JP2022183407A - Energy-saving deceleration travel control method - Google Patents

Abstract

To enable a practical use by solving/reducing a main problem of energy-saving deceleration travel of an inertia travel main object to a target deceleration/stop point of a vehicle.SOLUTION: Deceleration travel of a travelling vehicle to a target deceleration/stop point such as an intersection and cross walk in a constant speed range is performed on the basis of combination of inertia travel from a point of a target deceleration/stop point upstream constant distance at a speed within an inertia travel transit tolerance limit and brake travel (or constant speed travel and brake travel) continuous with the inertia travel.SELECTED DRAWING: Figure 3

Description

The invention of the present application efficiently and effectively utilizes the kinetic energy of the vehicle when the vehicle decelerates to decelerate the vehicle. , and relates to an energy-saving deceleration control method with excellent kinetic energy utilization efficiency.

When decelerating a running vehicle, the running mode in which the kinetic energy of the vehicle immediately before the start of deceleration can be most effectively utilized for deceleration running is coasting.
However, coasting does not unconditionally lead to effective use of kinetic energy.
For example, as shown in FIG. 1, the vehicle coasts between speed (vc+Δv) and speed (vc−Δv) (distance d11), and then accelerates between speed (vc−Δv) and speed (vc+Δv) (distance d12). In this case, the traveling distance d1 (=d11 +d12) during this period will be the same kinetic energy consumption as traveling at the speed vc, ie, the same kinetic energy consumption as the constant speed traveling at the speed vc, and energy-saving traveling will not be achieved.
On the other hand, as shown in FIG. 2, in the unit traveling section traveling, in the deceleration traveling at the braking deceleration αb from P4 to P6, the distance between P4 and P6 is the traveling distance with the kinetic energy Evc, and the traveling distance from P3 to P5 The distance between P3-P5-P6 of the inertia running with the inertia running deceleration αi and the braking running with the braking deceleration αb from P5 to P6 is the running distance with the kinetic energy Evc, and the distance between P3-P4 is the coasting running. Energy-saving mileage due to
That is, the kinetic energy Evc=(m・Energy-saving deceleration running that makes effective use of vc ² /2) becomes possible.
In other words, when a fixed target point for deceleration/stopping (an intersection, a slow-down point such as a pedestrian crossing, an obstacle in front of the traveling road, etc.) is specified, the inertial travel distance that maximizes the kinetic energy of the vehicle is calculated. is calculated, and energy-saving/low-CO2 emission deceleration running is enabled by coasting from a point within the upstream inertia travelable distance of the target point to the target deceleration/stop point.

However, when executing inertia running by the above inertia running distance,
1) The coasting start point is several hundred meters or more upstream from the target deceleration/stop point, that is, the coasting distance becomes excessive.
2) Therefore, the average running speed during this period is much lower than the running speed (constant running speed) before transition to inertial running.
3) In order to specify the coasting distance, it is necessary to specify the coasting deceleration of each vehicle at that time, and therefore to specify the running resistance. It is practically difficult to obtain. ,
4) Dealing with changes in the running environment such as road conditions after shifting to coasting, such as changes in the road gradient, resulting in changes in the coasting speed.
etc.

To solve the above problems 1) and 2), a method of decelerating to the target deceleration/stop point by efficiently and effectively combining inertia running and braking running has been considered. (Patent Literature 1, Patent Literature 2, Patent Literature 3) That is, when the inertia running start speed is vc and the inertia running end speed is vb, the vehicle speed at the start of inertia running and at the end of inertia running (at the start of braking running) is The kinetic energies Ec and Eb possessed are represented by (Equation 1) and (Equation 2), respectively.
(Number 1)
Ec=m.vc2/ ²
(Number 2)
Eb = m·vb ^2/2
where m: vehicle (including passengers) mass.
Therefore, the kinetic energy utilization efficiency ηcb between the inertia running start speed vc and the inertia running end speed vb is
(Number 3)
ηcb = (vc ² – vb ² )/vc ²
Also, the average speed vcb during the coasting is
(Number 4)
vcb≈(vc+vb)/2
becomes.
Therefore, if vc = 60 km/h and vb = 30 km/h, for example,
ηcb = 0.75
vcb≈45km/h
can be
That is, by appropriately setting vc and vb, it is possible to keep both the kinetic energy utilization efficiency and the average speed during coasting within the permissible range in deceleration running due to coasting.

However, regarding the identification of the inertia travel distance in 3) above, all of the methods of Patent Document 1, Patent Document 2, and Patent Document 3 provide a method of temporarily setting the inertia travel distance and learning and correcting it by actual inertia travel. However, both methods have the problem that the learning/correction and the control based on the result thereof are complicated in practical use.

On the other hand, in the case of conventional deceleration running, in which all deceleration is performed by braking, the problem of increasing the deceleration running distance due to inertia running is eliminated, but the kinetic energy utilization efficiency is greatly reduced.
In addition, even in regenerative cooperative braking, which regenerates kinetic energy and utilizes it for subsequent driving, part of the kinetic energy is consumed by the friction braking that is also used. There is a problem that the kinetic energy utilization efficiency is inferior to that of coasting, such as insufficient charging efficiency due to insufficient characteristics of capacity secondary battery power density or temperature characteristics.

JP 2013-177126 JP 2019-034734 Patent No. 6788942

The invention of the present application has the biggest problems in utilizing the kinetic energy of a running vehicle for decelerating mainly due to inertia. 3) Accurate identification and control of coasting deceleration is complicated, and 4) Driving environment changes during coasting can be solved rationally and simply. Alternatively, the present invention provides an energy-saving deceleration running control method based on inertia running, which comprehensively surpasses the conventional method of utilizing kinetic energy by regenerative cooperative braking by reducing energy consumption.

Here, inertia running refers to running in which the transmission of the power of the vehicle drive source to the driving wheels is interrupted or sparse. (However, it is not always necessary to stop the driving force of the vehicle. For example, it is not always necessary to stop the engine in a gasoline engine vehicle, that is, to cut fuel. A corresponding energy saving effect can be obtained by reducing
In addition, even if the transmission of the power of the vehicle drive source to the drive wheels is not completely cut off (that is, the clutch is not cut), for example, the vehicle drive source can set the accelerator off state at MT 4th speed to "pseudo coasting". Even with a configuration in which power is sparsely transmitted to the drive wheels, a corresponding energy saving effect can be obtained.

The basic idea of the present invention will be described below with reference to FIG.
In FIG. 3, a straight line P4-P6 indicates a braking deceleration straight line at a braking deceleration αb from a point P4 to a point P6 of a constant speed running vehicle at the running speed vcmax.
That is, the vehicle traveling at a constant speed at the speed vcmax normally travels at a constant speed to the point P4, and then brakes from the point P4 toward the stop point P6 at the braking deceleration αb. As a result, the kinetic energy possessed by the vehicle running at the speed vcmax is all consumed in the braking run between the points P4 and P6, and the kinetic energy utilization effect of the vehicle during this period, that is, the running distance between the points P4 and P6 is distance only.
On the other hand, in the energy-saving deceleration running according to the present invention, the vehicle running within the inertial running transition allowable speed range, that is, the range of speed vcmin to speed vcmax, starts normal running ( (acceleration or constant speed) to coasting (for deceleration).

As shown in FIG. 3, the vehicle that coasts past the point P3 within the allowable speed range for transition to inertia running from speed vcmin to speed vcmax performs coasting at speed vcmin or higher, and after reaching speed vcmin, starts at speed vcmin. Constant speed running is performed up to the braking start point P4, after which the vehicle reaches the target deceleration/stop point P6 by braking running at the braking deceleration αb.
Here, the distance between point P5 and point P6 is the braking travel distance from speed vcmin to speed 0, that is, db=(vcmin ² /(2·αb)).
Further, the vehicle passing the point P3 at a speed less than vcmin continues to run at a constant speed while maintaining the speed at which it passed the point P3 until the braking deceleration straight line P4-P6.

At the point P3, if the inertia running speed becomes equal to or higher than the inertia running transition speed vc for some reason (such as a road gradient) after the normal running is shifted to the inertia running at the inertia running transition speed vc, the inertia running is stopped. After that, it shifts to normal running and runs at speed vc up to the braking running transition point (distance db = {vc ² / (2 · αb)} from the target deceleration stop point), and after that, braking running at deceleration αb to reach point P6.

Here, the distance dr between the point P3 and the point P6 is preferably the coastable distance at the speed vcmax from the viewpoint of kinetic energy utilization efficiency. If the kinetic energy utilization efficiency of deceleration running or the average speed during coasting are both within the allowable range, the distance is not necessarily the coastable running distance.
That is, the problem 3) is that the inertia running result from the inertia running start point P3 provisionally specified in advance is not learned and corrected by actual running of the temporary inertia running distance every time the inertia running is performed, and the kinetic energy is used. If the efficiency and the average speed during coasting are within the allowable range, the coasting start point P3 at the speed vcmin to the speed vcmax can be made a fixed distance dr upstream from the point P6.

As a result, according to the present invention, the allowable inertia travel distance during deceleration travel mainly due to inertia travel is set to the actual inertia travel distance by setting the provisional inertia travel distance, as shown in Patent Document 1, Patent Document 2, and Patent Document 3. It is no longer necessary to specify and control accurately like learning, updating, and control by.
However, in this case, as described above, the utilization efficiency of kinetic energy due to coasting or the running speed during this period is sacrificed to some extent within the allowable range.

Illustration of the energy saving effect of coasting Explanatory drawing of running condition of unit running section Explanatory diagram of the basic concept of the energy-saving deceleration control method according to the present invention It is an example of a processing procedure in the energy-saving deceleration control support device according to the present invention.

The energy-saving deceleration control method according to the present invention can be realized by partially improving the current car navigation system having route search/guidance functions.
Specifically, a route search is performed from the departure point to the destination, and based on the results, (multiple) unit travel sections from the departure point to the destination are specified, and the target deceleration/stop point positions in each unit travel section are determined. Information is specified and obtained, and distance information between the current position of the vehicle and the target deceleration stop point is obtained from the periodic speed information and position information acquisition results of the vehicle in each unit travel section, and the coasting or braking support is obtained. must have the ability to

In addition, as described above, the present invention provides an energy-saving deceleration control method for manually operated vehicles (vehicles driven by a driver) of current gasoline/diesel vehicles or electric vehicles such as EVs by partially improving the above-mentioned current car navigation system. It is also effective as a support device for such devices, and can of course also be applied to automatic driving vehicles.

FIG. 4 shows an example of processing procedures in the energy-saving deceleration control method and its support device according to the present invention.
However, in this procedure example, after the vehicle intended to travel within a single unit travel section specifies the target deceleration/stop point, it shifts to deceleration mainly due to inertia and then stops at the target deceleration/stop point. It is limited to procedures.
Also, during this procedure, the vehicle speed and current vehicle position information shall be determined periodically in the background with the required frequency and accuracy.

In FIG. 4,
401 is the starting point of this procedure example;
402 is point P6 identification determination processing for determining whether or not the (next) target deceleration/stop point position (point P6 in FIG. 3) of the vehicle has been identified;
403 is point P4 identification processing for identifying point P4 when it is determined in processing 402 that the target deceleration/stop point (point P6) has not yet been identified;
404 is a dr identification process for identifying a coasting transition point that is a fixed distance dr upstream of the P6 point;
405 is a d calculation/specification process for calculating/specificating the distance d between the current position of the vehicle and P4;
406 is an inertia running shift determination process for comparing the distance dr specified in the process 404 and the distance d calculated and specified in the process 405 to determine whether or not the inertia running shift can be performed;
407 is a normal running process in which normal running (acceleration running or constant speed running) is performed when the inertia running transition decision in process 406 is "no";

408 is an inertial running transition speed determination process for determining whether or not the vehicle speed v is within the inertial running transition possible speed range vcmin to vcmax when the inertia running transition possibility determination is "Yes" in the process 406;
In step 409, if it is determined in step 408 that the vehicle speed v is within the range of speeds that allow inertia travel, i.e., if v=vc, then inertia travel processing is performed to transition to inertia travel or continue inertia travel.
410 is v>vc determination processing for determining whether or not the vehicle speed exceeds the inertia transition speed vc;
In step 411, when the vehicle speed v is determined to be v>vc in step 410, a constant speed transition process is performed to stop coasting and shift to constant speed driving at speed v=vc.
In step 412, as a result of the processing 411, a braking travel transition possibility determination processing is performed to determine whether or not the remaining distance d to the point P6 has become a braking travel transition distance of ^vc2 /(2·αb) or less.
413 is the distance d from the current position of the vehicle to P6 should start braking at the current speed v.
braking start determination processing A for determining whether or not d≦{v ² /(2·αb)} has been reached;
In step 414, as in step 413, the distance d from the current position of the vehicle to P6 is the distance db at which braking should start.
Braking start determination process B for determining whether or not {v ² /(2·αb)} has been reached;
415 is a vcmin constant speed running process for carrying out constant speed running at a speed vcmin when it is determined in the process 414 that the distance d from the current position of the vehicle to P6 has not reached the distance db at which braking should be started;
At 416, it is determined in processing 413 or processing 414 that the distance d from the current vehicle position to P6 has reached the distance db≤{ ^v2 /(2·αb)} where braking should start from the current speed v. In the case, braking travel processing for braking the braking deceleration αb,
417 is the target deceleration/stop for determining whether or not the distance d from the current position of the vehicle to P6 has reached d=0, that is, the target deceleration/stop position (point P6 in FIG. 3) as a result of the braking run by the process 416 Point position reach determination processing,
418 is final destination determination processing for determining whether or not the target deceleration/stop point position determined in processing 417 is the final destination of the main run;
419 is the end point of this processing procedure for ending this processing procedure when it is determined that the final destination has been reached in processing 418;
is.

By the present invention, instead of the regenerative coordinated running for the purpose of utilizing kinetic energy during deceleration, which is currently adopted in hybrid vehicles or electric vehicles, the inertia of the kinetic energy possessed by the vehicle can be used even in gasoline engine vehicles / diesel engine vehicles. Efficient and effective use is possible with simple calculation and control for deceleration running, which is mainly for running.
That is, the present invention is a simple driving system that efficiently uses kinetic energy instead of conventional braking or regenerative cooperative braking in any vehicle, regardless of the driving mode of the vehicle and the driving mode of automatic driving/manual driving. This enables effective energy-saving and greenhouse gas reduction deceleration driving.
Further, the present invention can also be implemented by providing the coasting start signal and the braking start signal to the vehicle from the infrastructure side without providing assistance from the car navigation system.
In addition, in the vicinity of the point P5 (inertia running end point) in FIG. Alternatively, sensors such as cameras mounted on the vehicle can be used to detect when the traffic light is green or when it is confirmed that there are no pedestrians on the crosswalk, the vehicle will shift from coasting or constant speed to braking. It is also possible to stop the transition, maintain the vehicle running speed v at that time, and continue running toward the next deceleration/stop point after passing point P6 (target deceleration/stop point).

In Figures 1 and 2, P1: Start/acceleration start point P2: Acceleration end point, constant speed running start point P3: Inertia running start point P4: Constant speed running end point, braking start point P5: Inertia running end point, Braking running start point P6: Braking running end point d11: Inertia running distance d12: Acceleration running distance d1: (Inertia running + Acceleration running) Traveling distance during one cycle αa: Acceleration αb: Braking deceleration αi: Inertia running deceleration chart 3, FIG. 4, and (Formula 1) to (Formula 4) P3: Inertial running start point between vehicle running speeds vcmax to vcmin P34: Inertial running start speed vc3 Vehicle inertial running end/constant speed running start point P4: Braking start point P45 from vehicle speed vcmax: Inertia start speed vc2 Vehicle inertia end point P5: Inertia start speed vc2 / Braking start point: Braking start from vehicle speed vcmin Point P6: Target deceleration/stop point ηcb: Kinetic energy utilization efficiency due to inertia v: Vehicle running speed (including constant speed running, inertial running, and braking running speeds)
vc: Inertia running transition (start) speed vc1, vcmax: Inertia running transition allowable upper limit speed vc2, vc3: Inertia running transition allowable speed vc4, vcmin: Inertia running transition allowable lower limit speed vb: Braking start speed vcb: During inertia running Average speed αi: Inertia deceleration αb: Braking deceleration d: Distance between current point and target deceleration/stop point dr: Inertia start constant distance upstream of target deceleration/stop point db: Braking upstream of target deceleration/stop point Start distance dbmax=vcmax ² /(2·αb): Braking distance from speed vcmax dvmin=vcmin ² /(2·αb): Braking distance from speed vcmin

To solve the above problems 1) and 2), a method of decelerating to the target deceleration/stop point by efficiently and effectively combining inertia running and braking running has been considered. (Patent Literature 1, Patent Literature 2, Patent Literature 3) That is, when the inertia running start speed is vc and the inertia running end speed is vb, the vehicle speed at the start of inertia running and at the end of inertia running (at the start of braking running) is The kinetic energies Ec and Eb possessed are represented by (Equation 1) and (Equation 2), respectively.
(Number 1)
Ec=m.vc2/ ²
(Number 2)
Eb = m·vb ^2/2
where m: vehicle (including passengers) mass.
Therefore, the kinetic energy utilization efficiency ηcb between the inertia running start speed vc and the inertia running end speed vb is
(Number 3)
ηcb = (vc ² - vb ² )/vc ²
Also, the average speed vcb during the coasting is
(Number 4)
vcb≈(vc+vb)/2
becomes.
Therefore, if vc = 60 km/h and vb = 30 km/h, for example,
ηcb = 0.75
vcb≈45km/h
can be
That is, by appropriately setting vc and vb, it is possible to keep both the kinetic energy utilization efficiency and the average speed during coasting within the permissible range in deceleration running due to coasting.

In order to solve the problems 1) and 2) above, methods have been conceived that use an efficient and effective combination of inertia running and braking running for deceleration running up to target deceleration/inertia running (Patent Document 1, Patent Document 2, Patent Document 3). That is, if the inertia start speed is vc and the inertia end speed is vb, the kinetic energies Ec and Eb possessed by the vehicle at the start of the inertia run and at the end of the inertia run (at the start of the braking run) are respectively (Equation 1), (Equation 2).
(Number 1)
Ec=m.vc2/ ²
(Number 2)
Eb=m.vb2/ ²
Here, m: Vehicle (including passenger) mass Therefore, the kinetic energy utilization efficiency ηcb between the inertia running start speed vc and the inertia running end speed vb (of inertial running) is
(Number 3)
ηcb­­ = (vc2 ^- vb2 ) ^{/ vc2}
Also, the average speed vcb during the coasting is
vcb≈(vc+vb)/2
becomes.
Therefore, if vc = 60 km/h and vb = 30 km/h, for example,
ηcb­­=0.75
vcb≈45km/h
can be
That is, by appropriately setting vc and vb, it is possible to keep both the kinetic energy utilization efficiency and the average speed during coasting within the permissible range in deceleration running due to coasting.

The basic concept of the present invention will be described below with reference to FIG.
In FIG. 3, a straight line P4-P6 indicates a braking deceleration straight line at the braking deceleration αb from the point P4 toward the point P6 of the constant speed running vehicle at the running speed vcmax.
That is, the vehicle that is traveling at a constant speed at the speed vcmax normally travels at a constant speed to the point P4, and then brakes from the point P4 toward the stop point P6 at the braking deceleration αb. As a result, the kinetic energy possessed by the vehicle at the speed vcmax is completely consumed during braking travel between points P4 and P6, and the effect of utilization of the kinetic energy of the vehicle for vehicle travel during this period, that is, the traveling distance is the point P4-P6 only the distance between them.
On the other hand, in the energy-saving deceleration running according to the present invention, the vehicle running within the inertial running transition allowable speed range, that is, the range of speeds vcmin to vcmax, starts normal running (acceleration (driving or constant speed) to coasting (for deceleration).
Further, after shifting to coasting, the upstream distance of point P6 on straight line P4-P6 where the coasting at speed v shifts to braking is
(Number 5)
d=v2 ^/ (2·αb)
becomes.

As shown in Fig. 3, the vehicle that coasts after passing point P3 within the range of speeds vcmin to vcmax that can transition to inertia travels. Constant speed running is performed until reaching the braking start straight line P4-P6, after which the vehicle reaches the target deceleration/stop point P6 by braking running at the braking deceleration αb.
Here, the point P45 is the point at which the inertial running transition possible speed upper limit vcmax reaches the initial braking start straight line P4-P6 of the inertial running. =v ² /(2·αb) is the braking distance.
The distance between the point P5 and the point P6 is the braking travel distance from the speed vcmin to the speed 0, that is, db= vcmin ² /(2·αb) .
Further, the vehicle passing the point P3 at a speed less than vcmin continues to run at a constant speed while maintaining the speed at which it passed the point P3 until it reaches the braking deceleration straight line P4-P6.

FIG. 4 shows the processing procedure in the energy-saving deceleration control method and its support device according to the present invention.
However, in this procedure example, after the vehicle intended to travel within a single unit travel section specifies the target deceleration/stop point, it shifts to deceleration travel based on inertia and stops at the target deceleration/stop point. It is limited to procedures.
In this procedure, it is assumed that the inertial traveling transferable speed range vcmin to vcmax, the inertial traveling start fixed distance dr upstream of the target deceleration stop point, and the braking deceleration αb are set and specified in advance.
Also, during this procedure, the vehicle speed and current vehicle position information shall be periodically identified in the background with the required frequency and accuracy.

In FIGS. 1 and 2, P1: Transmission acceleration start point P2: Acceleration end point, constant speed running start point P3: Inertia run start point P4: Low speed run end point, braking run start point P5: Inertia run end point, braking run Starting point P6: Target deceleration stop point, braking end point d11: Inertia travel distance d12: Acceleration travel distance d1: (Inertia travel + acceleration travel) travel distance during one cycle αa: Acceleration αb: Braking deceleration αi: Inertia travel decrease In velocity diagrams 3, 4, and (Equation 1) to (Equation 5)
P3: Inertia start point between vehicle speed vcmax and vcmin
P34: Coasting start speed vc3 Vehicle coasting end/constant speed starting point
P4: Braking start point from vehicle running speed vcmax
P45: Coasting start speed vc1 Vehicle coasting end /braking start point
P5: Inertia running end/brake running start point from inertia running start speed vc2 : Braking running start point from vehicle running speed vcmin
P6: Target deceleration/stop point ηcb: Kinetic energy utilization efficiency due to inertia v: Vehicle running speed (including low-speed coasting and braking)
vc: Inertia transition (start) speed vc1, vcmax: Inertia transition permissible (possible) upper limit speed vc2, vc3: Inertia transition permissible (possible) speed vc4, vcmin: Inertia transition permissible (possible) lower limit speed vb: Braking Running start speed vcb: Average speed during inertia running αi: Inertia running deceleration αb: Braking deceleration d: Distance between current point and target deceleration/stop point dr: Inertia running start constant distance upstream of target deceleration/stop point db: Braking start distance upstream of target deceleration/stop point dbmax = vcmax ² / (2 · αb): Braking travel distance from speed vcmax dbmin = vcmin ² / (2 · αb): Braking travel distance from speed vcmin

Claims (1)

A constant distance dr within the range of possible coasting distance at the upper limit speed (vcmax) of the speed range capable of coasting transition upstream of the target deceleration/stop point in a vehicle running within the speed range capable of coasting transition (vcmin to vcmax). starting coasting from a point, shifting from inertia running to braking running at a braking-run transition point with a distance db=v ² /(2·αb) upstream of the target deceleration/stop point, and reaching the target deceleration/stop point;
However, at the time point/point when the speed during inertial running reaches the lower limit speed vcmin of the speed range where inertial running can be shifted, the remaining distance d to the target deceleration/stop point is
If d>{vcmin ² /(2・αb)}, run at a constant speed v=vcmin until the remaining distance d reaches d={vcmin ² /(2・αb)}, or If the vehicle speed v after shifting to inertia running at the speed vc within the inertial running transitionable speed range is greater than or equal to the speed vc, until the remaining distance d reaches d = {vc ² / (2 · αb)} is an energy-saving deceleration running control method, characterized in that the vehicle moves from coasting to normal running while maintaining a speed vc.
where αb: Braking deceleration
v: Vehicle speed after coasting transition, where vcmin ≤ v ≤ vcmax
is.

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