JP5669427B2 - vehicle - Google Patents

Description

  The present invention provides a first driving force for driving one of a front wheel or a rear wheel of a vehicle as a first driving wheel and driving the first driving wheel by one or both of an engine and a motor, and the other as a second driving wheel. The present invention relates to a vehicle including a driving force control means for controlling a second driving force for driving the second driving wheel by a motor.

  Conventionally, in this type of vehicle, as shown in Patent Document 1 below, it is predicted whether or not the driving of the second driving wheel is necessary, and it is predicted that the driving of the second driving wheel by the motor is necessary. A configuration for driving the second drive wheel is known. Here, the case where it is predicted that the driving of the second drive wheel is necessary corresponds to the case where it is determined that the vehicle is starting, running on a low μ road, running in a snow mode, running on a slope, or the like (Patent Document 1 below). Paragraph [0052]).

JP 2000-127790 A

  However, in the conventional vehicle, when it is predicted that the driving of the second drive wheel is necessary, the vehicle is already in the low μ road running, the snow mode running, and the slope running. In other words, this is not a prediction, but only when the vehicle is running on a low μ road, running in a snow mode, or running on a slope, this is detected and the second drive wheel is driven.

  Furthermore, since it takes a certain time to detect the road surface state, there is a problem that the second driving wheel is not driven for a certain period of time even though it is necessary to drive the second driving wheel.

  In view of the above circumstances, an object of the present invention is to provide a vehicle capable of realizing in advance appropriate driving force distribution corresponding to a change in road surface on the course of the vehicle.

The vehicle of the first invention is
A first drive wheel that is one of the front wheels or the rear wheels and is driven by one or both of the engine and the first motor, and a second wheel that is a wheel other than the first drive wheels and is driven by the second motor. A vehicle comprising: a driving wheel; and a driving force control means for controlling a first driving force for driving the first driving wheel and a second driving force for driving the second driving wheel,
First acquisition means for acquiring a first friction coefficient that is a road surface friction coefficient at a first position on the path of the vehicle;
Total driving force determining means for determining a target value of the total driving force of the vehicle based on at least the first friction coefficient acquired by the first acquiring means;
In a range that does not become the slip limit corresponding to the first friction coefficient acquired by the first acquisition means, the target value of the total driving force determined by the total driving force determination means is satisfied and the energy consumption is minimized. Driving force distribution determining means for determining a combination of the first driving force and the second driving force as a target value of the first driving force and the second driving force;
The driving force control means includes the first driving force and the second driving force determined by the driving force distribution determining means and the first driving force and the second driving force before the vehicle reaches the first position. It changes to the target value of 2nd driving force, It is characterized by the above-mentioned.

  According to the vehicle of the first invention, the target values of the first driving force and the second driving force are determined so as not to exceed the slip limit corresponding to the first friction coefficient at the first position. Further, a target value of the first driving force and the second driving force is determined from a combination of the first driving force and the second driving force that minimizes energy consumption when the total driving force of the vehicle is the same. . Then, by changing the first driving force and the second driving force to the target values in advance, the first driving force and the second driving force can be obtained even when there is a change in the road surface condition leading to the first position. The slip corresponding to the first position can be suppressed in advance, and the increase in the energy consumption of the vehicle due to the suppression of the slip can be avoided.

  As described above, according to the vehicle of the first invention, it is possible to realize in advance an appropriate driving force distribution corresponding to a change in the road surface on the course of the vehicle.

Further , according to the vehicle of the first invention, the target value of the total driving force of the vehicle is determined from at least the first friction coefficient of the first position, and the target value of the total driving force is satisfied within a range that does not become the slip limit and A combination of the first driving force and the second driving force that minimizes the energy consumption is determined as these target values. As a result, even when there is a change in the road surface condition leading to the first position, the driving force of the vehicle can correspond to the change in the road surface friction coefficient in advance, and an appropriate response corresponding to the road surface change on the course of the vehicle. Driving force distribution can be realized in advance.

The vehicle of the second invention is the vehicle according to the first invention,
Second acquisition means for acquiring a second friction coefficient that is a road surface friction coefficient of a second position that is a current position of the vehicle;
With
The total driving force determining means is configured to calculate the first friction coefficient and the second friction coefficient from the first friction coefficient acquired by the first acquisition means and the second friction coefficient acquired by the second acquisition means. If the deviation between the coefficients exceeds a predetermined threshold value, and wherein the determined Teisu Rukoto the desired value of the total driving force of the vehicle according to the first coefficient of friction.

According to the vehicle of the second invention, the target value of the total driving force of the vehicle is maintained from the first friction coefficient at the first position and the second friction coefficient at the second position as long as these deviations do not exceed a predetermined threshold value. When the predetermined threshold value is exceeded, it is determined according to the first friction coefficient. Therefore, in the case where the change in the target value of the total driving force needs to be changed while the change in the friction coefficient is large and the target value of the total driving force needs to be changed while suppressing the decrease in drivability due to the change in the target value of the total driving force of the vehicle. The driving force can correspond to the change of the road surface friction coefficient, and appropriate driving force distribution corresponding to the road surface change on the course of the vehicle can be realized in advance.

A vehicle according to a third aspect of the invention is the vehicle according to the first or second aspect of the invention,
The first acquisition means includes: map information of a navigation device mounted on the vehicle; travel history information of a vehicle other than the vehicle on the route; and a road surface that is installed on the route and detects a road surface state. The first friction coefficient is obtained from a part or all of the output information of the detection device.

According to the vehicle of the third invention, the map information of the navigation mounted on the vehicle, the travel history information of the vehicle other than the vehicle on the route, and the road surface that is installed on the route and detects the state of the road surface The first friction coefficient at the first position can be accurately recognized and acquired from a part or all of the output information of the detection device. By appropriately changing the first driving force and the second driving force to the target values based on the first friction coefficient in advance, appropriate driving force distribution corresponding to the road surface change on the course of the vehicle is realized in advance. be able to.

1 is an overall configuration diagram of a vehicle according to an embodiment. The flowchart which shows the process by main ECU in this Embodiment. Explanatory drawing which shows the processing content (FF-> 4WD by making a driving force constant) by main ECU. Explanatory drawing which shows the processing content by main ECU (it reduces driving force and it is FF-> 4WD). Explanatory drawing which shows the other processing content (4WD-> 4WD by reducing a driving force) by main ECU. Explanatory drawing which shows the other processing content (RR-> 4WD by making constant driving force) by main ECU. Explanatory drawing which shows the processing content by main ECU in other embodiment.

  As shown in FIG. 1, the vehicle according to the present embodiment is, for example, a four-wheel drive hybrid vehicle, and includes an engine 1 that is an internal combustion engine, a first motor 11 that rotates by electric power supplied from a battery 2, and It has the 2nd motor 12, and main ECU3 (Electric Control Unit, equivalent to the driving force control means of this invention) which manages and controls these engines 1, the 1st motor 11, the 2nd motor 12, etc. intensively. . The main ECU 3 performs processing based on information acquired through the information acquisition unit 4 connected to the information acquisition unit 4.

  Supplementally, the main ECU 3 is a microcomputer (not shown) including a RAM (Random Access Memory), a ROM (Read Only Memory), a CPU (Central Processing Unit), an input / output interface, a timer, etc., and is recorded in the ROM. The processing is performed in accordance with the programmed program and data.

  Further, the hybrid vehicle includes a front wheel 6 (corresponding to the first drive wheel of the present invention) driven by the engine 1 and the first motor 11 and a rear wheel 7 driven by the second motor 12 (second of the present invention). Corresponding to drive wheels).

  The engine 1 and the first motor 11 are connected to a common drive shaft, and drive the front wheels 6 via a gear mechanism, a differential gear, and the like (both not shown). Similarly, the second motor 12 drives the rear wheel 7 via a gear mechanism, a differential gear, and the like (both not shown).

  The hybrid vehicle further includes a first PDU (Power Drive Unit) 21 that performs power control of the first motor 11 and a second PDU (Power Drive Unit) 22 that performs power control of the second motor 12. The first motor 11 and the second motor 12 also function as a generator under the control of the first PDU 21 and the second PDU 22. That is, the first motor 11 can generate power or regenerate by receiving driving force from the engine 1 or the front wheel 6 and charge the battery 2, and the second motor 12 can regenerate by receiving driving force from the rear wheel 7. To charge the battery 2.

  The main ECU 3 includes a target driving force calculation unit 3A (corresponding to the total driving force determining unit of the present invention), a front and rear wheel distribution ratio determining unit 3B (corresponding to the driving force distribution determining unit of the present invention), and a driving force change. And a management unit 3C.

  The target driving force calculation unit 3 </ b> A is based on the information (road surface information) acquired via the information acquisition unit 4 connected to the information acquisition unit 4 and the target driving force of the entire vehicle (first driving of the front wheels 6, 6). The upper limit threshold value of the force and the second driving force of the rear wheels 7 and 7) is set, and the vehicle is based on the output values of an accelerator opening sensor and a vehicle speed sensor (not shown) within the set upper limit threshold range. The target driving force (instantaneous value) is sequentially calculated.

  The front and rear wheel distribution ratio determining unit 3B determines the target driving force calculated by the target driving force calculating unit 3A based on information (road surface information) acquired via the information acquiring unit 4 connected to the information acquiring unit 4. The distribution ratio to be distributed to the first driving force of the front wheels 6 and 6 and the second driving force of the rear wheels 7 and 7 is determined.

  The driving force change management unit 3C is based on the information (road surface information) acquired via the information acquisition unit 4 connected to the information acquisition unit 4, and the front wheels 6, 6 determined by the front and rear wheel distribution ratio determination unit 3B. The timing for changing the first driving force and the second driving force of the rear wheels 7 and 7 is determined.

  Details of processing by the main ECU 3 will be described later.

  The main ECU 3 is connected to the engine ECU 30, the first motor ECU 31, the second motor ECU 32, and the battery ECU 33. The engine ECU 30 controls the engine 1, and the battery ECU 33 controls the charging / discharging of the battery 2. Is executed. Further, the first motor ECU 31 controls the first motor 11 via the first PDU 21, and the second motor ECU 32 controls the second motor 12 via the second PDU 22.

  The information acquisition unit 4 includes a first information acquisition unit 4A (corresponding to a first acquisition unit of the present invention) and a second information acquisition unit 4B (corresponding to a second acquisition unit of the present invention).

  4A of 1st information acquisition parts acquire the 1st information about the 1st position on the course of vehicles. Here, the first information is the first friction coefficient μ1, which is the road surface friction coefficient at the first position, or information from which this can be derived.

  The first information corresponds to a measurement value obtained by measuring the road surface state at the first position by the outside device. As an out-of-vehicle device, a road surface friction coefficient calculation unit provided in another vehicle on the course of the host vehicle, an information server in which information (first friction coefficient μ1) provided from another vehicle is stored, information transmission such as a beacon Applicable means.

  Further, as the first information, the output value (first friction coefficient μ1) of the road surface friction coefficient calculation unit of the other vehicle, information that can be acquired from the information server, and road surface information (first friction coefficient) provided by the other vehicle μ1), information on the road surface state on the route that can be acquired from information transmitting means such as a beacon (for example, information on a frozen road surface, a wet state, a dry state, etc.).

  Next, the 2nd information acquisition part 4B acquires the 2nd information regarding the 2nd position which is the present driving | running | working road surface. Here, the second information is the second friction coefficient μ2, which is the road surface friction coefficient at the second position, or information from which this can be derived.

  In this embodiment, as the second information, the output values (second friction coefficient μ2) of various road surface friction coefficient calculation units that estimate the second friction coefficient μ2 included in the host vehicle are acquired.

  The configuration of the road surface friction coefficient calculation unit is described in the prior art document (Japanese Patent Laid-Open No. 2009-274582, paragraph [0019]) by the applicant of the present application, and a detailed description thereof is omitted here. The outline of the processing of the road surface friction coefficient calculating section is as follows. The speed V and the brake torque T of the front wheels 6, 6 and the rear wheels 7, 7 are detected by a wheel speed sensor and a brake torque sensor (not shown), respectively, and the relationship of the following equation (1) The second friction coefficient μ2 is calculated from the equation.

μ1 = [T + (I × (dw / dt)) / R] / W
Here, I is a wheel inertia moment, R is a wheel radius, w is a wheel rotational speed, W is a wheel ground load, and a relationship of V = R · w is established.

   Next, details of the processing by the main ECU 3 will be described with reference to the flowchart shown in FIG.

  First, the main ECU 3 acquires the second friction coefficient μ2 that is the friction coefficient of the second position where the host vehicle is currently traveling through the second information acquisition unit 4B of the information acquisition unit 4 (FIG. 2 / STEP 11). .

  Next, the main ECU 3 determines whether or not the first information as the road surface information of the first position, which is the road surface on the course of the host vehicle, can be acquired via the first information acquisition unit 4A of the information acquisition unit 4. (FIG. 2 / STEP 12).

  Then, the main ECU 3 repeats this determination until the first information can be acquired (NO in FIG. 2 / STEP 12), and from the acquired first information at the timing when the first information can be acquired (YES in FIG. 2 / STEP 12). A first friction coefficient μ1, which is a friction coefficient at the first position, is derived.

  Here, the derivation of the first friction coefficient μ1 uses the included first friction coefficient μ1 as it is when the first information itself includes the first friction coefficient μ1. For example, when the first information includes the first friction coefficient μ1 provided by another vehicle, the first friction coefficient μ1 is used as it is.

  On the other hand, when the first friction coefficient μ1 is not included, the first friction coefficient μ1 is estimated from the first information. For example, when the first information is road surface state information (for example, the road surface is frozen, wet, dry, etc.) on the route that can be acquired from information transmitting means such as a beacon, the road surface The corresponding first friction coefficient μ1 is estimated from the state information by referring to a map, table, relational expression or the like (hereinafter referred to as a map or the like) stored in advance in a memory or the like.

  In addition, although the information acquired as 1st information may be acquired about all the road surfaces on the course of the own vehicle, the range acquired based on map information, such as a navigation apparatus which is not shown in figure, according to the distance with the own vehicle. It is preferable to be limited (for example, a range of 5 km ahead of the host vehicle). This avoids changing the first driving force of the front wheels 6 and 6 and the second driving force of the rear wheels 7 and 7 based on the first friction coefficient μ1 at the first position on the path away from the present. can do.

  Next, the main ECU 3 calculates a deviation Δμ between the second friction coefficient μ2 acquired in STEP 11 and the first friction coefficient μ1 derived in STEP 13 (FIG. 2 / STEP 14).

  Next, the main ECU 3 determines the first driving force and the rear wheels of the front wheels 6 and 6 based on whether or not the magnitude | Δμ | of the deviation Δμ calculated in STEP 14 is equal to or greater than a predetermined threshold value. It is determined whether or not the second driving force 7 or 7 needs to be changed (FIG. 2 / STEP 15).

  For example, when the second friction coefficient μ2 at point B in the second position is a dry asphalt road surface and the first friction coefficient μ1 at point A in the first position is a snowy road, the road friction coefficient is high μ. When changing from a road to a low μ road (when μ1 << μ2), the main ECU 3 determines that | Δμ | = | μ1-μ2 | It is determined that the driving force with the second driving force of the rear wheels 7 and 7 (usually 0 on a dry asphalt road surface) needs to be changed.

  If the main ECU 3 determines that there is no need to change the driving force (NO in FIG. 2 / STEP 15), the main ECU 3 ends the series of processes. On the other hand, when the main ECU 3 determines that the driving force needs to be changed (YES in FIG. 2 / STEP 15), the target driving force calculation unit 3A determines the target from the second friction coefficient μ2 and the first friction coefficient μ1. The upper threshold value of the driving force is set (FIG. 2 / STEP 16).

  Specifically, the upper limit threshold value of the target driving force is determined from (1) the magnitude relationship between the second friction coefficient μ2 and the first friction coefficient μ1 and (2) the first friction coefficient μ1. That is, (1) When the magnitude | Δμ | of the deviation between the second friction coefficient μ2 and the first friction coefficient μ1 exceeds a predetermined threshold value, it is determined that the upper limit threshold value of the target driving force needs to be changed. (2) The upper limit threshold of the target driving force corresponding to the first friction coefficient μ1 is determined by referring to a map or the like that defines the first friction coefficient μ1 and the upper limit threshold of the target driving force.

  Here, the upper limit threshold of the target driving force is determined only by the first friction coefficient μ1 based on the second friction coefficient μ2 as well as the first friction coefficient μ1. In this case, the upper limit threshold frequently fluctuates according to the acquired value of the first friction coefficient μ1, but the upper limit threshold of the current target driving force is maintained as much as possible by considering the second friction coefficient μ2. And a decrease in drivability associated with a change in the upper limit threshold of the target driving force can be suppressed.

  For simplicity, the upper limit threshold of the target driving force may be determined by a map or the like that defines the relationship between the first friction coefficient μ1 and the upper limit threshold.

  Next, the front and rear wheel distribution ratio determining unit 3B of the main ECU 3 determines the drive force distribution ratio between the first driving force of the front wheels 6 and 6 and the second driving force of the rear wheels 7 and 7 corresponding to the first friction coefficient μ1. Determine (FIG. 2 / STEP 17, STEP 18).

  First, the front / rear wheel distribution ratio determining unit 3B is a map showing the relationship between the upper limit threshold value of the target driving force and the driving force distribution ratio of the first driving force of the front wheels 6, 6 and the second driving force of the rear wheels 7, 7. Referring to FIG. 5, the eco priority distribution ratio corresponding to the upper limit threshold value of the target driving force determined in STEP 16 is searched.

  Specifically, as shown in FIG. 3A, the front and rear wheel distribution ratio determining unit 3B uses the first driving force of the front wheels 6 and 6 as the vertical axis and the second driving force of the rear wheels 7 and 7 as the horizontal axis. Then, a map with the distance from the origin as the upper limit threshold of the target driving force is referred to.

  FIG. 3A shows a change in road surface friction, but when changing the driving force distribution ratio to the eco priority distribution ratio without changing the upper limit threshold of the target driving force, for example, from the dry road surface at the second position. The map which determines the driving force distribution ratio in case a road surface state changes to the wet road surface of a 1st position is shown.

  In FIG. 3A, a virtual line indicating a position equidistant from the origin indicates a line having a constant upper limit threshold value of the target driving force. A solid line indicates an ideal driving force distribution ratio defined by a vehicle weight distribution ratio (ground load ratio) corresponding to the first friction coefficient μ1, and a broken line indicates a slip corresponding to the first friction coefficient μ1. The limit driving force distribution ratio is shown. That is, in the range between the two broken lines indicating the slip limit, the vehicle does not exceed the slip limit, and the vehicle may slip beyond the slip limit on the outer side.

  In FIG. 3A, the front-rear wheel distribution ratio determining unit 3B determines the slip limit corresponding to the upper limit threshold (here, constant) of the target driving force determined in STEP 16 from the driving force distribution ratio B at the second position. The driving force distribution ratio A is searched as an eco priority distribution ratio.

  Here, the driving force distribution ratio A at the slip limit reduces the energy consumption of the vehicle in that the ratio of the first driving force of the front wheels 6 and 6 is larger than the ideal distribution ratio C defined from the weight distribution ratio. Can be made.

  Next, the front / rear wheel distribution ratio determination unit 3B determines the drive power distribution ratio between the first driving force of the front wheels 6 and 6 and the second driving force of the rear wheels 7 and 7 based on the eco priority distribution ratio searched in STEP 17. Is determined (FIG. 2 / STEP 18).

  The front and rear wheel distribution ratio determination unit 3B may use the eco priority distribution ratio as it is as the driving force distribution ratio between the first driving force and the second driving force, but determines the driving force distribution ratio after performing slip determination. It is desirable.

  In the slip determination, the upper limit driving force of each wheel defined by the first friction coefficient μ1 at the first position is determined from the first driving force of the front wheels 6 and 6 and the first driving force of the rear wheels 7 and 7 obtained from the eco priority distribution ratio. 2. It is performed by determining that the driving force does not exceed.

  As a result of the slip determination, when the upper limit driving force of each wheel exceeds the first driving force of the front wheels 6 and 6 and the second driving force of the rear wheels 7 and 7 obtained from the eco priority distribution ratio, Then, the slip determination is performed again after performing the process of correcting the eco priority distribution ratio to the ideal distribution ratio C defined from the weight distribution ratio or the correction process of reducing the upper limit threshold value of the target driving force.

  If the first driving force of the front wheels 6 and 6 and the second driving force of the rear wheels 7 and 7 obtained from the eco priority distribution ratio do not exceed the upper limit driving force of each wheel, the eco priority distribution ratio Is determined as a driving force distribution ratio of the first driving force and the second driving force.

  Next, the driving force change management unit 3C determines the driving force change timing (FIG. 2 / STEP 19).

  Specifically, the driving force change management unit 3C multiplies the distance from the second position to the first position calculated from the map information of the navigation device (not shown) by the moving speed of the vehicle, thereby predicting the arrival of the first position. Time is calculated, and timing (change start timing and change end timing) is determined so that the driving force distribution ratio between the first driving force and the second driving force is changed before the first position arrival prediction time.

  A time chart of the change timing by the driving force change management unit 3C is schematically shown in FIG. In FIG. 3B, the start and end of the change are determined so that the change from the current driving force distribution ratio B to the driving force distribution ratio A determined in STEP 18 before the first position arrival prediction time is completed. Is done.

  The above is the details of the processing by the main ECU 3. By changing the driving force distribution ratio of STEP 18 determined in this way at the change timing of STEP 19, the road surface state changes from the second position to the first position. Even in the case where there is a slip, the target driving force of the vehicle can correspond to the change in the road surface friction coefficient in advance, and the first driving force and the second driving force can be slipped corresponding to the first position in advance. Can be suppressed. Further, by setting the first driving force and the second driving force to the slip limit or in the vicinity thereof, it is possible to simultaneously realize slip suppression and minimization of vehicle energy consumption.

  In the present embodiment, the vehicle (electric 4WD) including the first motor 11 and the second motor 12 has been described as an example of the vehicle. However, the vehicle on which the power supply system is mounted is not limited to this. As long as the vehicle is propelled by the electric power supplied from the battery 2, it may be a fuel cell vehicle or an electric vehicle provided with power storage means, in addition to a series hybrid vehicle or a parallel hybrid vehicle. Further, in the present embodiment, the case where the front wheels 6 and 6 are the first drive wheels has been described. However, the rear wheels 7 and 7 are the first drive wheels and are driven by the first motor 11 and the engine 1, and the front wheels 6 and 6 are driven. 6 may be driven by the second motor 12 as a second drive wheel.

  In the present embodiment, the first friction coefficient μ1 at the first position and the second friction coefficient μ2 at the second position may be corrected according to the inclination gradient. Specifically, height difference information is added to the map information of the navigation device provided in the vehicle, and when there is an inclination at the first position and the second position, a correction amount corresponding to the inclination is added or subtracted. You may make it do. Furthermore, the correction amount may be changed depending on whether the slope is an upward slope or a downward slope. For example, even if the road surface friction coefficient is the same, in the case of a downward slope, it is possible to cope with a decrease in the critical driving force due to a decrease in the shaft weight on the rear wheels 7 and 7 side. The driving force distribution ratio can be changed in advance in accordance with the change.

  Furthermore, in the present embodiment, the case where the upper limit threshold value of the target driving force is constant and the driving force distribution ratio is changed has been described (FIG. 3). However, the present invention is not limited to this, and FIG. As shown, the eco-priority distribution ratio may be searched and the driving force distribution ratio may be changed while limiting the upper limit threshold value of the target driving force.

  Specifically, in FIG. 4A, the second position is a high μ road (dry road surface) and is not subject to the limit of the slip limit, and from the state B where only the first driving force of the front wheels 6 and 6 is traveling, The upper first position is a low μ road (snowy road) and the upper limit threshold of the target driving force is limited. In this case, the slip limit driving force distribution ratio A corresponding to the limited upper limit threshold of the target driving force (FIG. 2 / STEP 16) is searched as the eco priority distribution ratio. The driving force distribution ratio A at the slip limit can reduce the consumption energy of the vehicle in that the ratio of the first driving force of the front wheels 6 and 6 is larger than the ideal distribution ratio C defined from the weight distribution ratio. The possible points are the same as in the above embodiment.

  A time chart for changing the driving force in this case is schematically shown in FIG. In FIG. 4B, as in the above embodiment, the change from the current driving force distribution ratio B to the driving force distribution ratio A determined in STEP 18 before the first position arrival prediction time is completed. The start and end of the change is determined.

  Further, in the present embodiment, the case where the driving force distribution ratio is not limited by the slip limit at the second position (current time) has been described. However, the present invention is not limited to this, and as shown in FIG. In addition, from the state where the driving force distribution ratio due to the slip limit is already limited at the second position, the eco priority distribution ratio is searched and the driving force distribution ratio is changed while limiting the upper limit threshold of the target driving force. It may be.

  Specifically, in FIG. 5A, from the state where the second position is subjected to the slip limit restriction on the low μ road (wet road surface), the first position on the course is further the target driving force on the low μ road (snowy road). This shows a case where the upper limit threshold is limited. In this case, the slip limit driving force distribution ratio A corresponding to the limited upper limit threshold of the target driving force (FIG. 2 / STEP 16) is searched as the eco priority distribution ratio. The driving force distribution ratio A at the slip limit can reduce the consumption energy of the vehicle in that the ratio of the first driving force of the front wheels 6 and 6 is larger than the ideal distribution ratio C defined from the weight distribution ratio. The possible points are the same as in the above embodiment.

  A time chart for changing the driving force in this case is schematically shown in FIG. In FIG. 5B, as in the above embodiment, the change from the current driving force distribution ratio B to the driving force distribution ratio A determined in STEP 18 before the first position arrival prediction time is completed. The start and end of the change is determined.

  Furthermore, in this embodiment, the case where the upper limit threshold value of the target driving force is constant and the driving force distribution ratio is changed from only the first driving force to the combination of the first and second driving forces has been described (FIG. 3). However, the present invention is not limited to this, as shown in FIG. 6A, from the state where only the rear wheels 7 and 7 are driven (for example, when the rear wheels 7 and 7 are the first driving wheels), In addition, the front wheels 6 and 6 may be driven.

  Specifically, in FIG. 6A, the first position on the course does not receive the upper limit threshold value of the target driving force on the wet road surface from the state where the second position is not subject to the slip limit on the dry road surface. This shows the case where the allocation ratio needs to be changed. In this case, the driving force distribution ratio A at the slip limit with the same target driving force upper limit threshold is searched as the eco priority distribution ratio. The driving force distribution ratio A at the slip limit can reduce the consumption energy of the vehicle in that the ratio of the first driving force of the front wheels 6 and 6 is larger than the ideal distribution ratio C defined from the weight distribution ratio. The possible points are the same as in the above embodiment.

  A time chart for changing the driving force in this case is schematically shown in FIG. In FIG. 6B, as in the above embodiment, the change from the current driving force distribution ratio B to the driving force distribution ratio A determined in STEP 18 before the first position arrival prediction time is completed. The start and end of the change is determined.

  Further, in the present embodiment, after searching for the eco-priority driving force distribution ratio (FIG. 2 / STEP 17), the slip determination is performed to determine the driving force distribution ratio (FIG. 2 / STEP 18). Instead, as shown in FIG. 7, a slip limit is set in consideration of the upper limit driving force of each wheel defined by the first friction coefficient μ1 at the first position. The point where the driving force is maximized may be extracted as the eco priority distribution ratio.

  In FIG. 7, the broken line indicates the case where the first friction coefficient is μ11 and μ12, and the solid line indicates the case where the first friction coefficient μ13. In this case, the relationship is μ11> μ12> μ13, and the smaller the first friction coefficient, the smaller the range that does not exceed the slip limit. Then, by extracting the point where the total driving force is maximum within the slip limit range corresponding to the first friction coefficient as the eco priority distribution ratio, slip determination is omitted, and this eco priority distribution ratio is driven as it is. The force distribution ratio can be set (FIG. 2 / STEP 18).

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Battery, 3 ... Main ECU (driving force control means), 3A ... Target driving force calculation part (total driving force determination means), 3B ... Front-rear wheel distribution ratio determination part (driving force distribution determination means), 3C ... Driving force change management unit, 4 ... Information acquisition unit, 4A ... First information acquisition unit (first acquisition unit), 4B ... Second information acquisition unit (second acquisition unit), 6 ... Front wheel (first drive wheel) ), 7 ... Rear wheels (second drive wheels), 11 ... First motor, 12 ... Second motor, 21 ... First PDU, 22 ... Second PDU, 30 ... Engine ECU, 31 ... First motor ECU, 32 ... First 2 motor EUC, 33 ... battery ECU.

Claims (3)

A first drive wheel that is one of the front wheels or the rear wheels and is driven by one or both of the engine and the first motor, and a second wheel that is a wheel other than the first drive wheels and is driven by the second motor. A vehicle comprising: a driving wheel; and a driving force control means for controlling a first driving force for driving the first driving wheel and a second driving force for driving the second driving wheel,
First acquisition means for acquiring a first friction coefficient that is a road surface friction coefficient at a first position on the path of the vehicle;
Total driving force determining means for determining a target value of the total driving force of the vehicle based on at least the first friction coefficient acquired by the first acquiring means;
In a range that does not become the slip limit corresponding to the first friction coefficient acquired by the first acquisition means, the target value of the total driving force determined by the total driving force determination means is satisfied and the energy consumption is minimized. Driving force distribution determining means for determining a combination of the first driving force and the second driving force as a target value of the first driving force and the second driving force;
The driving force control means includes the first driving force and the second driving force determined by the driving force distribution determining means and the first driving force and the second driving force before the vehicle reaches the first position. A vehicle characterized by changing to a target value of the second driving force. The vehicle according to claim 1,
A second acquisition means for acquiring a second friction coefficient that is a road surface friction coefficient of a second position that is a current position of the vehicle;
The total driving force determining means is configured to calculate the first friction coefficient and the second friction coefficient from the first friction coefficient acquired by the first acquisition means and the second friction coefficient acquired by the second acquisition means. A vehicle that determines a target value of a total driving force of the vehicle according to the first friction coefficient when a deviation from a coefficient exceeds a predetermined threshold. The vehicle according to claim 1 or 2,
The first acquisition means includes: map information of a navigation device mounted on the vehicle; travel history information of a vehicle other than the vehicle on the route; and a road surface that is installed on the route and detects a road surface state. The vehicle according to claim 1, wherein the first friction coefficient is obtained from a part or all of the output information of the detection device.

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