JP2009166621A - Driving force controller of four-wheel drive car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly control the temperature of an exhaust emission control catalyst by utilizing a generator for supplying power to a motor in a driving force controller of a four-wheel drive car in which the driven wheels of a vehicle are driven by the motor. <P>SOLUTION: In the four-wheel drive car, main drive wheels are driven by an internal combustion engine, and the driven wheels are driven by the motor. The second generator driven by the internal combustion engine when the driven wheels are driven to supply a power to the motor comprises a cooling fan which is disposed near the catalyst for purifying the exhaust gas of the internal combustion engine and which cools the second generator by introducing the outside air and blows air to the catalyst. The driving forces of the driven wheels are increased when the temperature T of the catalyst is lower than an activation temperature Ta (S120). When the temperature T of the catalyst is equal to or higher than a degradation temperature Tb, the driving forces of the driven wheels are lowered (S140). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a driving force control device for a four-wheel drive vehicle in which driven wheels of a vehicle are driven by an electric motor.

  Conventionally, a four-wheel drive vehicle in which a main drive wheel (front wheel of a vehicle) is driven by the power of an internal combustion engine and a slave drive wheel (rear wheel of the vehicle) is driven by an electric motor has been put into practical use (for example, Patent Documents). 1). Such a four-wheel drive vehicle is equipped with a generator that supplies electric power to an electric motor that drives the driven wheels, in addition to an auxiliary machine provided in the internal combustion engine and a generator that supplies electric power to the rechargeable battery. Thus, in the generator mounted to drive the driven wheels, power is generated only during the driving period of the driven wheels.

Further, since the generator supplies electric power necessary for driving the driven wheels to the electric motor, relatively large heat is generated during power generation. For this reason, the structure which cools a generator is employ | adopted, and in the generator of patent document 1, in order to avoid that a foreign material permeates from the ventilation window which a cooling fan takes in outside air, it uses the cooling water of an engine. A water-cooled cooling device is used.
JP 2001-253256 A

  By the way, the exhaust system of the internal combustion engine is provided with an exhaust purification catalyst for purifying the exhaust of the engine. Since this catalyst is not activated at a low temperature and has a low exhaust purification capability, it is necessary to raise the temperature of the catalyst and activate it at an early stage, particularly when the engine is started. Further, when the temperature of the catalyst rises excessively, it is desirable to lower it to an appropriate temperature in order to suppress deterioration.

  Here, in the generator of the four-wheel drive vehicle described in Patent Document 1, the heat generated in the generator is not effectively used to activate the exhaust purification catalyst, and the catalyst is lowered to an appropriate temperature. It is not considered to use a generator.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a generator for supplying electric power to a motor in a driving force control device for a four-wheel drive vehicle in which driven wheels of the vehicle are driven by the motor. Is to appropriately control the temperature of the exhaust purification catalyst.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, an internal combustion engine that drives a main drive wheel of a vehicle, an electric motor that drives the driven wheel, and an electric power that is operated by the engine when the driven wheel is driven to supply electric power to the motor. A driving force control device for a four-wheel drive vehicle, comprising: a generator that performs the operation and a catalyst that purifies exhaust of the engine, wherein the catalyst is disposed in the vicinity of the generator, and the temperature of the catalyst is higher than the activation temperature. The gist of the invention is to have a driven wheel control means for increasing the driving force of the driven wheel when the driving force is low.

  According to the above configuration, the catalyst is disposed in the vicinity of the generator, and when the driven wheel is driven, the driving force of the driven wheel is increased when the temperature of the catalyst is lower than the activation temperature. Heat generated from the generator operated by the internal combustion engine increases. And since the heat | fever generated in this way is given with respect to the catalyst arrange | positioned in the vicinity of the generator, the temperature of a catalyst can be raised early. In addition, since this power generator operates by generating power from the internal combustion engine and generates power, operating the power generator increases the load on the internal combustion engine, resulting in an increase in exhaust gas temperature. In other words, the temperature of the exhaust gas passing through the catalyst rises, so that the temperature of the catalyst can be raised. Therefore, when the temperature of the catalyst is lower than the activation temperature, the catalyst can be activated early using a generator mounted to drive the driven wheels. It should be noted that the generator mounted to drive the driven wheels in this way is capable of intermittent operation such as operating and generating electricity as needed, unlike a generator that requires constant power generation. Therefore, it can operate according to the catalyst temperature.

  According to a second aspect of the present invention, an internal combustion engine that drives a main drive wheel of a vehicle, an electric motor that drives the driven wheel, and an electric power that is operated by the engine when the driven wheel is driven to supply electric power to the motor. A driving force control device for a four-wheel drive vehicle, comprising: a generator that performs the operation and a catalyst that purifies the exhaust of the engine. The catalyst is disposed in the vicinity of the generator, and the temperature of the catalyst is equal to or higher than the deterioration temperature. The gist of the invention is that it sometimes includes slave drive wheel control means for reducing the drive force of the slave drive wheel.

By the way, when the temperature of a catalyst rises too much, there exists a possibility that the exhaust gas purification capability may fall because the catalyst deteriorates.
According to the above configuration, when the temperature of the catalyst is equal to or higher than the deterioration temperature, the driving force of the driven wheel is reduced. An excessive temperature rise of the catalyst can be suppressed.

  According to a third aspect of the present invention, in the driving force control apparatus for a four-wheel drive vehicle according to the second aspect, the slave drive wheel control means is configured to provide the slave drive wheel when the temperature of the catalyst is equal to or higher than a deterioration temperature. The gist is to prohibit the driving of

  According to the above configuration, since the driving of the driven wheel is prohibited when the temperature of the catalyst is equal to or higher than the deterioration temperature, the heat generation of the generator can be stopped by stopping the operation of the generator. An excessive temperature rise can be effectively suppressed.

  According to a fourth aspect of the present invention, in the driving force control device for a four-wheel drive vehicle according to any one of the first to third aspects, the generator is air-cooled by being cooled by introducing outside air with a cooling fan. The gist of the invention is that the cooling fan is provided so as to be able to blow air to the catalyst.

  According to the above configuration, the generator is an air-cooled generator that cools by introducing outside air with the cooling fan, and the cooling fan is provided so as to blow air to the catalyst. Thereby, the heat generated during operation of the generator can be supplied to the catalyst by the action of the cooling fan. Therefore, the heat generated by the generator can be used more effectively for raising the temperature of the catalyst.

  On the other hand, since the heat generation of the generator stops when the generator is stopped, the catalyst can be cooled by blowing air from a cooling fan. Therefore, by applying this configuration to the configuration according to claim 2 or 3, an excessive temperature increase of the catalyst can be more effectively suppressed.

  According to a fifth aspect of the present invention, in the driving force control device for a four-wheel drive vehicle according to any one of the first to fourth aspects, the two-wheel drive mode for driving only the main drive wheel, the main drive wheel, and the slave drive wheel. The gist of the present invention is to further include mode determination means for the occupant to select a four-wheel drive mode for driving the drive wheels, and to control the slave drive wheel control means in preference to the determination by the mode determination means.

  According to the above configuration, the occupant further includes mode determination means for determining a two-wheel drive mode for driving only the main drive wheel and a four-wheel drive mode for driving the main drive wheel and the slave drive wheel, and the mode determination means. The determination by is prioritized and the control by the driven wheel control means is suppressed. For this reason, when the two-wheel drive mode is selected to suppress fuel consumption, or when the four-wheel drive mode is selected when traveling on a rough road, these selections can be prioritized. When the two-wheel drive mode and the four-wheel drive mode are not particularly determined, the control by the driven wheel control unit is executed as described above.

(First embodiment)
Hereinafter, a first embodiment in which a driving force control device for a four-wheel drive vehicle according to the present invention is embodied will be described with reference to FIGS. In the following description, the front-rear direction coincides with the front-rear direction of the vehicle, and the left-right direction coincides with the left-right direction when the vehicle moves forward.

  As schematically shown in FIG. 1, a front portion of the four-wheel drive vehicle 1 is provided with a pair of left and right main drive wheels (front wheels) 2 driven by rotation transmitted from the internal combustion engine 5. In the portion, a pair of left and right driven wheels (rear wheels) 3 driven by the electric motor 40 is provided. A front wheel axle 4 and a rear wheel axle 30 that transmit rotational force are connected to the main driving wheel 2 and the slave driving wheel 3, respectively. The front wheel axle 4 is provided with a transmission 6 for changing the speed of rotation transmitted from the internal combustion engine 5. As a result, the power (rotational torque) of the internal combustion engine 5 is transmitted to the main drive wheel 2 via the transmission 6 and the front wheel axle 4.

  The rear wheel axle 30 includes a speed reducer 31 that reduces the speed of rotation transmitted from the electric motor 40, and a differential gear 33 that distributes rotation transmitted to the axle 30 via the speed reducer 31 to the left and right driven wheels 3. And are provided. Then, the driving force of the electric motor 40 is transmitted to the differential gear 33 via the speed reducer 31, whereby the driving force of the electric motor 40 is transmitted to the driven wheels 3.

  The exhaust system of the internal combustion engine 5 is provided with an exhaust purification catalyst 7 for purifying exhaust exhausted from the engine 5, and a catalyst temperature sensor 7 a for detecting the catalyst temperature T is attached to the catalyst 7. . The lowest temperature among the catalyst temperatures T at which the exhaust purification ability of the catalyst 7 is sufficiently exhibited corresponds to the activation temperature Ta, and the catalyst 7 may be deteriorated due to excessive increase in the catalyst temperature T. The lowest temperature corresponds to the deterioration temperature Tb. The activation temperature Ta and the deterioration temperature Tb are determined in advance based on experiments and the like.

  The internal combustion engine 5 includes a first generator 10 that supplies power to the auxiliary machines of the engine 5, the battery 11, and the like as a generator that is operated by the power of the engine 5, and a second that supplies power to the motor 40. A generator 20 is provided. The battery 11 is a 12 V lead-acid battery that is charged by the power supplied from the first generator 10, and supplies power to the auxiliary machines of the internal combustion engine 5. The electric motor 40 is a well-known separately-excited DC motor capable of field control. A dotted line shown in FIG. 1 indicates a power supply path.

  The four-wheel drive vehicle 1 is provided with an electronic control unit (ECU) 50 that comprehensively controls various devices mounted on the vehicle 1. In addition to the arithmetic unit (CPU), the ECU 50 is provided with a memory that stores and holds various control programs, arithmetic maps, data calculated when the control is executed, and the like. Then, the ECU 50 detects the traveling state of the vehicle 1 based on signals output from various sensors provided in the four-wheel drive vehicle 1, and executes each control for the internal combustion engine 5, the transmission 6, and the like.

  Further, the four-wheel drive vehicle 1 includes a drive mode selection switch 51 that allows the occupant to select a two-wheel drive mode for driving only the main drive wheel 2 and a four-wheel drive mode for driving the main drive wheel 2 and the slave drive wheel 3. Is provided. The drive mode selection switch 51 corresponds to mode determination means, and a signal corresponding to the determined mode is output to the ECU 50. Then, the ECU 50 calculates the driving force required for the driven wheels 3 based on signals output from the drive mode selection switch 51, signals output from various sensors provided in the four-wheel drive vehicle 1, and the like. To do. And ECU50 performs each control about the 2nd generator 20, the electric motor 40, etc. based on this calculated driving force.

  As shown in detail in FIG. 2, the first generator 10, the second generator 20, and the catalyst 7 are disposed in front of the internal combustion engine 5. A crank pulley 9 is attached to the tip of a crankshaft 8 that extends in the left-right direction inside the internal combustion engine 5 and outputs the power of the engine 5 as a rotational force. The crank pulley 9 is connected to a pulley 19 attached to the rotating shaft of the first generator 10 and a pulley 29 attached to the rotating shaft 23 of the second generator 20 via a belt B. Then, based on the rotation of the crank pulley 9 transmitted to the pulleys 19 and 29 via the belt B, electric power is generated in the first generator 10 and the second generator 20. The first generator 10 always generates power and supplies power to the battery 11 and the like, and the second generator 20 generates power and supplies power to the motor 40 only when driving the driven wheels 3. .

  As shown in FIG. 3, the second generator 20 includes a rotating shaft 23 that rotates together with the pulley 29, a rotor 21 that is connected to the rotating shaft 23 and rotates together with the rotating shaft 23, and a gap between the second generator 20 and the rotor 21. And a stator 22 that is fixed to the outer housing 28. The rotating shaft 23 is disposed along the left-right direction at the approximate center of the second generator 20 so as to be substantially parallel to the crankshaft 8. The second generator 20 includes an electric circuit, and power is supplied from the battery 11 and the first generator 10 via the electric circuit. Note that a part of the output power of the second generator 20 is also supplied to the second generator 20 via an electric circuit. When the field current is supplied to the field coil of the rotor 21 in this way, electric power is generated in the stator 22, and this electric power is rectified by the rectifier circuit and converted into DC electric power and then supplied to the electric motor 40. Is done. The second generator 20 can output higher power than the first generator 10, and this output power is variable depending on the number of rotations of the rotating shaft 23 and the field current flowing in the field coil. Be controlled.

  The right side surface 28R of the housing 28 is formed with an outside air inlet 25 through which outside air is taken into the second generator 20, and the left side surface 28L opposite to the right side surface 28R is provided with the inside of the second generator 20. A blower port 26 through which gas is discharged to the catalyst 7 side is formed. A cooling fan 24 that always rotates around the rotation shaft 23 is provided at the left end of the rotation shaft 23. The cooling fan 24 takes in outside air through the outside air inlet 25 and blows air to the catalyst 7 through the air outlet 26. Thereby, during power generation, the second generator 20 is cooled by transferring heat to the outside air from the rotor 21 and the stator 22 that have generated heat, and the outside air whose temperature has been raised is blown to the catalyst 7. As a result, the catalyst 7 is warmed up. On the other hand, when the power generation is stopped, the outside air introduced into the second generator 20 is blown as it is to the catalyst 7 without increasing the temperature, thereby cooling the catalyst 7.

  Further, the ECU 50 controls the field current flowing in the field coil of the second generator 20 to control the output voltage, and also controls the field current flowing in the field coil of the electric motor 40 to drive its driving force. Control. The ECU 50 corresponds to the driven wheel control means.

  Next, slave drive wheel control by the ECU 50 will be described with reference to FIG. A series of processes shown in the flowchart of FIG. 3 is executed by the ECU 50 with a predetermined period immediately after the internal combustion engine 5 is started.

  In this series of processes, it is first determined whether or not the four-wheel drive mode is permitted (step S100). Specifically, it is determined whether or not the four-wheel drive mode is selected based on a signal from the drive mode selection switch 51.

  When it is determined that the four-wheel drive mode is not permitted, that is, that the two-wheel drive mode is selected (step S100: NO), driving of the driven wheels 3 is prohibited by the occupant. Therefore, priority is given to the prohibition determination by the passenger, and the series of processes is terminated.

On the other hand, when it is determined that the four-wheel drive mode is permitted (step S100: YES), the following "subordinate drive wheel control" is executed.
Here, when the four-wheel drive mode is permitted as described above, that is, when the drive of the driven wheel 3 is permitted, the signals output from the various sensors provided in the four-wheel drive vehicle 1 are used. Based on this, the running state of the vehicle 1 is detected, and the driving force (first driving force) required for the driven wheels 3 is calculated based on this running state. The second generator 20 and the electric motor 40 are controlled so that the calculated first driving force is obtained. In the “subordinate driving wheel control” described below, the first driving force calculated as described above is adjusted based on the catalyst temperature T, and control for setting the second driving force or the third driving force is performed.

Therefore, it is first determined whether or not the catalyst temperature T is lower than the activation temperature Ta (step S110). Specifically, the determination is made based on the output signal of the catalyst temperature sensor 7a.
When it is determined that the catalyst temperature T is lower than the activation temperature Ta (step S110: YES), it is determined that the exhaust purification capacity of the catalyst 7 is not sufficiently exhibited, and the temperature T of the catalyst 7 is determined. The driving force of the driven wheels is increased so as to increase the speed (step S120).

  Here, the increase in the driving force of the driven wheels in step S120 is performed by setting a second driving force that is a driving force larger than the first driving force. The setting of the second driving force is performed based on the catalyst temperature T by referring to a predetermined map. The driving power of the driven wheels 3 is increased by increasing the operating rate of the second generator 20 and increasing the output power supplied to the electric motor 40 so that the set second driving power can be obtained. . As a result, the generated heat of the second generator 20 is increased, and the generated heat is transmitted to the outside air introduced by the cooling fan 24, whereby the heated outside air is supplied to the catalyst 7.

  On the other hand, when it is determined that the catalyst temperature T is not lower than the activation temperature Ta, that is, that the catalyst temperature T is equal to or higher than the activation temperature Ta (step S110: NO), the exhaust purification capacity of the catalyst 7 is Since it is determined that the catalyst is sufficiently exerted, it is then determined whether or not the catalyst temperature T is equal to or higher than the deterioration temperature Tb (step S130). When it is determined that the catalyst temperature T is equal to or higher than the deterioration temperature Tb (step S130: YES), the catalyst 7 may be deteriorated, so that it is driven to suppress an excessive temperature rise of the catalyst 7. The wheel driving force is reduced (step S140), and the series of processing ends. Specifically, a third driving force that is smaller than the first driving force is set, and the operating rate of the second generator 20 is reduced based on the set third driving force to reduce the electric motor 40. The driving force of the driven wheel 3 is reduced by lowering the output voltage supplied to. The third driving force is set based on the catalyst temperature T by referring to a predetermined map. Thereby, since the heat generation of the second generator 20 is suppressed, the temperature of the outside air that passes through the second generator 20 and is supplied to the catalyst 7 by the cooling fan 24 decreases, and the temperature of the catalyst 7 increases excessively. Is suppressed.

  On the other hand, when it is determined that the catalyst temperature T is not equal to or higher than the deterioration temperature Tb, that is, that the catalyst temperature T is lower than the deterioration temperature Tb (step S130: NO), the temperature T of the catalyst 7 is appropriate. It is judged, the control for driving the driven wheel 3 with the first driving force is continued, and the series of processes is completed.

According to 1st Embodiment described above, there can exist the following effects.
(1) Since the catalyst 7 is disposed in the vicinity of the second generator 20 and the driving force of the driven wheel 3 is increased when the temperature T of the catalyst 7 is lower than the activation temperature Ta (step S120), The heat generated from the second generator 20 increases, and the generated heat is given to the catalyst 7. Thereby, the temperature T of the catalyst 7 can be raised early.

  In addition, since the second generator 20 operates and generates power when the power of the internal combustion engine 5 is transmitted, operating the second generator 20 increases the load on the internal combustion engine 5. As the exhaust temperature rises. That is, the temperature of the exhaust gas passing through the catalyst 7 rises, so that the temperature of the catalyst 7 can be raised.

  Accordingly, when the temperature T of the catalyst 7 is lower than the activation temperature Ta, for example, when the internal combustion engine 5 is cold started, the second generator 20 mounted to drive the driven wheels 3 is used. In other words, the catalyst 7 can be warmed up from the inside by raising the exhaust temperature of the internal combustion engine 5, and warmed up from the outside by the second generator 20, thereby enabling early activation of the catalyst 7.

  (2) Unlike the first generator 10 that requires constant power generation, the second generator 20 that is mounted to drive the driven wheels 3 performs an intermittent operation such that it operates and generates power as necessary. It is possible to operate according to the catalyst temperature T.

  (3) When the catalyst temperature T is equal to or higher than the deterioration temperature Tb, the driving force of the driven wheel 3 is reduced (step S140). And an excessive temperature rise of the catalyst 7 can be suppressed.

  (4) The second power generator 20 is an air-cooled power generator that cools by introducing outside air with the cooling fan 24, and the cooling fan 24 is provided so as to blow air to the catalyst 7. Heat generated during operation of the machine 20 can be supplied to the catalyst 7 by the action of the cooling fan 24. Therefore, the heat generated in the second generator 20 can be used more effectively for raising the temperature of the catalyst 7.

  (5) The second generator 20 is an air-cooled generator that cools by introducing outside air with the cooling fan 24, and the cooling fan 24 is provided so as to blow air to the catalyst 7. When heat generation is suppressed by suppressing the power generation of the machine 20, the catalyst 7 can be cooled by blowing air from the cooling fan 24.

  (6) Since the driven wheel control is executed when the four-wheel drive mode is permitted, when the two-wheel drive mode is selected by the occupant, the selection is prioritized to drive the driven wheel 3. You can avoid doing it.

(Second Embodiment)
Hereinafter, a second embodiment of the driving force control device for a four-wheel drive vehicle according to the present invention will be described with reference to FIG. In addition, detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol to the structure similar to 1st Embodiment. The present embodiment is different from the first embodiment in the following points. That is, in the first embodiment, when the four-wheel drive mode is selected by the drive mode selection switch 51, it is determined that the four-wheel drive is permitted by the occupant, and the driven wheel control, that is, the first The second driving force or the third driving force was set by adjusting one driving force (steps S120 and S140). However, in this embodiment, the drive mode selection switch is configured so that an automatic mode that does not particularly determine the four-wheel drive mode and the two-wheel drive mode can be selected, and the four-wheel drive mode is selected by the drive mode selection switch. In this case, it is assumed that driving of the driven wheels 3 with the first driving force is required by the occupant. That is, when the four-wheel drive mode is determined, only the first driving force is set according to the determination, and the driven wheel control is executed only when it is not particularly determined (when the automatic mode is selected). The second driving force or the third driving force is set.

  A series of processes shown in the flowchart of FIG. 5 is repeatedly executed by the ECU 50 at a predetermined cycle immediately after the internal combustion engine 5 is started. In addition, description of a specific aspect is abbreviate | omitted about the process similar to 1st Embodiment.

  As shown in the figure, in this series of processing, it is first determined whether either the two-wheel drive mode or the four-wheel drive mode is selected (step S200). If it is determined that one of them has been selected (step S200: YES), the determination by the occupant is prioritized and the series of processes ends. Specifically, when the two-wheel drive mode is selected, only the main drive wheel 2 is driven and the drive of the slave drive wheel 3 is prohibited. When the four-wheel drive mode is selected, the driving force (first driving force) required for the slave driving wheel 3 is calculated based on the traveling state of the four-wheel driving vehicle 1, and this first driving is calculated. It is controlled so that force can be obtained.

  On the other hand, when it is determined that neither the two-wheel drive mode or the four-wheel drive mode is selected (step S200: NO), that is, when the automatic mode is selected, the “slave drive wheel control” described below is performed. ”Is executed.

  First, it is determined whether or not the catalyst temperature T is lower than the activation temperature Ta (step S210). When it is determined that the catalyst temperature T is lower than the activation temperature Ta (step S210: YES), it is determined that the exhaust purification capacity of the catalyst 7 is not sufficiently exhibited, and the temperature T of the catalyst 7 is determined. The driving force of the driven wheels is increased so as to increase the speed (step S220). Specifically, this is performed by setting a second driving force that is larger than the first driving force set based on the traveling state of the four-wheel drive vehicle 1. As a result, the heat generation of the second generator 20 increases, so that the outside air that has been heated through the second generator 20 is supplied to the catalyst 7 by the cooling fan 24.

  On the other hand, when it is determined that the catalyst temperature T is not lower than the activation temperature Ta, that is, that the catalyst temperature T is equal to or higher than the activation temperature Ta (step S210: NO), the exhaust purification capacity of the catalyst 7 is Since it is determined that the catalyst is sufficiently exerted, it is then determined whether or not the catalyst temperature T is equal to or higher than the deterioration temperature Tb (step S230). When it is determined that the catalyst temperature T is equal to or higher than the deterioration temperature Tb (step S230: YES), the catalyst 7 may be deteriorated, so that it is driven to suppress an excessive temperature rise of the catalyst 7. The wheel drive is prohibited (step S240), and the series of processes is terminated. Specifically, the driving of the driven wheels 3 is prohibited by stopping the operation of the second generator 20. Thereby, since the heat generation of the second generator 20 is stopped, the temperature of the outside air that passes through the second generator 20 and is supplied to the catalyst 7 by the cooling fan 24 is lowered, and the catalyst 7 is cooled.

  On the other hand, when it is determined that the catalyst temperature T is not equal to or higher than the deterioration temperature Tb, that is, the catalyst temperature T is lower than the deterioration temperature Tb (step S230: NO), the temperature T of the catalyst 7 is appropriate. It is judged, the control for driving the driven wheel 3 with the first driving force is continued, and the series of processes is completed.

According to the second embodiment described above, the following operational effects can be obtained in addition to the operational effects according to the above (1), (2), and (4).
(7) When the catalyst temperature T of the catalyst 7 is equal to or higher than the deterioration temperature Tb, the driving of the driven wheel 3 is prohibited (step S240). Therefore, the operation of the second generator 20 is stopped to stop the operation of the generator 20 Heat generation can be stopped, and an excessive temperature rise of the catalyst 7 can be effectively suppressed. That is, the effect of suppressing the temperature rise of the catalyst 7 is higher than the effect shown in (3) above.

  (8) The cooling fan 24 is provided so as to be able to blow air to the catalyst 7, and the second generator 20 is stopped in order to stop the operation of the second generator 20 and stop the heat generation of the generator 20 (step S240). The temperature of the gas blown by the cooling fan 24 is further reduced as compared with the case of suppressing the operation of (step S140). Therefore, the temperature of the catalyst 7 can be effectively reduced. That is, the effect of lowering the temperature of the catalyst 7 is higher than the effect shown in (5) above.

  (9) The determination of the occupant who selects the two-wheel drive mode for driving only the main drive wheel 2 and the four-wheel drive mode for driving the main drive wheel 2 and the slave drive wheel 3 is given priority, and these are selected. In this case, the driven wheel control is suppressed. For this reason, when the two-wheel drive mode is selected to suppress fuel consumption, or when the four-wheel drive mode is selected when traveling on a rough road, these selections can be prioritized.

  (10) The slave drive wheel control is executed only when the two-wheel drive mode and the four-wheel drive mode are not particularly determined (when the automatic mode is selected). Therefore, since the driving force required for the driven wheel 3 can be set relatively freely, the driving of the driven wheel is prohibited so as to lower the catalyst temperature T when the catalyst temperature T is equal to or higher than the deterioration temperature. (Step S240) is facilitated.

(Other embodiments)
Note that the driving force control apparatus for a four-wheel drive vehicle according to the present invention is not limited to the configuration exemplified in the above embodiment, and is implemented as the following form, for example, appropriately modified from the above embodiment. You can also

-It is not restricted to the structure by which the 1st generator 10, the 2nd generator 20, and the catalyst 7 are arrange | positioned ahead of the internal combustion engine 5, If the catalyst 7 is the structure arrange | positioned in the vicinity of the 2nd generator 20, Good.
In the first embodiment, the outside air inlet 25 through which the outside air is taken into the second generator 20 is formed on the right side surface 28R of the housing 28, and the second generator is formed on the left side surface 28L facing the right side surface 28R. A blower port 26 through which the gas in 20 is discharged to the catalyst 7 side is formed. However, the formation positions of the outside air inlet and the air outlet are not limited to this, and for example, the outside air inlet may be formed on the outer peripheral surface of the generator.

  In each of the above-described embodiments, the example in which the driven wheel control is executed in consideration of the selection of the drive mode based on the signal from the drive mode selection switch 51 (steps S100 and S200) has been described. However, the slave drive wheel control may be executed regardless of the selection of the drive mode.

  For example, as shown in the flowchart of FIG. 6, it is determined whether or not the catalyst temperature T is lower than the activation temperature Ta (step S300), and it is determined that the catalyst temperature T is lower than the activation temperature Ta. (Step S300: YES), the driving force of the driven wheels may be increased (step S310). On the other hand, when it is determined that the catalyst temperature T is not lower than the activation temperature Ta (step S300: NO), it is determined that the exhaust gas purification capability of the catalyst 7 is sufficiently exerted, and thus the series of processes is terminated. To do. Even in this case, it is possible to achieve the effects similar to the above (1), (2) and (4).

  Further, for example, as shown in the flowchart of FIG. 7, it is determined whether or not the catalyst temperature T is equal to or higher than the deterioration temperature Tb (step S400), and when it is determined that the catalyst temperature T is equal to or higher than the deterioration temperature Tb. (Step S400: YES), the driving force of the driven wheels may be reduced regardless of the selection of the drive mode (Step S410). On the other hand, when it is determined that the catalyst temperature T is not equal to or higher than the deterioration temperature Tb (step S400: NO), it is determined that there is no possibility that the catalyst 7 is deteriorated, and thus the series of processes is terminated. Even in this case, the effects similar to the above (2), (3), and (5) can be achieved.

  In each of the above embodiments, the example in which the electric motor 40 is a separately excited DC motor has been described. However, other types of motors may be used as long as they can control the driving force of the driven wheels 3. For example, an electric motor using AC power can be employed.

In each of the above embodiments, an example is shown in which a single electronic control unit (ECU) 50 is provided, but an electronic control unit for controlling the driving force of the driven wheels 3 may be provided separately.
In each of the above embodiments, an example in which the second generator 20 is air-cooled has been shown. However, a water-cooled generator that circulates cooling water in the generator and cools it may be adopted. Even in this case, by increasing the output power of the second generator, the remaining generated heat can be sent to the catalyst side, and in order to increase the output power of the second generator, The load increases and the exhaust temperature rises, and this also makes it possible to warm up the catalyst. Furthermore, a fan capable of blowing air to the catalyst can be provided outside the housing of the second generator. As a result, the heat of the second generator can be easily sent to the catalyst, and the effect of cooling the catalyst can be obtained.

  In each of the above-described embodiments, the example in which the cooling fan 24 provided in the second generator 20 is disposed so as to be able to blow air to the catalyst 7 has been described. However, the aspect which provides the fan which ventilates in the direction different from a catalyst may be shown. Even in this case, by increasing the output power of the second generator, the generated generated heat can be sent to the catalyst side, and the internal combustion engine 5 is used to increase the output power of the second generator. As a result, the exhaust temperature rises and the catalyst can be warmed up.

  In each of the above-described embodiments, the example in which the driven wheel 3 driven by the electric motor 40 is adopted as the rear wheel has been described. However, a driven wheel may be adopted as the front wheel.

1 is a block diagram showing a schematic configuration of a first embodiment that embodies a driving force control device for a four-wheel drive vehicle according to the present invention. The schematic diagram which looked at the internal-combustion engine of the four-wheel drive vehicle concerning a 1st embodiment, and its peripheral structure from the vehicles front. Schematic which shows the internal structure of the 2nd generator in FIG. 2 with a positional relationship with a catalyst. The flowchart which shows the process sequence about the control concerning 1st Embodiment. The flowchart which shows the process sequence about the control concerning 2nd Embodiment. The flowchart which shows the process sequence about the process in the modification of the driving force control apparatus of the four-wheel drive vehicle concerning this invention. The flowchart which shows the process sequence about the process in the other modification of the driving force control apparatus of the four-wheel drive vehicle concerning this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Four-wheel drive vehicle, 2 ... Main drive wheel, 3 ... Sub-drive wheel, 4 ... Front wheel axle, 5 ... Internal combustion engine, 6 ... Transmission, 7 ... Exhaust gas purification catalyst, 7a ... Catalyst temperature sensor, 8 ... Crank Shaft, 9 ... crank pulley, 10 ... first generator, 11 ... battery, 19, 29 ... pulley, 20 ... second generator, 21 ... rotor, 22 ... stator, 23 ... rotating shaft, 24 ... cooling fan, 25 DESCRIPTION OF SYMBOLS ... Outside air intake, 26 ... Air outlet, 28 ... Housing, 30 ... Rear-wheel axle, 31 ... Reduction gear, 33 ... Differential gear, 40 ... Electric motor, 50 ... ECU, 51 ... Drive mode selection switch.

Claims (5)

An internal combustion engine that drives a main drive wheel of a vehicle, an electric motor that drives the driven wheel, a generator that is operated by the engine when the driven wheel is driven and supplies electric power to the motor, and an exhaust of the engine A driving force control device for a four-wheel drive vehicle comprising a catalyst to be purified,
The catalyst is disposed in the vicinity of the generator;
A driving force control device for a four-wheel drive vehicle, comprising: driven wheel control means for increasing the driving force of the driven wheel when the temperature of the catalyst is lower than the activation temperature. An internal combustion engine that drives a main drive wheel of a vehicle, an electric motor that drives the driven wheel, a generator that is operated by the engine when the driven wheel is driven and supplies electric power to the motor, and an exhaust of the engine A driving force control device for a four-wheel drive vehicle comprising a catalyst to be purified,
The catalyst is disposed in the vicinity of the generator;
A driving force control device for a four-wheel drive vehicle, comprising: driven wheel control means for reducing the driving force of the driven wheel when the temperature of the catalyst is equal to or higher than the deterioration temperature. The driving force control apparatus for a four-wheel drive vehicle according to claim 2,
The driving force control device for a four-wheel drive vehicle, wherein the driven wheel control means prohibits driving of the driven wheel when the temperature of the catalyst is equal to or higher than a deterioration temperature. In the drive force control apparatus of the four-wheel drive vehicle as described in any one of Claims 1-3,
The generator is an air-cooled generator that cools by introducing outside air with a cooling fan, and the cooling fan is provided so as to be able to blow air to the catalyst. Force control device. In the driving force control device for a four-wheel drive vehicle according to any one of claims 1 to 4,
The vehicle further includes mode determination means for the occupant to select a two-wheel drive mode for driving only the main drive wheel and a four-wheel drive mode for driving the main drive wheel and the slave drive wheel, with priority given to the determination by the mode determination means. A drive force control device for a four-wheel drive vehicle, wherein control by the slave drive wheel control means is suppressed.

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