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

Abstract

Provided are a vehicle state detection device capable of detecting the state of an internal combustion engine, a vehicle, and a vehicle state detection method. A vehicle state detection device for a hybrid vehicle according to one embodiment detects the state of an internal combustion engine on the basis of a power generation index indicating the power generated by a first electric motor in a hybrid vehicle having the internal combustion engine and the first electric motor that generates power by the internal combustion engine.

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, a hybrid electric vehicle (HEV) that uses an internal combustion engine and an electric motor as drive sources is known. In the hybrid electric vehicle as described above, a technology has been developed in which the internal combustion engine drives the electric motor for power generation, and supplies electric power to the electric motor for driving that generates the driving force of the vehicle.

[0003] For example, the vehicle includes: an internal combustion engine; a first electric motor that serves as a generator; a second electric motor for driving; a clutch disposed between the first electric motor and the second electric motor; and a battery. The vehicle switches the connection state of the clutch, and thereby performs operation control through a plurality of different driving modes such as a driving mode based on the second electric motor and a driving mode that uses both the second electric motor and the internal combustion engine.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-280082

[0005] In the vehicle as described above, the following technology is required, that is, to detect a state change of the internal combustion engine such as abnormal combustion caused by a problem in the combustion chamber of each cylinder of the internal combustion engine. Summary of the Invention

[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.

[0007] A vehicle state detection device for a hybrid electric vehicle according to one embodiment detects the state of the internal combustion engine based on a power generation index indicating the power generation power generated by the first electric motor in a hybrid electric vehicle having an internal combustion engine and a first electric motor that generates electric power by the internal combustion engine.

[0008] A hybrid electric vehicle according to other embodiments includes: an internal combustion engine; a first electric motor connected to the internal combustion engine; a detection unit that detects a power generation index indicating the power generation power generated by the first electric motor when the internal combustion engine operates; 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 electric vehicle according to other embodiments includes the following steps in a hybrid electric vehicle having an internal combustion engine and a first electric motor that generates electric power by the internal combustion engine: detecting a power generation index indicating the power generation power generated by the first electric motor; and detecting the state of the internal combustion engine based on the power generation index.

[0010] Effect of the Invention

[0011] According to the present invention, a vehicle state detection device, a vehicle, and a vehicle state detection method capable of detecting the state of an internal combustion engine can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a block diagram showing a schematic structure of a vehicle according to an embodiment of the present invention.

[0013] Figure 2 is an explanatory diagram showing a schematic structure of the vehicle according to this embodiment.

[0014] Figure 3 is a flowchart of vehicle state detection processing according to this embodiment.

[0015] Figure 4 is a waveform diagram of generated power and crank angle, showing the waveforms of generated power and crank angle overlapped synchronously. In addition, in each figure, for the purpose of explanation, the structure is appropriately enlarged, reduced, or omitted. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Hereinafter, with respect to a vehicle 10 according to an embodiment of the present invention, reference will be made to Figures 1 to 4 for explanation. Figure 1 is a block diagram showing the structure of the vehicle 10. Figure 2 is an explanatory diagram showing a part of the structure of the vehicle 10. Figure 3 is a flowchart of vehicle state detection processing according to this embodiment. Figure 4 is a waveform diagram of generated power and crank angle, showing the waveform of generated power and the crank angle waveform overlapped synchronously. In addition, in each figure, for the purpose of explanation, the structure is appropriately enlarged, reduced, or omitted.

[0017] As Figure 1 and Figure 2 shown, the vehicle 10 is a hybrid electric vehicle (HEV) of a series-parallel type equipped with an internal combustion engine 12, a first motor 13, and a second motor 15 as drive sources.

[0018] The vehicle 10 is, for example, a truck.

[0019] 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 traveling unit 16, and a control unit 17.

[0020] The battery 11 is a power source of the vehicle 10. The battery 11 is connected to the first motor 13 and the second motor 15 via inverters, respectively. For example, as the battery 11, a lithium-ion battery, a solid-state lithium-ion battery, a graphene secondary battery, etc. are used. For example, the battery 11 has a battery module, and the battery module has a plurality of battery cells.

[0021] 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 type engine having a plurality of cylinders 12a to 12d. Each of the cylinders 12a to 12d is provided with 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 operates, thereby generating power (torque) that becomes a driving force. The opening and closing, the supply amount, and the timing of the fuel injection valves of the respective cylinders 12a to 12d of the internal combustion engine 12 are configured to be controllable by the control unit 17.

[0022] The internal combustion engine 12 is connected to the traveling unit 16 via the clutch 14 and drives the traveling unit 16. In addition, the internal combustion engine 12 is connected to the first electric motor 13 and drives the first electric motor 13 to generate electricity.

[0023] A crank angle sensor 121 for measuring the crank angle of the internal combustion engine 12 is provided in the internal combustion engine 12. The crank angle sensor 121 detects the reference position, the rotation angle, and the rotational speed of the crankshaft of the internal combustion engine 12 and outputs pulses as a crank angle signal for each prescribed crank angle. For example, an optical or electromagnetic sensor is used as the crank angle sensor 121. For example, the crank angle waveform W3 measured by the crank angle sensor 121 is as Figure 4 shown, a waveform having a pulse waveform every 180°. For example, the crank angle waveform W3 has one pulse waveform each in 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.

[0024] The first electric motor 13 has, for example: a motor housing; a stator fixed to the motor housing; and a rotor fixed to a shaft that is supported by the motor housing on the shaft. For example, the first electric motor 13 is connected to the battery 11 via an inverter.

[0025] The main shaft of the first electric motor 13 is connected to the internal combustion engine 12. The first electric motor 13 is configured to be able to generate electricity by the power of the internal combustion engine 12. That is, the first electric motor 13 inputs a rotational force from the internal combustion engine 12 to the main shaft, thereby acting as a generator. In addition, the first electric motor 13 charges the battery 11 with the electric power generated by generating electricity by absorbing the torque of the internal combustion engine 12.

[0026] The first electric motor 13 may also be supplied with electric power from the battery 11 and thereby act as a drive motor for driving the traveling unit 16. And the first electric motor 13 may also act as a starter for starting the internal combustion engine 12. That is, the first electric motor 13 can become a drive source, a generator, or a starter of the vehicle 10 according to the operating state.

[0027] A power measurement device 131 is provided in the first electric motor 13.

[0028] The power measurement device 131 detects, for example, changes in current value, voltage value, power value, and torque as an index indicating the generated power of the first motor 13, i.e., the generation index. For example, the power measurement device 131 includes various measurement devices and sensors such as an ammeter for measuring the current value, a voltmeter for measuring the voltage value, a power sensor for measuring the power value, or a torque sensor for detecting the torque applied to a drive shaft such as a drive shaft or a transmission shaft.

[0029] Inverters are respectively provided between the battery 11 and the first motor 13, and between the battery 11 and the second motor 15, and include power elements, capacitors, control circuits, etc. The inverter converts the DC voltage from the battery 11 into an AC voltage and supplies three-phase current to the motors 13 and 15. In addition, the inverter converts the AC voltage generated by the power generation of the motor 13 into a DC voltage.

[0030] 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 cut off / connect the power transmission path from the internal combustion engine 12 to the traveling unit 16 through the control of the control unit 17.

[0031] The second motor 15 includes: a motor housing; a stator fixed to the motor housing; and a rotor fixed to a shaft that is shaft-supported by the motor housing. The second motor 15 is connected to the traveling unit 16. In addition, the second motor 15 is connected to the battery 11 via an inverter. The second motor 15 is supplied with power from the battery 11 and thus functions as a drive motor that rotates the shaft of the traveling unit 16. That is, the second motor 15 becomes a drive source of the vehicle 10.

[0032] The traveling unit 16 includes a drive shaft, an automatic transmission, a power transmission device, front wheels, rear wheels, etc. For example, the automatic transmission is connected to the output shaft of the internal combustion engine 12 in a cut-off / connectable manner via the clutch 14, and the left and right front wheels and rear wheels as drive wheels are connected to the output shaft of the automatic transmission via a power transmission device having a transmission shaft, a differential gear, a transfer case, etc. The traveling unit 16 shifts the power generated by the rotation of the internal combustion engine 12 transmitted through the clutch 14 at a specified gear ratio through the automatic transmission and transmits it to the front wheels and rear wheels via the power transmission device.

[0033] The control unit 17 is a device for performing operations such as a computer, and has various processing circuits such as an input / output device, a storage device (ROM, RAM, non-volatile RAM, etc.), and a central processing unit (CPU). The control unit 17 executes various programs and thus functions as a driving control device and a vehicle state detection device (fault diagnosis device). The control unit 17 may be provided in the vehicle 10, or a part or all of it may be provided in other external terminals. For example, the control unit 17 that becomes a vehicle state detection device may be a part of the ECU that controls the internal combustion engine 12. In addition, the control unit 17 that becomes a vehicle state detection device (vehicle state detection unit) may be provided in a terminal different from the vehicle 10.

[0034] The crank angle sensor 121, the power measurement device 131, and various other sensors are connected to the control unit 17, and detection and operation information from these devices are input to the control unit 17. In addition, 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 respective parts.

[0035] For example, the control unit 17 performs drive control on the vehicle 10 based on operation information such as accelerator operation information of the vehicle 10 and various detection values. That is, the control unit 17 sends control signals to each part and performs various control processes required for operation, 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 fuel injection amount of the internal combustion engine 12, thereby controlling the torque and rotational speed generated by the internal combustion engine 12. In addition, the control unit 17 controls the disconnection / connection of the clutch 14, thereby switching the connection state of the drive source and switching the driving mode. In addition, the control unit 17 controls the output of the motors 13 and 15.

[0036] For example, the control unit 17 operates the vehicle 10 in different multiple driving modes appropriately combined with the multiple drive sources of the first motor 13, the second motor 15, and the internal combustion engine 12 according to the operating state. For example, in addition to the first driving mode in which the second motor 15 is used as the drive source, according to the operating state, the control unit 17 switches between multiple different driving modes such as a driving mode in which both the first motor 13 and the second motor 15 are used as the drive source, a driving mode in which either one or both of the first motor 13 and the second motor 15 and the internal combustion engine 12 are used as the drive source, and a driving mode in which only the internal combustion engine 12 is used as the drive source, to control the vehicle 10.

[0037] Next, regarding the vehicle state detection method (fault diagnosis method) according to the present embodiment, refer to Figure 3The flowchart will be described. The vehicle state detection method according to this embodiment has the following steps: obtaining a power generation index indicating the power generated by the first motor 13; and detecting the state of the internal combustion engine 12 by comparing the change in the currently obtained power generation index with the change in the reference power generation index.

[0038] In this embodiment, as an example, the following example is shown. That is, in the case of the first driving mode or the like in which the second motor 15 is driven by the power supplied from the battery 11 to drive the traveling unit 16 and the vehicle 10 travels, a failure diagnosis process is performed to detect whether there is an abnormality as the state of the internal combustion engine 12. 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 second motor 15 is driven by the power supplied from the battery 11 to drive the traveling unit 16, thereby causing the vehicle 10 to travel.

[0039] First, as ST1, the control unit 17 determines whether 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 in EV mode 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.

[0040] In ST2, the control unit 17 operates the internal combustion engine 12 at a constant speed, generates electricity by the first motor 13 absorbing torque, and measures the generated power. Moreover, the control unit 17 obtains the change in the current power generation power index of the first motor 13. For example, the change is a change over time. For example, at this time, the rotational speed of the internal combustion engine 12 is set to be constant, and the generated power is supplied to the battery 11 to charge the battery 11. In ST2, the control unit 17 uses various sensors or measuring devices installed in the first motor 13 or the wiring system or the like to obtain, as information related to the power generation power, the change in the power generation index including at least any one of current, voltage, power, and torque, that is, the power generation waveform W1. 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 for example, as Figure 4 shown, has a waveform that repeats at a specified period. For example, the control unit 17 detects the output torque when the engine is operating with a constant rotational speed, thereby being able to confirm the torque variation in the steady state. The process proceeds to ST3.

[0041] In ST3, the control unit 17 obtains the reference power generation waveform W2. The reference power generation waveform W2 is set as the change in the power generation index of the first motor 13 measured in the past. For example, the change is a change over time. The reference power generation waveform W2 is the change in the power generation index measured under the condition that the internal combustion engine 12 is normal at the time of factory shipment or at a specified timing before ST2. The data representing the reference power generation waveform W2 is stored in the storage device of the control unit 17. The process proceeds to ST4.

[0042] In ST4, the control unit 17 compares the power generation waveform W1 and the reference power generation waveform W2, and determines whether there is an abnormality in the internal combustion engine 12.

[0043] Figure 4 The change in the power (current × voltage), that is, the power generation waveform W1, obtained as the detection result of the power measurement device 131 is represented by a dotted line, and the change in the power (current × voltage), that is, the reference power generation waveform W2, measured by the power measurement device 131 in the past is represented by a solid line. In Figure 4 the crank angle waveform W3 represents the power generation waveform W1 and the reference power generation waveform W2 synchronously. In the present embodiment, the internal combustion engine 12 is a four-cylinder engine, and the power generation waveform W1 and the reference power generation waveform W2 both have a shape that repeats a mountain-shaped waveform every 180°, for example.

[0044] Here, as Figure 4 shown, it can be seen that the shape and value of the waveform of the power generation waveform W1 change at the part of the third mountain-shaped waveform. In addition, in Figure 4 other parts overlap with the reference power generation waveform W2 represented by a solid line and have the same shape. For example, when the difference in the shape and value between the power generation waveform W1 and the reference power generation waveform W2 is greater than or equal to a specified value or within a specified range, the control unit 17 determines that there is an abnormality in the internal combustion engine 12 (Yes in ST4). On the other hand, when the difference in the shape and value between the power generation waveform W1 and the reference power generation waveform W2 is less than the specified value or outside the specified range, it is determined that there is no abnormality (No in ST4), and the estimation process ends. At this time, for example, the maximum value of the difference in the values of the two waveforms W1 and W2 can be used for determination, or determination can also be based on the average value. In addition to this, deviation and inclination can also be included, and determination can be made based on the difference in the shape of the waveforms.

[0045] In ST5, the control unit 17 detects the crank angle. In ST6, the control unit 17 overlaps the measured power generation waveform W1 of the first motor 13 and the crank angle waveform W3 synchronously. In ST7, the control unit 17 determines the problematic cylinder based on the crank angle waveform W3 that overlaps with the waveform determined to have an abnormality in ST4 among the power generation waveforms W1.

[0046] For example, in Figure 4 In the example shown in FIG. Figure 4 , it can be seen that in the measurement of the power generation waveform W1, the crank angle of the portion having a waveform different from the reference power generation waveform W2 corresponds to a time point between 360° and 540°. Therefore, by determining the crank angle corresponding to the portion having an abnormal value, it is possible to determine the cylinder indicating the abnormal value.

[0047] In addition, when the control unit 17 determines in ST4 that there is an abnormality in the internal combustion engine 12, it can perform an operation at the time of 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.

[0048] 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 past generated power, it is possible to estimate the problems occurring in the combustion chamber of the internal combustion engine 12. Therefore, it is possible to easily detect the problems of the internal combustion engine 12 using the gauges and sensors that are usually provided in the vehicle 10. In addition, by synchronously 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. In addition, according to the above-described embodiment, in a state where the clutch 14 is disengaged, the index of the generated power when the engine speed is kept constant is detected, and as the change in the power generation index when the engine is operating in a stable state, for example, the torque change can be confirmed. Therefore, it is possible to detect only the torque of the engine and improve the accuracy of the fault diagnosis.

[0049] In addition, the present invention is not limited to the above-described embodiment.

[0050] For example, various sensors and gauges, which are detection units for measuring the index of the generated power, may be provided not only directly on the motor 13 but also in a wiring system such as a high-voltage wiring.

[0051] In addition, regarding the driving mode of the vehicle 10, it is not limited to the driving modes exemplified in the above-described embodiment, and may be a series type or a parallel type. In addition, for example, the vehicle 10 may be a type that supplies the electricity obtained by the regenerative brake to the battery 11.

[0052] For example, in the above-described embodiment, the case where the clutch 14 is disengaged and the EV travel is performed by the second motor 15 is shown as an example of a start condition, but it is not limited thereto. For example, the detection timing can be regular or when the internal combustion engine 12 is operating, etc., and can be set appropriately. For example, it is not limited to during travel, and measurement or failure diagnosis processing can also be performed during stop. Therefore, for example, if the driving force of the drive wheels of the traveling unit 16 can be accurately detected at any time, the data can be synchronized in real time, and the torque fluctuations under various operating conditions can be recorded, then even if the clutch is kept engaged, failure diagnosis can be performed.

[0053] In addition, the operation after failure diagnosis is not limited to the above-described notification process. For example, after failure diagnosis, based on or instead of the notification process, the internal combustion engine 12 can be stopped, or driven to a specified output and then stopped, or the operation of the internal combustion engine 12 can be restricted such as suppressing the fuel injection amount. In addition, the determination criterion is not limited to a numerical value or range indicating a failure. In addition, for example, the threshold can be set in multiple stages, or before a failure, a numerical value or range with a possibility of failure can be used as a determination criterion for predictive diagnosis to prompt the user for maintenance.

[0054] In addition, the reference power generation index is set to be past data, but for example, it can also be data obtained when the internal combustion engine 12 is operated at a timing just before, or the reference power generation index can be obtained by operating the engine unit alone at the time of factory shipment.

[0055] The vehicle 10 is configured to switch the connection state by the clutch 14, but it is not limited thereto.

[0056] In the above-described embodiment, an example in which each has one internal combustion engine 12 and each motor 13, 15 is shown, but it is not limited thereto, and multiple systems can also be used for driving. In addition, regarding the driving method, various driving methods such as front-wheel drive, rear-wheel drive, and four-wheel drive can also be applied.

[0057] In addition, in the above-described embodiment, an example in which the vehicle state detection device, i.e., the control unit 17, is mounted on the vehicle 10 is shown, but it is not limited thereto. For example, it can also be configured to be able to be retrofitted to the terminal of the vehicle 10, or can be provided in an external terminal. In addition, for example, data such as the power generation index detected in the vehicle 10 can be used, and through wired or wireless communication, it can be sent to a terminal other than the vehicle 10, and the determination process can be performed from the external terminal during maintenance, etc. For example, an application such as a smartphone can also be used, and the determination process can be performed through the external terminal.

[0058] 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 can be appropriately modified, improved, etc. In the present invention, it includes all changes within the scope of the content shown in the claims and equivalent to the claims.

[0059] Description of reference numerals

[0060] 10... vehicle, 11... battery, 12... internal combustion engine, 12a to 12d... cylinders, 13... electric motor, 14... clutch, 15... electric motor, 16... traveling unit, 17... control unit, 121... crankshaft angle sensor, 131... power measurement device, W1... measured power generation waveform, W2... reference power generation waveform, W3... crankshaft angle waveform.

Claims

1. A vehicle state detection device for a hybrid vehicle, which, in a hybrid vehicle having an internal combustion engine and a first electric motor that generates electric power through the internal combustion engine, detects the state of the internal combustion engine based on a power generation index indicating electric power generated by the first electric motor.

2. The vehicle state detection device according to claim 1, wherein: A problem in the internal combustion engine is detected based on the time transition of the power generation index and the time transition of the power generation index serving as a reference.

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

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

5. A hybrid vehicle comprising: internal combustion engine; a first electric motor connected to the internal combustion engine; a detection unit that detects a power generation index indicating power generated by the first electric motor when the internal combustion engine is operated; and A vehicle state detection unit detects a state of the internal combustion engine based on the power generation index.

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

7. The hybrid vehicle according to claim 5, wherein: have: a battery connected to the first motor; a second electric motor connected to the battery; Traveling part; a switching device for switching a connection state between the first electric motor and the travel unit; as well as A control unit operates the internal combustion engine at a predetermined rotation speed to cause the first electric motor to generate electric power, and detects the electric power generation index when the connection between the first electric motor and the travel unit is disconnected.

8. The hybrid vehicle according to claim 7, wherein: The shift device has a clutch.

9. The hybrid vehicle according to claim 6, wherein: A control unit is provided for performing a notification process or limiting the operation of the internal combustion engine based on the power generation index and a reference power generation index serving as a reference.

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

11. A method for detecting a vehicle state of a hybrid vehicle, comprising the following steps in a hybrid vehicle having an internal combustion engine and a first electric motor for generating electric power by the internal combustion engine: detecting a power generation index indicating power generated by the first electric motor; and Based on the power generation index, the state of the internal combustion engine is detected.

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