JP2012111320A - Auto-cruise controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auto-cruise controller that can fuel-efficiently and economically cruise travel through traveling at the lowermost number of engine revolutions in the situation where no high acceleration performance is needed.SOLUTION: When an inter-vehicle gap control during auto-cruise traveling is made (S1), a vehicle load, an engine output, and the number of engine revolutions after an upshift (S2, S4 and S5) are determined, and an upshift is executed in a preceding vehicle following where no high acceleration is needed (S6).

Description

  The present invention relates to an auto-cruise control device, and in particular, while traveling automatically at an arbitrary speed specified by the driver, when there is a preceding vehicle, the inter-vehicle distance control with the preceding vehicle is performed, The present invention relates to shift control during inter-vehicle distance control.

In recent years, for the purpose of reducing the burden on the driver and the like, a vehicle having an auto-cruise function and the like for traveling at an arbitrary speed designated by the driver has been developed.
As for the shift control of the transmission during such an auto-cruise traveling, conventionally, the shift-up is performed based on the vehicle speed, and the shift-down is performed based on the throttle opening, the engine speed, and the acceleration.

  In addition, a shift indicator device has been developed for instructing the driver to shift comfortably on an uphill road or the like and improving fuel efficiency and acceleration, or improving practicality (see Patent Document 1). ). In the shift indicator device, the running resistance is calculated, the acceleration after the upshift is calculated based on the running resistance, and the shift is performed when the acceleration after the upshift is a target acceleration corresponding to the vehicle speed and the accelerator opening. It is determined that the up instruction condition is satisfied, and a shift up display is performed.

JP 2009-97670 A

However, if there is a preceding vehicle traveling at a speed lower than the speed specified by the driver during auto-cruise traveling, the speed of the host vehicle is reduced to avoid a collision with the preceding vehicle. It is necessary to carry out inter-vehicle distance control to keep the distance between vehicles.
The technique disclosed in Patent Document 1 does not have such an inter-vehicle distance control function, and does not consider shift control during inter-vehicle distance control. According to conventional shift control, if the vehicle speed is reduced to ensure the distance from the preceding vehicle, the difference from the target vehicle speed specified by the driver widens. The rotation speed becomes high. However, it is not necessary to maintain a high acceleration performance while following the preceding vehicle, and if the vehicle continues to run at such a high engine speed, the fuel consumption deteriorates and it is uneconomical.

  The present invention has been made to solve such problems, and the object of the present invention is to achieve low fuel consumption and economy by running at the lowest engine speed in situations where high acceleration performance is not required. Is to provide an automatic cruise control device capable of performing a typical cruise traveling.

  In order to achieve the above object, in the auto cruise control device according to claim 1, in the auto cruise control device for automatically running the vehicle, the drive force from the engine can be changed stepwise in the vehicle. Based on the acceleration detected by the acceleration detecting means, the inter-vehicle distance control means for controlling the inter-vehicle distance between the speed change means and the preceding vehicle traveling in front of the host vehicle, the acceleration detecting means for detecting the acceleration of the vehicle. Vehicle load degree calculating means for calculating the vehicle load degree for traveling, engine output detecting means for detecting the output of the engine, and engine speed when the gear position of the speed change means is changed to the low gear ratio side. The vehicle load degree calculated by the vehicle load degree calculation means during execution of the inter-vehicle distance control by the post-shift engine speed calculation means and the inter-vehicle distance control means is calculated. At least the vehicle speed set by the inter-vehicle distance control is less than or equal to a predetermined vehicle load degree threshold that can realize the vehicle speed, and the engine output detected by the engine output detecting means can realize at least the vehicle speed set by the inter-vehicle distance control The engine speed after the shift calculated by the engine speed calculation means after the shift is less than or equal to a predetermined engine output threshold, and at least equal to or greater than a predetermined engine speed threshold that can realize the vehicle speed set by the inter-vehicle distance control. Shift control means for changing the gear position of the speed change means to the low gear ratio side in some cases.

  According to a second aspect of the present invention, in the automatic cruise control device according to the first aspect, the vehicle load degree calculating means is calculated based on a difference between a vehicle acceleration under a reference condition and an acceleration detected by the acceleration detecting means. It is characterized by that.

  According to the auto-cruise control device of the present invention using the above means, the shift-up is performed at the time of execution of the inter-vehicle distance control during the auto-cruise traveling and following the preceding vehicle that does not require high acceleration. It is possible to run at a low engine speed. From this, it is possible to perform an economical cruise traveling with low fuel consumption.

In addition, the vehicle speed, engine output, and engine speed after upshifting are determined, and then the upshifting is performed, so that stable driving that achieves the vehicle speed of the inter-vehicle distance control is maintained even after the upshifting. be able to.
According to the auto-cruise control device of the second aspect, it is possible to determine that the uphill road or the vehicle is heavy only by the acceleration of the vehicle. Can be judged.

1 is a schematic configuration diagram showing an overall configuration in an embodiment of an auto cruise control device according to the present invention. It is the block diagram which showed the structure of auto-cruise ECU in one Embodiment of the auto-cruise control apparatus which concerns on this invention. It is a flowchart showing the upshift control routine which the shift control part of autocruise ECU in one embodiment of the autocruise control device concerning the present invention performs.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing the overall configuration of an embodiment of the present invention, and the configuration of the embodiment will be described with reference to FIG.
A vehicle 1 shown in FIG. 1 is a truck on which cargo can be loaded. The vehicle 1 is equipped with an engine 2 as a drive source, and a transmission 4 is connected to the engine 2. The engine 2 can adjust the engine output according to the throttle opening. The transmission 4 is a so-called mechanical automatic transmission (AMT) that can automatically perform gear selection in accordance with the engagement / disengagement of the clutch and the shift change regardless of the operation of the driver.

Each wheel of the vehicle 1 is provided with a brake 6 that applies a braking force.
Further, the vehicle 1 is provided with various sensors such as a millimeter wave radar 8, a vehicle speed sensor 10, and a shift position sensor 12.
The millimeter wave radar 8 is installed in the front part of the vehicle 1 and detects obstacles such as a preceding vehicle in front of the vehicle 1 using millimeter wave band radio waves. Measures relative distance and relative speed.

The vehicle speed sensor 10 detects the vehicle speed from the wheel speed of the vehicle 1.
The shift position sensor 12 detects a shift position selected by the driver's operation of the shift lever. As the shift position, for example, a drive range (D range) for performing automatic shifting, and a gear of the transmission is driven neutral. Neutral range (N range) that shuts off the force, Parking range (P range) that locks the gear of transmission 4, Reverse range (R range) that reverses, Second range (2nd range that manually selects the gear stage) ), First range (1st range), and the like.

  The vehicle 1 is equipped with various ECUs (electronic control units) such as an engine ECU 14, a brake ECU 16, a transmission ECU 18, an auto cruise ECU 20, and the like. These various ECUs 14, 16, 18, and 20 are configured to include an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), etc. Control is performed.

Specifically, the engine ECU 14 adjusts the throttle opening of the engine 2, the fuel injection amount, the injection timing, and the like, and controls engine driving force (engine torque), engine output, and the like.
The brake ECU 16 controls the braking force of the brake 6 of each wheel via an actuator (not shown).

In accordance with the shift position detected by the shift position sensor 12, the transmission ECU 18 connects and disconnects the clutch and selects the gear stage via an actuator (not shown) according to the driving state in the D range.
Further, the driver's seat of the vehicle 1 is provided with an auto-cruise operation unit 22 for switching ON / OFF of the auto-cruise function and setting an arbitrary target vehicle speed in the auto-cruise traveling, and the auto-cruise ECU 20 performs the auto-cruise operation. The automatic traveling control of the vehicle 1 is performed according to the setting in the unit 22.

Hereinafter, the configuration of the auto-cruise ECU 20 will be described in detail.
Referring now to FIG. 2, a block diagram conceptually showing the configuration of the auto-cruise ECU 20 is shown, which will be described below with reference to FIG.
As shown in FIG. 2, sensors such as the millimeter wave radar 8, the vehicle speed sensor 10, the shift position sensor 12, the engine ECU 14, and the like are connected to the input side of the auto-cruise ECU 20. Various information detected at is input. On the other hand, an engine ECU 14, a brake ECU 16, and a transmission ECU 18 are connected to the output side of the auto cruise ECU 20, and information is output to various ECUs based on the calculation results in the auto cruise ECU 20.

  Specifically, the setting information in the auto-cruise operation unit 22, the shift position information detected by the shift position sensor 12, and the vehicle speed information of the host vehicle detected by the vehicle speed sensor 10 are input to the auto-cruise control unit 30 of the auto-cruise ECU 20. Is done. In the auto-cruise control unit 30, the auto-cruise function is set to ON by the auto-cruise operation unit 22, and the target vehicle speed set by the auto-cruise operation unit 22 is satisfied when a predetermined condition is satisfied. It calculates the operating conditions such as engine output and braking force required for traveling. Here, the predetermined condition for performing auto-cruising is, for example, a state in which the shift position detected by the shift position sensor 12 is in the D range and the driver does not perform the accelerator operation and the brake operation.

And the calculation result in the said auto cruise control part 30 is input into the inter-vehicle distance control part 32 (inter-vehicle distance control means).
The driving distance calculated by the auto cruise control unit 30 is input to the inter-vehicle distance control unit 32, and the relative distance and relative speed with respect to the preceding vehicle detected by the millimeter wave radar 8 are input. In the inter-vehicle distance control unit 32, when there is a preceding vehicle during auto-cruise traveling, the target vehicle speed of auto-cruising is higher than that of the preceding vehicle, and the relative distance between the preceding vehicle and the host vehicle is shortened. The calculation is performed based on the driving conditions calculated in the auto cruise control unit 30 so as to follow the preceding vehicle while maintaining a predetermined inter-vehicle distance. For example, the inter-vehicle distance control unit 32 sets the vehicle speed of the own vehicle to the same speed as that of the preceding vehicle when the inter-vehicle distance with the preceding vehicle is kept constant, and increases the vehicle speed of the own vehicle when the inter-vehicle distance is increased. Set lower than the running car. Then, an instruction corresponding to the driving condition is output to the engine ECU 14, the brake ECU 16, and the transmission ECU 18 in order to perform driving under the driving condition of the calculation result.

  Further, the vehicle speed information detected by the vehicle speed sensor 10 is also input to the actual acceleration calculation unit 34 (acceleration detection means) of the auto cruise ECU 20. The actual acceleration calculation unit 34 calculates the actual acceleration of the host vehicle based on a change in the vehicle speed per unit time. The calculated actual acceleration is input to the vehicle load level calculation unit 36 (vehicle load level calculation means).

Engine torque information is also input from the engine ECU 14 to the vehicle load level calculation unit 36, and the vehicle load level is calculated using other specifications information of the vehicle 1 stored in advance.
Here, the vehicle load degree is a value indicating how much load is applied to the current vehicle 1 with respect to the standard, based on an empty state in which nothing is loaded on the vehicle 1 on a straight flat road. Specifically, it is calculated based on the difference between the acceleration in a straight flat road empty state (hereinafter referred to as ideal acceleration) and the actual acceleration. The ideal acceleration is basically calculated from the driving force of the vehicle 1 calculated from the engine torque and the power transmission efficiency of the driving system based on the equation of motion and the vehicle weight when the vehicle is empty. The vehicle load degree calculated in this way becomes higher as the actual acceleration becomes lower than the ideal acceleration and the difference becomes larger, for example, when traveling on an uphill road or when the vehicle weight is large. On the other hand, when the difference between the ideal acceleration and the actual acceleration is small, such as downhill, or when the actual acceleration is higher than the ideal acceleration, the vehicle load is a low value.

  Further, the auto-cruise ECU 20 includes a post-shift-up rotation speed calculation unit 38 (post-shift engine rotation speed calculation means), and the post-shift-up rotation speed calculation unit 38 includes vehicle speed information from the vehicle speed sensor 10 and a shift. The currently selected gear stage information from the machine ECU 18 is input. Then, the post-shift-up rotation speed calculation unit 38 calculates the engine speed after the shift-up based on the current vehicle speed and the gear ratio when the gear is shifted up one stage from the current gear stage.

  Further, the auto-cruise ECU 20 has a shift control unit 40 (shift control means). The shift control unit 40 calculates the vehicle load degree calculated by the vehicle load degree calculation unit 36 and the rotation speed after the upshift. The engine speed after the upshift calculated in the unit 38, the engine output information from the engine ECU 14, and the inter-vehicle distance control information from the inter-vehicle distance control unit 32 are input.

  The shift control unit 40 is set with a vehicle load level threshold value, a post-shift-up rotation speed threshold value, and an engine output threshold value corresponding to each of these pieces of input information, and each input during the inter-vehicle distance control. When the information is compared with the respective threshold values and it is determined that the vehicle can be driven at a low engine speed while realizing the vehicle speed based on the inter-vehicle distance control, the transmission ECU 18 is instructed to shift up the transmission 4.

Hereinafter, the upshift control executed in the shift control unit 40 will be described in detail.
FIG. 3 shows a flowchart showing a shift-up control routine during auto-cruise executed by the shift control unit 40 of the auto-cruise ECU 20, which will be described below with reference to FIG.

  As shown in step S <b> 1 of FIG. 3, the shift control unit 40 first determines from the information from the inter-vehicle distance control unit 32 whether the inter-vehicle distance control is being executed. In other words, the auto-cruise function is ON in the auto-cruise operation unit 22, the shift lever is set to the D range, and there is no accelerator or brake operation, and the auto-cruise is running. If it is, the determination result is true (Yes), and the process proceeds to the next step S2.

On the other hand, if the above conditions are not satisfied and the auto cruise is not performed, or if the auto cruise is performed and there is no preceding vehicle and the inter-vehicle distance control is not performed, the determination result is false (No ) And the routine returns. In this case, shift control by this function is not performed, and shift control based on auto cruise control, for example, similar to when the inter-vehicle distance control is OFF, is performed.
In step S2, it is determined whether or not the vehicle load degree calculated by the vehicle load degree calculation unit 36 is equal to or less than a vehicle load degree threshold value. The vehicle load degree threshold corresponds to the upper limit value of the vehicle load that can realize the vehicle speed set by the inter-vehicle distance control even after the upshift, and is set to be smaller as the gear stage of the transmission 4 is higher. Generally, the higher the gear stage, the lower the gear ratio and the smaller the acceleration generated with the same engine torque. The vehicle load level is the difference between the ideal acceleration and the actual acceleration, and the vehicle load level tends to decrease as the generated acceleration decreases, so the vehicle load level threshold is set to decrease as the gear stage increases. Has been.

Specifically, when traveling on an uphill road or the weight of the vehicle is heavy and the vehicle speed for inter-vehicle distance control cannot be realized if the vehicle is shifted up, the vehicle load level becomes larger than the vehicle load level threshold value, so the determination result is false. It becomes (No) and progresses to step S3.
In step S3, the transmission ECU 18 is not instructed to shift up to maintain the current gear position, and the routine returns.

On the other hand, in step S2, since the vehicle is traveling at a relatively low vehicle load level, such as following a preceding vehicle on a flat road, and the vehicle load level is less than the vehicle load level threshold, the determination result is true. (Yes), and proceeds to the next step S4.
In step S4, it is determined whether or not the engine output input from the engine ECU 14 is equal to or less than an engine output threshold value. The engine output threshold value corresponds to the upper limit value of the engine output capable of realizing the vehicle speed set by the inter-vehicle distance control even after the shift up, and the engine output from the substantially constant speed state to the slow acceleration state, for example, about 30% engine output. Is set to

  When the vehicle 1 is in an acceleration state and outputs a large engine output, and the engine output is greater than the engine output threshold, the determination result is false (No), the process proceeds to step S3, the gear stage is maintained, and the routine is performed. To return. On the other hand, if the engine speed is almost constant and the engine is slowly accelerating, the engine output is small and is equal to or smaller than the engine output threshold, the determination result is true (Yes), and the process proceeds to the next step S5.

  In step S5, it is determined whether or not the engine speed after upshifting calculated by the engine speed calculating unit 38 after upshifting is equal to or greater than a threshold value for the after-upshifting engine speed. The post-upshift speed threshold is the lower limit of the engine speed at which the vehicle speed set by the inter-vehicle distance control can be achieved even after the upshift, and the lower the gear stage, the higher the value to emphasize acceleration. The higher the value is, the lower the value is so as to emphasize the economy. For example, the post-upshift speed threshold is set to a value that does not cause at least an engine stall due to a decrease in the engine speed after the upshift.

  Accordingly, when the calculated engine speed after the upshift is low and is smaller than the threshold value after the upshift, the determination result is false (No), the process proceeds to step S3, the gear stage is maintained, and the routine is performed. To return. On the other hand, if the calculated engine speed after the shift-up is equal to or greater than the threshold value after the shift-up and the necessary speed can be secured, the determination result is true (Yes), and the process proceeds to the next step S6. .

In step S6, the transmission ECU 18 is instructed to execute upshifting, and the routine is returned.
In this way, the control routine as described above is repeated when the inter-vehicle distance control is executed during auto-cruise traveling, and the up-shifting is performed when following the preceding vehicle that does not require high acceleration, so that traveling at the lowest engine speed is possible. Done. From this, the vehicle 1 can perform economical cruise traveling with low fuel consumption.

In addition, after the upshifting, the shift up is performed after determining the vehicle load level, the engine output, and the engine speed after the upshift using the threshold values as in steps S2, S4, and S5 above. In addition, it is possible to maintain a stable running that achieves the vehicle speed of the inter-vehicle distance control.
In particular, in the determination of the vehicle load level in step S2, it is possible to determine that the uphill road or the vehicle is heavy only by the acceleration of the vehicle. Can be judged.

In addition, about said step S2, S4, it is preferable to set predetermined determination time and to set a determination result to be true (Yes) when a condition is satisfied during the predetermined determination time. As a result, it is possible to prevent inadvertent shift up due to a temporary decrease in vehicle load or a temporary decrease in engine output.
Although the description of the embodiment of the auto cruise control device according to the present invention has been completed above, the embodiment is not limited to the above embodiment.

  For example, in the above embodiment, the auto-cruise control condition is that the auto-cruise function is ON in the auto-cruise operation unit 22, the shift lever is set to the D range, and there is no accelerator and brake operation. The control conditions are not limited to this, and the auto cruise control may be executed from other conditions.

1 vehicle 2 engine 4 transmission (transmission means)
6 Brake 8 Millimeter wave radar 10 Vehicle speed sensor 12 Shift position sensor 14 Engine ECU (Engine output detection means)
16 Brake ECU
18 Transmission ECU
20 auto cruise ECU
22 Auto-cruise operation section 30 Auto-cruise control section 32 Inter-vehicle distance control section (inter-vehicle distance control means)
34 Actual acceleration calculation unit (acceleration detection means)
36 Vehicle load calculation unit (vehicle load calculation means)
38 Rotation speed calculation unit after shift up (engine speed calculation means after shift)
40 Shift control unit (shift control means)

Claims (2)

In an auto cruise control device that automatically drives a vehicle,
Transmission means provided in the vehicle and capable of stepwise shifting the driving force from the engine;
An inter-vehicle distance control means for controlling an inter-vehicle distance from a preceding vehicle traveling in front of the host vehicle;
Acceleration detecting means for detecting the acceleration of the vehicle;
Vehicle load degree calculation means for calculating a vehicle load degree for traveling of the vehicle based on the acceleration detected by the acceleration detection means;
Engine output detecting means for detecting the output of the engine;
A post-shift engine speed calculating means for calculating the engine speed when the gear position of the speed change means is changed to the low gear ratio side;
During execution of the inter-vehicle distance control by the inter-vehicle distance control means, the vehicle load degree calculated by the vehicle load degree calculation means is at least a predetermined vehicle load degree threshold value that can realize the vehicle speed set by the inter-vehicle distance control. Yes, the engine output detected by the engine output detecting means is at least equal to or less than a predetermined engine output threshold capable of realizing the vehicle speed set by the inter-vehicle distance control, and the speed change calculated by the post-shift engine speed calculating means Shift control means for changing the gear position of the speed change means to a low gear ratio side when the subsequent engine speed is at least a predetermined engine speed threshold value capable of realizing a vehicle speed set by the inter-vehicle distance control;
An auto-cruise control device comprising:   2. The automatic cruise control apparatus according to claim 1, wherein the vehicle load degree calculation means is calculated based on a difference between a vehicle acceleration at a reference condition and an acceleration detected by the acceleration detection means.

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