JP6079521B2 - Hybrid vehicle - Google Patents

Description

  The present invention relates to a hybrid vehicle having an internal combustion engine and a motor as drive sources.

  For example, Patent Document 1 includes an internal combustion engine having a starter motor as a vehicle drive source and an electric motor having a power generation function, and the internal combustion engine and the electric motor are connected via a first clutch. And a transmission in which a transmission is connected via a second clutch. In the hybrid vehicle disclosed in Patent Document 1, when both the first clutch and the second clutch are engaged, the output torque of the internal combustion engine can be transmitted to the drive wheels, and the first clutch is not engaged. When only the second clutch is engaged, only the output torque of the electric motor can be transmitted to the drive wheels.

JP 2013-159330 A

  In such a hybrid vehicle disclosed in Patent Document 1, if the first clutch fails in a situation where the output torque of the internal combustion engine is required, the output torque of the internal combustion engine can be transmitted to the drive wheels. Disappear. Therefore, if such a state continues, a sufficient driving torque is not transmitted to the driving wheels even though the internal combustion engine is operated, and the battery that supplies power to the motor is excessively discharged, and the battery Depending on the state, there is a risk that the battery must be replaced.

  The hybrid vehicle of the present invention includes an internal combustion engine and a motor as drive sources, a first clutch is interposed between the internal combustion engine and the motor, and a second clutch is interposed between the motor transmission. . When the internal combustion engine is started by the starter motor and the vehicle is started using the output torque of the internal combustion engine, the hydraulic pump is driven by the rotational driving force of the motor within a predetermined time. If one clutch cannot be engaged, the motor is stopped and the internal combustion engine is stopped.

  According to the present invention, when the internal combustion engine is started by the starter motor and the vehicle is started using the output torque of the internal combustion engine, if the first clutch cannot be engaged, the motor is stopped and the internal combustion engine is stopped. Therefore, excessive discharge of the battery that supplies power to the motor generator can be prevented, and this battery can be protected.

BRIEF DESCRIPTION OF THE DRAWINGS The structure explanatory drawing which shows the system structure of the hybrid vehicle to which this invention is applied. The characteristic view which shows the characteristic of the mode switching of a hybrid vehicle. Explanatory drawing which showed typically an example of the starting sequence of a hybrid vehicle. The timing chart at the time of implementing 1st starting mode. The flowchart which shows the flow of control at the time of implementing 1st starting mode.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing a system configuration of an FF (front engine / front drive) type hybrid vehicle as an example of a hybrid vehicle to which the present invention is applied.

  This hybrid vehicle includes an engine 1 as an internal combustion engine and a motor generator 2 as a motor as drive sources of the vehicle, and a belt-type continuously variable transmission 3 as a transmission. A first clutch 4 is interposed between the engine 1 and the motor generator 2, and a second clutch 5 is interposed between the motor generator 2 and the belt type continuously variable transmission 3.

  The engine 1 is composed of, for example, a gasoline engine, and based on a control command from the engine controller 21, start control and stop control are performed, the throttle valve opening is controlled, and fuel cut control is performed.

  The first clutch 4 provided between the output shaft of the engine 1 and the rotor of the motor generator 2 couples the engine 1 to the motor generator 2 or connects the engine 1 to the motor generator 2 according to the selected travel mode. The engagement / release is controlled by the first clutch hydraulic pressure generated by the oil pump 7 as a hydraulic pump based on the control command from the clutch controller 22. The first clutch 4 of the present embodiment has a normally open configuration, and is in a released state while the oil pump 7 is stopped, and is in a state that can be engaged while the oil pump 7 is operating.

  The oil pump 7 is a mechanical pump that is operated by the rotational driving force of the motor generator 2. For example, a gear pump or a vane pump is used. The input gear of the oil pump 7 is connected to the output shaft 2 a of the motor generator 2 via a chain 8.

  The motor generator 2 is composed of, for example, a three-phase alternating current synchronous motor generator, and is connected to a high voltage circuit 11 including a high voltage battery 12, an inverter 13, and a high voltage relay 14. Based on a control command from the motor controller 23, the motor generator 2 receives a power supply from the high-voltage battery 12 via the inverter 13 and outputs a positive torque, and absorbs the torque. Both the regenerative operation of generating power and charging the high voltage battery 12 via the inverter 13 is performed.

  The second clutch 5 provided between the rotor of the motor generator 2 and the input shaft of the belt type continuously variable transmission 3 is between a vehicle drive source including the engine 1 and the motor generator 2 and the drive wheels 6 (front wheels). Is transmitted and disconnected, and engagement / release is controlled by the second clutch oil pressure generated by the oil pump 7 based on a control command from the clutch controller 22. In particular, the second clutch 5 can be set in a slip engagement state in which power is transmitted with slip by variable control of the transmission torque capacity, and enables smooth start in a configuration without a torque converter. At the same time, the realization of creep running is being attempted.

  Here, the second clutch 5 is not actually a single friction element, but the forward clutch 42 or the reverse brake 43 in the forward / reverse switching mechanism provided at the input portion of the belt-type continuously variable transmission 3 is the second clutch 5. Used as The forward / reverse switching mechanism that switches the input rotation direction to the belt-type continuously variable transmission 3 between the forward rotation direction during forward travel and the reverse rotation direction during reverse travel includes a sun gear 41a, a ring gear 41b, a planet carrier 41c, and the like. A planetary gear mechanism 41, a forward clutch 42 that is fastened during forward travel, and a reverse brake 43 that is fastened during reverse travel, and the forward clutch 42 functions as the second clutch 5 during forward travel, The reverse brake 43 functions as the second clutch 5 during traveling. In a state where both the forward clutch 42 and the reverse brake 43 serving as the second clutch 5 are released, torque transmission is not performed, and the rotor of the motor generator 2 and the belt type continuously variable transmission 3 are substantially disconnected. In this embodiment, both the forward clutch 42 and the reverse brake 43 have a so-called normally open configuration.

  The belt-type continuously variable transmission 3 includes an input-side primary pulley, an output-side secondary pulley, and a metal belt wound between the two, and is based on a control command from the transmission controller 24. The primary hydraulic pressure and secondary hydraulic pressure generated by the oil pump 7 continuously control the belt contact radius of each pulley and the gear ratio. The input shaft 3 a of the belt type continuously variable transmission 3 is connected to the sun gear 41 a, and the output shaft 3 b is connected to the drive wheels 6 via a final reduction mechanism 45.

  The engine 1 includes a starter motor 16 for starting. The starter motor 16 is a direct current motor having a lower rated voltage than the motor generator 2, and is connected to a weak electric circuit 15 including a DC / DC converter 17, a low voltage battery 18, and a weak electric relay 19. The starter motor 16 is driven based on a control command from the engine controller 21 and performs cranking of the engine 1.

  The low voltage battery 18 is charged via the DC / DC converter 17 by the power from the high voltage circuit 11 including the high voltage battery 12. The charged electric power is supplied to a light control circuit 15 such as a vehicle control system including the engine controller 21 and the like, a vehicle air conditioner, an audio device, and lighting.

  The hybrid vehicle control system includes an integrated controller 26 that performs integrated control of the entire vehicle, in addition to the engine controller 21, clutch controller 22, motor controller 23, and transmission controller 24 described above. 22, 23, 24, and 26 are connected via a CAN communication line 27 capable of exchanging information with each other. The accelerator opening sensor 31, the engine speed sensor 32 that detects the speed of the engine 1, the vehicle speed sensor 33, the motor speed sensor 34 that detects the speed of the motor generator 2, and the voltage of the high-voltage battery 12 are detected. The battery voltage sensor 35, the battery temperature sensor 36 for detecting the temperature of the high voltage battery 12, the battery voltage sensor 37 for detecting the voltage of the low voltage battery 18, the battery temperature sensor 38 for detecting the temperature of the low voltage battery 18, and the oil pump 7 Various sensors such as an oil temperature sensor 39 for detecting the oil temperature of the hydraulic oil discharged from the engine are provided, and detection signals from these sensors are sent individually to each controller such as the integrated controller 26 or the CAN communication line 27. Is entered through.

  The hybrid vehicle configured as described above includes an electric vehicle travel mode (hereinafter referred to as “EV mode”), a hybrid travel mode (hereinafter referred to as “HEV mode”), and a drive torque control start mode (hereinafter referred to as “EV mode”). The driving mode is selected according to the driving state of the vehicle, the accelerator operation of the driver, and the like.

  The “EV mode” is a mode in which the first clutch 4 is in a disengaged state and travels using only the motor generator 2 as a drive source, and includes a motor travel mode and a regenerative travel mode. This “EV mode” is selected when the driving force required by the driver is relatively low.

  The “HEV mode” is a mode in which the first clutch 4 is engaged and travels using the engine 1 and the motor generator 2 as drive sources, and includes a motor assist travel mode, a travel power generation mode, and an engine travel mode. This “HEV mode” is selected when the required driving force by the driver is relatively large and when there is a request from the system based on the state of charge (SOC) of the high-voltage battery 12 or the driving state of the vehicle. .

  The “WSC mode” is a case where the first clutch 4 is mainly engaged and the engine 1 and the motor generator 2 are used as driving sources, and is selected particularly in a region where the vehicle speed is relatively low such as when the vehicle starts. In this mode, the transmission torque capacity of the second clutch 5 is variably controlled while controlling the rotational speed of the motor generator 2, thereby bringing the second clutch 5 into a slip engagement state. With the “WSC mode”, the engine 1 can be used as a drive source even when the target input rotational speed of the belt-type continuously variable transmission 3 is an extremely low vehicle speed that is lower than the engine idling rotational speed.

  FIG. 2 shows basic switching characteristics of the “EV mode”, “HEV mode”, and “WSC mode” based on the vehicle speed VSP and the accelerator opening APO. As shown in the figure, “HEV → EV switching line” for shifting from “HEV mode” to “EV mode”, and conversely “EV → HEV switching line” for shifting from “EV mode” to “HEV mode” It is set to have appropriate hysteresis. Further, in the area below the predetermined vehicle speed VSP1, the “WSC mode” is set.

  In such a hybrid vehicle, as shown in FIG. 3, when a driver requests to start the system by a key operation such as pressing a push button, a predetermined start sequence is set so that the vehicle can be driven (ReadyON). carry out. As an example, FIG. 3 schematically shows a flow of a first activation mode described later with a solid line, and schematically shows a flow of the second activation mode with a broken line.

  For example, when the torque that can be output from the motor generator 2 is small when the system is requested to start, the starter motor 16 starts the engine 1 and selects the first start mode so that the engine 1 can run with the output torque. To do. In the first start mode, starter control for starting the engine 1 with the starter motor 16 is performed, and then the high voltage relay 14 is turned on to electrically connect the high voltage battery 12 and the motor generator 2 (high voltage connection) before starting. As a preparation, the motor generator 2 is started, the hydraulic pressure of the first clutch 4 is generated, and the first clutch 4 is engaged to make the hybrid vehicle travelable. In addition, by engaging the first clutch 4, the hydraulic pressure can be generated by the driving force of the engine 1. Further, when the torque that can be output from the motor generator 2 can be sufficiently secured for starting the hybrid vehicle when the system is requested to start, the engine 1 is driven without the engine 1 being started. The second activation mode is selected so that it can. In the second start mode, the high-voltage relay 14 is turned on to electrically connect the high-voltage battery 12 and the motor generator 2 (high-power connection), and the motor generator 2 is started as a pre-startup preparation. Is generated so that the hybrid vehicle can run.

  Here, when the first clutch 4 cannot be engaged due to a failure or the like when the first activation mode is performed, the engine 1 and the motor generator 2 are continuously driven without reaching the travelable state. That is, when the first clutch 4 cannot be engaged, the hydraulic pressure cannot be generated by the driving force of the engine 1, so that the generation of the hydraulic pressure by the driving force of the motor generator 2 must be continued. Therefore, the high voltage battery 12 that supplies power to the motor generator 2 continues to be discharged.

  The first start mode is selected in a situation where the output torque of the motor generator 2 is low, that is, the high voltage battery 12 cannot output. As a situation where the high voltage battery 12 cannot output, for example, when the temperature of the high voltage battery 12 is low, the battery SOC of the high voltage battery 12 is low, or the like. Therefore, if the motor generator 2 is continuously driven in such a situation (in the first start-up mode), the high voltage battery 12 is excessively discharged and deteriorates. In some cases, the high voltage battery 12 is repaired. , Will have to be replaced.

  Therefore, when the system is started in the first start mode and the hybrid vehicle is allowed to run, when the first clutch 4 cannot be engaged within a predetermined time T after it is determined that the engine 1 has completely exploded. Then, it is determined that the first clutch 4 has failed, and the drive of the motor generator 2 is stopped, the drive of the engine 1 is stopped, and the start of the hybrid vehicle system is stopped.

  Thereby, excessive discharge of the high voltage battery 12 can be prevented, and the high voltage battery 12 can be protected. Further, the engine 1 once started is stopped, and the start of the system is stopped, so that the driver can be surely informed that there is an abnormality in the hybrid vehicle.

  FIG. 4 shows a timing chart when the first activation mode is implemented. The driver makes an activation request by key operation (time t1), and selects an activation mode between times t1 and t2. When the first start mode is selected as the start mode, cranking of the engine 1 by the starter motor 16 is started from time t2. At time t3, when it is determined that the rotation speed of the engine 1 is equal to or higher than the predetermined rotation speed and complete explosion has occurred, the high-power relay 14 is turned on to start supplying power from the high-voltage battery 12 to the high-power circuit 11 at time t4. The motor generator 2 starts. When the oil pump 7 is activated by starting the motor generator 2 and the hydraulic pressure (line pressure) of the first clutch 4 is stabilized, an engagement command (CL1 transmission torque capacity indicated by a broken line) for the first clutch 4 is issued, and the first Engagement of the first clutch 4 (CL1 transmission torque capacity indicated by a solid line) is started by an engagement command of the clutch 4. At time t5, the engagement determination of the first clutch 4 is started. In the determination of engagement of the first clutch 4, for example, the rotational speed difference between the rotational speed of the engine 1 and the rotational speed of the motor generator 2 is equal to or smaller than a predetermined rotational speed difference (for example, 150 rpm or lower), and the output torque of the motor generator 2 is predetermined. If it is less than the value (for example, 1 Nm or less), it is determined that the first clutch 4 is engaged. When it is determined that the engagement of the first clutch 4 is completed at time t6, the output torque of the engine 1 is increased and the output torque of the motor generator 2 is decreased (negative value). This is because when the first clutch 4 is engaged, the rotational speed of the engine 1 is lower than that before the first clutch 4 is engaged, and the rotational speed of the motor generator 2 is higher than that before the first clutch 4 is engaged. It is. In FIG. 4, the rotational speed and torque of the engine 1 are the rotational speed and torque indicated by thick solid lines, respectively, and the rotational speed and torque of the motor generator 2 are the rotational speed and torque indicated by thin solid lines, respectively.

  Time t7 is the time when a predetermined time T has elapsed from time t3 when it is determined that the engine 1 has completely exploded. The hydraulic pressure of the first clutch 4 is set so that the predetermined time T becomes longer as the hydraulic oil temperature at the time of start-up becomes lower, since the rising of the hydraulic pressure changes according to the hydraulic oil temperature. . If it is not determined that the first clutch 4 is engaged within the predetermined time T, the motor generator 2 and the engine 1 are stopped, and the system is stopped.

  Thus, by setting the predetermined time T according to the oil temperature of the hydraulic oil, it is possible to determine the engagement of the first clutch 4 as quickly as possible, and thus unnecessary discharge of the high voltage battery 12. Can be suppressed.

  FIG. 5 is a flowchart showing the flow of control when the first activation mode is implemented. In S1, it is determined whether or not the starter motor 16 is to be started. If the starter motor 16 is to be started, the process proceeds to S2. In step 2, it is determined whether or not the engine 1 has completely exploded. If it is determined that the engine 1 has completely exploded, the process proceeds to S3. In S3, it is determined whether or not the first clutch 4 is engaged. If it is determined that the first clutch 4 is engaged, it is determined that the hybrid vehicle is ready to run (ReadyON) (S4), and the current routine is terminated. When the 1st clutch 4 is not fastened, it progresses to S5 and it is determined whether predetermined time T has passed since the engine 1 completed explosion. If the predetermined time T has elapsed after the complete explosion, it is determined that the first clutch 4 cannot be engaged due to a failure (Fail) (S6), the engine 1 and the motor generator 2 are stopped, and the system is stopped. .

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Motor generator 3 ... Belt type continuously variable transmission 4 ... 1st clutch 5 ... 2nd clutch 12 ... High voltage battery 21 ... Engine controller 22 ... CVT controller 23 ... Motor controller 26 ... Integrated controller 27 ... CAN communication line

Claims (7)

An internal combustion engine and a motor as drive sources;
A starter motor capable of starting the internal combustion engine;
A battery for supplying power to the motor;
A first clutch interposed between the internal combustion engine and the motor;
A second clutch interposed between the motor and the transmission;
In a hybrid vehicle having a hydraulic pump that operates by the rotational driving force of the motor and generates the hydraulic pressure of the first clutch,
When the internal combustion engine is started by the starter motor and the vehicle is started using the output torque of the internal combustion engine, the first pump pump is driven within a predetermined time while the hydraulic pump is driven by the rotational driving force of the motor. If the clutch cannot be engaged, the hybrid vehicle is characterized in that the motor is stopped and the internal combustion engine is stopped.   As a start mode at the time of vehicle start by a driver's key operation, a first start mode for starting using the output torque of the internal combustion engine, and a second start mode for starting using only the output torque of the motor, The hybrid vehicle according to claim 1, further comprising:   The predetermined time is an elapsed time from the start of the internal combustion engine, and is set to become shorter as the temperature of the hydraulic oil of the first clutch becomes higher. Hybrid vehicle.   The vehicle is started using the output torque of the internal combustion engine by starting the internal combustion engine with the starter motor when the battery SOC of the battery is low when the vehicle is started by a key operation of a driver. Item 4. The hybrid vehicle according to any one of Items 1 to 3.   The starter motor is used to start the internal combustion engine and start the vehicle using the output torque of the internal combustion engine when the temperature of the battery is low when the vehicle starts by a key operation of a driver. The hybrid vehicle in any one of 1-4.   The hybrid vehicle according to any one of claims 1 to 5, wherein when the first clutch cannot be engaged during the predetermined time after the internal combustion engine is started, the first clutch is determined to be faulty. .   The first clutch is configured to be in a disengaged state when the hydraulic pump is stopped and to be able to be engaged while the hydraulic pump is operating. Hybrid vehicle.

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