JP2008012967A - Vehicle speed control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the responsiveness of acceleration at the time of the acceleration control of a vehicle. <P>SOLUTION: This vehicle speed control device 10 is provided with an acceleration calculating means 3a calculating the acceleration of the vehicle, a target acceleration setting means 3b setting the target acceleration of the vehicle, a deviation calculating means 3c calculating the deviation of the acceleration calculated by the acceleration calculating means 3a relative to the target acceleration set by the target acceleration setting means 3b, a requested opening calculating means 3d calculating a throttle requested opening based on a computed value obtained by multiplying the deviation of the acceleration calculated by the deviation calculating means 3c and a prescribed control gain value G, and a throttle control means 4 controlling the opening of the throttle valve of an engine based on the throttle requested opening calculated by the requested opening calculating means 3d. At the time of the start of the vehicle acceleration control, the requested opening calculating means 3d increases the prescribed control gain value G. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle speed control device that controls, for example, a vehicle speed to a set vehicle speed.

Conventionally, a vehicle speed control device that calculates a target acceleration based on a traveling vehicle speed that is an actual vehicle speed of a vehicle and a target vehicle speed, and calculates a deviation acceleration of the traveling acceleration that is the actual acceleration of the vehicle with respect to the calculated target acceleration. It is known (see, for example, Patent Document 1). The device drives the throttle valve so that the deviation acceleration becomes zero.
JP-A-9-86224

  In the conventional vehicle speed control device, the vehicle may be changed from the constant speed control (cruise control) state to the acceleration control state. When this acceleration control is changed, the target acceleration increases relatively and the deviation acceleration of the running acceleration with respect to the target acceleration increases, so that the acceleration responsiveness during the acceleration control may be deteriorated. On the other hand, although it is assumed that the control gain is set to be large in advance, acceleration hunting or the like may occur.

  The present invention has been made to solve such problems, and has as its main object to improve the acceleration responsiveness during vehicle acceleration control.

In order to achieve the above object, one embodiment of the present invention provides:
Acceleration calculation means for calculating the acceleration of the vehicle;
Target acceleration setting means for setting the target acceleration of the vehicle;
Deviation calculating means for calculating a deviation of the acceleration calculated by the acceleration calculating means with respect to the target acceleration set by the target acceleration setting means;
Requested opening degree calculating means for calculating a throttle required opening degree based on a calculated value obtained by multiplying the deviation of the acceleration calculated by the deviation calculating means and a predetermined control gain value;
A throttle control means for controlling an opening degree of a throttle valve of an engine based on the required throttle opening degree calculated by the required opening degree calculation means, and a vehicle speed control device comprising:
In the vehicle speed control device, the required opening calculation means increases the predetermined control gain value at the start of acceleration control of the vehicle.

  According to this aspect, at the start of the acceleration control of the vehicle, the required opening degree calculation means increases the predetermined control gain value. Thereby, the acceleration responsiveness at the start of the acceleration control of the vehicle can be improved.

In this one aspect, a first gain value that is a value during constant speed control is set as the predetermined control gain value,
The required opening calculation means sets the predetermined control gain value to a value obtained by adding the first gain value and the second gain value at the start of acceleration control of the vehicle, and gradually after the acceleration control starts. When the predetermined time has elapsed, the first gain value may be set. As a result, at the start of acceleration control, the predetermined control gain value is increased from the first gain value (first gain value + second gain value), thereby improving acceleration responsiveness. Can do. Then, when a predetermined time elapses after the acceleration control is started, the predetermined control gain value is returned to the optimum first gain value during the constant speed control, thereby suppressing the acceleration hunting and stably controlling the constant speed. It can be performed.

  According to the present invention, it is possible to improve acceleration responsiveness during vehicle acceleration control.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a system configuration of a vehicle speed control apparatus according to an embodiment of the present invention. A vehicle speed control device 10 according to the present embodiment is mainly configured by an engine ECU 1 that performs various controls of a vehicle engine.

  An engine ECU (Electronic Control Unit) 1 is composed of a microcomputer, and executes various processes in accordance with control and arithmetic programs, and controls each part of the device 10 (Central Processing Unit), CPU A ROM (Read Only Memory) for storing the execution program, a RAM (Random Access Memory) for storing calculation results, a timer, a counter, an input interface, an output interface, and the like.

  The engine ECU 1 includes an engine control unit 2 that controls the engine, a cruise control unit 3 that controls the vehicle speed to a set speed that is a target vehicle speed, and a throttle control unit 4 that controls the throttle valve 4a. . The engine control unit 2, the cruise control unit 3, and the throttle control unit 4 are realized, for example, by programs stored in the ROM and executed by the CPU.

  The throttle control unit 4 controls the opening degree of the throttle valve 4a via the actuator 4b. In the intake passage for introducing intake air into the combustion chamber of the engine, the above-described throttle valve 4a for adjusting the intake air amount is disposed. An actuator 4b that drives the throttle valve 4a is connected to the throttle valve 4a.

  The throttle control unit 4 controls the opening of the throttle valve 4a by controlling the driving of the actuator 4b, thereby controlling the amount of intake air introduced into the combustion chamber of the engine. For example, the throttle control unit 4 transmits a control signal to the actuator 4b, thereby increasing the opening of the throttle valve 4a and increasing the amount of intake air introduced into the combustion chamber of the engine. Thereby, the driving force of the engine can be increased. On the other hand, the throttle control unit 4 transmits a control signal to the actuator 4b, thereby reducing the opening of the throttle valve 4a and reducing the amount of intake air introduced into the combustion chamber of the engine. Thereby, the driving force of the engine can be reduced.

  The throttle valve 4a is provided with a potentiometer 4c for detecting the opening degree of the throttle valve 4a. The potentiometer 4 c is connected to the throttle control unit 4. The potentiometer 4 c transmits the detected opening of the throttle valve 4 a to the throttle control unit 4. For example, the throttle control unit 4 performs so-called feedback control so that the opening degree of the throttle valve 4a detected by the potentiometer 4c becomes the target opening degree.

  The throttle control unit 4 is connected to a depression amount sensor 5 that detects the depression amount of the accelerator pedal. The throttle control unit 4 controls the driving force of the engine by increasing or decreasing the opening of the throttle valve 4a according to the depression amount of the accelerator pedal detected by the depression amount sensor 5.

  The engine control unit 2 controls the fuel injection valve 2 a for adjusting the fuel injected into the combustion chamber according to the intake air amount into the combustion chamber of the engine controlled by the throttle control unit 4. For example, the engine control unit 2 controls the opening and closing of the fuel injection valve 2a so that the air-fuel ratio in the combustion chamber is optimized according to the amount of intake air introduced into the combustion chamber.

  The cruise control unit 3 performs so-called cruise control (constant speed control) that automatically controls the engine so that the vehicle speed becomes the set speed. The cruise control unit 3 is connected to a vehicle speed sensor 6 that detects the vehicle speed and a cruise switch 7 that outputs a trigger signal for executing cruise control.

  The vehicle speed sensor 6 includes, for example, a wheel speed sensor that is disposed on each wheel and detects the rotation speed of each wheel, and detects the vehicle speed based on the rotation speed of each wheel detected by the wheel speed sensor. The vehicle speed sensor 6 transmits the detected vehicle speed to the cruise control unit 3.

  The cruise switch 7 is a switch that is disposed, for example, in the vicinity of the steering wheel in the passenger compartment and can be switched to an on state or an off state by the driver. When the cruise switch 7 is switched to the on state, the cruise switch 7 transmits an on signal to the cruise control unit 3. On the other hand, when the cruise switch 7 is switched to the off state, the cruise switch 7 transmits an off signal to the cruise control unit 3.

  When the cruise control unit 3 receives the ON signal from the cruise switch 7, the cruise control unit 3 executes cruise control. The cruise control unit 3 increases or decreases the driving force of the engine by increasing or decreasing the opening of the throttle valve 4a so that the vehicle speed detected by the vehicle speed sensor 6 becomes a preset set speed. The set speed is set and stored in the RAM of the engine ECU 1, for example.

  The cruise control unit 3 is connected to a change switch 8 for increasing or decreasing the vehicle speed during cruise control. The change switch 8 is, for example, a switch that is disposed in the vicinity of the steering wheel in the vehicle interior and can be operated by the driver to the speed increasing side or the speed reducing side.

  While the change switch 8 is operated to the speed increasing side, the change switch 8 continuously transmits a speed increasing signal to the cruise control unit 3. The cruise control unit 3 executes acceleration control for increasing the vehicle speed while receiving the speed increase signal from the change switch 8. When the change switch 8 is returned from the speed increasing side to the neutral position, the change switch 8 stops transmitting the speed increasing signal to the cruise control unit 3. When the speed increasing signal is no longer received from the change switch 8, the cruise control unit 3 stores the vehicle speed at that time in the RAM of the engine ECU 1 as a set speed, and executes the cruise control at the stored vehicle speed.

  On the other hand, while the change switch 8 is operated to the deceleration side, the change switch 8 continuously transmits a deceleration signal to the cruise control unit 3. The cruise control unit 3 reduces the vehicle speed while receiving the deceleration signal from the change switch 8. When the change switch 8 is returned from the deceleration side to the neutral position, the change switch 8 stops transmission of the deceleration signal to the cruise control unit 3. When the deceleration signal is no longer received from the change switch 8, the cruise control unit 3 stores the vehicle speed at that time in the RAM of the engine ECU 1 as a set speed, and executes cruise control at the stored vehicle speed.

  The cruise control unit 3 calculates the required throttle opening MA using the following equation (1), and controls the opening of the throttle valve 4a based on the required throttle opening MA. For example, when the cruise control unit 3 receives a speed increase signal from the change switch 8 during cruise control, the cruise control unit 3 calculates the throttle request opening MA using the following equation (1), and the throttle request opening MA is large. In proportion to this, the opening degree of the throttle valve 4a is increased (start of acceleration control).

The cruise controller 3, acceleration calculating unit 3a which calculates the acceleration [Delta] V _n of the vehicle, and the target acceleration setting means 3b for setting a target acceleration D _t of the vehicle, with respect to the target acceleration D _t set by the target acceleration setting means 3b a deviation calculating means 3c for calculating the deviation of the acceleration [Delta] V _n calculated by the acceleration calculation means 3a and _(D t _{-ΔV n),} and the deviation of the acceleration calculated by the deviation calculating means 3c _(D t _{-ΔV n),} A required opening calculation for calculating a throttle required opening MA based on a calculated value G × (D _t −ΔV _n ) obtained by multiplying a predetermined control gain value (hereinafter referred to as a control gain value) G. Means 3d.

The acceleration calculation means 3a calculates the vehicle acceleration ΔV _n by performing differentiation on the vehicle speed V detected by the vehicle speed sensor 6. Target acceleration setting unit 3b includes a set speed which is set as the target vehicle speed, the vehicle speed V detected by the vehicle speed sensor 6, on the basis, calculates the target acceleration D _t, is set.

  Here, for example, when traveling on a flat road, the set speed is increased by the change switch 8 with the vehicle speed detected from the vehicle speed sensor 6 as a starting value when both the depression of the brake pedal and the depression of the accelerator pedal are released. It is a speed value adjusted by being operated to the speed side or the deceleration side.

MA _n = MA _n−1 + G × (D _t −ΔV _n ) × T _sk (1) Equation (1) In the above equation (1), MA _n−1 indicates the throttle required opening calculated previously. _Tsk indicates a skip time (for example, 1 to 2 seconds).

  Incidentally, the control gain value G has conventionally been set to a fixed value that can maintain the vehicle acceleration constant. In this case, for example, when the change switch is operated to the acceleration side and acceleration control is started from the cruise control state, the difference between the set target acceleration and the acceleration calculated by the acceleration calculating means is compared. Therefore, the acceleration response may be deteriorated.

  Therefore, in the vehicle speed control device 10 according to the present embodiment, when the acceleration control is started, the required opening calculation means 3d increases the control gain value G and increases the required throttle opening. Thereby, the responsiveness of acceleration at the time of acceleration control can be improved.

  Specifically, the required opening calculation means 3d increases the control gain value G in the acceleration control by the following equation (2). FIG. 2 is a diagram showing the control gain value G when changed based on the following equation (2), and is a diagram showing an example of the time change of the control gain value G from the start of acceleration control. In FIG. 2, the vertical axis represents the control gain value G, and the horizontal axis represents the elapsed time T from the start of acceleration control.

G = (G1 + G2 × B / K) (2) In the above equation (2), G1 is a first gain value, and is a normal value that maintains a constant acceleration (a gain value during constant speed control). Is set. G2 is a second gain value, and a value (for example, a value substantially the same as or slightly larger than the first gain value G1) that improves acceleration response is obtained and set in advance. K indicates a raising control execution time (hereinafter referred to as a predetermined time) in which the control gain value G is increased from the state of the first gain value G1. The raising control execution time K is set to about 2 seconds, for example, and is stored in advance in the ROM of the engine ECU 1. B is a value obtained by B = K−T (B ≧ 0). Here, T indicates an elapsed time from the start of acceleration control.

  According to the above equation (2), the control gain value G is set to a value obtained by adding the first gain value G1 and the second gain value G2, which are normal values, to the control gain value G when acceleration control is started ( Figure 2). The control gain value G gradually decreases after the acceleration control is started, and becomes the first gain value G1 when a predetermined time K has elapsed after the acceleration control is started.

  FIG. 3 is a diagram illustrating an example of a processing flow when the control gain value G after the acceleration control is started is increased.

  First, the cruise control unit 3 receives a speed increase signal from the change switch 8 and determines whether or not to start acceleration control (S100).

  When the cruise control unit 3 receives the acceleration signal from the change switch 8 and determines that the acceleration control is to be started (Yes in S100), the cruise control unit 3 starts the acceleration control and measures an elapsed time T from the start of the acceleration control. (S110). The cruise control unit 3 measures an elapsed time T from the start of acceleration control, for example, using the timer or counter built in the engine ECU 1.

  On the other hand, when the cruise control unit 3 determines that the acceleration control is not started without receiving the acceleration signal from the change switch 8 (No in S100), the present processing routine is terminated.

  Next, the cruise control unit 3 determines whether or not the elapsed time T from the start of acceleration control is smaller than the predetermined time K (S120).

  When the cruise control unit 3 determines that the elapsed time T from the start of the acceleration control is smaller than the predetermined time K (Yes in S120), the value calculated by the above-described equation (B = K−T) is set to B. Set. On the other hand, when determining that the elapsed time T from the start of acceleration control is equal to or longer than the predetermined time K (No in S120), the cruise control unit 3 sets B to 0 (B = 0) (S140).

  Thereafter, the cruise control unit 3 calculates a control gain value G by the above equation (2) based on the value of B set in the above processing (S150).

  The cruise control unit 3 determines whether or not acceleration control is being performed based on the acceleration signal transmitted from the change switch 8 (S160). When it is determined that the acceleration control is being performed (Yes in S160), the cruise control unit 3 returns to the process of (S120). On the other hand, when the cruise control unit 3 determines that the acceleration control is not being performed (No in S160), the routine by this process is terminated.

  Note that, by changing the control gain value G as described above, the throttle required opening (the solid line in FIG. 4A) in the vehicle speed control device 10 according to the present embodiment at the start of the acceleration control is changed to the conventional value. It can be increased compared with the throttle required opening (dotted line in FIG. 4A) in the vehicle speed control device. Thereby, the responsiveness of acceleration at the time of acceleration control (particularly at the start of acceleration control) can be improved. Note that the throttle opening required in the vehicle speed control device 10 according to the present embodiment increases smoothly as shown by the solid line in FIG. 4A, so that smooth acceleration can be achieved while improving acceleration response. it can. Further, the control gain value G gradually decreases after the start of the acceleration control, and when the predetermined time K elapses, the control gain value G becomes the first gain value G1, which is a normal value. Thus, stable constant speed control for maintaining the vehicle speed at the set speed can be performed.

  Further, by changing the throttle required opening as shown in FIG. 4A, the vehicle speed responsiveness (of FIG. 4B) in the vehicle speed control device 10 according to the present embodiment at the start of acceleration control. The solid line) can be made better than the vehicle speed response in the conventional vehicle speed control device (dotted line in FIG. 4B).

  As described above, in the vehicle speed control device 10 according to the present embodiment, the control gain value G is increased at the start of acceleration control, and the throttle required opening is increased. Thereby, the responsiveness of acceleration at the time of acceleration control can be improved. Further, when the predetermined time K has elapsed from the start of the acceleration control, the control gain value G becomes the first gain value G1, which is the optimum value during cruise control. Stable control can be performed by reliably suppressing hunting.

  As mentioned above, although the best mode for carrying out the present invention has been described using one embodiment, the present invention is not limited to such one embodiment, and within the scope not departing from the gist of the present invention, Various modifications and substitutions can be made to the above-described embodiment.

  In the above embodiment, in the acceleration control, the control gain value G is linearly decreased from (first gain value G1 + second gain value G2) to the first gain value G1 (FIG. 2). The manner of making is not limited to this, and it may be reduced, for example, in an arc shape.

  INDUSTRIAL APPLICABILITY The present invention can be used for a vehicle speed control device that controls a vehicle speed to a set speed.

It is a block diagram which shows the system configuration | structure of the vehicle speed control apparatus which concerns on one Example of this invention. It is a figure which shows an example of the time change of the control gain value from the time of the start of acceleration control. It is a figure which shows an example of the processing flow when increasing the control gain value after the start of acceleration control. (A) It is the figure compared with the throttle demand opening in the vehicle speed control apparatus which concerns on a present Example, and the throttle demand opening in the conventional vehicle speed control apparatus. (B) It is the figure compared with the responsiveness of the vehicle speed in the vehicle speed control apparatus which concerns on a present Example, and the responsiveness of the vehicle speed in the conventional vehicle speed control apparatus.

Explanation of symbols

1 Engine ECU
2 Engine Control Unit 3 Cruise Control Unit 3a Acceleration Calculation Unit 3b Target Acceleration Setting Unit 3c Deviation Calculation Unit 3d Required Opening Calculation Unit 4 Throttle Control Unit 4a Throttle Valve 10 Vehicle Speed Control Device

Claims (2)

Acceleration calculation means for calculating the acceleration of the vehicle;
Target acceleration setting means for setting the target acceleration of the vehicle;
Deviation calculating means for calculating a deviation of the acceleration calculated by the acceleration calculating means with respect to the target acceleration set by the target acceleration setting means;
Requested opening degree calculating means for calculating a throttle required opening degree based on a calculated value obtained by multiplying the deviation of the acceleration calculated by the deviation calculating means and a predetermined control gain value;
A throttle control means for controlling an opening degree of a throttle valve of an engine based on the required throttle opening degree calculated by the required opening degree calculation means, and a vehicle speed control device comprising:
The vehicle speed control device characterized in that, at the start of vehicle acceleration control, the required opening calculation means increases the predetermined control gain value. The vehicle speed control device according to claim 1,
For the predetermined control gain value, a first gain value that is a value at the time of constant speed control is set,
The required opening calculation means sets the predetermined control gain value to a value obtained by adding the first gain value and the second gain value at the start of acceleration control of the vehicle, and gradually after the acceleration control starts. The vehicle speed control device is characterized in that when the predetermined time elapses, the first gain value is set.

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