Vehicle state detection device, vehicle, and vehicle state detection method

Abstract

To provide a vehicle state detection device which can detect a state of an internal combustion engine, and to provide a vehicle and a vehicle state detection method.SOLUTION: A vehicle state detection device of a hybrid vehicle according to one embodiment detects, in a hybrid vehicle including an internal combustion engine and a first motor which generates electric power by the internal combustion engine, a state of the internal combustion engine based on an electric generation index indicating electric power generated by the first motor.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vehicle state detection device, a vehicle, and a vehicle state detection method.

Background Art

[0002] In vehicles such as trucks, hybrid electric vehicles (HEVs) that use an internal combustion engine and a motor as drive sources are known. In such hybrid electric vehicles, technologies have been developed to drive a motor for power generation by an internal combustion engine and supply electric power to a drive motor that generates driving force for the vehicle.

[0003] For example, a vehicle includes an internal combustion engine, a first motor that serves as a generator, a second motor for driving, a clutch disposed between the first motor and the second motor, and a battery. The vehicle is controlled to operate in a plurality of different driving modes, such as a driving mode by the second motor and a driving mode using both the second motor and the internal combustion engine, by switching the connection state of the clutch.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In such vehicles, there is a need for a technology to detect changes in the state of the internal combustion engine, such as abnormal combustion due to problems in the combustion chamber in each cylinder of the internal combustion engine.

[0006] An object of the present invention is to provide a vehicle state detection device, a vehicle, and a vehicle state detection method that can detect the state of an internal combustion engine.

Means for Solving the Problems

[0007] In a hybrid vehicle including an internal combustion engine and a first motor that generates electricity by the internal combustion engine, the state of the internal combustion engine is detected based on a power generation index indicating the power generation power generated by the first motor.

[0008] A hybrid vehicle according to another embodiment includes an internal combustion engine, a first motor connected to the internal combustion engine, a detection unit that operates the internal combustion engine and detects a power generation index indicating the power generation power generated by the first motor, and a vehicle state detection unit that detects the state of the internal combustion engine based on the power generation index.

[0009] A vehicle state detection method for a hybrid vehicle according to another embodiment includes, in a hybrid vehicle including an internal combustion engine and a first motor that generates electricity by the internal combustion engine, detecting a power generation index indicating the power generation power generated by the first motor, and detecting the state of the internal combustion engine based on the power generation index. It includes.

Effect of the Invention

[0010] According to the present invention, it is possible to provide a vehicle state detection device, a vehicle, and a vehicle state detection method capable of detecting the state of an internal combustion engine.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0012] Hereinafter, the vehicle 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a block diagram showing the configuration of the vehicle 10. FIG. 2 is an explanatory diagram showing a part of the configuration of the vehicle 10. FIG. 3 is a flowchart of the vehicle state detection process according to the present embodiment. FIG. 4 is a waveform diagram of the generated power and the crank angle, showing the waveform of the generated power and the crank angle waveform superimposed in synchronization. In each figure, for the sake of explanation, the configuration is appropriately enlarged, reduced, or omitted.

[0013] As shown in FIGS. 1 and 2, the vehicle 10 is a series-parallel hybrid vehicle (HEV) equipped with an internal combustion engine 12, a first motor 13, and a second motor 15 as drive sources. The vehicle 10 is, for example, a truck.

[0014] The vehicle 10 includes a battery 11, an internal combustion engine 12, a first motor 13, a clutch 14 as a switching device, a second motor 15, a running unit 16, and a control unit 17.

[0015] The battery 11 is the power source of the vehicle 10. The battery 11 is connected to the first motor 13 and the second motor 15 via an inverter, respectively. For example, as the battery 11, a lithium-ion battery, a solid lithium-ion battery, a graphene secondary battery, or the like is used. For example, the battery 11 includes a battery module having a plurality of battery cells.

[0016] The internal combustion engine 12 is an engine such as a diesel engine or a gasoline engine. The internal combustion engine 12 is, for example, a multi-cylinder engine having a plurality of cylinders 12a to 12d. Each of the cylinders 12a to 12d has a fuel injection valve and is connected to a fuel tank. The internal combustion engine 12 is supplied with fuel from the fuel tank and generates power (torque) that becomes driving force by operating. The opening and closing of the fuel injection valves of the cylinders 12a to 12d of the internal combustion engine 12, the supply amount and timing of the fuel are configured to be controllable by the control unit 17.

[0017] The internal combustion engine 12 is connected to the traveling unit 16 via a clutch 14 and drives the traveling unit 16. Further, the internal combustion engine 12 is connected to the first motor 13 and drives the first motor 13 to generate electricity.

[0018] The internal combustion engine 12 is provided with a crank angle sensor 121 that measures the crank angle of the internal combustion engine 12. The crank angle sensor 121 detects the reference position, rotation angle, and rotation speed of the crankshaft of the internal combustion engine 12 and outputs pulses as a crank angle signal at every predetermined crank angle. For example, as the crank angle sensor 121, an optical or electromagnetic sensor is used. For example, the crank angle waveform W3 measured by the crank angle sensor 121 is a waveform having a pulse waveform every 180°, as shown in FIG. 4. For example, the crank angle waveform W3 has one pulse waveform in each of the crank angle ranges corresponding to the three cylinders 12a to 12c, and has two pulse waveforms in the crank angle range corresponding to the final fourth cylinder 12d.

[0019] The first motor 13 includes, for example, a motor case, a stator fixed to the motor case, and a rotor fixed to a shaft pivotally supported by the motor case. For example, the first motor 13 is connected to the battery 11 via an inverter.

[0020] The main shaft of the first motor 13 is connected to the internal combustion engine 12. The first motor 13 is configured to be able to generate electricity by the power of the internal combustion engine 12. That is, the first motor 13 functions as a generator when a rotational force is input from the internal combustion engine 12 to the main shaft. Further, the first motor 13 charges the battery 11 with the electric power generated by absorbing the torque of the internal combustion engine 12.

[0021] The first motor 13 may function as a drive motor that drives the traveling unit 16 by being supplied with electric power from the battery 11. Further, the first motor 13 may function as a starter that starts the internal combustion engine 12. That is, the first motor 13 can be a drive source, a generator, or a starter of the vehicle 10 according to the operating state. The first motor 13 is provided with a power measurement device 131.

[0022] The power measurement device 131 detects, as a power generation index indicating the generated power of the first motor 13, for example, fluctuations in current value, voltage value, power value, and torque. For example, the power measurement device 131 includes various measurement devices and sensors such as an ammeter that measures the current value, a voltmeter that measures the voltage value, a power sensor that measures the power value, or a torque sensor that detects the torque applied to a drive shaft such as a drive shaft or a propeller shaft.

[0023] The inverter is provided between the battery 11 and the first motor 13 and between the battery 11 and the second motor 15, and includes power elements, capacitors, a control circuit, etc. The inverter converts the DC voltage from the battery 11 into an AC voltage and supplies a three-phase current to the motors 13 and 15. Further, the inverter converts the AC voltage generated by the motor 13 into a DC voltage.

[0024] The clutch 14 is, for example, a dry friction clutch provided on the output side of the internal combustion engine 12. The clutch 14 is configured to be able to disconnect and connect the power transmission path from the internal combustion engine 12 to the traveling unit 16 under the control of the control unit 17.

[0025] The second motor 15 includes a motor case, a stator fixed to the motor case, and a rotor fixed to a shaft pivotally supported by the motor case. The second motor 15 is connected to the traveling unit 16. Further, the second motor 15 is connected to the battery 11 via an inverter. The second motor 15 functions as a drive motor that rotates the shaft of the traveling unit 16 when power is supplied from the battery 11. That is, the second motor 15 serves as a drive source of the vehicle 10.

[0026] The running gear 16 includes a drive shaft, an automatic transmission, a power transmission device, front wheels, and rear wheels, etc. For example, an automatic transmission is disconnectably connected to the output shaft of the internal combustion engine 12 via a clutch 14, and the left and right front wheels and rear wheels, which are drive wheels, are connected to the output shaft of the automatic transmission via a power transmission device including a propeller shaft, a differential gear, a transfer, etc. The running gear 16 shifts the power generated by the rotation of the internal combustion engine 12 transmitted via the clutch 14 at a predetermined gear ratio by the automatic transmission and transmits it to the front wheels and rear wheels via the power transmission device.

[0027] The control unit 17 is a device that performs operations such as a computer, and includes various processing circuits such as an input / output device, a storage device (ROM, RAM, non-volatile RAM, etc.), and a central processing unit (CPU). By executing various programs, the control unit 17 functions as a running control device and a vehicle state detection device (fault diagnosis device). The control unit 17 may be provided in the vehicle 10, or part or all of it may be provided in another external terminal. For example, the control unit 17 serving as a vehicle state detection device may be part of the ECU that controls the internal combustion engine 12. Also, the control unit 17 serving as a vehicle state detection device (vehicle state detection unit) may be provided in a terminal separate from the vehicle 10.

[0028] A crank angle sensor 121, a power measurement device 131, and other various sensors are connected to the control unit 17, and detection and operation information from these devices are input. Also, the control unit 17 is connected to the internal combustion engine 12, the first motor 13, the clutch 14, and the second motor 15, and controls the operations of these components.

[0029] For example, the control unit 17 controls the driving of the vehicle 10 based on operation information such as the accelerator operation information of the vehicle 10 and various detection values. That is, the control unit 17 transmits control signals to each part to perform control processes necessary for various operations, such as output control of the motors 13 and 15, control of the power generation amount of the first motor 13, switching control of the clutch 14, and operation control of the internal combustion engine 12. For example, the control unit 17 controls the torque and rotational speed generated by the internal combustion engine 12 by controlling the fuel injection amount of the internal combustion engine 12. Further, the control unit 17 switches the connection state of the drive source and switches the driving mode by controlling the engagement and disengagement of the clutch 14. Also, the control unit 17 controls the outputs of the motors 13 and 15.

[0030] For example, the control unit 17 drives the vehicle 10 in a plurality of different driving modes in which a plurality of drive sources of the first motor 13, the second motor 15, and the internal combustion engine 12 are appropriately combined according to the driving state. For example, in addition to the first driving mode using the second motor 15 as the drive source, a driving mode using both the first motor 13 and the second motor 15 as the drive source, a driving mode using either or both of the first motor 13 and the second motor 15 and the internal combustion engine 12 as the drive source, a driving mode using only the internal combustion engine 12 as the drive source, etc., a plurality of different driving modes are switched according to the driving state to control the vehicle 10.

[0031] Hereinafter, the vehicle state detection method (fault diagnosis method) according to the present embodiment will be described with reference to the flowchart of FIG. 3. The vehicle state detection method according to the present embodiment includes acquiring a power generation index indicating the power generation power generated by the first motor 13, and comparing the transition of the acquired current power generation index with the transition of the reference power generation index to detect the state of the internal combustion engine 12.

[0032] In this embodiment, as an example, in the case of a first driving mode in which the second motor 15 is driven by the power supplied from the battery 11 to drive the traveling unit 16 to drive the vehicle 10, a failure diagnosis process is performed, and an example of detecting the presence or absence of an abnormality as the state of the internal combustion engine 12 is shown. For example, in the first driving mode, the clutch 14 is disengaged, and the driving force required for traveling is output from the second motor 15. That is, the vehicle 10 is caused to travel by driving the second motor 15 with the power supplied from the battery 11 to drive the traveling unit 16.

[0033] First, as ST1, the control unit 17 determines whether or not the start condition of the failure diagnosis process is satisfied. For example, in this embodiment, when the clutch 14 of the first motor 13 is disengaged and the vehicle is traveling electrically by the second motor 15, it is determined that the start condition is satisfied. When the control unit 17 determines that the start condition is satisfied (Yes in ST1), the process proceeds to ST2. When the control unit 17 determines that the start condition is not satisfied (No in ST1), the estimation process ends.

[0034] In ST2, the control unit 17 operates the internal combustion engine 12 at a constant rotational speed, absorbs torque by the first motor 13 to generate electricity, and measures the generated power. Then, the control unit 17 obtains the transition of the current power generation power index of the first motor 13. For example, the transition is a time transition. For example, at this time, the rotational speed of the internal combustion engine 12 is set to be constant, the generated power is supplied to the battery 11, and the battery 11 is charged. In ST2, the control unit 17 uses various sensors or measuring instruments attached to the first motor 13 or the wiring system or the like to obtain a power generation waveform W1, which is a transition of a power generation index including at least any one of current, voltage, power, and torque, as information regarding the generated power. The power generation waveform W1 is, for example, a voltage value, a current value, a power value, or a torque value with time as the horizontal axis, and exhibits a waveform that repeats at a predetermined period, as shown in FIG. 4, for example. For example, the control unit 17 can confirm the torque fluctuation in the steady state by detecting the output torque when the engine is operated with a constant rotational speed. The process proceeds to ST3.

[0035] In ST3, the control unit 17 acquires the reference power generation waveform W2. Assume that the reference power generation waveform W2 is the transition of the power generation index of the first motor 13 measured in the past. For example, the transition is a time transition. The reference power generation waveform W2 is the transition of the power generation index measured when the internal combustion engine 12 is in a normal state at the time of shipment or at a predetermined timing before ST2. Assume that the data indicating the reference power generation waveform W2 is stored in the storage device of the control unit 17. The process proceeds to ST4. In ST4, the control unit 17 compares the power generation waveform W1 with the reference power generation waveform W2 to determine whether there is an abnormality in the internal combustion engine 12.

[0036] FIG. 4 shows the power generation waveform W1, which is the transition of the power (current × voltage) obtained as the detection result of the power measurement device 131, by a broken line, and the reference power generation waveform W2, which is the transition of the power (current × voltage) measured by the power measurement device 131 in the past, by a solid line. In FIG. 4, the crank angle waveform W3 is shown in synchronization with the power generation waveform W1 and the reference power generation waveform W2. In the present embodiment, the internal combustion engine 12 is a four-cylinder engine, and both the power generation waveform W1 and the reference power generation waveform W2 have a shape in which a mountain-shaped waveform is repeated, for example, every 180°.

[0037] Here, as shown in FIG. 4, it can be seen that the shape and numerical value of the power generation waveform W1 change in the part of the third mountain-shaped waveform. In FIG. 4, other parts overlap with the reference power generation waveform W2 shown by a solid line and have the same shape. For example, when the difference in shape and numerical value between the power generation waveform W1 and the reference power generation waveform W2 is equal to or greater than a predetermined value or within a predetermined range, the control unit 17 determines that there is an abnormality in the internal combustion engine 12 (ST4 Yes). On the other hand, when the difference in shape and numerical value between the power generation waveform W1 and the reference power generation waveform W2 is less than a predetermined value or within a predetermined range, it is determined that there is no abnormality (ST4 No), and the estimation process ends. At this time, for example, the maximum value of the difference in numerical values of the two waveforms W1 and W2 may be used for determination, or determination may be made based on the average value. In addition, determination may be made based on the difference in the shape of the waveform, including deviation and inclination.

[0038] In ST5, the control unit 17 detects the crank angle. In ST6, the control unit 17 synchronizes and superimposes the measured power generation waveform W1 of the first motor 13 and the crank angle waveform W3. In ST7, the control unit 17 identifies the cylinder with a problem based on the crank angle waveform W3 that overlaps with the waveform determined to be abnormal in ST4 among the power generation waveforms W1.

[0039] For example, in the example shown in FIG. 4, in the measured power generation waveform W1, it can be seen that the part presenting a waveform different from the reference power generation waveform W2 corresponds to the time point when the crank angle is between 360° and 540°. Therefore, by identifying the crank angle corresponding to the part presenting the abnormal value, the cylinder showing the abnormal value can be identified.

[0040] Note that when the control unit 17 determines in ST4 that there is an abnormality in the internal combustion engine 12, it may perform an operation during a failure, such as prompting the user for maintenance through a notification process or restricting the use of the vehicle 10 by restricting the operation of the internal combustion engine 12.

[0041] According to the vehicle 10 according to the present embodiment, by comparing the characteristics of the generated power generated by the first motor 13 with the characteristics of the generated power in the past, it is possible to estimate the problem that has occurred in the combustion chamber of the internal combustion engine 12. Therefore, it is possible to easily detect the problem of the internal combustion engine 12 by using the measuring instruments and sensors normally provided in the vehicle 10. Further, by synchronizing and corresponding the waveform of the power generation index with the crank angle waveform measured by the crank angle sensor 121 of the internal combustion engine 12, it is possible to estimate the cylinder in which the problem has occurred. Further, according to the above embodiment, with the clutch 14 disengaged, the index of the generated power when the engine speed is constant is detected, and as the variation of the power generation index when the engine is operated in a steady state, for example, the torque variation can be confirmed. For this reason, the torque of only the engine can be detected, and the accuracy of the failure diagnosis can be improved.

[0042] Note that the present invention is not limited to the above embodiment. For example, various sensors and measuring instruments, which are detection units for measuring indicators of generated power, may be directly mounted on the motor 13, or may be provided in a wiring system such as a high-voltage wiring.

[0043] Also, the driving mode of the vehicle 10 is not limited to those exemplified in the above embodiment, and may be a series type or a parallel type. Further, for example, the vehicle 10 may be configured to supply the electricity obtained by the regenerative brake to the battery 11.

[0044] For example, in the above embodiment, the disconnection of the clutch 14 and the start of EV driving by the second motor 15 are shown as an example of the start condition, but it is not limited thereto. For example, the detection timing can be set as appropriate, such as periodically or when the internal combustion engine 12 is operating. For example, measurement or failure diagnosis processing may be performed not only during running but also during stopping. Therefore, for example, if the driving force of the driving wheels of the running unit 16 can be accurately detected at any time, data can be synchronized in real time, and torque fluctuations under various driving conditions can be recorded, it is possible to perform failure diagnosis even with the clutch connected.

[0045] Also, the operation after failure diagnosis is not limited to the above notification processing. For example, after failure diagnosis, in addition to or instead of the notification processing, the internal combustion engine 12 may be stopped, or may be driven to a predetermined output and then stopped, and the operation of the internal combustion engine 12 may be restricted, such as suppressing the fuel injection amount. Also, the criteria for determination are not limited to numerical values or ranges indicating failures. Further, for example, threshold values may be set in multiple stages, and predictive diagnosis may be performed using numerical values or ranges that may indicate failures before a failure as criteria for determination to prompt the user for maintenance.

[0046] Also, the reference power generation index is based on past data, but it may be data obtained when the internal combustion engine 12 was operated at a certain timing immediately before, or the reference power generation index may be obtained by operating the engine alone at the time of shipment.

[0047] The vehicle 10 is configured to switch the connection state by the clutch 14, but it is not limited thereto.

[0048] In the above embodiment, an example in which the internal combustion engine 12 and each of the motors 13 and 15 are provided one by one has been shown, but the present invention is not limited to this, and it may be driven in a plurality of systems. Also, various driving methods such as front-wheel drive, rear-wheel drive, and four-wheel drive can be applied to the driving method.

[0049] Also, in the above embodiment, an example in which the control unit 17, which is a vehicle state detection device, is mounted on the vehicle 10 has been shown, but the present invention is not limited to this. For example, it may be a terminal that can be retrofitted to the vehicle 10, or it may be provided in an external terminal. Further, for example, using data such as a power generation index detected in the vehicle 10, it may be transmitted to a terminal other than the vehicle 10 by wired or wireless communication, and a determination process may be performed from the external terminal during maintenance or the like. For example, a determination process can be performed on an external terminal using an app or the like of a smartphone or the like.

[0050] As described above, one embodiment of the present invention has been described in detail. However, the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. can be made as appropriate. The present invention is defined by the scope of the claims, and includes all changes within the meaning and scope equivalent to the scope of the claims.

Explanation of Signs

[0051] 10... Vehicle, 11... Battery, 12... Internal combustion engine, 12a - 12d... Cylinders, 13... Motor, 14... Clutch, 15... Motor, 16... Running part, 17... Control unit, 121... Crank angle sensor, 131... Power measurement device, W1... Measured power generation waveform, W2... Reference power generation waveform, W3... Crank angle waveform.

Claims

1. In a hybrid vehicle including an internal combustion engine and a first motor that generates electricity by the internal combustion engine, a state of the internal combustion engine is detected based on a power generation index indicating power generation power generated by the first motor. A vehicle state detection device for a hybrid vehicle.

2. The vehicle state detection device according to claim 1, wherein a defect of the internal combustion engine is detected based on a time change of the power generation index and a time change of a reference power generation index.

3. The vehicle state detection device for a hybrid vehicle according to claim 1, wherein information on a cylinder having an abnormality in the internal combustion engine is detected based on a time change of the power generation index and a time change of a crank angle of the internal combustion engine.

4. The vehicle state detection device for a hybrid vehicle according to claim 1, wherein the power generation index includes at least any one of information on a voltage value, a current value, a power value, and a torque.

5. An internal combustion engine, A first motor connected to the internal combustion engine, A detection unit that operates the internal combustion engine and detects a power generation index indicating power generation power generated by the first motor, A vehicle state detection unit that detects a state of the internal combustion engine based on the power generation index, A hybrid vehicle comprising:

6. The hybrid vehicle according to claim 5, wherein the vehicle state detection unit detects a defect of the internal combustion engine based on a time change of the power generation index and a time change of a reference power generation index.

7. A battery connected to the first motor, A second motor connected to the battery, A traveling unit, A switching device that switches a connection state between the first motor and the traveling unit, When the connection between the first motor and the traveling unit is disconnected, an internal combustion engine is operated at a predetermined rotational speed, the first motor is caused to generate electricity, and a power generation index is detected, a control unit, a hybrid vehicle according to claim 5, comprising.

8. The switching device has a clutch, a hybrid vehicle according to claim 7.

9. Based on the power generation index and a reference power generation index as a reference, a control unit that performs notification processing or operation restriction of the internal combustion engine, a hybrid vehicle according to claim 6.

10. The control unit detects information on a cylinder having an abnormality based on the waveform of the power generation index and the waveform of the crank angle of the internal combustion engine, a hybrid vehicle according to claim 9.

11. In a hybrid vehicle including an internal combustion engine and a first motor that generates electricity by the internal combustion engine, Detecting a power generation index indicating the generated power generated by the first motor; Detecting the state of the internal combustion engine based on the power generation index; A vehicle state detection method for a hybrid vehicle, comprising.

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