Hybrid vehicle and method for controlling hybrid vehicle

Abstract

The invention provides a hybrid vehicle and a control method of the hybrid vehicle. The hybrid vehicle and the control method of the hybrid vehicle can suppress increase of calculation amount, prevent surge and maintain operation performance. This hybrid vehicle is provided with: a first determination unit that determines the surge state of a turbocharger on the basis of the state of an engine; a second determination unit that determines the surge state of the turbocharger on the basis of the state of the turbocharger; and a control unit that controls the engine and the assist of the electric drive motor to the engine on the basis of the determination results of the first determination unit and the second determination unit.

Description

Technical Field

[0001] The present invention relates to a hybrid vehicle and a control method of the hybrid vehicle. Background Art

[0002] Conventionally, for example, there is a hybrid vehicle including an engine, a turbocharger, and an electric drive motor as described in Patent Document 1. Patent Document 1 describes a technique in which the engine is controlled in such a manner that a turbo surge phenomenon generated in a compressor of a turbocharger can be avoided, and the driving force of the electric drive motor is used to compensate for the reduction in the driving force of the engine at this time. According to the technique of Patent Document 1, a hybrid vehicle can be realized that can avoid the turbo surge phenomenon of the turbocharger while maintaining the driving performance.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-182725. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, in the hybrid vehicle described in Patent Document 1, the occurrence of turbine surging (hereinafter sometimes referred to as "surge") is predicted based on the engine speed, upshifting of the transmission, and the vehicle speed, and the engine and the electric drive motor are controlled.

[0008] Therefore, in the hybrid vehicle described in Patent Document 1, there is a possibility that surge cannot be predicted when applied to a vehicle using a continuously variable transmission, etc. In addition, in the hybrid vehicle described in Patent Document 1, there is a possibility that surge occurs when the accelerator is suddenly turned off.

[0009] Furthermore, in the conventional configuration, in order to reliably prevent surging, the amount of calculation increases and the control becomes complicated.

[0010] The present invention has been made in consideration of the above points, and provides a hybrid vehicle and a control method for a hybrid vehicle that can suppress an increase in the amount of calculation and prevent the occurrence of surging while maintaining the driving performance.

[0011] Solutions to the problem

[0012] One aspect of the hybrid vehicle of the present invention comprises:

[0013] engine;

[0014] A turbocharger connected to an air supply and exhaust system of the engine;

[0015] Electric drive motor;

[0016] a first determination unit that determines a surge state of the turbocharger based on a state of the engine;

[0017] a second determination unit that determines a surge state of the turbocharger based on a state of the turbocharger; and

[0018] The control unit controls the engine and the assist of the engine by the electric drive motor based on the determination results of the first determination unit and the second determination unit.

[0019] One aspect of a hybrid vehicle control method of the present invention is a hybrid vehicle control method having an engine, an electric drive motor, and a turbocharger connected to an air supply and exhaust system of the engine, comprising:

[0020] A first determination step is to determine a surge state of the turbocharger based on a state of the engine;

[0021] A second determination step of determining a surge state of the turbocharger based on the state of the turbocharger; and

[0022] The control step controls the engine and the assist of the engine by the electric drive motor based on the determination results of the first determination step and the second determination step.

[0023] Effects of the Invention

[0024] According to the present invention, a hybrid vehicle and a control method of a hybrid vehicle can be realized, which can prevent the occurrence of surging while suppressing an increase in the amount of calculation and maintaining the driving performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram showing a main structure of a hybrid vehicle according to an embodiment.

[0026] Figure 2 It is a flowchart for explaining the operation of the embodiment.

[0027] Figure 3 1 is a diagram for explaining the determination process of the first determination unit, and shows the relationship between the engine speed, the fuel flow rate, and the state near the surging region.

[0028] Figure 4This is a diagram showing the relationship between the corrected air flow rate, the pressure ratio between the compressor inlet pressure and the outlet pressure, and a region corresponding to the vicinity of the surge region, for explaining the determination process of the first determination unit.

[0029] Figure 5 This is a diagram for explaining the difference between the vehicle required torque and the engine actual torque.

[0030] Figure 6 It is a diagram showing an example of the motor speed and output torque of the electric drive motor.

[0031] Description of Reference Numerals

[0032] 1 Hybrid vehicles

[0033] 10 Engine

[0034] 20 Turbocharger

[0035] 21 Turbine

[0036] 22 Compressor

[0037] 30 Power transmission mechanism

[0038] 40 Electric drive motor

[0039] 60 Control Unit

[0040] 61 Control Department

[0041] 62 First Judgment Unit

[0042] 63 Second Judgment Section

[0043] 71 Engine rotation sensor

[0044] 72 Fuel sensor

[0045] 73 Accelerator sensor

[0046] 74a, 74b pressure sensor

[0047] 75 Turbine rotation sensor

[0048] 76 Flow sensor DETAILED DESCRIPTION

[0049] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0050] Figure 11 is a schematic diagram showing the main structure of a hybrid vehicle 1 according to an embodiment. The hybrid vehicle 1 includes: an internal combustion engine (diesel engine or gasoline engine, etc., hereinafter referred to as "engine") 10; a turbocharger 20 connected to the air supply and exhaust system of the engine 10; a power transmission mechanism 30 that transmits the driving torque generated by the engine 10; an electric drive motor 40 connected to the power transmission mechanism 30; and a battery 42 that is electrically connected to the electric drive motor 40 via an inverter 41.

[0051] The engine 10 includes an engine body 11, an exhaust manifold 12, an intake manifold 13, etc. Exhaust gas generated in the engine body 11 is sent to the turbocharger 20 via the exhaust manifold 12, drives the turbine 21 of the turbocharger 20, and is then purified by the exhaust gas treatment device 51 and discharged.

[0052] Intake air sucked from the air cleaner 52 is compressed and cooled by the compressor 22 of the turbocharger 20 and the intake air cooler 53 , and is regulated by the intake throttle valve 54 before being supplied to the engine body 11 via the intake manifold 13 .

[0053] The power transmission mechanism 30 transmits the driving torque generated by the engine 10 to the transmission (gearbox) 33 via the torque converter 31 and the friction clutch (for example, a wet clutch using a viscous coupling) 32. Next, the driving torque is transmitted from the transmission 33 to the drive wheels 55 via the propeller shaft 34, the differential 35, and the drive shaft 36. It should be noted that the structure of the power transmission mechanism is not limited to this. The power transmission mechanism may also be, for example, a CVT (Continuously Variable Transmission) or a DCT (Dual Clutch Transmission).

[0054] In addition, the driving torque generated by the electric drive motor 40 is transmitted to the drive wheel 55 via the driven dog clutch (hereinafter referred to as "dog clutch") 37a of the PTO (power input and output mechanism) 37. It should be noted that the present invention is not limited to a hybrid vehicle in which the driving torque generated by the electric drive motor 40 is transmitted to the drive wheel 55 via the PTO 37, but can be widely applied to known hybrid vehicles that perform drive assistance and regeneration based on the electric drive motor 40.

[0055] The electric drive motor 40 acts as a generator to impart braking force to the power transmission mechanism 30 to perform regenerative power generation during regenerative drive, and acts as a motor to impart driving force to the power transmission mechanism 30 to assist during electric rotation drive. It should be noted that the generated power is converted by the inverter 41 and then charged into the battery 42. In addition, when the electric drive motor 40 is electrically driven, the power charged into the battery 42 is converted by the inverter 41 and then supplied to the electric drive motor 40.

[0056] Furthermore, the hybrid vehicle 1 has a control unit 60. The control unit 60 has a control unit 61, a first determination unit 62, and a second determination unit 63. The control unit 61, the first determination unit 62, and the second determination unit 63 each have a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like as main components. The CPU reads a program corresponding to the processing content from the ROM and expands it in the RAM, and cooperates with the expanded program to realize the functions of the control unit 61, the first determination unit 62, and the second determination unit 63. It should be noted that all or part of the control unit 61, the first determination unit 62, and the second determination unit 63 may also be formed by a hard-wired circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0057] The first determination unit 62 receives the engine speed from the engine rotation sensor 71, the fuel flow rate from the fuel sensor 72, and the accelerator opening from the accelerator sensor 73. The first determination unit 62 determines the surging state of the turbocharger 20 based on the engine speed and one of the fuel flow rate and the accelerator opening.

[0058] It should be noted that the "surge state" in this specification is not limited to the state where surge is occurring, but includes the state close to the state where surge is occurring and the state facing the state where surge is occurring. In other words, the "surge state" can also be understood as "the state close to surge" or "the state related to the induction of surge".

[0059] The second determination unit 63 is input with pressure values ​​from pressure sensors 74a and 74b provided at the inlet and outlet of the compressor 22 of the turbocharger 20, the turbine speed from the turbine rotation sensor 75, and the compressor intake air amount from the flow sensor (MAF (Mass Flow) sensor) 76. The second determination unit 63 determines the surging state of the turbocharger based on the pressure difference (or pressure ratio) at the outlet and inlet of the compressor 22 of the turbocharger 20, the speed of the turbine 21, and the intake air amount of the compressor 22.

[0060] The control unit 61 controls the engine 10 and the assist of the engine 10 by the electric drive motor 40 based on the determination results of the first determination unit 62 and the second determination unit 63. Specifically, when the control unit 61 obtains the determination result that the turbocharger 20 is in the vicinity of the surging state through the first determination unit 62 and the second determination unit 63, the control unit 61 performs the following control, that is, suppressing the speed and fuel flow of the engine 10 and causing the electric drive motor 40 to assist the control of the engine 10. It should be noted that, although not shown in the figure, vehicle state information such as vehicle speed, vehicle weight, and gear position is actually input to the control unit 61. In addition to the determination results of the first determination unit 62 and the second determination unit 63, the control unit 61 also considers these vehicle state information to suppress the speed and fuel flow of the engine 10 and cause the electric drive motor 40 to assist the control of the engine 10.

[0061] Figure 2 This is a flowchart for explaining the operation of the hybrid vehicle 1 according to the present embodiment.

[0062] The hybrid vehicle 1 waits for the ignition switch to be turned on in step S11 , and if the ignition switch is turned on (step S11 : YES), the process proceeds to step S12 .

[0063] In step S12, the first determination unit 62 reads the engine speed (Ne), the fuel flow rate (Q), and the accelerator opening (APS). In the next step S13, the first determination unit 62 determines whether the operating state of the engine 10 is a state close to the surge region of the turbocharger 20. Specifically, the first determination unit 62 determines whether the relationship between the engine speed and the fuel flow rate (or the accelerator opening (also referred to as the engine torque)) (that is, the operating point of the engine 10) is in a state close to the surge region of the turbocharger 20. Figure 3 If the operating state of the engine 10 is in the region A indicated by the oblique lines, it is determined that the operating state of the engine 10 is in a state corresponding to the vicinity of the surge region of the turbocharger 20 (step S13: Yes), and the process proceeds to step S14.

[0064] In step S14, the second determination unit 63 reads the compressor inlet pressure and outlet pressure, turbine speed, and intake air volume (MAF value). In the next step S15, the second determination unit 63 determines whether the operating state of the compressor 22 of the turbocharger 20 is near the surge region. Specifically, the second determination unit 63 calculates the corrected air flow rate based on the turbine speed of the compressor 22 and the intake air volume of the compressor 22. When the relationship between the corrected air flow rate and the pressure ratio of the compressor inlet pressure and outlet pressure (that is, the operating point of the compressor 22) is in the surge region, the second determination unit 63 calculates the corrected air flow rate based on the turbine speed of the compressor 22 and the intake air volume of the compressor 22. Figure 4 In the case of area B indicated by the grid pattern, it is determined that the operating state of the compressor 22 is a state corresponding to the vicinity of the surge region (step S15: Yes), and the process proceeds to step S16.

[0065] It should be noted that the determination in step S15 uses Figure 4 However, since the compressor characteristic map is temperature-dependent, it is preferable to prepare a plurality of compressor characteristic maps corresponding to the temperature in advance and use the compressor characteristic map corresponding to the intake air temperature of the compressor 22 to perform the determination in step S15.

[0066] In step S16, the control unit 61 monitors vehicle conditions such as vehicle speed, vehicle weight, gear position, etc. In step S17, the control unit 61 controls the engine 10 in such a manner as to maintain the engine speed and fuel flow rate (engine side operation control). In other words, the control unit 61 suppresses the engine 10 speed and fuel flow rate.

[0067] In step S18, the control unit 61 calculates the difference between the vehicle required torque and the actual engine torque. The vehicle required torque refers to the torque required for vehicle performance, which is calculated by taking into account the vehicle weight, etc. in addition to the accelerator opening. The actual engine torque refers to the engine torque after the speed and fuel flow rate of the engine 10 are suppressed in step S17 to prevent surge. The control unit 61 calculates the difference between the vehicle required torque and the actual engine torque caused by the suppression of the speed and fuel flow rate of the engine 10 in step S17 to prevent surge. Figure 5 is a diagram showing this situation.

[0068] In the next step S19, the control unit 61 controls the electric drive motor 40 to assist the control of the engine 10. Specifically, the control unit 61 controls the electric drive motor 40 to output a torque equivalent to the difference calculated in step S18, thereby compensating the reduction in engine torque that has been suppressed to avoid surging with the output torque of the electric drive motor 40. It should be noted that Figure 6 An example of the motor speed and output torque of the electric drive motor 40 is shown.

[0069] The hybrid vehicle 1 ends the process when it is determined in the next step S20 that the ignition switch is off (step S20: YES), and returns to step S12 to repeat the above process when it is determined that the ignition switch is not off (step S20: NO).

[0070] As described above, according to the present embodiment, the hybrid vehicle 1 comprises: a first determination unit 62 for determining the surge state of the turbocharger 20 based on the state of the engine 10; a second determination unit 63 for determining the surge state of the turbocharger 20 based on the state of the turbocharger 20; and a control unit 61 for controlling the engine 10 and the assistance provided by the electric drive motor 40 to the engine 10 based on the determination results of the first determination unit 62 and the second determination unit 63.

[0071] As a result, it is possible to realize the hybrid vehicle 1 that can prevent the occurrence of surging while suppressing an increase in the amount of calculation and maintaining the driving performance.

[0072] Here, in the embodiment, the first determination unit 62 performs the determination process of the surge state using the parameters of the engine 10, and when the first determination unit 62 obtains a determination result close to the surge state, the second determination unit 63 performs the determination process of the surge state using the parameters of the turbocharger 20. In other words, it can be said that after the range of the surge state is narrowed by the rough determination by the first determination unit 62, the second determination unit 63 performs a detailed determination of the surge state.

[0073] The determination of the second determination unit 63 includes the following processing, that is, the processing of calculating the corrected air flow rate based on the turbine speed of the compressor 22 and the intake air amount of the compressor 22. Therefore, if Figure 4 If all the operating points of the compressor characteristic line diagram shown in the figure are used as processing objects, the amount of calculation will become very large. In contrast, the determination of the first determination unit 62 can be easily performed based on the relationship between the engine speed and the fuel flow rate (or the accelerator opening), so it can be realized with a small amount of calculation.

[0074] In this embodiment, considering this point, first, the first determination unit 62 roughly determines whether the state is close to the surging state. On this basis, if the first determination unit 62 determines that the state is close to the surging state, the second determination unit 63 determines in detail whether the state is close to the surging state. In particular, Figure 4 It can also be seen that on the low speed and high load side, the operating point is close to the surge line, so it is necessary to perform control in this area in detail. In this embodiment, the first determination unit 62 can narrow the area where the second determination unit 63 performs determination processing to the vicinity of the surge line, and the second determination unit 63 can perform detailed determination near the surge line.

[0075] Thus, it is possible to reliably determine whether the state is close to surging with a small amount of calculation. Furthermore, when the second determination unit 63 determines that the state is close to surging, the control unit 61 controls the electric drive motor 40 in a manner that compensates for the reduction in engine torque while suppressing the engine drive. As a result, it is possible to realize a hybrid vehicle 1 that can suppress an increase in the amount of calculation and prevent the occurrence of surging while maintaining the driving performance.

[0076] The above-mentioned embodiments are only examples of specific implementations of the present invention, and the technical scope of the present invention should not be interpreted in a restrictive manner based on these. That is, the present invention can be implemented in various forms within the scope of the gist or main features of the present invention.

[0077] Industrial Applicability

[0078] The present invention can be applied to a hybrid vehicle including an engine, a turbocharger, and an electric drive motor.

Claims

1. A hybrid vehicle, characterized in that: have: engine; A turbocharger connected to an air supply and exhaust system of the engine; Electric drive motor; a first determination unit that determines a surge state of the turbocharger based on a state of the engine; a second determination unit, determining a surge state of the turbocharger based on a state of the turbocharger; as well as The control unit controls the engine and the assist of the engine by the electric drive motor based on the determination results of the first determination unit and the second determination unit.

2. The hybrid vehicle according to claim 1, wherein: The first determination unit determines a surging state of the turbocharger based on an engine speed and one of a fuel flow rate and an accelerator opening.

3. The hybrid vehicle according to claim 1, wherein: The second determination unit determines a surging state of the turbocharger based on pressures at an outlet and an inlet of a compressor of the turbocharger, a rotation speed of a turbine, and an intake air amount of the compressor.

4. The hybrid vehicle according to claim 1, wherein: When the first determination unit and the second determination unit obtain a determination result that the turbocharger is in the vicinity of a surging state, the control unit suppresses the rotation speed and the fuel flow rate of the engine and causes the electric drive motor to assist the engine.

5. The hybrid vehicle according to claim 4, wherein: The control unit calculates a difference between a required torque and an engine torque obtained by suppressing the engine speed and the fuel flow rate, and controls the electric drive motor so as to output a torque corresponding to the difference.

6. The hybrid vehicle according to claim 1, wherein: When the first determination unit obtains a determination result that the turbocharger is in the vicinity of the surging state, the determination by the second determination unit is performed.

7. A control method for a hybrid vehicle, the hybrid vehicle having an engine, an electric drive motor, and a turbocharger connected to an air supply and exhaust system of the engine, the control method for the hybrid vehicle comprising: A first determination step is to determine a surge state of the turbocharger based on a state of the engine; A second determination step of determining a surge state of the turbocharger based on the state of the turbocharger; as well as The control step controls the engine and the assist of the engine by the electric drive motor based on the determination results of the first determination step and the second determination step.

8. The control method of a hybrid vehicle according to claim 7, wherein: When a determination result that the turbocharger is in the vicinity of a surging state is obtained in the first determination step, the second determination step is performed.

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