JP2015098854A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device capable of avoiding to the possible extent erroneous diagnosis of abnormality of a crank sensor.SOLUTION: An engine control device acquires abnormality flags 1 and 2 showing whether a crank sensor is abnormal or not from two crank sensor diagnosis sections respectively (S460, S462), and when both of the abnormality flags are on and equal (S464:Yes), it is diagnosed that the diagnosis of both of the two crank sensor diagnosis sections is normal and abnormality such as failure occurs in the crank sensor (S466). When both of the abnormality flags are off and equal (S464:No, S470:Yes), it is diagnosed that the diagnosis of both of the two crank sensor diagnosis sections is normal and the crank sensor is normal (S472). When values of the two abnormality flags are different from each other (S460:No, S470:No), it is diagnosed that one of the crank sensor diagnosis sections 30 and 40 is abnormal and the crank sensor 4 is normal (S476).

Description

  The present invention relates to an engine control device that detects an abnormality of a crank sensor.

  Conventionally, it is known to detect an engine operating state based on an engine rotation speed and perform various engine controls based on the detected engine operating state. For example, Patent Document 1 discloses a technique for estimating engine torque based on engine rotation speed.

  The engine rotation speed is usually calculated based on a crank signal that is an output signal of a crank sensor that detects the rotation angle position of the crankshaft. When the crank sensor is abnormal, the engine speed is calculated based on a cam signal that is an output signal of a cam sensor that detects the rotational angle position of the camshaft, instead of the crank signal.

Japanese National Patent Publication No. 11-505588

  The crank sensor is diagnosed as abnormal when the crank sensor itself is abnormal, as well as when the microcomputer performing the abnormality determination process is abnormal. If it is diagnosed that the crank sensor is abnormal, the engine speed is calculated based on the cam signal instead of the crank signal.

  Since the number of cam signal signals is usually smaller than the number of crank signal signals, the accuracy of calculating the engine speed based on the cam signal is lower than that of the crank signal. Therefore, it is desirable to avoid as much as possible to misdiagnose that the crank sensor is normal despite the malfunction of the microcomputer and calculate the engine speed based on the cam signal instead of the crank signal. That is.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an engine control apparatus that avoids misdiagnosis of abnormality of a crank sensor as much as possible.

The engine control apparatus of the present invention includes first speed calculation means, second speed calculation means, first diagnosis means, second diagnosis means, and selection means.
The first speed calculation means calculates the engine rotation speed based on a crank signal output from the crank sensor at every predetermined rotation angle of the crankshaft, and the second speed calculation means calculates the cam sensor at every predetermined rotation angle of the camshaft. The engine speed is calculated based on the cam signal output from the first and second diagnosis means and the second diagnosis means respectively determine whether or not the crank sensor is abnormal based on the crank signal.

  Since the probability that both the first diagnosis means and the second diagnosis means are abnormal is lower than the probability that one diagnosis means is abnormal, both diagnosis means are the same when the diagnosis results of both diagnosis means match. Is considered correct.

  Therefore, the selection means of the engine control device of the present invention selects the engine rotation speed calculated by the first speed calculation means when the diagnosis result of the first diagnosis means and the diagnosis result of the second diagnosis means match normally. When the diagnosis result of the first diagnosis means and the diagnosis result of the second diagnosis means are abnormal and coincide, the engine speed calculated by the second speed calculation means is selected.

  In this way, it is possible to avoid misdiagnosing the crank sensor as abnormal as much as possible by determining whether or not the crank sensor is abnormal using two different diagnostic means and comparing the diagnosis results. Can do.

  Further, when the diagnosis result of the first diagnosis means and the diagnosis result of the second diagnosis means are different, and one is normal and the other is abnormal, it is considered that either the first diagnosis means or the second diagnosis means is abnormal. . The probability that either the first diagnostic means or the second diagnostic means is abnormal and the crank sensor is abnormal is that either the first diagnostic means or the second diagnostic means is abnormal and the crank sensor is normal. Lower than probability.

  Therefore, it is desirable that the selection means selects the engine speed calculated by the first speed calculation means when the diagnosis result of the first diagnosis means is different from the diagnosis result of the second diagnosis means.

The functional block diagram which shows the engine control apparatus by this embodiment. The functional block diagram which shows the crank sensor diagnostic part 1 and 2. FIG. The flowchart which shows the diagnostic process of the crank sensor diagnostic part 1. FIG. The flowchart which shows the number-of-teeth diagnosis process of the crank sensor diagnostic part. The flowchart which shows the missing tooth diagnostic process of the crank sensor diagnostic part 2. FIG. The flowchart which shows the switching process of an engine speed. The time chart which shows the diagnostic process at the time of abnormality. The time chart which shows the other diagnostic processing at the time of abnormality. The time chart which shows the diagnostic process at the time of abnormality by a comparative example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The engine control apparatus 10 shown in FIG. 1 is mainly configured by a microcomputer (hereinafter also referred to as “microcomputer”) including a CPU, a RAM, a ROM, a flash memory, and the like. The engine control apparatus 10 includes engine rotation speed calculation units 20 and 22, crank sensor diagnosis units 30 and 40, a selector 60, a switch 62, a torque monitor 70, a torque controller 80, and the like.

  The engine rotation speed calculation unit 20 calculates the engine rotation speed based on the crank signal detected by the crank sensor 4, and the engine rotation speed calculation unit 22 calculates the engine rotation speed based on the cam signal detected by the cam sensor 6.

  The crank sensor 4 detects the crank teeth 2a that the crank rotor 2 (see FIG. 2) that rotates together with the crankshaft has equiangular intervals along the direction of rotation of the crankshaft. A pulse-like crank signal is output to (see FIG. 7).

  Since the crank rotor 2 is formed with a missing tooth portion 2b lacking the crank teeth 2a at a predetermined rotational angle position, the crank sensor 4 does not output a crank signal in the angular section of the missing tooth portion 2b.

  The cam sensor 6 detects cam teeth that a cam rotor (not shown) that rotates with the camshaft has at a predetermined rotational angle position of the camshaft and outputs a cam signal (see FIG. 7). The cam teeth are wider in the rotational direction than the crank teeth 2a, and the number of teeth of the cam teeth is smaller than the number of teeth of the crank teeth 2a.

  The crank sensor diagnosis units 30 and 40 determine whether or not the crank sensor 4 is abnormal in different processes based on the crank signal output from the crank sensor 4. Details of the crank sensor diagnosis units 30 and 40 will be described later.

The selector 60 selects one of the engine speeds calculated by the engine speed calculators 20 and 22 according to the switching signal of the switch 62.
The switch 62 outputs to the selector 60 a switching signal that instructs which of the engine rotation speeds calculated by the engine rotation speed calculation sections 20 and 22 is selected based on the diagnosis results of the crank sensor diagnosis sections 30 and 40. To do. Details of the switching process of the switch 62 will be described later.

The torque monitor 70 includes a torque estimation unit 72, a required torque calculation unit 74, and a comparator 76.
The torque estimation unit 72 estimates the output torque of the engine from a map or a mathematical formula based on the fluctuation amount of the engine rotation speed. The requested torque calculation unit 74 calculates the torque requested by the driver from a map or a mathematical formula based on the accelerator opening output by the accelerator sensor 8. The comparator 76 compares the estimated torque output from the torque estimation unit 72 with the required torque output from the required torque calculation unit 74. If the estimated torque is greater than the required torque by a predetermined value or more, the injection drive that drives the injector. An injection inhibition signal is output to the device 90.

The torque controller 80 outputs an injection command signal to the injection drive device 90 based on the accelerator opening output by the accelerator sensor 8.
(Crank sensor diagnostic unit 30, 40)
As shown in FIG. 2, the crank sensor diagnostic unit 30 includes a tooth interruption unit 32, a time counter 34, and a diagnostic unit 36. The crank sensor diagnostic unit 40 includes a tooth counter 42, a missing tooth interrupting unit 44, a tooth number diagnostic unit 46, a missing tooth diagnostic unit 48, and an OR circuit 50.

  The tooth interrupt unit 32 and time counter 34 of the crank sensor diagnosis unit 30 and the tooth counter 42, missing tooth interrupt unit 44, and OR circuit 50 of the crank sensor diagnosis unit 40 perform hardware processing by a circuit.

  The diagnosis unit 36 of the crank sensor diagnosis unit 30 and the number of teeth diagnosis unit 46 and the missing tooth diagnosis unit 48 of the crank sensor diagnosis unit 40 perform software processing by executing different control programs stored in a ROM or the like by a common CPU. I do. Different CPUs may be used for the crank sensor diagnosis unit 30 and the crank sensor diagnosis unit 40.

  The tooth interruption unit 32 of the crank sensor diagnosis unit 30 causes the diagnosis unit 36 to generate a hardware interrupt for each crank signal corresponding to the crank tooth 2a. The time counter 34 is a hardware counter that counts for each clock signal or for each divided signal of the clock signal.

  The diagnosis unit 36 executes a diagnosis process for the crank sensor 4 based on a control program stored in a ROM or the like by a hardware interrupt generated for each crank signal by the tooth interruption unit 32. The diagnosis unit 36 sets the abnormality flag 1 to ON when the crank sensor 4 is abnormal, and sets the abnormality flag 1 to OFF when the crank sensor 4 is normal.

  The tooth counter 42 of the crank sensor diagnosis unit 40 is a hardware counter that counts for each crank signal, and counts the number of teeth of the crank teeth 2a. The missing tooth interrupting part 44 detects the missing tooth part 2b of the crank rotor 2 from the crank signal, and causes the tooth number diagnosis part 46 to generate a hardware interrupt.

  The number-of-tooth diagnosis unit 46 performs the number-of-tooth diagnosis processing for each missing tooth portion 2b based on a control program stored in a ROM or the like by a hardware interrupt generated for each missing tooth portion 2b by the missing tooth interrupting portion 44. Execute. The tooth number diagnosis unit 46 diagnoses whether or not the crank sensor 4 is abnormal by determining whether or not the number of teeth of the crank teeth 2a is normally counted based on the crank signal in the tooth number diagnosis process.

  The missing tooth diagnosis unit 48 executes missing tooth diagnosis processing based on a control program stored in a ROM or the like by a timer interrupt generated at a predetermined time interval. The missing tooth diagnosis unit 48 diagnoses whether or not the crank sensor 4 is abnormal by determining whether or not the missing tooth part 2b is normally detected based on the crank signal in the missing tooth diagnosis process.

  The output of the OR circuit 50 is used as the abnormality flag 2. The abnormality flag 2 is turned on when at least one of the tooth number diagnosis unit 46 and the missing tooth diagnosis unit 48 diagnoses that the crank sensor 4 is abnormal, and both the tooth number diagnosis unit 46 and the missing tooth diagnosis unit 48 are turned on. When the crank sensor 4 is diagnosed as normal, it turns off.

(Diagnosis processing)
FIG. 3 shows a diagnosis process executed by the diagnosis unit 36 of the crank sensor diagnosis unit 30. In FIG. 3 and the flowcharts of FIGS. 4 to 6 to be described later, “S” represents a step.

  The diagnosis process of FIG. 3 is executed by a hardware interrupt that occurs for each crank signal corresponding to the crank tooth 2a. The diagnosis unit 36 counts up the crank tooth counter for each crank signal by software processing (S400). The crank tooth counter is cleared in S418 when it is determined in S408 to be interrupted by a crank signal after the missing tooth portion 2b.

  The diagnosis unit 36 acquires the current counter value as the current time from the time counter 34 (S402), and calculates the time interval of the interrupt generated for each crank signal from the following equation (1) (S404).

Interrupt interval = current interrupt time-previous interrupt time (1)
In equation (1), the current interrupt time is the counter value acquired from the time counter 34 in the current diagnostic process, and the previous interrupt time is the counter value acquired from the time counter 34 in the previous diagnostic process.

  This time is an interruption by the crank tooth 2a immediately after the missing tooth portion 2b. When the missing tooth portion 2b exists between the current time and the previous interruption, the interruption interval becomes longer than when the missing tooth portion 2b does not exist. . Therefore, the diagnosis unit 36 calculates the interrupt interval ratio from the following equation (2) (S406), and determines whether or not the interrupt interval ratio is larger than the predetermined value 1 (S408). The predetermined value 1 is set based on the angular interval of the crank teeth 2a when the missing tooth portion 2b is present and the angular interval of the crank teeth 2a when there is no missing tooth portion 2b.

Interrupt interval ratio = current interrupt interval / previous interrupt interval (2)
When the interrupt interval ratio is larger than the predetermined value 1 (S408: Yes), the diagnosis unit 36 determines that the missing tooth portion 2b exists between the current interruption and the previous interruption (S410), and counts up in S400. It is determined whether or not the counter value of the crank tooth counter is a predetermined value 2 (S412). The predetermined value 2 is the total number of teeth of the crank teeth 2 a that the crank rotor 2 has.

  When the number of teeth indicated by the counter value is equal to the predetermined value 2 (S412: Yes), the diagnosis unit 36 uses the interruption by the crank tooth 2a immediately after the current missing tooth part 2b and the crank tooth 2a immediately after the previous missing tooth part 2b. Since the number of teeth of the crank teeth 2a can be normally counted during the interruption, the crank sensor 4 is diagnosed as normal and the abnormality flag 1 is set to OFF (S414), and the process proceeds to S418.

  When the counter value is different from the predetermined value 2 (S412: No), the diagnosis unit 36 correctly counts the crank tooth 2a between the interrupt by the current missing tooth portion 2b and the interrupt by the previous missing tooth portion 2b. It is diagnosed that there is no abnormal number of teeth and the abnormality flag 1 is set to ON (S416).

In S418, the diagnosis unit 36 clears the crank tooth counter (S418), and ends this process.
When the interrupt interval ratio is less than or equal to the predetermined value 1 (S408: No), the diagnosis unit 36 determines that the missing tooth portion 2b does not exist between the current interruption and the previous interruption (S420), and the crank tooth counter It is determined whether or not the counter value is smaller than a predetermined value 2 (S422).

If the missing tooth portion 2b does not exist between the current interruption and the previous interruption, the value of the crank tooth counter counted up in S400 should be smaller than the predetermined value 2.
When the counter value is smaller than the predetermined value 2 (S422: Yes), the diagnosis unit 36 normally counts the number of teeth of the crank teeth 2a between the current interruption and the previous interruption, so that the crank sensor 4 is normal. And the abnormality flag 2 is set to OFF (S424), and this process is terminated.

  When the counter value is equal to or greater than the predetermined value 2 (S422: No), the diagnosis unit 36 diagnoses that the missing tooth portion 2b is not detected or that the number of signals of the crank signal is excessive, and sets the abnormality flag 2. It is set to ON (S426), and this process is terminated.

(Diagnosis processing)
FIG. 4 shows the number of teeth diagnosis process executed by the number of teeth diagnosis unit 46 of the crank sensor diagnosis unit 40. The tooth number diagnosis process of FIG. 4 is executed by a hardware interrupt generated when the missing tooth interrupting unit 44 detects the missing tooth part 2b.

  The tooth number diagnosis unit 46 acquires the counter value of the tooth counter 42 that counts for each crank signal (S430), and calculates the number of teeth of the crank teeth 2a from the following equation (3) (S432). In Equation (3), the previous counter value is the counter value acquired from the tooth counter 42 in the previous tooth number diagnosis process.

Number of teeth = Current counter value-Previous counter value (3)
Since the number-of-teeth diagnosis process in FIG. 4 is executed every time the missing tooth portion 2b is detected, if the crank sensor 4 is normally detecting the crank teeth 2a, the tooth calculated from the equation (3) is used. The number should be equal to the predetermined value 2. The predetermined value 2 is the same value as the predetermined value 2 used in the diagnosis process of FIG.

  Therefore, the number-of-teeth diagnosis unit 46 determines whether or not the number of teeth calculated by Expression (3) is equal to the predetermined value 2 (S434). When the number of teeth is equal to the predetermined value 2 (S434: Yes), the number-of-teeth diagnosis unit 46 diagnoses that the crank sensor 4 is normal, sets the number-of-teeth abnormality flag to OFF (S436), and ends this processing. To do.

  When the number of teeth is different from the predetermined value 2 (S434: No), the number-of-teeth diagnosis unit 46 diagnoses that the crank sensor 4 is abnormal, sets the number-of-teeth abnormality flag to ON (S438), and ends this process. To do.

(Diagnosis processing)
FIG. 5 shows missing tooth diagnosis processing executed by the missing tooth diagnosis unit 48 of the crank sensor diagnosis unit 40. The missing tooth diagnosis process of FIG. 5 is executed by timer interruption at predetermined time intervals.

  The missing tooth diagnosis unit 48 acquires the counter value of the tooth counter 42 that counts for each crank signal (S440), and uses the counter value of the tooth counter 42 acquired in S430 of the tooth number diagnosis process of FIG. A value is acquired from the number-of-teeth diagnosis unit 46 (S442). Then, from Equation (4), the difference between the counter value acquired at S440 and the counter value at the time of tooth number diagnosis acquired from the tooth number diagnosis unit 46 at S442 is calculated as the difference in the number of teeth.

Difference in number of teeth = counter value-counter value during tooth number diagnosis (4)
The counter value at the time of tooth number diagnosis in Expression (4) is the counter value of the tooth counter 42 in the tooth number diagnosis process of FIG. 4 executed by interruption by the missing tooth portion 2b. The value is incremented by 2. The predetermined value 2 is the same value as the predetermined value 2 used in the diagnosis process of FIG.

However, the counter value at the time of tooth number diagnosis acquired from the tooth number diagnosis unit 46 is a constant value and does not increase during the period when the missing tooth part 2b is not detected and the tooth number diagnosis process of FIG. 4 is not executed.
The counter value of the tooth counter 42 acquired in S440 by the timer interruption is a value counted up for each crank signal even when the missing tooth portion 2b is not detected. Therefore, if the crank sensor 4 is normal, the difference in the number of teeth calculated from the equation (4) should be a predetermined value 2 or less.

  Therefore, the missing tooth diagnosis unit 48 determines whether or not the difference in the number of teeth calculated by the equation (4) is equal to or less than a predetermined value 2 (S446). When the difference in the number of teeth is equal to or smaller than the predetermined value 2 (S446: Yes), the missing tooth diagnosis unit 48 diagnoses that the crank sensor 4 is normal and sets the missing tooth abnormality flag to OFF (S448), and this processing Exit.

  When the difference in the number of teeth is larger than the predetermined value (S446: No), the missing tooth diagnosis unit 48 determines that the crank sensor 4 is abnormal, sets the missing tooth abnormality flag to ON (S450), and performs this process. finish.

(Abnormal flag 2 setting process)
The OR circuit 50 determines the abnormality flag 2 if at least one of the tooth number abnormality flag set in the tooth number diagnosis process of FIG. 4 and the missing tooth abnormality flag set in the missing tooth diagnosis process of FIG. An ON signal is output, and if both the tooth number abnormality flag and the missing tooth abnormality flag are OFF, an OFF signal is output as the abnormality flag 2.

(Switching process)
FIG. 6 shows a switching process executed by the switch 62. The switching process executed by the switcher 62 is a hardware process by a circuit.

  The switch 62 acquires the value of the abnormality flag 1 as a diagnosis result from the crank sensor diagnosis unit 30 (S460), and acquires the value of the abnormality flag 2 as a diagnosis result from the crank sensor diagnosis unit 40 (S462).

  In FIG. 7, when both the abnormality flag 1 and the abnormality flag 2 are on and equal as indicated by the dotted line of the abnormality flag 1 and the abnormality flag 2 (S464: Yes), the diagnosis of the crank sensor diagnosis units 30 and 40 is normal. The crank sensor 4 is diagnosed as having an abnormality such as a failure (S466).

  When the crank sensor 4 is abnormal, as shown by the dotted line of the switching signal in FIG. 7, the switch 62 instructs the selector 60 to output the calculation result of the engine speed calculation unit 22 based on the output signal of the cam sensor 6 to the engine. The rotation speed is selected (S468). Since the number of signals of the cam sensor 6 is smaller than the number of signals of the crank sensor 4, the engine speed calculated by the engine speed calculator 22 is less accurate than the engine speed calculated by the engine speed calculator 20.

  Therefore, when the calculation result of the engine rotation speed calculation unit 22 is selected as the engine rotation speed, torque estimation is performed based on the fluctuation amount of the engine rotation speed, compared to the case where the calculation result of the engine rotation speed calculation unit 20 is selected as the engine rotation speed. The fluctuation of the engine torque estimated by the unit 72 increases as shown by the dotted line in FIG. However, when the crank sensor 4 is abnormal, the engine rotation speed must be calculated based on the output signal of the cam sensor 6.

  In FIG. 7, when both the abnormality flag 1 and the abnormality flag 2 are off and equal as indicated by the solid line of the abnormality flag 1 and the solid line of the abnormality flag 2 (S464: No, S470: Yes), the crank sensor diagnosis units 30, 40 The diagnosis is normal, and the crank sensor 4 is diagnosed as normal (S472).

  When the crank sensor 4 is normal, as shown by the solid line of the switching signal in FIG. 7, the switcher 62 instructs the selector 60 to display the calculation result of the engine speed calculation unit 20 based on the output signal of the crank sensor 4. The engine speed is selected (S474).

  Further, in FIG. 8, the values of the abnormality flag 1 and the abnormality flag 2 are different as indicated by the solid line of the abnormality flag 1 and the solid line of the abnormality flag 2, or the dotted line of the abnormality flag 1 and the dotted line of the abnormality flag 2 (S464). : No, S470: No), either one of the crank sensor diagnostic units 30, 40 is abnormal.

  However, the probability that the crank sensor 4 is abnormal and one of the crank sensor diagnosis units 30 and 40 is abnormal is low. Therefore, when the values of the abnormality flag 1 and the abnormality flag 2 are different (S464: No, S470: No), the diagnosis of one of the crank sensor diagnosis units 30 and 40 is abnormal, and the crank sensor 4 is normal. Diagnose (S476).

  For example, the crank sensor diagnosis unit 40 becomes abnormal when the tooth counter 42 of the crank sensor diagnosis unit 40 fails and an abnormality that is not counted up occurs as shown in FIG.

  Then, as indicated by the solid line of the switching signal in FIG. 8, the switching device 62 instructs the selector 60 to select the calculation result of the engine rotation speed calculation unit 20 based on the output signal of the crank sensor 4 as the engine rotation speed. (S478).

  In contrast to the present embodiment, in the comparative example having only one crank sensor diagnosis unit, if the crank sensor diagnosis unit is abnormal even if the crank sensor 4 is normal, the crank sensor 4 is abnormal as shown in FIG. An abnormality flag indicating whether or not is turned on. As a result, the engine speed calculated based on the output signal of the cam sensor 6 is selected.

  When the engine rotation speed is calculated based on the output signal of the cam sensor 6, the estimated torque varies more than the calculation of the engine rotation speed based on the output signal of the crank sensor 4 as described above. When the crank sensor 4 is actually abnormal, the engine rotation speed must be calculated based on the output signal of the cam sensor 6 as described above.

  However, although the crank sensor 4 is normal, it is desirable to avoid calculating the engine speed based on the output signal of the cam sensor 6 instead of the crank sensor 4 due to an abnormality of the crank sensor diagnosis unit.

  In the present embodiment, whether or not the crank sensor 4 is abnormal is diagnosed by both of the crank sensor diagnosis units 30 and 40, and if both diagnosis results are normal or coincide with each other, or if the diagnosis results are different, the crank sensor 4 Is determined to be normal, and if both diagnosis results are abnormal and coincide, the crank sensor 4 is determined to be abnormal.

  In this way, by determining whether or not the crank sensor 4 is abnormal by the two different crank sensor diagnosis units 30 and 40, whether or not the crank sensor 4 is abnormal is diagnosed with high accuracy. It is possible to avoid misdiagnosing that the sensor 4 is abnormal as much as possible.

[Other Embodiments]
In the above embodiment, the crank sensor diagnosis units 30 and 40 have different hardware configurations, and different diagnosis processes are performed. On the other hand, the crank sensor diagnosis units 30 and 40 may have the same hardware configuration, and the same diagnosis process may be performed.

  In the above embodiment, engine control for controlling the injection drive device 90 is performed based on the engine torque estimated from the engine rotation speed. Not only engine torque, but any parameter may be estimated or calculated from the engine rotation speed, and any engine control may be performed based on the parameter.

The engine control device of the present invention is not limited to an engine control device mounted on a vehicle, and may be an engine control device applied to any field.
As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

2: crank rotor, 2a: crank tooth, 2b: missing tooth part, 4: crank sensor, 6: cam sensor, 10: engine control device (first speed calculation means, second speed calculation means, first diagnosis means, second Diagnosis means, selection means), 20: engine rotation speed calculation section (first speed calculation means), 22: engine rotation speed calculation section (second speed calculation means), 30: crank sensor diagnosis section (first diagnosis means), 40: Crank sensor diagnosis unit (second diagnosis means), 60: Selector (selection means), 62: Switch (selection means)

Claims (5)

An engine control device (10) for executing engine control based on engine rotational speed,
First speed calculation means (20) for calculating an engine rotation speed based on a crank signal output from the crank sensor (4) at every predetermined rotation angle of the crankshaft;
Second speed calculating means (22) for calculating an engine speed based on a cam signal output from the cam sensor (6) at every predetermined rotation angle of the camshaft;
First diagnosis means (30, 32, 34, 36, S400 to S426) for determining whether or not the crank sensor is abnormal based on the crank signal;
Second diagnostic means (40, 42, 44, 46, 48, 50, S430 to S438, S440 to S450) for determining whether or not the crank sensor is abnormal based on the crank signal;
When the diagnosis result of the first diagnosis means and the diagnosis result of the second diagnosis means are normal and coincide, the engine speed calculated by the first speed calculation means is selected, and the diagnosis result of the first diagnosis means A selection means (60, 62, S460 to S478) for selecting an engine rotation speed calculated by the second speed calculation means when the diagnosis result of the second diagnosis means coincides abnormally;
An engine control device comprising:   The selection means (S476, S478) selects the engine speed calculated by the first speed calculation means when the diagnosis result of the first diagnosis means is different from the diagnosis result of the second diagnosis means. The engine control device according to claim 1.   The engine control apparatus according to claim 1 or 2, wherein the first diagnosis unit and the second diagnosis unit determine whether or not the crank sensor is abnormal by different processes. The crankshaft has a crank tooth (2a) that rotates together with the crankshaft and is installed at equiangular intervals along the rotation direction of the crankshaft, and a missing tooth portion (2b) from which the crank tooth is missing. A rotor (2) is installed,
The crank sensor detects the crank teeth and outputs the crank signal;
The first diagnosis means counts the time interval between the crank tooth and the crank tooth, and the tooth interruption unit (32) that generates a hardware interrupt by the crank signal corresponding to the crank tooth. A time counter (34), and determining whether or not the crank sensor is abnormal based on the value of the time counter at the time of the hardware interrupt generated by the tooth interrupting unit,
The second diagnostic means detects the missing tooth portion and generates a hardware interrupt to determine the number of teeth of the crank tooth based on the crank signal corresponding to each crank tooth. A tooth counter (42) for counting, and determining whether or not the crank sensor is abnormal based on a value of the tooth counter at the time of the hardware interrupt generated by the missing tooth interrupting unit,
The engine control device according to any one of claims 1 to 3, wherein   The first diagnosing means (S412) and the second diagnosing means (S434) are configured to determine whether the crank teeth counted when the crank rotor rotates once is a predetermined value or not. The engine control device according to claim 4, wherein it is determined whether or not the sensor is abnormal.

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