Hybrid vehicles

Abstract

To further properly execute an ISC control that has the number of revolutions of an engine as the number of idling revolutions without any breakdown.SOLUTION: In a hybrid vehicle that can run while switching a connection state among an engine, a first motor and a second motor between a series hybrid state and a parallel hybrid state, when the connection state among the engine, the first motor and the second motor is set to be in the parallel hybrid state, an idle speed control that has the number of revolutions of the engine as the predefined number of idle revolutions, and a learning in the idle speed control are prohibited.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle that can be run by switching between a series hybrid state and a parallel hybrid state. [Background technology]

[0002] Conventionally, for this type of hybrid vehicle, when the engine is controlled to an idle state, a system has been proposed in which the throttle opening is feedback-controlled by idle speed control (ISC control) (see, for example, Patent Document 1). In this hybrid vehicle, when a predetermined learning condition is met, the amount of correction for the feedback control and the like are learned. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-084263 A Summary of the Invention [Problem to be solved by the invention]

[0004] Some hybrid vehicles can run by switching between a series hybrid state and a parallel hybrid state. A series hybrid is configured to generate power from the engine using a first motor capable of generating electricity to charge a battery, and to run using power from a second motor using electric power from the first motor and the battery. A parallel hybrid is configured to run by adding power input and output from the first motor to the power from the engine and outputting the result as power for running, and also outputting power from the second motor as power for running. When running in the parallel hybrid state, the engine speed corresponds to the vehicle speed, so if feedback control of the idle speed is performed when the engine is in an idle state, the control will fail.

[0005] The main object of the hybrid vehicle of the present invention is to perform ISC control, which sets the engine speed to the idle speed, more appropriately without causing the control to fail. [Means for solving the problem]

[0006] The hybrid vehicle of the present invention employs the following means to achieve the above-mentioned main object.

[0007] The hybrid vehicle of the present invention is A hybrid vehicle having an engine, a first motor capable of generating electricity connected to a crankshaft of the engine, a second motor, and a control device that controls the engine, the first motor, and the second motor, the hybrid vehicle being capable of running by switching a connection state between the engine, the first motor, and the second motor between a series hybrid state and a parallel hybrid state, the control device prohibits an idle speed control for setting a rotation speed of the engine to a predetermined idle rotation speed and / or prohibits learning in the idle speed control when a connection state between the engine, the first motor, and the second motor is in the parallel hybrid state. It is characterized by:

[0008] In the hybrid vehicle of the present invention, when the connection state of the engine, the first motor, and the second motor is in a parallel hybrid state, idle speed control (hereinafter referred to as ISC control) in which the engine speed is set to a predetermined idle speed and learning of the ISC control are prohibited. This makes it possible to prevent the ISC control from failing in the parallel hybrid state in which the engine speed is in accordance with the vehicle speed. Of course, when the connection state of the engine, the first motor, and the second motor is in a series hybrid state, the ISC control and learning of the ISC control are performed, so that the ISC control can be performed more appropriately. As a result, the ISC control in which the engine speed is set to the idle speed can be performed more appropriately without failing. Here, the series hybrid state is a connection configuration in which the power from the engine is generated by the first motor capable of generating electricity to charge the battery, and the vehicle runs on the power from the second motor using the power from the first motor and the battery. The parallel hybrid state is a connection configuration in which power input / output from the first motor is added to the power from the engine and output as power for running, and power from the second motor is also output as power for running. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. [Diagram 2] 13 is a flowchart showing an example of an ISC control permission / refusal process executed by the HVECU 50. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, a mode for carrying out the present invention will be described using examples. EXAMPLES

[0011] 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 according to the embodiment includes an engine 22, a motor MG1, a motor MG2, a clutch 26, an automatic transmission 30, a battery 44, and a hybrid electronic control unit (hereinafter referred to as HVECU) 50.

[0012] The engine 22 is configured as a multiple-cylinder internal combustion engine that uses fuel such as gasoline or diesel to output power through four strokes: intake, compression, expansion, and exhaust, and a rotor and clutch 26 of the motor MG1 are connected to a crankshaft 23 of the engine 22. The engine 22 is controlled by an engine electronic control unit (hereinafter referred to as engine ECU) 24.

[0013] The engine ECU 24 is configured as a microcomputer centered on a CPU, and in addition to the CPU, has a ROM for storing programs, a RAM for temporarily storing data, a flash memory for non-volatilely storing data, an input / output port, a communication port, etc. Signals from various sensors for detecting the state of the engine 22 are input to the engine ECU 24 via an input port. In addition, the engine ECU 24 outputs a drive signal to a throttle valve, a drive signal to a fuel injection valve, an ignition drive signal to an ignition plug, etc. via an output port. The engine ECU 24 is connected to the HVECU 50 via the communication port, and performs intake air amount control, fuel injection control, ignition control, etc. for the engine 22 based on control signals from the HVECU 50 to drive and control the engine 22.

[0014] The motor MG1 is configured as, for example, a synchronous generator motor capable of generating electricity. The motor MG1 generates electricity using power from the engine 22 to supply the electricity to a battery 44 and the motor MG1, and outputs power to the crankshaft 23 of the engine 22 using the power from the battery 44. The motor MG1 is driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40 by controlling the switching of a switching element (not shown) of an inverter 41.

[0015] The motor MG2 is configured as, for example, a synchronous generator motor capable of generating electricity. The motor MG2 inputs and outputs power for running to an axle connected to the front wheels 35a, 35b via a differential gear 34. The motor MG2 is driven and controlled by the motor ECU 40 by controlling the switching of a switching element (not shown) of the inverter 42.

[0016] The motor ECU 40 is configured as a microcomputer with a CPU at its core, and in addition to the CPU, has a ROM for storing programs and the like, a RAM for temporarily storing data, a flash memory for non-volatilely storing data, an input / output port, a communication port, etc. The motor ECU 40 is connected to the HVECU 50 via the communication port, and performs switching control of switching elements (not shown) of the inverter 41 and the inverter 42 based on control signals from the HVECU 50.

[0017] The automatic transmission 30 is configured as an automatic transmission capable of shifting between six forward gears and one reverse gear, or eight forward gears and one reverse gear, etc., by hydraulic drive. The input shaft of the automatic transmission 30 is connected to the crankshaft 23 of the engine 22 via the clutch 26, and the output shaft is connected to a drive shaft 36 which is connected via a differential gear 37 to an axle to which rear wheels 38a, 38b are connected. The automatic transmission 30 is driven and controlled by an automatic transmission electronic control unit (hereinafter referred to as ATECU) 32.

[0018] The ATECU 32 is configured as a microcomputer centered around a CPU, and in addition to the CPU, has a ROM for storing programs and the like, a RAM for temporarily storing data, a flash memory for non-volatilely storing data, an input / output port, a communication port, etc. The ATECU 40 is connected to the HVECU 50 via the communication port, and changes the gear position of the automatic transmission 30 by adjusting the hydraulic pressure of a hydraulic circuit (not shown) based on a control signal from the HVECU 50.

[0019] The battery 44 is, for example, a lithium ion battery or a nickel-hydrogen battery, and is attached to a power line to which the inverters 41 and 42 are connected.

[0020] The HVECU 50 is configured as a microcomputer centered on a CPU, and in addition to the CPU, has a ROM for storing programs, a RAM for temporarily storing data, a flash memory for non-volatilely storing data, an input / output port, a communication port, etc. Signals from various sensors are input to the HVECU 50 via the input port. Examples of signals input to the HVECU 50 include an ignition signal from an ignition switch 60, a shift position SP from a shift position sensor 62 that detects the operation position of a shift lever 61, an accelerator opening Acc from an accelerator pedal position sensor 64 that detects the amount of depression of an accelerator pedal 63, a brake pedal position BP from a brake pedal position sensor 66 that detects the amount of depression of a brake pedal 65, and a vehicle speed V from a vehicle speed sensor 68.

[0021] The hybrid vehicle 20 of the embodiment thus configured can run by switching between a series hybrid state in which the clutch 26 is disengaged and a parallel hybrid state in which the clutch 26 is engaged. In the series hybrid state (clutch 26 is off), the motor MG1 generates electricity using power from the engine 22, and supplies the electricity to the battery 44 and the motor MG2, while outputting the power from the motor MG2 to the front wheels 35a, 35b to run. In the parallel hybrid state (clutch 26 is on), the power input / output from the motor MG1 is added to the power from the engine 22, and the power is shifted by the automatic transmission 30 to be output to the rear wheels 38a, 38b, while the power from the motor MG2 is input / output to the front wheels 35a, 35b to run.

[0022] Next, the operation of the hybrid vehicle 20 of the embodiment, particularly the operation when the engine 22 is idling, will be described. Fig. 2 is a flow chart showing an example of ISC control (idle speed control) permission / prohibition processing executed by the HVECU 50. The ISC control is a control for adjusting the throttle opening by feedback control so that the rotation speed Ne of the engine 22 becomes a predetermined idle rotation speed Nidl (for example, 600 rpm, 800 rpm, 1000 rpm, etc.). In order to perform the ISC control more accurately, ISC learning is also performed. The ISC learning is a process for storing a correction value for feedback control when a condition is established in which the rotation speed Ne of the engine 22 is approximately equal to the idle rotation speed Nidl by the ISC control.

[0023] When the ISC control permission / prohibition process is executed, the HVECU 50 first determines whether or not the connection state of the engine 22, the motor MG1, and the motor MG2 is a parallel hybrid state (step S100). The determination of whether or not the connection state is a parallel hybrid state can be made by checking whether or not the clutch 26 is in an on state (connected state).

[0024] When it is determined in step S100 that the connection state of the engine 22, the motor MG1, and the motor MG2 is the parallel hybrid state (the clutch 26 is on), the ISC control and ISC learning are prohibited (step S110), and this process ends. In the parallel hybrid state, the crankshaft 23 of the engine 22 is connected to the rear wheels 38a, 38b via the clutch 26, the automatic transmission 30, and the differential gear 37, so that the rotation speed Ne of the engine 22 is the vehicle speed multiplied by the gear ratio of the automatic transmission 30. For this reason, if the ISC control is executed to operate the engine 22 at the idle rotation speed Nidl, the ISC control will fail. In order to avoid such a failure of the ISC control, the ISC control and the ISC learning are prohibited in the parallel hybrid state.

[0025] When it is determined in step S100 that the connection state of the engine 22, the motor MG1, and the motor MG2 is not a parallel hybrid state (the clutch 26 is on), that is, when it is determined that the connection state of the engine 22, the motor MG1, and the motor MG2 is a series hybrid state, the ISC control and ISC learning are permitted (step S120), and this process is terminated. In the series hybrid state, the clutch 26 is off, so that the engine 22 can be operated at a free rotation speed regardless of the vehicle speed. Therefore, even if the ISC control is performed when the engine 22 is operated at the idle rotation speed Nidl, the ISC control will not fail. In addition, the ISC learning for learning the correction value of the feedback control in the ISC control can also be performed appropriately. Therefore, the ISC control and ISC learning are permitted in the series hybrid state to perform the ISC control appropriately.

[0026] In the hybrid vehicle 20 of the embodiment described above, when the connection state of the engine 22, the motor MG1, and the motor MG2 is the parallel hybrid state (the clutch 26 is on), the ISC control and ISC learning are prohibited. This makes it possible to prevent the ISC control from failing due to the execution of the ISC control when the engine 22 is operating at the idle speed Nidl. On the other hand, when the connection state of the engine 22, the motor MG1, and the motor MG2 is the series hybrid state (the clutch 26 is off), the ISC control and ISC learning are permitted. This makes it possible to perform the ISC control and ISC learning more appropriately. As a result, the ISC control that sets the rotation speed Ne of the engine 22 to the idle speed Nidl can be performed more appropriately without failure.

[0027] The hybrid vehicle 20 of the embodiment includes the engine ECU 24, the motor ECU 40, the ATECU 32, and the HVECU 50, but any two or three of these electronic control units may be configured as a single electronic control unit. Also, the engine ECU 24, the motor ECU 40, the ATECU 32, and the HVECU 50 may all be configured as a single electronic control unit.

[0028] The relationship between the main elements of the embodiment and the main elements of the invention described in the section on Means for Solving the Problems will be described below. In the embodiment, the engine 22 corresponds to the "engine", the motor MG1 corresponds to the "first motor", the motor MG2 corresponds to the "second motor", and the engine ECU 24, the motor ECU 40, the ATECU 32, and the HVECU 50 correspond to the "control device".

[0029] The correspondence between the main elements of the Examples and the main elements of the invention described in the Summary of the Problem column does not limit the elements of the invention described in the Summary of the Problem column, since the Examples are examples for specifically explaining the mode for implementing the invention described in the Summary of the Problem column. In other words, the interpretation of the invention described in the Summary of the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Summary of the Problem column.

[0030] Although the form for carrying out the present invention has been described above using examples, the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the gist of the present invention. [Industrial Applicability]

[0031] The present invention can be used in the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0032] 20 automobile, 22 engine, 23 crankshaft, 24 engine electronic control unit (engine ECU), 26 clutch, 30 automatic transmission, 32 automatic transmission electronic control unit (ATECU), 34 differential gear, 35a, 35b front wheels, 36 drive shaft, 37 differential gear, 38a, 38b rear wheels, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 44 battery, 50 hybrid electronic control unit (HVECU), 60 ignition switch, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 brake pedal, 66 brake position sensor, 68 vehicle speed sensor.

Claims

[Claim 1] A hybrid vehicle having an engine, a first motor capable of generating electricity connected to a crankshaft of the engine and connected to an input shaft of a transmission whose output shaft is connected to a drive shaft via a clutch, a second motor, and a control device that controls the engine, the first motor, and the second motor, and capable of running by switching a connection state between the engine, the first motor, and the second motor between a series hybrid state in which the clutch is off and a parallel hybrid state in which the clutch is on, the control device, when a connection state of the engine, the first motor, and the second motor is in the parallel hybrid state, prohibits an idle speed control for setting a rotation speed of the engine to a predetermined idle rotation speed and prohibits learning in the idle speed control. A hybrid vehicle characterized by

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