JP2019034633A - Travel control device, vehicle, and travel control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traveling control device, a vehicle, and a traveling control method capable of improving the fuel consumption by prolonging a coastable time as much as possible. A travel control device includes a road determination unit that determines whether or not a road on which a vehicle travels includes a downhill at which the speed of the vehicle slows down due to coasting, and the road determination unit determines that the road is downhill. If it is determined to include, and the vehicle speed is within the predetermined range, the traveling of the vehicle is switched from the drive traveling to the coasting, and during the coasting, the speed of the vehicle falls outside the predetermined range and the speed of the vehicle falls within the predetermined range. When the road after being out of the range includes a downhill where the speed of the vehicle increases due to coasting, the traveling control unit that continues the coasting without switching the traveling of the vehicle from coasting to drive traveling. Prepare [Selection diagram] Fig. 6

Description

  The present disclosure relates to a travel control device, a vehicle, and a travel control method.

  2. Description of the Related Art Conventionally, a technique for controlling auto-cruise traveling (drive traveling) that maintains a vehicle speed at a preset target speed has been developed. Further, from the viewpoint of improving fuel efficiency, a device that controls inertial traveling (also referred to as “coating”) of a vehicle is proposed on the condition that the vehicle speed is within a predetermined speed range during autocruise traveling. (For example, see Patent Document 1).

JP 2012-219986 A

  However, the slope of the road (especially a general road) has changed variously, and in the apparatus described in Patent Document 1, after starting coasting, the speed of the vehicle is outside the predetermined speed range and coasting ends. There was a problem that the time until the time was short and the effect of improving the fuel efficiency was low. For example, while traveling on a long downhill road (downhill) while traveling on a slightly uphill road (uphill), the speed of the vehicle quickly goes out of the predetermined speed range and the coasting ends. There was a case.

  An object of the present disclosure is to provide a travel control device, a vehicle, and a travel control method capable of improving fuel efficiency by increasing the possible time of inertial travel.

The travel control device according to the present disclosure is:
A road determination unit for determining whether a road on which the vehicle travels includes a downhill in which the speed of the vehicle is decelerated by inertial traveling;
When the road determination unit determines that the road includes the downhill and the speed of the vehicle is within a predetermined range, the driving of the vehicle is switched from driving driving to inertia driving, and during the inertia driving, When the speed of the vehicle is out of the predetermined range and the road after the speed of the vehicle is out of the predetermined range includes a downhill in which the speed of the vehicle is increased by the coasting, the vehicle A travel control unit that continues the coasting without switching the coasting from the coasting to the driving travel;
Is provided.

  A vehicle according to the present disclosure includes the travel control device.

The travel control method according to the present disclosure includes:
Determining whether the road on which the vehicle travels includes a downhill in which the speed of the vehicle is decelerated by inertial travel;
When it is determined that the road includes the downhill and the speed of the vehicle is within a predetermined range, the travel of the vehicle is switched from driving travel to inertial travel, and during the inertial travel, the speed of the vehicle is When the road after the vehicle is out of the predetermined range and the vehicle speed is out of the predetermined range includes a downhill in which the vehicle speed is increased by the coasting, the vehicle travels from the coasting. The inertial running is continued without switching to the driving running.

  According to the present disclosure, it is possible to improve the fuel consumption by increasing the possible traveling time of inertia.

It is a block diagram which shows an example of a structure of the vehicle containing the traveling control apparatus which concerns on this Embodiment. It is a block diagram which shows an example of a structure of the traveling control apparatus which concerns on this Embodiment. It is a figure which shows an example of the road gradient information and driving schedule in a 1st road. It is a figure which shows an example of the road gradient information and driving schedule in a 2nd road. It is a figure which shows an example of the road gradient information and driving schedule in a 2nd road. It is a figure which shows an example of the road gradient information and driving schedule in a 2nd road. It is a flowchart which shows an example of the operation example of the traveling control in a traveling control part.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, the configuration of a vehicle including travel control device 100 according to the present embodiment will be described. FIG. 1 is a block diagram showing an example of a configuration of a vehicle including a travel control device 100 according to the present embodiment. It should be noted that here, the illustration and description will be made with a focus on the parts related to the travel control device 100.

  A vehicle 1 shown in FIG. 1 is, for example, a large vehicle such as a truck equipped with an inline 6-cylinder diesel engine. In the following description, coasting refers to neutral coasting (hereinafter also referred to as “N coasting”) when the gear stage of the transmission is neutral.

  As shown in FIG. 1, a vehicle 1 includes a drive system for driving the vehicle, and includes an engine 3, a clutch 4, a transmission (transmission) 5, a propulsion shaft (propeller shaft) 6, and a differential device (differential gear) 7. , A drive shaft 8 and wheels 9.

  The power of the engine 3 is transmitted to the transmission 5 via the clutch 4, and the power transmitted to the transmission 5 is further transmitted to the wheels 9 via the propulsion shaft 6, the differential device 7, and the drive shaft 8. Communicated. Thereby, the motive power of the engine 3 is transmitted to the wheels 9 and the vehicle 1 travels.

  Moreover, the vehicle 1 has the braking device 40 as a structure of the braking system which stops a vehicle. The braking device 40 includes an auxiliary brake 43 such as a foot brake 41 that provides resistance to the wheels 9, a retarder 42 that provides resistance to the propulsion shaft 6, and an exhaust brake that applies load to the engine 3.

  Further, the vehicle 1 includes an automatic traveling device 2 as a configuration of a control system that controls traveling of the vehicle 1. The automatic travel device 2 is a device that automatically controls the output of the engine 3, the connection / disconnection of the clutch 4, and the speed change of the transmission 5 to automatically travel the vehicle 1, and includes a plurality of control devices.

  Specifically, the automatic travel device 2 includes an engine ECU (engine control device) 10, a power transmission ECU (power transmission control device) 11, a target vehicle speed setting device 13, an increase / decrease value setting device 14, and road information acquisition. It has the apparatus 20, the vehicle information acquisition apparatus 30, and the traveling control apparatus 100. The engine ECU 10, the power transmission ECU 11, and the travel control device 100 are connected to each other via an in-vehicle network so that necessary data and control signals can be transmitted / received to / from each other.

  The engine ECU 10 controls the output of the engine 3. The power transmission ECU 11 controls the connection and disconnection of the clutch 4 and the shift of the transmission 5.

  The target vehicle speed setting device 13 sets the target vehicle speed V when the vehicle 1 automatically travels in the travel control device 100. The increase / decrease value setting device 14 sets the speed decrease value −V1 and the speed increase value + V1 when the vehicle 1 is traveling automatically in the travel control device 100. These values V, −V1 and + V1 are parameters used for the automatic traveling of the vehicle 1.

  The target vehicle speed setting device 13 and the increase / decrease value setting device 14 include, for example, an information input interface such as a display with a touch panel arranged on a dashboard (not shown) of the driver's seat, and accept the setting of the parameters from the driver. The target vehicle speed V, the speed decrease value −V1, and the speed increase value + V1 are appropriately referred to as “setting information”.

  The road information acquisition device 20 acquires road information indicating road conditions and the current position of the vehicle 1 and outputs the road information to the travel control device 100. For example, the road information acquisition device 20 includes a current position acquisition device 21 that is a receiver of a satellite positioning system (GPS), a weather acquisition device 22 that acquires weather during traveling, and surroundings such as a preceding vehicle and a parallel running vehicle. And a surrounding sensor 23 that detects a difference in vehicle speed and a vehicle speed difference.

  The road information preferably includes road gradient information indicating the gradient of each point on the road in consideration of a travel schedule generated by the travel control device 100 (travel control unit 120, see FIG. 2). The road gradient information is, for example, data describing the altitude (road altitude) of the corresponding position in association with the horizontal position (latitude / longitude information, etc.) of each place on the road.

  The vehicle information acquisition device 30 acquires vehicle information indicating the operation content of the driver and the state of the vehicle 1 and outputs the vehicle information to the travel control device 100. For example, the vehicle information acquisition device 30 includes the accelerator sensor 31 that detects the amount of depression of the accelerator pedal, the brake switch 32 that detects whether or not the brake pedal is depressed, the shift lever 33, the turn signal switch 34, and the speed of the vehicle 1. A vehicle speed sensor 35 for detection is included.

  The traveling control device 100 generates a traveling schedule including driving traveling (auto cruise traveling) and N coasting (inertial traveling) based on the setting information, road information, and vehicle information. Then, the travel control device 100 controls each part of the vehicle 1 so that the vehicle 1 travels according to the generated travel schedule. FIG. 2 is a block diagram illustrating an example of the configuration of the travel control device 100.

  As illustrated in FIG. 2, the travel control device 100 includes a road determination unit 110 and a travel control unit 120.

  The road determination unit 110 determines whether or not the road on which the vehicle 1 travels is a predetermined road based on the road information, and outputs the determination result to the travel control unit 120. The predetermined road is a road on which the vehicle 1 can travel N, for example, a road including a downhill.

  The travel control unit 120 generates a travel schedule including driving travel and N coasting, and causes the vehicle 1 to travel according to the generated travel schedule based on the current position of the vehicle 1.

  For example, the traveling control unit 120 realizes traveling at a speed according to the traveling schedule by controlling the fuel injection amount of the engine 3 and the like via the engine ECU 10 during driving traveling. In addition, the traveling control unit 120 disconnects the clutch 4 via the power transmission ECU 11 during N coasting. Moreover, the traveling control unit 120 appropriately controls each part of the braking device 40 to stop the vehicle 1. Details of the travel schedule will be described later.

  The travel control unit 120 performs control to switch the vehicle 1 to either driving travel or N coasting in the generated travel schedule.

  Specifically, when the road on which the vehicle 1 travels is a predetermined road and the speed of the vehicle 1 acquired from the vehicle speed sensor 35 is within a predetermined range, the vehicle 1 is switched from driving travel to N coasting. The traveling control unit 120 switches the vehicle 1 from N coasting to driving traveling when the speed of the vehicle 1 is out of a predetermined range during N coasting.

  The predetermined range is a speed range that is set based on the target speed V when the vehicle 1 is traveling automatically, and is set according to a predetermined road described later.

  The predetermined road having a downhill where N coasting is performed includes a first road including a downhill where the vehicle 1 is accelerated, and a second road including a downhill where the vehicle 1 is decelerated.

  The first road is a road including a downhill where the slope resistance Fs of the slope is smaller than the sum of the air resistance Fa to the vehicle 1 and the rolling resistance Fr to the vehicle 1 (for example, a solid line shown in FIG. 3). 211). When the vehicle 1 is made to coast N on the first road, as shown in FIG. 3, the vehicle 1 is accelerated as it is by N coasting on the downhill portion (between the position Lt and the position L2) as indicated by a solid line 212. Let it run.

  In the case of driving traveling, fuel is continuously injected during N coasting (between position L1 and position L2) (see broken line 213). However, in the case of N coasting, fuel is not injected, so fuel efficiency is improved. Can be made.

  The second road is a road including a gentle downhill in which the gradient resistance Fs is larger than the sum of the air resistance Fa and the rolling resistance Fr (see, for example, the solid line 221 shown in FIG. 4). In the case of the second road, the vehicle 1 decelerates even on a downhill. Therefore, as shown in FIG. 4, when the speed of the vehicle 1 becomes higher than a maximum speed within a predetermined range (V + V1 in FIG. 4) and falls below the maximum speed, the vehicle 1 is made to coast N times.

  In the case of driving traveling, since the speed of the vehicle 1 is controlled to match the target speed, the temporal deceleration amount is relatively large (see the broken line 223). On the other hand, in the case of N coasting, the speed of the vehicle 1 gradually decreases due to the inertial force (see the solid line 222), so that the temporal deceleration amount of the vehicle 1 can be reduced as compared with driving travel. Therefore, since the time until the speed of the vehicle 1 deviates from the predetermined range can be increased, fuel can be saved correspondingly.

  In the first road, for example, the predetermined range is set so that the maximum speed is V + V1 and the minimum speed is V−V1 based on the setting information described above. That is, when the predetermined road is the first road, the traveling control unit 120 has a predetermined range in a range from V + V1 (first speed) higher than the target speed V to V−V1 (second speed) lower than the target speed V. Set.

  On the first road, as shown in FIG. 3, in the case of a road that turns from an uphill to a downhill, as described later, N coasting starts before the top of the uphill. To a range with some degree of increase / decrease.

  However, on the second road, the vehicle 1 decelerates even on a downhill. Therefore, if the minimum speed in the predetermined range is set to V-V1 like the first road, the speed of the vehicle 1 is increased. N coasting is continued until V-V1 is reached.

  If it does in this way, after reaching the minimum speed of the vehicle 1, when switching from N coasting to driving travel, the travel control unit 120 performs control to return to the target speed V. Specifically, in order to increase the speed of the vehicle 1, control is performed to increase the fuel injection amount. As a result, fuel is consumed excessively, and fuel consumption may be deteriorated.

  Therefore, when the predetermined road is the second road, the traveling control unit 120 performs control to make the predetermined range narrower than the first road. Specifically, when the predetermined road is the second road, traveling control unit 120 sets the predetermined range in a range from V + V1 higher than target speed V to target speed V.

  Moreover, the road determination part 110 determines whether it is a 1st road or a 2nd road, when it determines with a road being a predetermined road. The determination of the first road and the second road is performed by comparing the sum of the air resistance Fa and the rolling resistance Fr with the gradient resistance Fs.

  Specifically, when the gradient resistance Fs is smaller than the sum of the air resistance Fa and the rolling resistance Fr, the road determination unit 110 determines that the road is the first road, and the gradient resistance Fs rolls with the air resistance Fa. If it is greater than the sum of the resistance Fr, it is determined that the road is the second road.

  The gradient resistance Fs, air resistance Fa, and rolling resistance Fr are the parts where the current vehicle weight of the vehicle 1 is M, the gravitational acceleration is g, the rolling resistance coefficient of the vehicle 1 is μ, the air resistance coefficient of the vehicle 1 is λ, N Assuming that the average gradient is θ and the speed of the vehicle 1 is V0, the following equations (1) to (3) are used.

  As described above, when the predetermined road is the second road, the target speed V is the lowest speed within the predetermined range. Therefore, when the speed of the vehicle 1 reaches V, the vehicle is switched from N coasting to driving. As a result, in the drive travel control by the travel control unit 120, the speed of the vehicle 1 can be adjusted to the target speed V without injecting extra fuel, and as a result, fuel efficiency can be improved.

  Although not shown, the engine ECU 10, the power transmission ECU 11, and the travel control device 100 are, for example, a CPU (Central Processing Unit), a storage medium such as a ROM (Read Only Memory) storing a control program, and a RAM (Random Access Memory). Each having a working memory and a communication circuit. In this case, for example, the functions of the above-described units constituting the travel control device 100 are realized by the CPU executing the control program. Note that all or a part of the engine ECU 10, the power transmission ECU 11, and the travel control device 100 may be integrally configured.

  Next, the details of the travel schedule used by the travel control unit 120 will be described. FIG. 3 is a diagram illustrating an example of road gradient information and a travel schedule on the first road. FIG. 4 is a diagram illustrating an example of road gradient information and a travel schedule on the second road.

  For example, the travel control unit 120 sequentially generates a travel schedule for a predetermined time length from the current time or for a predetermined travel distance from the current position of the vehicle 1 at regular intervals. First, an example of a travel schedule on the first road including a downhill where the vehicle 1 is accelerated will be described.

  In this travel schedule, for example, a travel average speed is a target speed V, an allowable maximum speed in N coasting is Vmax = V + V1 or less, and an allowable minimum speed in N coasting is Vmin = V−V1 or more. Generated to satisfy the condition.

  The travel control unit 120 generates a travel schedule that actively performs N coasting based on the road gradient information. Further, the traveling control unit 120 switches from driving traveling to N coasting in front of the vertex position on the condition that the speed of the vehicle 1 is equal to or higher than the allowable minimum speed Vmin at the vertex position where the road turns from the uphill to the downhill. A travel schedule including contents is generated.

  As shown in FIG. 3, the road gradient information includes information indicating the road altitude for each horizontal distance (distance) from the current position L0 of the vehicle 1 as indicated by a solid line 211 in FIG. 3, for example. The horizontal distance from the current position L0 of the vehicle 1 can be replaced with the elapsed time from the current time. Also, the road elevation can be replaced with a road gradient from the relationship with the preceding and following road elevations. The road gradient information of the solid line 211 indicates that the current position L0 of the vehicle 1 is in the middle of an uphill, and a downhill exists immediately after the uphill.

  For example, the traveling control unit 120 sequentially determines whether or not there is a portion (top of the slope) that turns from an uphill to a downhill within a predetermined distance range ahead of the road based on the road gradient information. To do.

  Then, when the top of the slope exists, the traveling control unit 120 determines whether the top of the slope can be exceeded with N coasting when switching to N coasting at a position L1 immediately after the current position L0. That is, the traveling control unit 120 calculates whether or not the speed at the top of the slope is equal to or higher than the allowable minimum speed Vmin. The travel control unit 120 performs this calculation based on the current speed V0, the travel resistance coefficient of the vehicle 1 obtained in advance through experiments or the like, and road gradient information.

  When switching to N coasting on the uphill, the speed of the vehicle 1 decreases rapidly. However, when the speed is high or the distance to the top is short enough to maintain the speed equal to or higher than the allowable minimum speed Vmin (V-V1) at the position approaching the downhill, Even when the vehicle is switched to coasting, it is possible to satisfy the traveling condition that the minimum speed in N coasting is equal to or higher than the allowable minimum speed Vmin.

  If the traveling control unit 120 determines that the top of the hill can be exceeded while N coasting, for example, the traveling control unit 120 switches to N coasting immediately after the position L1, and the speed ranges from the allowable minimum speed Vmin to the allowable maximum speed Vmax, that is, ( It is determined to maintain N coasting from position (V−V1) to position L2 that deviates from the range of (V + V1). Then, as indicated by a solid line 212 on the lower side of FIG. 3, the travel control unit 120 generates a travel schedule that switches to N coasting at position L1 and maintains N coasting to position L2.

  Specifically, the traveling control unit 120 uses, for example, the following equation (4) to estimate the speed at the top position Lt when the vehicle 1 performs N coasting to the top position Lt (hereinafter “top estimation”). Vt is calculated.

  Here, M is the current vehicle weight of the vehicle 1, g is the gravitational acceleration, h0 is the altitude of the current position L0 of the vehicle 1, ht is the altitude of the top position Lt, μ is the rolling resistance coefficient of the vehicle 1, and Δx is the current position. The horizontal distance (path) from L0 to the top position Lt, θ is the average gradient of the N coasting portion, and V0 is the speed of the vehicle 1.

  Then, when the calculated summit estimated vehicle speed Vt is equal to or higher than the set allowable minimum speed Vmin, the traveling control unit 120 maintains this when N coasting, and switches to N coasting when driving. To decide. That is, the travel control unit 120 generates a travel schedule as shown by a solid line 212 in FIG. 3, for example, and controls the vehicle 1 according to the travel schedule.

  Such a travel schedule including the N coasting section determined based on the road gradient information effectively improves the fuel efficiency of the vehicle 1. In addition, by driving the vehicle 1 according to the travel schedule, the driver does not need to perform successive accelerator operations.

  Next, a travel schedule under the second condition including a downhill where the vehicle 1 decelerates will be described.

  Such a travel schedule is generated, for example, so as to satisfy the travel condition that the allowable maximum speed in N coasting is Vmax = V + V1 or less and the allowable minimum speed in N coasting is Vmin = V or more.

  Based on the road information, the traveling control unit 120, on the condition that after the road turns from a steep downhill to a gentle downhill, the speed is the allowable maximum speed Vmax or less and the allowable minimum speed Vmin or more. A travel schedule including contents to switch from driving travel to N coasting is generated.

  As shown in FIG. 4, the road gradient information includes information indicating the road elevation for each horizontal distance (road) from the current position L0 of the vehicle 1, for example, as indicated by the solid line 221 on the upper side of FIG. 4. The road gradient information of the solid line 221 indicates that the current position L0 of the vehicle 1 is in the middle of a steep downhill, and the position L3 is a portion that turns from a steep downhill to a gentle downhill.

  The traveling control unit 120 sequentially determines whether or not there is a portion that turns from a steep downhill to a gentle downhill within a predetermined distance range ahead of the road based on the road gradient information. And when the said part exists, the traveling control part 120 determines whether the speed is in the range of V + V1 to V after turning to a gentle downhill or after turning to a gentle downhill. . When the speed is within the range, the traveling control unit 120 shifts from driving to N coasting at a position L3 where the vehicle turns from a steep downhill to a gentle downhill, or at a position where the speed becomes V + V1 or less after the position L3. Switching (see solid line 222).

  As shown by the solid line 222 in FIG. 4, the traveling control unit 120 generates a traveling schedule that switches from the position L3 to the N coasting and maintains the N coasting to the position L4 where the allowable minimum speed V is reached.

  As a result, the speed of the vehicle 1 is decelerated, but since the amount of deceleration is small compared to the speed in driving travel, the time until the speed reaches V, which is the minimum speed, is increased accordingly. That is, since the N coasting time can be lengthened, the fuel consumption during that time is improved.

  By the way, as shown in FIG. 5, there may be a portion (top of the slope) where the second road turns from a steep downhill to a gentle downhill and then turns uphill to downhill. In this case, the traveling schedule is generated so as to satisfy the traveling condition that the allowable maximum speed in N coasting is Vmax = V + V1 or less and the allowable minimum speed in N coasting is Vmin = V or more.

  As shown in FIG. 5, the road gradient information includes information indicating the road elevation for each horizontal distance (road) from the current position L0 of the vehicle 1, for example, as indicated by the solid line 231 on the upper side of FIG. 5. The road gradient information of the solid line 231 indicates that the current position L0 of the vehicle 1 is in the middle of a steep downhill, and the position L1 is a portion that turns from a steep downhill to a gentle downhill. Further, the road gradient information of the solid line 231 indicates that the position L2 is in the middle of an uphill that turns from a gentle downhill, and the position L3 is a portion (the top of the slope) where the position L3 turns from the uphill to a steep downhill. Is shown.

  The traveling control unit 120 sequentially determines whether or not there is a portion that turns from a steep downhill to a gentle downhill within a predetermined distance range ahead of the road based on the road gradient information. And when the said part exists, the traveling control part 120 determines whether a speed is in the range of V + V1 to V after turning to a gentle downhill. When the speed is within the range, the traveling control unit 120 switches from driving traveling to N coasting at a position L1 where the vehicle moves from a steep downhill to a gentle downhill (see a solid line 232). The traveling control unit 120 maintains the speed of the vehicle 1 at V + V1 or lower by controlling each part of the braking device 40 and using an engine brake or the like on a steep downhill from the current position L0 to the position L1. Take control.

  As shown by the solid line 232 in FIG. 5, the travel control unit 120 generates a travel schedule that switches from the position L1 to N coasting and maintains N coasting to the position L2 where the allowable minimum speed V is reached.

  The traveling control unit 120 switches from N coasting to driving traveling at a position L2 (in the middle of the uphill) where the speed of the vehicle 1 has reached the allowable minimum speed V, up to a position L3 where the vehicle goes from the uphill to a steep downhill. Control is performed so that the speed of the vehicle 1 is maintained at the target speed V. That is, as shown by the solid line 232 in FIG. 5, the travel control unit 120 generates a travel schedule that switches to drive travel at the position L2 and maintains the drive travel to the position L3.

  The traveling control unit 120 switches from driving traveling to N coasting at a position L3 where the vehicle travels from an uphill to a steep downhill (see a solid line 232). That is, as shown by the solid line 232 in FIG. 5, the travel control unit 120 switches from the position L3 to N coasting and maintains the N coasting to a position (not shown in FIG. 5) where the allowable maximum speed V + V1 is reached. Is generated.

  However, in the travel schedule shown in FIG. 5, control is performed to increase the fuel injection amount in order to maintain the speed of the vehicle 1 at the target speed V from the position L2 to the position L3. There is a risk that fuel consumption will deteriorate.

  Therefore, in the present embodiment, as shown in FIG. 6, the traveling control unit 120 increases the speed of the vehicle 1 by N coasting on the road ahead after the speed of the vehicle 1 reaches the allowable minimum speed V. When there is a steep downhill, even if the speed of the vehicle 1 reaches the allowable minimum speed V, the N coasting is continued without switching from N coasting to driving. That is, as shown by the solid line 242 in FIG. 6, the traveling control unit 120 does not switch to driving traveling even after the vehicle speed drops below the target speed V at the position L2 after switching from the position L1 to N coasting. Then, a travel schedule is generated that maintains N coasting to a position (not shown in FIG. 6) where the vehicle speed returns to the target speed V due to the acceleration on a steep downhill.

  Thereby, after the speed of the vehicle 1 is out of the predetermined range and switched from N coasting to driving, the time until switching to the next N coasting, more specifically, from position L2 to position L3 in FIG. Since the time of N coasting (that is, the time during which fuel is not injected) can be increased by the time during which the speed of the vehicle 1 is maintained at the target speed V, the fuel consumption during that time can be improved.

  Next, an operation example of travel control in the travel control unit 120 will be described. FIG. 7 is a flowchart illustrating an example of an operation example of the travel control in the travel control unit 120. The process in FIG. 7 is executed when the vehicle 1 is traveling on the second road.

  First, the traveling control unit 120 determines whether to start N coasting (step S100). Specifically, the traveling control unit 120 determines whether or not the position of the vehicle 1 is a portion that turns from a steep downhill to a gentle downhill.

  As a result of the determination, when N coasting is not started (step S100, NO), the process returns to before step S100. On the other hand, when starting N coasting (step S100, YES), the traveling control unit 120 performs control to switch from driving traveling to N coasting (step S102).

  Next, the traveling control unit 120 determines whether or not N coasting is finished (step S104). Specifically, the traveling control unit 120 determines whether or not the vehicle speed has become equal to or lower than the target speed V.

  As a result of the determination, if N coasting does not end (step S104, NO), the process returns to before step S104. On the other hand, when N coasting ends (step S104, YES), the traveling control unit 120 increases the speed of the vehicle 1 by N coasting on the road ahead after the speed of the vehicle 1 reaches the target speed V. It is determined whether or not there is a steep downhill (step S106).

  As a result of the determination, if there is a steep downhill that increases (YES in step S106), it can be estimated that the vehicle 1 returns to the target speed V even if the speed of the vehicle 1 is once lower than the target speed V. Performs control to continue the N coasting without switching from N coasting to driving (step S108). Thereafter, this control ends.

  On the other hand, when there is no steep downhill that accelerates (step S106, NO), the traveling control unit 120 performs control to switch from N coasting to driving traveling (step S110). Thereafter, this control ends.

  As described above in detail, in the present embodiment, the road determination unit that determines whether or not the road on which the vehicle 1 travels includes a downhill (gradual downhill) in which the speed of the vehicle 1 is reduced by inertial traveling. 110 and the road determination unit 110 determines that the road includes a downhill, and the speed of the vehicle 1 is within a predetermined range (from the target speed V in driving travel to the upper limit speed V + V1 set faster than the target speed V). The vehicle 1 travels from driving to coasting (N coasting), and during the coasting, the speed of the vehicle 1 is outside the predetermined range and the speed of the vehicle 1 is within the predetermined range. When the road after going outside includes a downhill (steep downhill) in which the speed of the vehicle 1 is increased by coasting, the coasting of the vehicle 1 is performed without switching from coasting to driving. Continue And a travel control unit 120.

  According to the present embodiment configured as described above, after the speed of the vehicle 1 is out of the predetermined range and switched from N coasting to driving, the time for N coasting is the time until switching to the next N coasting. Since (that is, the time during which fuel is not injected) can be lengthened, the fuel consumption during that time can be improved.

  In addition, each of the above-described embodiments is merely an example of actualization in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.

  The present disclosure is useful as a travel control device, a vehicle, and a travel control method capable of improving fuel efficiency by increasing the possible time of inertial travel.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Automatic traveling device 3 Engine 4 Clutch 5 Transmission 6 Propulsion shaft 7 Differential device 8 Drive shaft 9 Wheel 10 ECU for engine
11 Power transmission ECU
DESCRIPTION OF SYMBOLS 13 Target vehicle speed setting apparatus 14 Increase / decrease value setting apparatus 20 Road information acquisition apparatus 21 Current position acquisition apparatus 22 Weather acquisition apparatus 23 Ambient sensor 30 Vehicle information acquisition apparatus 31 Accelerator sensor 32 Brake switch 33 Shift lever 34 Turn signal switch 35 Vehicle speed sensor 40 Braking Device 41 Foot brake 42 Retarder 43 Auxiliary brake 100 Travel control device 110 Road determination unit 120 Travel control unit

Claims (5)

A road determination unit for determining whether a road on which the vehicle travels includes a downhill in which the speed of the vehicle is decelerated by inertial traveling;
When the road determination unit determines that the road includes the downhill and the speed of the vehicle is within a predetermined range, the driving of the vehicle is switched from driving driving to inertia driving, and during the inertia driving, When the speed of the vehicle is out of the predetermined range and the road after the speed of the vehicle is out of the predetermined range includes a downhill in which the speed of the vehicle is increased by the coasting, the vehicle A travel control unit that continues the coasting without switching the coasting from the coasting to the driving travel;
A travel control device comprising: The predetermined range is a range from a target speed in the driving travel to an upper limit speed set faster with respect to the target speed.
The travel control device according to claim 1. During the coasting, the travel control unit increases the speed of the vehicle on the road after the speed of the vehicle is out of the predetermined range and the speed of the vehicle is out of the predetermined range. When the vehicle does not include a fast downhill, the vehicle travel is switched from the inertia travel to the drive travel;
The travel control apparatus according to claim 1 or 2.   A vehicle comprising the travel control device according to any one of claims 1 to 3. Determining whether the road on which the vehicle travels includes a downhill in which the speed of the vehicle is decelerated by inertial travel;
When it is determined that the road includes the downhill and the speed of the vehicle is within a predetermined range, the travel of the vehicle is switched from driving travel to inertial travel, and during the inertial travel, the speed of the vehicle is When the road after the vehicle is out of the predetermined range and the vehicle speed is out of the predetermined range includes a downhill in which the vehicle speed is increased by the coasting, the vehicle travels from the coasting. A travel control method for continuing the inertia travel without switching to the drive travel.

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