JPH06319206A - Brake control device of hybrid automobile - Google Patents

Abstract

PURPOSE:To prevent the stopped state of an internal combustion engine for a long time with respect to the brake control device of a hybrid automobile, wherein an engine brake and regenerative braking are combined in the hybrid automobile and the proper braking characteristic is secured. CONSTITUTION:An internal combustion engine 11 is linked to a speed change gear 15 through an engine clutch 13. A motor 12 is linked to the speed change gear 15 through a motor clutch 14. A brake computer 12 connects the engine clutch 13 or the motor clutch 14 in response to the driver's request so as to use the internal combustion engine 11 or the motor 12 as the power source. When the automobile is running with the motor 12 as the power source, the engine clutch 13 is connected when an access pedal is fully closed (idle switch 17 is ON) and the braking operation is performed (a brake switch 16 is ON), and the internal combustion engine 11 is forcibly operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking control device for a hybrid vehicle, and more particularly, in a hybrid vehicle,
The present invention relates to a braking control device for a hybrid vehicle that ensures appropriate braking characteristics by appropriately combining regenerative braking with an electric motor, engine braking with an internal combustion engine, and friction braking with a braking mechanism.

[0002]

2. Description of the Related Art Conventionally, a hybrid vehicle having an internal combustion engine and an electric motor as a power source has been known. For example, Japanese Patent Application Laid-Open No. 59-204402 discloses a hybrid vehicle in which the exhaust gas emission amount is reduced and the fuel consumption is improved by appropriately operating the internal combustion engine and the electric motor.

This hybrid vehicle is equipped with a connecting member for properly connecting or disconnecting the axle connected to the drive wheels and the output shaft of the internal combustion engine or the output shaft of the electric motor. Either the output shaft of the internal combustion engine or the output shaft of the electric motor. Only one of them can be connected to the axle.

Therefore, when the driving force is obtained from the internal combustion engine under a predetermined condition, the electric motor is not unnecessarily rotated, and conversely, when the driving force is obtained from the electric motor, the internal combustion engine is not idled. . Therefore, the driving force generated by each power source is not wasted,
The operating efficiencies of the internal combustion engine and the electric motor mounted can be maintained at the same level as in the case where each of them is mounted alone.

As a result, if a region in which the driving force can be generated more efficiently is set in accordance with the driving condition of the vehicle and the electric motor and the internal combustion engine are appropriately switched, they can be mounted independently on the vehicle. Compared with the above, it is possible to obtain higher driving efficiency, which is superior in terms of environmental protection, and it is also possible to improve fuel efficiency.

By the way, as a usage pattern of such a hybrid vehicle, a large number of vehicles are concentrated, and in an urban area where photochemical smog is a problem, it can be efficiently driven as an electric vehicle with little traffic. In the suburbs, the form of use as an internal combustion engine type automobile is considered to be promising.

In other words, in the future, when a law regulation for the purpose of regulating the use of the internal combustion engine type automobile in the urban area is enforced, as a means for satisfying the regulation in the urban area and ensuring the traveling efficiency in the suburbs, Hybridization of vehicles is an extremely effective means.

[0008]

However, when the above-mentioned conventional hybrid vehicle continues to be used in urban areas for a long period of time under such usage pattern, the internal combustion engine mounted on the hybrid vehicle continues to be used during that period. It will be kept stopped. Such a situation is not a favorable state for the internal combustion engine, and its influence appears as deterioration of startability.

That is, if the internal combustion engine is maintained in a stopped state for a long period of time, it causes rust inside the internal combustion engine due to, for example, the lubricating oil not being stirred. Further, similarly, the effect of oil supply to the seal member and the like is cut off, and the deterioration thereof is promoted, which causes deterioration of the sealing property of each portion.

Further, in a carburettor-equipped vehicle, since the heavy fuel with poor vaporization remains due to the evaporation of the light fuel in the carburettor and the fuel oil level is lowered, the startability thereof is remarkable. It will get worse. Further, in a diesel engine that uses light oil as a fuel, the fuel pump and the like may be damaged due to the oxidation of the light oil after being left for a long time.

As described above, in the above-described conventional hybrid vehicle, the internal combustion engine mounted therein may be kept in a stopped state for a long period of time, which may cause various problems. Had.

The present invention has been made in view of the above points, and when the hybrid vehicle is running with the electric motor as the power source, the internal combustion engine is forcibly operated during braking of the hybrid vehicle. An object of the present invention is to provide a braking control device for a hybrid vehicle that can solve the problems.

[0013]

The above object is to provide an internal combustion engine 1 and an electric motor 2 as power sources, as shown in the principle configuration diagram of FIG. 1, and to provide an output shaft of the internal combustion engine 1 and an axle of drive wheels. A braking control device for a hybrid vehicle, which comprises a connecting means 4 for controlling the connection with the hybrid vehicle 3, and controls the braking characteristics of the hybrid vehicle in which the driving force required for traveling is appropriately generated by the internal combustion engine 1 and the electric motor 2. An accelerator operation amount detecting means 5 for detecting an operation amount of an accelerator operating member used for operating the driving force generated by the power sources 1 and 2, a vehicle traveling state detecting means 6 for detecting a traveling state of the vehicle, and the accelerator operation. A connection control means 7 for connecting the connecting means 4 when the detection value of the quantity detecting means 5 is less than or equal to a predetermined value and the vehicle traveling state detecting means 6 detects a predetermined traveling state. It is achieved by the braking control device of the lid automobile.

[0014]

In the hybrid vehicle braking control apparatus according to the present invention, the accelerator operation amount detecting means 5 represents the driver's request for the vehicle. That is, when the driver attempts to accelerate the vehicle, the detected value becomes large, and when the driver tries to decelerate, the value becomes small.

Therefore, the connection control means 7 determines that the running state of the vehicle detected based on the detection value of the vehicle running state detecting means 6 is a predetermined state, and the driver decelerates from that state to a predetermined level. The connection means 4 when it is desired to request
Acts to connect. As a result, the internal combustion engine 1
The output shaft of 1 is forcibly rotated by the axle 3, braking force by engine braking is generated in the vehicle, and the lubricating oil is stirred in the internal combustion engine 1.

That is, when the vehicle is traveling with the electric motor 2 as a power source, the internal combustion engine 1 appropriately functions as a mechanism that exerts a braking force. Therefore, the mechanical elements forming the internal combustion engine 1 will not be stopped for a long period of time.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 shows a conceptual diagram of the structure of a hybrid vehicle equipped with an embodiment of a braking control device according to the present invention. In the figure, reference numerals 11 and 12 denote an internal combustion engine and an electric motor which are power sources of the hybrid vehicle.

The internal combustion engine 11 and the electric motor 12 are connected to a transmission 15 via an engine clutch 13 and an electric motor clutch 14, respectively. Engine clutch 1
The 3 and the electric motor clutch 14 control the connection between the internal combustion engine 11 or the electric motor 12 and the transmission 15 in accordance with a control signal from the outside.

An axle connected to drive wheels (not shown) of the hybrid vehicle is connected to the transmission 15, and the rotation of the engine clutch 13 or the electric motor clutch 14 is transmitted to the axle at a desired reduction ratio. The transmission 15 in the present embodiment is an electronically controlled automatic transmission, and it is possible to perform an appropriate shift up / down by supplying an appropriate shift signal from the outside.

Further, in FIG. 2, reference numeral 16 indicates a brake switch. The brake switch 16 is a switch that outputs an output signal in conjunction with the operation of a brake pedal (not shown), and outputs an ON signal when the driver performs a brake operation. The idle switch 17 is a switch that outputs an output signal in conjunction with the operation of an accelerator pedal (not shown), and outputs an ON signal when the accelerator pedal is not depressed.

The vehicle speed sensor 18 is a sensor that emits a pulse signal corresponding to the rotational speed of a wheel (not shown) as a signal representing the vehicle speed. In this embodiment, the vehicle speed is detected based on the cycle of the pulse signal.

The control computer 20 includes the brake switch 16, the idle switch 17, and the vehicle speed sensor 18.
Also, various detection signals are supplied from various sensors installed in the internal combustion engine 11, etc., and based on these signals, the accelerator operation amount detection means 5, the vehicle running state detection means 6,
This is a main part of the present embodiment that executes the processing described below to realize the connection control means 7.

The hardware configuration of the control computer 20 for controlling the operation of this embodiment will be described below in detail with reference to FIG. In FIG. 3, the same components as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 3, the control computer 20
Is a central processing unit (CPU) 21, a read only memory (ROM) 22 storing a processing program, and a random access memory (RA) used as a work area.
M) 23, which are connected to each other via a bidirectional bus line 24, and are connected to the input / output port 25, the input port 26, and the output ports 27 to 33, respectively.

Further, the control computer 20 uses the buffer 3
The water temperature sensor 11a for detecting the cooling water temperature of the internal combustion engine 11 and the intake air temperature sensor 11b for detecting the intake air temperature are connected via 4, 35. Further, the buffer 36 is provided with a sensor 15a for detecting the shift state of the transmission 15 described above.
The buffer 37 is connected to the sensor 12a that detects the rotation speed of the electric motor 12 described above.

These water temperature sensor 11a and intake air temperature sensor 1
The detection signals of 1b, the transmission sensor 15a, and the electric motor sensor 12a are sequentially selected by the multiplexer 38, output to the A / D converter 39, converted into digital signals, and then transferred to the bus line 24 via the input / output port 25. It is configured to be sent out.

The output signals of the brake switch 16, the idle switch 17, the vehicle speed sensor 18 and the output signals of the crank sensors 11c, which generate pulse signals in response to the rotation of the crankshaft of the internal combustion engine 11, are waveform shaping circuits. After being shaped into an appropriate pulse waveform at 40, it is input to the input port 26.

Further, the control computer 20 includes the drive circuit 4
1 to 47, and drives various actuators and the like according to signals supplied from the output ports 27 to 33. That is, the output signal of the output port 27 is the drive circuit 41.
Injector 11d disposed in the internal combustion engine 11 via the
Is supplied to.

The output signal of the output port 28 is supplied to the igniter 11e arranged in the internal combustion engine 11 via the drive circuit 42. Here, the injector 1 described above
1d is a fuel injection valve for injecting desired fuel into the internal combustion engine 11, and the igniter 11e is an appropriate ignition signal for an ignition plug (not shown) arranged in each cylinder of the internal combustion engine 11. Is a device for supplying.

The signal from the output port 29 is supplied to the drive circuit 43.
The signal from the output port 30 is supplied to the engine clutch 13 via the drive circuit 44 and to the electric motor clutch 14 via the drive circuit 44. Then, the output signal from the output port 31 is supplied to the control terminal 15b of the transmission 15 via the drive circuit 45. That is, the transmission 15 has the control terminal 15b.
The speed will be changed according to the signal supplied to.

The output port 32 is also connected via a drive circuit 46 to an ignition switch (IG switch) 11f which is a start / stop control switch for the internal combustion engine 11. Further, the output port 33 is connected via a drive circuit 47 to a motor control terminal 12b described later.

Hereinafter, the operation of the present embodiment device will be described in detail with reference to the flowcharts (FIGS. 4 and 5) of the processing executed by the control computer 20 in the braking control device having the above-mentioned configuration.

The routine processing shown in FIGS. 4 and 5 is an interrupt routine which is started every predetermined time when the hybrid vehicle is traveling with the electric motor 12 as a power source. Therefore, when this routine is started, the internal combustion engine 1
It is premised that the No. 1 IG switch 11f is off, the engine clutch 13 is off, and the electric motor clutch 14 is on.

As shown in FIG. 4, when this routine is started, first, at step 100, it is judged by the accelerator operation by the driver whether the accelerator pedal is fully closed. Then, if the idle switch 17 linked to the accelerator pedal is on, it is determined that the accelerator pedal is fully closed, and if the idle switch 17 is off, it is determined that the driver depresses the accelerator pedal.

By the way, in this routine, when the hybrid vehicle is being driven by the electric motor 12, the internal combustion engine 11 is operated for a long time by appropriately operating the internal combustion engine 11.
The purpose is to prevent the maintenance of the machine. However, when the internal combustion engine 11 is forcibly operated, energy is lost due to engine braking.
Therefore, in the configuration in which the control is performed such that the engine clutch 13 is simply turned on periodically, extra energy required for forcibly operating the internal combustion engine 11 is required, which violates the demand for improving fuel efficiency and the like.

Therefore, in this embodiment, when the driver intends to decelerate, the intention is detected and the internal combustion engine 11 is forcibly operated when the vehicle is braked. The reason why the accelerator pedal is fully closed in step 100 is to detect the driver's intention to decelerate.

Therefore, if the accelerator pedal is not fully closed, that is, if the driver intends steady running or acceleration, this processing is terminated as it is, and the internal combustion engine 11 is closed only when the accelerator pedal is fully closed. In order to perform the forced operation, the process proceeds to step 102. Here, the above step 10
The processing of 0 corresponds to the accelerator operation amount detecting means 5 described above.

Next, at step 102, it is judged if the brake switch 16 is on. When the brake switch 16 is on, that is, when the brake pedal is depressed by the driver, it means that an aggressive braking force is required, and when the brake switch 16 is off, traveling by inertia is intended. This is because the magnitude of the braking force that can be determined and must be exerted naturally is different.

If the brake switch 16 is on, the brake flag Fb is set to "1" in step 104, and if the brake switch 16 is off, the brake flag Fb is set to "0" in step 106 and the process proceeds to step 108. .

In step 108, it is determined whether the vehicle is traveling at a speed of 80 km / h or more based on the vehicle speed signal supplied from the vehicle speed sensor 18. Hereinafter, from step 110 onward until step 1 is detected until the level corresponding to the current vehicle speed is detected.
14 to 50 km / h or more, 20 km / h or more, or 1
Determine whether it is 0 km / h or higher.

This is because the relationship between the magnitude of the braking force acting on the vehicle and the impact generated by the braking force is relative to the vehicle speed, and it is necessary to exert the braking force according to the vehicle speed.

That is, in the hybrid vehicle of this embodiment, the braking force can be generated by the engine braking by the internal combustion engine 11, the regenerative braking by the electric motor 12, and the friction braking by the braking mechanism installed for each wheel. . However, if these engine braking, regenerative braking, and friction braking are uniformly generated, it becomes difficult to finely adjust the braking force, and it is extremely difficult to handle in situations where a delicate braking force is required, such as when driving at low speed. There is a possibility that it will become a thing.

The processing of steps 108 to 114 is performed in consideration of the characteristics of the braking force, and the processing described later is executed so as to exert an appropriate braking force according to the vehicle speed of each level. When the vehicle speed is less than 10 km / h, the routine proceeds to step 116, where the engine clutch 13, the IG switch 11f, and the electric motor clutch 14 are all turned off to disconnect the wheels from the power source, and the braking force is exerted only by the brake mechanism. The configuration.

Therefore, when the vehicle speed is on the verge of stop, which is less than 10 km / h, the braking force can be operated at the driver's will without being affected by the internal combustion engine 11 and the electric motor 12. The riding comfort is not impaired due to the function of the device.

On the other hand, if it is determined in step 108 that the vehicle speed is 80 km / h or more, step 12
The process proceeds to 0 and the transmission 15 is switched to the 4th speed. This is because, because the vehicle speed is high, it is necessary to set the transmission 15 at a high speed in advance in order to prevent excessive engine braking when the engine clutch 13 is engaged in the following steps.

By the way, the electric motor 12 of this embodiment has a coil for generating a regenerative current on the side of the stator fixed to the housing, and the field current i is passed to the side of the rotor that rotates with the rotating shaft, so that the field current i is predetermined. It has a coil that generates a magnetic field. Therefore, when an appropriate field current i is made to flow through the coil on the rotor side when the vehicle is decelerated with the electric motor clutch 12 still engaged, the field current i is applied to the terminals of the coil on the stator side. A voltage proportional to dφ / dt is generated when the magnetic field φ generated by is rotated.

At this time, the regenerative current I proportional to the magnetic field φ flows in the stator side coil, and if the regenerative current is made to flow backward to the battery of the vehicle, the kinetic energy of the vehicle is stored as electric power and the vehicle is stored. Can be decelerated. Therefore, if the regenerative braking described above is effectively used when the hybrid vehicle decelerates, the energy consumed by the friction braking or the like can be recovered, and the fuel efficiency can be remarkably improved.

By the way, the regenerative current I naturally has a value corresponding to the magnitude of the electromotive force generated on the stator side, that is, a value corresponding to the magnitude of the magnetic field φ generated on the rotor side coil. Further, the torque required to rotate the rotor from the outside to generate the regenerative current also has a value corresponding to the magnetic field φ. Therefore, in the electric motor 12 of the present embodiment, the magnitude of the regenerative current I generated by appropriately varying the field current i flowing through the rotor side coil, and the braking force exerted by the electric motor 12 when the regenerative current is generated. It is possible to appropriately control the size of.

Therefore, when the vehicle is traveling at a high speed of 80 km / h or more, the regenerative braking is mainly used to secure the braking force. Therefore, in step 122, the field current flowing through the rotor side coil is set to a predetermined "large". It is set to the standard. Therefore, when the accelerator pedal is fully closed while the vehicle is traveling at a vehicle speed of 80 km / h or more using the electric motor 12 as a power source, the electric motor 12 acts as a generator and regenerates at a “large” level set. The current will be regenerated to the battery.

After setting the magnitude of the braking force exerted by the electric motor 12 in this way, in step 124, the value of the brake flag Fb is checked. Then, when Fb is not "1", that is, when the positive braking force is not requested, the braking force is secured only by the regenerative braking, and the current process is ended.

On the other hand, in step 124, Fb =
If it is determined to be "1", the braking force is positively requested, and therefore the process of forcibly operating the internal combustion engine 11 is performed. That is, the process proceeds to step 126 and the IG
The switch 11f is turned on so that the internal combustion engine 11 can operate, and fuel is supplied to the extent that is supplied when the internal combustion engine 11 is in the idling state, so that the injector 11d and the igniter 1 can properly burn the fuel.
1e is put in the standby state.

Then, in step 128, the clutch is gradually turned on in order to engage the engine clutch 13 with a minimum impact, and the internal combustion engine 11 is forcibly put into the operating state, and this processing is ended. Here, the reason why the fuel is supplied to the internal combustion engine 11 in an idling state and the braking force is exerted by so-called firing is to recover as much braking energy as a regenerative current.

When it is determined that the vehicle speed is 50 km / h or more and less than 80 km / h as a result of executing steps 108 and 110, steps 130 to 139 shown in FIG. 5 are executed.

In step 130, the transmission 15 is set to the fourth speed in order to cope with the high speed as in step 120 described above. Then, in step 132, the field current i of the electric motor 12 is set to a predetermined level "medium". This processing is because the vehicle speed is lower than in the case where step 122 is executed, and it is necessary to suppress the braking force due to regenerative braking so that the impact does not become an uncomfortable level.

When the setting of the appropriate field current i is completed, the routine proceeds to step 134, where the value of the brake flag Fb is checked as in the case of the above step 124. And F
If b is not "1", the process is terminated according to the driver's intention. If Fb = "1", the IG switch 11f is turned off in step 136, and then the process proceeds to step 138 to proceed to the engine clutch 13 The process of gradually joining is performed.

In this case, since the regenerative braking by the electric motor 12 does not exert a large braking force and the efficiency of generating the regenerative current I is not high, the IG switch 13 is turned off and the braking force is applied to the internal combustion engine 11 by so-called motoring. Is exerting. Therefore, when the processing from step 136 onward is executed, fuel consumption is not consumed during braking, fuel efficiency can be improved, and in a region where the vehicle speed is less than 80 km / h, exhaust gas is not emitted at all. Is possible.

Then, in step 139, in synchronization with the joint operation of the engine clutch 13, the field current i control for alleviating the impact at the time of joint is executed. That is, after operating the engine clutch 13 in step 138, the field current i that is passed through the rotor side coil of the electric motor 12 is changed according to the field current i-time t map shown in the frame of step 139 in FIG. This processing ends.

Thereafter, this routine is started, and every time these steps 138 and 139 are executed, the engine clutch 13 is gradually engaged and the field current i is appropriately controlled. As a result, the impact generated by the engagement of the engine clutch 13 is absorbed by the change in the braking force exerted by the electric motor 12, and the braking force transmitted to the transmission 15 smoothly increases. The engine brake can be effectively applied without any change.

When it is determined in steps 108 to 112 that the vehicle speed is 20 km / h or more and less than 50 km / h, the processes of steps 140 to 149 shown in FIG. 5 are executed.

In order to obtain an appropriate braking force by engine braking when the vehicle speed is at this level, the transmission 15
Must be set to the third speed, and in step 140, the processing is first performed. Next, at step 142, the field current i to be passed through the electric motor 12 is set. Incidentally, this time, the field current i is set to a predetermined level "small" in consideration of the low vehicle speed.

Then, in step 144, it is determined whether or not the brake flag Fb is "1", and the driver is not actively braking, that is, Fb.
If ≠ “1”, the strong braking force should not be exerted, and therefore the current processing is ended.

On the other hand, when it is determined that Fb = "1", the IG switch 11f is turned off in step 146, and then in steps 148 and 149, as in steps 134 to 139. The engagement of the engine clutch 13 and the field current i control are executed.

In this processing, the vehicle speed is 20 km / h or more 5
Since it is executed when the speed is less than 0 km / h, compared to the case where the above step 138 is executed, the engine clutch 13
Small impact due to splicing. Therefore, the field current i control executed in step 149 in order to absorb the shock may be controlled to be narrower than the control executed in step 139.

In FIG. 5, the field current i-time map shown in the frame of step 149 is set such that its fluctuation width is set smaller than that of the map shown in the frame of step 139 in consideration of the actual situation. Is.

If it is determined in steps 108 to 114 that the vehicle speed is 10 km / h or more and less than 20 km / h, steps 150 to 156 shown in FIG. 5 are executed.

When the vehicle speed is at this level, it is necessary to set the transmission 15 to the second speed in order to obtain an appropriate braking force by the engine brake. In step 150, that processing is first performed. When this process is completed, the field current i
In step 152, the brake flag Fb is discriminated without performing the setting.

In other words, this process is a process executed in a low speed region where the vehicle speed is less than 20 km / h, regardless of whether or not the driver actively requests the braking force. It is necessary to suppress unintended braking force as small as possible. For this reason, when the vehicle speed is in a region where the motor 1 is used,
It is configured such that the field current i is stopped from flowing in 2 and regenerative braking is not executed.

Then, in step 152, Fb ≠
If it is determined to be "1", it means that the braking force should not be exerted, so that the processing of this time is ended and Fb =
If it is determined to be "1", the IG switch 11f is turned off in step 154, and then step 15
In 6, the joint control of the engine clutch 13 is executed, and the current processing is ended.

As described above, in the hybrid vehicle equipped with the device of this embodiment, the internal combustion engine 11 is forcibly operated appropriately during braking even when the vehicle is traveling with the electric motor 12 as the power source. Therefore, it is possible to prevent the internal combustion engine 11 mounted on the hybrid vehicle from being stopped for a long period of time, and avoid problems such as deterioration of restartability of the internal combustion engine.

Further, according to the apparatus of this embodiment, when the vehicle is in a predetermined traveling state, the braking force by the engine braking by the internal combustion engine 11 and the regenerative braking by the electric motor 12 is surely exerted, so that the load on the braking mechanism is increased. Is reduced. Therefore, it also has an effect of suppressing wear of the wear material such as the brake pad.

In the above embodiment, only the control of the field current i is adopted as the means for controlling the braking force exerted by the regenerative braking of the electric motor 12, but the invention is not limited to this and, for example, regenerative braking is possible. The configuration may be such that control is performed by focusing on the voltage of the battery that regenerates the current I and the remaining battery level.

That is, the braking force exerted by the electric motor 12 is a value determined by the magnetic field φ determined by the field current i and the regenerative current I generated. Further, the regenerative current I is a value determined by the differential pressure between the electromotive force generated in the electric motor 12 during regeneration and the battery voltage, the storage capacity of the battery, and the like. Therefore, if the field current i supplied to the electric motor 12 is controlled according to the battery voltage or the battery remaining amount, the braking force by regenerative braking can be controlled with higher accuracy than in the case of the above embodiment. Is possible.

In this case, as means for detecting the remaining amount of the battery, for example, a method of monitoring the specific gravity of the electrolytic solution of the battery, a method of accumulating the current flowing out of the battery, a method of accumulating the flowing-in current are known. It can be realized by a method. Then, in a situation where the battery is sufficiently charged and the regenerative current I cannot be absorbed, if the regenerative current I is consumed by an appropriate resistor, a stable braking force can always be secured by the electric motor 12. It will be possible.

Further, in the above embodiment, the electric motor 12
The execution conditions for regenerative braking, motoring and firing of the internal combustion engine 11, etc. are set by the vehicle speed and whether or not the brake pedal is operated. However, the present invention is not limited to this. May be used as a parameter.

When such a configuration is adopted, the braking request by the driver can be detected with higher accuracy as compared with the above-described embodiment, and the braking force control can be executed in accordance with the actual situation. It will be possible.

Further, it is not essential to directly connect the output shaft of the internal combustion engine and the axle of the drive wheels, but it may be connected indirectly via an electric motor. In this case, by controlling the electric motor clutch, the connection between the output shaft of the internal combustion engine and the axles of the drive wheels is controlled.

Further, although the present embodiment employs a configuration in which the gear position of the transmission is controlled according to the vehicle speed, it can be omitted.

[0078]

As described above, according to the present invention, the internal combustion engine can be forcibly operated while the hybrid vehicle is running as the electric power source of the electric motor. Further, since the compulsory operation is executed by utilizing the braking force of the vehicle, the running energy of the hybrid vehicle does not suffer a loss, and the wear of the brake mechanism installed on each wheel is reduced. It

As described above, according to the braking control apparatus for a hybrid vehicle of the present invention, it is possible to prevent the internal combustion engine from stopping for a long period of time without deteriorating the fuel consumption of the vehicle. Therefore, unlike the conventional hybrid vehicle, even if the electric motor is used for a long time, the startability of the internal combustion engine does not deteriorate.

[Brief description of drawings]

FIG. 1 is a principle diagram of a braking control device for a hybrid vehicle according to the present invention.

FIG. 2 is a conceptual diagram of the configuration of an embodiment of a braking control device for a hybrid vehicle according to the present invention.

FIG. 3 is a block configuration diagram showing a hardware configuration of a control computer of the apparatus of this embodiment.

FIG. 4 is a flowchart (part 1) of an example of a routine process executed by a control computer of the apparatus according to the present embodiment.

FIG. 5 is a flowchart (part 2) of an example of a routine process executed by the control computer of the apparatus of this embodiment.

[Explanation of symbols]

 1, 11 Internal combustion engine 2, 12 Electric motor 3 Axle 4 Connection means 5 Accelerator operation amount detection means 6 Vehicle running state detection means 13 Engine clutch 14 Electric motor clutch 15 Transmission 16 Brake switch 17 Idle switch 18 Vehicle speed sensor 20 Control computer

Claims (1)

[Claims] 1. An internal combustion engine and an electric motor are provided as power sources, and a connecting means for controlling the connection between an output shaft of the internal combustion engine and an axle of driving wheels is provided. A braking control device for a hybrid vehicle that controls a braking characteristic of the hybrid vehicle generated by the electric motor, the accelerator operation amount detecting means detecting an operation amount of an accelerator operation member used for operating a driving force generated by the power source. A vehicle traveling state detecting means for detecting a traveling state of the vehicle; and a detection value of the accelerator operation amount detecting means not more than a predetermined value, and the vehicle traveling state detecting means detects a predetermined traveling state. A braking control device for a hybrid vehicle, comprising: a connection control means for connecting the connection means.