JP5664493B2 - Abnormality judgment device for fuel pressure detection command - Google Patents

Description

  The present invention relates to a fuel pressure detection command abnormality determination device for commanding A / D conversion of fuel pressure that fluctuates with fuel injection of an internal combustion engine.

  In the common rail fuel injection system, a fuel pump pumps fuel to the common rail, and the common rail accumulates the fuel in a high pressure state. The accumulated high-pressure fuel is supplied to an injector (fuel injection valve) through a high-pressure fuel pipe provided for each cylinder of the engine (internal combustion engine). In this case, in order to perform fuel injection suitable for the operating state of the engine, a reference injection pattern suitable for each operating state is set.

  Specifically, a fuel pressure sensor that detects the fuel pressure is attached to the injector of each cylinder, and a fuel pressure detection signal that is output from the fuel pressure sensor at the time of fuel injection is A / D converted to detect the fuel pressure value, and thus the fuel pressure transition. (Learning process). In Patent Document 1, the amount of fuel injected per unit time (injection rate) is obtained from an injector based on the detected fuel pressure transition, and the injector is designed so that the injection rate transition approaches the reference injection rate transition. A fuel injection control device for giving an injection command is disclosed.

  As shown in FIG. 17, the actual engine ECU 1 includes two microcomputers, a main microcomputer 2 and a sub-microcomputer 3. The main microcomputer 2 includes a CPU 2a, an I / O port 2b, a communication interface 2c (communication I / F), a RAM (not shown), a non-volatile memory (ROM, flash memory, EEPROM), and the like. The sub microcomputer 3 includes a CPU 3a, an I / O port 3b, a communication interface 3c (communication I / F), an A / D converter 3d, a RAM (not shown), a non-volatile memory (ROM, flash memory, EEPROM), and the like. ing.

  Since the main microcomputer 2 controls the entire ECU 1 including the sub microcomputer 3, the crank angle signal (NE signal) is input to the main microcomputer 2. The main microcomputer 2 detects the angle of the crankshaft based on the crank angle signal, determines a cylinder for injecting fuel, calculates an injection start timing, an injection time, and the like, and outputs an injection signal.

  On the other hand, the sub-microcomputer 3 A / D converts the fuel pressure detection signal of the fuel injection cylinder. However, the sub-microcomputer 3 does not have the fuel injection cylinder number information because no crank angle signal is input. Therefore, as shown in FIG. 18, the main microcomputer 2 outputs, to the sub-microcomputer 3, cylinder information (cylinder numbers # 1 to # 4) indicating fuel injection cylinders and an A / D conversion start signal Q. The cylinder information is a combination of A / D conversion cylinder signals P1 and P2, and the A / D conversion start signal Q is a narrow H pulse.

  In synchronization with the A / D conversion start signal Q input to the port, the sub-microcomputer 3 learns the fuel pressure transition by sequentially A / D converting the fuel pressure detection signal output from the fuel pressure sensor of the cylinder number input to the port. This learning data is sent to the main microcomputer 2 by communication performed between the microcomputers and used for the fuel injection control described above.

JP 2009-52414 A

  For example, in the case of multistage injection in which fuel is injected multiple times from the same injector in one combustion cycle, A / D conversion is repeatedly performed in the period from the start of the first stage injection to the time point when the fuel pressure fluctuation due to the final stage injection converges There is a need to. However, in the ECU 1 described above, when the processing load of the main microcomputer 2 is large, the port output processing of the A / D conversion cylinder signals P1, P2 and the A / D conversion start signal Q is delayed or the port output processing is lost. Occurs.

  In FIG. 18, the uppermost stage is the combustion cycle of the fuel injection cylinder determined by the main microcomputer 2, and the lowermost stage is the A / D conversion implementation period of the cylinder recognized by the sub-microcomputer 3 based on the port input. In the injection of cylinder # 1, the combustion cycle coincides with the A / D conversion execution period. However, in the injection of the cylinder # 4, the start of the A / D conversion of the sub-microcomputer 3 is delayed due to the delay of the port output of the main microcomputer 2 (time td1), and there is a possibility that the fuel pressure data related to the fuel injection is missing.

  In addition, in the injection of the cylinder # 2, the process of returning the A / D conversion start signal Q to the L level is lost, and the H level continues until the process of returning to the L level for the next cylinder # 1. Therefore, the start of the A / D conversion of the cylinder # 1 is delayed until the time when the return processing to the L level is completed and a predetermined standby time has elapsed (time td2). Furthermore, since the end of the A / D conversion is delayed with respect to the injection of the cylinders # 3 and # 2, there is a possibility that fuel pressure data of a cylinder different from the fuel injection cylinder may be acquired.

  As described above, when an abnormality such as a delay occurs in the port output processing of the A / D conversion cylinder signals P1 and P2 and the A / D conversion start signal Q on the main microcomputer 2 side, the sub microcomputer 3 is delayed by that amount. To recognize the fuel injection cylinder. As a result, the combustion cycle and the A / D conversion execution period are shifted and A / D conversion cannot be performed on the wrong cylinder, or A / D conversion cannot be started.

  When the injector injects fuel, the fuel pressure detected by the fuel pressure sensor decreases. The sub-microcomputer 3 compares the number of fuel pressure drops with the number of injection stages at the end of the A / D conversion execution period, and abnormally stops the learning process if they do not match. Further, once the return processing of the A / D conversion start signal Q to the L level is lost, the start of A / D conversion for the subsequent cylinders continues to be delayed in a chain due to the influence, and it is impossible to return to the correct state. .

  On the other hand, if the load on the main microcomputer 2 is always reduced so as not to cause a delay or omission in the port output processing, the processing capacity of the microcomputer is substantially reduced. Although a method of executing the port output of the main microcomputer 2 by interrupt processing is conceivable, it is not sufficient as a solution because the processing load on the main microcomputer 2 is further increased. Therefore, load optimization processing that temporarily reduces the load on the main microcomputer 2 is necessary when the state in which the A / D conversion implementation period shifts and the learning processing becomes abnormal occurs.

  The present invention has been made in view of the above circumstances, and its purpose is to detect abnormalities in the cylinder information and A / D conversion start signal port output by the main microcomputer in order to perform the load optimization processing of the main microcomputer described above. An object of the present invention is to provide a fuel pressure detection command abnormality determination device.

  The abnormality determination device for a fuel pressure detection command described in claim 1 includes a first control device (main microcomputer) and a second control device (sub-microcomputer). The first control device commands fuel injection to each cylinder of the internal combustion engine and causes the second control device to sequentially A / D-convert the fuel pressure detection signal of the fuel pressure sensor that detects the fuel pressure that varies with fuel injection. A fuel pressure detection command including cylinder information indicating a fuel injection cylinder and an A / D conversion start signal is output to a port. The second control device inputs the cylinder information and the A / D conversion start signal from the first control device to the port, and from the time when the A / D conversion start signal is input to the port, the cylinder control unit recognizes the cylinder recognized based on the port input cylinder information. The fuel pressure detection signal is sequentially A / D converted.

  The second control device transmits the cylinder number recognized based on the cylinder information input to the port from the first control device to the first control device by communication different from the signal exchange between the ports. The first control device includes determination means for determining whether or not the cylinder number received by communication from the second control device matches the number of the fuel injection cylinder that commanded the injection by itself. As a result, the first control device confirms that the fuel injection cylinder that commanded the injection matches the recognized cylinder in which the second control device performs A / D conversion of the fuel pressure detection signal, that is, the first control device itself is the cylinder information and the A It can be determined that the / D conversion start signal is correctly output to the port. The first control device can perform load optimization processing for temporarily reducing its own load according to the abnormality determination result.

The determination means of the first control unit measures a from the time of switching the fuel injection cylinder, the recognition response time to receive the recognized cylinder number in the second control unit by the communication from the second controller. This recognition response time is the time from when the first control device switches the fuel injection cylinder until the cylinder information and A / D conversion start signal are actually output to the port, and the time required for the second control device to input the port. The time required for transmitting the cylinder number recognized by the second control device to the first control device, the time required for receiving the first control device, and the like are included.

  When the recognition response time is less than or equal to the first threshold value, the determination means of the first control device determines that the fuel pressure detection command has been made normal on the condition that the received cylinder number and the fuel injection cylinder number match. judge. When the recognition response time exceeds the first threshold value and is equal to or less than the second threshold value, it is determined that the output delay of the fuel pressure detection command is abnormal on the condition that the received cylinder number matches the fuel injection cylinder number. To do. When the recognition response time exceeds the second threshold value, it is determined that the fuel pressure detection command output is abnormal.

  Thus, if the recognition response time is determined based on the first threshold value, a delay time that is always required for port output processing and communication processing, a slight difference between the combustion cycle and the A / D conversion execution period, etc. Is no longer determined to be abnormal. In addition, if the recognition response time is determined based on the second threshold value, it is possible to determine a port output processing delay abnormality and a port output processing abnormality (for example, output omission abnormality), and return processing after abnormality determination Can be used properly according to the degree. For example, in the case of an abnormality, the processing load of the first control device is temporarily reduced. In particular, in the case of an output abnormality, the A / D conversion start signal of the first control device is reset once to recover from the abnormal output state. can do.

According to the means described in claim 2 , since there is a restriction that the communication from the second control device to the first control device is a periodic communication performed at regular intervals, the second control device can be used for port input. Accordingly, the recognized cylinder cannot be immediately transmitted to the first control device. Therefore, the second control device measures the communication standby time from when the cylinder information is input to the port until the cylinder number recognized based on the cylinder information is transmitted to the first control device by periodic communication, and the communication standby time. Is transmitted to the first control device together with the cylinder number that has been recognized.

  The determination means of the first control device sets a time obtained by subtracting the received communication waiting time from the measured recognition response time as the recognition response time, and executes the above-described determination processing. As a result, even when communication between the first control device and the second control device is not only event communication but also periodic communication, normal output, abnormal output delay, and abnormal output regarding the port output of the fuel pressure detection command The state can be judged correctly.

The abnormality determination device for a fuel pressure detection command described in claim 3 includes a first control device (main microcomputer) and a second control device (sub-microcomputer). The first control device commands fuel injection to each cylinder of the internal combustion engine and causes the second control device to sequentially A / D-convert the fuel pressure detection signal of the fuel pressure sensor that detects the fuel pressure that varies with fuel injection. A fuel pressure detection command including cylinder information indicating a fuel injection cylinder and an A / D conversion start signal is output to a port. The second control device inputs the cylinder information and the A / D conversion start signal from the first control device to the port, and from the time when the A / D conversion start signal is input to the port, The fuel pressure detection signal is sequentially A / D converted.

  The first control device monitors and inputs the signal level of the output port of cylinder information when the signal level of the output port of the A / D conversion start signal changes to a predetermined level, and the cylinder number and fuel injection based on the signal level input by the monitor Judgment means for judging whether or not the cylinder number matches is provided. As a result, the first control device correctly outputs the cylinder information indicating the fuel injection cylinder that commanded the injection and the A / D conversion start signal alone without obtaining information from the second control device through communication. It can be determined whether or not. The first control device can perform load optimization processing for temporarily reducing its own load according to the abnormality determination result.

Further , the determination unit of the first control device measures an output delay time from when the fuel injection cylinder is switched until the signal level of the output port of the A / D conversion start signal changes to a predetermined value. When the output delay time is equal to or less than the first threshold value, the determination means determines that the fuel pressure detection command has been made normally on the condition that the cylinder number based on the signal level input by the monitor matches the fuel injection cylinder number. judge. When the output delay time exceeds the first threshold value and is equal to or less than the second threshold value, the fuel pressure detection command is issued on the condition that the cylinder number based on the signal level input by the monitor matches the fuel injection cylinder number. Judged as abnormal output delay. When the output delay time exceeds the second threshold value, it is determined that the fuel pressure detection command output is abnormal.

  If the output delay time is determined based on the first threshold value in this way, it is determined that the time required for the port output processing or a slight difference between the combustion cycle and the A / D conversion implementation period is abnormal. There is no longer to do. In addition, if the output delay time is determined based on the second threshold value, it is possible to determine port output processing delay abnormality and port output processing abnormality, and use the recovery processing after abnormality determination according to the degree of abnormality. Can do. For example, in the case of an abnormality, the processing load of the first control device is temporarily reduced. In particular, in the case of an output abnormality, the A / D conversion start signal of the first control device is reset once to recover from the abnormal output state. can do.

According to the fourth aspect of the present invention, when the determination means determines that the output of the fuel pressure detection command is abnormal, the cylinder information and the A / D conversion start signal are output to the port again, and subsequently the output port of the cylinder information is output. The signal level and the A / D conversion start signal output port signal level are monitored and input. When the monitor input signal level matches the A / D conversion start signal and the cylinder number based on the monitor input signal level matches the fuel injection cylinder number, the processing load of the first control device is high. For example, it can be determined that an output omission abnormality has occurred due to omission in the port output processing. In other cases, it can be determined that the hardware itself is abnormal, that is, a port abnormality. The first control device can perform processing according to the abnormality determination result.

The abnormality determination device for the fuel pressure detection command described in claim 5 includes a first control device (main microcomputer) and a second control device (sub-microcomputer). The first control device commands fuel injection to each cylinder of the internal combustion engine and causes the second control device to sequentially A / D-convert the fuel pressure detection signal of the fuel pressure sensor that detects the fuel pressure that varies with fuel injection. A fuel pressure detection command including cylinder information indicating a fuel injection cylinder and an A / D conversion start signal is output to a port. The second control device inputs the cylinder information and the A / D conversion start signal from the first control device to the port, and from the time when the A / D conversion start signal is input to the port, The fuel pressure detection signal is sequentially A / D converted.

  The first control device transmits the fuel injection cylinder number to the second control device by communication different from the signal exchange between the ports. The second control device determines whether or not the cylinder number recognized based on the cylinder information input from the port from the first control device matches the fuel injection cylinder number received from the first control device through communication. It has. As a result, the second control device matches that the fuel injection cylinder commanded by the first control device and the recognized cylinder in which the second control device performs A / D conversion of the fuel pressure detection signal, i.e., the first control device. 1 It can be determined that the control device has correctly output the cylinder information and the A / D conversion start signal to the port. If this determination result is transmitted to the first control device, the first control device can perform load optimization processing for temporarily reducing its own load according to the abnormality determination result.

The determination means of the second control unit, the number of the fuel injection cylinder from the time of receiving the communication, to measure the command delay time of the cylinder information until port input. When the transmission waiting time by the communication of the cylinder number in the first control device is sufficiently short, the command delay time is actually the cylinder information and the A / D conversion start signal from the time when the first control device switches the fuel injection cylinder. It mainly includes the time until port output.

  When the command delay time is less than or equal to the first threshold value, the determination means of the second control device confirms that the cylinder number recognized based on the cylinder information input at the port matches the received fuel injection cylinder number. It is determined that the fuel pressure detection command is normally made as a condition. If the command delay time exceeds the first threshold value and is equal to or less than the second threshold value, the condition is that the cylinder number recognized based on the port-input cylinder information matches the received fuel injection cylinder number. It is determined that the output delay of the fuel pressure detection command is abnormal. When the command delay time exceeds the second threshold value, it is determined that the fuel pressure detection command output is abnormal.

  If the command delay time is determined based on the first threshold value in this way, it is determined that the time required for the port output processing, the slight difference between the combustion cycle and the A / D conversion implementation period, etc. are abnormal. There is no longer to do. Further, if the command delay time is determined based on the second threshold value, it is possible to determine port output processing delay abnormality and port output processing abnormality (for example, output omission abnormality), and after the abnormality determination in the first control device. The return process can be used properly according to the degree of abnormality. For example, in the case of an abnormality, the processing load of the first control device is temporarily reduced. In particular, in the case of an output abnormality, the A / D conversion start signal of the first control device is reset once to recover from the abnormal output state. can do.

The block block diagram of engine ECU which shows the 1st Embodiment of this invention Configuration diagram of common rail fuel injection system Flow chart showing abnormality determination processing of fuel pressure detection command executed by main microcomputer Timing chart of cylinder number and fuel pressure detection command showing the second embodiment of the present invention 3 equivalent figure FIG. 4 equivalent view showing the third embodiment of the present invention FIG. 1 equivalent view showing a fourth embodiment of the present invention 3 equivalent figure FIG. 4 equivalent view showing the fifth embodiment of the present invention 3 equivalent figure FIG. 9 equivalent view showing the sixth embodiment of the present invention Flow chart showing retry process executed by main microcomputer FIG. 1 equivalent view showing a seventh embodiment of the present invention Flow chart showing abnormality determination processing of fuel pressure detection command executed by sub-microcomputer FIG. 4 equivalent view showing an eighth embodiment of the present invention 14 equivalent diagram 1 equivalent diagram showing the prior art 4 equivalent diagram

(First embodiment)
Hereinafter, a first embodiment will be described with reference to FIGS. 1 to 3. The fuel pressure detection command abnormality determination device according to the present invention is applied to a fuel injection control device of an engine (internal combustion engine). Therefore, first, a common rail fuel injection system will be briefly described by taking a multi-cylinder (here, four cylinders) four-stroke, reciprocating diesel engine as an example.

  As shown in FIG. 2, the common rail fuel injection system 11 includes a fuel tank 12, a fuel pump 13, a common rail 14, an injector 15 (fuel injection valve), an ECU 16 (Electronic Control Unit), and an EDU 17 (Electronic Driving Unit). .

  The fuel pump 13 includes a high pressure pump 13 a and a low pressure pump 13 b that are driven by the power of the engine 18. The low pressure pump 13b sucks fuel through the pipe 20 provided with the fuel filter 19. The high pressure pump 13 a pressurizes the sucked fuel and pumps it to the common rail 14 through the high pressure pipe 21. An intake metering valve 13c for adjusting the fuel intake amount is provided in the fuel intake path to the pressurizing chamber of the fuel pump 13. The current flowing through the electromagnetic coil of the intake metering valve 13c is controlled by the ECU 16, and the valve body moves in accordance with the current. As a result, the fuel intake amount of the fuel pump 13 is adjusted, and as a result, the fuel discharge amount to the high-pressure pipe 21 is adjusted.

  The common rail 14 accumulates the fuel pumped from the fuel pump 13 in a high pressure state. The common rail 14 is provided with a pressure reducing valve 22 that reduces the internal fuel pressure. The pressure reducing valve 22 opens and closes according to a signal given from the ECU 16.

  The high-pressure fuel accumulated in the common rail 14 is supplied to the injector 15 through the high-pressure fuel pipe 23. The injector 15 injects fuel into the combustion chambers of the cylinders # 1 to # 4 of the engine 18 at a predetermined timing by a drive signal given from the EDU 17. One combustion cycle with four strokes of suction, compression, combustion, and exhaust for each cylinder # 1 to # 4 is executed in order of cylinders # 1, # 3, # 4, and # 2 by 180 ° CA.

A fuel pressure sensor 24 for detecting a fuel pressure (fuel pressure) is attached to the fuel intake port of each injector 15. The ECU 16 can detect (learn) the change waveform of the fuel pressure associated with the injection operation of the injector 15 by taking the fuel pressure detection signal output from the fuel pressure sensor 24 after A / D conversion.
The fuel leaked from the fuel pump 13, the fuel released from the pressure reducing valve 22 of the common rail 14, and the fuel released from the hydraulic chamber of the injector 15 are returned to the fuel tank 12 through the return passage 25.

  FIG. 1 shows the configuration of the ECU 16. The ECU 16 is composed mainly of a main microcomputer 27 (first control device) and a sub-microcomputer 28 (second control device), and forms a fuel injection control device and a fuel pressure detection command abnormality determination device. The main microcomputer 27 includes a CPU 27a (determination means), an I / O port 27b, a communication interface 27c (communication I / F), a timer 27d, a RAM (not shown), a nonvolatile memory (ROM, flash memory, or EEPROM), and the like. ing.

  The sub-microcomputer 28 includes a CPU 28a, an I / O port 28b, a communication interface 28c (communication I / F), a timer 28d, an A / D converter 28e, a RAM (not shown), and a non-volatile memory (ROM, flash memory, or EEPROM). Etc. The communication interfaces 27c and 28c are configured by, for example, a UART (Universal Asynchronous Receiver Transmitter), but may be configured by a DMA controller or a CAN (Controller Area Network) controller.

  In FIG. 1, the “recognized cylinder number” and the “fuel injection cylinder number” described in the main microcomputer 27 and the “recognized cylinder number” described in the sub microcomputer 28 are the main microcomputer 27 and the sub microcomputer, respectively. Reference numeral 28 denotes a cylinder number as data. In addition, arrows attached to these conceptually indicate the flow of data.

  The main microcomputer 27 executes a control program stored in a non-volatile memory, thereby performing a crank angle signal (NE signal), an engine coolant temperature detection signal, a fuel temperature detection signal, an accelerator opening signal, and other various sensors. A signal is input to grasp the operating state of the engine 18. Then, based on the grasped operating state of the engine 18, the fuel supply control to the common rail 14 by the fuel pump 13 is performed, the fuel injection cylinder for injecting the fuel is determined, and the fuel injection start timing for the fuel injection cylinder Then, fuel injection control for calculating an injection time and outputting an injection signal to the EDU 17 at an accurate timing is performed. In this case, a reference injection pattern suitable for each operation state of the engine 18 is stored in a nonvolatile memory as a map or a mathematical expression, and an optimum fuel injection pattern is set with reference to this map or mathematical expression in an actual operation state. .

  Further, the main microcomputer 27 acquires fuel pressure (fuel pressure) that fluctuates with the injection of the injector 15, so that A / D conversion cylinder signals P <b> 1 and P <b> 2 indicating fuel injection cylinders to the sub-microcomputer 28 at the start of each combustion cycle. A fuel pressure detection command consisting of (corresponding to cylinder information) and an A / D conversion start signal Q is output to the port, and the sub-microcomputer 28 A / D converts the fuel pressure detection signal output from the fuel pressure sensor 24.

  Cylinder numbers # 1 to # 4 are represented by combinations of A / D conversion cylinder signals P1 and P2. When (P1, P2) = (0, 0), cylinder number # 1, when (P1, P2) = (1, 1), cylinder number # 2, (P1, P2) = (1, 0) Represents cylinder number # 3, and (P1, P2) = (0, 1) represents cylinder number # 4. The A / D conversion start signal Q is composed of a narrow H pulse. However, as described above, when the processing load of the main microcomputer 27 increases, the port output processing of the A / D conversion cylinder signals P1, P2 and the A / D conversion start signal Q may be delayed or the port output processing may be lost. is there.

  On the other hand, the sub-microcomputer 28 inputs the A / D conversion cylinder signals P1 and P2 and the A / D conversion start signal Q by executing a control program stored in the nonvolatile memory. Specifically, an interrupt is generated at the rising edge of the A / D conversion start signal Q, and the A / D conversion cylinder signals P1 and P2 are input to the port in the interrupt process. The cylinder number is recognized based on the A / D conversion cylinder signals P1 and P2 input to the port, and the recognized cylinder number is immediately transmitted to the main microcomputer 27 by communication.

  At the same time, the sub-microcomputer 28 sequentially outputs the fuel pressure detection signal output from the fuel pressure sensor 24 of the recognized cylinder at an interval of, for example, 10 μsec from the time when the input A / D conversion start signal Q rises from the L level to the H level. / D conversion to acquire (learn) fuel pressure transition. The A / D conversion execution interval is set to be equal to or shorter than the time interval at which the waveform of the fuel pressure transition can be correctly recognized.

  When the injector 15 injects fuel, the fuel pressure of the cylinder tends to increase after rapidly decreasing. The sub-microcomputer 28 detects the number of stages of multistage injection (the number of injections in one combustion cycle) based on the fuel pressure transition waveform obtained by A / D conversion, and whether the number of detected stages matches the number of injection stages of the fuel injection pattern. Determine whether or not. The number of injection stages of the fuel injection pattern is transmitted from the main microcomputer 27 to the sub-microcomputer 28 by communication.

  If they match as a result of the determination, the acquired learning data of the fuel pressure transition is transmitted to the main microcomputer 27 by communication. This learning data is used in the fuel injection control described above in the main microcomputer 27. On the other hand, in the case of mismatch, there is a difference between the combustion cycle of the fuel injection cylinder and the A / D conversion execution period, or the fuel injection cylinder and the A / D conversion execution cylinder are different. Therefore, the sub-microcomputer 28 stops the fuel pressure data learning process.

  FIG. 3 shows a fuel pressure detection command abnormality determination process executed by the CPU 27a of the main microcomputer 27. The main microcomputer 27 outputs the A / D conversion cylinder signals P1, P2 indicating the fuel injection cylinder and the A / D conversion start signal Q from the I / O port 27b, and then transmits the cylinder number recognized by the sub microcomputer 28 to the communication I / O. Received from the sub-microcomputer 28 via F27c (step S1).

  The main microcomputer 27 determines whether or not the received recognition cylinder number and fuel injection cylinder number of the sub-microcomputer 28 match (step S2). If it is determined that they match (YES), the sub-microcomputer 28 correctly recognizes the fuel injection cylinder sent from the main microcomputer 27 and correctly converts the fuel pressure detection signal of that cylinder to A / D, so the output is normal. The state is determined (step S3).

  On the other hand, if it is determined in step S2 that they do not match (NO), the sub-microcomputer 28 does not correctly recognize the fuel injection cylinder sent from the main microcomputer 27, so it is determined that the output is abnormal (step S4). This may be because the processing load of the main microcomputer 27 is increased and the port output process of the fuel pressure detection command is delayed or the port output process is lost.

  In this case, the main microcomputer 27 executes a process for returning to the normal output state (step S5). This return process is a load optimization process that temporarily reduces the processing load of the main microcomputer 27, for example. If the abnormal output state is repeated, the A / D conversion start signal Q output from the port may be reset to L level. By these processes, the recognition cylinder of the sub-microcomputer 28 and the fuel injection cylinder come to coincide.

  As described above, the ECU 16 of the present embodiment includes the main microcomputer 27 and the sub microcomputer 28. The sub microcomputer 28 receives the cylinder fuel pressure detection signal recognized based on the fuel pressure detection command output from the main microcomputer 27 at the port. A / D conversion is performed. In this case, the sub-microcomputer 28 transmits the number of the recognized cylinder to the main microcomputer 27 by communication different from the signal transmission / reception between the ports, so that the main microcomputer 27 matches the fuel injection cylinder and the recognized cylinder of the sub-microcomputer 28? It can be determined whether or not.

  If they do not match, the port output of the fuel pressure detection command is delayed in the main microcomputer 27 or the process is missing, so the main microcomputer 27 may execute a return process (load optimization process, reset process). it can. Thereby, it is possible to recover from the stop of learning of the fuel pressure data due to the mismatch between the combustion cycle and the A / D conversion implementation period, and it is possible to learn the correct fuel pressure and its transition for each combustion cycle.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. 4 and 5. This embodiment has the same hardware configuration as that of the first embodiment (see FIG. 1), and the port output abnormality of the main microcomputer 27 is different from the fuel pressure detection command abnormality determination processing described in the first embodiment. The state can be discriminated into two types. The communication I / Fs 27c and 28c used here are capable of event communication.

  FIG. 4 is a timing chart of a cylinder number and a fuel pressure detection command. In order from the top, the cylinder recognized by the sub-microcomputer 28 based on the A / D conversion cylinder signals P1 and P2 input to the port, the recognized cylinder of the sub-microcomputer 28 received by the main microcomputer 27, and the fuel injection cylinder determined by the main microcomputer 27 sequentially , A / D conversion start signal Q and A / D conversion cylinder signals P1 and P2.

  Although the main microcomputer 27 switches the fuel injection cylinder from # 3 to # 4 at time t1, the port output processing is delayed because the processing load on the main microcomputer 27 is large, and a fuel pressure detection command (A / D conversion cylinder) is detected at time t2. The signals P1 and P2 and the A / D conversion start signal Q) are output to the port. The sub-microcomputer 28 immediately transmits the cylinder number # 4 recognized based on the A / D conversion cylinder signals P1 and P2 input to the port to the main microcomputer 27 by communication. However, the sub-microcomputer 28 takes time for transmission / reception processing by the communication I / Fs 27c and 28c. Therefore, the main microcomputer 27 receives the recognized cylinder number # 4 of the sub-microcomputer 28 at time t3.

  FIG. 5 shows a fuel pressure detection command abnormality determination process executed by the CPU 27 a of the main microcomputer 27. The timer 27d of the main microcomputer 27 recognizes the response time from when the fuel injection cylinder is switched (time t1, t5,...) Until the recognized cylinder number is received from the sub-microcomputer 28 by communication (time t3,...). Measure ta.

  The main microcomputer 27 determines whether or not the measured recognition response time ta is equal to or shorter than the first threshold value tp1 (within the normal time) (step S11). The first threshold value tp1 is inevitably necessary regardless of the processing load of the main microcomputer 27, the port output processing time of the main microcomputer 27, the port input processing time of the sub-microcomputer 28, and the transmission processing time of the sub-microcomputer 28. In addition, the time is set to a time that is longer than the total reception processing time of the main microcomputer 27 and does not include a delay in port output processing due to a large processing load on the main microcomputer 27.

  If it is determined that the time is within normal time (YES), it is determined whether or not the received numbers of the recognized cylinder and the fuel injection cylinder of the sub-microcomputer 28 match (step S12). When it is determined that they match (YES), the fuel pressure detection command is normally sent from the main microcomputer 27 to the sub-microcomputer 28 without delay due to the processing load, and the sub-microcomputer 28 selects the fuel injection cylinder sent from the main microcomputer 27. Since it is recognized correctly, it is determined that the output is normal (step S13). If it is determined in step S12 that there is a mismatch (NO), the process returns to step S11.

  On the other hand, if it is determined in step S11 that it is not within the normal time (NO), it is determined whether or not the measured recognition response time ta is equal to or less than the second threshold value tp2 (within the delay abnormal time) (step S14). The second threshold value tp2 is set to an upper limit value of a delay time that can be evaluated as a delay in port output due to a large processing load on the main microcomputer 27. For example, this is the delay time of cylinder # 4 shown in FIG. When the recognition response time ta exceeds the second threshold value tp2, the output from which the port output processing (for example, the falling processing of the A / D conversion start signal Q) is omitted is performed as in cylinder # 2 shown in FIG. This is a missing error (equivalent to an output error) and can be distinguished from an output delay error.

  If the main microcomputer 27 determines in step S14 that it is within the delay abnormality time (YES), it determines whether or not the recognized cylinder number and fuel injection cylinder number of the received sub-microcomputer 28 match (step S15). If it is determined that they coincide with each other (YES), it is determined that the port output process of the fuel pressure detection command is delayed because the processing load of the main microcomputer 27 is large (step S16), and the process for returning to the normal output state is performed. Is executed (step S17). This return process is a load optimization process that temporarily reduces the load on the main microcomputer 27, for example. This return process eliminates the output delay abnormality. If it is determined that there is a mismatch (NO) in step S15, the process returns to step S11.

  If the main microcomputer 27 determines that it is not within the delay abnormality time (NO) in step S14, it determines that the output pressure is abnormal because the processing load is large and the port output processing of the fuel pressure detection command is lost (step S18), and the port output. The reset process is executed (step S19). The reset process is a process for removing the A / D conversion start signal Q from the state in which the start of A / D conversion for the fuel injection cylinders that are sequentially switched continues to be delayed in a chain manner, for example, by forcibly returning the A / D conversion start signal Q to the L level. Thereafter, a return process similar to step S17 is executed (step S20). This return processing eliminates the output omission abnormality.

  According to the present embodiment, the main microcomputer 27 measures the recognition response time ta from when the fuel injection cylinder is switched to when the recognized cylinder number of the sub-microcomputer 28 is received, and according to the recognition response time ta, the fuel pressure With regard to the detection command port output, it is possible to determine the normal output state, abnormal output delay state, and abnormal output loss state.

  If the recognition response time ta is determined on the basis of the first threshold value tp1, the delay time, which is necessary for the port input / output processing and communication processing, and the fuel pressure detection processing between the combustion cycle and the A / D conversion implementation period are used. It is no longer necessary to judge a slight difference that has no effect as abnormal. If the recognition response time ta is determined based on the second threshold value tp2, the port output process delay abnormality and the port output process omission abnormality can be determined. In the latter case, the reset process is executed. It is possible to escape from a continuous output loss abnormal state.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. This embodiment also uses a fuel pressure detection command abnormality determination method that can determine two types of abnormal states of the port output of the main microcomputer 27 as in the second embodiment. However, unlike the second embodiment, the communication I / Fs 27c and 28c perform regular communication at regular intervals.

  FIG. 6 is a timing chart of the cylinder number and fuel pressure detection command shown in the same manner as FIG. The main microcomputer 27 switches the fuel injection cylinder from # 3 to # 4 at time t11. However, since the processing load is large, the main microcomputer 27 delays until time t13 and outputs a fuel pressure detection command to the port. Similarly to the second embodiment, from the time when the fuel injection cylinder is switched (time t11, t16,...) Until the recognized cylinder number is received from the sub-microcomputer 28 by communication (time t15,...). The recognition response time ta is measured.

  The sub-microcomputer 28 inputs a fuel pressure detection command at time t13 and recognizes the cylinder number # 4 based on the A / D conversion cylinder signals P1 and P2. However, since it is not event communication as in the second embodiment, it cannot be transmitted immediately, and the recognized cylinder number is transmitted to the main microcomputer 27 after waiting for the next regular communication timing (time t15). Therefore, the sub-microcomputer 28 measures the communication standby time tb from when the fuel pressure detection command is input to the port until the recognized cylinder number is transmitted to the main microcomputer 27 by the timer 28d, and communicates with the recognized cylinder number at the next regular communication timing. The standby time tb is transmitted to the main microcomputer 27.

  When the main microcomputer 27 receives the recognized cylinder number and the communication standby time tb from the sub-microcomputer 28, the main microcomputer 27 sets the time obtained by subtracting the communication standby time tb from the recognition response time ta as the recognition response time ta. The abnormality determination process of the fuel pressure detection command shown in FIG. According to the present embodiment, even when communication between the main microcomputer 27 and the sub-microcomputer 28 is regular communication, the output normal state, the output delay abnormal state, and the output omission abnormal state (output abnormality) for the port output of the fuel pressure detection command Status) can be determined correctly.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIGS. The abnormality determination device for the fuel pressure detection command of the present embodiment is similarly applied to the engine fuel injection control device shown in FIG. The ECU 16 has the same hardware configuration as that shown in FIG. 1 as shown in FIG. 7, and the processes of the main microcomputer 27 and the sub-microcomputer 28 are the same as those in the first embodiment except for the abnormality determination process of the fuel pressure detection command. Yes.

  That is, the main microcomputer 27 inputs various sensor signals to grasp the operating state of the engine 18 and performs fuel supply control and fuel injection control based on the grasped operation state. Further, in order to obtain the fuel pressure (fuel pressure) that fluctuates with the injection of the injector 15, A / D conversion cylinder signals P1 and P2 indicating the fuel injection cylinder to the sub-microcomputer 28 at the start of each combustion cycle and A / D conversion. A fuel pressure detection command including the start signal Q is output to the port. However, if the processing load of the main microcomputer 27 increases, the port output process of the fuel pressure detection command may be delayed or the port output process may be lost.

  On the other hand, the sub-microcomputer 28 inputs the A / D conversion cylinder signals P1 and P2 and the A / D conversion start signal Q into ports. Then, the cylinder number is recognized based on the A / D conversion cylinder signals P1 and P2 input to the port. However, unlike the first embodiment, the recognized cylinder number is not transmitted to the main microcomputer 27. The sub-microcomputer 28 sequentially A / D-converts the fuel pressure detection signal output from the fuel pressure sensor 24 of the recognized cylinder to acquire the fuel pressure transition from the time when the input A / D conversion start signal Q rises to H level ( learn. The sub-microcomputer 28 compares the number of stages of multi-stage injection detected based on the fuel pressure transition waveform and the number of injection stages of the fuel injection pattern, and if they match, the acquired learning data of the fuel pressure transition is communicated to the main microcomputer 27 by communication. Send. If they do not match, the fuel pressure data learning process is stopped.

  FIG. 8 shows a fuel pressure detection command abnormality determination process executed by the CPU 27 a of the main microcomputer 27. When the main microcomputer 27 determines the fuel injection cylinder and outputs an injection signal to the EDU 17, the main microcomputer 27 executes the port output process of the fuel pressure detection command. However, as described above, the port output process has a delay or omission depending on the processing load. May occur. Therefore, the main microcomputer 27 performs port input (monitor input) for the signal levels of the output ports of the A / D conversion cylinder signals P1, P2 and the A / D conversion start signal Q (step S21). This monitor input timing is when the signal level of the output port of the A / D conversion start signal Q rises from L level to H level.

  In the main microcomputer 27, the signal level of the output port of the A / D conversion start signal Q input to the monitor is correctly set to the H level, and the signal level of the output port of the A / D conversion cylinder signals P1 and P2 input to the monitor is set. It is determined whether or not the base cylinder number and the fuel injection cylinder number match (step S22). When it is determined that they match (YES), the main microcomputer 27 correctly outputs the port of the fuel injection cylinder, so the sub-microcomputer 28 correctly recognizes the fuel injection cylinder sent from the main microcomputer 27 and detects the fuel pressure of that cylinder. Therefore, it is determined that the output is normal (step S23).

  On the other hand, if it is determined in step S22 that they do not match (NO), the main microcomputer 27 does not correctly output the fuel pressure detection command, and the sub-microcomputer 28 does not correctly recognize the fuel injection cylinder sent from the main microcomputer 27. It is determined that the output is abnormal (step S24). As a cause of this, it is conceivable that the processing load on the main microcomputer 27 is large. Therefore, the main microcomputer 27 executes the return processing to the normal output state in the same manner as step S5 shown in FIG. 3 (step S25).

  As described above, the main microcomputer 27 of the present embodiment monitors and inputs the signal level of the output port of the fuel pressure detection command after the port output processing of the fuel pressure detection command. It can be determined whether or not the number of the fuel injection cylinder matches. As a result, the main microcomputer 27 determines whether or not the A / D conversion cylinder signals P1 and P2 and the A / D conversion start signal Q are correctly output to the port independently without obtaining the recognized cylinder number by communication from the sub-microcomputer 28. Can be confirmed. In the case of inconsistency, the return processing (load optimization processing, reset processing) is executed in the same manner as in the first embodiment, so that the learning of fuel pressure data is stopped due to inconsistency between the combustion cycle and the A / D conversion execution period. It is possible to recover and learn the correct fuel pressure and its transition for each combustion cycle.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIGS. 9 and 10. This embodiment has the same hardware configuration as that of the fourth embodiment (see FIG. 7), and the port output abnormality of the main microcomputer 27 is different from the fuel pressure detection command abnormality determination processing described in the fourth embodiment. The state can be discriminated into two types.

  FIG. 9 is a timing chart of a cylinder number and a fuel pressure detection command. In order from the top, the fuel injection cylinder sequentially determined by the main microcomputer 27, the cylinder number based on the signal level monitored by the main microcomputer 27, the A / D conversion start signal Q, and the A / D conversion cylinder signals P1 and P2 are shown. .

  Although the main microcomputer 27 switches the fuel injection cylinder from # 3 to # 4 at time t21, the port output processing is delayed because the processing load on the main microcomputer 27 is large, and a fuel pressure detection command (A / D conversion cylinder) at time t23. The signals P1 and P2 and the A / D conversion start signal Q) are output to the port. The sub-microcomputer 28 recognizes the cylinder number # 4 based on the A / D conversion cylinder signals P1 and P2 input to the port, and performs A / D conversion on the fuel pressure detection signal output from the fuel pressure sensor 24 of the recognized cylinder to generate fuel. Acquire (learn) the pressure transition.

  FIG. 10 shows a fuel pressure detection command abnormality determination process executed by the CPU 27a of the main microcomputer 27. The timer 27d of the main microcomputer 27 starts when the signal level of the output port of the A / D conversion start signal Q rises from L level to H level from the time when the fuel injection cylinder is switched (time t21, t25,...). The output delay time tc until t23,.

  The main microcomputer 27 determines whether or not the measured output delay time tc is equal to or less than the first threshold value tq1 (within the normal time) (step S31). The first threshold value tq1 is longer than the port output processing time of the main microcomputer 27 that is inevitably necessary regardless of the processing load of the main microcomputer 27, and the port output due to the large processing load of the main microcomputer 27. It is set to a time that does not include processing delays.

  If it is determined that the time is within the normal time (YES), the main microcomputer 27 indicates that the signal level of the output port of the A / D conversion start signal Q input to the monitor is correctly H level, and the A / D conversion input to the monitor is input. It is determined whether or not the cylinder number based on the signal level at the output port of the cylinder signals P1 and P2 matches the number of the fuel injection cylinder (step S32). If YES is determined here, the fuel pressure detection command is normally output from the main microcomputer 27 to the sub-microcomputer 28 without delay due to the processing load, and the sub-microcomputer 28 correctly recognizes the fuel injection cylinder sent from the main microcomputer 27. Therefore, the normal output state is determined (step S33). If NO is determined in step S32, the process returns to step S31.

  On the other hand, if it is determined in step S31 that it is not within the normal time (NO), it is determined whether or not the measured output delay time tc is less than or equal to the second threshold value tq2 (within the delay abnormal time) (step S34). The second threshold value tq2 is set to an upper limit value of a delay time that can be evaluated as a port output delay due to a large processing load on the main microcomputer 27. For example, this is the delay time of cylinder # 4 shown in FIG. When the output delay time tc exceeds the second threshold value tp2, the output from which the port output processing (for example, the falling processing of the A / D conversion start signal Q) is omitted is performed as in the cylinder # 2 shown in FIG. This is a disconnection abnormality or an I / O port 27b abnormality (corresponding to an output abnormality), and can be distinguished from an output delay abnormality.

  If the main microcomputer 27 determines that it is within the delay abnormal time (YES) in step S34, the main microcomputer 27 executes the same determination processing as step S32 (step S15). If YES is determined here, it is determined that the port output process of the fuel pressure detection command is delayed because the processing load of the main microcomputer 27 is large (step S36), and the process of returning to the normal output state is executed (step S36). Step S37). This return process is a load optimization process that temporarily reduces the load on the main microcomputer 27, for example. This return process eliminates the output delay abnormality. If NO is determined in step S35, the process returns to step S31.

  If the main microcomputer 27 determines that it is not within the delay abnormality time (NO) in step S34, it is determined that the output omission abnormal state in which the port output process of the fuel pressure detection command is lost due to a large processing load or the I / O port 27b is abnormal. (Step S38), and a port output reset process is executed (Step S39). The reset process is the same as step S19 shown in FIG. Thereafter, a return process similar to step S37 is executed (step S40). This process eliminates the output abnormality.

  According to the present embodiment, the main microcomputer 27 measures the output delay time tc from when the fuel injection cylinder is switched until the signal level of the output port of the A / D conversion start signal Q rises, and the output delay time tc. Accordingly, the normal output state, abnormal output delay state, and abnormal output state can be determined for the port output of the fuel pressure detection command.

  If the output delay time tc is determined based on the first threshold value tq1, the delay time that is always required for the port output processing and the fuel pressure detection processing between the combustion cycle and the A / D conversion execution period are not affected. It is not determined that a slight difference or the like is abnormal. Further, if the output delay time tc is determined based on the second threshold value tq2, it is possible to determine a port output processing delay abnormality and other output abnormalities.

(Sixth embodiment)
Next, a sixth embodiment will be described with reference to FIGS. 11 and 12. In the present embodiment, processing for determining the cause of the output abnormality is added to step S38 in the fifth embodiment.

  FIG. 11 is a timing chart of the cylinder number and the fuel pressure detection command represented on the time axis common to FIG. The cylinder based on the monitor input is omitted. When the output delay time tc exceeds the second threshold value tq2 (time t24), the main microcomputer 27 determines that the output is abnormal (step S38 shown in FIG. 10). At this time, the main microcomputer 27 additionally executes a retry process shown in FIG.

  The main microcomputer 27 outputs the fuel pressure detection command composed of the A / D conversion cylinder signals P1 and P2 and the A / D conversion start signal Q again to the port (step S41), and subsequently the A / D conversion cylinder signals P1 and P2. The A / D conversion start signal Q is input to the port (monitor input) (step S42). The main microcomputer 27 determines whether the signal output from the port matches the signal input to the monitor, in other words, the signal level of the output port of the A / D conversion start signal Q input to the monitor is correctly H level, and It is determined whether or not the cylinder number based on the signal level of the output port of the A / D conversion cylinder signals P1 and P2 input by the monitor coincides with the number of the fuel injection cylinder (step S43).

  If YES is determined here, the I / O port 27b is operating normally, and it is determined that the output omission abnormal state in which the port output process of the fuel pressure detection command is omitted because the processing load of the main microcomputer 27 is large (step S44). ). On the other hand, if NO is determined, the I / O port 27b is determined to be in an I / O port abnormal state in which the port output process of the fuel pressure detection command is omitted due to the abnormality (step S45).

  According to this embodiment, when the fuel pressure detection command is not output from the main microcomputer 27, it is possible to determine whether an output omission abnormality due to a large processing load or an I / O port abnormality due to a failure of the I / O port 27b. . Thereby, the main microcomputer 27 can execute a process according to the abnormality determination result, for example, a diagnosis signal output process.

(Seventh embodiment)
Next, a seventh embodiment will be described with reference to FIGS. 13 and 14. The abnormality determination device for the fuel pressure detection command of the present embodiment is similarly applied to the engine fuel injection control device shown in FIG. The ECU 16 has the same hardware configuration as that of FIG. 1 as shown in FIG. 13, and the processing of the main microcomputer 27 and the sub-microcomputer 28 is also common to the first embodiment except for the abnormality determination processing of the fuel pressure detection command. Yes. In the present embodiment, the CPU 28a of the sub-microcomputer 28 corresponds to the determination unit.

  That is, the main microcomputer 27 inputs various sensor signals to grasp the operating state of the engine 18 and performs fuel supply control and fuel injection control based on the grasped operation state. Further, in order to obtain the fuel pressure (fuel pressure) that fluctuates with the injection of the injector 15, A / D conversion cylinder signals P1 and P2 indicating the fuel injection cylinder to the sub-microcomputer 28 at the start of each combustion cycle and A / D conversion. A fuel pressure detection command including the start signal Q is output to the port. However, if the processing load on the main microcomputer 27 increases, the port output process of the fuel pressure detection command may be delayed or the port output process may be lost.

  On the other hand, the sub-microcomputer 28 inputs the A / D conversion cylinder signals P1 and P2 and the A / D conversion start signal Q into ports. Then, the cylinder number is recognized based on the A / D conversion cylinder signals P1 and P2 input to the port. However, unlike the first embodiment, the recognized cylinder number is not transmitted to the main microcomputer 27, but the number of the fuel injection cylinder is transmitted from the main microcomputer 27 to the sub-microcomputer 28 by communication.

  The sub-microcomputer 28 sequentially A / D-converts the fuel pressure detection signal output from the fuel pressure sensor 24 of the recognized cylinder to acquire the fuel pressure transition from the time when the input A / D conversion start signal Q rises to H level ( learn. The sub-microcomputer 28 compares the number of stages of multi-stage injection detected based on the fuel pressure transition waveform and the number of injection stages of the fuel injection pattern, and if they match, the acquired learning data of the fuel pressure transition is communicated to the main microcomputer 27 by communication. Send. If they do not match, the fuel pressure data learning process is stopped.

  FIG. 14 shows a fuel pressure detection command abnormality determination process executed by the CPU 28a of the sub-microcomputer 28. When the main microcomputer 27 determines the fuel injection cylinder and outputs an injection signal to the EDU 17, the main microcomputer 27 outputs a fuel pressure detection command via the I / O port 27b and transmits it to the sub-microcomputer 28 via the communication I / F 27c. To do. Although transmission processing does not cause delays or omissions, port output processing may cause delays or omissions according to the processing load as described above.

  The sub-microcomputer 28 receives the cylinder number indicating the fuel injection cylinder via the communication I / F 28c (step S51), and receives the A / D conversion cylinder signals P1, P2 and the A / D conversion start signal Q through the I / O port 28b. Is input to the port (step S52). The sub-microcomputer 28 recognizes the cylinder number based on the A / D conversion cylinder signals P1 and P2 input to the port, and determines whether or not the recognized cylinder number matches the received cylinder number (step S53). If it is determined that they match (YES), the sub-microcomputer 28 correctly recognizes the fuel injection cylinder and correctly converts the fuel pressure detection signal of that cylinder to A / D conversion, so it is determined that the output is normal (step S54). ).

  On the other hand, if it is determined in step S53 that they do not match (NO), the sub-microcomputer 28 does not correctly recognize the fuel injection cylinder output from the main microcomputer 27, and therefore determines that the output is abnormal (step S55). As this cause, it is conceivable that the processing load of the main microcomputer 27 is large. Therefore, the sub-microcomputer 28 transmits the determination result to the main microcomputer 27 (step S56). Based on this determination result, the main microcomputer 27 performs a return process (load optimization process, reset process) to a normal output state.

  As described above, the main microcomputer 27 of the present embodiment outputs a fuel pressure detection command to the sub-microcomputer 28 through a port and transmits the number of the fuel injection cylinder by communication such as UART. The sub-microcomputer 28 can detect that the main microcomputer 27 does not correctly output the fuel pressure detection command when the cylinder number recognized based on the cylinder information input through the port does not match the received cylinder number.

  If they do not match, the main microcomputer 27 transmits a determination result from the sub-microcomputer 28 to the main microcomputer 27, so that the main microcomputer 27 executes a return process (load optimization process, reset process) as in the first embodiment. Therefore, it is possible to return from the stop of learning of the fuel pressure data due to the mismatch between the combustion cycle and the A / D conversion implementation period.

(Eighth embodiment)
Next, an eighth embodiment will be described with reference to FIGS. 15 and 16. This embodiment has the same hardware configuration as that of the seventh embodiment (see FIG. 13), and the port output abnormality of the main microcomputer 27 is different from the fuel pressure detection command abnormality determination process described in the seventh embodiment. The state can be discriminated into two types.

  FIG. 15 is a timing chart of a cylinder number and a fuel pressure detection command. In order from the top, the cylinder number recognized by the sub-microcomputer 28 based on the A / D conversion cylinder signals P1 and P2 input to the port, the cylinder number received by the sub-microcomputer 28 through communication, the fuel injection cylinder sequentially determined by the main microcomputer 27, An A / D conversion start signal Q and A / D conversion cylinder signals P1 and P2 are shown.

  The main microcomputer 27 switches the fuel injection cylinder from # 3 to # 4 at time t31 and transmits the fuel injection cylinder number, and the sub-microcomputer 28 receives the cylinder number at time t32. On the other hand, because the processing load of the main microcomputer 27 is large, the port output processing is delayed, and the sub-microcomputer 28 ports the fuel pressure detection command (A / D conversion cylinder signals P1, P2 and A / D conversion start signal Q) at time t34. You are typing.

  FIG. 16 shows a fuel pressure detection command abnormality determination process executed by the CPU 28 a of the sub-microcomputer 28. The timer 28d of the sub-microcomputer 28 receives the fuel pressure detection command (A / D conversion cylinder signals P1, P2 and A / D conversion start signal Q) from the time when the cylinder number is received from the main microcomputer 27 (time t32). The command delay time td until the port is input is measured.

  The sub-microcomputer 28 determines whether or not the measured command delay time td is equal to or less than the first threshold value tr1 (within the normal time) (step S61). The first threshold value tr1 is the port output processing time of the main microcomputer 27 that is inevitably necessary regardless of the processing load of the main microcomputer 27 (more precisely, the time obtained by subtracting the transmission processing time of the main microcomputer 27 from now on) ) And the total port input processing time of the sub-microcomputer 28, and a time that does not include a delay in port output processing due to a large processing load on the main microcomputer 27.

  If it is determined that it is within normal time (YES), the sub-microcomputer 28 determines whether or not the cylinder number recognized based on the A / D conversion cylinder signals P1 and P2 input to the port matches the received cylinder number. (Step S62). When it is determined that they match (YES), the fuel pressure detection command is normally output from the main microcomputer 27 to the sub-microcomputer 28 without delay due to the processing load, and the sub-microcomputer 28 correctly recognizes the fuel injection cylinder, and the cylinder Since the fuel pressure detection signal is correctly A / D converted, it is determined that the output is normal (step S63). If NO is determined in step S62, the process returns to step S61.

  On the other hand, if it is determined in step S61 that it is not within the normal time (NO), it is determined whether or not the measured command delay time td is equal to or less than the second threshold value tr2 (within the delay abnormal time) (step S64). The second threshold value tr2 is set to an upper limit value of a delay time that can be evaluated as a port output delay due to a large processing load on the main microcomputer 27. For example, this is the delay time of cylinder # 4 shown in FIG. When the command delay time td exceeds the second threshold value tr2, the output from which the port output processing (for example, the falling processing of the A / D conversion start signal Q) is omitted is performed as in cylinder # 2 shown in FIG. This is a missing error (equivalent to an output error) and can be distinguished from an output delay error.

  If the sub-microcomputer 28 determines in step S64 that it is within the delay abnormality time (YES), it determines whether or not the recognized cylinder number matches the received cylinder number (step S65). If it is determined that they match (YES), it is determined that there is an output delay abnormality state in which the port output processing of the fuel pressure detection command is delayed because the processing load of the main microcomputer 27 is large (step S66). If it is determined that there is a mismatch (NO) in step S65, the process returns to step S61.

  If the sub-microcomputer 28 determines that it is not within the delay abnormality time (NO) in step S64, it determines that the output omission abnormality state in which the port output process of the fuel pressure detection command is lost due to a large processing load (step S67). If it is determined as an abnormal state, the determination result is transmitted to the main microcomputer 27 (step S68). Based on this determination result, the main microcomputer 27 performs a return process (load optimization process, reset process) to a normal output state.

  According to this embodiment, the sub-microcomputer 28 measures the command delay time td from when the cylinder number is received from the main microcomputer 27 until the sub-microcomputer 28 inputs the fuel pressure detection command to the port, and the command delay time td Accordingly, the normal output state, abnormal output delay state, and abnormal output loss state can be determined for the port output of the fuel pressure detection command.

  If the command delay time td is determined based on the first threshold value tr1, the delay time that is always required for the port output process, and the fuel pressure detection process between the combustion cycle and the A / D conversion execution period are not affected. It is not determined that a slight difference or the like is abnormal. Further, if the command delay time td is determined based on the second threshold value tr2, it is possible to determine a port output process delay abnormality and a port output process omission abnormality.

(Other embodiments)
As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment mentioned above, A various deformation | transformation and expansion | extension can be performed within the range which does not deviate from the summary of invention.
Although the fuel pressure sensor 24 is attached to the fuel intake port of the injector 15, the attachment position can be appropriately changed, for example, attached to the high-pressure fuel pipe 23 connecting the common rail 14 and the injector 15.

  The A / D conversion period of the fuel pressure detection signal may be a period from the start of the first stage injection of at least one combustion cycle to the time when the fuel pressure fluctuation due to the final stage of injection converges. Accordingly, the main microcomputer 27 may be configured to output the fuel pressure detection command at the reference time set between the start of each combustion cycle and the start of the first stage injection, instead of at the start of each combustion cycle.

  In the drawing, 18 is an engine (internal combustion engine), 24 is a fuel pressure sensor, 27 is a main microcomputer (first control device), 27a is a CPU (determination means), 28 is a sub-microcomputer (second control device), and 28a is a CPU ( Determination means), ta is the recognition response time, tb is the communication standby time, tc is the output delay time, td is the command delay time, tp1, tq1, tr1 are the first threshold value, tp2, tq2, tr2 are the second threshold values Value.

Claims (5)

Cylinder information and A / D conversion indicating a fuel injection cylinder in order to sequentially A / D convert a fuel pressure detection signal of a fuel pressure sensor that commands fuel injection to each cylinder of the internal combustion engine and detects a fuel pressure that fluctuates with fuel injection A first control device that outputs a fuel pressure detection command comprising a start signal to a port, and inputs the cylinder information and the A / D conversion start signal from the first control device, and inputs the A / D conversion start signal to the port A second controller that sequentially A / D-converts the fuel pressure detection signal of the cylinder recognized based on the cylinder information input to the port from the time point
The second control device transmits a cylinder number recognized based on the cylinder information inputted to the port to the first control device by communication different from signal exchange between the ports,
The first control device includes determination means for determining whether or not the cylinder number received by communication from the second control device matches the number of the fuel injection cylinder .
The determination means measures a recognition response time from when the fuel injection cylinder is switched to when a cylinder number recognized by the second control device is received by communication from the second control device, and the recognition response time is measured. If it is less than or equal to the first threshold value, it is determined that the fuel pressure detection command has been made normally on the condition that the received cylinder number and the fuel injection cylinder number match, and the recognition response time is the first time. When the threshold value is exceeded and below the second threshold value, it is determined that the output delay of the fuel pressure detection command is abnormal on the condition that the received cylinder number and the fuel injection cylinder number match, and the recognition response time When the fuel pressure exceeds the second threshold, it is determined that the fuel pressure detection command output is abnormal. Communication from the second control device to the first control device is regular communication performed at regular intervals,
The second control device measures a communication standby time from when the cylinder information is input to the port until the cylinder number recognized based on the cylinder information is transmitted to the first control device by the periodic communication. A waiting time is transmitted to the first control device together with the recognized cylinder number,
The determination means sets a time obtained by subtracting the received communication waiting time from the measured recognition response time as the recognition response time, and then makes a determination based on a comparison with the first threshold value and the second threshold value. The abnormality determination device for a fuel pressure detection command according to claim 1, wherein the processing is executed. Cylinder information and A / D conversion indicating a fuel injection cylinder in order to sequentially A / D convert a fuel pressure detection signal of a fuel pressure sensor that commands fuel injection to each cylinder of the internal combustion engine and detects a fuel pressure that fluctuates with fuel injection A first control device that outputs a fuel pressure detection command comprising a start signal to a port, and inputs the cylinder information and the A / D conversion start signal from the first control device, and inputs the A / D conversion start signal to the port A second controller that sequentially A / D-converts the fuel pressure detection signal of the cylinder recognized based on the cylinder information input to the port from the time point
The first control device monitors and inputs the signal level of the output port of the cylinder information when the signal level of the output port of the A / D conversion start signal changes a predetermined level, and the cylinder based on the signal level input by the monitor Determining means for determining whether or not the number and the number of the fuel injection cylinder match ;
The determination means measures an output delay time from when the fuel injection cylinder is switched to when the signal level of the output port of the A / D conversion start signal changes to a predetermined value, and the output delay time is the first. When the threshold value is less than or equal to the threshold value, it is determined that the fuel pressure detection command is normally made on the condition that the cylinder number based on the signal level input by the monitor matches the fuel injection cylinder number, and the output delay time is When the first threshold value is exceeded and below the second threshold value, the output of the fuel pressure detection command is delayed on condition that the cylinder number based on the signal level input by the monitor coincides with the fuel injection cylinder number. An abnormality determination device for a fuel pressure detection command, wherein it is determined that there is an abnormality, and an output abnormality of the fuel pressure detection command is determined when the output delay time exceeds the second threshold value. When it is determined that the fuel pressure detection command output is abnormal, the determination means outputs the cylinder information and the A / D conversion start signal again to the port, and subsequently, the signal level of the output port of the cylinder information and the A / D The signal level of the output port of the D conversion start signal is input to the monitor, the signal level input by the monitor coincides with the A / D conversion start signal, and the cylinder number and the fuel injection cylinder number based on the signal level input by the monitor 4. The fuel pressure detection command abnormality determination device according to claim 3, wherein the output pressure abnormality is determined to be an output loss abnormality in which a port output process has been lost, and a port abnormality is determined otherwise. . Cylinder information and A / D conversion indicating a fuel injection cylinder in order to sequentially A / D convert a fuel pressure detection signal of a fuel pressure sensor that commands fuel injection to each cylinder of the internal combustion engine and detects a fuel pressure that fluctuates with fuel injection A first control device that outputs a fuel pressure detection command comprising a start signal to a port, and inputs the cylinder information and the A / D conversion start signal from the first control device, and inputs the A / D conversion start signal to the port A second controller that sequentially A / D-converts the fuel pressure detection signal of the cylinder recognized based on the cylinder information input to the port from the time point
The first control device transmits the number of the fuel injection cylinder to the second control device by communication different from signal exchange between the ports,
The second control device determines whether or not the cylinder number recognized based on the cylinder information input from the port from the first control device matches the fuel injection cylinder number received from the first control device through communication. Determination means to perform,
The determination means measures a command delay time from when the fuel injection cylinder number is received through communication until the cylinder information is input to the port, and when the command delay time is equal to or less than a first threshold value. It is determined that the fuel pressure detection command has been made normally on the condition that the cylinder number recognized based on the cylinder information input to the port matches the received fuel injection cylinder number, and the command delay time is the first delay time. When the threshold value is exceeded and below the second threshold value, the fuel pressure detection command is provided on the condition that the cylinder number recognized based on the cylinder information inputted at the port matches the received fuel injection cylinder number. The fuel pressure detection command abnormality determination is characterized in that when the command delay time exceeds the second threshold value, it is determined that the fuel pressure detection command output is abnormal. Location.

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