JP7327323B2 - judgment device - Google Patents

Description

The present disclosure relates to a determination device that determines an abnormality in a drive mechanism of a vehicle.

When an abnormality occurs in the drive mechanism of a vehicle, it becomes difficult to drive the vehicle safely. Therefore, it is necessary to accurately determine whether or not an abnormality has occurred in the drive mechanism, and if an abnormality has occurred, notify the driver or the like to urge them to take action. The "driving mechanism" in the above is a mechanism that transmits the driving force generated by the internal combustion engine to the wheels and converts it into driving force for running. The drive mechanism includes, for example, a chain that a two-wheeled vehicle has, a transmission that a four-wheeled vehicle has, and wheels of wheels.

Patent Literature 1 listed below describes a configuration of a bearing device capable of detecting the eccentricity of a wheel among the abnormalities of the drive mechanism as described above. In this bearing device, a plurality of load sensors are arranged inside, and the presence or absence of eccentricity of the wheel is determined based on the signals from these sensors.

Further, Japanese Patent Laid-Open No. 2002-200010 describes a device for determining an abnormality of a drive mechanism by using an autocorrelation function from fluctuations in the number of revolutions of an internal combustion engine obtained by a crank angle sensor.

JP 2008-116241 A JP 2017-214857 A

If a dedicated sensor for detecting an abnormality in the drive mechanism is separately provided as in the device described in Patent Document 1, the cost of parts for the vehicle will increase. In addition, since it is necessary to provide a sensor for each portion where an abnormality may occur, the parts cost will further increase. Therefore, it is preferable to determine abnormality based on a signal from an existing sensor such as a crank angle sensor, as in the device described in Patent Document 2 above.

However, the determination method described in Patent Document 2 uses an autocorrelation function. For this reason, depending on the type and number of abnormalities that occur in the drive mechanism, it may be difficult to extract the effects of the abnormality in the drive mechanism from fluctuations in the number of revolutions, making it impossible to accurately determine whether there is an abnormality in the drive mechanism. It is thought that there is

An object of the present disclosure is to provide a determination device that can accurately determine an abnormality in a drive mechanism.

A determination device according to the present disclosure is a determination device (10) for determining an abnormality in a drive mechanism of a vehicle (MV), and includes a rotation speed acquisition unit (11) that repeatedly acquires the rotation speed of an internal combustion engine (100) of the vehicle. ), and a determination unit (12) that determines an abnormality of the drive mechanism based on the rotation speed acquired by the rotation speed acquisition unit. At the first timing when the crank angle of the internal combustion engine reaches the first angle, the value of the rotation speed acquired by the rotation speed acquisition unit is _α1 , and the crank angle advances from the first angle by a predetermined angle to a second angle. At the second timing, the value of the rotation speed acquired by the rotation speed acquisition unit is _α2 , and the crank angle is the third angle advanced by an integer multiple of 720 degrees from the first angle. At the timing, the value of the rotation speed acquired by the rotation speed acquisition unit is _α3 , and at the fourth timing when the crank angle reaches the fourth angle advanced by the integer multiple of 720 degrees from the second angle, rotation is performed. The value of the number of rotations acquired by the number acquisition unit is _α4 , and the average value of a plurality of number of rotations acquired by the number of rotations acquisition unit in the first period, which is the period before and after the first timing. is N ₁ , and in the second period, which is a period before and after the second timing, the average value of a plurality of rotation speeds acquired by the rotation speed acquisition unit is N ₂ , and the third timing is the center In the third period, which is a period before and after that, the average value of the plurality of rotation speeds acquired by the rotation speed acquisition unit is set to _N3 , and the fourth period is a period before and after the fourth timing. , when the average value of the plurality of rotation speeds acquired by the rotation speed acquisition unit is _N4 , the determination unit determines A represented by the following formula (1) and A represented by the following formula (2) A plurality of values of B are calculated for each number of revolutions obtained at different timings, and the difference between σ _A ² , which is the variance of A, and σ _B ² , which is the variance of B, is the abnormality of the drive mechanism judge.
A=(α ₄ −α ₃ )−(α ₂ −α ₁ ) Expression (1)
B=((α ₄ −N ₄ )−(α ₃ −N ₃ ))−((α ₂ −N ₂ )−(α ₁ −N ₁ )) Equation (2)

In the determination device configured as described above, the abnormality of the drive mechanism is determined based on the difference between the variance of A, σ _A ² , and the variance of B, σ _B ² . Since the plurality of A and B are calculated based on α ₁ and the like obtained at the timing when the crank angle of the internal combustion engine reaches a specific angle, there is almost no fluctuation due to the variation in the obtained timing. do not have.

However, the distribution of the plurality of A's is a distribution that reflects both the effect of an abnormality occurring in the drive mechanism and the effect of rotation speed fluctuations due to combustion occurring in sequence in each cylinder. On the other hand, since the distribution of the plurality of B is not greatly affected by the occurrence of an abnormality in the drive mechanism, the distribution greatly reflects the influence of the fluctuation in the rotation speed due to the combustion occurring sequentially in each cylinder.

Therefore, a value obtained by subtracting σ _B ² indicating the distribution of B from σ _A ² indicating the distribution of A can be used as a parameter reflecting the influence of an abnormality occurring in the drive mechanism. Therefore, in the judging device having the above configuration, the judging section judges the abnormality of the driving mechanism based on the difference between σ _A ² and σ _B ² . As a result, it is possible to accurately determine whether there is an abnormality in the drive mechanism without being affected by fluctuations in the engine speed caused by combustion occurring in sequence in each cylinder.

According to the present disclosure, a determination device is provided that can accurately determine an abnormality in a drive mechanism.

FIG. 1 is a diagram schematically showing the configuration of a determination device according to this embodiment and the configuration of a vehicle in which the determination device is mounted. FIG. 2 is a diagram schematically showing the configuration of a vehicle in which the determination device according to this embodiment is installed. FIG. 3 is a diagram showing an example of fluctuations in the number of revolutions of an internal combustion engine. FIG. 4 is a diagram showing an example of fluctuations in the number of revolutions of the internal combustion engine. FIG. 5 is a diagram showing examples of distributions of A and B, respectively. FIG. 6 is a diagram showing an example of fluctuations in the number of revolutions of the internal combustion engine. FIG. 7 is a diagram showing examples of distributions of A and B, respectively. FIG. 8 is a flow chart showing the flow of processing executed by the determination device according to this embodiment.

Hereinafter, this embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same constituent elements in each drawing are denoted by the same reference numerals as much as possible, and overlapping descriptions are omitted.

A determination device 10 according to the present embodiment is a device mounted on a vehicle MV, and is configured as a device for determining an abnormality in the drive mechanism of the vehicle MV. Before describing the determination device 10, the configuration of the vehicle MV will be described first with reference to FIG.

FIG. 1 schematically shows the configuration of a vehicle MV. The vehicle MV in this embodiment is configured as a two-wheeled vehicle that runs with the driving force of the internal combustion engine 100 . The reference numeral "150" in FIG. 1 indicates the drive wheel (that is, the rear wheel) of the two wheels of the vehicle MV. The wheels are hereinafter also referred to as "wheels 150". The vehicle MV may be a two-wheeled vehicle as in the present embodiment, but may be a four-wheeled vehicle.

The internal combustion engine 100 is a device for generating driving force necessary for running the vehicle MV. The internal combustion engine 100 of this embodiment 100 is configured as a four-cycle reciprocating engine having a plurality of cylinders 110 . FIG. 1 shows only one of the plurality of cylinders 110 of internal combustion engine 100 . The internal combustion engine 100 may be configured as a multi-cylinder engine as in the present embodiment, but may be configured as a single-cylinder engine.

Each cylinder 110 has a piston 111 housed inside the cylinder and a connecting rod 112 . The piston 111 is a member that moves up and down inside the cylinder as fuel is burned inside the cylinder 110 . Connecting rod 112 is a member that connects piston 111 and crankshaft 120 . The vertical motion of the piston 111 is converted into rotational motion of the crankshaft 120 via the connecting rod 112 .

The crankshaft 120 and the wheel 150 are connected by gears 131 and 131 and a chain 140 . The driving force of internal combustion engine 100, that is, the rotational force of crankshaft 1120 is transmitted to wheels 150 by gears 131 and 131 and chain 140 to rotate wheels 150. As shown in FIG.

As described above, the determination device 10 is configured as a device for determining an abnormality in the drive mechanism of the vehicle MV. The “driving mechanism” referred to here is a mechanism that transmits the driving force generated by the internal combustion engine 100 to the wheels 150 and converts it into driving force for running. In this embodiment, all of the gears 131, 131, the chain 140, and the wheels 150 correspond to the "drive mechanism".

Other configurations will be described. The vehicle MV is provided with a crank angle sensor 161 , a vehicle speed sensor 162 and an opening sensor 163 .

Crank angle sensor 161 is a sensor for detecting the number of rotations of internal combustion engine 100 per unit time, that is, the number of rotations of crankshaft 120 per unit time. "The number of revolutions of the internal combustion engine 100 (or the crankshaft 120) per unit time" is hereinafter simply referred to as "the number of revolutions of the internal combustion engine 100 (or the crankshaft 120)".

A plurality of projections (not shown) are formed on the outer peripheral surface of the crankshaft 120 along the circumferential direction. The crank angle sensor 161 is provided at a position close to the projection. Every time the crankshaft 120 rotates and each projection passes near the crank angle sensor 161, the crank angle sensor 161 outputs a pulse waveform signal. The waveform signal is transmitted to the determination device 10 . The determination device 10 can acquire the rotation speed of the internal combustion engine 100 based on the waveform signal. In addition, at a specific position on the outer peripheral surface of crankshaft 120, a "missing tooth portion" without the above protrusion is formed. The determination device 10 can detect the passage of the missing tooth portion based on the change in the waveform signal, and can also acquire the rotation angle (phase) of the crankshaft 120 . The rotation angle of crankshaft 120 is hereinafter also referred to as "crank angle".

The vehicle speed sensor 162 is a sensor for detecting the traveling speed of the vehicle MV. Vehicle speed sensor 162 is provided near wheel 150 and outputs a signal indicating the rotational speed of wheel 150 . The signal is transmitted to the determination device 10 .

The opening sensor 163 is a sensor for detecting the opening of the throttle valve 103 of the vehicle MV. As shown in FIG. 2, an internal combustion engine 100 is provided with an intake pipe 101 for supplying air for combustion and an exhaust pipe 102 for discharging exhaust gas produced by combustion. The throttle valve 103 is a valve provided in the middle of the intake pipe 101 and adjusts the flow rate of air supplied from the intake pipe 101 to the internal combustion engine 100 . The opening sensor 163 is provided near the throttle valve 103 and outputs a signal corresponding to the opening of the throttle valve 103 . The signal is transmitted to the determination device 10 . The opening sensor 163 may be built in the throttle valve 103 .

The configuration of the determination device 10 will be described with continued reference to FIG. The determination device 10 is configured as a computer system having a CPU, ROM, RAM, and the like. The determination device 10 includes a rotational speed acquisition unit 11, a determination unit 12, and a notification unit 13 as block elements representing its functions.

The rotation speed acquisition unit 11 is a part that performs processing for repeatedly acquiring the rotation speed of the internal combustion engine 100 . The rotation speed acquisition unit 11 repeatedly acquires the rotation speed of the internal combustion engine 100 based on the waveform signal transmitted from the crank angle sensor 161 . Specifically, the rotation speed acquisition unit 11 acquires the rotation speed of the internal combustion engine 100 based on the length of the period from the timing when one waveform signal is input to the timing when the next waveform signal is input. do. Alternatively, the rotational speed of the internal combustion engine 100 may be obtained based on the total length of the period in which a plurality of constant number of waveform signals are input. Such acquisition (that is, sampling) of the number of rotations is performed each time a preset predetermined control period elapses. This control cycle is preferably shorter than the rotation cycle of the internal combustion engine 100 so that a waveform shown in FIG.

Instead of the above aspect, for example, the number of revolutions may be acquired by the number of revolutions acquisition unit 11 each time a pulse waveform is input to the determination device 10 .

The determination unit 12 is a part that performs processing for determining abnormality of the drive mechanism based on the rotation speed acquired by the rotation speed acquisition unit 11 . Specific contents of the processing will be described later.

The notification unit 13 is a part that performs processing for notifying the result of determination by the determination unit 12 . As shown in FIG. 1, a vehicle MV is provided with a notification device 20 . The notification device 20 is a lamp provided at a position visible from the driver in the vehicle MV. When the determination unit 12 determines that there is an abnormality in the drive mechanism, the notification unit 13 notifies the driver of the fact by turning on the notification device 20 .

Instead of such a mode, for example, the notification unit 13 transmits a signal to a server installed at a position different from the vehicle MV, thereby notifying the user of the server that an abnormality has occurred in the drive mechanism. It is also possible to notify the The "user of the server" who receives the notification may be, for example, a person in charge of a dealer who sells or maintains the vehicle MV. Thus, the notification by the notification unit 13 may be made to the driver, or may be made to a person or device other than the driver.

An overview of the processing performed by the determination device 10 to determine the abnormality of the drive mechanism will be described. FIG. 3A shows an example of a waveform signal transmitted from the crank angle sensor 161 to the determination device 10 while the internal combustion engine 100 is operating. The upper part of FIG. 3(A) shows changes in four processes in one of the plurality of cylinders 110 of the internal combustion engine 100 when focusing on one of the cylinders 110 . As is well known, in cylinder 110, four processes of "compression", "expansion", "exhaust" and "intake" are repeated. In FIG. 3, for convenience of explanation, a unique number such as "(1)" or "(2)" for specifying each step is attached above the character string indicating each step.

In FIG. 3A, for example, the waveform signal is flat between (2) the expansion stroke and (3) the exhaust stroke. This indicates that the "missing tooth portion" formed on the outer peripheral surface of the crankshaft 120 passed near the crank angle sensor 161 at this timing.

FIG. 3B shows an example of count values of the above waveform signal. The count value represents the phase of rotation of the internal combustion engine 100, that is, the crank angle. The count value is reset when the missing tooth portion passes through the vicinity of the crank angle sensor 161 twice. In other words, the count value of the waveform signal is reset each time the crankshaft 120 rotates 720 degrees. Based on such a count value, it is possible to grasp which of the four processes each cylinder of the internal combustion engine 100 is in at each point in time.

FIG. 3(C) shows an example of temporal change in the rotation speed of the internal combustion engine 100 acquired by the rotation speed acquisition unit 11 . In addition, as described above, the rotational speed acquiring unit 11 repeatedly acquires the rotational speed each time a predetermined control period elapses. In other words, the number of revolutions acquired by the number of revolutions acquisition unit 11 is a set of discrete values that are periodically acquired. However, in FIG. 3(C), for ease of understanding, the graph is drawn as a curved line in which the number of rotations changes continuously.

The determination unit 12 first selects four pieces of data from among the plurality of rotation speeds acquired by the rotation speed acquisition unit 11 . In FIG. 3C, these four data are indicated as α ₁ , α ₂ , α ₃ and α ₄ respectively.

α ₁ is the value of the rotation speed acquired by the rotation speed acquisition unit 11 at the timing when the crank angle of the internal combustion engine 100 reaches the first angle. The above "first angle" is a preset angle, and this first angle is shown as "θ ₁ " in FIG. 3(B). The first angle is set, for example, as an angle advanced by a predetermined angle from the reference crank angle at which the intake stroke of (4) in FIG. 3 is started. The timing at which _α1 is acquired is hereinafter also referred to as “first timing”. In FIG. 3, the first timing at which _α1 is acquired is indicated as "t1".

α ₂ is the value of the rotation speed acquired by the rotation speed acquisition unit 11 at the timing when the crank angle of the internal combustion engine 100 reaches a second angle advanced by a predetermined angle from the first angle (θ ₁ ). be. In FIG. 3B, this second angle is indicated as "θ ₂ ". The above-mentioned "predetermined angle" is a preset angle, and is set as an angle of 360 degrees or less in this embodiment. Since the crank angle is reset every 720 degrees as described above, _θ2 may be smaller than _θ1 as in the example of FIG. 3(B). The timing at which _α2 is acquired is hereinafter also referred to as “second timing”. In FIG. 3, the second timing at which _α2 is acquired is indicated as "t2".

α ₃ is the rotation acquired by the rotation speed acquisition unit 11 at the timing when the crank angle of the internal combustion engine 100 reaches the third angle advanced by an integer multiple of 720 degrees from the first angle (θ ₁ ). is a numeric value. In this embodiment, 1 is set as the above-mentioned "integer", but a value different from 1 may be set. In FIG. 3B, this third angle is indicated as "θ ₃ ". The timing at which _α3 is acquired is hereinafter also referred to as “third timing”. In FIG. 3, the third timing at which _α3 is obtained is indicated as "t3".

α ₄ is the rotation acquired by the rotation speed acquisition unit 11 at the timing when the crank angle of the internal combustion engine 100 reaches the fourth angle advanced by an integer multiple of 720 degrees from the second angle (θ ₂ ). is a numeric value. In this embodiment, 1 is set as the above-mentioned "integer", but a value different from 1 may be set. In FIG. 3B, this fourth angle is indicated as "θ ₄ ". The timing at which _α4 is acquired is hereinafter also referred to as the “fourth timing”. In FIG. 3, the fourth timing at which _α4 is acquired is indicated as "t4".

It is preferable that the "integer multiple of 720 degrees" indicating the difference between the fourth angle and the second angle be matched with the "integral multiple of 720 degrees" indicating the difference between the third angle and the first angle.

After selecting the four pieces of data α ₁ , α ₂ , α ₃ , and α ₄ as described above, the determination unit 12 calculates a parameter “A” represented by the following equation (1).
A=(α ₄ −α ₃ )−(α ₂ −α ₁ ) Expression (1)

In the above example, the determination unit 12 selects _α1 from the data acquired at the timing of the intake stroke of (4) in FIG. 3, selects _α2 , _α3 , and _α4 based on the timing, Based on these, the above A is calculated.

Similarly, the determination unit 12 selects each of α ₁ , α ₂ , α ₃ , and α ₄ from data acquired at a timing different from the above example, and separately determines the above A based on these. calculate. Specifically, _α1 is selected from the data acquired at the timing of the compression step of (5) in FIG. In this case, unlike the above example, the first angle (θ ₁ ) at which α ₁ is obtained is based on the crank angle when the compression step (5) in FIG. is set as an angle advanced by a predetermined angle from .

α ₂ , α ₃ , and α ₄ are determined based on the acquisition timing of α ₁ as in the previous example. That is, α ₂ is the data acquired at the timing when the crank angle reaches the second angle (θ ₂ ) advanced by a predetermined angle from the current first angle (θ ₁ ), and α ₃ is the data obtained when the crank angle This is the data acquired at the timing when the third angle (θ ₃ ), which is an integral multiple of 720 degrees from the first angle (θ ₁ ) this time, is reached _. This data is obtained at the timing of the fourth angle (θ ₄ ), which is an integral multiple of 720 degrees from (θ ₂ ). The relative relationship between the acquisition timings of α ₁ , α ₂ , α ₃ and α ₄ is the same as the relative relationship between the acquisition timings of α ₁ , α ₂ , α ₃ and α ₄ in the previous example. is.

After that, the determination unit 12 selects each of α ₁ , α ₂ , α ₃ , and α ₄ from data acquired at a timing different from the above, and separately calculates the above A based on these. Specifically, α ₁ is obtained from the data obtained at the timing of the expansion step (6) in FIG. In this case, the first angle (θ ₁ ) at which α ₁ is obtained is an angle advanced by a predetermined angle from the reference crank angle when the expansion step (6) in FIG. 3 is started. will be set as α ₂ , α ₃ , and α ₄ are also determined based on the acquisition timing of α ₁ . The relative relationship between the acquisition timings of α ₁ , α ₂ , α ₃ , and α ₄ is the relative relationship between the acquisition timings of α ₁ , α ₂ , α ₃ , and α ₄ in the above two examples. are the same.

After that, the determination unit 12 acquires _α1 from the data acquired in each step (7), (8), ( ₉ ), etc. in FIG. , α ₂ , α ₃ , α ₄ are selected, and A is calculated based on these. By repeating such calculation of A, the determination unit 12 calculates a plurality of values of A according to Equation (1). A plurality of values of A calculated in this way are not necessarily the same value, but have a certain variation centering on 0. FIG.

In addition to calculating A as described above, the determining unit 12 calculates a parameter "B" represented by the following equation (2).
B=((α ₄ −N ₄ )−(α ₃ −N ₃ ))−((α ₂ −N ₂ )−(α ₁ −N ₁ )) Equation (2)

“N ₁ ” in the expression (2) is an average value of a plurality of rotation speeds acquired by the rotation speed acquisition unit 11 in a period around the first timing (t1) at which α ₁ is acquired. be. This period is hereinafter also referred to as a “first period”. In FIG. 3C, this first period is indicated as " _TM1 ". In this embodiment, the first period _TM1 is set as a period of length during which the crank angle changes by 720 degrees. That is, the first period (TM ₁ ) is set as a period in which the crank angle changes by 360 degrees around the first timing (t1).

“N ₂ ” in the expression (2) is an average value of a plurality of rotation speeds acquired by the rotation speed acquisition unit 11 in a period around the second timing (t2) at which α ₂ is acquired. be. This period is hereinafter also referred to as a “second period”. In FIG. 3C, this second period is indicated as "TM ₂ ". In this embodiment, the second period _TM2 is set as a period of length during which the crank angle changes by 720 degrees. That is, the second period (TM ₂ ) is set as a period in which the crank angle changes by 360 degrees around the second timing (t2).

“N ₃ ” in equation (2) is the average value of a plurality of rotation speeds acquired by the rotation speed acquisition unit 11 in a period around the third timing (t3) at which α ₃ is acquired. be. This period is hereinafter also referred to as a “third period”. In FIG. 3C, this third period is indicated as " _TM3 ". In this embodiment, _TM3 , which is the third period, is set as a period of length during which the crank angle changes by 720 degrees. That is, the third period (TM ₃ ) is set as a period in which the crank angle changes by 360 degrees around the third timing (t3).

“N ₄ ” in Equation (2) is the average value of a plurality of rotation speeds acquired by the rotation speed acquisition unit 11 in a period around the fourth timing (t4) at which α ₄ is acquired. be. This period is hereinafter also referred to as a “fourth period”. In FIG. 3C, this fourth period is indicated as "TM ₄ ". In this embodiment, _TM4 , which is the fourth period, is set as a period having a length during which the crank angle changes by 720 degrees. That is, the fourth period (TM ₄ ) is set as a period in which the crank angle changes by 360 degrees around the fourth timing (t4).

Similar to A described above, the determination unit 12 also calculates a plurality of values of B based on a plurality of α ₁ , α ₂ , α ₃ , and α ₄ obtained at different timings. In this way, the determination unit 12 calculates multiple values of A represented by Equation (1) and B represented by Equation (2) for each number of revolutions obtained at different timings.

A and B, each of which is calculated in plurality, are calculated based on _α1 and the like obtained at the timing when the crank angle of the internal combustion engine 100 reaches a specific angle, so they are based on variations in the obtained timing. Little change occurs.

The determining unit 12 calculates each of σ _A ² that is the variance of A that has been calculated multiple times and σ _B ² that is the variance of B that has been calculated multiple times.

If an abnormality due to deterioration or the like occurs in the drive mechanism, the driving force generated in the internal combustion engine 100 will not be smoothly transmitted. to be influenced. In addition, the rotation speed acquired by the rotation speed acquisition unit 11 is also affected by combustion occurring sequentially in the plurality of cylinders 110 of the internal combustion engine 100 . Therefore, σ _A ² , which is the variance of A, is a value that reflects the effects of both the abnormality in the drive mechanism and the fact that combustion occurs sequentially in each cylinder 110 .

On the other hand, in calculating B, as shown in equation (2), _N1 is subtracted from _α1 , N2 is subtracted from _α2 , _N3 is subtracted from _α3 , and _N3 is subtracted from _α4 . ₄ is subtracted. As described above, _N1 etc. is a value calculated as an average value of a period in which the crank angle changes by 360 degrees around the timing at which _α1 etc. is obtained. That is, N1 _and the like are calculated using the average value of the range in which the crank angle changes by 720 degrees, that is, the range in which combustion occurs once in all cylinders 110 of the internal combustion engine 100 . The distribution of B calculated using such _N1 etc. is not greatly affected by the occurrence of an abnormality in the drive mechanism, and is only affected by fluctuations in the rotation speed due to combustion occurring in sequence in each cylinder 110. close to the reflected distribution. As a result, σ _B ² , which is the variance of B, becomes a value close to a value that reflects only the effect of the sequential combustion in each cylinder 110 .

As described above, the value of the difference obtained by subtracting σ _B ² from σ _A ² can be used as a parameter that reflects the effect of an abnormality occurring in the drive mechanism. Therefore, the determination unit 12 in this embodiment determines abnormality of the drive mechanism based on the difference between σ _A ² and σ _B ² . Specifically, when the difference between σ _A ² and σ _B ² is greater than or equal to a predetermined threshold value, the determination unit 12 determines that there is an abnormality in the drive mechanism. According to this method, it is possible to accurately determine whether or not an abnormality has occurred not only when a single abnormality occurs in the drive mechanism, but also when multiple abnormalities occur simultaneously. becomes.

A line L11 in FIG. 4A is an example of a change in the rotation speed over time obtained by the rotation speed obtaining unit 11 when there is no abnormality in the drive mechanism. A line L12 in FIG. 4(A) is a change in the count value of the waveform signal from the crank angle sensor 161, and schematically shows a waveform similar to that shown in FIG. 3(B) for reference. It is a thing.

In FIG. 4(A), as in FIG. 3(C), the values of α ₁ , α 2 , α 3 and α ₄ acquired by the rotational speed acquisition unit 11 at each timing (t1, _t2 , _t3 , t4) is shown as a point on line L11.

Here, regarding the value of the rotation speed acquired by the rotation speed acquisition unit 11, the value of each rotation speed in a period in which the crank angle changes by 360 degrees around the timing at which the value is acquired. A value obtained by calculating an average value and subtracting the average value from the original rotation speed value will be referred to as "rotation speed'". For example, α ₁ −N ₁ described above corresponds to the number of revolutions′ when α ₁ is the original number of revolutions.

A line L21 in FIG. 4(B) is a graph showing a change in the rotation speed' when the values of the rotation speed shown in the line L11 in FIG. 4(A) are converted into the rotation speed'. It's becoming Line L22 in FIG. 4B is the same as line L12 in FIG. 4A. As shown in FIG. 4(B), the number of rotations ' (α ₁ -N 1, α ₂ -N _{2 , etc.} ) corresponding to α ₁ , α ₂ , α ₃ and α ₄ respectively is determined by each timing (t1 , t2, t3, t4) on the line L21.

As in the example shown in FIG. 4, when there is no abnormality in the drive mechanism, the line L11 indicating the change in the rotation speed and the line L21 indicating the change in the rotation speed' have a substantially constant period and amplitude. It becomes a graph that fluctuates with The variation is due to combustion occurring in each cylinder 110 in sequence. Lines L11 and L21 are both substantially flat graphs except for the component of the fluctuation.

As in the example shown in FIG. 4, the distribution of the plurality of A's calculated when there is no abnormality in the drive mechanism is the distribution shown by the line _LA in FIG. Also, the distribution of the plurality of Bs calculated at this time is the distribution shown by the line _LB in FIG. Also shown in FIG. 5 are the values of σ _A and σ _B , which are the standard deviations of A and B, respectively. As shown in FIG. 5, when there is no abnormality in the drive mechanism, the difference between the distributions of A and B is less likely to occur, so the value of σ _A ² −σ _B ² is a relatively small value. becomes. Theoretically, as shown in FIG. 5, the distribution of A and the distribution of B when there is no abnormality in the drive mechanism are the same, and the value of σ _A ² −σ _B ² is zero.

A line L11 in FIG. 6A is an example of a change in the rotation speed over time obtained by the rotation speed obtaining unit 11 when an abnormality has occurred in the drive mechanism. Line L12 in FIG. 6A is the same as line L12 in FIG. 4A. In FIG. 6(A), as in FIG. 4(A), the values of α ₁ , α 2 , α 3 and α ₄ acquired by the rotational speed acquiring unit 11 at each timing (t1, _t2 , _t3 , t4) is shown as a point on line L11.

A line L21 in FIG. 6(B) indicates a change in the rotational speed ' when the values of the rotational speed indicated by the line L11 in FIG. 6(A) are converted into the rotational speed '. It is a graph. Line L22 in FIG. 6B is the same as line L12 in FIG. 6A. In FIG. 6(B), as in FIG. 4(B), the number of rotations ' (α _{1 -N} 1, α ₂ -N _2, etc.) corresponding to each of α ₁ , α ₂ , α ₃ and α ₄ is It is shown as a value on line L21 at each timing (t1, t2, t3, t4).

As is clear from comparing FIG. 4 and FIG. 6, when there is an abnormality in the drive mechanism (FIG. 6), the line L11 representing the change in the rotation speed becomes a graph with relatively large undulations. Such an undulation is caused by an abnormality occurring in the drive mechanism, and the cycle of the fluctuation is larger than the cycle of fluctuation caused by combustion occurring sequentially in each cylinder 110. becomes.

In the graph of the number of revolutions' indicated by the line L21 in FIG. 6B, most of the undulation caused by the abnormality that occurred in the drive mechanism has been removed. Therefore, the line L21 in FIG. 6B has less undulation than the line L11 in FIG. 6A, and the graph is nearly flat like the line L21 in FIG. 4B.

As in the example shown in FIG. 6, the distribution of the plurality of A's calculated when there is an abnormality in the drive mechanism is the distribution shown by the line _LA in FIG. Also, the distribution of the plurality of Bs calculated at this time is the distribution shown by the line _LB in FIG. Similar to FIG. 5, FIG. 7 also shows the values of σ _A and σ _B , which are the standard deviations of A and B, respectively. As shown in FIG. 7, when there is an abnormality in the driving mechanism, a difference between the distributions of A and B is likely to occur, so the value of σ _A ² −σ _B ² is the same as in FIG. value is larger than in the case of

As described above, the determination unit 12 determines that an abnormality has occurred in the drive mechanism when the difference between σ _A ² and σ _B ² is greater than or equal to a predetermined threshold. The threshold value may be set to be larger than the value of σ _A ² −σ _B ² in the example of FIG. 5 and smaller than the value of σ _A ² −σ _B ² in the example of FIG.

A flow of specific processing executed by the determination device 10 in order to realize the determination by the method described above will be described with reference to the flowchart of FIG. 8 . A series of processes shown in FIG. 8 are executed by the determination device 10, for example, immediately after the vehicle MV is started. Instead of such a mode, the series of processes shown in FIG. 8 may be repeatedly executed by the determination device 10 each time a predetermined period elapses. There are no particular restrictions on the timing or cycle of execution of the process.

In the first step S<b>01 of the process, the process of repeatedly acquiring the rotation speed of the internal combustion engine 100 is started by the rotation speed acquisition unit 11 . In step S02 following step S01, it is determined whether or not a predetermined period of time has elapsed since the process of step S01 was performed. This “predetermined period” is a period set in advance as a period necessary for the number of rotations obtaining unit 11 to obtain a sufficient number of rotations. If the predetermined period has not yet passed, the process of step S02 is executed again. When the predetermined time has passed, after stopping acquisition of the rotation speed by the rotation speed acquisition unit 11, the process proceeds to step S03.

In step S03, after step S01, it is determined whether or not a stable condition has been established over the entire period during which the number of rotations was acquired by the number of rotations acquiring unit 11. FIG. The “stability condition” is a condition set in advance as a condition that the vehicle MV should satisfy when it is determined that there is an abnormality in the drive mechanism. In this embodiment, this stable condition is set as a condition that the traveling speed of the vehicle MV is equal to or higher than a predetermined threshold speed.

When the vehicle MV is traveling on an uneven road surface, the number of revolutions acquired by the number of revolutions acquiring unit 11 fluctuates, so that it is possible to accurately determine an abnormality of the drive mechanism based on the number of revolutions. it gets harder. However, when the traveling speed of the vehicle MV is relatively high, it is unlikely that the road surface on which the vehicle is traveling is a "rough road surface". For this reason, in the present embodiment, an abnormality in the drive mechanism is determined based only on the rotation speed data acquired when the stability condition that the traveling speed of the vehicle MV is equal to or higher than a predetermined threshold speed is satisfied. I am planning to As a result, the abnormality of the drive mechanism can be accurately determined without being affected by the road surface condition.

A condition different from the above may be set as the stable condition. For example, a condition that the variation in the running speed of the vehicle MV is within a predetermined range may be set as the stability condition. A condition that the variation in the degree of opening of the throttle valve 103 detected by the degree of opening sensor 163 is within a predetermined range may be set as the stability condition. By setting such a stable condition, it is possible to accurately determine the abnormality of the drive mechanism.

If it is determined in step S03 that the stability condition has not been established, the processes after step S01 are executed again. If it is determined that the stable condition has been established, the process proceeds to step S04.

In step S04, the values of σ _A ² and σ _B ² described above are calculated based on the rotational speed data acquired in step S01 and subsequent steps. Since the calculation method has already been explained, it is omitted here.

In step S05 following step S04, it is determined whether or not the value of σ _A ² -σ _B ² is equal to or greater than a threshold. If the value of σ _A ² -σ _B ² is greater than or equal to the threshold, the process proceeds to step S06. In step S06, 1 is added to the counter CT. The “counter CT” is a variable for counting the number of consecutive determinations that “the value of σ _A ² −σ _B ² is greater than or equal to the threshold value”. The value of the counter CT is stored in a non-volatile memory (not shown) of the determination device 10 .

In step S07 following step S06, it is determined whether or not the value of the counter CT is 3 or more. When the value of the counter CT is 3 or more, the process proceeds to step S08. In step S08, the determination unit 12 determines that an abnormality has occurred in the drive mechanism.

In step S<b>09 following step S<b>08 , the notification unit 13 performs a process of notifying the determination result of the determination unit 12 . As described above, the notification unit 13 notifies the driver that an abnormality has occurred by turning on the notification device 20 .

In step S05, if the value of σ _A ² -σ _B ² is less than the threshold, the process proceeds to step S10. In step S10, processing for resetting the value of the counter CT to 0 is performed. After that, the process moves to step S11. In step S11, the determination unit 12 determines that there is no abnormality in the drive mechanism. In this case, the notification by the notification unit 13 is not performed.

In step S07, when the value of the counter CT is less than 3, the process proceeds to step S11. In step S11, as described above, the determination unit 12 determines that there is no abnormality in the drive mechanism.

As described above, the determination unit 12 in the present embodiment determines that there is an abnormality in the drive mechanism when the difference between σ _A ² and σ _B ² becomes equal to or greater than the threshold value three times in succession. On the other hand, even if the difference between σ _A ² and σ _B ² is equal to or greater than the threshold, if the number of consecutive times the difference is equal to or greater than the threshold is less than 3, it is determined that there is no abnormality in the drive mechanism. do. By adopting such a configuration, it is possible to prevent erroneous determination by the determination unit 12 due to temporary rotation speed vibration caused by a cause other than an abnormality in the drive mechanism.

The condition of "three times" used for the determination in step S07 may be changed as appropriate. Also, if the occurrence of an erroneous determination does not pose a problem, the condition may be set to "once". That is, if the difference between σ _A ² and σ _B ² becomes equal to or greater than the threshold even once, it may be determined that there is an abnormality in the drive system.

Appropriate changes may be added to the processing described above. For example, the method of calculating multiple A's may be changed.

As described with reference to FIG. 3, in this embodiment, first, A is calculated based on α ₁ , α ₂ , α ₃ , and α ₄ acquired at each timing shown in FIG. 3(B). After that, the determination unit 12 acquires α ₁ from the data acquired at the timing of the compression step of (5) in FIG. 3, and selects α ₂ , α ₃ and α ₄ based on the acquisition timing of α ₁ . , A is calculated based on these.

Instead of such a method, for example, after calculating A based on α ₁ , α ₂ , α ₃ , and α ₄ acquired at the timing shown in FIG. Obtain α ₁ from the data obtained at the timing of the intake stroke of (12) in (12), select α ₂ , α ₃ , and α ₄ based on the acquisition timing of α ₁ , and calculate A based on these You can do it. In this case, α ₁ will always be selected from data acquired at the timing of the intake stroke, and α ₂ will always be selected from data acquired at the timing of the compression stroke.

In other words, the first timing is set as the timing within the period when the cylinder 110 is in the intake stroke, and the second timing is set as the timing within the period when the cylinder 110 is in the compression stroke. Become. As a result, the third timing is set as the timing within the period when the cylinder 110 is in the intake stroke, and the fourth timing is set as the timing within the period when the cylinder 110 is in the compression stroke. It will happen.

The period of the intake stroke and the compression stroke is relatively less affected by the combustion variation in the cylinder 110 than the period of the expansion stroke and the exhaust stroke. Therefore, as in the above example, α ₁ , α ₂ , α ₃ , and α ₄ are selected from the rotation speed data acquired during the intake stroke and compression stroke. , it is possible to accurately determine the abnormality of the drive mechanism. Such a configuration is particularly effective when internal combustion engine 100 is a single-cylinder engine.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples by those skilled in the art are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each specific example described above and its arrangement, conditions, shape, etc. are not limited to those illustrated and can be changed as appropriate. As long as there is no technical contradiction, the combination of the elements included in the specific examples described above can be changed as appropriate.

The control apparatus and control method described in the present disclosure are provided by one or more dedicated processors provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. It may be implemented by a computer. The control apparatus and control method described in this disclosure may be implemented by a special purpose computer provided by configuring a processor including one or more special purpose hardware logic circuits. The control apparatus and control method described in the present disclosure are configured by a combination of a processor and memory programmed to perform one or more functions and a processor including one or more hardware logic circuits. It may be implemented by one or more special purpose computers. The computer program may be stored as computer-executable instructions on a computer-readable non-transitional tangible storage medium. Dedicated hardware logic circuits and hardware logic circuits may be implemented by digital circuits containing multiple logic circuits or by analog circuits.

10: Determination device 11: Rotation speed acquisition unit 12: Determination unit MV: Vehicle 100: Internal combustion engine

Claims (10)

A determination device (10) for determining an abnormality of a drive mechanism in a vehicle (MV),
a rotation speed acquisition unit (11) that repeatedly acquires the rotation speed of an internal combustion engine (100) of the vehicle;
a determination unit (12) that determines an abnormality of the drive mechanism based on the rotation speed acquired by the rotation speed acquisition unit;
At a first timing when the crank angle of the internal combustion engine reaches the first angle, α ₁ is the value of the rotation speed acquired by the rotation speed acquisition unit,
At a second timing when the crank angle becomes a second angle advanced by a predetermined angle from the first angle, _α2 is the rotation speed value obtained by the rotation speed obtaining unit,
At a third timing when the crank angle becomes a third angle advanced by an integral multiple of 720 degrees from the first angle, the rotation speed value obtained by the rotation speed obtaining unit is _α3 ,
At a fourth timing when the crank angle becomes a fourth angle advanced by the integral multiple of 720 degrees from the second angle, the value of the rotation speed acquired by the rotation speed acquisition unit is _α4 ,
In the first period, which is a period before and after the first timing, the average value of the plurality of rotation speeds acquired by the rotation speed acquisition unit is set to _N1 ,
In the second period, which is a period before and after the second timing, the average value of the plurality of rotation speeds acquired by the rotation speed acquisition unit is set to _N2 ,
In the third period, which is a period before and after the third timing, the average value of the plurality of rotation speeds acquired by the rotation speed acquisition unit is set to _N3 ,
In the fourth period, which is a period before and after the fourth timing, when the average value of a plurality of rotation speeds acquired by the rotation speed acquisition unit is _N4 ,
The determination unit calculates a plurality of A represented by the following formula (1) and B represented by the following formula (2) for each number of revolutions obtained at different timings,
A=(α ₄ −α ₃ )−(α ₂ −α ₁ ) Expression (1)
B=((α ₄ −N ₄ )−(α ₃ −N ₃ ))−((α ₂ −N ₂ )−(α ₁ −N ₁ )) Equation (2)
A determination device for determining abnormality of the drive mechanism based on a difference between σ _A ² that is the variance of A and σ _B ² that is the variance of B. 2. The determination according to claim 1, wherein each of said first period, said second period, said third period, and said fourth period is set as a period having a length during which said crank angle changes by 720 degrees. Device. The determination device is
3. The determination device according to claim 1, wherein abnormality of said drive mechanism is determined based on the number of revolutions acquired by said number of revolutions acquisition unit when a predetermined stability condition is satisfied. 4. The determination device according to claim 3, wherein said stable condition is set as a condition that the traveling speed of said vehicle is equal to or higher than a predetermined threshold speed. 4. The determination device according to claim 3, wherein said stable condition is set as a condition that variation in running speed of said vehicle is within a predetermined range. 4. The determination device according to claim 3, wherein said stable condition is set as a condition that a variation in opening of a throttle valve (103) of said vehicle is within a predetermined range. The determination unit is
The determination device according to any one of claims 1 to 6, which determines that an abnormality has occurred in said drive mechanism when a difference between said σ _A ² and said σ _B ² is equal to or greater than a threshold value. The determination unit is
8. The determination device according to claim 7, which determines that an abnormality has occurred in said drive mechanism when the difference between said σ _A ² and said σ _B ² is equal to or greater than said threshold value consecutively for a predetermined number of times. The determination device according to any one of claims 1 to 8, further comprising a notification section (13) that reports a result of determination by said determination section. The first timing is set as timing within a period in which a cylinder of the internal combustion engine is in an intake stroke,
10. The determination device according to any one of claims 1 to 9, wherein said second timing is set as timing within a period in which said cylinder is in a compression stroke.

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