Vehicle control device

Abstract

To provide a vehicle control device that is able to stabilize the behavior of a towing vehicle while allowing for improvement in acceleration performance by the driving force of a vehicle in tow.SOLUTION: When a towing vehicle is in a towing-and-traveling state in which the towing vehicle tows a vehicle in tow, the driving force of the vehicle in tow is limited so that the vehicle in tow that has a driving force source does not push the towing vehicle via a coupler. As a result, the vehicle in tow generates a driving force, so that driving assistance in the towing-and-traveling state can be performed; and, for example, improvements in acceleration performance and hill climbing performance, an increase in towing capacity, extended distance, etc. can be expected. Further, controlling the response of the driving force of the vehicle in tow makes it possible for the vehicle in tow to avoid or prevent pushing the towing vehicle. This makes it possible to stabilize the behavior of the towing vehicle while allowing for improved acceleration performance by the driving force of the vehicle in tow.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that controls the driving force of a towed vehicle. [Background technology]

[0002] There is a well-known vehicle control device equipped with a drive control unit that controls the drive force of a towed vehicle having a drive power source and towed by a towing vehicle via a coupler. For example, Patent Document 1 discloses a control device for coupled vehicles. Patent Document 1 discloses a towing vehicle equipped with a first motor that can be driven by a first battery, and a towed vehicle equipped with a second motor that can be driven by a second battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-184584 Summary of the Invention [Problem to be solved by the invention]

[0004] The driving force response of a vehicle varies depending on the type and combination of driving force sources, and also varies for each vehicle, even among internal combustion engine vehicles and electric vehicles. On the other hand, the towed vehicle's generation of driving force improves acceleration performance during towing, in which the towing vehicle tows the towed vehicle. However, differences in driving force response can lead to situations in which the driving force from the towed vehicle is greater than necessary. Under such circumstances, the towing vehicle's behavior may become unstable and the driver may feel uncomfortable. Significantly reducing the driving force of the towed vehicle can reduce the likelihood of the above-mentioned situation, but it also makes it more difficult to obtain the benefit of improved acceleration performance.

[0005] The present invention was made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can stabilize the behavior of the towing vehicle while enjoying improved acceleration performance due to the driving force of the towed vehicle. [Means for solving the problem]

[0006] The gist of the first invention is (a) a vehicle control device having a drive control unit that controls the drive force of a towed vehicle having a drive power source and towed by a towing vehicle via a coupler, and (b) the drive control unit limits the drive force of the towed vehicle so that the towed vehicle does not push the towing vehicle via the coupler when the towing vehicle is in a towing running state in which it tows the towed vehicle. [Effects of the Invention]

[0007] According to the first aspect of the present invention, when the towing vehicle is in a towing state towing a towed vehicle, the driving force of the towed vehicle is limited so that the towed vehicle, which has a driving force source, does not push the towing vehicle via the coupler. As a result, the towed vehicle generates driving force, providing driving assistance in the towing state, which can be expected to improve acceleration performance and hill-climbing performance, increase towing capacity, and extend distance. Furthermore, by controlling the driving force response of the towed vehicle, the towed vehicle is prevented or suppressed from pushing the towing vehicle. Therefore, the towing vehicle's behavior can be stabilized while enjoying improved acceleration performance due to the driving force of the towed vehicle. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating the schematic configuration of an articulated vehicle to which the present invention is applied, and is also a diagram illustrating the main parts of control functions and control systems for various controls in the articulated vehicle.

[0021] FIG. [Figure 2] FIG. 2 is a diagram illustrating an example of a towing traveling state in which a towing vehicle tows a trailer. [Figure 3]This is a flowchart explaining the main control operations of the vehicle control device, and is a flowchart explaining the control operations for stabilizing the behavior of the towing vehicle while enjoying improved acceleration performance due to the trailer driving force. [Figure 4] 4 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 3 is executed. FIG. [Figure 5] This is a flowchart explaining the main control operations of the vehicle control device, and is a flowchart explaining the control operations for stabilizing the behavior of the towing vehicle while enjoying improved acceleration performance due to the trailer driving force, and is an embodiment different from that of Figure 3. [Figure 6] This is a flowchart explaining the main control operations of the trailer's electronic control device, and explains the control operations for stabilizing the behavior of the towing vehicle while enjoying improved acceleration performance due to the trailer driving force, and is an embodiment different from those of Figures 3 and 5. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0010] Figure 1 is a diagram illustrating the general configuration of an articulated vehicle 10 to which the present invention is applied, and also illustrates the control functions and main parts of the control system for various controls in the articulated vehicle 10. In Figure 1, the articulated vehicle 10 is formed by connecting a towing vehicle 20 and a trailer 60 together.

[0011] The towing vehicle 20 is, for example, a known automobile, and is equipped with an engine 22, a transmission 24, a differential gear 26, a drive shaft 28, drive wheels 30, etc. The engine 22 functions as a driving power source for the towing vehicle 20. The engine torque Te of the engine 22 is controlled by an electronic control device 50, which will be described later. In the towing vehicle 20, power from the engine 22 is transmitted to the drive wheels 30 via the transmission 24, differential gear 26, a pair of drive shafts 28, etc. in this order.

[0012] The trailer 60 is a towed vehicle that is towed by the towing vehicle 20. The trailer 60 is equipped with an electric motor 62, a differential gear 64, a drive shaft 66, drive wheels 68, etc. The electric motor 62 functions as a driving power source for the trailer 60. The electric motor torque Tm of the electric motor 62 is controlled by an electronic control device 80, which will be described later. In the trailer 60, the power from the electric motor 62 is transmitted to the drive wheels 68 via the differential gear 64, the pair of drive shafts 66, etc. in this order. Note that regenerative torque that causes the electric motor torque Tm to become negative may be transmitted to the drive wheels 68 as braking torque.

[0013] FIG. 2 is a diagram showing an example of a towing traveling state in which the towing vehicle 20 tows the trailer 60. FIG. 2(a) is a side view seen from the left in the forward direction. FIG. 2(b) is a plan view seen from above in the vertical direction. In FIG. 2, the trailer 60 is towed by the towing vehicle 20 via a coupler 90. The coupler 90 includes, for example, a trailer hitch member 92 and a vehicle hitch member 94. The trailer hitch member 92 is attached to the front end of the trailer 60. The vehicle hitch member 94 is attached to the rear end of the towing vehicle 20. The trailer hitch member 92 and the vehicle hitch member 94 are connected at a connecting portion 96. The connecting portion 96 is the connecting portion of the trailer 60 connected to the towing vehicle 20, and is the tip of the trailer hitch member 92 on the towing vehicle 20 side. The connecting portion 96 corresponds to the connecting portion between the towing vehicle 20 and the trailer 60. The trailer 60 is towed by the towing vehicle 20 such that the coupling 96 is connected to the vehicle hitch member 94, and the coupler 90 prevents the towing vehicle 20 and the trailer 60 from moving toward or away from each other.

[0014] Returning to Figure 1, the towing vehicle 20 further includes an electronic control unit 50 as a controller related to the control of the engine 22, etc. The electronic control unit 50 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc. The CPU executes various controls of the towing vehicle 20 by, for example, utilizing the temporary storage function of the RAM and performing signal processing in accordance with programs stored in advance in the ROM.

[0015] The electronic control device 50 is supplied with various signals based on detection values ​​from various sensors provided on the towing vehicle 20. The various sensors provided on the towing vehicle 20 include, for example, an engine rotation speed sensor 32, a vehicle speed sensor 34, an accelerator position sensor 36, a throttle valve position sensor 38, and a steering sensor 40. The various signals include, for example, engine rotation speed Ne, vehicle speed Vv, accelerator position θacc, throttle valve position θth, steering angle θsw, and steering direction Dsw. Engine rotation speed Ne is the rotation speed of the engine 22. Vehicle speed Vv is the speed of the towing vehicle 20. Accelerator position θacc is a signal corresponding to the acceleration request amount indicating the magnitude of the acceleration operation by the driver, and is the amount of accelerator operation by the driver. Throttle valve position θth is the opening of the electronic throttle valve. Steering angle θsw is the steering angle of the steering wheel of the towing vehicle 20. The steering direction Dsw is the steering direction of the steering wheel.

[0016] The electronic control device 50 outputs various command signals to each device provided in the towing vehicle 20. The devices provided in the towing vehicle 20 include, for example, the engine 22. The various command signals include, for example, an engine control command signal Se for controlling the engine 22.

[0017] The trailer 60 further includes an electronic control device 80 as a controller related to the control of the electric motor 62. The electronic control device 80 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc. The CPU executes various controls of the trailer 60 by performing signal processing in accordance with a program stored in advance in the ROM while utilizing, for example, the temporary storage function of the RAM.

[0018] The electronic control device 80 is supplied with various signals based on detection values ​​from various sensors provided on the trailer 60. The various sensors provided on the trailer 60 include, for example, a motor rotation speed sensor 70, a vehicle speed sensor 72, and a load sensor 74. The load sensor 74 is a sensor provided on the coupler 90, particularly on the coupling section 96 (see FIG. 2), and is, for example, a strain gauge. The various signals include, for example, the motor rotation speed Nm, the trailer speed Vt, and the hitch load Fx. The motor rotation speed Nm is the rotation speed of the electric motor 62. The trailer speed Vt is the speed of the trailer 60.

[0019] The hitch load Fx is the load on the coupler 90, particularly on the coupling portion 96, and corresponds to the difference between the vehicle driving force Fv and the trailer driving force Ft, taking into account factors such as the steering angle θsw, the weight of the towing vehicle 20, and the weight of the trailer 60 (see FIG. 2). The vehicle driving force Fv is the driving force of the towing vehicle 20. The trailer driving force Ft is the driving force of the trailer 60. When the hitch load Fx is a positive value (Fx>0), the direction of the hitch load Fx is the direction in which the trailer 60 pushes the towing vehicle 20. When the hitch load Fx is a negative value (Fx<0), the direction of the hitch load Fx is the direction in which the trailer 60 does not push the towing vehicle 20, that is, the direction in which the towing vehicle 20 pulls the trailer 60.

[0020] The electronic control device 80 outputs various command signals to each device provided in the trailer 60. The devices provided in the trailer 60 are, for example, the electric motor 62. The various command signals are, for example, an electric motor control command signal Sm for controlling the electric motor 62.

[0021] The electronic control unit 50 and the electronic control unit 80 are connected to each other so that they can communicate with each other, for example, by wire or wirelessly. The electronic control unit 50 and the electronic control unit 80 each function as a vehicle control device 100 that cooperates with each other to perform drive control, for example.

[0022] The electronic control device 50 includes an engine control unit 52 that controls the engine 22 to implement various controls for the towing vehicle 20. The engine control unit 52 calculates a vehicle drive demand Qvdem, which is a drive demand for the towing vehicle 20, by, for example, applying the accelerator opening θacc and the vehicle speed Vv to a vehicle drive demand map MAPv. The vehicle drive demand map MAPv is a predetermined relationship for calculating the vehicle drive demand Qvdem, which is determined and stored in advance, for example, experimentally or through design. The vehicle drive demand Qvdem is, for example, the vehicle drive force Fv required for the towing vehicle 20, i.e., the required vehicle drive force Fvdem at the drive wheels 30. The engine control unit 52 calculates a required engine torque Tedem, which is a required value of the engine torque Te to achieve the vehicle drive demand Qvdem, taking into account, for example, transmission loss, accessory load, and the gear ratio of the transmission 24. The engine control unit 52 outputs an engine control command signal Se that controls the engine 22 to obtain the required engine torque Tedem.

[0023] The electronic control device 80 includes an electric motor control unit 82 that controls the electric motor 62 to implement various controls for the trailer 60. The electric motor control unit 82 calculates the trailer drive demand Qtdem, which is the drive demand for the trailer 60, by applying the accelerator opening θacc and the trailer speed Vt to a trailer drive demand map MAPt, for example. The trailer drive demand map MAPt is, for example, a relationship for calculating a predetermined trailer drive demand Qtdem. The trailer drive demand Qtdem is, for example, the trailer drive force Ft required for the trailer 60, i.e., the required trailer drive force Ftdem at the drive wheels 68. The electric motor control unit 82 calculates the required electric motor torque Tmdem, which is the required value of the electric motor torque Tm required to achieve the trailer drive demand Qtdem, taking into account, for example, transmission loss. The electric motor control unit 82 outputs an electric motor control command signal Sm that controls the electric motor 62 so as to obtain the required electric motor torque Tmdem. In this way, the electric motor control unit 82 functions as a drive control unit that controls the trailer drive force Ft.

[0024] Considering the output characteristics of the engine 22 and the electric motor 62, the responsiveness of the vehicle driving force Fv to the required vehicle driving force Fvdem may be inferior to the responsiveness of the trailer driving force Ft to the required trailer driving force Ftdem. As a result, during acceleration, such as when the accelerator is depressed or increased, the trailer driving force Ft may temporarily become larger than the vehicle driving force Fv, which may result in the trailer 60 pushing the towing vehicle 20 at a single point from the coupling portion 96 via the coupler 90. This may cause the towing vehicle 20 to behave erratically. Unless otherwise specified, the vehicle driving force Fv is synonymous with the actual vehicle driving force Fvr, which is the actual vehicle driving force Fv, and the trailer driving force Ft is synonymous with the actual trailer driving force Ftr, which is the actual trailer driving force Ft.

[0025] Therefore, the electric motor control unit 82 controls the response of the trailer driving force Ft to prevent the trailer 60 from pushing the towing vehicle 20 through the coupler 90. For example, when the towing vehicle 20 is in a towing driving state in which it tows the trailer 60 through the coupler 90, the electric motor control unit 82 limits the trailer driving force Ft so that the trailer 60 does not push the towing vehicle 20 through the coupler 90.

[0026] FIG. 3 is a flowchart illustrating the main control operations of the vehicle control device 100, which are executed repeatedly, for example, to stabilize the behavior of the towing vehicle 20 while enjoying improved acceleration performance due to the trailer driving force Ft.

[0027] 3, first, in step S10a (hereinafter, "step" will be omitted) corresponding to the function of the electronic control unit 50, information such as accelerator opening θacc, steering angle θsw, and steering direction Dsw is acquired. Next, in S20a corresponding to the function of the engine control unit 52 and the electric motor control unit 82, required vehicle driving force Fvdem and required trailer driving force Ftdem are calculated. Next, in S30a corresponding to the function of the engine control unit 52 and the electric motor control unit 82, estimated values ​​of vehicle driving force Fv and trailer driving force Ft are calculated. For example, the estimated value of vehicle driving force Fv is calculated using a predetermined approximation formula that takes into account a response delay to required vehicle driving force Fvdem. Alternatively, the estimated value of vehicle driving force Fv is calculated based on actual engine torque Te. At this time, the steering angle θsw, steering direction Dsw, braking force by wheel brakes, etc. may also be taken into consideration. Furthermore, for example, the estimated trailer driving force Ft is calculated using a predetermined approximation formula that takes into account a response delay with respect to the required trailer driving force Ftdem. Alternatively, the estimated trailer driving force Ft is calculated based on the actual electric motor torque Tm. Next, in S40a, which corresponds to the function of the electric motor control unit 82, a limit trailer driving force Ftlim, which is the limit trailer driving force Ft at which the trailer 60 does not push the towing vehicle 20 via the coupler 90, is calculated based on the estimated vehicle driving force Fv. For example, a limit trailer driving force Ftlim, which is the upper limit of the range of trailer driving force Ft at which the hitch load Fx becomes a negative value in calculation, is calculated based on the estimated vehicle driving force Fv. Next, in S50a, which corresponds to the function of the electric motor control unit 82, the required trailer driving force Ftdem is limited to the limit trailer driving force Ftlim. In other words, if the required trailer driving force Ftdem exceeds the limit trailer driving force Ftlim, the required trailer driving force Ftdem is set to the limit trailer driving force Ftlim. Next, in S60a, which corresponds to the function of the electric motor control unit 82, the electric motor 62 is controlled using the required trailer driving force Ftdem, which is upper-bounded by the limit trailer driving force Ftlim, to drive the trailer 60. In other words, the upper-bound required trailer driving force Ftdem is reflected in the trailer driving force Ft.

[0028] In this way, the motor control unit 82 calculates the limit trailer driving force Ftlim, which is the upper limit of the range of trailer driving force Ft at which the trailer 60 does not push the towing vehicle 20, based on the vehicle driving force Fv, and limits the trailer driving force Ft using the limit trailer driving force Ftlim. The limit trailer driving force Ftlim is also the upper limit of the range of trailer driving force Ft at which the hitch load Fx is less than the load in the direction in which the trailer 60 pushes the towing vehicle 20.

[0029] FIG. 4 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 3 is executed. FIG. 4 shows an example of the case when starting or accelerating. In FIG. 4, time t1 indicates the time when the accelerator is pressed down or the accelerator is increased. In the comparative example shown by the dashed line, the trailer driving force Ft is generated with better responsiveness than the vehicle driving force Fv. Under such circumstances, the trailer 60 tends to push the towing vehicle 20. In contrast, in the present embodiment shown by the two-dot chain line, the trailer driving force Ft is limited by the limit trailer driving force Ftlim, so a situation in which the trailer 60 pushes the towing vehicle 20 is avoided or suppressed.

[0030] As described above, according to this embodiment, the trailer 60 is equipped with the electric motor 62 as a driving force source. As a result, the trailer 60 generates the trailer driving force Ft, which provides driving assistance when the towing vehicle 20 is towing the trailer 60. This can be expected to improve acceleration performance and hill-climbing performance, increase towing capacity, and extend distance, for example. In addition, when in the towing state, the trailer driving force Ft is limited so that the trailer 60 does not push the towing vehicle 20 via the coupler 90. This controls the response of the trailer driving force Ft, thereby preventing or suppressing the trailer 60 from pushing the towing vehicle 20. Therefore, it is possible to stabilize the behavior of the towing vehicle 20 while enjoying the improved acceleration performance provided by the trailer driving force Ft.

[0031] Furthermore, according to this embodiment, the limit trailer driving force Ftlim is calculated based on the vehicle driving force Fv, and the trailer driving force Ft is limited by this limit trailer driving force Ftlim. The limit trailer driving force Ftlim is the upper limit of the range of trailer driving force Ft at which the hitch load Fx is less than the load in the direction in which the trailer 60 pushes the towing vehicle 20. This appropriately limits the trailer driving force Ft so that the trailer 60 does not push the towing vehicle 20 when in towing mode.

[0032] Next, another embodiment of the present invention will be described. In the following description, parts common to the embodiments will be given the same reference numerals and the description thereof will be omitted. [Example]

[0033] In the first embodiment described above, the trailer driving force Ft is limited by calculating the limit trailer driving force Ftlim. In this embodiment, the trailer driving force Ft is limited depending on the direction of the hitch load Fx.

[0034] 5 is a flowchart illustrating the main control operations of the vehicle control device 100, which are executed repeatedly, for example, to stabilize the behavior of the towing vehicle 20 while improving acceleration performance due to the trailer driving force Ft. FIG. 5 is an embodiment different from the flowchart of FIG.

[0035] In Figure 5, S10b-S30b are the same as S10a-S30a in Figure 3, and therefore a description thereof will be omitted. Following S30b, in S40b, which corresponds to the function of the electric motor control unit 82, the hitch load Fx is calculated using the steering angle θsw, the steering direction Dsw, the estimated vehicle driving force Fv, the estimated trailer driving force Ft, and the like, and the direction of the hitch load Fx is obtained. Then, it is determined whether the direction of the hitch load Fx is the direction in which the trailer 60 pushes the towing vehicle 20. Note that in S40b, the hitch load Fx, which is the detection signal of the load sensor 74, may be used. If the determination in S40b is positive, in S50b, which corresponds to the function of the electric motor control unit 82, the required trailer driving force Ftdem is subtracted. For example, the required trailer driving force Ftdem is subtracted by feedback control so that the hitch load Fx is less than the load in the direction in which the trailer 60 pushes the towing vehicle 20. Alternatively, the required trailer driving force Ftdem is subtracted in accordance with the hitch load Fx, and the greater the hitch load Fx, the more the required trailer driving force Ftdem is reduced. If the determination in S40b above is negative, or following S50b above, in S60b, which corresponds to the function of the electric motor control unit 82, the electric motor 62 is controlled using the required trailer driving force Ftdem to drive the trailer 60. If the determination in S40b above is negative, the required trailer driving force Ftdem calculated in S20b above is used as is and reflected in the trailer driving force Ft. If the determination in S40b above is positive, the required trailer driving force Ftdem subtracted in S50b above is used and reflected in the trailer driving force Ft.

[0036] In this way, the electric motor control unit 82 obtains the direction of the hitch load Fx and limits the trailer driving force Ft so that the direction of the hitch load Fx is a direction in which the trailer 60 does not push the towing vehicle 20 .

[0037] As described above, according to this embodiment, similar to the first embodiment, it is possible to stabilize the behavior of the towing vehicle 20 while enjoying the benefits of improved acceleration performance due to the trailer driving force Ft.

[0038] Furthermore, according to this embodiment, the direction of the hitch load Fx is acquired, and the trailer driving force Ft is limited so that the direction of the hitch load Fx is a direction in which the trailer 60 does not push the towing vehicle 20. As a result, when in towing travel mode, the trailer driving force Ft is appropriately limited so that the trailer 60 does not push the towing vehicle 20. [Example]

[0039] In the first and second embodiments described above, the electronic control unit 50 and the electronic control unit 80 each function as a vehicle control device 100 that cooperates to perform drive control. In this embodiment, the electronic control unit 80 limits the trailer driving force Ft independently without coordinating with the electronic control unit 50. Therefore, in this embodiment, the hitch load Fx, which is the detection signal of the load sensor 74, is used to limit the trailer driving force Ft.

[0040] Figure 6 is a flowchart illustrating the main control operations of the electronic control unit 80, which are executed repeatedly, for example, to stabilize the behavior of the towing vehicle 20 while improving acceleration performance due to the trailer driving force Ft. Figure 6 illustrates an embodiment different from the flowcharts of Figures 3 and 5. The flowchart of Figure 6 can be completed by the electronic control unit 80 alone.

[0041] In FIG. 6, each step in the flowchart corresponds to a function of the electric motor control unit 82. In S10c, the required trailer driving force Ftdem is calculated. In S10c, the accelerator opening θacc is not used, and the required trailer driving force Ftdem is calculated based on, for example, the trailer speed Vt to resist the traveling resistance of the trailer 60. Next, in S20c, information on the hitch load Fx, which is a detection signal from the load sensor 74, is acquired. Next, in S30c, it is determined whether the direction of the hitch load Fx is the direction in which the trailer 60 pushes the towing vehicle 20. If the determination in S30c is positive, S40c is executed. Since S40c is the same as S50b in FIG. 5, its description is omitted. If the determination in S30c is negative, or following S40c, in S50c, the electric motor 62 is controlled using the required trailer driving force Ftdem to drive the trailer 60. If the determination in S30c above is negative, the required trailer driving force Ftdem calculated in S10c above is used as is and reflected in the trailer driving force Ft. If the determination in S30c above is positive, the required trailer driving force Ftdem subtracted in S40c above is used and reflected in the trailer driving force Ft.

[0042] In this way, the motor control unit 82 obtains the hitch load Fx and the direction of the hitch load Fx from the load sensor 74, and limits the trailer driving force Ft if the direction of the hitch load Fx is the direction in which the trailer 60 pushes the towing vehicle 20. When limiting the trailer driving force Ft, the motor control unit 82 increases the amount by which the trailer driving force Ft is reduced the greater the hitch load Fx.

[0043] As described above, according to this embodiment, similar to the first embodiment, it is possible to stabilize the behavior of the towing vehicle 20 while enjoying the improved acceleration performance due to the trailer driving force Ft.

[0044] Furthermore, according to this embodiment, the hitch load Fx and the direction of the hitch load Fx are acquired by the load sensor 74, and if the direction of the hitch load Fx is such that the trailer 60 is pushing the towing vehicle 20, the trailer driving force Ft is limited. When limiting the trailer driving force Ft, the greater the hitch load Fx, the greater the amount by which the trailer driving force Ft is reduced. This ensures that the trailer driving force Ft is appropriately limited so that the trailer 60 does not push the towing vehicle 20 when in towing travel mode. Furthermore, the trailer driving force Ft can be limited by the trailer 60 alone so that the trailer 60 does not push the towing vehicle 20.

[0045] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0046] For example, in the above-described first to third embodiments, a strain gauge was used as the load sensor 74, but this is not a limitation. For example, the sensor provided in the connecting portion 96 may be a load cell other than a strain gauge, or a displacement sensor, as long as it can detect the hitch load Fx and the direction of the hitch load Fx. With a displacement sensor, the hitch load Fx and the direction of the hitch load Fx are calculated from the amount of displacement, for example. Note that in the above-described first and second embodiments, the trailer driving force Ft can be limited without using the hitch load Fx, which is the detection signal of the load sensor 74, and therefore the load sensor 74 may not be provided.

[0047] Furthermore, in the above-described Examples 1-3, the power source provided in the towing vehicle 20 may be, for example, an electric motor instead of or in addition to the engine 22. Furthermore, the transmission 24 may be, for example, a known planetary gear automatic transmission, a known belt-type continuously variable transmission, a known synchromesh parallel two-shaft automatic transmission, a known electric continuously variable transmission, or a known synchromesh parallel two-shaft manual transmission. Note that if the power source provided in the towing vehicle 20 is an electric motor, the towing vehicle 20 does not need to be provided with a transmission 24.

[0048] Furthermore, in the above-described Examples 1-3, when the combination vehicle 10 turns, an assist force from the trailer 60 is applied in a direction slightly offset from the forward / reverse direction of the towing vehicle 20, which may result in an assist force acting in an unintended direction (see FIG. 2(b)). For this reason, it is particularly useful to implement the present invention when turning.

[0049] In the third embodiment, the manner (degree) of pulling during towing may be estimated, for example, from the trailer speed Vt relative to the trailer driving force Ft, and the hitch load Fx and the direction of the hitch load Fx may be estimated from the manner of pulling. In this case, the load sensor 74 may not be provided.

[0050] Furthermore, in the above-described third embodiment, since the trailer 60 alone can limit the trailer driving force Ft, the vehicle control device 100 only needs to include at least the electronic control device 80. Furthermore, the electronic control device 50 and the electronic control device 80 do not need to be communicatively connected.

[0051] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0052] 20: Towing vehicle 50: Electronic control device (vehicle control device) 60: Trailer (towed vehicle) 62: Electric motor (driving force source) 74: Load sensor (sensor) 80: Electronic control device (vehicle control device) 82: Electric motor control unit (drive control unit) 90: Coupler

Claims

1. A vehicle control device including a drive control unit that controls the drive force of a towed vehicle having a drive force source and towed by a towing vehicle via a coupler, The vehicle control device is characterized in that the drive control unit limits the drive force of the towed vehicle so that the towed vehicle does not push the towing vehicle via the coupler when the towing vehicle is in a towing running state in which it tows the towed vehicle.

2. 2. The vehicle control device according to claim 1, wherein the drive control unit calculates an upper limit value of a drive force range of the towed vehicle at which the towed vehicle does not push the towing vehicle, based on the drive force of the towing vehicle, and limits the drive force of the towed vehicle based on the upper limit value.

3. 3. The vehicle control device according to claim 2, wherein the upper limit value is an upper limit value of a driving force range of the towed vehicle at which the load on the coupler is less than the load in the direction in which the towed vehicle pushes the towing vehicle.

4. 2. The vehicle control device according to claim 1, wherein the drive control unit acquires the direction of the load on the coupler and limits the drive force of the towed vehicle so that the direction of the load is a direction in which the towed vehicle does not push the towing vehicle.

5. The vehicle control device according to claim 1, characterized in that the drive control unit acquires the load and the direction of the load on the coupler using a sensor provided on the coupler, and if the direction of the load is in the direction in which the towed vehicle is pushing the towing vehicle, limits the drive force of the towed vehicle, and the greater the load, the greater the amount by which the drive force of the towed vehicle is reduced.

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