JP4341425B2 - Abnormality judgment device for rotational speed sensor - Google Patents

Description

  The present invention relates to an abnormality determination device for a rotational speed sensor, and more particularly to an abnormality determination device for a rotational speed sensor that determines an abnormality based on an output voltage of the rotational speed sensor.

  Conventionally, the rotational speed of the engine (crankshaft) is used as a parameter for controlling the engine. In order to detect the rotational speed, the vehicle is provided with a rotational speed sensor. If the rotational speed sensor is abnormal and the rotational speed is not accurately detected, the engine is not controlled correctly, and it is necessary to determine the abnormality of the rotational speed sensor.

  In paragraphs 0055 to 0069 and FIGS. 9 to 13 of Japanese Patent Application Laid-Open No. 2003-113734 (Patent Document 1), an abnormality determination device that determines abnormality of a crank angle sensor (rotational speed sensor) is disclosed. The abnormality determination device described in Patent Literature 1 includes a crank angle sensor and a control unit to which an output voltage of the crank angle sensor is input. The control unit records the output voltage of the crank angle sensor for each engine speed, and if the output voltage is below the abnormality determination voltage, and if there is an output voltage, it diagnoses a mounting failure and there is no output voltage at all. Is determined to be disconnected. The abnormality determination voltage is set to increase in proportion to the engine speed while maintaining a predetermined difference from the design value of the output voltage of the crank angle sensor.

According to the abnormality determination device described in this publication, when the output voltage of the crank angle sensor is lower than the abnormality determination voltage and there is a crank signal voltage output, it is determined that the mounting is defective, and the output voltage is completely If not, it is determined as a disconnection. As a result, when there is an abnormality due to an improper mounting of the crank angle sensor, it can be determined by distinguishing the improper mounting from the malfunction of the crank angle sensor itself, a short circuit of the wiring, an abnormality due to damage of the crank angle sensor components, or the like. .
JP 2003-113734 A

  However, in the abnormality determination device described in the above-mentioned publication, the difference between the abnormality determination voltage and the design value of the output voltage is constant regardless of the engine speed. Therefore, even in a region where the engine speed is high, even if the speed sensor is normal, it may be determined as abnormal as follows. That is, the output voltage of the rotational speed sensor increases in proportion to the rotational speed of the engine. Therefore, in the region where the engine speed is high, the output voltage is high, so that the error during detection becomes large. Therefore, even if the rotation speed sensor is normal, the detected output voltage may be lower than the abnormality determination voltage. In this case, in the abnormality determination device described in the above-mentioned publication, if the output voltage falls below the abnormality determination voltage, the rotation speed sensor is determined to be abnormal, so that the rotation speed sensor is erroneously determined to be abnormal. There was a risk of it.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to determine whether the rotational speed sensor is normal or abnormal with high accuracy. Is to provide.

  An abnormality determination device for a rotational speed sensor according to a first aspect of the present invention determines an abnormality of a rotational speed sensor that detects the rotational speed of an engine. The abnormality determination device includes an acquisition unit for acquiring the output voltage of the rotation speed sensor, and whether or not the output voltage acquired by the acquisition unit is included in an allowable range that increases as the engine rotation speed increases. And determining means for determining whether the rotational speed sensor is normal or abnormal.

  According to the first invention, the acquisition means acquires the output voltage of the rotation speed sensor. For example, when the engine speed is high and the output voltage is high, an output voltage having a large error from the actual output voltage can be acquired. The determination means determines whether the rotational speed sensor is normal or abnormal based on whether or not the acquired output voltage is included in an allowable range that increases as the rotational speed of the engine increases. Thereby, for example, if it is determined that the rotational speed sensor is normal when the output voltage is within the allowable range, even if an output voltage having a large error from the actual output voltage is obtained. The acquired output voltage is included in the allowable range, and it can be determined that the rotation speed sensor is normal. As a result, it is possible to suppress an erroneous determination that the rotational speed sensor is abnormal, and to provide an abnormality determination device for the rotational speed sensor that can accurately determine whether the rotational speed sensor is normal or abnormal. be able to.

  In the abnormality determination device for the rotational speed sensor according to the second invention, in addition to the configuration of the first invention, the determining means is configured so that when the output voltage acquired by the acquiring means is within an allowable range, the rotational speed sensor is A means for determining that the rotation speed sensor is abnormal when the output voltage acquired by the acquisition means is not included in the allowable range is included.

  According to the second invention, the determination means determines that the rotation speed sensor is normal when the output voltage acquired by the acquisition means is included in the allowable range, and determines that the rotation speed sensor is not included in the allowable range. Is determined to be abnormal. As a result, when the rotation speed sensor is normal and the output voltage having a large error from the actual output voltage is acquired, the acquired output voltage is included in the allowable range, and the rotation speed sensor Can be determined to be normal. As a result, it is possible to suppress erroneous determination that the rotation speed sensor is abnormal, and to accurately determine whether the rotation speed sensor is normal or abnormal.

  In the abnormality determination device for the rotational speed sensor according to the third invention, in addition to the configuration of the first or second invention, the abnormality determination device for the rotational speed sensor outputs the output of the rotational speed sensor in correspondence with the rotational speed of the engine. Storage means for storing the voltage in advance, and means for calculating an allowable range based on the engine speed and the output voltage stored in the storage means are further included.

  According to the third invention, the storage means stores in advance the output voltage of the rotation speed sensor in correspondence with the engine speed, and the calculation means calculates the engine speed and the output voltage stored in the storage means. Based on this, an allowable range is calculated. Thereby, the allowable range corresponding to the engine speed can be calculated.

  An abnormality determination device for a rotational speed sensor according to a fourth aspect of the invention determines an abnormality of a rotational speed sensor that detects the rotational speed of the engine. The rotation speed sensor is a sensor that alternately outputs a positive voltage value and a negative voltage value when the rotation speed sensor is normal. The abnormality determination device includes an acquisition unit for acquiring the output voltage of the rotation speed sensor, a calculation unit for calculating an average voltage of the output voltage of the rotation speed sensor in a predetermined period, an average voltage, Means for comparing with a predetermined voltage, and determination means for determining whether the rotational speed sensor is normal or abnormal based on a result of comparing the average voltage with the predetermined voltage; including.

  According to the fourth invention, the acquisition means acquires the output voltage of the rotation speed sensor, and the calculation means calculates an average voltage of the output voltage of the rotation speed sensor during a predetermined period. If the rotation speed sensor is normal, the rotation speed sensor alternately outputs a positive voltage value and a negative voltage value. The voltage becomes a predetermined voltage (for example, 0 volts). If there is an abnormality in the rotational speed sensor, for example, the period when the output voltage is positive becomes longer than the period when it becomes negative, or the period when the output voltage is negative becomes longer than the period when it becomes positive The average voltage is a voltage different from the predetermined voltage. The calculated average voltage is compared with a predetermined voltage, and the determination means determines whether the rotational speed sensor is normal or abnormal based on the result of comparing the average voltage with the predetermined voltage. Determine. As a result, the rotation speed sensor is normal, but the engine rotation speed is high and the output voltage is high. If it is a predetermined voltage, it can be determined that the rotational speed sensor is normal. As a result, it is possible to suppress an erroneous determination that the rotational speed sensor is abnormal, and to provide an abnormality determination device for the rotational speed sensor that can accurately determine whether the rotational speed sensor is normal or abnormal. be able to.

  In the abnormality determination device for the rotation speed sensor according to the fifth invention, in addition to the configuration of the fourth invention, the determination means determines that the rotation speed sensor is abnormal when the average voltage is different from a predetermined voltage. Means for determining.

According to the fifth invention, when the average voltage is different from the predetermined voltage, it is determined that the rotational speed sensor is abnormal. Thus, although the rotation speed sensor is normal, the average voltage is determined in advance even when an output voltage having a large error from the actual output voltage is acquired because the engine rotation speed is high and the output voltage is high. If the voltage is the determined voltage, it can be determined that the rotational speed sensor is normal. As a result, it is possible to suppress erroneous determination that the rotational speed sensor is abnormal, and to accurately determine whether the rotational speed sensor is normal or abnormal. In the abnormality determination device, in addition to the configuration of any one of the first to fifth inventions, the output voltage of the rotation speed sensor decreases as the engine rotation speed decreases. The abnormality determination device prohibits the determination by the determination unit when the engine rotation speed is lower than the predetermined rotation speed and the means for comparing the rotation speed of the engine with the predetermined rotation speed. Means for further comprising.

  According to the sixth aspect, the engine speed is compared with a predetermined engine speed, and when the engine speed is lower than the predetermined engine speed, the determination by the determining means is prohibited. As a result, the rotation speed sensor is normal, but the abnormality determination is performed when the output voltage is lower than the voltage necessary for performing the abnormality determination because the engine rotation speed is lower than the predetermined rotation speed. Can be banned. As a result, it can be accurately determined whether the rotational speed sensor is normal or abnormal.

  In the abnormality determination device for the rotational speed sensor according to the seventh aspect of the invention, in addition to the configuration of any one of the first to fifth aspects, the output voltage of the rotational speed sensor changes according to the rotational speed of the engine. The abnormality determination device has means for determining whether or not fluctuations in engine speed within a predetermined period are within a predetermined range, and fluctuations in engine speed are predetermined. And a means for prohibiting determination by the determination means.

  According to the seventh aspect of the present invention, it is determined whether or not the fluctuation of the engine speed within a predetermined period is within a predetermined range, and the fluctuation of the engine speed is within a predetermined range. If it is outside, determination by the determination means is prohibited. As a result, the abnormality determination can be prohibited when the engine speed is not stable and the output voltage is transiently increased or decreased and is unstable. As a result, it can be accurately determined whether the rotational speed sensor is normal or abnormal.

  In the abnormality determination device for the rotational speed sensor according to the eighth aspect of the invention, in addition to the configuration of any one of the first to fifth aspects, the output voltage of the rotational speed sensor changes according to the rotational speed of the engine. The abnormality determination device includes a means for measuring a period after the engine is started, a means for determining whether a period after the engine is started has passed a predetermined period, and And a means for prohibiting the determination by the determination means when the period from the start of the engine has not passed the predetermined period.

  According to the eighth aspect, the period after the engine is started is measured, and it is determined whether or not the predetermined period has elapsed since the engine was started. When the period from the start of the engine has not passed a predetermined period, the determination by the determination unit is prohibited. As a result, a predetermined period has not elapsed since the engine was started. For example, because the engine has not been warmed up, the engine speed is not stable, and the output voltage becomes transient. The abnormality determination can be prohibited when there is a risk of becoming larger or smaller. As a result, it can be accurately determined whether the rotational speed sensor is normal or abnormal.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
With reference to FIG. 1, a vehicle equipped with an abnormality detection device for a rotational speed sensor according to a first embodiment of the present invention will be described. As shown in FIG. 1, the vehicle includes an engine 100 and an ECU (Electronic Control Unit) 200. The abnormality detection device for the rotational speed sensor according to the present embodiment is realized by a program executed by ECU 200, for example.

  Engine 100 includes an intake pipe 102, an intake manifold 104, an exhaust manifold 106, an exhaust pipe 108, and a catalyst 110. Intake pipe 102 includes an air cleaner 112 and a throttle valve 114 provided in the vicinity of the intake port.

  Air sucked into the engine 100 (hereinafter referred to as “intake”) is sucked from the intake intake of the intake pipe 102 and filtered by the air cleaner 112. The intake air amount is adjusted by the throttle valve 114.

  The intake air sucked into the intake pipe 102 passes through the intake manifold 104 and is introduced into the combustion chamber of each cylinder of the engine 100 as an air-fuel mixture together with fuel injected by an injector (not shown). In the combustion chamber of each cylinder of engine 100, the air-fuel mixture is ignited by a spark plug (not shown) and burned. The combusted air-fuel mixture, that is, exhaust gas, enters the exhaust pipe 108 through the exhaust manifold 106, is purified by the catalyst 110, and is then discharged outside the vehicle.

  Engine 100 depresses a piston (not shown) slidably provided in each cylinder by the combustion of the air-fuel mixture, and rotates a crankshaft (not shown).

  A radiator 116 is connected to the engine 100 in order to cool the engine 100 that has generated heat due to the combustion of the air-fuel mixture. Radiator 116 exchanges heat between the cooling water flowing through engine 100 and the air. The engine 100 is cooled by cooling the cooling water by heat exchange.

  A timing rotor 118 is provided on the crankshaft of the engine 100. A plurality of convex portions are provided on the outer peripheral portion of the timing rotor 118 at predetermined intervals. As the timing rotor 118 rotates together with the crankshaft, the rotation speed of the crankshaft, that is, the engine rotation speed is detected.

  The ECU 200 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) 202, and a counter 204. The ROM 202 stores a program executed by the CPU of the ECU 200. The counter 204 measures a time such as an elapsed time after the engine 100 is started and a time when an output voltage of a rotation speed sensor described later is acquired. The ECU 200 is connected to an air flow meter 210, an ignition switch 220, a water temperature sensor 230, a rotation speed sensor 240, and a warning lamp 250.

  The air flow meter 210 is a hot wire type air flow meter. The air flow meter 210 is provided in the vicinity of the intake port of the intake pipe 102. Air flow meter 210 includes a heating wire 212 and an intake air temperature sensor 214. The heating wire 212 generates heat when energized. The heating wire 212 is cooled by intake air. The intake air amount is calculated based on the degree to which the heating wire 212 is cooled. The intake air temperature sensor 214 is provided integrally with the air flow meter 210. The intake air temperature sensor 214 detects the intake air temperature.

  The ignition switch 220 is operated by the driver. When the engine 100 is started, the ignition switch 220 is turned on. When the engine 100 is stopped, the ignition switch 220 is turned off. In addition, a start switch or the like may be used in place of the ignition switch 220.

  The water temperature sensor 230 is provided in the radiator 116. Water temperature sensor 230 detects the temperature of cooling water of engine 100. The rotation speed sensor 240 is provided so as to face the convex portion provided on the outer peripheral portion of the timing rotor 118. In the rotation speed sensor 240, electric power is generated by the rotation of the timing rotor 118. The voltage of the electric power generated by the rotation speed sensor 240 is acquired by the ECU 200, and a pulse signal is generated (converted into a pulse signal) based on the acquired voltage.

  The warning lamp 250 is provided on a combination meter (not shown) provided on the instrument panel (not shown). The warning lamp 250 is turned on when there is an abnormality in the devices.

  The CPU of the ECU 200 controls each device so as to execute a program stored in the ROM 202 based on the signal transmitted from each sensor and the time measured by the counter 204 and perform a desired operation.

  The rotation speed sensor 240 will be further described with reference to FIG. Rotational speed sensor 240 includes a pickup coil 242, a conducting wire 244, and a shield wire 246. The pickup coil 242 is provided close to the timing rotor 118. As the timing rotor 118 rotates, electric power is generated in the pickup coil 242. When the convex portion of the timing rotor 118 approaches the pickup coil 242, the voltage of the generated electric power increases. When the convex portion of the timing rotor 118 moves away from the pickup coil 242, the generated electric power voltage decreases. Therefore, the voltage of the electric power generated by the rotation speed sensor 240 becomes a wave shape, and the rotation speed sensor 240 alternately outputs a positive voltage value and a negative voltage value. The pickup coil 242 is connected to the ECU 200 by a conductive wire 244.

  The shield wire 246 is provided so as to surround the conductive wire 244. The shield wire 246 is grounded to the conductive wire 244. Thereby, the shield wire 246 suppresses the influence which the electromagnetic waves etc. from the outside of the rotation speed sensor 240 have on the conducting wire 244, and suppresses the generation of noise.

  Since the shield wire 246 is provided so as to surround the conductive wire 244, charges are accumulated in the shield wire 246 and the conductive wire 244, which may act like a capacitor. In this case, for example, even if the conducting wire 244 is cut, the voltage of the rotational speed sensor 240 is acquired. Therefore, the pulse signal obtained by converting the output voltage of the rotation speed sensor 240 can be acquired even when the conducting wire 244 is disconnected. Since the pulse signal is a rectangular wave and represents only the timing, there is a risk of erroneous determination if the abnormality of the rotation speed sensor 240 is determined based on whether or not the pulse signal is acquired. Therefore, in the present embodiment, it is determined whether rotation speed sensor 240 is normal or abnormal using the magnitude (output voltage value) of the output voltage of rotation speed sensor 240.

  A map stored in the ROM 202 will be described with reference to FIG. The ROM 202 stores a map showing the relationship between the engine speed NE and the output voltage V (design value) of the engine speed sensor 240 at the normal time. As shown in FIG. 3, the output voltage of the rotation speed sensor 240 at normal time increases in proportion to the rotation speed of the timing rotor 118, that is, the rotation speed NE of the engine 100. Similarly, actual output voltage V increases as engine speed increases. Therefore, the higher the number of revolutions of engine 100, the greater the error between the actual output voltage and the acquired output voltage.

With reference to FIG. 4, a control structure of a program executed by ECU 200 in the abnormality determination device for the rotational speed sensor according to the present embodiment will be described.

  In step (hereinafter step is abbreviated as S) 100, ECU 200 determines whether engine 100 has been started or not. Whether or not engine 100 has been started may be determined based on, for example, whether or not ignition switch 220 is turned on. If engine 100 has started (YES in S100), the process proceeds to S102. If not (NO in S100), the process proceeds to S100.

  In S102, ECU 200 starts counting a timer in order to measure an elapsed time since engine 100 is started. In S104, ECU 200 detects engine speed NE (1) based on the pulse signal.

  In S106, ECU 200 determines whether or not engine speed NE (1) is larger than a predetermined engine speed NE (0). If engine speed NE (1) is larger than predetermined engine speed NE (0) (YES in S106), the process proceeds to S108. If not (NO in S106), the process proceeds to S100, and the processes after S108 are prohibited. This rotational speed NE (0) prohibits the processing after 108 when the rotational speed NE of the engine 100 is low and the output voltage of the rotational speed sensor 240 is smaller than the voltage necessary for performing abnormality determination. It is set to prohibit abnormality determination of the rotation speed sensor 240.

  In S108, ECU 200 detects engine speed NE (2). In S110, ECU 200 determines whether or not the difference between engine speed NE (1) and engine speed NE (2) is smaller than a predetermined engine speed difference ΔNE (0). If the difference between rotation speed NE (1) and rotation speed NE (2) is smaller than a predetermined rotation speed difference ΔNE (0) (YES in S110), the process proceeds to S112. If not (NO in S110), the process proceeds to S100, and the processes after S112 are prohibited. This ΔNE (0) prohibits the processing from S112 onward when the rotational speed NE of the engine 100 is not stable and the output voltage of the rotational speed sensor 240 increases or decreases transiently. It is set to prohibit the abnormality determination of the number sensor 240.

  In S112, ECU 200 determines whether or not an elapsed time T from the start of engine 100 has passed a predetermined time T (0). If elapsed time T from the start of engine 100 has passed a predetermined time T (0) (YES in S112), the process proceeds to S114. If not (NO in S112), the process proceeds to S100, and the processes after S114 are prohibited. This T (0) is the case where the engine 100 has not been stabilized, for example, when the engine 100 has not been warmed up, and the output voltage of the engine speed sensor 240 may not be stable. , The processing after S114 is prohibited, and abnormality determination of the rotational speed sensor 240 is prohibited.

  In S114, ECU 200 detects engine speed NE (3). In S116, ECU 200 calculates a determination criterion based on the map stored in ROM 202 and detected rotational speed NE (3). The determination criteria means a lower limit value V (L) and an upper limit value V (H) of the allowable range of the output voltage V. Instead of calculating the determination criteria, it may be read from a map stored in advance.

  In S118, ECU 200 acquires output voltage V of rotation speed sensor 240. In S120, ECU 200 determines whether or not output voltage V is included in the allowable range. Specifically, it is determined whether or not the output voltage V is larger than the lower limit value V (L) and smaller than the upper limit value V (H). If output voltage V is greater than lower limit value V (L) and smaller than upper limit value V (H) (YES in S120), the process proceeds to S122. If not (NO in S120), the process proceeds to S124.

  In S122, ECU 200 determines that rotation speed sensor 240 is normal. In S124, ECU 200 determines that rotation speed sensor 240 is abnormal. In S126, ECU 200 turns on warning lamp 250 and stores a code indicating that rotation speed sensor 240 is abnormal.

  The operation of ECU 200 in the abnormality determination device for the rotational speed sensor according to the present embodiment based on the above-described structure and flowchart will be described.

  When ignition switch 220 is turned on by the driver and engine 100 is started (YES in S100), measurement of elapsed time after engine 100 is started is started (S102), and engine speed NE (1 ) Is detected (S104).

  If engine speed NE (1) is larger than predetermined engine speed NE (0) (YES in S106), engine speed NE (2) is detected (S108).

  When engine speed NE (1) is smaller than predetermined engine speed NE (0) (NO in S106), the processes of S100 and S104 are repeated. As a result, the processing after S108 is prohibited, and the rotational speed NE of the engine 100 is low. Therefore, when the output voltage of the rotational speed sensor 240 is smaller than the voltage necessary for performing abnormality determination, the rotational speed sensor 240 Abnormality judgment can be prohibited. Here, it is assumed that engine speed NE (1) of engine 100 is larger than predetermined engine speed NE (0) (YES in S106).

  When the rotational speed NE (2) of the engine 100 is detected (S108), the difference between the rotational speed NE (1) and the rotational speed NE (2) of the engine 100 is a predetermined rotational speed difference ΔNE (0). It is determined whether or not the value is smaller than (S110).

  If the difference between the rotational speed NE (1) and the rotational speed NE (2) is smaller than a predetermined rotational speed difference ΔNE (0) (YES in S110), the elapsed time from the start of the engine 100 It is determined whether or not T has passed a predetermined time T (0) (S112).

  If the difference between rotation speed NE (1) and rotation speed NE (2) is greater than a predetermined rotation speed difference ΔNE (0) (NO in S110), the processes of S100 to S108 are repeated. As a result, the processing after S112 is prohibited, and when the rotational speed NE of the engine 100 is not stable and the output voltage of the rotational speed sensor 240 increases or decreases transiently, the rotational speed sensor 240 Abnormality judgment can be prohibited. Here, it is assumed that the difference between rotational speed NE (1) and rotational speed NE (2) is smaller than a predetermined rotational speed difference ΔNE (0) (YES in S110).

  When elapsed time T from the start of engine 100 has passed a predetermined time T (0) (YES in S112), engine speed NE (3) is detected (S114).

  If elapsed time T since engine 100 has not started exceeds predetermined time T (0) (NO in S112), the processes of S100 to S112 are repeated. Thereby, the processing after S114 is prohibited. For example, when the engine 100 has not been warmed up, the rotational speed of the engine 100 is not stable, and the output voltage of the rotational speed sensor 240 is not stable. In a case where there is a fear, abnormality determination of the rotation speed sensor 240 can be prohibited. Here, it is assumed that elapsed time T from the start of engine 100 has passed a predetermined time T (0) (YES in S112).

  When engine speed NE (3) of engine 100 is detected (S114), lower limit value V (L of the allowable range of output voltage V is determined based on the map stored in ROM 202 and detected engine speed NE (3). ) And an upper limit value V (H) are calculated (S116). As shown in FIG. 5A, the lower limit value V (L) and the upper limit value V (H) increase as the rotational speed NE of the engine 100 increases, and the deviation width from the normal output voltage. Is calculated to be large. As a result, as indicated by the shaded portion in FIG. 5A, the allowable range of output voltage V of rotation speed sensor 240 increases as the rotation speed NE of engine 100 increases.

  When the lower limit value V (L) and the upper limit value V (H) of the allowable range of the output voltage V are calculated (S116), the output voltage V of the rotation speed sensor 240 is acquired (S118). If rotation speed sensor 240 is normal, output voltage V is larger than lower limit value V (L) and smaller than upper limit value V (H) (YES in S120), and is included in the allowable range. In this case (YES in S120), it is determined that rotation speed sensor 240 is normal (S122).

  If the lead wire 244 of the rotation speed sensor 240 is cut, the output voltage V becomes smaller than the normal output voltage V (solid line) as shown by a broken line in FIG. In this case, as indicated by the alternate long and short dash line in FIG. 5A, output voltage V is lower than lower limit value V (L) (NO in S120), and rotation speed sensor 240 is determined to be abnormal. (S124) The warning lamp 250 is turned on and a code indicating that the rotation speed sensor 240 is abnormal is stored (S126).

  If the lead wire 244 and the shield wire 246 of the rotational speed sensor 240 are short-circuited, the output voltage V becomes larger than the upper limit value V (H) as shown by a two-dot chain line in FIG. NO), it is determined that the rotational speed sensor 240 is abnormal (S124), the warning lamp 250 is turned on, and a code indicating that the rotational speed sensor 240 is abnormal is stored (S126).

  As described above, in the abnormality determination device for the rotational speed sensor according to the present embodiment, the ECU determines the lower limit value V (L of the allowable range of the output voltage V based on the map stored in the ROM and the rotational speed of the engine. ) And an upper limit value V (H). The lower limit value V (L) and the upper limit value V (H) are calculated so as to increase as the engine speed increases and to increase the deviation from the normal output voltage. As a result, the allowable range of the output voltage V of the rotational speed sensor increases as the rotational speed of the engine increases. When the output voltage V of the rotational speed sensor is larger than the lower limit value V (L) and smaller than the upper limit value V (H), it is determined that the rotational speed sensor is normal. When the output voltage V is at least one of the case where the output voltage V is smaller than the lower limit value V (L) and the case where the output voltage V is larger than the upper limit value V (H), the rotational speed sensor is determined to be abnormal. As a result, the rotation speed sensor is normal, but the rotation speed of the engine is high, and the output voltage of the rotation speed sensor is high. The number sensor can be determined to be normal. As a result, it is possible to suppress erroneous determination that the rotational speed sensor is abnormal, and to accurately determine whether the rotational speed sensor is normal or abnormal.

<Second Embodiment>
The second embodiment of the present invention will be described with reference to FIGS. In the first embodiment described above, whether the rotational speed sensor is normal or abnormal is determined based on whether or not the output voltage V is included in the allowable range. The determination is based on the average value of the output voltage.

  Other configurations are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  With reference to FIG. 6, the control structure of the program executed by ECU 200 in the abnormality determination device for the rotational speed sensor according to the present invention will be described. S100 to S112 and S122 to S126 are the same as those in the first embodiment. Therefore, detailed description thereof will not be repeated here.

  In S200, ECU 200 acquires output voltage V of rotation speed sensor 240 for a predetermined time. In S202, ECU 200 calculates average voltage VA of output voltage V. In S204, ECU 200 determines whether or not calculated average voltage VA is the same as a predetermined average voltage V (0). If the issued average voltage VA is the same as predetermined average voltage V (0) (YES in S204), the process proceeds to S122. If not (NO in S204), the process proceeds to S124.

  The operation of ECU 200 in the abnormality determination device for the rotational speed sensor according to the present embodiment based on the above-described structure and flowchart will be described.

  When the output voltage V of the rotation speed sensor 240 is acquired for a predetermined time (S200), the average voltage VA of the output voltage V is calculated (S202). If the rotation speed sensor 240 is normal, the output voltage of the rotation speed sensor 240 alternately takes a positive value and a negative value as shown by a solid line in FIG. Therefore, even if the output voltage V of the rotational speed sensor 240 temporarily increases or decreases, the average voltage VA becomes 0 volts. Therefore, if average voltage VA is 0 volts (YES in S204), it is determined that rotation speed sensor 240 is normal (S122). Note that the average voltage when the rotational speed sensor 240 is normal is not limited to 0 volts, but may be other values.

  If the lead wire 244 and the shield wire 246 of the rotation speed sensor 240 are short-circuited and there is an abnormality in the rotation speed sensor 240, the time when the output voltage V of the rotation speed sensor 240 becomes a positive value as shown by a one-dot chain line in FIG. Is longer than the negative time, and the average voltage VA is greater than 0 volts. In this case (NO in S204), it is determined that the rotational speed sensor is abnormal (S124).

  If the lead wire 244 of the rotational speed sensor 240 is cut and there is an abnormality in the rotational speed sensor 240, although not shown, the time when the output voltage V of the rotational speed sensor 240 is negative is longer than the time when it is positive. The average voltage VA becomes smaller than 0 volts. In this case (NO in S204), it is determined that the rotational speed sensor is abnormal (S124).

As described above, in the abnormality determination device for the rotational speed sensor according to the present embodiment, the ECU acquires the output voltage V of the rotational speed sensor for a predetermined time, and calculates the average voltage VA.
If the rotational speed sensor is normal, the output voltage of the rotational speed sensor takes a positive value and a negative value alternately, so the average voltage VA becomes a predetermined value. Therefore, the ECU determines that the rotational speed sensor is normal if the average voltage VA is the same as a predetermined value, and determines that the rotational speed sensor is abnormal if the average voltage VA is different. Thus, although the rotation speed sensor is normal, the average voltage is determined in advance even when an output voltage having a large error from the actual output voltage is acquired because the engine rotation speed is high and the output voltage is high. If the voltage is the determined voltage, it can be determined that the rotational speed sensor is normal. As a result, it is possible to suppress an erroneous determination that the rotational speed sensor is abnormal, and to provide an abnormality determination device for the rotational speed sensor that can accurately determine whether the rotational speed sensor is normal or abnormal. be able to.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the engine and ECU of a vehicle by which the abnormality determination apparatus of the rotation speed sensor which concerns on the 1st Embodiment of this invention is mounted. It is a figure which shows the rotational speed sensor by which it is determined whether it is normal or abnormal by the abnormality determination apparatus of the rotational speed sensor which concerns on the 1st Embodiment of this invention. It is a figure which shows the map memorize | stored in ROM of ECU. 4 is a flowchart showing a control structure of a program executed by the ECU in the first embodiment of the present invention. It is a figure which shows the relationship between the output voltage at the time of normality, and the output voltage at the time of abnormality in the 1st Embodiment of this invention. In the 2nd Embodiment of this invention, it is a flowchart which shows the control structure of the program which ECU performs. It is a figure which shows the relationship between the output voltage at the time of normality, and the output voltage at the time of abnormality in the 2nd Embodiment of this invention.

Explanation of symbols

  100 engine, 118 timing rotor, 200 ECU, 202 ROM, 204 counter, 240 rotation speed sensor, 242 pickup coil, 244 lead wire, 246 shielded wire.

Claims (6)

A pickup coil, a lead wire connected to the pickup coil, and a shield wire surrounding the lead wire are provided, and an abnormality determination device for a rotational speed sensor that detects the rotational speed of the engine,
A state in which the engine speed is greater than a predetermined engine speed, a fluctuation in the engine engine speed is within a predetermined range, and a predetermined period has elapsed since the engine started. an acquisition means for acquiring the output voltage of the speed sensor in,
It is determined whether the rotation speed sensor is normal or abnormal based on whether or not the output voltage acquired by the acquisition means is included in an allowable range that increases as the rotation speed of the engine increases. An abnormality determination device for a rotational speed sensor, including a determination means. The determination means includes
When the output voltage acquired by the acquisition unit is included in the allowable range, it is determined that the rotation speed sensor is normal, and the output voltage acquired by the acquisition unit is not included in the allowable range The abnormality determination device for a rotation speed sensor according to claim 1, further comprising means for determining that the rotation speed sensor is abnormal. The abnormality determination device for the rotational speed sensor is:
Storage means for storing in advance the output voltage of the rotational speed sensor in correspondence with the rotational speed of the engine;
The abnormality determination device for a rotational speed sensor according to claim 1 or 2, further comprising means for calculating the allowable range based on the rotational speed of the engine and the output voltage stored in the storage means. The output voltage of the rotational speed sensor decreases as the rotational speed of the engine decreases,
The abnormality determination device for the rotational speed sensor is:
Means for comparing the engine speed with a predetermined speed;
The rotation speed sensor according to any one of claims 1 to 3 , further comprising means for prohibiting determination by the determination means when the rotation speed of the engine is lower than a predetermined rotation speed. Abnormality judgment device. The output voltage of the rotational speed sensor changes according to the rotational speed of the engine,
The abnormality determination device for the rotational speed sensor is:
Means for discriminating whether or not fluctuations in the engine speed in a predetermined period are within a predetermined range;
The rotation speed sensor according to any one of claims 1 to 3 , further comprising means for prohibiting determination by the determination means when fluctuations in the rotation speed of the engine are outside a predetermined range. Abnormality judgment device. The output voltage of the rotational speed sensor changes according to the rotational speed of the engine,
The abnormality determination device for the rotational speed sensor is:
Means for measuring a period since the engine was started;
Means for determining whether or not a predetermined period has elapsed since the start of the engine;
Period from startup of the engine, if not elapsed the predetermined period of time, and means for prohibiting the determination by the determination unit, according to any one of claims 1 to 3 An abnormality determination device for a rotational speed sensor.

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