JP5999329B2 - Trailer vehicle slope start assist device - Google Patents

Description

  The present invention relates to a slope start assist device for a trailer vehicle, and more specifically, a road surface gradient estimated by a detecting means provided on a tractor side when the vehicle is held in a braking state during a temporary stop on an uphill road and then starts. TECHNICAL FIELD The present invention relates to a trail start assist device for a trailer vehicle that automatically releases braking at a timing based on the above.

Conventionally, in order to eliminate the troublesome braking operation when starting a hill, a vehicle equipped with a hill starting assistance device that automatically activates and stops the braking device of the vehicle when temporarily stopping on an uphill road has been put into practical use. ing. This type of slope start assist device, for example, by shutting off the brake hydraulic line when the vehicle is stopped, keeps the hydraulic line at a high pressure even after the driver's braking operation is stopped, and then starts the braking. The hydraulic line is sometimes opened to release the braking (see, for example, Patent Document 1).
The brake release timing is important for smoothly starting the vehicle on an uphill road.If the brake release timing is too early, the vehicle will move backward, and conversely if the brake release timing is too late, the driving force and braking force This causes a wasteful fuel consumption. In the technique of Patent Document 1, the brake release timing is determined based on the road surface gradient and the air pressure change of the air suspension. With regard to the road surface gradient, in consideration of the fact that it is easy for rearward slip of the vehicle to occur in a steep gradient, the braking is continued until the driving force sufficiently increases by delaying the timing of brake release as the road surface gradient is steep. Yes. For example, the road surface gradient is estimated during traveling until the vehicle stops based on detection information of an acceleration sensor mounted on the vehicle.

JP 2003-81072 A

By the way, the uphill road on which the vehicle stops is not limited to a single road surface gradient, but may stop over two different road surface gradients as shown in FIG. 9, for example. Since a general vehicle stops with an attitude obtained by averaging these two kinds of road surface gradients, for example, it is possible to determine an appropriate brake release timing based on the road surface gradient estimated from the detection information of the acceleration sensor. There is no problem.
However, in the trailer vehicle, the tractor A on the towing side and the trailer B on the towed side are connected so that the angle can be changed in the pitching direction, the yawing direction, and the rolling direction. For this reason, when the vehicle stops over two different road surface gradients, the tractor A side and the trailer B side take different postures in the pitching direction, and the road surface gradients are different from each other. Since this type of trailer vehicle employs an operation mode in which the trailer B requested to be transported is connected to the tractor A to pull and travel, the acceleration sensor is provided on the tractor A side as a main body.

For this reason, the gradient of the road surface on which the tractor A side is located is estimated as the road surface gradient of the entire trailer vehicle based on the attitude in the pitching direction on the tractor A side, and no consideration is given to the road surface gradient on which the trailer B side is located. Therefore, the technique of Patent Document 1 causes a problem that braking is released at an incorrect timing due to an inappropriate estimation of the road surface gradient.
For example, as shown in FIG. 9, when the vehicle is stopped with the tractor A side positioned on a flat road, a gentle road gradient (approximately 0) is estimated from the detection information of the acceleration sensor, but the road gradient received by the entire vehicle is Since it is sudden, the timing of releasing the brake is too early.

As described above, the technique of Patent Document 1 does not consider the special circumstances of the trailer vehicle, and therefore has a problem that it is impossible to realize an appropriate estimation of the road surface gradient, and consequently, a brake release at an appropriate timing.
As a countermeasure, it is conceivable to provide an acceleration sensor on the trailer B side. However, since the trailer vehicle is in the operation mode as described above, the trailer B connected to the tractor A cannot be specified, and it is practically impossible to equip all the trailers B on the market with an acceleration sensor. . Therefore, a drastic measure has been demanded from the past.
The present invention has been made to solve such problems. The object of the present invention is to provide a road surface estimated by detection means provided on the tractor side without providing detection means such as an acceleration sensor on the trailer side. It is an object of the present invention to provide a trail start assist device for a trailer vehicle capable of releasing braking holding accompanying stopping on an uphill road at an appropriate timing.

In order to achieve the above object, the invention according to claim 1 is a trailer in which a tractor on a towing side on which a power source for traveling is mounted and a trailer on a towed side on which a load is loaded are connected so that the angle can be arbitrarily changed. in the vehicle, a road surface gradient estimating means for estimating a gradient of a road surface on which the tractor based on detection information of the detecting means provided on the tractor side is located, and the vehicle weight estimation unit Ru estimated Teisu the weight of the trailer vehicle, a trailer Measuring means for measuring the travel distance of the trailer vehicle during traveling of the vehicle, and first determination in which the estimated road surface gradient by the road surface gradient estimating means is set as a threshold based on the vehicle weight by the vehicle weight estimating means during travel of the trailer vehicle When the value exceeds the value, the low gear side slope shift stage is selected as the starting stage, and then the estimated road surface gradient is reduced to less than the first judgment value before measurement by the measuring means. A starting stage selecting means for selecting a high gear side flat road shift stage as a starting stage when it is determined that the moving distance of the trailer vehicle has reached a preset movement determination value, and a braking device when the trailer vehicle stops Is operated to hold the trailer vehicle in a braking state, and the braking start assisting means for releasing the braking of the braking device at the subsequent start, and the braking release timing by the slope starting assisting means based on the starting stage selected by the starting stage selecting means And a brake release timing setting means for delaying the brake release timing when the slope shift speed is selected as the start speed compared to when the flat road shift speed is selected.
Further, the movement determination value is set as the wheel base of the trailer vehicle, the start stage selection means determines the selection of the flat road speed stage based on the movement determination value, and the brake is released based on the start stage selected by the start stage selection means. The timing setting means sets the brake release timing.

According to a second aspect of the present invention, there is provided a trailer vehicle in which a tractor on a traction side on which a driving power source is mounted and a trailer on a towed side on which a load is loaded are connected so that the angle can be arbitrarily changed. Road surface gradient estimating means for estimating the gradient of the road surface on which the tractor is located, vehicle weight estimating means for estimating the weight of the trailer vehicle, and movement of the trailer vehicle during travel of the trailer vehicle A measuring means for measuring a distance, and a start stage when the estimated road surface gradient by the road surface gradient estimating means becomes equal to or greater than a first determination value set as a threshold based on the vehicle weight by the vehicle weight estimating means during travel of the trailer vehicle The low-gear-side slope shift speed is selected as follows, and then the trailer vehicle is moved based on the measurement by the measuring means after the estimated road surface gradient is lowered to less than the first judgment value. When it is determined that the separation has reached a preset movement determination value, start stage selection means for selecting the high gear side flat road shift stage as the start stage, and a brake device is operated when the trailer vehicle is stopped to operate the trailer A slope start assist means for releasing the braking of the braking device at the time of starting after the vehicle is held, and a brake release timing by the slope start assist means are calculated based on the start stage selected by the start stage selecting means, And a brake release timing setting means for delaying the brake release timing when the slope shift speed is selected as the stage, compared to when the flat road shift speed is selected. When the trailer vehicle moves backward during the measurement, the reverse distance is subtracted from the movement distance, and the starting stage selection means determines the selection of the flat road speed stage based on the movement distance after the subtraction. Brake release timing setting means based on the start gear selected by start gear selection means in which to set the brake release timing.

According to a third aspect of the present invention, in the first or second aspect , when the braking release timing setting means selects the flat road shift stage by the start stage selection means, the brake release timing is set in advance corresponding to the flat road shift stage. The early timing is set, and when the slope shift stage is selected, the brake release timing is set to a late timing set in advance corresponding to the slope shift stage.

According to a fourth aspect of the present invention, in the third aspect , the first gear on the low gear side can be switched using the second determination value, which is set to a value closer to the steep slope than the first determination value, as the boundary. The start stage selecting means selects the first slope shift stage as the start stage when the estimated road surface gradient is equal to or higher than the second determination value, and includes the estimated road surface gradient. Is less than the second determination value, the second slope shift stage is selected as the starting stage, and then, after the estimated road surface gradient has decreased below the first determination value, it is determined that the movement distance has reached the movement determination value. When the starting speed is selected, the flat speed is selected, and when the braking release timing setting means selects the second slope speed by the starting speed selection means, the braking release timing is set in advance corresponding to the second slope speed. The first slope shift stage with early timing Upon selection, it is an advance first grade gear position timing of late set corresponding to the brake release timing.

According to a fifth aspect of the present invention, in the first to fourth aspects, the first determination value is a first downside determination value that is set in advance as a steep slope value, and a gentle slope side value. The start stage selection means selects the slope shift stage based on the first down side determination value, and selects the flat road shift stage based on the first up side determination value. .
According to a sixth aspect of the present invention, in the first to fifth aspects, when the ignition switch of the trailer vehicle is turned off, the storage means stores the gear stage selected as the starting stage by the starting stage selecting means at that time. The start gear selection means selects the gear position stored in the storage means as the start gear when the ignition switch is turned on.

  As described above, according to the trail start assist device for a trailer vehicle according to the first aspect of the present invention, when the trailer vehicle is running, when the estimated road surface gradient becomes equal to or greater than the first determination value based on the vehicle weight, the start stage And then select the flat road shift stage as the starting stage when the travel distance of the trailer vehicle reaches the movement determination value after the estimated road surface gradient drops below the first determination value. On the other hand, when the trailer vehicle is stopped, it is held in the braking state by the braking device, and the braking is released at the subsequent start, and the braking release timing at this time is compared with that at the time of selecting the flat road gear stage when selecting the slope gear stage. Delayed.

During the period from when the tractor side enters the uphill road until the tractor side leaves the uphill road and travels by the movement judgment value, at least one of the tractor side or the trailer side is affected by the road slope of the uphill road, At this time, the low gear-side slope shift stage is selected as the start stage. Further, before and after the above period, neither the tractor side nor the trailer side is affected by the road surface gradient, and the high gear side flat road shift stage is selected as the starting stage.
On the other hand, when the trailer vehicle stops on the uphill road, the braking state is maintained by the braking device, and the braking of the braking device is released at the subsequent start. Since the start stage is selected reflecting the vehicle weight and the slope of the uphill road as described above, the brake release timing can be appropriately set according to the start stage. As a result, without holding detection means such as an acceleration sensor on the trailer side, it is possible to release braking holding accompanying stopping on an uphill road at an appropriate timing based on the road surface gradient estimated by the detection means equipped on the tractor side. it can.

Furthermore, according to the hill-start assist of the trailer vehicle of the invention of claim 1, pressurized strong point, the movement determination values were set as the wheel base of the trailer vehicle.
If the tractor side runs away from the uphill road and travels as much as the wheelbase, it can be assumed that the trailer side has also left the uphill road following the tractor. Therefore, the slope road speed and the flat road speed can be selected more accurately, and the braking can be released at an appropriate timing.
According to hill-start assist of the trailer vehicle of the invention of claim 2, when the trailer vehicle is moved backward during the measurement of the moving distance of the trailer vehicle, and to subtract the reverse distance from the moving distance.
Therefore, an appropriate moving distance can be calculated even when the tractor temporarily moves backward after leaving the uphill road. Therefore, the slope road speed and the flat road speed can be selected more accurately, and the braking can be released at an appropriate timing.

According to the slope start assist device for a trailer vehicle of the invention of claim 3 , in addition to claim 1 or 2 , when selecting a flat road shift stage, the brake release timing is set to an early timing corresponding to the flat road shift stage, When selecting the slope shift speed, the timing is delayed corresponding to the slope shift speed.
Accordingly, it is possible to set an appropriate brake release timing according to the selected start stage, and thus release the brake at an appropriate timing.

According to a slope start assist device for a trailer vehicle according to a fourth aspect of the present invention, in addition to the third aspect , the first shift position on the low gear side and the first gear position on the high gear side with the second determination value as a boundary. The first slope shift stage is selected when the road slope is equal to or greater than the second judgment value, and the second slope shift stage is selected when the estimated road slope is less than the second judgment value. When the second slope shift stage is selected, the braking release timing is set to an earlier timing corresponding to the second slope shift stage, and when the first slope shift stage is selected, the later timing corresponding to the first slope shift stage is set. I tried to do it.
Therefore, since the starting stage is selected more finely according to the slope of the uphill road, the braking release timing is also set finely according to the starting stage, so it is appropriate based on each slope gear stage when stopping on the uphill road The brake can be released at a proper timing.

According to the slope start assisting device for a trailer vehicle of the fifth aspect of the invention, in addition to the first to fourth aspects, the slope shift stage is selected based on the first down-side determination value on the steep slope side, and on the gentle slope side. The flat road speed is selected based on the first up-side determination value.
Therefore, even when the slope of the uphill road is uneven and the estimated road surface slope frequently changes as the vehicle travels, it is possible to prevent the slope road speed and the flat road speed from being alternately repeated. Therefore, even in such a road surface condition, an appropriate start stage can be selected, and braking can be released at an appropriate timing based on the selected shift stage.

According to the automatic start stage selection apparatus for a trailer vehicle of claim 6 , in addition to claims 1 to 5, the start stage is stored when the ignition switch is turned off and stored when the ignition switch is turned on. The stage was selected.
Accordingly, it is possible to select an appropriate start stage from the beginning when the ignition switch is turned on, and to release braking at an appropriate timing based on the selected shift stage.

It is a whole lineblock diagram showing the drive system of the trailer vehicle to which the slope start auxiliary device of an embodiment was applied. It is a front view which shows the trailer vehicle when it stops on the road surface of a single gradient. It is explanatory drawing which shows the control map for selecting a start stage. It is a flowchart which shows the starting stage selection / cancellation | release timing setting routine which ECU performs. It is a flowchart which shows the starting stage selection / cancellation | release timing setting routine which ECU performs. It is explanatory drawing which shows the estimation condition of the road surface gradient when the trailer vehicle is drive | working the flat road. It is explanatory drawing which shows the estimation condition of a road surface gradient when a trailer vehicle approaches an uphill road. It is explanatory drawing which shows the estimation condition of a road surface gradient when a trailer vehicle transfers to an uphill road completely. It is explanatory drawing which shows the estimation condition of the road surface gradient when a trailer vehicle approaches the flat road. It is explanatory drawing which shows the estimation condition of a road surface gradient when a trailer vehicle transfers to a completely flat road. It is a flowchart which shows the starting stage selection / cancellation | release timing setting routine which ECU of another example performs.

Hereinafter, an embodiment of a trail start assist device for a trailer vehicle embodying the present invention will be described.
FIG. 1 is an overall configuration diagram showing a drive system of a trailer vehicle to which a slope start assist device of the present embodiment is applied, and FIG. 2 is a front view showing an appearance of the trailer vehicle.
As shown in FIG. 2, the trailer vehicle (hereinafter sometimes referred to simply as a vehicle) changes the angle of the tractor A on the towing side and the trailer B on the towed side arbitrarily in the yawing direction, the pitching direction, and the rolling direction as a whole. It is configured to be connected so as to obtain. A diesel engine (hereinafter referred to as an engine) 1 that is a power source for traveling is mounted on the tractor A side, and the engine driving force is transmitted to the rear wheel Aa of the tractor A through a drive system described below for rotational driving. Thus, the tractor A alone can travel. On the other hand, the trailer B is a vehicle that is not self-propelled with a loaded container, and the transportation of the trailer B is the role of the tractor A. For this reason, the trailer vehicle employs an operation mode in which the trailer B requested to be transported is connected to the tractor A to pull and travel.

  Next, the configuration of the drive system including the engine 1 on the tractor A side will be described. As shown in FIG. 1, an input shaft 3 a of an automatic transmission (hereinafter simply referred to as a transmission) 3 is connected to an output shaft 1 b of the engine 1 via a clutch device 2, and the engine 1 is connected when the clutch device 2 is connected. The rotation is transmitted to the transmission 3. The transmission 3 is based on a manual transmission having six forward speeds and one reverse speed. As described below, the gear shifting operation and the connecting / disconnecting operation of the clutch device 2 accompanying the gear shifting are automated. It is a thing.

The clutch device 2 is configured as a friction clutch that is connected to the flywheel 4 by press-contacting the clutch plate 5 with a pressure spring 6 and is disconnected by separating the clutch plate 5 from the flywheel 4. An air cylinder 8 is connected to the clutch plate 5 via an outer lever 7, and an air tank 11 filled with compressed air is connected to the air cylinder 8 via an air passage 10 in which an electromagnetic valve 9 is interposed.
When the electromagnetic valve 9 is opened, compressed air is supplied from the air tank 11 to the air cylinder 8 via the air passage 10, and the air cylinder 8 is activated to separate the clutch plate 5 from the flywheel 4 via the outer lever 7. Thus, the clutch device 2 is switched from the connected state to the disconnected state. On the other hand, when the solenoid valve 9 is closed, the air cylinder 8 stops operating due to the stop of the supply of compressed air, so that the clutch plate 5 is pressed against the flywheel 4 by the pressure spring 6, and thereby the clutch device 2 is released from the disconnected state. Switch to connected state. As described above, the air cylinder 8 is operated in accordance with the opening and closing of the electromagnetic valve 9 so that the clutch device 2 can be automatically connected and disconnected.

  The transmission 3 is provided with a gear shift unit 14 for switching the gear stage. Although not shown, the gear shift unit 14 includes a plurality of air cylinders that operate shift forks corresponding to the respective gear stages in the transmission 3, and It incorporates multiple solenoid valves that actuate the air cylinder. The gear shift unit 14 is connected to the above-described air tank 11 through the air passage 12, and compressed air from the air tank 11 is supplied to the corresponding air cylinder according to opening and closing of each solenoid valve, and the air cylinder is operated. When the corresponding shift fork is switched, the gear position of the transmission 3 is switched according to the switching operation. As described above, the air cylinder is operated in accordance with the opening / closing of the electromagnetic valve of the gear shift unit 14, and the transmission 3 can be automatically operated for shifting.

In the passenger compartment, an input / output device (not shown), a storage device (ROM, RAM, etc.) for storing control programs and control maps, an ECU (control unit) equipped with a central processing unit (CPU), a timer counter, etc. 21 is installed, and comprehensive control of the engine 1, the clutch device 2, and the transmission 3 is performed.
On the input side of the ECU 21 are an engine rotation speed sensor 22 that detects the rotation speed Ne of the engine 1, a clutch rotation speed sensor 23 that detects the rotation speed (clutch rotation speed Nc) of the input shaft 3a of the transmission 3, and a driver's seat. A lever position sensor 24 that detects the switching position of the provided change lever 13, a gear position sensor 25 that detects the gear position of the transmission 3, an accelerator sensor 27 that detects an operation amount θacc of the accelerator pedal 26, and an output of the transmission 3 A vehicle speed sensor 28 provided on the shaft 3b for detecting the output shaft rotation speed Vss (correlating with the vehicle speed V), a brake switch 30 for detecting the operation of the foot brake 29, and a stroke sensor 31 for detecting the clutch stroke ST of the clutch device 2. And a sensor such as an acceleration sensor 33 (detection means) mounted on the tractor A for detecting the longitudinal acceleration Gs. Sensors are connected.

  Further, the electromagnetic valve 9 of the clutch device 2, the electromagnetic valves of the gear shift unit 14, the braking device 34, etc. are connected to the output side of the ECU 21. It is connected. In addition, you may make it provide ECU for exclusive use of engine control separately from ECU21, for example, without controlling comprehensively by single ECU21 in this way.

  For example, the ECU 21 calculates a fuel injection amount to each cylinder of the engine 1 from a map (not shown) based on the engine rotation speed Ne detected by the engine rotation speed sensor 22 and the accelerator operation amount θacc detected by the accelerator sensor 27. At the same time, the fuel injection timing is calculated from a map (not shown) based on the engine rotational speed Ne and the fuel injection amount. Based on these calculated values, the engine 1 is operated while driving the fuel injection valves of the respective cylinders.

  The ECU 21 executes the automatic shift mode when the lever position sensor 24 detects that the change lever 13 is switched to the D range. Based on the accelerator operation amount θacc and the vehicle speed V detected by the vehicle speed sensor 28, the ECU 21 The target gear position is calculated from the shift map that is not. Then, while opening and closing the electromagnetic valve 9 of the clutch device 2 and connecting and disconnecting the clutch device 2 by the air cylinder 8, the predetermined electromagnetic valve of the gear shift unit 14 is opened and closed and the corresponding shift fork is switched by the air cylinder. Thus, the shift stage is switched to the target shift stage, and thereby the vehicle is always driven with an appropriate shift stage.

On the other hand, the ECU 21 executes a road surface gradient estimation process for estimating the road surface gradient θ while the trailer vehicle is traveling, as will be described later, and uses the estimated road surface gradient θ for automatic start stage selection control and slope start assistance control. ing.
The road surface gradient θ estimation processing is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-097945. For this reason, only a brief description will be given. According to the technique of the publication, the longitudinal acceleration Gv actually generated in the vehicle is obtained from the vehicle speed V detected by the vehicle speed sensor 28 and detected by the longitudinal acceleration Gv and the acceleration sensor 33. A road surface gradient θ is estimated based on the longitudinal acceleration Gs (road surface gradient estimating means).

Since the automatic selection control of the starting stage is well known, only the outline will be described here. The starting stage automatic selection control is a function for selecting an optimum starting stage according to the road surface gradient θ and the vehicle weight. First, the current vehicle weight (the weight of the tractor A + trailer B) is estimated, and the start stage is selected based on the vehicle weight and the road surface gradient θ (start stage selection means). In the present embodiment, the first to third speeds of the transmission are set in advance as the starting speed, and any of these speeds is selected.
The selected start stage is applied at the start after the trailer vehicle is stopped. This makes it possible to start smoothly and quickly even on an uphill or the like where it is easy to stick. The vehicle weight estimation process is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-340165, and thus will not be described in detail. For example, the vehicle weight may be estimated from the vehicle driving torque and the vehicle acceleration (vehicle weight estimation). means).

Further, in the slope start assist control, the braking device 34 is operated when the vehicle is temporarily stopped on the uphill road to hold the vehicle in a braking state, and the braking device 34 is stopped when the vehicle is started by depressing the accelerator to release the braking state. This is a function (slope start assisting means) that eliminates the troublesome brake operation when starting on an uphill road.
Specifically, by interrupting the hydraulic line of the braking device 34 during a temporary stop, the brake continues to be braked while maintaining the hydraulic pressure increased by the brake operation even after the driver's brake operation is stopped. Sometimes the hydraulic line is opened to release the braking. Since the optimal timing of brake release differs according to the road surface gradient when the vehicle is stopped, for example, in the technique of Patent Document 1, the brake release timing is set in consideration of the road surface gradient.

  However, as described in [Problems to be Solved by the Invention], when a trailer vehicle stops across two different road gradients θ, each road gradient θ needs to be considered, The road surface gradient θ on the tractor A side on which the acceleration sensor 33 is mounted is estimated as the road surface gradient θ of the entire trailer vehicle. As a result, there is a problem that based on the inappropriate road surface gradient θ, the starting stage cannot be accurately selected in the starting stage automatic selection control, and the braking release timing cannot be set appropriately in the slope starting assist control. In addition, it is conceivable to provide an acceleration sensor 33 on the trailer B side as a countermeasure. However, since various trailers B are connected to the tractor A, it is not possible to equip all trailers B with the acceleration sensor 33. Is possible.

  By the way, the trailer B always follows the traveling locus of the tractor A by towing the tractor A, so that the trailer B moves on the road surface on which the tractor A has traveled after a predetermined time (when it has moved by a movement determination value L0 described later). I will run. In view of this point, the present inventor does not specifically estimate the road surface gradient θ on the trailer B side, but accurately starts reflecting the road surface gradient θ of the entire trailer vehicle based on the road surface gradient θ on the tractor A side. It has been found that the selection of the stage and the precise setting of the brake release timing are possible. Based on such knowledge, in the present embodiment, the automatic selection control of the starting stage and the slope start assist control are executed based on the road surface gradient θ on the tractor A side, and the control will be described in detail below.

First, prior to the description of the actual control content, a control map for selecting the starting stage from the road surface gradient θ will be described.
FIG. 3 is an explanatory diagram showing a control map for selecting a starting stage. The horizontal axis is the road surface gradient θ, and based on a comparison between the road surface gradient θ and a preset judgment value, the third speed (flat road gear) is selected as the starting stage when the road surface gradient θ is small and the vehicle is gentle. As the road surface gradient θ increases and becomes steep, the starting speed is switched in order of the second speed (second slope shift speed) and the first speed (first slope shift speed). In addition, although not shown in figure, the 3rd speed is selected as a starting stage on the downhill road where road surface gradient (theta) becomes a negative value.

Different judgment values are applied on the shift-up side and the shift-down side so that hysteresis occurs in switching between the respective gears. Specifically, between the third speed and the second speed, a steep slope-side determination value θ32 (first determination value, first down-side determination value) and a gentle slope-side up-side determination value θ23. (First determination value, first up-side determination value) is set. Further, between the second speed and the first speed, a down-side determination value θ21 (second determination value) on the steep slope side and an up-side determination value θ12 (second determination value) on the gentle slope side are set. Has been.
For example, when the road surface gradient θ increases from 0 corresponding to a flat road and exceeds the down-side determination value θ32, the starting stage is switched from the third speed to the second speed, and the road surface gradient θ increases to determine the down side. When the value θ21 is exceeded, the starting stage is switched from the second speed to the first speed. Further, when the road surface gradient θ decreases and falls below the up-side determination value θ12, the start stage is switched from the first speed to the second speed, and when the road surface gradient θ decreases and falls below the up-side determination value θ23, the start stage changes. The second speed is switched to the third speed.

The control map of FIG. 3 is an example corresponding to a certain vehicle weight, and in fact, a large number of control maps having different characteristics for each vehicle weight are preset. Specifically, the determination values θ12, θ23, θ32, and θ21 are set on the gentle gradient side for the control map with a larger vehicle weight, and even if the road surface gradient θ is the same, the lower gear side gear stage is set. It is to be selected.
Then, a control map corresponding to the estimation result by the above-described vehicle weight estimation process is selected, and using the control map, any shift speed (hereinafter referred to as the selected shift speed is simply set as a start position from the road surface gradient θ). (Sometimes referred to as a starting stage) is selected. Thereby, the start stage reflecting the road surface gradient θ and the vehicle weight can be selected.

On the other hand, corresponding to the first speed and the second speed selected from the control map in this manner, the braking release timing applied in advance in the slope start assist control is set as a specified value. Further, in the case of the third speed, the brake release timing is calculated based on the road surface gradient θ and the vehicle weight as in the normal process without using the specified value.
For the third speed selected on a flat road or a road surface with a gentle slope close thereto (hereinafter referred to as the vicinity of a flat road), a relatively early braking release timing is calculated. Compared to this, at the first speed and the second speed selected on the uphill road, it is necessary to continue braking until the driving force overcomes the road surface gradient θ, so a later brake release timing is preset. Yes. Further, when comparing the brake release timings of the first speed and the second speed, a relatively early brake release timing is set for the second speed on the gentle slope side, and the first speed on the steep slope side is set. A relatively late braking release timing is set.

The ECU 21 executes the starting stage selection / cancellation timing setting routine shown in FIGS. 4 and 5 at a predetermined control interval when the ignition switch of the vehicle is turned on. Here, the ECU 21 has a start-stage storage function (storage means), and the shift stage currently selected as the start stage at the time of the previous ignition switch-off operation is stored in the storage device of the ECU 21. Shall.
When the ECU 21 starts the routine shown in FIG. 4, it is first determined in step S2 whether or not it is the first control interval after the ignition switch is turned on. When the determination is Yes (positive), the process proceeds to step S4, the shift speed is read from the storage device, and the shift speed is selected as the start speed at step S6. In the subsequent step S7, the brake release timing is set according to the selected gear position, and then the process proceeds to step S8. The process of step S7 has the same contents as steps S13, S19, and S29 described below, and the brake release timing is set differently depending on the selected gear position, the details of which will be described later. If the determination in step S2 is No (No), the process directly proceeds to step S8.

In step S8, a control map (for example, the map of FIG. 3) corresponding to the vehicle weight is selected based on the vehicle weight estimated by the vehicle weight estimation process. Based on the selected control map, the starting stage is selected and the brake release timing is set in the subsequent processing.
First, in step S10, it is determined whether or not the road surface gradient θ estimated by the road surface gradient estimation process is greater than or equal to the down-side determination value θ21. When the determination is Yes, the first speed is selected as the starting stage in step S12, the brake release timing corresponding to the first speed is set in the subsequent step S13 (brake release timing setting means), and then the routine is ended. When the determination in step S10 is No, it is determined in step S14 whether or not the road surface gradient θ is less than the up-side determination value θ12. If the determination is No, the process proceeds to step S12.

If the determination in step S14 is Yes, it is determined in step S16 whether or not the road surface gradient θ is equal to or greater than the down-side determination value θ32. If the determination is Yes, the process proceeds to step S18. In step S18, the second speed is selected as the starting stage, and in the subsequent step S19, the brake release timing corresponding to the second speed is set (brake release timing setting means), and then the routine is ended. If the determination in step S16 is No, it is determined in step S20 whether or not the road surface gradient θ is less than the up-side determination value θ23. If the determination is No, the process proceeds to step S18.
When the determination in step S20 is Yes, the process proceeds to step S22, and the moving distance L of the trailer vehicle is reset. In the following step S24, the movement distance L is updated according to the following equation (1).
L = L + V × DT (1)
Here, V is the vehicle speed of the trailer vehicle, and DT is the control interval of the starting stage selection / release timing setting routine. The vehicle speed V is treated as a positive value when the trailer vehicle moves forward, and is treated as a negative value when the trailer vehicle moves backward. For this reason, V × DT means the distance that the trailer vehicle has moved forward or backward during the control interval.

Further, the ECU 21 determines again in step S25 whether or not the road surface gradient θ is less than the up-side determination value θ23. When the determination is Yes, the process proceeds to step S26, and it is determined whether or not the movement distance L is equal to or greater than a predetermined movement determination value L0. When the determination is No, the routine is once terminated. Therefore, the movement distance L is updated in the increasing direction based on V × DT when the trailer vehicle moves forward, and updated in the decreasing direction based on V × DT when moving backward, at each control interval. As a result, the moving distance L is constantly updated to be the distance the trailer vehicle has moved from the time when the condition of step S20 is satisfied (when tractor A enters the flat road from the ascending road as described later) (measurement). means).
The movement determination value L0 is a determination value for determining whether or not the trailer B has entered the flat road following this after the tractor A has entered the flat road. There are various lengths of trailer B, and the longer the overall length of trailer B, the longer the travel distance L of the trailer vehicle required from the intrusion of tractor A to the flat road until the trailer B enters. The wheelbase of the trailer vehicle (the distance from the rear wheel Aa of the tractor A to the rear wheel of the trailer B as shown in FIG. 2) differs depending on the total length of the trailer B, and the wheel after the tractor A enters the flat road. It can be inferred that the trailer B side has also escaped from the uphill road and entered the flat road at the point where the trailer vehicle has traveled for the base equivalent.

Therefore, by setting the wheelbase of the trailer vehicle as the movement determination value L0 and applying it to the determination in step S18, switching of the starting stage from the first speed or the second speed to the third speed, which will be described later, at an appropriate timing. It can be executed.
However, since the trailer B connected to the tractor A changes according to the transportation request, there are many cases where the wheel base of the trailer vehicle cannot be specified. Therefore, in such a case, an appropriate value may be set in advance as the movement determination value L0 in consideration of safety and operability in accordance with the use or specification of the trailer vehicle.

On the other hand, if the determination of No is made in step S25 as described above, the routine is once terminated. This process is a countermeasure when the road gradient [theta] does not satisfy the condition below the up-side determination threshold [theta] 23 while the processes in steps S24 to S26 are repeated. In this case, the vehicle immediately starts at the next control interval. The second speed or the first speed is selected as the stage, and an appropriate brake release timing corresponding to the start stage is set.
If the determination of Yes continues in step S25 and the determination of step S26 becomes Yes, the ECU 21 proceeds to step S28 and selects the third speed as the starting stage. In the following step S29, the brake release timing is calculated based on the road surface gradient θ and the vehicle weight (brake release timing setting means), and then the routine is ended.

Next, the starting stage selection situation according to the road surface gradient θ by the above-described processing of the ECU 21 and the braking release timing setting situation will be described.
Now, when the ignition switch is turned on on a flat road, the trailer vehicle starts to travel after releasing the braking of the braking device 34, and then the trailer vehicle travels on the uphill road from the flat road and shifts to the flat road again. Will be explained. When the trailer vehicle is stopped on a flat road, it is possible to start smoothly at the third speed. When the trailer vehicle is stopped on an uphill road, a smooth start cannot be expected at the third speed, and the start stage is It is assumed that the second speed or the first speed needs to be selected.

First, when the ignition switch is turned on, the ECU 21 proceeds from step S2 in FIG. 4 to step S6 through step S4. Since the third speed corresponding to the flat road is stored in the storage device when the ignition switch was turned off last time, the third speed is read from the storage device and selected as the starting stage in steps S4 and S6. Further, since the third speed is selected, as in the case of the transition from step S28 to step S29, in step S7, an early braking release timing is calculated based on the road surface gradient θ near the flat road and the vehicle weight. .
Therefore, after that, the engine 1 is started and the trailer vehicle starts on a flat road, but the third speed is used as the starting stage, and braking of the braking device 34 is released at an early timing. For this reason, from the beginning when the ignition switch is turned on, the vehicle can be started smoothly and quickly with an appropriate start stage and an appropriate brake release timing.
When the first speed is stored as the starting stage, the same process as when the process proceeds from step S12 to step S13 in step S7 is executed. Further, when the second speed is stored, the same process as when the process proceeds from step S18 to step S19 in step S7 is executed. Therefore, even in these cases, an appropriate start stage and an appropriate brake release timing are applied.

The trailer vehicle after starting travels on a flat road as shown in FIG. 6, and a road surface gradient θ of almost zero is continuously estimated by the road surface gradient estimation process. The ECU 21 proceeds in the order of steps S10, 14, 16, and 20 in FIG. 5, and determines Yes in step S20, assuming that the road surface gradient θ is less than the up-side determination value θ23.
Then, the movement distance L is sequentially updated in the increasing direction by the processing of steps S22 to S26, and when the value L reaches the movement determination value L0, the process proceeds to step S28 and the third speed is selected as the starting stage. As a result, the third speed is continuously selected from the start of the vehicle, and the early braking release timing corresponding to the flat road is continuously set. Therefore, when the trailer vehicle stops on a flat road, the braking of the braking device 34 is released at the set earlier timing, and the third speed is started smoothly and quickly.

Next, as shown in FIG. 7, when the trailer vehicle reaches the uphill road, the trailer B side is still positioned on the flat road, but the tractor A side enters the uphill road and follows the uphill road. For this reason, the road surface gradient estimation process estimates a value equal to or greater than the down-side determination value θ32 as the road surface gradient θ. In particular, when the uphill road is steep, a value equal to or greater than the down-side determination value θ21 is estimated as the road surface gradient θ. .
When the road surface gradient θ is greater than or equal to the down-side determination value θ21, the ECU 21 proceeds from step S10 in FIG. 5 to step S12, selects the first speed as the starting stage, and sets the brake release timing corresponding to the first speed in step S13. Set. Further, when the road surface gradient θ is less than the up-side determination value θ12 but not less than the down-side determination value θ32, the process proceeds from step S16 to step S18 in FIG. 5 to select the second speed as the starting stage, and in step S19, the second speed is selected. Set the brake release timing corresponding to the speed.

In the trailer vehicle at this time, the tractor A side is affected by the road surface gradient θ of the uphill road as shown in FIG. Therefore, if the trailer vehicle stops in this state, smooth start of the vehicle cannot be expected at the third speed, but since the first speed or the second speed corresponding to the road surface gradient θ is selected, the start is performed smoothly and quickly. Is called.
In addition, it is necessary to delay the brake release timing on an uphill road compared to a flat road in order to prevent rearward slipping of the vehicle. In particular, on a steep uphill road where the first speed is selected, it is desirable to further delay the brake release timing than in the case of the second speed. As is clear from the above description, the first speed and the second speed are selected reflecting the vehicle weight and the road surface gradient θ of the uphill road, and the brake release timing is set corresponding to these shift stages. . As a result, the braking of the braking device 34 can be released at an appropriate timing according to the road surface gradient θ of the uphill road.

As shown in FIG. 8, when the trailer vehicle further travels, the trailer B side also follows the uphill road, and in the road surface gradient estimation process, it is still a value equal to or greater than the down-side determination value θ32 or a value equal to or greater than the down-side determination value θ21. Continue to be estimated.
Therefore, the ECU 21 continues to select the first speed in step S12 or the second speed in step S18, and continues to set the brake release timing corresponding to the gear position in steps S13 and S19. Both the tractor A side and the trailer B side are affected by the road slope θ of the uphill road, but when starting after the vehicle stops, the braking of the braking device 34 is released at an appropriate timing and smoothed by the first speed or the second speed. And a quick start is performed.

Further, the road surface gradient θ estimated at this time only slightly exceeds the down-side determination value θ21, and the gradient θ of the uphill road is not uniform and may vary as the vehicle travels. In such a case, the road surface gradient θ estimated during traveling on the uphill road may temporarily decrease and slightly lower than the down-side determination value θ21. The ECU 21 makes a determination of No in step S10, but continues to select the first speed in step S12 in order to make a determination of No assuming that the road surface gradient θ is greater than or equal to the up-side determination value θ12 in step S14. Continue setting the brake release timing.
When the process of step S14 is not performed, the road surface gradient θ increases or decreases in the vicinity of the down-side determination value θ21, whereby the first speed and the second speed are alternately selected, and the brake release timing also varies accordingly. For this reason, the start stage and the brake release timing selected when the vehicle stops may not necessarily be appropriate. By providing the process of step S14, it is possible to set an appropriate start stage and braking release timing even in such a road surface condition.
The same applies to the down-side determination value θ32 in step S16. By providing the processing in step S20 regarding the up-side determination value θ23, the second speed and the third speed are alternately selected by the gradient fluctuation of the uphill road. And a situation in which the brake release timing fluctuates accordingly can be prevented.

On the other hand, as shown in FIG. 9, when the trailer vehicle further travels and reaches the flat road, the trailer B side is still located on the uphill road, but the tractor A side is removed from the uphill road and follows the flat road. Become posture.
Therefore, a road surface gradient θ of approximately zero is estimated as the road surface gradient θ by the road surface gradient estimation process. The ECU 21 makes a Yes determination in step S20 of FIG. 5, but determines that the movement distance L has not reached the movement determination value L0 and makes a No determination in step S26. Therefore, the ECU 21 does not immediately proceed to step S28. Therefore, without selecting the third speed as the starting stage, the first speed or the second speed is continuously selected, and the corresponding brake release timing is continuously set.
In the trailer vehicle at this time, as shown in FIG. 9, the trailer B side is still affected by the road surface gradient θ of the uphill road. If the trailer vehicle stops in this state, smooth start of the vehicle cannot be expected at the third speed, and the braking release timing calculated from the road surface gradient θ of almost 0 is too early, causing a backlash when the vehicle starts. However, at this time, the first speed or the second speed corresponding to the road surface gradient θ is selected, and the braking of the braking device 34 is released at a later timing corresponding to the road surface gradient θ of the uphill road.

On the other hand, when the tractor A side enters the flat road in this way, the ECU 21 starts updating the movement distance L in step S24 of FIG. The moving distance L can be regarded as the distance that the trailer vehicle has moved since the tractor A side entered the flat road, and when the moving distance L reaches the movement determination value L0, it follows the tractor A as shown in FIG. Thus, the trailer B side also takes the posture following the uphill road and following the flat road. The ECU 21 proceeds from step S26 in FIG. 5 to step S28, selects the third speed as the starting stage, and calculates braking release timing based on the road surface gradient θ and the vehicle weight in the subsequent step S29.
At this point, the entire trailer vehicle has already shifted to a flat road, so even if the trailer vehicle stops, there is no need to select the first speed or the second speed as the starting stage, and the third speed will start smoothly and quickly. Is done.
Further, neither the tractor A side nor the trailer B side is affected by the road surface gradient θ, and the road surface gradient θ on the trailer B side is substantially equal to the road surface gradient θ on the tractor A side estimated by the road surface gradient estimation process. Can be considered. Therefore, the braking release timing calculated based on the road surface gradient θ on the tractor A side and the vehicle weight estimated at this time is the optimum for releasing the braking device 34 of the current trailer vehicle stopped on a flat road. Can be considered a value. Therefore, the braking of the braking device 34 can be released at an optimal timing by this braking release timing.

As described above, during the period from when the tractor A side enters the uphill road until the tractor A side leaves the uphill road and travels by the movement determination value L0, at least one of the tractor A side or the trailer B side is on the uphill road. It is influenced by the road surface gradient θ. For this reason, the first gear or the second gear, which is the low gear side slope shift gear, is selected as the starting gear, and the slow braking release corresponding to the first gear and the second gear is performed as the braking release timing of the braking device 34. Each timing is set. Further, before and after the above period, neither the tractor A side nor the trailer B side is affected by the road surface gradient θ. For this reason, the third speed, which is a high-speed flat road shift stage, is selected as the starting stage, and early braking release timing is calculated based on the estimated road surface gradient θ and the vehicle weight.
As a result, without providing a detecting means such as the acceleration sensor 33 on the trailer B side, the braking holding accompanying the stopping on the uphill road is performed at an appropriate timing based on the road surface gradient θ estimated by the acceleration sensor 33 provided on the tractor A side. The vehicle can be started smoothly and quickly at the optimum start stage.

In addition, as described with reference to FIGS. 4 and 5, in the present embodiment, the determination of the road surface gradient θ (steps S10, 14, 16, 20) and the determination of the movement distance L (steps S22 to S26) are basically performed at control intervals. Since it is a relatively simple process that only needs to be executed every time, the ECU 21 is not required to have a very high computing capacity or memory capacity. Therefore, the effect that it can implement at low cost, without requiring the specification change of ECU21 itself, etc. is also acquired.
In step S24, the moving distance L is updated in the subtraction direction when the vehicle is moving backward. For this reason, even when the tractor A temporarily moves backward after entering the flat road, it is possible to calculate an appropriate movement distance L, and more appropriately select the first speed, the second speed and the third speed, The braking can be released at an appropriate timing corresponding to these shift speeds.

  Also, in steps S10, 14, 16, and 20, either the first speed or the second speed is selected as the starting speed according to the slope θ of the uphill road, and the braking corresponding to the selected shifting speed. Each release timing is set. As a result, the starting stage can be selected more finely in accordance with the road surface gradient θ as compared with the case where a single slope shift stage is used. Therefore, the brake release timing can be set finely corresponding to each start stage, and the brake can be released at a more appropriate timing.

  In the above embodiment, the braking release timing is calculated based on the road gradient θ and the vehicle weight when the third speed is selected as the starting stage, but the present invention is not limited to this. For example, as in the case of selecting the first speed or the second speed, the brake release timing corresponding to the gear position may be calculated for the third speed. FIG. 11 is a flowchart showing the processing of the ECU 21 as another example, and the processing will be described below. It should be noted that the processing of parts not shown in the figure is the same as in FIGS.

  In order to calculate the brake release timing corresponding to the third speed, the brake release timing applied in advance in the slope start assist control is set as the specified value for the third speed as well as the first speed and the second speed. Is set. Needless to say, the braking release timing of the third speed is earlier than the braking release timing of the first speed and the second speed, more specifically, the vehicle starts on a flat road (or an approximate gentle slope). It is set as a timing at which braking by the braking device 34 can be properly released when the braking is performed.

In FIG. 11, when the ECU 21 determines Yes in step S26 based on the travel distance L of the trailer vehicle, it selects the third speed as the start stage in step S28. In the subsequent step S31, the brake release timing corresponding to the third speed is set (brake release timing setting means), and then the routine is ended.
With the above processing, when the third speed is selected as the starting stage, the brake release timing earlier than the first speed and the second speed corresponding to the flat road is applied. Therefore, also in the third speed, the braking holding can be released at an appropriate timing, and although not redundantly described, the same operational effects as in the above embodiment can be obtained.

This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, the trailer vehicle of the above embodiment includes the automatic transmission 3 based on the manual transmission, but is not limited thereto, and may include a manual transmission, or a planetary planet that includes a torque converter. A gear-type automatic transmission or a CVT-type automatic transmission may be provided.
Moreover, in the said embodiment, although the movement distance L was computed from the vehicle speed V and the control interval of ECU21 based on Formula (1), it does not restrict to this. For example, the moving distance L may be calculated from the odometer value using an existing odometer that counts the accumulated distance of the trailer vehicle.

In the above embodiment, the down-side determination values θ32 and θ21 and the up-side determination values θ23 and 12 are applied as the determination values in order to deal with the gradient fluctuation of the uphill road and the downhill road. However, the present invention is not limited to this. One determination value may be applied. Specifically, steps S14 and S20 in FIG. 5 are omitted, and only the determination based on the down-side determination value θ21 in step S10 and the determination based on the down-side determination value θ32 in step S16 may be executed.
In the above embodiment, the starting stage automatic selection control and the slope starting assistance control are executed assuming an uphill road, but the same control may be executed on a downhill road in addition to this. On downhill roads, the trailer vehicle can be started with a smaller driving force than on flat roads. For example, a higher gear shift stage is selected as the start stage and an earlier brake release timing is set. Good.

21 ECU
(Start stage selection means, road surface gradient estimation means, vehicle weight estimation means, slope start assistance means,
(Braking release timing setting means, storage means, measurement means)
33 Acceleration sensor (detection means)
A Tractor B Trailer

Claims (6)

In a trailer vehicle in which a tractor on a towing side equipped with a power source for traveling and a trailer on a towed side loaded with a load are connected so that the angle can be arbitrarily changed,
Road surface gradient estimation means for estimating the gradient of the road surface on which the tractor is located based on detection information of the detection means provided on the tractor side;
A vehicle weight estimation unit Ru estimated Teisu the weight of the trailer vehicle,
Measuring means for measuring the travel distance of the trailer vehicle during travel of the trailer vehicle;
When the trailer vehicle travels, when the estimated road surface gradient by the road surface gradient estimation unit becomes equal to or greater than a first determination value set as a threshold based on the vehicle weight by the vehicle weight estimation unit , After selecting the slope shift speed, the estimated road surface gradient subsequently decreases to less than the first determination value, and then the movement distance of the trailer vehicle reaches a predetermined movement determination value based on the measurement of the measuring means. Starting stage selecting means for selecting a high gear side flat road shift stage as the starting stage,
A slope start assisting means for operating the braking device when the trailer vehicle is stopped to hold the trailer vehicle in a braking state, and releasing the braking of the braking device at the subsequent start;
Based on the start stage selected by the start stage selecting means, the braking release timing by the slope start assisting means is calculated, and when the slope shift stage is selected as the start stage, the flat road shift stage is selected. Braking release timing setting means for delaying the brake release timing as compared to when the vehicle is traveling, the movement determination value is set as a wheel base of the trailer vehicle, and the start stage selection means is based on the movement determination value. A trail start assisting device for a trailer vehicle , wherein the selection of the flat road shift stage is determined, and the brake release timing setting means sets the brake release timing based on the start stage selected by the start stage selecting means . In a trailer vehicle in which a tractor on a towing side equipped with a power source for traveling and a trailer on a towed side loaded with a load are connected so that the angle can be arbitrarily changed,
Road surface gradient estimation means for estimating the gradient of the road surface on which the tractor is located based on detection information of the detection means provided on the tractor side;
Vehicle weight estimation means for estimating the weight of the trailer vehicle;
Measuring means for measuring the travel distance of the trailer vehicle during travel of the trailer vehicle;
When the trailer vehicle travels, when the estimated road surface gradient by the road surface gradient estimation unit becomes equal to or greater than a first determination value set as a threshold based on the vehicle weight by the vehicle weight estimation unit, After selecting the slope shift speed, the estimated road surface gradient subsequently decreases to less than the first determination value, and then the movement distance of the trailer vehicle reaches a predetermined movement determination value based on the measurement of the measuring means. Starting stage selecting means for selecting a high gear side flat road shift stage as the starting stage,
A slope start assisting means for operating the braking device when the trailer vehicle is stopped to hold the trailer vehicle in a braking state, and releasing the braking of the braking device at the subsequent start;
Based on the start stage selected by the start stage selecting means, the braking release timing by the slope start assisting means is calculated, and when the slope shift stage is selected as the start stage, the flat road shift stage is selected. Braking release timing setting means for delaying the brake release timing as compared to when the trailer vehicle is moving, and the measuring means sets the reverse distance when the trailer vehicle moves backward during measurement of the movement distance of the trailer vehicle. Subtracting from the moving distance, the starting stage selecting means determines the selection of the flat road speed stage based on the moving distance after subtraction, and the braking release timing setting means based on the starting stage selected by the starting stage selecting means Sets the brake release timing, the trail start assist device for trailer vehicles. The braking release timing setting means sets the braking release timing to an earlier timing set in advance corresponding to the flat road speed when the starting speed selection means selects the flat road speed, and selects the slope speed 3. A trail start assist device for a trailer vehicle according to claim 1 or 2 , wherein the braking release timing is set to a later timing set in advance corresponding to a slope shift stage. The above-mentioned slope shift stage is switched with a second judgment value set in advance as a steeper value than the first judgment value as a boundary, and the first slope stage on the low gear side and the second on the high gear side. It consists of a slope shift stage,
The start stage selection means selects the first slope shift stage as the start stage when the estimated road surface gradient is greater than or equal to the second determination value, and the start stage when the estimated road surface gradient is less than the second determination value. When the second slope shift stage is selected as the stage, and then the estimated road surface gradient is reduced to less than the first determination value and then it is determined that the movement distance has reached the movement determination value, a flat road is used as the start stage. Select the gear position,
The brake release timing setting means sets the brake release timing to an earlier timing set in advance corresponding to the second slope shift stage when the second stage shift stage is selected by the start stage selection means, and the first slope road 4. The trail start assist device for a trailer vehicle according to claim 3 , wherein, when selecting a shift speed, the brake release timing is set to a later timing set in advance corresponding to the first slope shift speed. The first determination value includes a first down side determination value set in advance as a steep slope side value and a first up side determination value set as a gentle slope side value,
The start stage selecting means selects the slope shift stage based on the first down-side determination value, and selects the flat road shift stage based on the first up-side determination value. The trail start assist device for a trailer vehicle according to any one of 1 to 4 . When the ignition switch of the trailer vehicle is turned off, storage means for storing a shift stage selected as a start stage by the start stage selection means at that time,
6. The trail start of a trailer vehicle according to any one of claims 1 to 5 , wherein the start stage selecting means selects the shift stage stored in the storage means as a start stage when the ignition switch is turned on. Auxiliary device.

Images