JP2005253151A - Controller of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of a hybrid vehicle in which a drive motor, and the like, can be protected by reducing waste of a battery while ensuring a required sufficient driving force even when the hybrid vehicle runs into stall state. <P>SOLUTION: When action of an accelerator and a brake is detected and the detection value from a motor output detecting means is not lower than a set value, motor output is lowered gradually based on a predetermined motor output lowering rate. When the vehicle speed is not lower than a set value, the motor output lowering rate is set larger than that when the vehicle speed is lower than the set value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control device for a hybrid vehicle that operates during a stall.

  There are a series type, a parallel type, and a series / parallel type as a driving method of a hybrid vehicle that uses an engine and a driving motor together as a power source of the vehicle. The series type is a driving method in which electric power generated by a generator is charged in a battery and a vehicle is driven by a drive motor driven by the electric power of the battery, and an engine is used to drive the generator. In the parallel type, the engine is the main source of the drive, and when the engine is under load or acceleration, the drive motor is used as a power source to assist the driving force, and when the load is light, it is operated as a generator to charge the battery. This is a driving method.

  The series / parallel system is a vehicle drive system that independently includes a generator and a drive motor in addition to the engine. The series-parallel type is distinguished from the parallel type in that the generator can be operated by the engine even when the drive motor is operating, but it can be divided into the drive by the engine alone and the drive by the drive motor alone depending on the driving situation of the vehicle. This is common to the parallel type in that it travels by switching to drive using both as drive sources. In order to transmit the engine output to the drive wheels according to the driving conditions of the vehicle, the hybrid vehicle adopting the parallel type or series / parallel type drive system and the power transmission state that transmits the engine output to the drive wheels and the power that is not transmitted A clutch mechanism for switching to the disconnected state is incorporated.

By the way, in a hybrid vehicle using a drive motor as a power source, when a braking force is applied to the motor drive shaft in a state where current is supplied to drive the drive motor, the drive motor enters a stalled state. When a stall occurs, the battery is wasted, and the temperature of the drive motor, inverter, etc. rises and the output must be limited, or the durability may be impaired. In this regard, Patent Document 1 discloses a technique for reducing the power consumption of a battery as a control device applied to an electric vehicle by setting a current upper limit value at the time of stalling when a stall is detected and suppressing the current value flowing through the motor. It is disclosed.
JP 2002-262402 A

  Up to now, the applicant of the present application has received power from a transmission input shaft to which engine power is input, a front wheel output shaft connected to the transmission input shaft via a clutch mechanism, and a generator directly connected to the engine. A technology relating to a hybrid vehicle including a motor drive shaft that is mounted with a drive motor that is used and connected to a front wheel output shaft has been developed (see Japanese Patent Application No. 2003-196915). In this hybrid vehicle, in particular, between the start state and the medium speed range, the drive motor is operated while generating power by performing rated operation in an efficient region while the clutch mechanism is switched to the power cut off state. It is possible to travel by.

  By the way, in a vehicle that can start with a single drive motor, the drive motor, inverter, etc. are effectively protected against situations where a stall is likely to occur, such as when the driver intentionally starts a stall or starts a slope. There is a need to. Further, it is necessary to suppress the waste of the battery due to the stall and to secure the driving force necessary for starting.

  An object of the present invention is to control a hybrid vehicle capable of reducing battery waste and protecting a drive motor, an inverter, and the like while securing a necessary and sufficient driving force even when the hybrid vehicle falls into a stalled state. To provide an apparatus.

  The hybrid vehicle control device of the present invention includes a generator driven by an engine, a drive motor driven by using electric power from the generator, a power transmission state in which engine power is transmitted to driving wheels, and power that is not transmitted. A control device for a hybrid vehicle comprising a clutch mechanism for switching to a cut-off state, the accelerator detecting means for detecting the operation of the accelerator, the brake detecting means for detecting the operation of the brake, and the motor output of the drive motor The motor output detecting means, the operation of the accelerator and the brake are detected, and if the detected value by the motor output detecting means is equal to or higher than a set value, the motor output is gradually reduced based on a predetermined motor output reduction rate. Motor output limiting means.

  The control apparatus for a hybrid vehicle according to the present invention is characterized in that the motor output limiting means is executed under a state where the clutch mechanism is switched to a power cut-off state.

  The hybrid vehicle control device of the present invention has vehicle speed detection means for detecting the vehicle speed, and the motor output reduction rate when the detection value by the vehicle speed detection means is equal to or greater than a set value is lower than when the motor output decrease rate is less than the set value. It is characterized by a large setting.

  According to the present invention, when the predetermined motor output restriction condition is satisfied, the motor output can be gradually decreased based on the predetermined motor output decrease rate, so that the necessary and sufficient driving force is ensured, Battery waste can be reduced, and the drive motor, inverter, etc. can be effectively protected. In particular, the motor output reduction rate can be appropriately set according to the vehicle speed. For example, when a vehicle running at a predetermined speed or higher falls into a stalled state, the motor output reduction rate is set to a large value by setting the motor output reduction rate large. It is possible to quickly reduce waste and protect the drive motor, inverter, and the like.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a skeleton diagram showing an embodiment of a hybrid vehicle to which the present invention is applied.

  This hybrid vehicle includes an engine 10 and a drive motor 11 as two power sources, and the engine 10 is a vertically mounted engine including a crankshaft 10a arranged in the traveling direction of the vehicle. A generator 12, a front differential mechanism 13, and a transmission 14 are provided between the engine 10 and the drive motor 11. The transmission 14 incorporated in the gear case 17 includes a transmission input shaft 15 and a front wheel output shaft 16 which are parallel to each other. The transmission input shaft 15 is connected to the transmission mechanism 15 via a clutch mechanism 18 and a generator 12. While the engine 10 is connected, a front differential mechanism 13 and a drive motor 11 are connected to the front wheel output shaft 16.

  A generator case 19 is assembled on the vehicle front side of the gear case 17, and the generator 12 is accommodated in the generator case 19. The generator 12 includes a rotor 12a and a stator 12b. The rotor 12a is connected to the crankshaft 10a of the engine 10, and the stator 12b is fixed to the generator case 19 so as to surround the rotor 12a. Since the rotor 12a is connected to the crankshaft 10a, power can be generated by driving the engine 10.

  An engine output shaft 20 is connected to the crankshaft 10a via a rotor 12a, and the engine output shaft 20 is driven by engine power. A clutch mechanism 18 is provided between the engine output shaft 20 and the transmission input shaft 15. When the clutch mechanism 18 is engaged, the engine power is transmitted to the transmission input shaft 15 and the engagement is released. Transmission of engine power is interrupted. The clutch mechanism 18 is an electromagnetic clutch that is switched to the engaged state by exciting the electromagnetic coil 18a and switched to the disconnected state by releasing the excitation.

  Two transmission gears 21 a and 22 a are rotatably provided on the transmission input shaft 15, and two driven gears 21 b and 22 b are fixed to the front wheel output shaft 16. The drive gears 21a, 22a and the driven gears 21b, 22b are always meshed to form a low-speed gear stage and a high-speed gear train, and the transmission input shaft 15 is driven by either the low-speed gear stage or the high-speed gear stage. A synchronous switching mechanism 23 for switching to the transmission state is provided. The synchronization switching mechanism 23 is a synchromesh mechanism, and includes a synchromesh hub 23a fixed to the transmission input shaft 15 and a synchromesh sleeve 23b that is always meshed therewith. When the synchro sleeve 23b is engaged with the drive gear 21a, the low speed stage is in a power transmission state, and when the synchro sleeve 23b is engaged with the drive gear 22a, the high speed stage is in a power transmission state.

  The front wheel output shaft 16 is driven by engine power by engaging the clutch mechanism 18 and switching the low speed stage or the high speed stage to the power transmission state. A drive pinion gear 25 that meshes with the ring gear 24 of the front differential mechanism 13 is fixed to one end of the front wheel output shaft 16, and engine power passing through the front wheel output shaft 16 is transmitted to the left and right front wheels via the front differential mechanism 13. It is to be distributed.

  Further, a connecting shaft 26 is rotatably accommodated in the gear case 17 in parallel with the front wheel output shaft 16. A transmission gear 27 is fixed to the connecting shaft 26, and a transmission gear 28 that always meshes with the transmission gear 27 is fixed to the front wheel output shaft 16. The front wheel output shaft 16 and the connecting shaft 26 are shifted in the vehicle width direction, and for convenience of drawing, the connecting shaft 26 and the transmission gear 27 are indicated by broken lines in FIG.

  A motor case 29 is attached to the rear side of the gear case 17 in the vehicle, and the drive motor 11 is incorporated in the motor case 29. The drive motor 11 includes a rotor 11a and a stator 11b, and the stator 11b is fixed to a motor case 29 so as to surround the rotor 11a. The motor drive shaft 11c fixed to the rotor 11a protrudes from both ends of the rotor 11a, and one end of the motor drive shaft 11c is splined to the connecting shaft 26. Thus, the motor drive shaft 11c is connected to the front wheel output shaft 16, and by driving the drive motor 11, not only engine power but also motor power can be transmitted to the front wheel output shaft 16. .

  A transfer case 30 is attached to the rear side of the motor case 29 and a transfer mechanism 31 for transmitting power to the rear wheels is incorporated in the transfer case 30. The transfer mechanism 31 includes a transfer input shaft 32 that is spline-coupled to the other end of the motor drive shaft 11c, and a transfer output shaft 33 that is arranged in parallel thereto. The transfer input shaft 32 and the transfer output shaft 33 are engaged with each other via a gear train 34, and power from the motor drive shaft 11 c is transmitted to the transfer output shaft 33.

  An electronically controlled coupling 35 serving as a torque distribution mechanism is connected to the transfer output shaft 33 protruding from the transfer case 30. The coupling 35 is an electromagnetic clutch that is switched to the engaged state by exciting the electromagnetic coil 35a and switched to the disconnected state by releasing the excitation. Further, a joint 36 is splined to the coupling 35, and a propeller shaft for driving a rear differential mechanism (not shown) is connected to the joint 36.

  By exciting the electromagnetic coil 35a and switching the coupling 35 to the engaged state, power can be transmitted not only to the front wheels but also to the rear wheels. In addition, since the fastening force of the coupling 35 can be controlled according to the magnitude of the energization current to the electromagnetic coil 35a, the torque distribution ratio between the front and rear wheels is set to 100: 0 to 50:50 according to the traveling state of the vehicle. Can be set within the range.

  In order to drive and control the drive motor 11, a battery 38 is connected to the drive motor 11 via an inverter 37. The direct current from the battery 38 is converted into an alternating current by the inverter 37 and then supplied to the stator coil 11 d of the drive motor 11. The inverter 37 can control the drive state of the drive motor 11 according to the traveling state by adjusting the frequency and voltage of the power supplied to the stator coil 11d. The stator coil 12 c of the generator 12 is also connected to the battery 38 via the inverter 37, and the generated alternating current is converted into a direct current by the inverter 37 and charged to the battery 38. Furthermore, since electric power can be supplied to the generator 12 via the inverter 37, the generator 12 can also be operated as a starter motor. A battery 38 is connected to the various electrical components 39 via a DC / DC converter 40, and the power supplied to the various electrical components 39 is a predetermined voltage (for example, 12V) by the DC / DC converter 40. Is converted to

  This hybrid vehicle uses an engine 10 and a drive motor 11 as power sources, and according to the traveling state of the vehicle, a motor travel mode in which the vehicle is driven only by the drive motor 11 and an engine travel mode in which the vehicle is driven only by the engine 10. The vehicle can be selectively switched to the parallel traveling mode in which the vehicle is driven using both powers. For example, the vehicle is driven in the motor travel mode using the drive motor 11 at the time of start where the drive torque is required, and the vehicle is driven in the engine travel mode using the engine 10 as the vehicle speed increases. At high loads such as when accelerating during high-speed traveling, the vehicle is driven in a parallel traveling mode in which the drive motor 11 and the engine 10 are used together. On the other hand, during low-load traveling, power can be generated by the generator 12 using engine power as a power source, and the generated power energy can be charged in the battery 38. The crankshaft 10a can be rotated by operating the generator 12 as a drive source when the engine 10 is started, and the battery 38 is charged with regenerated electric power by operating the drive motor 11 as a generator during braking. Can do.

  Since the motor drive shaft 11c is directly connected to the front wheel output shaft 16 by the transmission gears 27 and 28, when engine power is transmitted to the front wheel output shaft 16, the engine power is also transmitted to the motor drive shaft 11c. Since the motor drive shaft 11c is connected to the transfer output shaft 33, the engine power is transmitted to the transfer output shaft 33 via the motor drive shaft 11c, and a differential gear mechanism for the propeller shaft and rear wheels (not shown) is provided. Engine power is transmitted to the rear wheels. Since the drive motor 11 is mounted on the motor drive shaft 11c, the motor power can be directly transmitted to the motor drive shaft 11c, and only the motor power or engine power can be added to the motor drive shaft 11c and transmitted to the rear wheels.

  FIG. 2 is a block diagram showing a control circuit of the hybrid vehicle shown in FIG. 1. The control unit 41 as a motor output control means has a vehicle speed sensor 42 for detecting the vehicle speed, and determines whether or not the vehicle is ready for running. Ignition sensor 43, accelerator sensor 44 as accelerator detecting means for detecting the operation of the accelerator, brake sensor 45 as brake detecting means for detecting the operation of the brake, and the motor output of the drive motor 11 based on the output current value. A detection signal is input from a motor output sensor 46 or other sensors as motor output detection means. The operation of the accelerator is detected, for example, by measuring the depression amount of the accelerator pedal 47 and the accelerator opening, and the operation of the brake is, for example, measuring the hydraulic pressure in the master cylinder generated according to the depression amount of the brake pedal 48, for example. Detected by.

  A control signal is sent from the control unit 41 to the engine 10, the drive motor 11, the generator 12, the clutch mechanism 18, the synchronous switching mechanism 23, the inverter 37, and other devices. The control unit 41 includes a microprocessor that calculates control signals, a ROM that stores control programs, arithmetic expressions, map data, and the like, and a RAM that temporarily stores data.

  In such a hybrid vehicle, as described above, it is possible to travel in various travel modes, but in the state where the clutch mechanism 18 is switched to the power shut-off state, particularly between the start state and the medium speed range. It is preferable that the engine 10 is run in the motor running mode while generating power by performing rated operation in an efficient region. Here, when the vehicle is started in the motor drive mode, the necessary and sufficient driving force for starting is ensured in situations where a stall is likely to occur, such as when the driver intentionally starts a stall or starts a slope. However, it is necessary to effectively protect the drive motor 11 and suppress the waste of the battery 38.

  FIG. 3 is a flowchart showing a motor output restriction processing procedure in the hybrid vehicle control device of the present invention. The output restriction procedure of the drive motor 11 during a stall will be described with reference to FIG.

  The output limitation of the drive motor 11 is executed when the ignition is in the ON state, that is, the Ready state, the accelerator and the brake are both in the ON state, and the motor output is equal to or higher than the set value. First, in step S1, it is determined by the ignition sensor 43 whether or not it is in a ready state based on an output signal from the ignition sensor 43. Subsequently, in step S2, it is determined whether or not the accelerator is in an ON state, and in step S3 whether or not the brake is in an ON state. Here, the case where it is determined that the accelerator is in the ON state is a case where, for example, the accelerator sensor 44 detects that the amount of depression of the accelerator pedal 47 is greater than or equal to a set value, and the brake is in the ON state. The case where it is determined to be a case is, for example, a case where the brake sensor 45 detects that the amount of depression of the brake pedal 48 is greater than or equal to a set value.

  If it is determined in step S4 that the motor output detected by the motor output sensor 46 is greater than or equal to the set value, then in step S5, the current value supplied to the drive motor 11 is reduced based on a predetermined motor output reduction rate. As a result, the motor output is gradually reduced. Thereby, it is possible to reduce the waste of the battery 38 and protect the drive motor, the inverter, and the like while securing a necessary and sufficient driving force.

  This motor output reduction rate can also be set according to the vehicle speed. FIG. 4 is a flowchart showing another embodiment of the motor output restriction processing procedure in the hybrid vehicle control apparatus of the present invention. Each process of step S1-step S4 shown by FIG. 4 is the same as each process of step S1-step S4 shown by FIG. 3, and abbreviate | omits description.

  In step S5 to step S7, the output restriction delay time T when the vehicle speed detected by the vehicle speed sensor 42 is equal to or higher than the set value is greater than that when the vehicle speed is less than the set value, T1 (> T2). The process of setting to is performed. That is, the motor output decrease rate when the vehicle speed is equal to or higher than the set value is set to be larger than when the vehicle speed is less than the set value. In step S8, the motor output is limited based on the output limit delay time T set in steps S5 to S7. As a result, for example, when a vehicle traveling at a predetermined speed or more falls into a stalled state, a reduction in battery waste and protection of the drive motor, inverter, etc. are performed quickly by setting a large motor output reduction rate. be able to.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, FIG. 1 discloses a series / parallel hybrid vehicle, but the present invention may be applied to a series or parallel hybrid vehicle. Stalls can also occur when the parking brake is operating or when the wheel enters the groove, but the present invention can also be applied to these cases.

FIG. 1 is a skeleton diagram showing an embodiment of a hybrid vehicle to which the present invention is applied. It is a block diagram which shows the control circuit of the hybrid vehicle shown in FIG. It is a flowchart which shows the motor output restriction | limiting process procedure in the control apparatus of the hybrid vehicle of this invention. It is a flowchart which shows other embodiment of the motor output restriction | limiting process procedure in the control apparatus of the hybrid vehicle of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 10a Crankshaft 11 Drive motor 11c Motor drive shaft 12 Generator 15 Transmission input shaft 16 Front wheel output shaft 18 Clutch mechanism 23 Synchronous switching mechanism 31 Transfer mechanism 35 Coupling 47 Accelerator pedal 48 Brake pedal

Claims (3)

A generator driven by an engine, a drive motor driven using electric power from the generator, and a clutch mechanism for switching between a power transmission state in which engine power is transmitted to drive wheels and a power cutoff state in which the engine power is not transmitted A control device for a hybrid vehicle,
An accelerator detection means for detecting the operation of the accelerator;
Brake detection means for detecting the operation of the brake;
Motor output detection means for detecting the motor output of the drive motor;
A motor output limiting means for gradually reducing the motor output based on a predetermined motor output reduction rate when the operation of the accelerator and the brake is detected and the detected value by the motor output detecting means is a set value or more; A control device for a hybrid vehicle, comprising:   2. The control apparatus for a hybrid vehicle according to claim 1, wherein the motor output limiting means is executed under a state in which the clutch mechanism is switched to a power cut-off state. 3. The hybrid vehicle control device according to claim 1, further comprising a vehicle speed detection unit that detects a vehicle speed, wherein the motor output reduction rate when the detection value by the vehicle speed detection unit is equal to or greater than a set value is less than the set value. A control device for a hybrid vehicle, wherein the control device is set larger than a certain case.

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