Belt slip detection device in vehicle

Abstract

To more accurately and early detect slip of a belt.SOLUTION: A belt slip detection device (100) is used in a vehicle including a first pulley (5), a second pulley (6), a ring-shaped belt (7) wound around the first pulley (5) and the second pulley (6), an electric motor (2) connected to the first pulley (5) and a battery (4) that supplies electric power to the electric motor (2). The belt slip detection device (100) includes: decision means (102) that decides a threshold value for determining presence / absence of slip of the belt (7) in accordance with an index indicating the state of the battery (4); and determination means (103) that determines presence / absence of the slip of the belt (7) on the basis of a determined value changing depending on a difference between the rotational frequency of the first pulley (5) and the rotational frequency of the second pulley (6) and the threshold value decided by the decision means (102).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a belt slip detection device in a vehicle. [Background technology]

[0002] Patent Document 1 discloses that in an automobile equipped with an engine and a generator motor that starts the engine, which are connected via a belt and rotate in tandem, slippage of the belt is detected based on the rotational speed of the generator motor and a conversion value obtained by multiplying the rotational speed of the engine by the ratio of the diameter of the generator motor pulley to the diameter of the engine pulley. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-196819 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the driving force of the electric motor that starts the engine decreases, the engine speed and the electric motor speed become closer when the belt slips, and the difference between them becomes difficult to occur. As the belt deteriorates, the belt may slip even with a small driving force. In Patent Document 1, the threshold value for determining belt slippage is set to a constant value, so that in a state where the difference between the engine speed and the electric motor speed is difficult to occur, such as when the electric motor is driven at low speed, it may not be possible to detect belt slippage early.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to detect belt slippage more reliably and at an early stage. [Means for solving the problem]

[0006] The belt slippage detection device in a vehicle of the present invention is a belt slippage detection device in a vehicle equipped with a first pulley, a second pulley, a ring-shaped belt stretched between the first pulley and the second pulley, an electric motor connected to the first pulley, and a battery that supplies power to the electric motor, and is characterized in that it is equipped with a determination means for determining a threshold for determining whether or not the belt is slipping based on an index representing the state of the battery, and a judgment means for determining whether or not the belt is slipping based on a determined value that changes depending on the difference between the rotation speed of the first pulley and the rotation speed of the second pulley, and the threshold determined by the determination means. Effect of the Invention

[0007] According to the present invention, belt slippage can be detected more reliably and at an early stage. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a schematic configuration of a main part of an automobile according to an embodiment of the present invention; [Diagram 2] 4 is a flowchart showing a process executed by a belt slippage detection device according to an embodiment. [Diagram 3] FIG. 4 is a diagram for explaining a slip determination threshold value. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A belt slippage detection device (100) according to one embodiment of the present invention is a belt slippage detection device (100) for a vehicle including a first pulley (5), a second pulley (6), a ring-shaped belt (7) stretched between the first pulley (5) and the second pulley (6), an electric motor (2) connected to the first pulley (5), and a battery (4) supplying power to the electric motor (2), and includes a determination means (102) for determining a threshold value for determining the presence or absence of slippage of the belt (7) according to an index representing the state of the battery (4), and a determination means (103) for determining the presence or absence of slippage of the belt (7) based on a determined value that changes according to the difference between the rotation speed of the first pulley (5) and the rotation speed of the second pulley (6) and the threshold value determined by the determination means (102). This makes it possible to detect slippage of the belt (7) more reliably and at an early stage. EXAMPLES

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of a main part of an automobile, which is a vehicle according to the embodiment. As shown in FIG. 1, an automobile is equipped with an engine 1, which is an internal combustion engine, an ISG (Integrated Starter Generator) 2, which is a generator motor, a starter motor 3, and a battery 4. A ring-shaped belt 7 is wound around a pulley 5 (called a first pulley) connected to the ISG 2 and a pulley 6 (called a second pulley) connected to a crankshaft of the engine 1. The power output by the engine 1 is changed in speed by a transmission (not shown) and transmitted to the driving wheels of the automobile. The ISG 2 functions as a starting device and a charging device for restarting the engine 1 during idling stop. The starter motor 3 is a starting device that starts the engine 1. The battery 4 supplies power to the ISG 2, the starter motor 3, the ignition plugs of the engine 1, etc., and is charged by the ISG 2.

[0011] The automobile is also equipped with an ECU (Electronic Control Unit) 100 that electronically controls each part. The ECU 100 performs, for example, fuel supply control and ignition timing control for the engine 1. The ECU 100 is configured by a computer unit that includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory that stores backup data, etc., an input port, and an output port.

[0012] In this embodiment, the ECU 100 functions as a belt slippage detection device to which the present invention is applied. The following mainly describes the function of the belt slippage detection device. The ECU 100 includes an acquisition unit 101, a decision unit 102, a judgment unit 103, and a processing unit 104, and functions as a belt slippage detection device.

[0013] The acquisition unit 101 acquires the rotation speed of the ISG2, which becomes the rotation speed ω_A of the first pulley 5, and the rotation speed of the engine 1, which becomes the rotation speed ω_B of the second pulley 6. For example, the ECU 100 receives the rotation speed of the ISG2 through communication with the ISG2, thereby acquiring the rotation speed of the ISG2. Also, the ECU 100 receives crank angle information from a crank sensor attached to the engine 1, and calculates the rotation speed of the engine 1 using the crank angle information, thereby acquiring the rotation speed of the engine 1.

[0014] The determination unit 102 determines a threshold value used by the determination unit 103, that is, a slippage determination threshold value ω_thr that is a threshold value for determining whether or not the belt 7 is slipping, according to an index that indicates the state of the battery 4. Specifically, the battery voltage is used as an index representing the state of the battery 4. The determination unit 102 acquires the battery voltage, and determines the slippage determination threshold ω_thr so ​​as to lower the level at which slippage of the belt 7 is detected when the battery voltage is low. In this embodiment, as shown in Fig. 3(a), when the battery voltage exceeds a predetermined threshold V_thr, the slippage determination threshold ω_thr is set to ω_thr=ω_thr1, and when the battery voltage is equal to or lower than the threshold V_thr, the slippage determination threshold ω_thr is set to ω_thr2 (<ω_thr1).

[0015] The judgment unit 103 judges whether or not the belt 7 is slipping based on a judged value that changes depending on the difference between the rotation speed ω_A of the first pulley 5 and the rotation speed ω_B of the second pulley 6, and the slippage judgment threshold value ω_thr determined by the determination unit 102. Specifically, when no slippage of the belt 7 occurs, the following formula (1) holds. ω_A=ω_B×d_B / d_A (1) ω_A: Number of revolutions of the first pulley 5 ω_B: Number of revolutions of the second pulley 6 d_A: pulley diameter of the first pulley 5 d_B: Pulley diameter of the second pulley 6 In this embodiment, the judgment unit 103 uses ω_A-ω_B×d_B / d_A as a judged value and judges that slippage of the belt 7 is occurring when ω_A-ω_B×d_B / d_A≧ω_thr. The slippage judgment threshold ω_thr is ω_thr1 or ω_thr2 determined by the decision unit 102. When the battery voltage is low, the slippage judgment threshold ω_thr is reduced (changing from ω_thr1 to ω_thr2), thereby lowering the level at which slippage of the belt 7 is detected. Lowering the level at which slippage is detected means making it easier to detect slippage.

[0016] The processing unit 104 executes a predetermined process in response to the determination unit 103 determining that slippage of the belt 7 has occurred. For example, the processing unit 104 notifies the user that belt slippage has been detected by using a display unit or a sound generating unit installed in the vehicle. The processing unit 104 may also restart the engine 1 using the starter motor 3 instead of the ISG 2, or prohibit idling stop.

[0017] 2 is a flowchart showing a process executed by the ECU 100 functioning as a belt slip detection device when the engine 1 is restarted by the ISG 2. In step S1, the determination unit 102 acquires a battery voltage. In this embodiment, the ISG2 is driven in step S3, which will be described later, and in step S1, the battery voltage before the ISG2 is driven is acquired.

[0018] In step S2, the determination unit 102 determines the slippage threshold ω_thr according to the battery voltage acquired in step S1. As shown in Fig. 3(a), when the battery voltage exceeds the threshold V_thr, the determination unit 102 sets the slippage determination threshold ω_thr=ω_thr1, and when the battery voltage is equal to or lower than the threshold V_thr, sets the slippage determination threshold ω_thr=ω_thr2 (<ω_thr1).

[0019] In step S3, ECU 100 drives ISG2.

[0020] In step S4, the determination unit 103 performs slippage determination using the slippage determination threshold ω_thr (=ω_thr1 or ω_thr2) determined in step S2. The determination unit 103 determines that slippage of the belt 7 is occurring when ω_A-ω_B×d_B / d_A≧ω_thr. If it is determined that slippage of the belt 7 is occurring, the process proceeds to step S5, and if it is determined that slippage of the belt 7 is not occurring, the process exits this flowchart.

[0021] In step S5, in response to the determination in step S4 that slippage of the belt 7 has occurred, the processing unit 104 executes predetermined processing, such as notifying the user, restarting the engine 1 using the starter motor 3, prohibiting idling stop, etc.

[0022] As described above, when the battery voltage is low and the driving force of ISG2 is reduced, by determining the slippage judgment threshold ω_thr so ​​as to lower the level at which slippage of belt 7 is detected, it is possible to detect slippage of belt 7 more reliably and earlier. In the past, when the battery deteriorated and the vehicle was replaced at a dealer, belt slippage due to a large driving force was detected after the battery replacement, which required another visit to the dealer to inspect and replace the belt. However, by applying the present invention, it is possible to carry out all the procedures at once.

[0023] In this embodiment, the battery voltage is used as an index representing the state of the battery 4, but instead, the depth of discharge (DOD) can be used. The DOD can be calculated by recording the charge and discharge amount of the battery 4. The determination unit 102 acquires the DOD and determines the slippage determination threshold ω_thr so ​​as to lower the level at which slippage of the belt 7 is detected when the DOD is small. That is, as in the case of the battery voltage, as shown in FIG. 3(b), when the DOD exceeds a predetermined threshold D_thr, the slippage determination threshold ω_thr=ω_thr1, and when the DOD is equal to or less than the threshold D_thr, the slippage determination threshold ω_thr=ω_thr2 (<ω_thr1). In this case, too, when the DOD is small and the driving force of the ISG2 is reduced, the slippage of the belt 7 can be detected more reliably and earlier by determining the slippage determination threshold ω_thr so ​​as to lower the level at which slippage of the belt 7 is detected. Both the battery voltage and the DOD may be used as indicators of the state of the battery 4. In this case, the level for detecting slippage of the belt 7 tends to be lowered when the battery voltage is low or when the DOD is small. The battery voltage, the DOD, and the slippage determination threshold value ω_thr may be mapped or tabulated in advance, and the slippage determination threshold value ω_thr may be read out from the map or table. Also, as an index representing the state of the battery 4, for example, the minimum battery voltage at the previous start of the engine 1 may be used.

[0024] In the present embodiment, the ISG2 is described as the electric motor of the present invention, but the present invention is not limited to this. For example, if the starter motor is connected to the engine via a belt, the starter motor may be used as the electric motor of the present invention.

[0025] Although the embodiments of the present invention have been described in detail above with reference to the drawings, each embodiment merely shows a specific example of the implementation of the present invention. The technical scope of the present invention is not limited to each embodiment. Various modifications of the present invention are possible without departing from the spirit of the present invention, and these modifications are also included in the technical scope of the present invention. A belt slippage detection device to which the present invention is applied is configured by a computer device equipped with, for example, a CPU, ROM, RAM, etc., and the functions of each means are realized by the CPU executing a predetermined program stored, for example, in the ROM. [Explanation of symbols]

[0026] 1: engine, 2: ISG, 3: starter motor, 4: battery, 5: first pulley, 6: second pulley, 7: belt, 100: ECU, 101: acquisition unit, 102: decision unit, 103: judgment unit, 104: processing unit

Claims

1. A belt slip detection device for a vehicle including a first pulley, a second pulley, a ring-shaped belt looped between the first pulley and the second pulley, an electric motor connected to the first pulley, and a battery that supplies power to the electric motor, a determination means for determining a threshold value for determining whether or not the belt is slipping in response to an index representing the state of the battery; A belt slippage detection device comprising: a judgment means for judging whether or not the belt is slipping based on a judged value that changes depending on the difference between the rotation speed of the first pulley and the rotation speed of the second pulley and the threshold value determined by the determination means.

2. The battery voltage is used as the index, 2. The belt slippage detection device according to claim 1, wherein the determining means determines the threshold value so as to lower a level at which the belt slippage is detected when a battery voltage is low.

3. The depth of discharge is used as the index, 3. The belt slippage detection device according to claim 1, wherein the determining means determines the threshold value so as to lower a level for detecting slippage of the belt when the depth of discharge is small.

4. the vehicle includes an internal combustion engine connected to the second pulley; 3. The belt slip detection device according to claim 1, wherein the electric motor functions as a starter for the internal combustion engine.

Images