JP2011173468A - Vehicular control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent sensation of running from degrading, by suppressing undershoot of vehicle speed at deceleration, without sacrificing tracking ability to the speed of target vehicle. <P>SOLUTION: A vehicular control apparatus sets a pseudo-target vehicle speed initialized at a target vehicle speed, when an actual vehicle speed reduces by a deceleration fuel cut, until the deviation of the actual vehicle speed from the target vehicle speed becomes a vehicle speed difference ΔV. The pseudo-target vehicle speed is increased with computing periods, within the range of the actual vehicle speed. With the increase in the speed of the pseudo-target vehicle, a required acceleration is increased from a minimum value to an acceleration necessary for recovery from the deceleration fuel cut. After recovery from the deceleration fuel cut, the pseudo-target vehicle speed is changed gradually to the speed of the target vehicle and the required acceleration is increased to the acceleration necessary for uniform motion (degree of acceleration=0). As a result of this, the actual vehicle speed to the speed of the target vehicle can be matched, while suppressing undershoot, without sacrificing the tracking ability to the target vehicle speed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle control device that controls driving force based on a deviation between an actual vehicle speed and a target vehicle speed.

  In general, in auto-cruise control of a vehicle such as an automobile, the driving force is feedback-controlled based on the deviation between the actual vehicle speed and the target vehicle speed to enable driving at a constant speed. For example, undershoot or overshoot of the vehicle speed may occur.

  In order to cope with this, for example, in Patent Document 1, when the coast switch is operated during constant speed traveling control, the target vehicle speed is decreased at a certain rate when the traveling resistance is more than a certain level, and the traveling resistance is reduced. A technique for preventing undershoot and overshoot of the vehicle speed by setting the target vehicle speed so that the deviation between the actual vehicle speed and the target vehicle speed does not exceed a predetermined value when it is small is disclosed.

JP-A-8-40110

  In the conventional auto cruise control as disclosed in Patent Document 1, the required acceleration during cruise control is calculated based on the deviation between the actual vehicle speed and the target vehicle speed. When the speed becomes higher than the target vehicle speed, a deceleration fuel cut is performed in order to quickly match the actual vehicle speed with the target vehicle speed. For this reason, even if acceleration is instructed after the actual vehicle speed falls below the target vehicle speed, the vehicle does not return immediately after the deceleration fuel cut, and it takes time until the vehicle starts to accelerate and undershoot occurs.

  That is, as shown in FIG. 5, in the state where the actual vehicle speed is higher than the target vehicle speed and the deceleration fuel cut is performed, the required acceleration is a negative minimum value smaller than the acceleration required for constant speed motion (acceleration = 0). It has become. Therefore, even if acceleration is instructed at the timing when the actual vehicle speed coincides with the target vehicle speed (point R ′ in the figure), the requested acceleration immediately returns from the fuel cut (the requested acceleration at which the driving force becomes 0 or more). Driving force = required acceleration × acceleration resistance + running resistance), and the actual vehicle speed undershoots the target vehicle speed.

  If this vehicle speed undershoot occurs, the target vehicle speed is greater than the actual vehicle speed when returning from the deceleration fuel cut, so the acceleration suddenly increases to make the actual vehicle speed match the target vehicle speed, leading to a deterioration in driving feeling. I will. Such a problem can be dealt with by setting the amount of change per unit time of the vehicle speed to be small, that is, setting the acceleration change to be small, but on the other hand, followability to the target vehicle speed is sacrificed, In any case, it is difficult to eliminate the deterioration of the driving feeling.

  The present invention has been made in view of the above circumstances, and controls a vehicle that can suppress undershoot of the vehicle speed during deceleration without sacrificing follow-up performance to the target vehicle speed and prevent deterioration in running feeling. The object is to provide a device.

  In order to achieve the above object, the vehicle control apparatus according to the present invention controls the driving force based on the deviation between the actual vehicle speed and the target vehicle speed, and when the required driving force becomes smaller than a predetermined value, In the control apparatus for a vehicle that performs fuel cut, when the target vehicle speed is smaller than the actual vehicle speed and the deviation between the actual vehicle speed and the target vehicle speed is equal to or less than a predetermined value, the simulation is greater than the target vehicle speed and smaller than the actual vehicle speed. When the target vehicle speed is greater than the actual vehicle speed, the driving force is controlled based on the deviation between the actual vehicle speed and the target vehicle speed, and the target vehicle speed is greater than the actual vehicle speed. A driving force control unit that controls the driving force based on the deviation between the actual vehicle speed and the pseudo target vehicle speed when the deviation is small and the deviation between the actual vehicle speed and the target vehicle speed is a predetermined value or less; To.

  ADVANTAGE OF THE INVENTION According to this invention, the undershoot of the vehicle speed at the time of deceleration can be suppressed without sacrificing the followable | trackability to a target vehicle speed, and the deterioration of driving | running | working feeling can be prevented.

Schematic configuration diagram of engine control system Functional block diagram for constant speed travel control Driving force control routine flowchart Explanatory drawing showing drive force control by pseudo target vehicle speed Explanatory drawing showing undershoot of vehicle speed in conventional auto cruise control

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes an engine, and reference numeral 10 denotes a control device that controls the engine 1, which is an electronic control unit (ECU) that is configured around a microcomputer. The control device 10 includes an intake air amount sensor 3 for detecting the amount of air taken from the intake passage 2 of the engine 1, a crank angle sensor 4 for detecting the engine speed, and a vehicle speed sensor 5 for detecting the vehicle speed. In addition, the engine 1 is connected to the engine 1 via a throttle actuator 7 that opens and closes the throttle valve 6 interposed in the intake passage 2 based on control information from another on-vehicle controller connected via a network (not shown). In addition to controlling the amount of air supplied, the injector 8 is driven to control the fuel injection amount corresponding to the intake air amount, thereby controlling the driving force of the engine 1.

  In addition, a cruise control switch 20 is connected to the control device 10 so that the user (driver) can manually operate at a constant vehicle speed. The cruise control switch 20 is, for example, an operation switch including a push switch and a toggle switch disposed on a steering wheel (not shown). The cruise control switch 20 is a cruise switch for turning ON / OFF constant speed traveling control (auto cruise control), and constant speed traveling control. Cancel switch to cancel, set the vehicle speed at constant speed, set / coast switch to change the vehicle speed at constant speed to the lower side, reset at the previously stored set vehicle speed, set vehicle speed It is composed of a group of switches such as a resume / accelerate switch for changing to the upward side.

  The auto-cruise control by the control device 10 basically realizes the target acceleration determined by experiment or adaptation based on the deviation between the actual vehicle speed detected by the vehicle speed sensor 5 and the target vehicle speed set by the user. This is control for causing the engine 1 to generate the driving force to be generated. At this time, when the vehicle is decelerated from the state where the actual vehicle speed> the target vehicle speed after the override or acceleration operation by the driver's operation, the drive of the injector 8 is stopped and the deceleration fuel cut is performed. If the acceleration is instructed after returning from the deceleration fuel cut when the vehicle speed is reduced to the target vehicle speed, it takes time until the vehicle actually starts to accelerate and undershoot occurs.

  Therefore, as shown in FIG. 2, the control device 10 has a normal target vehicle speed setting unit that sets a target vehicle speed for constant speed traveling according to a user operation input via the cruise control switch 20 as a function of auto-cruise control. 11, a pseudo target vehicle speed setting unit 12 that sets a pseudo target vehicle speed that is a pseudo target vehicle speed with respect to the target vehicle speed, driving force control based on a deviation between the actual vehicle speed and the target vehicle speed, and the actual vehicle speed and the pseudo target vehicle speed. And a driving force control unit 13 that performs driving force control based on the deviation. By providing such a functional configuration, the control device 10 uses the pseudo target vehicle speed to return from the deceleration fuel cut before the actual vehicle speed falls below the target vehicle speed, thereby suppressing the occurrence of undershoot.

  More specifically, the pseudo target vehicle speed setting unit 12 is configured such that when the deviation between the actual vehicle speed and the target vehicle speed is positive and smaller than a predetermined value, that is, the actual vehicle speed is higher than the target vehicle speed, and deceleration by fuel cut is performed. In addition, when the actual vehicle speed is close to the target vehicle speed, a pseudo target vehicle speed that is a pseudo target vehicle speed is set based on the actual vehicle speed and the target vehicle speed. This pseudo target vehicle speed is gradually increased so as to coincide with the actual vehicle speed before the actual vehicle speed falls below the target vehicle speed, and is based on a deviation between the actual vehicle speed and the pseudo target vehicle speed before the actual vehicle speed coincides with the target vehicle speed. The required acceleration is increased (the required acceleration is such that the driving force becomes 0 or more) to return from the deceleration fuel cut. After returning from the deceleration fuel cut, the pseudo target vehicle speed is decreased toward the target vehicle speed, and the actual vehicle speed is made to match the target vehicle speed without undershooting.

  Based on the deviation between the actual vehicle speed and the target vehicle speed, the driving force control unit 13 calculates a required acceleration necessary for realizing the target acceleration determined by experiment or adaptation. Then, after multiplying this required acceleration by acceleration resistance due to the vehicle weight and acceleration, the wheel according to the front projected area of the vehicle, the air resistance coefficient, and the square of the wheel speed, the rolling resistance coefficient and the vehicle weight. The required driving force is calculated by adding running resistance such as rolling resistance.

  The vehicle weight, the air resistance coefficient, and the front projected area are determined and set in advance according to vehicle specifications, and the rolling resistance coefficient is determined and set in advance through experiments or simulations. The wheel speed is detected by a wheel speed sensor (not shown) and the acceleration is calculated from the wheel speed.

  Further, the driving force control unit 13 calculates a target throttle opening based on the required driving force and the engine speed. Then, feedback control is performed so that the actual vehicle speed matches the target vehicle speed by opening and closing the throttle valve 6 via the throttle actuator 7 by PID control or the like so that the opening degree of the throttle valve 6 matches the target throttle opening degree. To do.

  The driving force control based on the above target vehicle speed is basically processing when the actual vehicle speed is smaller than the target vehicle speed. When the actual vehicle speed becomes higher than the target vehicle speed by an acceleration operation or the like, the driving force control unit 13 sets The required acceleration is set to a minimum value that is smaller than the acceleration (acceleration = 0) required for constant speed motion at the target vehicle speed. In the state where the required acceleration is a minimum value, the deceleration fuel cut condition is satisfied, the drive of the injector 8 is stopped, and the opening degree of the throttle valve 6 is held at a predetermined opening degree.

  In the state where the required acceleration is the minimum value and the deceleration fuel cut is performed, when the deviation between the actual vehicle speed and the target vehicle speed is equal to or less than the predetermined value, the pseudo target vehicle speed setting unit 12 performs the normal target vehicle speed as described above. A pseudo target vehicle speed that is larger and smaller than the actual vehicle speed is set. On the other hand, the driving force control unit 13 recalculates the required acceleration based on the deviation (pseudo deviation) between the actual vehicle speed and the pseudo target vehicle speed.

  The required acceleration calculated based on the pseudo deviation between the actual vehicle speed and the pseudo target vehicle speed increases toward the acceleration (acceleration = 0) necessary for constant speed motion as the pseudo target vehicle speed increases. Then, before the actual vehicle speed matches the pseudo target vehicle speed, the required acceleration reaches an acceleration at which the fuel cut can be canceled, and before the actual vehicle speed falls below the target vehicle speed, the deceleration fuel cut is canceled and the vehicle returns. After returning from the deceleration fuel cut, the pseudo target vehicle speed decreases toward the target vehicle speed, the vehicle is decelerated in the state of running resistance-driving force <0 (state of required acceleration <0), and the actual vehicle speed is under The actual vehicle speed can be matched with the target vehicle speed without shooting.

  Specifically, the driving force control in the above-described auto cruise control is executed by software processing executed by the control device 10. Next, the software process for controlling the driving force will be described with reference to the flowchart of FIG.

  The flowchart of FIG. 3 shows a driving force control routine executed at a predetermined cycle. In the driving force control routine, first, in a first step S1, a deviation between the actual vehicle speed detected by the vehicle speed sensor 5 and the set target vehicle speed is calculated. Next, the process proceeds to step S2, and it is checked whether or not a condition is established in which the deviation between the actual vehicle speed and the target vehicle speed is positive and the deviation is within a predetermined range (within the vehicle speed difference ΔV).

  As a result, if the condition of step S2 is not satisfied, that is, even if the deviation between the actual vehicle speed and the target vehicle speed is positive and the vehicle speed is reduced by performing the deceleration fuel cut, the difference from the target vehicle speed is not within the predetermined range. In this case, the process proceeds from step S2 to step S3, and the driving force control based on the deviation between the actual vehicle speed and the target vehicle speed is executed. On the other hand, if the condition of step S2 is satisfied, that is, if the vehicle speed decreases due to the deceleration fuel cut and the difference from the target vehicle speed falls within a predetermined range, the process proceeds from step S2 to step S4, and the first experience of satisfying the condition Check if there is any.

  In step S4, when there is no initial experience of satisfying the condition (when the condition is satisfied for the first time in step S2), the process proceeds from step S4 to step S5, and the pseudo target vehicle speed is set with the target vehicle speed as an initial value (pseudo target vehicle speed = Target vehicle speed). In the subsequent step S6, a control state with the first experience is set using a flag or the like. In step S7, a driving force based on a deviation between the actual vehicle speed and the pseudo target vehicle speed (pseudo deviation; actual vehicle speed-pseudo target vehicle speed) is output, and the routine is exited.

  After experiencing the establishment of the condition of step S2, in the next routine, the process proceeds from step S4 to step S8 to output the driving force based on the pseudo vehicle speed, and whether or not there is an experience in a state where the pseudo deviation is equal to or less than the threshold A in step S9. Find out. If there is no experience below the threshold A, it is checked in step S10 whether or not the pseudo deviation is below the threshold A. If there is no experience below the threshold A, a predetermined value is added to the pseudo target vehicle speed in step S11 to increase the pseudo target vehicle speed toward the target vehicle speed, and the routine is exited.

  That is, as shown in FIG. 4, when the actual vehicle speed is reduced by the deceleration fuel cut and the deviation between the actual vehicle speed and the target vehicle speed becomes the vehicle speed difference ΔV, the pseudo target vehicle speed is set with the target vehicle speed as an initial value. Then, as indicated by a broken line in FIG. 4, a predetermined value is added to the pseudo target vehicle speed every calculation cycle, and the pseudo target vehicle speed is increased within a range not exceeding the actual vehicle speed. At this time, as the pseudo target vehicle speed increases, the required acceleration increases from the negative minimum value toward the acceleration required for returning from the deceleration fuel cut.

  Then, when the pseudo deviation between the actual vehicle speed and the pseudo target vehicle speed becomes equal to or less than the threshold value A, the process proceeds from step S10 to step S12, and a control state with experience of matching the pseudo target vehicle speed is set using a flag or the like. At this time, the required acceleration reaches the acceleration required for returning from the deceleration fuel cut at a timing (point R in FIG. 4) before the actual vehicle speed and the pseudo target vehicle speed coincide with each other, and returns from the deceleration fuel cut.

  After experiencing the state in which the pseudo deviation is equal to or less than the threshold A, the process proceeds from step S9 to step S13, and it is checked whether or not the difference between the pseudo target vehicle speed and the target vehicle speed is equal to or less than the threshold B. If the value does not reach the threshold value B or less, the process proceeds from step S13 to step S14, and a process of subtracting a predetermined value from the pseudo target vehicle speed is performed every calculation cycle by repeating this routine.

  That is, as shown in FIG. 4, after returning from the deceleration fuel cut, the pseudo target vehicle speed is gradually brought closer to the target vehicle speed, and the required acceleration is increased toward the acceleration required for constant speed motion (acceleration = 0). Let Thereby, it can decelerate in the state of driving resistance-driving force <0, and it can match an actual vehicle speed with a target vehicle speed, suppressing an undershoot.

  Thereafter, when the difference between the pseudo target vehicle speed and the target vehicle speed becomes equal to or less than the threshold value B, the process proceeds from step S13 to step S15, the initial experience under the condition that the deviation between the actual vehicle speed and the target vehicle speed is positive and within a predetermined range, , And reset the simulated target vehicle speed matching experience. Thereafter, the routine shifts to normal auto cruise control based on the deviation between the actual vehicle speed and the target vehicle speed.

  As described above, in the present embodiment, when the target vehicle speed is smaller than the actual vehicle speed and the deviation between the actual vehicle speed and the target vehicle speed is a predetermined value or less, the pseudo target vehicle speed that is larger than the target vehicle speed and smaller than the actual vehicle speed is set. Then, the pseudo target vehicle speed is increased toward the actual vehicle speed, and the driving force is controlled based on the deviation between the actual vehicle speed and the pseudo target vehicle speed, so that the required acceleration can be reduced to the acceleration necessary for returning from the deceleration fuel cut at an early stage. Increase the speed and return from the deceleration fuel cut before the actual vehicle speed falls below the target vehicle speed. After returning from the fuel cut, the pseudo target vehicle speed is gradually decreased toward the target vehicle speed, and the vehicle is decelerated in the state of running resistance−driving force <0.

  This suppresses undershoot without sacrificing the ability to follow the target vehicle speed when the vehicle is decelerated from the state where the actual vehicle speed is higher than the target vehicle speed. be able to.

DESCRIPTION OF SYMBOLS 1 Engine 3 Intake air amount sensor 4 Crank angle sensor 5 Vehicle speed sensor 6 Throttle valve 7 Throttle actuator 8 Injector 10 Control apparatus 11 Target vehicle speed setting part 12 Pseudo target vehicle speed setting part 13 Driving force control part 20 Cruise control switch

Claims (4)

In the vehicle control device that controls the driving force based on the deviation between the actual vehicle speed of the vehicle and the target vehicle speed, and executes the fuel cut of the engine when the required driving force becomes smaller than a predetermined value
A pseudo target vehicle speed setting unit that sets a pseudo target vehicle speed that is larger than the target vehicle speed and smaller than the actual vehicle speed when the target vehicle speed is smaller than the actual vehicle speed and a deviation between the actual vehicle speed and the target vehicle speed is a predetermined value or less; ,
When the target vehicle speed is greater than the actual vehicle speed, the driving force is controlled based on the deviation between the actual vehicle speed and the target vehicle speed, and the target vehicle speed is smaller than the actual vehicle speed and the deviation between the actual vehicle speed and the target vehicle speed. And a driving force control unit that controls the driving force based on a deviation between the actual vehicle speed and the pseudo target vehicle speed.   2. The vehicle control device according to claim 1, wherein the pseudo target vehicle speed is increased by adding a predetermined value for each calculation cycle with the target vehicle speed as an initial value.   3. The vehicle control device according to claim 1, wherein the pseudo target vehicle speed is set so as not to exceed the actual vehicle speed.   The predetermined value is subtracted from the pseudo target vehicle speed every calculation cycle when the deviation between the actual vehicle speed and the pseudo target vehicle speed becomes a predetermined value or less. Vehicle control device.

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