JP6374803B2 - Hybrid car - Google Patents

Description

  The present invention relates to a hybrid vehicle having two power sources of an engine and a motor.

Currently, hybrid vehicles having two power sources, an engine and a motor, are in widespread use. In such a hybrid vehicle, when the remaining battery level is sufficient, the motor driving mode runs with the motor in preference to the engine, and when the remaining battery level is low, the engine combined mode runs using both the motor and the engine. The driving mode is prepared. For example, in a hybrid vehicle, when the traveling mode is selected according to the remaining battery level and the engine combined mode is selected, the driving state between the engine and the motor is switched according to the traveling state, thereby increasing energy efficiency. At the same time, exhaust gas such as CO ₂ can be reduced.

  A plug-in hybrid vehicle (PHEV) that can directly charge electric energy used in such a hybrid vehicle from a commercial outlet has also been proposed. Such a plug-in hybrid vehicle generally has a larger battery capacity than a non-plug-in hybrid vehicle, and can travel a long distance in the motor travel mode.

  In addition, in a vehicle such as a plug-in hybrid vehicle, any driving state of 4WD (four-wheel drive) driving that drives the front and rear wheels and 2WD (two-wheel drive) driving that drives either the front wheels or the rear wheels is possible. According to the traveling state, 4WD traveling and 2WD traveling can be switched (part time 4WD, etc.). At this time, for example, a technique is disclosed in which an automobile always travels 4WD and switches from 4WD travel to 2WD travel when the vehicle is turning sharply (for example, Patent Document 1). Also disclosed is a technique for switching to 4WD traveling when slip occurs during 2WD traveling, and returning to 2WD traveling when accelerating or leaving a steady traveling region (for example, Patent Document 2). If the speed change is small and the difference in speed between the left and right wheels is small during 4WD traveling, it switches to 2WD traveling. If the speed change is small and the speed difference between the left and right wheels increases, it returns to 4WD traveling. A technique to be disclosed is also disclosed (Patent Document 3).

  In addition, when switching between 4WD traveling and 2WD traveling is realized using electronically controlled coupling, driving power is always consumed by electronically controlled coupling while traveling 4WD. Therefore, a technique is disclosed in which power consumption is reduced by supplying drive power to the electronic control coupling in a time-sharing (duty) manner during 4WD travel (for example, Patent Document 4). Also disclosed is a technique in which the region operated by 4WD driving is reduced when the EV switch is on compared to when the EV switch is off (eg, Patent Document 5).

Japanese Patent Publication No. 5-37854 Japanese Patent Publication No.62-8334 Japanese Patent No. 3582375 Japanese Patent Laid-Open No. 2002-225583 Japanese Patent No. 4225314

  In a hybrid vehicle that travels by switching between 2WD traveling and 4WD traveling as described above, if a large driving force is applied during 2WD traveling, a load is applied only to the driving wheels involved in 2WD traveling, and the components of the drive system ( For example, there is a risk of damage to a differential gear or a drive shaft. Therefore, it is conceivable to constantly drive 4WD to disperse the driving force and prevent damage to the components of the driving system.

  However, as described above, the driving power is always consumed by the electronically controlled coupling during the 4WD traveling. In particular, the hybrid vehicle and the plug-in hybrid vehicle can be used for traveling due to the battery consumption. As a result, the electric power is reduced and the mileage is affected.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a hybrid vehicle that can reduce power consumption while avoiding damage to components of a drive train.

  In order to solve the above-described problems, a hybrid vehicle according to the present invention includes a transmission that transmits a driving force of one or both of an engine and a motor to one of a front wheel and a rear wheel, and a driving force output from the transmission. Derivation of driving force in an electronically controlled coupling that transmits to one of the rear wheels, a driving force deriving unit that derives the driving force requested by the driver, and a motor traveling mode in which the motor runs in preference to the engine If the driving force derived by the driving unit is greater than or equal to the threshold value, the driving mode switching unit that starts the engine and in the motor driving mode, if the driving force derived by the driving force deriving unit is less than the threshold value, 2WD traveling is performed. If the driving force derived by the deriving unit is greater than or equal to the threshold value, the drive switching unit that performs 4WD traveling, and the electronic control cup while the 4WD traveling is performed Characterized in that it comprises a coupling control unit for driving the ring, the.

  The travel mode switching unit may stop the engine when the driving force is less than the threshold value and a predetermined stop condition is satisfied in the motor travel mode.

  According to the present invention, it is possible to reduce power consumption while avoiding damage to components of a drive system.

It is a figure which shows the structure of a hybrid vehicle. It is a flowchart for demonstrating the driving | running | working process by a control part.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a diagram showing a configuration of the hybrid vehicle 100. The hybrid vehicle 100 is capable of any driving state of 4WD (four-wheel drive) traveling that drives front and rear wheels and 2WD (two-wheel drive) traveling that drives only the front wheels, and includes an engine 110, a fuel tank 112, a clutch 114, Transmission 116, electronic control unit (hereinafter simply referred to as ECU) 118, motor 120, inverter 122, battery 124, propeller shaft 126, front differential gear 128, front drive shaft 130, front wheel 132, electronic control coupling 134, rear differential It includes a gear 136, a rear drive shaft 138, a rear wheel 140, a control unit 142, and an accelerator pedal sensor 144.

  In this embodiment, a plug-in hybrid vehicle (PHEV) capable of directly charging electric energy from a commercial outlet will be described as the hybrid vehicle 100. Here, the configuration related to the feature of the present embodiment will be described in detail, and the description of the configuration unrelated to the feature of the present embodiment will be omitted.

  The engine 110 is composed of a gasoline engine or a diesel engine, and obtains driving force by burning fuel (gasoline, diesel, etc.) supplied from a fuel tank 112, and the obtained driving force is transmitted via the clutch 114. It is transmitted to the transmission 116. Engine 110 is connected to ECU 118, and the driving force is adjusted based on a control command from ECU 118.

  The motor 120 is arranged coaxially with the engine 110, obtains a driving force by the electric power supplied from the battery 124 via the inverter 122, and transmits the obtained driving force to the transmission 116. The motor 120 also functions as a generator at a timing when no power is supplied, and the generated power is stored in the battery 124 via the inverter 122. Inverter 122 is connected to ECU 118, and the supplied power (driving force of motor 120) is adjusted based on a control command from ECU 118.

  The driving force obtained by the engine 110 and the motor 120 is transmitted to the propeller shaft 126 after adjusting the torque, the number of rotations, and the rotation direction by the transmission 116, and is further transmitted to the front wheel 132 via the front differential gear 128 and the front drive shaft 130. Is transmitted to. Further, during 4WD traveling, the driving force output from the transmission 116 is transmitted to the rear wheel 140 via the electronic control coupling 134, the rear differential gear 136, and the rear drive shaft 138. Here, the front wheel 132 obtains a driving force directly from the transmission 116 and the rear wheel 140 obtains a driving force via the electronic control coupling 134, but the driving force is directly applied to the rear wheel 140 from the transmission 116. The driving force may be transmitted to the front wheel 132 via the electronic control coupling 134.

  The control unit 142 is configured by a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing programs, a RAM as a work area, and the like, and performs overall control of the entire hybrid vehicle 100. In the present embodiment, the control unit 142 also functions as a travel mode switching unit 150, a driving force deriving unit 152, a drive switching unit 154, and a coupling control unit 156. Each sensor such as an accelerator pedal sensor 144 that detects a depression amount of an accelerator pedal (not shown) is connected to the control unit 142, and the control unit 142 takes in a detection signal of each sensor. Further, the control unit 142 controls the driving force of the engine 110 and the motor 120 via the ECU 118.

(Driving mode switching)
In the hybrid vehicle 100, as a travel mode, a motor travel mode in which the motor 120 travels with priority over the engine 110 when the remaining amount of the battery 124 is sufficient, and a case where the remaining amount of the battery 124 is small (for example, the motor travel mode). Thus, after the remaining amount of the battery 124 is reduced, an engine combined mode in which the motor 120 and the engine 110 are used together is prepared. Then, traveling mode switching unit 150 switches the traveling mode according to the traveling state at that time. However, in the present embodiment, as will be described later, the engine 110 may be temporarily started in the motor travel mode.

  In the case of the plug-in hybrid vehicle as in the present embodiment, the battery 124 is charged with power from a commercial outlet in advance using nighttime power or the like, and is consumed from the charged power when traveling. Therefore, traveling mode switching unit 150 selects the motor traveling mode when traveling starts. A plug-in hybrid vehicle generally has a larger capacity of the battery 124 than a non-plug-in hybrid vehicle, and thus can travel a long distance in a motor travel mode. At this time, traveling mode switching unit 150 avoids engine 110 from becoming a rotational load by disengaging clutch 114. In any driving mode, when the brake is stepped on or the accelerator is released, the motor 120 is used as a generator, and regenerative energy is recovered.

  Then, when the remaining amount of battery 124 decreases, traveling mode switching unit 150 maintains the traveling by switching the traveling mode from the motor traveling mode to the engine combined mode. In such an engine combined mode, since the driving force of either the engine 110 or the motor 120 can be used, smooth and powerful traveling is possible as compared with the case where the engine 110 operates alone. Further, the engine 110 is difficult to obtain a large torque in a low rotation range, but the motor 120 is driven with priority in such a low rotation range. Thus, the response is improved, and the vehicle can be started smoothly and efficiently. Further, when the remaining amount of battery 124 falls below a predetermined value, traveling mode switching unit 150 causes motor 120 to function as a generator and accumulates electric power in battery 124 by the driving force of engine 110.

(Operation of control unit 142)
Further, the hybrid vehicle 100 can be set so that it can travel by switching between 2WD traveling and 4WD traveling. However, if a large driving force is applied during 2WD travel (when requested), a load is applied only to the drive wheels involved in the 2WD travel, which may cause damage to the components of the drive system. On the other hand, if 4WD traveling is always performed in order to disperse the driving force, the driving power is always consumed by the electronic control coupling 134 during the traveling, and the power available for traveling is consumed by the consumption of the battery 124. Decreases and affects mileage. Therefore, by efficiently switching between 2WD traveling and 4WD traveling, power consumption is reduced while avoiding damage to the components of the drive system.

  The driving force deriving unit 152 acquires the amount of depression of the accelerator pedal detected by the accelerator pedal sensor 144 and derives the driving force requested by the driver.

  When the current driving mode is the motor driving mode, the driving mode switching unit 150 forcibly maintains the motor driving mode if the driving force derived by the driving force deriving unit 152 is equal to or greater than a predetermined threshold. The engine 110 is started. Thus, by starting the engine 110, in addition to the motor 120, the driving force of the engine 110 can be obtained, and the driver's request for driving force can be met. Such a threshold value can be set to an arbitrary value according to an experiment or actual driving.

  Here, during the motor travel mode, the engine 110 is started when the driving force derived by the driving force deriving unit 152 is equal to or greater than a predetermined threshold, but even if the driving force is less than the predetermined threshold. The engine 110 is not stopped immediately. This is because the fuel consumption of the engine 110 is improved by maintaining the driving state of the engine 110 for a certain period of time rather than repeating the start and stop of the engine 110 within a short time. Therefore, travel mode switching unit 150 stops engine 110 only when the driving force is less than the threshold value and a predetermined stop condition is satisfied (hysteresis characteristic). Here, as the predetermined stop condition, for example, the time after the engine 110 is started has exceeded a predetermined time, the temperature of the engine 110 satisfies a predetermined temperature condition, and the remaining amount of the battery 124 is a predetermined value. The above may be considered.

  The drive switching unit 154 can switch between 2WD traveling and 4WD traveling. When the traveling mode at that time is the motor traveling mode, if the driving force derived by the driving force deriving unit 152 is less than a predetermined threshold value. 2WD traveling is performed, and if the driving force derived by the driving force deriving unit 152 is equal to or greater than a predetermined threshold, 4WD traveling is performed. Therefore, if the driving force derived by driving force deriving unit 152 is equal to or greater than a predetermined threshold value, engine 110 can be started at least in a state in which it has shifted to 4WD traveling. However, it is desirable that the execution order of the switching process to 4WD traveling and the starting process of the engine 110 is performed in advance of the switching process to 4WD traveling from the viewpoint of component protection. Further, when the traveling mode is the engine combined mode, the drive switching unit 154 maintains 4WD traveling as the driving state of the engine 110 is maintained.

  The coupling control unit 156 drives the drive solenoid of the electronically controlled coupling 134 during the 4WD traveling, and adjusts the duty of the front wheel 132 and the rear wheel 140 according to the traveling state to the rear wheel 140. Performs optimal driving force transmission.

  FIG. 2 is a flowchart for explaining the travel processing by the control unit 142. First, it is determined whether or not the current travel mode is the motor travel mode (S200). If the current travel mode is the motor travel mode (YES in S200), the driving force deriving unit 152 determines the driving force requested by the driver. Derived (S202), if it is not the motor travel mode (NO in S200), the travel processing is terminated.

  Then, when the driving force requested by the driver is derived, it is determined whether or not the derived driving force is equal to or greater than a predetermined threshold (S204), and when it is determined to be equal to or greater than the predetermined threshold ( The following processing is executed in step S204.

  That is, the drive switching unit 154 determines whether or not the current drive state is 4WD travel (S206), and if it is not 4WD travel (NO in S206), it switches to 4WD travel (S208). At this time, the coupling control unit 156 drives the electronic control coupling 134 to transmit the optimum driving force to the rear wheels 140 according to the traveling state. If the current driving state is 4WD traveling (YES in S206), the 4WD traveling is maintained. Subsequently, traveling mode switching unit 150 determines whether or not engine 110 is currently in a driving state (S210). If engine 110 is not in a driving state (NO in S210), engine 110 is started (S212). If engine 110 is already in a driving state (YES in S210), the driving state of engine 110 is maintained.

  If the driving force derived by the driving force deriving unit 152 is less than the predetermined threshold (NO in S204), the following processing is executed.

  That is, the drive switching unit 154 determines whether or not the current drive state is 2WD travel (S220), and if it is not 2WD travel (NO in S220), it switches to 2WD travel (S222). At this time, the coupling control unit 156 stops driving the electronic control coupling 134. If the current driving state is 2WD traveling (YES in S220), the 2WD traveling is maintained. Subsequently, the travel mode switching unit 150 determines whether or not the engine 110 is currently in a driving state and satisfies a predetermined stop condition (S224), and the engine 110 is in a driving state and has a predetermined stop condition. Is satisfied (YES in S224), the engine 110 is stopped (S226), and the engine 110 is already stopped or is in a driving state but does not satisfy a predetermined stop condition (NO in S224). The state (drive or stop) of engine 110 is maintained.

  As described above, in the hybrid vehicle 100 of the present embodiment, when the driving force requested by the driver is high, the engine 110 is started and the request is met, and the power consumption of the motor 120 is not increased unnecessarily. Therefore, it is possible to suppress power consumption used for traveling. Also, when the driving force required by the driver is high, switching to 4WD traveling can disperse the required high driving force, thereby avoiding damage to the components of the drive system (component protection). . Further, by maintaining the 2WD traveling while the driving force required by the driver is low, it is not necessary to drive the electronic control coupling 134, so that the power consumption can be reduced accordingly. In short, the combined use of the engine 110 provides a high driving force, and the power consumption can be reduced by the 2WD traveling while avoiding damage to the components of the driving system by the 4WD traveling.

  Further, if the time occupancy ratio of 4WD traveling in the entire traveling can be increased within the range allowed by power consumption, that is, if the predetermined threshold value can be decreased, the driving power required by the driver is switched to the 4WD traveling from the low level. Therefore, it is not necessary to increase the durability with respect to the driving force of the hybrid vehicle 100 itself, and the manufacturing cost can be reduced.

  Also provided are a program that causes a computer to function as the control unit 142, and a storage medium such as a computer-readable flexible disk, magneto-optical disk, ROM, CD, DVD, or BD on which the program is recorded. Here, the program refers to data processing means described in an arbitrary language or description method.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  Note that each step of the traveling process of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processes in parallel or by a subroutine.

  The present invention can be used for a hybrid vehicle having two power sources of an engine and a motor.

DESCRIPTION OF SYMBOLS 100 Hybrid vehicle 110 Engine 116 Transmission 120 Motor 134 Electronically controlled coupling 150 Traveling mode switching part 152 Driving force deriving part 154 Driving switching part

Claims (2)

A transmission for transmitting the driving force of one or both of the engine and the motor to one of the front wheels and the rear wheels;
An electronically controlled coupling that transmits the driving force output from the transmission to one of the front wheel and the rear wheel;
A driving force deriving unit for deriving the driving force requested by the driver;
In a motor travel mode in which the motor travels preferentially over the engine, if the driving force derived by the driving force deriving unit is greater than or equal to a threshold value, a traveling mode switching unit that starts the engine;
In the motor travel mode, if the driving force derived by the driving force deriving unit is less than the threshold, 2WD traveling is performed, and if the driving force derived by the driving force deriving unit is equal to or greater than the threshold, 4WD traveling is performed. A switching unit;
A coupling control unit that drives the electronically controlled coupling while the 4WD traveling is performed;
A hybrid vehicle comprising:   2. The hybrid vehicle according to claim 1, wherein the driving mode switching unit stops the engine when the driving force is less than the threshold and a predetermined stop condition is satisfied in the motor driving mode. .

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