JP6057783B2 - Trailer vehicle slope start assist device - Google Patents

Description

  The present invention relates to a trail start vehicle slope assisting device, and more specifically, the brake device is operated when temporarily stopping on an uphill road to hold the vehicle in a braking state, and the brake device is braked at an appropriate timing at the subsequent start. It is related with the slope start assistance apparatus of the trailer vehicle which cancels | releases and can start a vehicle.

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. 8, 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. 8, when the vehicle is stopped with the tractor A side positioned on a flat road, a gentle road surface gradient (approximately 0) is estimated from the detection information of the acceleration sensor. 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 trailer vehicle start assist device that can always release braking at an appropriate timing based on a slope.

  In order to achieve the above object, the present invention provides 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 on which a load is loaded are connected so that the angle can be arbitrarily changed. A road surface gradient estimating means for estimating the gradient of the road surface on which the tractor is located based on detection information of the detecting means provided on the tractor side, a measuring means for measuring the travel distance of the trailer vehicle during travel of the trailer vehicle, and a trailer Starting stage selecting means for selecting a starting stage when starting the vehicle, vehicle weight estimating means for estimating the weight of the trailer vehicle, and operating the braking device when the trailer vehicle stops to hold the trailer vehicle in a braking state; The slope start assisting means for releasing the braking of the braking device at the time of the subsequent start, and the estimated road surface gradient by the road surface slope estimating means during the traveling of the trailer vehicle are preset. When the value is equal to or greater than the road determination value, the braking release timing of the slope start assisting means is set corresponding to the starting stage selected by the starting stage selecting means based on a preset map, and then the estimated road surface gradient is When the travel distance of the trailer vehicle reaches a preset movement judgment value based on the measurement by the measuring means after decreasing to less than the slope judgment value, the estimated road surface gradient by the road surface slope estimation means and the estimated vehicle by the vehicle weight estimation means And a brake release timing setting means for setting a brake release timing of the slope start assisting means based on the weight.

  During the period from the time when the tractor side enters the uphill road to the time when the vehicle exits the uphill road and travels by the movement judgment value, at least one of the tractor side or the trailer side is located on the uphill road and is affected by the road slope Therefore, the road surface gradient estimated on the tractor side is not always appropriate. On the other hand, when the trailer vehicle stops, the start stage is selected by the driver for the subsequent start. Since the starting stage at this time is selected in consideration of the vehicle weight and the road surface gradient, the braking of the braking device can be appropriately released based on the braking releasing timing corresponding to the starting stage.

  Further, the road surface gradient estimated on the tractor side can be regarded as appropriate before and after the above period. For this reason, the braking of the braking device can be appropriately released based on the braking release timing set from the estimated road surface gradient and the estimated vehicle weight. As a result, it is possible to always release the brake at an appropriate timing based on the road surface gradient estimated by the detecting means provided on the tractor side without providing a detecting means such as an acceleration sensor on the trailer side.

As another aspect, the movement determination value may be set as the wheel base of the trailer vehicle, and the brake release timing setting means may determine the movement distance of the trailer vehicle based on the movement determination value.
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 method for setting the brake release timing can be switched more accurately.

As another aspect, when the trailer vehicle moves backward during measurement of the movement distance of the trailer vehicle, the measuring means subtracts the backward distance from the movement distance, and the brake release timing setting means is based on the movement distance after the subtraction. The movement distance may be determined.
Even when the tractor is temporarily retracted after leaving the uphill road, an appropriate movement distance can be calculated, so that the method for setting the brake release timing can be switched more accurately.

As another aspect, the start stage selection means may select the start stage according to the operation of the driver. Even when the driver selects the starting stage, braking can be released at an appropriate timing.
As another aspect, the start stage selection means may select the start stage based on the estimated road surface gradient and the estimated vehicle weight. Even when the starting stage is automatically selected from the estimated road surface gradient and the estimated vehicle weight, the braking can be released at an appropriate timing.

  According to the present invention, it is possible to always release the brake at an appropriate timing based on the road surface gradient estimated by the detecting means provided on the tractor side without providing a detecting means such as an acceleration sensor on the trailer side.

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 map for switching the setting mode of braking cancellation | release timing. It is a flowchart which shows the brake 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.

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. doing.

  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.

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. Compressed air from the air tank 11 is supplied to the corresponding air cylinder according to the opening and closing of each solenoid valve, and when the corresponding air cylinder is operated to switch the corresponding shift fork, the gear stage of the transmission 3 is switched according to the switching operation. Is switched.

  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. , An acceleration sensor 33 (detection means) mounted on the tractor A for detecting the longitudinal acceleration Gs, and an uphill road Sensors such as a start stage selection switch 35 for the driver to select a start stage when the vehicle stops are connected.
In the present embodiment, the first to third speeds of the transmission 3 are set in advance as start stages, and any of these shift stages is selected by the start stage selection switch 35 (start stage selecting means).

  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.

  For example, the ECU 21 calculates the 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. The fuel injection timing is calculated from a map (not shown) based on the engine 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 and a vehicle weight estimation process for estimating the weight of the trailer vehicle as will be described later. The weight is used as a slope start assist device.
The road surface gradient θ estimation processing is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-097945. Therefore, only a brief description will be given. For example, the longitudinal acceleration Gv actually generated in the vehicle is obtained from the vehicle speed V detected by the vehicle speed sensor 28, and the longitudinal acceleration Gv and the longitudinal acceleration Gs detected by the acceleration sensor 33 are obtained. Based on this, the road surface gradient θ is estimated (road surface gradient estimating means).

Further, the vehicle weight estimation process is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-340165, and the vehicle weight (the weight of the tractor A + the trailer B) is estimated from the vehicle driving torque and the vehicle acceleration, for example (vehicle weight). Estimation means).
The slope start assist device operates the braking device 34 when the vehicle is temporarily stopped on the uphill road to hold the vehicle in a braking state, and stops the braking device 34 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, the slope start assist device keeps the hydraulic pressure increased by the brake operation even after the driver's brake operation is stopped by cutting off the hydraulic line of the braking device 34 when the trailer vehicle is temporarily stopped. The brake is continued, and the hydraulic line is opened to release the brake when starting thereafter. 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 in that the braking release timing cannot be set appropriately in the slope start assist control based on the inappropriate road surface gradient θ.
Here, the present inventor has paid attention to the fact that such an inappropriate estimation of the road surface gradient θ occurs only during a certain period when traveling on an uphill road.
That is, when the trailer vehicle is traveling, the trailer B always follows the tractor A by traction of the tractor A. At the time of traveling on the uphill road, at least one of the tractor A side or the trailer B side is on the uphill road during the period from the time when the tractor A side enters the uphill road to the time when the tractor A leaves the uphill road and travels by the movement determination value L0. Positioned and affected by road surface gradient θ. For this reason, the road surface gradient θ estimated on the tractor A side is inappropriate only during this period.

On the other hand, when the trailer vehicle starts, the driver selects a start stage using the start stage selection switch 35, and the start stage is started. Since the starting stage at this time is selected in consideration of the road surface gradient θ and the vehicle weight, it can be used as an index for setting the brake release timing instead of the inappropriate estimated road surface gradient θ. As a result, the braking release timing can be appropriately set based on the road surface gradient θ on the tractor A side without specifically estimating the road surface gradient θ on the trailer B side.
Based on such knowledge, in the present embodiment, it is determined whether or not the road surface gradient θ is in an inappropriate period, and the setting mode of the brake release timing is switched accordingly. Detailed description.

First, before explaining the actual control contents, a map for switching the setting mode of the brake release timing from the road surface gradient θ will be described.
FIG. 3 is an explanatory diagram showing a map for switching the setting mode of the brake release timing. The horizontal axis is the road surface gradient θ. Based on a comparison between the road surface gradient θ and a preset judgment value, the third setting mode is selected when the road surface gradient θ is small and the vehicle is gentle, and the road surface gradient θ increases and suddenly increases. As the gradient is reached, the second setting mode and the first setting mode are switched in this order. Although not shown, the third setting mode is selected on a downhill road where the road surface gradient θ is 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 setting modes. Specifically, between the third setting mode and the second setting mode, a steep slope-side determination value θ32 (gradient determination value) and a gentle gradient-side determination value θ23 (gradient determination value) are set. ing. In addition, between the second setting mode and the first setting mode second speed, a steep slope-side down determination value θ21 and a gentle slope-side up determination value θ12 are set.

  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 mode is switched from the third setting mode to the second setting mode, and the road surface gradient θ increases and the down-side determination value is increased. When θ21 is exceeded, the second setting mode is switched to the first setting mode. Further, when the road surface gradient θ decreases and falls below the up-side determination value θ12, the first setting mode is switched to the second setting mode, and when the road surface gradient θ decreases and falls below the up-side determination value θ23, the second setting mode. To the third setting mode.

Next, the setting contents of the brake release timing in each setting mode will be described.
In the third setting mode, the brake release timing is set using the road surface gradient θ and the vehicle weight as indices. Since the details are the same as the conventional method, the details will not be explained. However, the greater the road gradient θ or the greater the vehicle weight, the more likely the backlash will occur at the start of the vehicle. The release timing is set to the delay side.

  In the first and second setting modes, the brake release timing is set using the start stage selected by the start stage selection switch 35 as an index. Therefore, maps for setting the brake release timing corresponding to the respective starting speeds (first to third speeds) are set for each of the first and second setting modes. In any setting mode map, the brake release timing is set to the delay side as the gear position on the low gear side (first speed side) is changed. Further, when the first setting mode and the second setting mode are compared, the braking release timing on the delay side is set in the first setting mode as compared with the second setting mode in any starting stage.

The ECU 21 executes a brake release timing setting routine shown in FIG. 4 at a predetermined control interval when the ignition switch of the vehicle is turned on.
When the ECU 21 starts the routine of FIG. 4, first, in step S4, the ECU 21 determines whether or not the road surface gradient θ estimated by the road surface gradient estimation process based on the map of FIG. 3 is equal to or greater than the down-side determination value θ21. When the determination is Yes, the first setting mode is selected in step S6, and the brake release timing is set in accordance with the start stage selected by the start stage selection switch 35 based on the first setting mode (braking release timing setting means). ) And then the routine ends. If the determination in step S4 is No, it is determined in step S8 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 S6.

  When the determination in step S8 is Yes, it is determined in step S10 whether the road surface gradient θ is equal to or greater than the down-side determination value θ32, and when the determination is Yes, the process proceeds to step S12. In step S12, the second setting mode is selected, the braking release timing is set corresponding to the start stage based on the second setting mode (braking release timing setting means), and then the routine is ended. When the determination in step S12 is No, it is determined in step S14 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 S12.

If the determination in step S14 is Yes, the process proceeds to step S16, and the moving distance L of the trailer vehicle is reset. In the following step S18, 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 brake 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.

In step S20, the ECU 21 again determines 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 S22, where 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 process returns to step S18.
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 S14 is satisfied (when tractor A enters the flat road from the uphill 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 wheel base of the trailer vehicle as the movement determination value L0 and applying it to the determination in step S22, 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, it is often impossible to specify the wheel base of the trailer vehicle. Therefore, in this 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 and specifications of the trailer vehicle.

Thus, when the determination in step S22 is Yes, the ECU 21 proceeds to step S24, selects the third setting mode, and sets the brake release timing based on the road surface gradient θ and the vehicle weight based on the third setting mode ( Brake releasing timing setting means), and then the routine is terminated.
On the other hand, once the determination of No is made in step S20 as described above, the routine is finished once. This process is a countermeasure when the road surface gradient θ does not satisfy the condition less than the up-side determination threshold value θ23 while the processes in steps S18 to S22 are repeated. In this case, at the next control interval, the mode is immediately switched to the first setting mode or the second setting mode, and an appropriate braking release timing is set based on the setting mode.

Next, the setting state of the brake release timing by the above-described processing of the ECU 21 will be described.
It is assumed that the trailer vehicle that is currently traveling travels on an uphill road from a flat road and shifts to a flat road again. 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. In addition, when the vehicle stops at any point, the selection switch 35 is switched by the driver so that the start stage is appropriate for the road surface gradient θ at that point.

As shown in FIG. 5, when the trailer vehicle is traveling on a flat road, the road surface gradient estimation process continues to estimate a substantially zero road surface gradient θ, that is, an appropriate road surface gradient θ corresponding to the flat road.
Then, as shown in FIG. 6, when the trailer vehicle reaches the uphill road, the tractor A side enters the uphill road and follows the uphill road, and the road surface gradient θ is a value greater than the down-side determination value θ32, particularly a steep road. For the gradient, a value equal to or greater than the down-side determination value θ21 is estimated. However, since the trailer B side is still located on a flat road, the road surface gradient θ at this time can be regarded as inappropriate.

As shown in FIG. 7, when the trailer vehicle further travels, the trailer B side also assumes a posture following the uphill road, and an appropriate road gradient θ corresponding to the uphill road is temporarily estimated. However, as shown in FIG. 8, when the trailer vehicle enters the flat road, a road surface gradient θ of approximately 0 is estimated. However, since the trailer B side is still located on the uphill road, the road surface gradient θ at this time is appropriate. Is not.
Then, as shown in FIG. 9, when the trailer vehicle has traveled by the movement determination value L0, the trailer B side also takes the posture that follows the flat road and follows the flat road. Is an appropriate value.

Accordingly, during the period from when the tractor A side shown in FIG. 6 enters the uphill road to the time when 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 Since it is located on the uphill road and is affected by the road surface gradient θ, the road surface gradient θ estimated on the tractor A side is not necessarily appropriate.
During this period, the ECU 21 continues to select the first setting mode in step S6 or the second setting mode in step S12 in FIG. On the other hand, when the trailer vehicle stops, the start stage is selected by the driver for the subsequent start, and the start stage at this time is selected in consideration of the vehicle weight and the road surface gradient θ as described above. Based on such a starting stage, the braking release timing is set in the first setting mode or the second setting mode, so that the braking of the braking device 34 can be released appropriately.

On the other hand, the road surface gradient θ estimated on the tractor A side can be regarded as appropriate before and after the above period (before entering the uphill road on the tractor A side and after traveling on the movement determination value L0). During this period, the ECU 21 selects the third setting mode in step S24 in FIG. 4 and sets the brake release timing based on the road surface gradient θ and the vehicle weight, so that the braking of the braking device 34 can be released appropriately. it can.
As a result, according to the trail start assist device for a trailer vehicle of the present embodiment, the estimated road surface gradient θ and the driver by the acceleration sensor 33 provided on the tractor A side without providing a detection means such as an acceleration sensor on the trailer B side. By appropriately using the starting stage selected by the vehicle as an index, it is possible to always set an appropriate braking release timing, so that it is possible to release braking holding accompanying stopping on an uphill road at an appropriate timing.

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, in the above embodiment, the driver selects the starting stage by the starting stage selection switch 35, but the present invention is not limited to this. For example, in a vehicle provided with a hold range that can maintain an arbitrary shift stage apart from the automatic shift mode of the D range, the start stage may be selected using the hold range.
Specifically, for example, the second speed is selected as the starting stage when the trailer vehicle stops, and when the driver determines that the second speed is inappropriate, the change lever 13 is moved from the hold range to the + range or -It may be possible to change to the third speed or the first speed by tilting to the range.

Further, instead of manually selecting the start stage by the driver, the start stage may be automatically selected by the processing of the ECU 21. Since the automatic selection control of the starting stage is well known, the details are not described. First, the current vehicle weight (the weight of the tractor A + the trailer B) is estimated by the vehicle weight estimation process, and based on the vehicle weight and the road surface gradient θ. A start stage may be selected (start stage selection means).
On the other hand, in the above embodiment, the down-side determination values θ32, θ21 and the up-side determination values θ23, 12 are applied as determination values so that hysteresis occurs in switching between the setting modes. However, the present invention is not limited to this. One determination value may be applied.

1 Engine (Power source for running)
21 ECU
(Road slope estimation means, measurement means, vehicle weight estimation means, slope start assist means,
(Braking release timing setting means, starting stage selection means)
33 Acceleration sensor (detection means)
34 Braking device 35 Start stage selection switch (start stage selection means)
A Tractor B Trailer

Claims (5)

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;
Measuring means for measuring the travel distance of the trailer vehicle during travel of the trailer vehicle;
Start stage selection means for selecting a start stage when starting the trailer vehicle;
Vehicle weight estimation means for estimating the weight of the trailer vehicle;
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;
The starting stage selected by the starting stage selecting means based on a preset map when the estimated road slope by the road slope estimating means becomes greater than or equal to a preset slope judgment value during travel of the trailer vehicle. The braking start timing of the slope start assisting means is set correspondingly, and then the travel distance of the trailer vehicle is set in advance based on the measurement of the measuring means after the estimated road surface slope is lowered to less than the slope judgment value. Braking release timing setting means for setting the braking release timing of the slope start assisting means based on the estimated road surface gradient by the road surface gradient estimating means and the estimated vehicle weight by the vehicle weight estimating means when the determined movement determination value is reached. A trail start assisting device for a trailer vehicle.   2. The trailer vehicle according to claim 1, wherein the movement determination value is set as a wheel base of the trailer vehicle, and the braking release timing setting means determines a movement distance of the trailer vehicle based on the movement determination value. Hill starting assistance device.   The measuring means subtracts the reverse distance from the movement distance when the trailer vehicle moves backward during measurement of the movement distance of the trailer vehicle, and the brake release timing setting means is based on the movement distance after subtraction. 3. The trail start assist device for a trailer vehicle according to claim 1, wherein the travel distance of the trailer vehicle is determined.   4. The trail start assist device for a trailer vehicle according to claim 1, wherein the start stage selecting means selects the start stage in accordance with a driver's operation.   The trail start vehicle slope assisting apparatus according to any one of claims 1 to 3, wherein the start stage selection means selects the start stage based on the estimated road surface gradient and the estimated vehicle weight.

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