KR20160109605A - Cruise Control System Implementing Eco-Drive Function Realizing Fuel Efficiency Enhancement In Downhill Section - Google Patents

Abstract

Disclosed is a cruise control system capable of automatically performing the fuel cut-off inertial driving of a vehicle from a starting point of a downhill section instead of the steady-speed driving of the vehicle when the vehicle drives in the downhill section, automatically re-accelerating the vehicle at a re-acceleration speed (a_re-acceleration), which is a constant preset in a memory from a re-acceleration starting speed (V_2) determined according to procedure set in the below before the downhill section ends, driving the vehicle at a speed identical to a reference speed (V_1) when the downhill section starts at a location where the downhill section ends, and thereafter driving the vehicle at a steady speed. The cruise control system of the present invention is capable of performing an eco-drive function of an optimal driving pattern in the downhill section, instead of driving the vehicle at the steady speed, thereby being economical by optimally improving the fuel efficiency of the vehicle.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a cruise control system, and more particularly to a cruise control system that realizes fuel efficiency improvement by fuel cut-

[0001] The present invention relates to a constant-speed-cruise control device installed in a vehicle, and more particularly, to a cruise control system for a vehicle that automatically performs fuel cutoff inertia travel from a starting point of a downhill section instead of a constant- The engine starts to re-start automatically before the end of the section, and at the point where the downhill section ends, the engine speed becomes equal to the engine speed at the beginning of the downhill section. Thereafter, the engine continues to run at constant speed to achieve the optimum fuel economy in the downhill section Speed running control device in which an eco-drive function for performing an optimum running pattern is implemented.

The cruise control system installed in the vehicle implements the function of maintaining the speed set by the driver. According to such a constant-speed-cruise control device, the driver does not have to step on the accelerator pedal, thereby reducing the fatigue of the operation and improving the convenience of operation. On the other hand, when the driver presses the accelerator or the brake pedal, the constant-speed driving mode is released.

Although such a constant-speed-cruise control device improves the convenience of operation, safety problems may occur if the vehicle always travels at a constant speed regardless of the operating environment. For example, there is a possibility of a vehicle collision when another vehicle is running at a slow speed in front of the vehicle. In order to solve such a problem, a method of detecting the presence of an obstacle in the front and lowering the speed when there is an obstacle ahead and performing the constant speed running function at a set speed only when there is no obstacle ahead is adopted. An example of this can be found in Patent Application No. 1998-036324 (published on Aug. 05, 1998).

Also, the cruise control device that runs only at the set speed may interfere with the implementation of economical operation. In order to solve such a problem, an eco-drive function is partly employed in the constant-speed-cruise control device. These examples include patent registration No. 10-0308970 (registered on September 03, 2001), patent registration No. 10-0435662 (registered on June 26, 2004), patent registration No. 10-1168744 (2012. 07. 19 ), And Patent Registration No. 10-1241783 (registered on March 3, 2013).

In the above-mentioned prior art, it is rather advantageous for the economical driving that the constant-speed running is not performed according to the gradient of the road in the inclined section, that is, the uphill section and the downhill section in the constant- Driving, that is, fuel economy improvement operation. However, the constant-speed-cruise control device may be further improved for fuel efficiency improvement.

Accordingly, an object of the present invention is to provide a constant-speed-cruise control device capable of achieving fuel economy improvement operation in a downhill section.

More specifically, it is an object of the present invention to automatically perform a fuel cut-off inertia running from the starting point of a downhill section instead of a constant-speed run when the vehicle is running on a downhill section, An eco-drive function that allows the vehicle to perform the optimum driving pattern that achieves the optimum fuel economy in the downhill section by causing the speed to be the same as the speed at the beginning of the downhill section at the end of the downhill section, And to provide a constant-speed-cruise control device.

In order to achieve the above-mentioned object, the constant-speed-cruise control system implementing the eco-drive function for realizing the improvement of the fuel economy by the fuel cutoff inertial travel in the downhill section according to the present invention includes a control unit for controlling the constant- And a memory unit for storing application programs and data and for storing data generated by the process of the control unit.

The control unit may cause the vehicle to automatically perform the fuel cutoff inertial running from the starting point of the downhill section instead of the constant speed running when the vehicle is running on the downhill section and then perform the fuel cutoff inertial run automatically after the downhill section is completed, equal to the speed (V ₂₎ the reference speed (V ₁₎ at the time automatically in starting the inside material as constant material speed (a _{material in)} pre-set to the memory point is the downhill section end is the downhill section starting from Speed, and then continues the constant-speed travel,

The control unit calculating a running resistance (F) for the speed (V _1), that is the reference velocity (V ₁₎ of the vehicle at the start of the downhill section;

Temporarily setting a recirculation start speed (V ₂ ) at which the fuel shutdown inertial travel is stopped and the re-acceleration is started in the downward section;

Running resistance (F) = chajung (W) x deceleration (a _{pew eolkeot)} ... ... ... ... ... (One)

Calculating a deceleration (a _{fuel cut} ) according to the above formula (1);

V = V ₁ - Σ (a _{pew eolkeot} x Δt) ... ... ... ... ... (2)

Calculating a velocity (V) profile of the vehicle during fuel cut inertia traveling until V = V _{2 according} to equation (2);

s _{Fuel Cut} = Σ (V x Δt) _{Fuel Cut} ... ... ... ... ... (3)

Calculating the expression (3) Pugh eolkeot total distance (s _{Pew eolkeot)} traveled while the vehicle is in the fuel cut traveling by inertia;

V ₁ - V ₂ = a _ashes x t _ashes ... ... ... ... (4)

(4), the time taken until the vehicle accelerates to a reference speed (V ₁ ) accelerated to a preset reference speed (a _{rest speed} ), which is a preset constant in the memory, after the vehicle ends the fuel cutoff inertial running Δt _{re-acceleration} );

s _{re-acceleration} = V _{re-acceleration average velocity} x Δt _{Re-acceleration} ... ... ... ... ... (5)

(Wherein, V _{material in an average rate = (V 1 + V 2)} / 2 Im)

(5), the reburn total running distance (s _rebound ) running until the vehicle accelerates to the reference speed (V ₁ ) after the completion of the fuel cut inertia running is accelerated to the ash speed (a _{rest speed} ) Calculating;

The downhill from the starting point of the interval distance to the end point of the downhill section, that is, the total distance the fuser eolkeot the length (s) of the downhill section (s _{Pew eolkeot)} and the total distance traveled in the material (s _{material inside)} And determining whether or not they coincide with each other;

The length (s) for which the fuser eolkeot total distance (s _{Pew eolkeot)} and if it matches the sum of the material in the total running distance (s _{material inside),} beginning in the material is set to the tentative speed (V ₂₎ Establishing definitively;

Decreasing the length (s) that the fuser eolkeot total distance (s _{Pew eolkeot)} and if the material is in greater than the sum of the total distance (s _{material inside),} beginning in the material is set to the tentative speed (V ₂₎ And then repeating the above steps. And

The length (s) that the fuser eolkeot total distance (s _{Pew eolkeot)} with the ashes in the case is less than the sum of the total distance (s _{material inside),} increase a material in the starting velocity (V ₂₎ set to the tentative And then repeating the above steps.

Wherein data necessary for calculating the driving resistance force (F) is that the engine speed of the vehicle is received from the control device of the vehicle, and the speed of the vehicle is from a control device of the vehicle or a navigation device And the position information of the vehicle and the inclination and length of the downhill section may be received from the navigation apparatus.

Driving resistance (F) = rolling friction resistance + air resistance - gradient resistance + internal resistance ... ... ... ... ... (1-1)

Rolling friction resistance = Rolling resistance coefficient x Car weight x Gravity acceleration ... ... ... ... ... (1-2)

Air resistance = air resistance coefficient x speed ² ... ... ... ... ... (1-3)

Gradient Resistance = Vehicle Weight x Gravity Acceleration x sin θ ... ... ... ... ... (1-4)

(Where, &thetas; is the inclination angle of the downward section)

Internal resistance = Internal resistance factor x Engine speed ... ... ... ... ... (1-5)

(Where the various coefficients in the above equations are determined from measurements taken from vehicle experiments)

The running resistance F is preferably calculated by the above equations at the beginning of the downhill section.

According to the constant-speed-cruise control device of the present invention, since the eco-drive function of the optimum travel pattern is implemented instead of the constant-speed cruising in the downward section, the fuel economy of the vehicle is optimally improved and economical.

1 is a diagram showing a schematic configuration of a constant-speed-cruise control device according to the present invention.
FIGS. 2 to 4 are flowcharts of a procedure in which the control unit performs an eco-drive function in a downhill section in the constant-speed-cruise control apparatus of the present invention.
5 is a graph showing the fuel consumption rate and the fuel consumption obtained in an experiment in which the vehicle travels without fuel cutoff inertia travel in a downward section.
FIG. 6 is a graph showing the fuel consumption rate and the fuel consumption obtained in the experiment in which the fuel cutoff inertia travel and the reacceleration are performed in the downward section.
FIG. 7 is a view for explaining a situation in which simulation is performed to verify that a fuel cut-off inertia running after a downhill section according to the present invention is a method for achieving an optimum fuel consumption in a rebuilt running.
8 is a table showing calculation results according to the simulation of FIG.
9 is a graph showing a calculation result according to the simulation of FIG.
10 is a table showing other calculation results according to the simulation of FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1, the constant-speed-cruise control system 10 of the present invention includes a control unit 100 and a memory unit 200. [ In addition, the cruise control device 10 of the present invention may include an input unit 300, an input port 400, and an output unit 500.

The control unit 100 performs the procedure described below in detail in the constant-speed-cruise control system 10 of the present invention so as to achieve the optimum fuel economy in the downhill section. That is, when the vehicle travels on a downhill section, the controller 100 automatically performs a fuel cutoff inertial travel from the starting point of the downhill section instead of the constant-speed travel, and then, before the downhill section is completed, (A _{re-acceleration} ), which is a constant preset in the memory, at the re-acceleration starting speed V ₂ , and at the point where the downward motion section ends, the reference speed V ₁ ), and then continues the constant-speed travel.

The memory unit 200 stores application programs and data necessary for the processing of the control unit 100 and also stores data generated by the processing of the control unit 100. [

The input unit 300 inputs the setting of the driver. In the present invention, in order to calculate the re-acceleration start speed in the downward section, the running resistance F of the vehicle must be calculated first. The running resistance F of the vehicle can be calculated by knowing data on the speed of the vehicle, the weight of the vehicle, i.e., the vehicle weight W, the road gradient of the downhill section, the engine speed, have. Accordingly, the driver inputs the type of the vehicle he / she owns by using the input unit 300, so that the control unit 100 sets data concerning the various types of vehicles and various resistance coefficients and stores them in the memory unit 200.

On the other hand, the constant-cruise control device 10 of the present invention can receive the engine speed of the vehicle from the control unit (ECU) of the vehicle, and may include an input port 400 for this purpose. The cruise control device of the present invention may also receive the road gradient from a navigation device attached to the vehicle, and may be provided with an input port 400 for this purpose. The cruise control device of the present invention should receive data on the speed of the vehicle, the position information of the vehicle, and the length of the downhill section in order to perform the functions described below. The speed of the vehicle can be received from the control device or the navigation device of the vehicle, and the position information of the vehicle and the inclination and length of the downward section can be received from the navigation device.

The output unit 500 may be adapted to issue a current driving state of the vehicle to the driver in accordance with an instruction from the control unit 100. [ There are a visual method of outputting the notification to the driver to the screen and an auditory method of outputting to the speaker, either of which may be used or both of them may be used. Accordingly, the output unit 500 may be a display device or a speaker. The output unit 500 may be implemented in such a manner that the eco-drive lamp is turned on so that the driver can recognize such a situation, for example, when the eco-drive function according to the present invention is performed in the downhill section of the vehicle.

Now, with reference to FIG. 2 to FIG. 4, a description will be given of a procedure in which the controller 100 performs the eco-drive function in the constant cruise control system 10 of the present invention. Since the procedure for the control unit 100 to perform the constant speed running function in the constant speed running control apparatus 10 of the present invention is generally well known, the description of the constant speed running function will be omitted here.

As shown in the figure, the control unit 100 first determines whether the vehicle is at the starting point of a downhill section (step S100). If the vehicle has not reached the downhill section, the control section 100 performs the constant-speed running function only and continuously determines the situation until the vehicle enters the downhill section without performing any other special operation.

If the vehicle has entered the starting point of the downhill section, the control section 100 instructs the start of the fuel cut inertial travel (step S110). Then, the fuel injection device stops the fuel injection in accordance with the instruction of the control section 100 to start the fuel cutoff inertia running.

Next, the controller 100 calculates the running resistance (F) for the reference speed (V ₁₎ of the vehicle (step S120). Here, the reference speed V ₁ of the vehicle means the speed of the vehicle when the vehicle enters the starting point of the downward section.

The running resistance (F) is calculated by the following equation.

Driving resistance (F) = rolling friction resistance + air resistance - gradient resistance + internal resistance ... ... ... ... ... (1-1)

In the equation (1-1), the rolling resistance of the tire represents the rolling resistance between the tire and the road surface. The air resistance shows the resistance by the air. The gradient resistance is the resistance by the road gradient. And the like. Therefore, the gradient resistance is negative (-) in contrast to other resistances in the downward section. The internal resistance is proportional to the number of revolutions of the engine due to the resistance due to the friction loss of various types of gears and type (air conditioner, generator, coolant pump, etc.) connected to the tire and the engine. These resistances are calculated by the following equations.

Rolling friction resistance = Rolling resistance coefficient x Car weight x Gravity acceleration ... ... ... ... ... (1-2)

Air resistance = air resistance coefficient x speed ² ... ... ... ... ... (1-3)

Gradient Resistance = Vehicle Weight x Gravity Acceleration x sin θ ... ... ... ... ... (1-4)

(Where, &thetas; is the inclination angle of the downward section)

Internal resistance = Internal resistance factor x Engine speed ... ... ... ... ... (1-5)

(Where the various coefficients in the above equations are determined from measurements taken from vehicle experiments)

Next, the controller 100 temporarily sets the starting material in the speed (V ₂₎ to stop the fuel cut inertia traveling downhill section starting in the material (step S130). At this time, when the material is in the starting velocity (V ₂₎ to temporarily set to the difference between large and the final material is in the starting velocity (V ₂₎ for deciding a is so large that the number of repeating the procedure described below, as much as possible and finally confirmed by Is set to be close to the re-acceleration start speed (V ₂ ). For this purpose, the constant-speed-cruise control system of the present invention can confirm the relation between the inclination and the length of the downhill road and the reacceleration start speed (V ₂ ) with respect to the speed of the vehicle through the sufficient experiment for the eco-drive function. With such a relation, in starting material that temporarily set to a speed (V ₂₎ will be able to be set closer to the ultimate starting materials are confirmed in the speed (V _2).

Next, the controller 100 is the degree to which the vehicle reference speed (V ₁₎ of the vehicle by the running resistance (F) calculated on when starting the fuel cut inertia running speed is reduced in the downhill section, that deceleration ( a _{fuel cut} ) is calculated by the following equation (1) (step S140).

Running resistance (F) = chajung (W) x deceleration (a _{pew eolkeot)} ... ... ... ... ... (One)

Then, the control unit 100 calculates the speed V profile of the vehicle by the following equation (2) until the speed V of the vehicle during the fuel cutoff inertia travel becomes the re-acceleration start speed V ₂ Step S150). Here, the vehicle is subjected to the fuel cut-off inertia traveling from the reference speed (V ₁ ) to the re-acceleration start speed (V ₂ ).

V = V ₁ - Σ (a _{pew eolkeot} x Δt) ... ... ... ... ... (2)

Next, the control unit 100 the vehicle is the fuser eolkeot total distance (s _{Pew eolkeot)} traveled during the fuel-cut traveling inertia calculated by the following formula (3) (step S160).

s _{Fuel Cut} = Σ (V x Δt) _{Fuel Cut} ... ... ... ... ... (3)

Thereafter, the control unit 100 determines the time (t) from the completion of the fuel cut-off inertia running until the vehicle accelerates from the re-acceleration start speed V ₂ to the ash accumulation speed (a _{reacceleration} ) to become the reference speed V ₁ and it calculates the _{ash in)} by the following formula (4) (step S170). Here, the ash reacceleration rate (a _{reacceleration} ) is previously set and stored in the memory unit 200 as a constant. The ash rate (a _{reacceleration} ) can be set to, for example, 0.5 m / s ² .

V ₁ - V ₂ = a _ashes x t _ashes ... ... ... ... (4)

Next, the control unit 100 the vehicle fuel cut inertia driving and exit material speed (a _{material in)} in a driving material into a total travel until the acceleration and the reference velocity (V _1), the distance (s _{material inside),} and then (5) (step S180).

s _{re-acceleration} = V _{re-acceleration average velocity} x Δt _{Re-acceleration} ... ... ... ... ... (5)

(Wherein, V _{material in an average rate = (V 1 + V 2)} / 2 Im)

Then, the control unit 100 are the distance to the end point of the downhill section from the start of the downhill section, that is, the total distance the length (s) of the downhill section Pew eolkeot (s _{Pew eolkeot)} and the total distance in material (s _{(I.e., re-acceleration} ), and judges whether or not they coincide with each other (step S190). Here, the distance s from the start point of the downhill section to the end point of the downhill section is set to the length of the downhill section received from the navigation apparatus mounted on the vehicle. Since the control unit 100 receives the position of the vehicle from the navigation device mounted on the vehicle in real time, it can instruct the start of the fuel cutoff inertial travel when the vehicle enters the starting point of the downhill section.

Distance to the downhill end point of the interval from the start of the downhill section, i.e., that the length (s) of the downhill section matches the sum of the fuser eolkeot total distance (s _{Pew eolkeot)} and the material in the total running distance (s _{material inside)} case, the definite set to the temporary starting material in a set speed (V ₂₎ (step S200).

Then the control unit 100 determines (step S210), In such a case, the controller 100 whether the speed (V) of the vehicle reaches the starting speed in material (V ₂₎ is in a predetermined material speed (a _{material in)} And instructs the vehicle to accelerate (step S220). Then, in accordance with such an instruction of the control unit 100, the engine output is increased, and the vehicle speed is increased. On the other hand, when the vehicle speed V does not reach the re-acceleration start speed V ₂ , the fuel cut inertia continues to be continued.

The controller 100 determines whether the current speed V of the vehicle has reached the reference speed V ₁ , that is, whether the current speed V of the vehicle is equal to the reference speed V ₁ (Step S222). In such a case, it is determined that the vehicle has reached the end point of the downhill section, the re-acceleration is terminated and the constant speed is maintained (step S224). Thus, the eco-drive function in the downward section is terminated. On the other hand, if the current speed V of the vehicle has not reached the reference speed V ₁ , the re-acceleration of the vehicle continues.

On the other hand, greater than the sum of the distance from the start of the downhill section to the end point in the downhill section, that total travel length (s) the fuser eolkeot the downhill section distance (s _{Pew eolkeot)} and the total distance in material (s _{material inside)} If larger (step S230), reduces the temporary material into a starting speed (V ₂₎ set after reset (step S240) the procedure goes back to step S130 and repeats the above process.

On the other hand, distance to the downhill end point of the interval from the start of the downhill section, that is the sum of the length (s) of the downhill section is Pew eolkeot total distance (s _{Pew eolkeot)} and the total distance in material (s _{material inside)} If smaller (step S230), then by increasing the temporary material into a starting speed (V ₂₎ set to the reset (step S260) the procedure goes back to step S130 to repeat the process.

Degree of reduction or increase for temporarily reset to the material in the starting velocity (V ₂₎ in the extent of the length (s) and Pugh eolkeot total distance (s _{Pew eolkeot)} and the material in the total running distance (s _{material inside)} The number of iterations can be reduced by selecting an appropriate value according to the degree of the sum difference.

Experiments and simulations as shown in FIGS. 5 to 10 have been performed in order to show that the method according to the present invention realizes the optimum fuel consumption in the downward section.

First, in the case where the fuel cutoff inertial travel is not used in the downhill section of the similar road and driving condition, and when the rearward running after the fuel cutoff inertial travel according to the present invention is performed, the fuel cost is about The difference of 3 to 4 times was confirmed by FIGS. 5 and 6.

Referring to FIG. 5, the fuel consumption was 15.2 km / L when the travel distance was 800 m at an average speed of 69.7 km / h in a downhill section having an inclination of 0.72 degrees without fuel cutoff inertial travel. On the other hand, referring to FIG. 6, The average mileage was 66.7 km / h, and the mileage was 800 km, the fuel consumption was 51.6 km / L when the vehicle was driven in the manner of the fuel cutoff inertia according to the present invention.

Next, as shown in Fig. 7, a downhill section having an inclination of 20 km, 40 m and 60 m in height, with a horizontal distance of 2 km and running at a speed of 110 km / h 1 km before the downhill section, Simulation of the situation that the original reference speed is returned to 110 km / h with the acceleration of 0.5 m / s ² at 95 km / h, 90 km / h and 85 km / h, Was set and calculated using the fuel consumption simulation software CRUISE program.

Referring to FIGS. 8 and 9, when the vehicle is rebuilt at a speed of 100 km / h, 95 km / h, 90 km / h and 85 km / h at a road gradient of 10 m / km and 20 m / km, The distance (the distance required to reach the original reference speed of 110 km / h) was shorter than that of the downhill section, and the longer the fuel cutoff inertia distance was, the better the fuel economy was. Here, the road gradient is expressed as height / horizontal distance. On the other hand, in the case of re-acceleration at a speed of 100 km / h at a road gradient of 30 m / km, the sum of the fuel cutoff inertia travel distance and the rebound distance is shorter than that of the downhill section. However, The sum of the inertia travel distance and the ash travel distance was slightly longer than the distance of the downhill section, and the sum of the fuel blocking inertia travel distance and the ash travel distance was longer than the downhill section distance when the vehicle was rebounding at 90 km / h and 85 km / h . As a result, the best fuel economy was obtained when the vehicle was rebounding at a speed of 95 km / h. In FIG. 8, the fuel consumption amount is the fuel consumption amount in the driving range, and the fuel consumption is fuel consumption with respect to the sum of the fuel cutoff inertia travel distance and the re-feed distance.

More sophisticated simulation results are shown in Fig. Referring to FIG. 10, when the road is decelerated at a speed of 68.6 km / h in a downward section of 10 m / km, and when the speed is reduced at a speed of 82 km / h in a downward section of a road gradient of 20 m / And the recirculation distance becomes equal to the distance of the downward section, and the fuel economy becomes highest at 26.4km / L and 42.1km / L, respectively.

On the other hand, if the vehicle is re-accelerating at a speed of 95.3 km / h in a downhill section of a road gradient of 30 m / km, the sum of the fuel-blocking inertia travel distance and the rebound distance becomes equal to the distance of the downhill section, It becomes the best. If the fuel cutoff inertia travels further and starts to accelerate at a speed of 95 km / h, the sum of the fuel cutoff inertia travel distance and the recoil distance becomes greater than the downhill distance. This means that when the original speed is 110 km / h, it is in the flat section after the end point of the downward section. 10 shows that the fuel efficiency is 68.1 km / L, which is less than the optimum fuel efficiency (75.5 km / L) when the speed of starting the re-acceleration is 95 km / h.

10: Constant speed drive control device 100:
200: memory unit 300: input unit
400: Input port 500: Output section

Claims (3)

And a memory unit for storing application programs and data necessary for the processing of the control unit and for storing data generated by the processing of the control unit,
The control unit may cause the vehicle to automatically perform the fuel cutoff inertial running from the starting point of the downhill section instead of the constant speed running when the vehicle is running on the downhill section and then perform the fuel cutoff inertial run automatically after the downhill section is completed, equal to the speed (V ₂₎ the reference speed (V ₁₎ at the time automatically in starting the inside material as constant material speed (a _{material in)} pre-set to the memory point is the downhill section end is the downhill section starting from Speed, and then continues the constant-speed travel,
The control unit calculating a running resistance (F) for the speed (V _1), that is the reference velocity (V ₁₎ of the vehicle at the start of the downhill section;
Temporarily setting a recirculation start speed (V ₂ ) at which the fuel shutdown inertial travel is stopped and the re-acceleration is started in the downward section;
Running resistance (F) = chajung (W) x deceleration (a _{pew eolkeot)} ... ... ... ... ... (One)
Calculating a deceleration (a _{fuel cut} ) according to the above formula (1);
V = V ₁ - Σ (a _{pew eolkeot} x Δt) ... ... ... ... ... (2)
Calculating a velocity (V) profile of the vehicle during fuel cut inertia traveling until V = V _{2 according} to equation (2);
s _{Fuel Cut} = Σ (V x Δt) _{Fuel Cut} ... ... ... ... ... (3)
Calculating the expression (3) Pugh eolkeot total distance (s _{Pew eolkeot)} traveled while the vehicle is in the fuel cut traveling by inertia;
V ₁ - V ₂ = a _ashes x t _ashes ... ... ... ... (4)
(4), the time taken until the vehicle accelerates to a reference speed (V ₁ ) accelerated to a preset reference speed (a _{rest speed} ), which is a preset constant in the memory, after the vehicle ends the fuel cutoff inertial running Δt _{re-acceleration} );
s _{re-acceleration} = V _{re-acceleration average velocity} x Δt _{Re-acceleration} ... ... ... ... ... (5)
(Wherein, V _{material in an average rate = (V 1 + V 2)} / 2 Im)
To, after the vehicle fuel cut inertia driving end ash rate (a _{material in)} in a driving material into a total travel until the acceleration and the reference velocity (V _1), the distance (s _{material inside)} by the formula (5) Calculating;
The downhill from the starting point of the interval distance to the end point of the downhill section, that is, the total distance the fuser eolkeot the length (s) of the downhill section (s _{Pew eolkeot)} and the total distance traveled in the material (s _{material inside)} And determining whether or not they coincide with each other;
The length (s) for which the fuser eolkeot total distance (s _{Pew eolkeot)} and if it matches the sum of the material in the total running distance (s _{material inside),} beginning in the material is set to the tentative speed (V ₂₎ Establishing definitively;
Decreasing the length (s) that the fuser eolkeot total distance (s _{Pew eolkeot)} and if the material is in greater than the sum of the total distance (s _{material inside),} beginning in the material is set to the tentative speed (V ₂₎ And then repeating the above steps. And
The length (s) that the fuser eolkeot total distance (s _{Pew eolkeot)} with the ashes in the case is less than the sum of the total distance (s _{material inside),} increase a material in the starting velocity (V ₂₎ set to the tentative And then repeating the above-described steps after resetting the engine speed. The eco-drive function realizes the fuel economy improvement by the fuel cutoff inertia running in the downhill section. The method according to claim 1,
Wherein data necessary for calculating the driving resistance force (F) is that the engine speed of the vehicle is received from the control device of the vehicle, and the speed of the vehicle is from a control device of the vehicle or a navigation device Wherein the vehicle position information and the inclination and length of the downhill section are received from the navigation device. The eighth aspect of the present invention is the vehicle navigation system according to the first aspect of the present invention, A drive control device; 3. The method according to claim 1 or 2,
Driving resistance (F) = rolling friction resistance + air resistance - gradient resistance + internal resistance ... ... ... ... ... (1-1)
Rolling friction resistance = Rolling resistance coefficient x Car weight x Gravity acceleration ... ... ... ... ... (1-2)
Air resistance = air resistance coefficient x speed ² ... ... ... ... ... (1-3)
Gradient Resistance = Vehicle Weight x Gravity Acceleration x sin θ ... ... ... ... ... (1-4)
(Where, &thetas; is the inclination angle of the downward section)
Internal resistance = Internal resistance factor x Engine speed ... ... ... ... ... (1-5)
(Where the various coefficients in the above equations are determined from measurements taken from vehicle experiments)
Wherein the driving resistance force (F) is calculated by the above equations at the beginning of the downhill section. An eco-drive control device for realizing an eco-drive function for improving fuel economy by fuel cut inertia running in a downhill section.

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