JP6057053B2 - Trailer vehicle road slope estimation device - Google Patents

Description

  The present invention relates to a road surface gradient estimation device for a trailer vehicle, and more particularly to a road surface gradient estimation device that can individually estimate road surface gradients on a tractor side and a trailer side.

The road surface gradient estimated by this type of road surface gradient estimation device is used for various vehicle controls, and is used, for example, for determining the brake release timing of a slope start assist device. As is well known, the slope start assist device automatically activates and stops the braking device on the uphill road to eliminate the troublesome brake operation when starting the vehicle. Specifically, when the vehicle is temporarily stopped on an uphill road, the braking device is operated to hold the vehicle in a braking state, and then the braking device is stopped when the vehicle is started by depressing the accelerator to release the braking state. (For example, refer to 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 change in air pressure of the air suspension. With regard to the road surface gradient, in view of the fact that it is easy for rearward slipping of the vehicle to occur in a steep gradient, the braking state is maintained until the driving force sufficiently increases by delaying the timing of brake release as the road surface gradient is steep. I am doing so.

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 FIGS. In general vehicles, these two types of road surface gradients are parked in an averaged posture, so it is possible to determine the appropriate braking release timing based on the road surface gradient estimated from the detection information of the acceleration sensor mounted on the vehicle, for example. No problem arises.
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, so that the vehicle straddles two different road surface gradients. When the vehicle stops, the tractor A side and the trailer B side take different postures in the pitching direction, and the road surface gradients differ 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, for example, the above-mentioned slope start assist device causes a problem that braking is released at an incorrect timing due to an inappropriate estimation of the road surface gradient.
More specifically, as shown in FIG. 7, when the vehicle stops in a posture in which the tractor A side is positioned at a steep slope, a steep road surface gradient is estimated from the detection information of the acceleration sensor, but the road surface gradient received by the entire vehicle is Since it is not so steep, the brake release timing is too late. Conversely, as shown in FIG. 8, when the vehicle is stopped in a posture where the tractor A side is positioned on a horizontal road, a gentle road surface gradient (approximately 0) is estimated from the detection information of the acceleration sensor, but the road surface 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. Further, if an acceleration sensor is also provided on the trailer B side as a countermeasure, another problem of an increase in manufacturing cost occurs.
The present invention has been made to solve such problems, and the object of the present invention is to provide a tractor side and a trailer side even when the vehicle stops over two different road gradients. An object of the present invention is to provide a trailer vehicle road surface gradient estimation device capable of appropriately estimating a road surface gradient.

In order to achieve the above object, a first aspect of the present invention provides a road surface gradient estimation device for a trailer vehicle that can individually estimate the gradient of the road surface on which the tractor is located and the gradient of the road surface on which the trailer is located. A road surface gradient estimating means provided for estimating the road surface gradient, and a storage means for storing the road surface gradient sequentially estimated by the road surface gradient estimating means during traveling of the trailer vehicle together with position information based on the position of the current tractor. When the trailer vehicle stops, the latest road surface gradient estimated by the road surface gradient estimation unit is determined as the gradient of the road surface on which the tractor is located, and the current tractor is determined based on each position information stored in the storage unit. The road gradient corresponding to the trailer position is selected based on the position, and the selected road gradient is determined as the road gradient where the trailer is located. That a road gradient determining means, road surface gradient estimating means estimates the road surface gradient to a preset sampling per period, storage means, based on the moving distance of the tractor during the sampling period, the road surface gradient is estimated The travel distance from the road surface position to the current position of the tractor is calculated, each calculated travel distance is stored as position information together with the road surface gradient, and the road surface gradient determination means stores each of the travel distances stored in the storage means. A value closest to the separation distance from the preset road surface position of the tractor to the road surface position of the trailer is selected, and the road surface gradient corresponding to the selected movement distance is determined as the road surface gradient on the trailer side .

The invention according to claim 2, in claim 1, comprising a sampling period correcting means for increasing correct sampling period as the vehicle speed of the trailer vehicle is low, the road surface gradient estimating means and storage means, corrected by sampling period correcting means The processing is executed based on the sampling period.

According to a third aspect of the present invention, in the first or second aspect , the vehicle weight estimation means for estimating the vehicle weight, the vehicle weight estimated by the vehicle weight estimation means and the tractor side and trailer side determined by the road surface gradient determination means Start stage selection means for selecting, as the start stage, a shift stage that can achieve the driving force required for the tractor when starting the vehicle, based on the road surface gradient.
According to a fourth aspect of the present invention, the vehicle according to any one of the first to third aspects further comprises a slope start assisting means for holding the vehicle in a braking state when the vehicle is temporarily stopped on an uphill road and releasing the braking state when the vehicle starts by depressing an accelerator. The auxiliary means determines the release timing of the braking state at the start of the vehicle based on the vehicle weight estimated by the vehicle weight estimating means and the road surface gradient on the tractor side and trailer side determined by the road surface gradient determining means. .
According to a fifth aspect of the present invention, in the first to fourth aspects, when the predetermined stop condition is satisfied when the vehicle is temporarily stopped, the engine that is the vehicle driving power source is stopped, and when the predetermined start condition is satisfied, the engine is stopped. The stop condition is established when the tractor side and trailer side road surface gradients determined by the road surface gradient determination unit are equal to or greater than a predetermined stop prohibition determination value. Even so, the operation of the engine is continued.

As described above, according to the road surface gradient estimating apparatus for a trailer vehicle according to the first aspect of the present invention, the road surface gradient estimated sequentially for each sampling period by the road surface gradient estimating means provided in the tractor while the trailer vehicle is running. , and stored in respective storage means together with the moving distance relative to the position of the moving distance based current tractor of the tractor during the sampling period, during a stop of the trailer vehicle, the latest road gradient estimated tractor is positioned A road surface gradient in which the trailer is located is determined by selecting a value closest to the separation distance from the tractor to the trailer from among the travel distances stored in the storage means as well as determining the road surface gradient. As confirmed.
That is, in the trailer vehicle, the trailer follows the track of the tractor, so that the road surface corresponding to the current road surface position of the tractor in the past road surface gradient estimated by the road surface gradient estimation means provided in the trailer. There is a gradient. Therefore, it is possible to sequentially store position information based on the current tractor position along with the road surface gradient while the vehicle is running, and to select a road surface gradient corresponding to the trailer position based on each position information when the vehicle stops. As a result, not only the road surface gradient where the tractor is located but also the road surface gradient where the trailer is located can be appropriately estimated, and these road surface gradients can be used for various controls.

In addition, it is possible to improve the estimation accuracy by accurately determining the road surface gradient where the trailer is located based on the moving distance, and because it is processing for each sampling period, it is performed at low cost without requiring high computing capacity and memory capacity can do.
According to the road surface gradient estimating apparatus for a trailer vehicle of the invention of claim 2 , in addition to claim 1 , the sampling period is increased and corrected as the vehicle speed of the trailer vehicle is lower. In a situation where the vehicle is traveling at a low speed, the distance between the movement distances is narrowed more than necessary, and therefore, even the longest movement distance does not reach the separation distance, and the road surface gradient on the trailer side cannot be determined. Since the movement distance of the same length as that during normal traveling is calculated by increasing the sampling period, the road surface gradient on the trailer side can be determined from the movement distance closest to the separation distance. As a result, the road surface gradient on the trailer side can always be reliably estimated regardless of the vehicle speed of the trailer vehicle.

According to the trailer vehicle road surface gradient estimating apparatus of the third aspect of the present invention, in addition to the first or second aspect , the drive required for the tractor when the vehicle starts based on the vehicle weight and the road surface gradient on the tractor side and the trailer side. The gear stage that can achieve the power is selected as the starting stage. Therefore, the vehicle can be started quickly and smoothly by selecting the optimum start stage.
According to a trailer vehicle road surface gradient estimation device of a fourth aspect of the invention, in addition to the first to third aspects, the braking state release timing at the start of the vehicle based on the vehicle weight and the road surface gradients on the tractor side and trailer side. I decided to decide. Therefore, braking can be released at an appropriate timing, and wasteful fuel consumption due to the rearward movement of the vehicle or the competition between the driving force and the braking force can be reliably prevented.
According to the road surface gradient estimation device for a trailer vehicle of the invention of claim 5 , in addition to claims 1 to 4, when the road surface gradient on the tractor side and the trailer side is equal to or greater than the stop prohibition determination value, the stop condition is established. The engine was kept running. Therefore, it is possible to accurately determine whether or not the engine can be automatically stopped, and thus it is possible to reliably prevent backlash when starting the vehicle when the engine is stopped on a steep uphill road.

1 is an overall configuration diagram showing a drive system of a trailer vehicle to which a road surface gradient estimation device of an embodiment is applied. It is a front view which shows the trailer vehicle when it stops on the road surface of a single gradient. It is a flowchart which shows the movement distance and road surface gradient update routine which ECU performs. It is a flowchart which shows the road surface gradient determination routine which ECU performs. It is explanatory drawing which shows the update condition of the movement distance and road surface gradient during vehicle travel. It is explanatory drawing which shows the fixed condition of the road surface gradient by the trailer side at the time of a vehicle stop. It is a front view which shows a trailer vehicle when a vehicle stops with the attitude | position which located the tractor side on the steep slope. It is a front view which shows a trailer vehicle when a vehicle stops with the attitude | position which located the tractor side on the horizontal path.

Hereinafter, an embodiment of a road surface gradient estimating 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 the road surface gradient estimation apparatus 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 the operation amount Acc of the accelerator pedal 26, and the 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 an acceleration sensor 33 (road surface gradient detecting means) that is mounted on the tractor A and detects the longitudinal acceleration Gs. Sensors such as are connected.

  The output side of the ECU 21 is connected to the electromagnetic valve 9 of the clutch device 2, the electromagnetic valves of the gear shift unit 14, the braking device 34 of the vehicle, the starting device (cell motor) 35 of the engine 1, and the like. Although not, a fuel injection valve of the engine 1 is also 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 Acc 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.

  Further, the ECU 21 executes the automatic transmission mode when the lever position sensor 24 detects that the change lever 13 is switched to the D range, and based on the accelerator operation amount Acc 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 gradient of the road surface on which the vehicle is located when the vehicle is stopped, as will be described later, and the start road automatic selection function, the slope start assist function, and the estimated road surface gradient. It is used for each control of the idle stop start function.
The road surface gradient estimation process 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. The road surface gradient θ is estimated based on the longitudinal acceleration Gs.

Since the start stage automatic selection function, the slope start assist function, and the idle stop start function are well known, only the outline will be described here.
The start stage automatic selection function is a function for selecting an optimal start stage according to the road surface gradient. First, the current vehicle weight (the weight of the tractor A + the trailer B) is estimated (vehicle weight estimation means), and the start stage is selected based on the vehicle weight and the road surface gradient (start stage selection means). The selected start stage is set as the target shift stage, and when starting the vehicle, the vehicle starts with the optimum shift stage that has been switched in advance based on the target shift stage, so that the vehicle can start quickly and smoothly even on difficult uphill roads. Is possible. 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.

  The slope start assist function operates the braking device 34 when the vehicle is temporarily stopped on an uphill road to hold the vehicle in a braking state, and stops the braking device 34 when the vehicle starts by depressing the accelerator to release the braking state. Yes (slope start assisting means), a function that eliminates the troublesome brake operation when starting on an uphill road. Since the optimal timing of brake release differs according to the road surface gradient during stopping, the optimal brake release timing is determined based on the road surface gradient.

The idle stop start function automatically stops the engine 1 when a predetermined stop condition such as a brake operation is satisfied during a temporary stop such as waiting for a signal, and when the predetermined start condition such as stop of the brake operation is satisfied, the engine 35 is operated by the starter 35. 1 is a function for automatically starting 1 (idle stop start means). This function has the effect of reducing fuel consumption and exhaust gas problems caused by idling. However, if the engine 1 is automatically stopped on a steep uphill road, the engine immediately after starting is different from the normal starting when starting thereafter. Since the vehicle is started by 1, there is a case where a predetermined driving force cannot be obtained and a rearward movement of the vehicle occurs.
This phenomenon may not be completely avoided even when the slope start assist function is used in combination. Therefore, in the idle stop start function, when the road surface gradient is equal to or greater than a preset stop prohibition determination value, automatic stop of the engine 1 is prohibited (operation continues) even if the stop condition is satisfied.

As described above, the estimated road surface gradient is used for various controls. As described in [Problems to be Solved by the Invention], the trailer vehicle stops across two different road surface gradients. In this case, there is a problem that the road surface gradient on the side of the tractor A on which the acceleration sensor 33 is mounted is estimated as the road surface gradient of the entire trailer vehicle although it is necessary to consider each road surface gradient.
By the way, because trailer B always follows the traveling locus of tractor A by towing tractor A, trailer B travels on the road surface on which tractor A has traveled after a predetermined time (when it has moved by a separation distance L0 described later). Will do. Therefore, the road surface gradient θ on the tractor A side estimated from the longitudinal acceleration Gs, Gv and the like can be regarded as the road surface gradient θ on the trailer B side after a predetermined time. Based on such knowledge, in this embodiment, the road surface gradient on the trailer B side is estimated separately from the tractor A side, and the road surface gradient estimation process will be described in detail below.

The ECU 21 executes the moving distance / road surface gradient update routine shown in FIG. 3 at a predetermined control interval when the ignition switch of the vehicle is turned on.
First, in step S1, it is determined whether or not the vehicle is traveling. If No (No), the routine is temporarily terminated. If the determination in step S1 is Yes (positive), the process proceeds to step S2, and it is determined whether a preset sampling cycle DT (for convenience, 1 sec in the following description) has elapsed since the previous estimation of the road surface gradient θ. If it has not yet elapsed, a determination of No is made and the routine is terminated. When the sampling period DT has elapsed from the previous estimation process, or when the previous estimation process does not exist at the beginning of the routine, the determination of Yes is made in step S2 and the process proceeds to step S4.

In step S4, as the road surface gradient θ estimation process, the road surface gradient θ is estimated based on the vehicle longitudinal acceleration Gv obtained from the vehicle speed V and the longitudinal acceleration Gs detected by the acceleration sensor 33 (road surface gradient estimating means). The estimated road gradient θ means the gradient of the road surface on which the tractor A side is currently located. In the subsequent step S6, the vehicle speed V detected by the vehicle speed sensor 28 is multiplied by 1 sec to calculate the distance L that the trailer vehicle has moved in 1 sec.
In the ECU 21, 20 storage areas for the movement distances L1 to L20 are set in advance, and 20 storage areas for the road surface gradients θb1 to θb20 are set so as to correspond to the movement distances L1 to L20. . For example, L1 and θb1 are the latest data (excluding real-time road surface gradient θ) 1 sec ago, which means that the road surface gradient at the rear position of the vehicle by the moving distance L1 from the current position of tractor A is θb1, L20 and θb20 are the oldest data 20 seconds before, and mean that the road surface gradient at the rear position by the moving distance L20 from the current position of the tractor A is θb20. In other words, the movement distances L1 to L20 represent the distances from the road surface position where the corresponding road surface gradients θb1 to θb20 are estimated to the current position of the tractor A.

In the subsequent step S8, processing for updating each data of the movement distances L1 to L20 and the road surface gradients θb1 to θb20 stored in each storage area is executed (storage means), and then the routine is ended.
Specifically, the travel distance L1 is updated to the travel distance L newly calculated in step S6, and the road surface gradient θb1 is updated to the newly estimated road surface gradient θ in step S4. Further, the travel distances L2 to L20 are updated to values obtained by adding the travel distance L to the previous values L1 to L19 (for example, L2 is updated to L1 + L, and L20 is updated to L19 + L), and the road surface gradient θb2 to θb20 is updated. Each is updated to a new value for 1 second (for example, θb2 is updated to θb1, and θb20 is updated to θb19).

On the other hand, the ECU 21 executes a road surface slope determination routine shown in FIG. 4 at a predetermined control interval in parallel with the routine of FIG.
First, in step S12, it is determined whether or not the vehicle has stopped. If the determination of Yes is made by stopping the vehicle, the process proceeds to step S14, and the latest road surface gradient θ estimated immediately before is determined as the road surface gradient θa on which the tractor A side is located when the vehicle is stopped (road surface gradient determining means). ). In the subsequent step S16, a value that is greater than and closest to the preset distance L0 between the tractor A and the trailer B is selected from the movement distances L2 to L20. Then, the road surface gradients θb1 to θb20 corresponding to the selected moving distances L2 to L20 are determined as the road surface gradient θb on which the trailer B side is located when the vehicle is stopped (road surface gradient determining means), and then the routine is terminated.

The separation distance L0 is a determination value for specifying the road surface position of the trailer B with the road surface position of the tractor A as a reference. There are trailers B of various full lengths, and the wheel base of the trailer vehicle is different depending on the total length of the trailer B, and the distance from the road surface position of the tractor A to the road surface position of the trailer B is different depending on the wheel base. The wheel base in the trailer vehicle is a distance from the rear wheel Aa of the tractor A to the rear wheel of the trailer B as shown in FIG. Therefore, since the road surface position of the trailer B can be specified using the wheel base as an index, when the wheel base of the trailer vehicle is known, the wheel base is set in advance as the separation distance L0.
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, depending on the use and specification of the trailer vehicle, or the control to which the road surface gradient is applied (for example, the above-mentioned start stage automatic selection control, slope start assist control, idle stop start control, etc.), the safety In consideration of the operability, an appropriate value may be set in advance as the separation distance L0.

Next, the road surface gradient θa and θb estimation processing executed based on the above-described processing of the ECU 21 will be described in the case where the trailer vehicle stops over two different road surface gradients.
In the routine of FIG. 3, while the vehicle is traveling, the road surface gradient θ is estimated every 1 second, which is the sampling period DT, and the movement distance L for 1 second is calculated. FIG. 5 is an explanatory diagram showing a data update situation during vehicle travel. As described above, the road surface gradient θ is estimated at the current position of the tractor A, and θb1 is set as the road surface gradient at the rear position by the movement distance L1 from the current position of the tractor A as 1-second past data. Further, θb2 is set as the road gradient at the rear position by the movement distance L2 as the data for 2 seconds in the past, and θb3 is set as the road gradient at the rear position by the movement distance L3 as the data for the past 3 seconds.

Although not shown, the movement distances L1 to L20 and the road surface gradients θb1 to θb20 for the past 20 seconds are set in this way, and these data are stored in the corresponding storage areas of the ECU 21. Each time the vehicle travels continuously and a new road gradient θ and travel distance L are calculated every 1 second, each data stored in the storage area is sequentially updated.
Therefore, when the vehicle stops, the road surface gradient θ estimated immediately before it can be regarded as the road surface gradient θa on which the tractor A side is located, and this road surface gradient θ is obtained by the processing of step S14 in FIG. The road surface gradient θa on the tractor A side is determined.
Further, since the road surface position of the trailer B is behind the current road surface position of the tractor A by a distance L0, the road surface gradients θb1 to θb20 corresponding to the rear position are regarded as the gradient θb of the road surface on which the trailer B side is located. be able to. By the process of step S16 in FIG. 4, a value that is larger than and closest to the separation distance L0 is selected from the movement distances L2 to L20, and the road gradients θb1 to θb20 corresponding to the selected movement distances L2 to L20 are trailers. The road surface gradient θb on the B side is determined. As a result, the road surface gradient θb is determined as a gradient slightly behind the road surface on which the trailer B is actually located, and is sufficiently within the allowable error range.

FIG. 6 is an explanatory diagram showing a confirmed state of the road surface gradient on the trailer side when the vehicle is stopped. In this example, the moving distance L3 is selected from the moving distances L2 to L20 based on the separating distance L0, and the road surface gradient θb3 corresponding to the moving distance L3 is determined as the road surface gradient θb on the trailer B side.
The selection of the movement distances L2 to L20 is not limited to the above. For example, a value that is smaller than the separation distance L0 and closest may be selected. In this case, the road surface gradient θb is determined as a gradient slightly ahead of the road surface position of the trailer B. For example, the movement distances L2 to L20 closest to the separation distance L0 may be selected regardless of the magnitude relationship between the movement distances L2 to L20 and the separation distance L0.

The above three types of control are executed based on the road surface gradients θa and θb on the tractor A side and trailer B side determined as described above.
For example, the automatic starting stage selection function is based on the road surface gradients θa and θb on the tractor A side and trailer B side, the weight of the entire vehicle estimated by the above-described vehicle weight estimation process, and the weight of the tractor A that is known in advance. The driving force required for the tractor A when the vehicle starts is estimated, and the starting stage is selected from this driving force.
That is, the weight on the trailer B side can be calculated by subtracting the weight of the tractor A from the weight of the entire vehicle, and acts on the tractor A side and the trailer B side when the vehicle starts based on the respective weights and road surface gradients θa and θb. The driving force corresponding to the sum of these loads is required for the tractor A for starting. Therefore, it is only necessary to calculate the driving force of the tractor A corresponding to the sum of these loads, and select a gear stage that can achieve the driving force as the starting stage.

The same applies to the slope start assist function, and loads acting on the tractor A side and the trailer B side when the vehicle starts are estimated based on the weights on the tractor A side and the trailer B side and the road surface gradients θa and θb. And the timing of the brake cancellation | release at the time of starting on an uphill road should just be determined corresponding to the sum of these loads.
As for the idle stop start function, the road surface gradient of the entire vehicle is estimated from the road surface gradients θa and θb on the tractor A side and the trailer B side, and whether or not the engine 1 can be automatically stopped is determined based on the estimated road surface gradient. The road surface gradient of the entire vehicle may be, for example, the average value of the road surface gradients θa and θb on the tractor A side and trailer B side.

As described above, according to the road surface gradient estimating apparatus for a trailer vehicle according to the present embodiment, focusing on the fact that the trailer B follows the traveling locus of the tractor A, the road surface gradient θ and the moving distance every 1 second during the traveling of the vehicle. L is calculated, and the past travel distances L1 to L20 and the road surface gradients θb1 to θb20 are sequentially updated based on these values. When the vehicle stops, the immediately preceding road surface gradient θ is set to the road surface gradient θa on the tractor A side, and the closest value larger than the separation distance L0 is selected from the past movement distances L2 to L20. The road surface gradients θb1 to θb20 corresponding to the travel distances L2 to L20 are determined as the road surface gradient θb on the trailer B side.
Therefore, as shown in FIG. 6, even when the vehicle stops over two different road gradients, the road gradients θa and θb on the tractor A side and trailer B side can be estimated appropriately. . Then, the road gradients θa and θb estimated in this way are used to select the start stage by the start stage automatic selection function, determine the timing of brake release by the slope start assist function, and determine whether the engine 1 can be automatically stopped by the idle stop start function. Therefore, each control can always be executed in an optimum state.

  Specifically, regarding the start stage automatic selection function, the vehicle can be started quickly and smoothly by selecting the optimum start stage. Further, regarding the slope start assist function, braking can be released at an appropriate timing when the vehicle starts, so that wasteful fuel consumption due to the rearward movement of the vehicle and the competition between the driving force and the braking force can be reliably prevented. In addition, regarding the idle stop start function, it is possible to accurately determine whether or not the engine 1 can be automatically stopped, and thus it is possible to reliably prevent backlash when starting the vehicle when the engine is stopped on a steep uphill road.

  As is clear from the above description, the road surface gradient θ and the movement distance L are calculated, and the past movement distances L1 to L20 and the road surface gradients θb1 to θb20 are updated every sampling period DT. For this reason, the ECU 21 is not required to have a very high calculation capability or memory capacity. For example, it is also possible to calculate the road surface gradient θ and the moving distance L sequentially while the vehicle is traveling and sequentially update them as past values without taking such a processing procedure. However, for that purpose, the ECU 21 requires a remarkably high computing capacity and memory capacity, which may increase the cost due to a change in the specifications of the ECU 21 itself. According to this embodiment, the effect that it can implement at low cost, without requiring the specification change of such ECU21, etc. is also acquired.

By the way, when the vehicle is traveling at a low speed, the distance between the movement distances L1 to L20 is narrowed more than necessary, so even the longest movement distance L20 is less than the separation distance L0, and the road surface gradient θb on the trailer B side cannot be determined. Things happen. As a countermeasure, the sampling period DT may be changed according to the vehicle speed V without using the sampling period DT as a fixed value as described above. Specifically, the sampling period DT is increased and corrected as the vehicle speed V is lower, or the sampling period DT is increased and corrected stepwise when the vehicle speed V falls below a predetermined threshold (sampling period correcting means). .
In this way, when the vehicle is traveling at a slow speed, the processing interval of steps S4 to S8 in FIG. 3 is widened by increasing the sampling period DT. For this reason, since the travel distances L1 to L20 having the same length as that during normal traveling are calculated, the road surface gradient θb on the trailer B side can be determined from the travel distances L1 to L20 closest to the separation distance L0. As a result, regardless of the vehicle speed V of the trailer vehicle, the road surface gradient θb on the trailer B side can always be reliably estimated.

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.
In the above embodiment, the estimated road surface gradients θa and θb are used for each control of the start stage automatic selection function, the slope start assist function, and the idle stop start function. However, the present invention is not limited to these. For example, any control may be omitted, or another control may be added.
Moreover, in the said embodiment, although the movement distance L was computed from the vehicle speed V for every 1 second of the sampling period DT, it is not restricted to this, For example, you may utilize the odometer which counts the integrated distance of a vehicle. Specifically, the odometer values may be sequentially stored for each sampling period DT, and the movement distances L1 to L20 may be calculated from the difference between each odometer value and the current odometer value.

1 Engine 21 ECU
(Road surface gradient estimation means, storage means, road surface gradient determination means, vehicle weight estimation means,
Start stage selection means, slope start assistance means, idle stop start means,
Sampling period correction means)
33 Acceleration sensor (road slope detection means)
A Tractor B Trailer

Claims (5)

In the road surface gradient estimation device for a trailer vehicle capable of individually estimating the gradient of the road surface where the tractor is located and the gradient of the road surface where the trailer is located,
Road surface gradient estimating means provided in the tractor for estimating the road surface gradient;
Storage means for storing road surface gradients sequentially estimated by the road surface gradient estimation means during traveling of the trailer vehicle, together with position information based on the position of the current tractor;
When the trailer vehicle is stopped, the latest road surface gradient estimated by the road surface gradient estimating unit is determined as the gradient of the road surface on which the tractor is located, and the current road surface information is stored on the basis of the position information stored in the storage unit. Road surface gradient determining means for selecting a road surface gradient corresponding to the position of the trailer on the basis of the position of the tractor, and determining the selected road surface gradient as a road surface gradient on which the trailer is located ;
The road surface gradient estimating means estimates the road surface gradient every preset sampling period,
The storage means calculates the moving distance from the road surface position where each road gradient is estimated to the current position of the tractor based on the moving distance of the tractor during the sampling period, and the calculated moving distance. Is stored as the position information together with the road surface gradient,
The road surface gradient determining means selects a value closest to a preset distance from the road surface position of the tractor to the road surface position of the trailer from the travel distances stored in the storage means. A road surface gradient estimation device for a trailer vehicle, wherein a road surface gradient corresponding to a moving distance is determined as a road surface gradient on the trailer side . Sampling period correction means for correcting the sampling period to increase as the vehicle speed of the trailer vehicle is lower,
The road surface gradient estimating means and storage means, road gradient estimating device of the trailer vehicle according to claim 1, wherein the executing the processing based on the sampling period of the corrected by the sampling period correcting means. Vehicle weight estimation means for estimating the vehicle weight;
Based on the vehicle weight estimated by the vehicle weight estimating means and the road surface slopes on the tractor side and trailer side determined by the road surface gradient determining means, a gear stage capable of achieving the driving force required for the tractor when starting the vehicle. The road surface gradient estimating device for a trailer vehicle according to claim 1 or 2 , further comprising a starting stage selecting means for selecting the starting stage as a starting stage. A slope start assisting means for holding the vehicle in a braking state when the vehicle is temporarily stopped on an uphill road and releasing the braking state when the vehicle starts by depressing an accelerator,
The slope start assisting means is configured to release the braking state at the time of starting the vehicle based on the vehicle weight estimated by the vehicle weight estimating means and the road surface slopes on the tractor side and trailer side determined by the road surface slope determining means. The road surface gradient estimating device for a trailer vehicle according to any one of claims 1 to 3 , wherein An idle stop start means for stopping an engine which is a driving power source of the vehicle when a predetermined stop condition is satisfied when the vehicle is temporarily stopped, and starting the engine when a predetermined start condition is satisfied;
The idle stop start means operates the engine even if the stop condition is satisfied when the tractor side and trailer side road surface slopes determined by the road surface slope determination means are equal to or greater than a preset stop prohibition determination value. The road surface gradient estimation device for a trailer vehicle according to any one of claims 1 to 4 , wherein

Images