is shown in FIG. As shown in FIG. 4, this fail status signal is such that the bit corresponding to the driven fuel injection valve or ignition device is set to “1”. In FIG. 4, as an example, the fuel by the fuel injection valve IJ4 This is when injection is performed.

  On the other hand, the second microcomputer 20 monitors the states of the fuel injection valves IJ1 to IJ4 and the ignition device 80 based on the fail status signal input from the output driver 30. Here, when a fail status signal whose bit corresponding to the injection of the cylinder # 4 is not input even though the injection command for turning on the fuel injection valve IJ4 is transmitted, the second microcomputer 20 determines that the fuel injection valve IJ4 is abnormal. Then, after detecting the abnormality of the fuel injection valve IJ4, the second microcomputer 20 changes the signal level of the shutdown command from “1” to “0” in accordance with the drive timing of the fuel injection valve IJ4. To disable the drive of the fuel injection valve IJ4. It should be noted that these abnormalities are also detected for the other fuel injection valves IJ1 to IJ3 or the ignition device 80 based on the fail status signal, and invalidation control based on the shutdown command is executed.

  Next, in the engine control apparatus having such a configuration, when the fuel injection control and the ignition control are performed by the first microcomputer 10, the second microcomputer is used as a retreat travel when the first microcomputer 10 is abnormal. Each case where the fuel injection control and the ignition control are performed by the computer 20 will be described. In the engine control apparatus of the present embodiment, fuel injection control and ignition control are performed in the cycles of cylinders # 1, # 3, # 4, and # 2.

(Fuel injection control and ignition control by the first microcomputer 10)
The first microcomputer 10 generates an interrupt at every falling timing of the crank signal input from the rotation speed sensor 50 to calculate the rotation speed, check the current position of the crank angle, and the like. In the first microcomputer 10, the position at which the crank signal is to be injected or ignited is determined for each cylinder # 1 to # 4 in advance, and the load state (rotation speed, intake air amount, etc.) of the in-vehicle engine. The fuel injection time and ignition time corresponding to the above, and the fuel injection end time and ignition end time are always calculated by the base routine. Hereinafter, the fuel injection control and the ignition control by the first microcomputer 10 will be described with reference to time charts of various signals shown in FIGS.
(A) First, when performing the injection of the cylinder # 1, the first microcomputer 10 performs the injection end timing of the cylinder # 2 under the crank signal (FIG. 5A) input from the rotational speed sensor 50. To a timing t11 after elapse of a predetermined time, a fuel injection time and a fuel injection end timing t13 are calculated based on the load state of the in-vehicle engine. Then, the first microcomputer 10 determines the fuel injection start timing t12 by subtracting the fuel injection time from the calculated fuel injection end timing t13.
(B) Subsequently, at the fuel injection start timing t12, the first microcomputer 10 sets the output level of the injection command of the cylinder # 1 to a high level until the calculated fuel injection time elapses. As a result, the fuel injection valve IJ1 is driven through the output driver 30 in an energized state as shown in FIG. The first microcomputer 10 lowers the output level of the injection command of the cylinder # 1 to a low level after the fuel injection time has elapsed.
(C) The first microcomputer 10 executes the ignition control of the cylinder # 1 after the fuel injection of the cylinder # 1 is completed. This ignition control is performed in the same manner as the fuel injection control shown in (a) and (b) above. That is, the ignition time and the ignition end timing are calculated under the crank signal (FIG. 5A) input from the rotational speed sensor 50, and the ignition start timing t14 is determined by subtracting the ignition time from the ignition end timing. To do. Then, at the ignition start timing t14, the first microcomputer 10 sets the output level of the ignition command for the cylinder # 1 to a high level until the calculated ignition time has elapsed. The first microcomputer 10 lowers the output level of the ignition command of the cylinder # 1 to a low level after the ignition time has elapsed. As a result, the ignition command shown in FIG. 5G is output from the first microcomputer 10 to the output driver 30, and the ignition device 80 performs fuel ignition in the cylinder # 1.

In the first microcomputer 10, fuel injection and ignition are executed for the cylinders # 3, # 4, and # 2 in the same manner as in the above (a) to (c).
That is, in the fuel injection control of these cylinders # 3, # 4, and # 2, the cylinder # 3 is based on the load state of the vehicle-mounted engine from the end of fuel injection of the previous cylinder to the timing t31, t41, and t21. , # 4, # 2 and fuel injection end timings t33, t43, t23 are calculated. Then, fuel injection start timings t32, t42, and t22 are determined by subtracting the calculated fuel injection time from the time until the fuel injection end timings t33, t43, and t23. When the fuel injection start timings t32, t42, and t22 are reached, the output levels of the injection commands of the cylinders # 3, # 4, and # 2 are kept high until the calculated fuel injection time elapses. Thereby, the fuel injection valves IJ3, IJ4, IJ2 are driven through the output driver 30 in the energized state as shown in FIGS. Then, after the fuel injection time has elapsed, the output level of the injection command of the cylinders # 3, # 4, and # 2 is lowered to a low level.

  On the other hand, in the ignition control of the cylinders # 3, # 4, and # 2, similarly, the ignition time and the ignition end timing are calculated, and the ignition start timing t34, t44, t24 is determined. When the ignition start timings t34, t44, and t24 are reached, the output levels of the ignition commands of the cylinders # 3, # 4, and # 2 are kept high until the calculated ignition time has elapsed. After the ignition time elapses, the output level of the ignition command for the cylinders # 3, # 4, and # 2 is lowered to a low level. As a result, ignition commands shown in FIGS. 5H to 5J are output from the first microcomputer 10 to the output driver 30, and the ignition device 80 causes the cylinders # 3, # 4, # to be output. Fuel ignition in 2 is performed.

  Note that a signal shown in FIG. 5F is output from the comparator 42 of the injection monitor 40 to the second microcomputer 20 in accordance with the driving of the fuel injection valves IJ1 to IJ4. The second microcomputer 20 monitors abnormalities such as constant energization of the fuel injection valves IJ1 to IJ4 based on this signal.

(Fuel injection control and ignition control by the second microcomputer 20)
The second microcomputer 20 generates an interrupt at every falling timing of the crank signal input from the rotation speed sensor 50 to calculate the rotation speed, check the current position of the crank angle, and the like. In this second microcomputer 20, the position at which the crank signal is to be injected or ignited is determined in advance for each cylinder # 1 to # 4, and the fuel injection time and ignition according to the load state of the in-vehicle engine are determined. The time, the fuel injection end time, and the ignition end time are always calculated by the base routine. Hereinafter, the fuel injection control and the ignition control by the second microcomputer 20 will be described with reference to time charts of various signals shown in FIGS.
(D) First, the second microcomputer 20 performs the injection end timing of the cylinder # 2 under the crank signal (FIG. 6A) input from the rotational speed sensor 50 when performing the injection of the cylinder # 1. To a timing t101 after a predetermined time elapses, a fuel injection time and a fuel injection end timing t103 are calculated based on the load state of the vehicle-mounted engine. Then, the second microcomputer 20 determines the fuel injection start timing t102 by subtracting the fuel injection time from the calculated fuel injection end timing t103.
(E) Subsequently, at the fuel injection start timing t102, the second microcomputer 20 performs the injection in which the bit corresponding to the cylinder # 1 is set to “1” in accordance with the calculated fuel injection time. A serial drive command (FIG. 3A) including the command (FIG. 6B) is transmitted to the output driver 30 by serial communication. If the transmission period of the serial drive command from the second microcomputer 20 to the output driver 30 is 1 ms, for example, and the calculated fuel injection time is 5 ms, it is shown in FIG. Thus, the serial drive command is transmitted five times. As a result, the fuel injection valve IJ1 is driven through the output driver 30 in an energized state as shown in FIG.
(F) The second microcomputer 20 executes the ignition control of the cylinder # 1 after the fuel injection of the cylinder # 1 is completed. This ignition control is performed in the same manner as the fuel injection control shown in the above (d) and (e). That is, the ignition time and the ignition end timing are calculated under the crank signal (FIG. 6A) input from the rotational speed sensor 50, and the ignition start timing t104 is determined by subtracting the ignition time from the ignition end timing. To do. Then, at the ignition start timing t104, the second microcomputer 20 includes a serial drive command (FIG. 6H) including an ignition command (FIG. 6H) in which the bit corresponding to the cylinder # 1 is set to “1”. 3 (a)) is transmitted to the output driver 30 by serial communication. If the transmission period of the serial drive command is 1 ms, for example, and the calculated ignition time is 3 ms, the serial drive command is transmitted three times as shown in FIG. Become. As a result, the ignition signal of the cylinder # 1 shown in FIG. 6 (i) is output from the flip-flop 34a of the output driver 30, and the ignition device 80 performs fuel ignition in the cylinder # 1.

In the second microcomputer 20, fuel injection and ignition are executed for the cylinders # 3, # 4, and # 2 in the same manner as in the above (d) to (f).
That is, in the fuel injection control of these cylinders # 3, # 4, and # 2, the cylinder # 3 is based on the load state of the vehicle-mounted engine from the end of fuel injection of the previous cylinder to the timing t301, t401, and t201. , # 4 and # 2, and fuel injection end timings t303, t403, and t203 are calculated. Then, fuel injection start timings t302, t402, and t202 are determined by subtracting the calculated fuel injection time from the fuel injection end timings t303, t403, and t203. At the fuel injection start timings t302, t402, and t202, a serial drive command including an injection command (FIG. 6B) in which the bits corresponding to the cylinders # 3, # 4, and # 2 are set to “1”. (FIG. 3A) is transmitted to the output driver 30 by serial communication by an amount corresponding to the calculated fuel injection time (for example, 5 ms). As a result, the fuel injection valves IJ3, IJ4, IJ2 are driven through the output driver 30 in an energized state as shown in FIGS.

  On the other hand, in the ignition control of the cylinders # 3, # 4, and # 2, similarly, the ignition time and the ignition end timing are calculated, and the ignition start timing t304, t404, t204 is determined. At the ignition start timings t304, t404, and t204, a serial drive command (including an ignition command (FIG. 6 (h)) in which the bits corresponding to the cylinders # 3, # 4, and # 2 are set to “1” ( FIG. 3A is transmitted to the output driver 30 by serial communication. As a result, the ignition signals corresponding to the cylinders # 3, # 4, and # 2 shown in FIGS. 6 (j) to (l) are output from the flip-flops 34b to 34d of the output driver 30, and the ignition device 80 outputs the ignition signals. Fuel ignition is performed in cylinders # 3, # 4, and # 2.

  The signal shown in FIG. 6G is output from the comparator 42 of the injection monitor 40 to the second microcomputer 20 in accordance with the driving of the fuel injection valves IJ1 to IJ4. The second microcomputer 20 monitors abnormalities such as constant energization of the fuel injection valves IJ1 to IJ4 based on this signal.

According to the embodiment described above, the effects listed below can be obtained.
(1) When the first microcomputer 10 is abnormal, the second microcomputer 20 generates injection commands and ignition commands for the fuel injection valves IJ1 to IJ4 and the ignition device 80 in time series. The data is output to the output driver 30 by serial communication. Therefore, the fuel injection valves IJ1 to IJ4 as well as the ignition device 80 can be controlled separately by the injection command and the ignition command generated in time series. Therefore, the fuel injection control at the time of evacuation travel can be realized in a manner close to the normal time of the first microcomputer 10 while having a simple configuration that does not increase the circuit scale and cost. Evacuation is possible.

  (2) After the abnormality of the first microcomputer 10 is detected, the ignition switch performs invalid control for the injection command and the ignition command issued by the second microcomputer 20 from the first microcomputer 10. It was decided to continue until it was turned off. For this reason, when an abnormality of the first microcomputer 10 is detected, the first microcomputer 10 to the second microcomputer 20 serve as a main body of drive control of the fuel injection valves IJ1 to IJ4 and the ignition device 80. Switching to is performed smoothly and accurately. In addition, no control hunting occurs between the first microcomputer 10 and the second microcomputer 20.

  (3) The second microcomputer 20 generates the injection command in consideration of the intake air amount information and the accelerator opening information input from the intake air amount sensor 60 and the accelerator sensor 70 even during the retreat travel. . For this reason, the fuel injection amount is controlled in accordance with the actual intake air amount and the accelerator opening degree of the in-vehicle engine while in the evacuation travel, so that the first torque including the required torque is included in each case. The evacuation traveling of the vehicle is realized in a manner closer to the normal state of the microcomputer 10.

  (4) The second microcomputer 20 outputs the shutdown command in response to the drive timing of the fuel injection valve or the ignition device in which an abnormality is detected based on the fail status signal. As a result, for the fuel injection valve or ignition device in which an abnormality is detected, the corresponding injection command or ignition command is invalidated, so that the drive of the abnormal fuel injection valve or ignition device is prohibited, and a suitable failsafe Comes to be planned.

  (5) As the output driver 30, an injection command and an ignition command temporarily held in each stage of the shift register 34, and an injection command and an ignition command that are electrically input from the first microcomputer 10 in parallel Based on the logical product condition (AND circuit 35) of the signal obtained by the logical sum condition (OR circuit 33) and the logically inverted signal of the shutdown command, the one that drives each corresponding fuel injection valve and ignition device is adopted. did. As a result, the shutdown command is input as one of the logical product conditions, which is the final stage in outputting the drive signal as the output driver 30, so that the abnormalities can be detected easily and accurately through the shutdown command. Ineffective control of a certain fuel injection valve or ignition device is performed.

  (6) The second microcomputer 20 monitors the state of the fuel injectors IJ1 to IJ4 through the injection monitor 40 that monitors the energized state of the fuel injectors IJ1 to IJ4. For this reason, even if an abnormality such as normal energization occurs in any of the plurality of fuel injection valves IJ1 to IJ4 based on a signal from the injection monitor 40 obtained as a response to the injection command, the abnormality is hardened. It becomes possible to detect accurately from the aspect of wear.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, the second microcomputer 20 monitors the first microcomputer 10 and, in the event of an abnormality, performs fuel injection control and ignition control in place of the first microcomputer 10 to save. It was decided to realize traveling. Instead of this, the evacuation traveling may be realized by using a monitoring-dedicated IC in which a function equivalent to that of the second microcomputer 20 is converted into a custom LSI. In this case, for example, as shown in FIG. 7, the microcomputer 100 responsible for overall engine control and the monitoring IC 200 having the retreat travel control unit 200a are provided. The monitoring IC 200 monitors the abnormality of the microcomputer 100. When the abnormality is detected, the retreat travel control unit 200a performs fuel injection control and ignition control in the same manner as in the above embodiment. As a result, as in the above embodiment, smooth retreat travel is realized. Further, in the case where the monitoring-dedicated IC is used as described above, when the fuel injection amount is changed according to the accelerator opening, it is possible to adopt, for example, the monitoring IC 200 equipped with the circuit shown in FIG. That is, as shown in FIG. 8, the signal voltage of the accelerator sensor 70 is compared with the predetermined voltage V2 divided by the voltage dividing resistors 202 and 203 by the comparator 201, and the signal voltage of the accelerator sensor 70 is obtained. When it is larger than the divided voltage, the fuel injection amount is increased. Note that the same configuration can be realized when the fuel injection amount is changed in accordance with the intake air amount. In addition, when using a monitoring-dedicated IC in this way, it is possible to change the fuel injection amount in accordance with a crank signal input from the rotational speed sensor 50. For example, the fuel injection valves IJ1 to IJ1- The injection amount is adjusted by shortening the valve opening time of IJ4.

  In the above-described embodiment, the configuration including the injection monitor 40 is shown to detect abnormalities such as the constant energization of the fuel injection valves IJ1 to IJ4 from the hardware aspect, but the configuration is omitted. It may be. Even in this case, the second microcomputer 20 can detect the abnormality of the fuel injection valves IJ1 to IJ4 based on the fail status signal input from the output driver 30. The injection monitor 40 is used not only for detecting the abnormality of the fuel injection valves IJ1 to IJ4 but also for monitoring the valve opening time of the fuel injection valves IJ1 to IJ4, and based on the monitored valve opening time. Further, the fuel injection amount at each time may be monitored together.

  On the contrary, a configuration in which the fail status signal is omitted may be employed. Even in this case, it is possible to detect abnormality of the fuel injection valves IJ1 to IJ4 and the ignition device 80 by providing the same one as the injection monitor 40 on the ignition device 80 side.

  In the above embodiment, the shutdown command is output in accordance with the drive timing of the fuel injection valve or ignition device in which the abnormality is detected, thereby performing invalid control of the fuel injection valve or ignition device in which the abnormality is detected. It was. Instead, the invalidation control may be executed simply by the second microcomputer 20 not transmitting the injection command or the ignition command corresponding to the fuel injection valve or the ignition device in which the abnormality is detected.

  In the above embodiment, the abnormality of the first microcomputer 10 is detected through the watchdog signal. However, the abnormality detection of the first microcomputer 10 is detected through means other than the watchdog signal. You may make it do.

  In the above embodiment, the output driver 30 including the shift register 34 and the like configured by the flip-flops 34a to 34h as described above has been described, but an output driver having another configuration may be employed. The point is that a shift register for shifting and registering the injection command and the ignition command inputted from the second microcomputer 20 is provided, and the injection command and the ignition command temporarily held in each stage of the shift register and the first command. As long as the fuel injection valves IJ1 to IJ4 and the ignition device 80 are driven based on a logical sum condition of an injection command and an ignition command that are electrically input from the microcomputer 10 in parallel, other ones are adopted. Can do.

The block diagram which shows the electric constitution about one Embodiment of the engine control apparatus concerning this invention. The block diagram which shows the electrical structure about the output driver which comprises the engine control apparatus of the embodiment. (A) is a serial drive command generated in the second microcomputer, (b) is a diagram showing a serial drive command received in the output driver. The figure which shows the fail status signal output from an output driver. (A)-(j) is a time chart which shows the control aspect about the fuel-injection control and ignition control by a 1st microcomputer. (A)-(l) is a time chart which shows the control aspect about the fuel-injection control and ignition control by a 2nd microcomputer. The block diagram which shows the electric structure about the engine control apparatus of embodiment different from the said embodiment. The circuit diagram which shows a part of the structure about an evacuation travel control part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... 1st microcomputer, 20 ... 2nd microcomputer, 30 ... Output driver, 31 ... Schmitt trigger circuit, 32a, 32b ... Constant current source, 33 ... OR circuit, 34 ... Shift register, 34a-34h ... Flip-flop 35 ... AND circuit, 36 ... switching element, 37 ... current detection resistor, 38 ... comparator, 39 ... serial out circuit, 40 ... injection monitor, 40a to 40d ... diode, 41a, 41b ... voltage dividing resistor, 42 ... comparator , 50 ... Rotational speed sensor, 60 ... Intake amount sensor, 70 ... Accelerator sensor, 80 ... Ignition device, 100 ... Microcomputer, 200 ... Monitoring IC, 200a ... Retreat travel control unit, 201 ... Comparator, 202, 203 ... Partial pressure Resistance, IJ1 to IJ4 ... Fuel injection valves, P1 to P3, S1 to S8 Q1~Q12 ... terminal.

Claims (9)

A microcomputer that generates an injection command and an ignition command for a plurality of fuel injection valves and a plurality of ignition devices of the engine based on the rotational speed information and the intake air amount information of the vehicle-mounted engine, and based on the generated injection command and the ignition command An engine control device comprising: an output driver that drives the plurality of fuel injection valves and a plurality of ignition devices; and a monitoring device that monitors whether the microcomputer operates abnormally;
When the microcomputer is abnormal, the monitoring device forcibly resets the microcomputer to invalidate the injection command and the ignition command issued from the microcomputer, and based on the rotational speed information of the in-vehicle engine, the plurality of fuels An injection command and an ignition command for the injection valve and the plurality of ignition devices are generated in time series and transmitted to the output driver by serial communication. The output driver receives the injection command and the ignition command serially from the monitoring device. A shift register that shift-registers each time it is received by communication, an injection command and an ignition command that are temporarily held in each stage of the shift register, and an injection command that is electrically input in parallel from the microcomputer; The plurality of fuel injection valves based on a logical sum condition with an ignition command The engine control apparatus characterized by driving a micro plurality of ignition devices. The monitoring device monitors whether there is an abnormality in the operation of the microcomputer based on the transition of the watchdog signal output from the microcomputer, and once the abnormality of the microcomputer is detected, the monitoring apparatus emits the signal from the microcomputer. The engine control device according to claim 1, wherein the invalidation control for the injection command and the ignition command is continued until the ignition switch is turned off. The engine control device according to claim 1 or 2, wherein the monitoring device fetches together accelerator opening information of the in-vehicle engine and generates the injection command in consideration of the fetched accelerator opening information. The engine control device according to any one of claims 1 to 3, wherein the monitoring device captures intake air amount information of the in-vehicle engine and generates the injection command in consideration of the captured intake air amount information. . The output driver extracts a current associated with the driving of each of the plurality of fuel injection valves and the plurality of ignition devices, and transfers the state of the extracted current to the monitoring device in time series as a serial signal. The monitoring device further includes a corresponding injection command or ignition command for the fuel injection valve or ignition device in which the state of the extracted current is abnormal based on the transferred serial signal. The engine control device according to any one of claims 1 to 4, wherein control for invalidating the control is executed together. The control for invalidating the injection command or the ignition command by the monitoring device is performed from the monitoring device to the output driver corresponding to the drive timing of the fuel injection valve or the ignition device in which the state of the extracted current is abnormal. The output driver inputs the injection command and the ignition command temporarily held in each stage of the shift register and the electrical input from the microcomputer in parallel. 6. The corresponding fuel injection valve and ignition device are driven based on a logical product condition of a signal obtained by a logical sum condition of an injection command and an ignition command to be performed and a logical inversion signal of the shutdown command. Engine control device. In the engine control device according to any one of claims 1 to 6,
The fuel cell further includes injection monitoring means for monitoring each energization state of the plurality of fuel injection valves, and the monitoring device also monitors the state of the fuel injection valve based on the monitored energization state. Engine control device. The engine control device according to any one of claims 1 to 7, wherein the monitoring device includes a dedicated IC. The engine control device according to any one of claims 1 to 7, wherein the monitoring device includes an auxiliary microcomputer.

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