JP2006077660A - Abnormality diagnostic device for rotation angle sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent erroneous normal/abnormal determination on a rotation angle sensor during big fluctuations in the engine revolution in the process of engine shutdown. <P>SOLUTION: Before the start of the abnormality diagnosis of the rotation angle sensor, it is determined whether conditions for prohibiting the abnormality diagnosis are met or not, and a flag for prohibiting the abnormality diagnosis is turned to the ON/OFF position in response to the determination conclusions. Here, the condition for prohibiting the abnormality diagnosis is that it is before the completion of start, that an idle stop signal is ON, that an ignition switch is OFF, and that the rotation speed of the engine is below the predetermined rotation speed. Then if any one of these conditions applies, the condition for prohibiting the abnormality diagnosis is met, and the flag for prohibiting the abnormality diagnosis is turned to the OFF position, thus the abnormality diagnosis of the rotation angle sensor is prohibited. Because of this, erroneous normal/abnormal determination on the rotation angle sensor during big fluctuations in the engine revolution in the process of engine shutdown can be prevented, and the reliability of the abnormality diagnosis of the rotation angle sensor can be improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an abnormality diagnosis device for a rotation angle sensor that performs abnormality diagnosis of a rotation angle sensor that generates a crank angle signal and a cylinder discrimination signal.

  For example, as disclosed in Japanese Patent Application Laid-Open No. 5-79392, a rotation angle sensor that detects an engine rotation angle (crank angle) generates a crank angle signal pulse at every predetermined crank angle as the engine rotates. In addition, a cylinder discrimination signal pulse is generated at a specific crank angle. In this patent document 1, the cylinder discrimination signal pulse is a pulse added between the crank angle signal pulses. Generally, however, one or several missing teeth are missing from the outer periphery of the signal rotor of the rotation angle sensor. In many cases, a tooth portion is formed and an unequal interval pulse generated at the missing tooth portion is used as a cylinder discrimination signal pulse.

In Patent Document 1, the number of crank angle signal pulses between cylinder discrimination signals (between specific crank angles) is counted, and normality / abnormality of the rotation angle sensor is determined based on whether or not the number of pulses is a normal value. I am doing so.
JP-A-5-79392 (page 3 etc.)

  By the way, the greater the engine speed fluctuation, the more difficult it is to distinguish between the crank angle signal pulse and the cylinder discriminating signal pulse. And the cylinder discrimination signal pulse may be erroneously determined to determine whether the rotation angle sensor is normal or abnormal. As a countermeasure, there is one in which abnormality diagnosis of the rotation angle sensor is prohibited at the time of engine start (during cranking).

  However, the phenomenon that the engine rotation fluctuation increases occurs not only when the engine is started but also when the engine is stopped. Conventionally, the engine control computer is turned off by turning off the ignition switch, and the abnormality diagnosis process of the rotation angle sensor is immediately stopped. Therefore, even if the engine rotation fluctuation is large when the engine is stopped, the rotation angle sensor is normal.・ There was no misjudgment of abnormality, but in recent years, there are some that continue to supply power to the computer even after the ignition switch is turned off to detect the engine stop position, idle stop system, etc. . In such a system, even after the ignition switch is turned off, the computer continues to execute the abnormality diagnosis process of the rotation angle sensor. Therefore, there is a possibility that the normality / abnormality of the rotation angle sensor is erroneously determined by the engine rotation fluctuation when the engine is stopped. is there. In particular, in a vehicle equipped with an idle stop system, the number of engine stops increases when traveling in an urban area, so it is likely that erroneous determination of whether the rotation angle sensor is normal or abnormal due to idle stop is likely to occur.

  The present invention has been made in view of such circumstances. Therefore, the object of the present invention is to provide a rotation angle that can prevent erroneous determination of normality / abnormality of the rotation angle sensor when the engine rotation fluctuation during the engine stop process is large. An object of the present invention is to provide a sensor abnormality diagnosis device.

  To achieve the above object, the invention according to claim 1 is equipped with a rotation angle sensor that generates a crank angle signal for each predetermined crank angle as the engine rotates and generates a cylinder discrimination signal at a specific crank angle. , An abnormality diagnosis means for diagnosing an abnormality of the rotation angle sensor based on a relationship between the crank angle signal and the cylinder discrimination signal during engine rotation, and prohibiting the abnormality diagnosis of the rotation angle sensor when the engine is stopped And a diagnosis prohibiting means. According to the present invention, since abnormality diagnosis of the rotation angle sensor is prohibited when the engine is stopped, it is possible to prevent erroneous determination of normality / abnormality of the rotation angle sensor when the engine rotation fluctuation during the engine stop process is large, The reliability of abnormality diagnosis of the rotation angle sensor can be improved.

  When the present invention is applied to a vehicle equipped with an idle stop system, the abnormality diagnosis of the rotation angle sensor is prohibited when an automatic stop signal for automatically stopping the engine is output by the idle stop system. It is good to do so. In this way, the engine stop due to the idle stop can be detected immediately before the abnormality diagnosis of the rotation angle sensor can be surely prohibited, so that erroneous determination of whether the rotation angle sensor is normal or abnormal due to the idle stop can be reliably prevented.

  Further, as described in claim 3, the abnormality diagnosis of the rotation angle sensor may be prohibited when the engine stop signal is output by turning off the ignition switch. In this way, it is possible to detect the engine stop due to the ignition switch off operation immediately before it is surely prohibited from diagnosing the rotation angle sensor abnormality, so the rotation angle sensor when the engine is stopped due to the ignition switch off operation An erroneous determination of abnormality can be reliably prevented.

  According to a fourth aspect of the present invention, the abnormality diagnosis of the rotation angle sensor may be prohibited when the engine rotation speed falls below a predetermined rotation speed set below the target idle rotation speed. In this way, it is possible to reliably prevent erroneous determination of whether the rotation angle sensor is normal or abnormal even when the engine stops due to a factor other than an ignition switch OFF operation or idle stop.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment embodying the best mode for carrying out the invention will be described with reference to the drawings. First, the configuration of the entire system will be described with reference to FIG.

  The rotation angle sensor 11 is disposed so as to face the outer periphery of the signal rotor 12 that rotates integrally with the crankshaft of the engine, and teeth 13 are formed on the outer periphery of the signal rotor 12 for each predetermined crank angle. Further, a missing tooth portion 14 having one or several teeth 13 missing at a specific crank angle is formed. The rotation angle sensor 11 generates an equidistant pulse (crank angle signal pulse) every time it faces the teeth 13 of the signal rotor 12 as the engine rotates, and the unequal interval pulse (cylinder discrimination signal pulse) at the missing tooth portion 14. Is generated.

  An engine control circuit (hereinafter referred to as “engine ECU”) 15 takes in an output pulse of the rotation angle sensor 11 and discriminates a specific cylinder (specific crank angle) based on unequal interval cylinder discrimination signal pulses. The crank angle is detected by counting the equally spaced crank angle signal pulses with reference to the unequally spaced cylinder discrimination signal pulses, and the engine speed is determined based on the crank angle signal pulse interval (pulse period). To detect. The engine ECU 15 takes in outputs of various sensors (for example, a coolant temperature sensor, an intake pipe pressure sensor, an air flow meter, etc.) other than the rotation angle sensor 11 to detect an engine operation state, and detects the engine operation detected based on the sensor output. The ignition timing of the ignition device 16 is controlled according to the state, and the injection amount of the fuel injection valve 17 is controlled. Further, the engine ECU 15 takes in an ON / OFF / START signal of the ignition switch 18, and starts the engine by energizing a starter (not shown) when the ignition switch 18 is operated from the ON position to the START position.

  An idle stop control circuit (hereinafter referred to as “idle stop ECU”) 21 outputs an idle stop signal (automatic stop signal) to the engine ECU 15 when ignition is performed and fuel injection when a predetermined idle stop condition is satisfied while the vehicle is stopped. To stop the engine automatically. During this idle stop, when the driver performs an operation for starting the vehicle, such as depressing the accelerator pedal, the restart condition is satisfied, and the starter drive signal is output from the idle stop ECU 21 to restart the engine. Let

  Further, the engine ECU 15 executes the rotation angle sensor abnormality diagnosis routine of FIGS. 2 and 3 stored in the built-in ROM, so that the engine ECU 15 is based on the relationship between the crank angle signal pulse and the cylinder discrimination signal pulse during engine rotation. It functions as an abnormality diagnosing means for diagnosing abnormality of the rotation angle sensor 11 and also functions as a diagnosis prohibiting means for prohibiting abnormality diagnosis of the rotation angle sensor 11 when the engine is stopped. The processing contents of the routines in FIGS. 2 and 3 will be described below.

  The rotation angle sensor abnormality diagnosis routine of FIG. 2 is started each time a pulse is input from the rotation angle sensor 11 to the engine ECU 15. When this routine is started, first, in step 101, an abnormality diagnosis prohibition condition determination routine of FIG. 3 described later is executed to determine whether or not the abnormality diagnosis prohibition condition is satisfied, and according to the determination result. Turn on / off the abnormality diagnosis prohibition flag.

  Thereafter, the process proceeds to step 102, where it is determined whether or not the abnormality diagnosis prohibition flag is set to ON, which means that abnormality diagnosis is prohibited. If the abnormality diagnosis prohibition flag is set to ON, the abnormality diagnosis after step 103 is performed. This routine is terminated without executing the processing.

On the other hand, if it is determined in step 102 that the abnormality diagnosis prohibition flag is OFF (abnormality diagnosis permitted), abnormality diagnosis processing after step 103 is executed as follows. First, in step 103, a pulse period T (i) that is an elapsed time from the previous pulse input timing to the current pulse input timing is calculated. Thereafter, the routine proceeds to step 104, where the pulse period parameter Tx for comparing the length of the current pulse period T (i) with the previous pulse period T (i-1) and the previous pulse period T (i-2). Is calculated by the following equation.
Tx = T (i-2) × T (i) / T (i-1) ²

  Thereafter, the process proceeds to step 105, where the pulse period parameter Tx is compared with a determination value for determining the unequal interval cylinder discrimination signal pulse (missing tooth portion 14). It is determined that the current pulse is an equally spaced crank angle signal pulse, the process proceeds to step 106, the crank counter C is incremented, and this routine is terminated.

  Thereafter, when it is determined in step 105 that the pulse period parameter Tx is larger than the determination value, it is determined that the current pulse is a non-uniformly spaced cylinder determination signal pulse (missing tooth portion 14), and the step Proceeding to 107, the count value of the crank counter C is normal corresponding to the total number of teeth 13 (total number of equally spaced crank angle signal pulses) existing between unequal interval cylinder discrimination signal pulses (missing tooth portion 14). If it is a normal value, the process proceeds to step 108, the rotation angle sensor 11 is determined to be normal, the process proceeds to step 109, the crank counter C is reset to the initial value, This routine ends. As a result, the crank counter C is reset to the initial value every time a non-uniformly spaced cylinder discrimination signal pulse is input, and then the equally spaced crank angle signal until the non-uniformly spaced cylinder determination signal pulse is input. The operation of counting the number of pulses is repeated.

  On the other hand, if it is determined in step 107 that the count value of the crank counter C is not a normal value, the process proceeds to step 110, the rotation angle sensor 11 is determined to be abnormal, and the process proceeds to step 111. The fail-safe process is executed, the abnormality information is stored in a rewritable nonvolatile memory such as a backup RAM of the engine ECU 15, a warning is displayed, and this routine is terminated.

  On the other hand, when the abnormality diagnosis prohibition condition determination routine of FIG. 3 is started in step 101, first, in step 201, whether or not the start is completed is determined by whether or not the engine speed has exceeded the start completion determination value after cranking is started. If the start is not yet completed, the abnormality diagnosis prohibition condition is satisfied, and the routine proceeds to step 206 where the abnormality diagnosis prohibition flag is set to ON.

  If it is determined in step 201 that the start is completed, the process proceeds to step 202, where it is determined whether the idle stop signal is output (ON) from the idle stop ECU 21, and the idle stop signal is output (ON). If so, the abnormality diagnosis prohibition condition is satisfied, and the routine proceeds to step 206, where the abnormality diagnosis prohibition flag is set to ON.

  If it is determined in step 202 that the idle stop signal is not output (ON), the process proceeds to step 203, where it is determined whether the ignition switch 18 has been turned OFF, and the ignition switch 18 has been turned OFF. If so, the abnormality diagnosis prohibition condition is satisfied, and the routine proceeds to step 206, where the abnormality diagnosis prohibition flag is set to ON.

  If it is determined in step 203 that the ignition switch 18 has not been turned OFF, the process proceeds to step 204, in which it is determined whether or not the engine rotational speed has decreased below a predetermined rotational speed set below the target idle rotational speed. If it is determined that the engine rotational speed has decreased below the predetermined rotational speed, the abnormality diagnosis prohibition condition is satisfied, the process proceeds to step 206, and the abnormality diagnosis prohibition flag is set to ON.

  If it is determined in step 204 that the engine rotational speed has not decreased below the predetermined rotational speed, the routine proceeds to step 205, where the abnormality diagnosis prohibition flag is set to OFF and abnormality diagnosis processing is permitted.

  The control example of the present embodiment described above will be described with reference to the time chart of FIG. In the example of FIG. 4, when the idle stop execution condition is satisfied and the idle stop signal is turned ON at time t1, the abnormality diagnosis prohibition condition is immediately satisfied, the abnormality diagnosis prohibition flag is set to ON, and the rotation angle sensor 11 abnormality diagnosis is prohibited. Thereafter, at time t2, when the driver performs an operation for starting the vehicle, such as depressing the accelerator pedal, and the restart condition is satisfied, the idle stop signal is turned off and engine cranking is started. As a result, before the time t3 until the engine rotation speed exceeds the start completion determination value and it is determined that the start is complete, the abnormality diagnosis prohibition condition continues to be satisfied, and the abnormality diagnosis prohibition flag is maintained ON, and the rotation angle sensor The state where 11 abnormality diagnosis is prohibited is maintained. Thereafter, at the time t3 when it is determined that the start is completed, the abnormality diagnosis prohibition flag is turned OFF, and abnormality diagnosis of the rotation angle sensor 11 is permitted.

  According to the present embodiment described above, the abnormality diagnosis of the rotation angle sensor 11 is prohibited when the engine is stopped. Therefore, the normality / abnormality of the rotation angle sensor 11 when the engine rotation fluctuation is large during the engine stop process. Can be prevented, and the reliability of abnormality diagnosis of the rotation angle sensor 11 can be improved.

  In addition, in the present embodiment, the abnormality diagnosis of the rotation angle sensor 11 is prohibited when the idle stop signal is turned on, so that the engine stop due to the idle stop is detected immediately before that and the abnormality diagnosis of the rotation angle sensor 11 is performed. It can be surely prohibited, and erroneous determination of whether the rotation angle sensor 11 is normal or abnormal due to idle stop can be reliably prevented.

  Further, in this embodiment, the abnormality diagnosis of the rotation angle sensor 11 is prohibited when the engine stop signal is output by the OFF operation of the ignition switch 18, so that the engine stop by the OFF operation of the ignition switch 18 is immediately before that. Accordingly, the abnormality diagnosis of the rotation angle sensor 11 can be reliably prohibited, and erroneous determination of whether the rotation angle sensor 11 is normal or abnormal when the engine is stopped due to the OFF operation of the ignition switch 18 can be reliably prevented.

  In addition, in this embodiment, since the abnormality diagnosis of the rotation angle sensor 11 is prohibited when the engine rotation speed falls below a predetermined rotation speed set below the target idle rotation speed, the ignition switch 18 is turned off. Even when the engine stalls when the engine rotation is stopped due to a factor other than the operation or idle stop, it is possible to reliably prevent erroneous determination of whether the rotation angle sensor 11 is normal or abnormal.

  The present invention can also be applied to a vehicle not equipped with an idle stop system, and any of the steps 201 to 204 can be omitted or another condition can be added as an abnormality diagnosis prohibition condition. You may do it.

It is a block diagram which shows schematic structure of the whole system in one Example of this invention. It is a flowchart which shows the flow of a process of a rotation angle sensor abnormality diagnosis routine. It is a flowchart which shows the flow of a process of abnormality diagnosis prohibition condition determination routine. It is a time chart explaining the example of control of an Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Rotation angle sensor, 12 ... Signal rotor, 13 ... Teeth, 14 ... Missing tooth part, 15 ... Engine ECU (abnormality diagnosis means, diagnosis prohibition means), 18 ... Ignition switch, 21 ... Idle stop ECU

Claims (4)

In what is equipped with a rotation angle sensor that generates a crank angle signal for each predetermined crank angle as the engine rotates and generates a cylinder discrimination signal at a specific crank angle,
Abnormality diagnosis means for performing abnormality diagnosis of the rotation angle sensor based on the relationship between the crank angle signal and the cylinder discrimination signal during engine rotation;
An abnormality diagnosis device for a rotation angle sensor, comprising: diagnosis prohibiting means for prohibiting abnormality diagnosis of the rotation angle sensor when the engine is stopped. Applied to vehicles equipped with an idle stop system that automatically stops and restarts the engine,
2. The rotation angle sensor according to claim 1, wherein the diagnosis prohibiting unit prohibits abnormality diagnosis of the rotation angle sensor when an automatic stop signal for automatically stopping the engine is output by the idle stop system. Abnormality diagnosis device.   The abnormality diagnosis of the rotation angle sensor according to claim 1 or 2, wherein the diagnosis prohibiting means prohibits the abnormality diagnosis of the rotation angle sensor when an engine stop signal is output by turning off an ignition switch. apparatus.   4. The diagnosis prohibiting means prohibits abnormality diagnosis of the rotation angle sensor when the engine rotation speed falls below a predetermined rotation speed set below a target idle rotation speed. The abnormality diagnosis device for a rotation angle sensor according to any one of the above.

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