JP2014224458A - Idle stop control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a deceleration capacity while avoiding a slip of a belt and a chain in a continuously variable transmission when an engine is stopped by an idle stop function during the traveling of a vehicle.SOLUTION: An idle stop control device 100 comprises a deceleration estimation part 160 which estimates deceleration necessary for an own vehicle 1; and an engine control part 162 which stops an engine 18 under a preset condition, and brings the engine into an operation state when the estimated deceleration is not included within an allowable range of the deceleration which is derived from a change of the rotation of a drive wheel side pulley 20b constituting a continuously variable transmission 20.

Description

  The present invention relates to an idle stop control device applied to a vehicle equipped with a continuously variable transmission among vehicles having an idle stop function for automatically stopping an engine of the host vehicle in accordance with driving conditions.

  In recent years, in order to reduce fuel consumption and exhaust gas, vehicles such as automobiles automatically stop the engine when the vehicle stops due to traffic lights or traffic jams, and restart the engine when it is necessary to operate the engine. Various techniques for the so-called idle stop function have been proposed (for example, Patent Document 1).

  By the way, a continuously variable transmission (CVT) is composed of two pulleys fixed to a shaft and a transmission unit such as a belt and a chain for transmitting torque between the two pulleys. The pump is activated by the power of the engine, and the position of the pulley is moved by the hydraulic pressure. In a vehicle equipped with such a continuously variable transmission, a running idle stop technique is disclosed in which the clutch is disconnected when the engine is stopped by the idle stop function, and the transmission torque of the belt is reduced (for example, Patent Documents). 2).

JP 2012-117431 A JP 2012-97790 A

  In the case of a vehicle equipped with a continuously variable transmission as described above, if the engine is stopped by the idle stop function, the hydraulic pressure of the pump that operates with the power of the engine decreases, and the belt or chain of the continuously variable transmission may slip. is there. When the technique disclosed in Patent Document 2 described above is used, the clutch is disconnected when the engine is stopped. Therefore, slippage can be avoided by reducing the transmission torque of the belt. However, when a clutch is provided on the input side from the engine, there is a possibility that slip occurs in the belt or the chain depending on the rotational change of the driving wheel. Further, since the clutch is disconnected, the inertia moment on the engine side from the continuously variable transmission does not act on the wheel side during deceleration of the vehicle, and so-called engine braking does not function. Therefore, when the engine is stopped by the idle stop function, the deceleration capability of the vehicle is reduced.

  In view of such a problem, the present invention can maintain the deceleration capability while avoiding the belt or chain slip in the continuously variable transmission when the engine is stopped by the idle stop function while the vehicle is running. An object is to provide an idle stop control device.

  In order to solve the above-described problem, an idle stop control device of the present invention constitutes a continuously variable transmission by stopping an engine under a preset condition and a deceleration estimating unit that estimates a deceleration required for the host vehicle. An engine control unit that activates the engine when the estimated deceleration is not included in the permitted deceleration range derived from the rotation change of the drive wheel pulley.

  The vehicle is further provided with an obstacle detection unit that detects an obstacle ahead of the host vehicle, and the deceleration estimated by the deceleration estimation unit is a deceleration that can avoid a collision with the detected obstacle, and the engine control unit The engine may be restarted during an avoidance period in which a collision with an obstacle can be avoided at a deceleration allowed by hydraulic pressure when the engine is in an operating state.

  The deceleration estimation unit estimates the deceleration based on the relative distance and relative speed between the obstacle and the host vehicle, and the engine control unit determines the relative distance and relative speed and the hydraulic pressure when the engine is in an operating state. The avoidance period may be specified from the allowable deceleration.

  The vehicle further includes a signal stop identifying unit that identifies a signal color emitted from a traffic light located in front of the host vehicle, and the deceleration estimated by the deceleration estimation unit is determined by the travel regulation when the host vehicle is regulated by the traffic signal. This is the deceleration that can be stopped at the stop position, and the engine control unit restarts the engine during the avoidance period in which the engine can be stopped at the stop position at the deceleration allowed by the hydraulic pressure when the engine is in the operating state. Also good.

  The timing at which the engine control unit restarts the engine may be the latest timing in the avoidance period.

  You may further provide the deceleration adjustment part which adjusts the deceleration of the own vehicle so that the deceleration of the own vehicle may be settled in the permission range.

  According to the present invention, when the engine is stopped by the idle stop function while the vehicle is running, it is possible to maintain the deceleration capability while avoiding the slip of the belt or the chain in the continuously variable transmission.

It is the functional block diagram which showed the schematic structure of the idle stop control apparatus. It is explanatory drawing for demonstrating a luminance image and a distance image. It is explanatory drawing for demonstrating operation | movement of the target object specific | specification part. It is explanatory drawing for demonstrating operation | movement of the deceleration estimation part. It is explanatory drawing for demonstrating the relationship between a rotation change rate and a slip. It is explanatory drawing for demonstrating operation | movement of an engine control part. It is explanatory drawing for demonstrating operation | movement of a deceleration adjustment part. It is the flowchart which showed the flow of the whole process of the idle stop control method.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Vehicle system)
In a vehicle such as an automobile, power is obtained by a driving mechanism such as an engine, and steering or braking of the vehicle is executed by a driver's operation through a steering wheel or a brake pedal. Also, in recent years, the road environment ahead of the host vehicle is imaged by an outside environment recognition unit including an in-vehicle camera mounted on the vehicle, and an object such as a preceding vehicle is identified based on color information and position information in the image, Vehicles equipped with a so-called anti-collision function that avoids a collision with an identified object and keeps the distance between the preceding vehicle and the preceding vehicle at a safe distance (ACC: Adaptive Cruise Control) are becoming widespread. In addition, for the purpose of reducing fuel consumption and exhaust gas, it is equipped with a so-called idle stop function that automatically stops the engine when the vehicle stops due to traffic light or traffic jams, and restarts the engine when the engine needs to be operated. The number of vehicles is increasing. The functions of the vehicle itself such as the drive mechanism, steering, and braking are disclosed in various existing documents, for example, Japanese Patent Application Laid-Open No. 2012-116299 of the same applicant.

  However, in a vehicle equipped with such an idle stop function, when a continuously variable transmission is employed as the transmission, when the engine is stopped by the idle stop function, the hydraulic pressure of the pump that operates with the engine power decreases. At this time, the hydraulic pressure is supplementarily controlled by an electric pump, but the hydraulic pressure is lower than that of a pump that is operated by the power of the engine. For this reason, if the idle stop is performed during traveling, there is a risk of slippage in the belt or chain of the continuously variable transmission. Further, as disclosed in Japanese Patent Application Laid-Open No. 2012-97790 and the like, even if a clutch is provided on the input side from the engine in the continuously variable transmission, depending on the rotational change from the drive wheel side, the slip of the belt or chain May occur.

  Therefore, in the present embodiment, the vehicle environment recognition unit in the collision prevention function described above is used to consider the road environment ahead of the host vehicle, estimate the deceleration required for the host vehicle, and control the engine operating state. An object of the present invention is to avoid a slip of a continuously variable transmission. Hereinafter, the idle stop control device 100 that realizes such an idle stop function will be described in detail.

(Idle stop control device 100)
FIG. 1 is a functional block diagram showing a schematic configuration of the idle stop control device 100. The idle stop control device 100 includes an I / F unit that performs one-way or two-way information exchange with other devices in the host vehicle 1, a RAM, a flash memory, an HDD, and the like. It is composed of a semiconductor integrated circuit including a data holding unit that holds various necessary information, a central processing unit (CPU), a ROM that stores programs, a RAM as a work area, and the like. And a central control unit for controlling. The central control unit functions as the vehicle exterior environment recognition unit 102, the input unit 104, and the control unit 106 in cooperation with the I / F unit and the data holding unit. Hereinafter, the vehicle environment recognition unit 102, the input unit 104, and the control unit 106 will be described.

(External vehicle environment recognition unit 102)
The vehicle exterior environment recognition unit 102 includes an image processing unit 120 and an object specifying unit 122, acquires image data obtained by capturing the road environment ahead of the host vehicle 1, and within the image based on the image data. An object such as a preceding vehicle is specified based on color information and position information. Here, the object is not only a three-dimensional object that exists independently such as a vehicle, a traffic light, a road (traveling zone), a traffic sign, a guardrail, and a building, but also a three-dimensional object part such as a taillight, a blinker, or a lighting part of a traffic light. The thing which can be specified as is included. The outside environment recognition unit 102 is originally mounted on the vehicle in order to perform the collision prevention function.

  The image processing unit 120 continuously acquires image data obtained by imaging the road environment in the detection area in front of the host vehicle 1 from the imaging device 10 every frame (60 fps) for 1/60 seconds, for example, and updates the image data. As a trigger, image processing is performed. Here, the imaging device 10 includes, for example, two imaging devices such as a charge-coupled device (CCD) and a complementary metal-oxide semiconductor (CMOS), and the light of each of the two imaging devices on the traveling direction side of the host vehicle 1. They are spaced apart in a substantially horizontal direction so that the axes are substantially parallel. Further, the imaging device 10 can acquire the brightness of a color image, that is, three hues (red: R, green: G, blue: B) in units of pixels. Here, the color image picked up by the image pickup apparatus 10 is called a luminance image, and is distinguished from a distance image described later.

  FIG. 2 is an explanatory diagram for explaining the luminance image 210 and the distance image 212. When the image processing unit 120 acquires image data from each of the two imaging elements of the imaging device 10, the image processing unit 120 derives parallax (parallax information) using so-called pattern matching. Specifically, a block corresponding to a block arbitrarily extracted from the luminance image 210 based on one image data shown in FIG. 2A (for example, an array of 4 horizontal pixels × 4 vertical pixels) is used as the other image data. Search from the luminance image 210 based on. Here, the horizontal indicates the horizontal direction of the captured image, and the vertical indicates the vertical direction of the captured image. The image processing unit 120 associates the parallax information derived in this way (corresponding to a relative distance described later) with the image data, and generates a distance image 212 shown in FIG. Each block in such a distance image 212 is associated with the parallax of that block. Here, for convenience of explanation, in the distance image 212, blocks from which parallax is derived are represented by black dots.

  Returning to FIG. 1, the object specifying unit 122 acquires the luminance image 210 and the distance image 212 from the image processing unit 120, and obtains the luminance based on the luminance image 210 and the three-dimensional position information based on the distance image 212. It is used to specify which target object (pixel or block) in the detection region 214 corresponds to. At this time, the object specifying unit 122 converts the disparity information for each block in the detection area 214 in the distance image 212 into three-dimensional position information including a horizontal distance, a height, and a relative distance using a so-called stereo method. Convert. Here, the stereo method is a method of deriving a relative distance of the target object from the imaging device 10 from the parallax of the target object by using a triangulation method. At this time, the object specifying unit 122 determines the target part based on the relative distance of the target part and the detected distance on the distance image 212 between the point on the road surface and the target part at the same relative distance as the target part. Deriving the height from the road surface.

  In the present embodiment, the object specifying unit 122 functions as functional units such as the signal stop specifying unit 130 and the obstacle detecting unit 132 according to the object to be specified. The signal stop specifying unit 130 specifies the signal color (red, yellow, blue) emitted from the traffic light located in front of the host vehicle 1. The obstacle detection unit 132 specifies the presence or absence of an obstacle that obstructs the progress of the host vehicle 1 such as a preceding vehicle, a human being, an animal, or a bicycle, and whether or not the preceding vehicle is decelerated when there is a preceding vehicle. . Hereinafter, each functional unit of the object specifying unit 122 will be described in detail.

  FIG. 3 is an explanatory diagram for explaining the operation of the object specifying unit 122. Here, the identification procedure will be described by taking as an example the identification process of the red signal color of the traffic light by the signal stop identification unit 130 among the functional units of the object identification unit 122. First, the signal stop identification unit 130 determines that the luminance of an arbitrary target part in the luminance image 210 is the luminance range of the target (red signal color) (for example, the reference value is the luminance (R) and the luminance (G) is the reference value. Whether or not (R) is 0.5 times or less and luminance (B) is 0.38 times or less of reference value (R) is determined. And if it is contained in the brightness | luminance range used as object, the identification number which shows the said target object will be attached | subjected to the object site | part. Here, as shown in the enlarged view of FIG. 3, the identification number “1” is assigned to the target portion corresponding to the target (red signal color).

  Next, the signal stop specifying unit 130 uses an arbitrary target part as a base point, and the difference between the target part and the horizontal distance and the height (which may further include a relative distance difference) are within a predetermined range. The target parts that are considered to correspond to the same target object (with the same identification number) are grouped, and the target parts are also made an integrated target part group. Here, the predetermined range is represented by a distance in the real space, and can be set to an arbitrary value (for example, 1.0 m). Further, the signal stop specifying unit 130 also applies to a target object (red signal) whose difference in horizontal distance and height difference are within a predetermined range with respect to the target part newly added by grouping. Group target parts with the same color). As a result, if the distances between the target parts with the same identification number are within a predetermined range, all the target parts are grouped. Here, as shown in the enlarged view of FIG. 3, the target part group 220 is formed by grouping the target parts with the identification number “1”.

  Subsequently, the signal stop identification unit 130 determines that the grouped target part group 220 has a height range (for example, 4.5 to 7.0 m) and a width range (for example, 0.05 to 0.05) associated with the target object. 0.2 m), shape (for example, circular shape), etc., it is determined whether or not predetermined conditions are satisfied. Here, regarding the shape, the shape is compared with reference to a template associated with the object in advance (pattern matching), and it is determined that the condition is satisfied because there is a correlation greater than or equal to a predetermined value. If the predetermined condition is satisfied, the grouped target part group 220 is determined as a target (red signal color). In addition, although an example in which the red signal color is specified as the target object is given here, it goes without saying that the signal stop specifying unit 130 can also specify the yellow signal color, the blue signal color, and the like.

  When the target part group 220 has the characteristic peculiar to the target object, it may be determined as the target object on the condition. For example, when the light emitter of the traffic light is configured by an LED (Light Emitting Diode), the light emitter blinks at a cycle (for example, 100 Hz) that cannot be grasped by human eyes. Therefore, the signal stop specifying unit 130 can also determine the object (red signal color) based on the change in the time direction of the luminance of the target portion of the luminance image 210 acquired asynchronously with the blinking timing of the LED.

  When the target part of the luminance image 210 is determined as the target object (red signal color), the signal stop specifying unit 130 extends vertically and horizontally in the traveling direction of the host vehicle 1 on the road surface vertically below the target object. It is determined whether a stop line (white line) is detected. The detection of the stop line can be specified by the same procedure as that for the object (red signal color) using the luminance based on the luminance image 210 and the three-dimensional position information based on the distance image 212.

  When the stop line is detected, the signal stop specifying unit 130 specifies the detected stop line as the planned stop position of the host vehicle 1. Further, when the stop line is not detected, a position close to the own vehicle 1 side by a predetermined distance from the road surface vertically below the target is specified as the planned stop position of the own vehicle 1. Further, when the preceding vehicle has already stopped, the preceding vehicle is detected by the obstacle detection unit 132 and the planned stop position is specified before the preceding vehicle, as will be described later.

  The obstacle detection unit 132 uses the luminance based on the luminance image 210 and the three-dimensional position information based on the distance image 212, and the shape, height and size of the object located within a predetermined relative distance ahead of the host vehicle 1, In addition, an obstacle ahead of the host vehicle 1 is detected based on the relative position of the tail lamp and the blinker on the object.

  Then, the obstacle detection unit 132 detects an obstacle and, when the obstacle is a preceding vehicle, derives a relative distance and a relative speed between the obstacle and the host vehicle 1. Here, the relative speed is derived for each of the luminance image 210 and the distance image 212 acquired every predetermined time with respect to the preceding vehicle, and the change in the derived relative distance is divided by the unit time to obtain the relative speed. Ask.

  Here, the case where the obstacle detection unit 132 detects the preceding vehicle from the luminance image 210 or the like acquired via the imaging device 10 and derives the relative distance and the relative speed has been described. However, the obstacle detection unit 132 detects a preceding vehicle by receiving reflected light when laser light is transmitted, for example, derives a distance from the preceding vehicle based on the light reception timing, and determines a change in relative distance as a unit. The relative speed may be obtained by dividing by time.

  When the identified obstacle is not a preceding vehicle but is an obstacle to the progress of the host vehicle 1, such as a human, an animal, or a bicycle, the obstacle detecting unit 132 performs the same process as the preceding vehicle. Only the relative distance to the obstacle is derived.

(Input unit 104)
Returning to FIG. 1, the input unit 104 includes an accelerator deriving unit 150, a speed deriving unit 152, and an inclination angle deriving unit 154.

  The accelerator deriving unit 150 acquires the amount of depression of the host vehicle 1 on the accelerator pedal 12 and derives the operation amount of the driver to the accelerator pedal 12. The speed deriving unit 152 acquires the detection signal of the speed sensor 14 and derives the speed of the host vehicle 1. The inclination angle deriving unit 154 acquires a detection signal of the inclination angle sensor 16 and derives an inclination angle (pitch angle) in the traveling direction of the host vehicle 1.

(Control unit 106)
The control unit 106 includes a deceleration estimation unit 160, an engine control unit 162, and a deceleration adjustment unit 164. The deceleration estimation unit 160 estimates the deceleration of the host vehicle 1.

  For example, when the signal stop identifying unit 130 detects an object (red signal color), the deceleration estimating unit 160 determines the distance to the planned stop position identified by the signal stop identifying unit 130 and the speed deriving unit 152. The deceleration of the host vehicle 1 is estimated (derived) from the derived speed. That is, the deceleration estimation unit 160 estimates the deceleration that can be stopped at the stop position by the travel restriction when the travel of the host vehicle 1 is restricted by the traffic light.

  When the obstacle detection unit 132 detects an obstacle in front of the host vehicle 1, the deceleration estimated by the deceleration estimation unit 160 is a deceleration that can avoid a collision with the detected obstacle. When the obstacle is a moving body such as a preceding vehicle, the deceleration estimation unit 160 estimates the deceleration based on the relative distance and the relative speed between the obstacle and the host vehicle 1.

  When the planned stop position is specified by the signal stop specifying unit 130 and the obstacle detecting unit 132 detects an obstacle, the deceleration estimating unit 160 decelerates at a deceleration that can avoid collision with the obstacle. Of the planned stop position of the host vehicle 1 and the planned stop position specified by the signal stop specifying unit 130, the deceleration is estimated with priority given to the one having a shorter relative distance to the host vehicle 1 at the time of calculation. .

  FIG. 4 is an explanatory diagram for explaining the operation of the deceleration estimation unit 160. In FIG. 4, the relative distance between the host vehicle 1 and the planned stop position is shown on the horizontal axis, and the relative speed between the host vehicle 1 and the planned stop position is shown on the vertical axis. Here, in order to facilitate understanding, a case where the host vehicle 1 decelerates from a state in which the relative speed is constant will be described as an example.

  In FIG. 4, in the legend x, the vehicle starts decelerating when the relative distance to the stop target is the distance a, and decelerates at a constant deceleration so that it can stop at the planned stop position. In this case, the absolute value of the deceleration (slope of the legend x) is smaller than the legends y and z. As a matter of course, the absolute value of the deceleration increases as the deceleration starts after approaching the planned stop position, as in the legends y and z.

  On the other hand, when the engine 18 is stopped by the idle stop function, the hydraulic pressure for driving the continuously variable transmission 20 mounted on the host vehicle 1 decreases, and the two pulleys constituting the continuously variable transmission 20, the belt, The frictional force of the chain will decrease. Then, in particular, the rotation of the pulley on the tire side (driving wheel side pulley 20b) may cause slippage without suppressing the inertia of the belt or chain.

  Even when the engine 18 is stopped, the minimum hydraulic pressure is maintained by an electric pump or the like. Due to the frictional force that can be generated between the pulley and the belt or chain by this hydraulic pressure, the torque that can be transmitted by the frictional force, etc., the drive wheel side pulley 20b that does not slip when the engine 18 is stopped. The rotation change threshold is determined.

  For example, as in the legend y, it is assumed that the rotational change of the drive wheel side pulley 20b when the deceleration starts when the relative distance is the distance b is equal to a threshold value that does not cause a slip. In other words, in this example, when the deceleration is not started until the relative distance reaches the distance b, there is a possibility of causing a slip if the engine 18 is stopped.

  As described above, here, the cause of the slip of the belt or chain of the continuously variable transmission 20 has been described using the deceleration of the host vehicle 1, but in more detail, it can be described using an index of the rotation change rate. .

  FIG. 5 is an explanatory diagram for explaining the relationship between the rotation change rate and the slip. Between the two pulleys constituting the continuously variable transmission 20 (the pulley on the engine 18 (the engine-side pulley 20a) and the pulley on the tire (the driving wheel-side pulley 20b)), a transmission unit such as a belt or a chain is stretched. It is built.

  Since the drive wheel side pulley 20b is directly connected to the tire via a shaft and a gear, when the rotation speed of the tire changes due to the brake 22 or the slope, the change (tire rotation change) is driven. This is a change in rotation of the wheel-side pulley 20b. On the other hand, the ratio of the rotational change of the driving wheel side pulley 20b to the allowable rotational change of the continuously variable transmission 20 (CVT allowable rotational change) due to the hydraulic pressure and the inertia of the belt or chain is the rotational change rate. That is, the rotation change rate = (CVT allowable rotation change / tire rotation change). It should be noted that the rotational change of the continuously variable transmission 20 has a range that is allowed on both the rotation increasing side and the rotation decreasing side.

  As shown in FIG. 5, the rotation change rate is set to a permitted range including 1 (indicated by hatching in FIG. 5), and within this permitted range, even if the engine 18 is stopped. No slip occurs. On the other hand, if the engine 18 is stopped outside the permitted range, a slip may occur.

  Here, the allowable range of the rotational change rate is specified by conditions such as the moment of inertia of the chain or belt of the continuously variable transmission 20, the belt narrow pressure, the transmission oil temperature, the gear ratio, the tire diameter, and the wheel speed. For example, it is assumed that the deceleration estimation unit 160 appropriately selects a permissible range of the rotation change rate that meets such conditions. Further, an allowable rotation change of the drive wheel side pulley 20b (permitted range of rotation change of the drive wheel side pulley 20b) is derived from the allowable range of the rotation change rate.

  The engine control unit 162 changes the operating state of the engine 18 of the host vehicle 1 according to a predetermined driving condition. For example, the engine control unit 162 changes the operation state of the engine 18 to the stop state when the predetermined engine automatic stop condition is satisfied in the operation state (including the drive state and the idle state) of the engine 18. When the restart condition is satisfied, the operation state is changed. Here, the operating state is a state in which the engine 18 is operated. Of these, the driving state refers to operating the engine 18 with a load applied. In the idle state, the throttle valve is fully closed and no operation is performed. It means that the engine 18 is operated in a load state. The stop state is a state in which the engine 18 is automatically stopped by cutting off the energization of the ignition circuit of the engine 18. When the operating state of the engine 18 transitions from the stopped state to the operating state, the engine 18 is restarted by energizing the starter and the engine ignition circuit as in the case of starting the engine 18.

  FIG. 6 is an explanatory diagram for explaining the operation of the engine control unit 162. In FIG. 6, the horizontal axis indicates time, in FIG. 6A, the vertical axis indicates the vehicle speed of the host vehicle 1, and in FIG. 6B, the vertical axis indicates opening / closing of the accelerator by operating the accelerator pedal 12. Show. In FIG. 6C, the vertical axis indicates ON / OFF of the fuel supply cut processing to the engine 18 during coasting. In FIG. 6D, the vertical axis indicates the stop state and the operating state of the engine 18.

  As shown in FIG. 6B, the vehicle speed shown in FIG. 6A increases until the accelerator opening is closed. After the accelerator opening is closed, the host vehicle 1 gradually decelerates. Yes. Then, as shown in FIG. 6C, unnecessary fuel supply to the engine 18 is cut to suppress fuel consumption during coasting.

  The deceleration estimation unit 160 constantly monitors the outputs from the signal stop identification unit 130 and the obstacle detection unit 132, and estimates the deceleration when the planned stop position is identified by the signal stop identification unit 130 and the obstacle detection unit 132. To do. For example, it is assumed that the scheduled stop position is specified at time t shown in FIG. 6A and the deceleration estimation unit 160 estimates the deceleration.

  The engine control unit 162 determines whether or not the estimated deceleration is included in the deceleration allowable range (indicated by hatching in FIG. 6A). Here, the allowable range of deceleration is derived based on the allowable range of rotation change of the drive wheel side pulley 20b converted from the allowable range of rotation change rate. If the estimated deceleration is included in the permitted range and then the engine automatic stop condition is satisfied, the engine control unit 162 stops the engine 18 as shown in FIG.

  On the other hand, when the estimated deceleration is not included in the allowable deceleration range, the engine control unit 162 operates the engine 18 without stopping the engine 18 even when the engine 18 is in an operating state and the engine automatic stop condition is satisfied. State.

  Further, an obstacle may be detected later with the engine 18 already stopped. In this case, it is assumed that the engine control unit 162 determines that the estimated deceleration is not included in the allowable deceleration range. Then, the engine control unit 162 at any timing of an avoidance period in which a collision with an obstacle can be avoided at a deceleration allowed by the hydraulic pressure when the engine 18 is in an operating state (that is, at a normal time) The engine 18 is restarted.

  Specifically, the case where the legend z shown in FIG. 4 is decelerated at a deceleration allowed by the hydraulic pressure when the engine 18 is in an operating state is shown. When the relative distance is the distance c, the engine 18 is started, and when the distance d is reached, the engine 18 is started. Then, the host vehicle 1 is decelerated at a deceleration allowed by normal hydraulic pressure.

  Therefore, the idle stop control device 100 can reliably avoid a collision with an obstacle without causing the continuously variable transmission 20 to slip.

  Similarly, even when a signal or a stop line is detected later with the engine 18 already stopped, the engine control unit 162 proceeds at a deceleration permitted by the hydraulic pressure when the engine 18 is in an operating state. The engine 18 is restarted at any timing during the avoidance period in which the vehicle can be stopped at the stop position due to the restriction.

  Therefore, the idle stop control device 100 can safely assist the operation of the host vehicle 1 in accordance with the traffic regulation without causing the continuously variable transmission 20 to slip.

  The timing at which the engine control unit 162 restarts the engine 18 is the latest timing in the avoidance period. Even if the engine 18 is restarted in any period in which the relative distance is longer than the distance c including the distance c shown in FIG. 4, the engine can be stopped at the planned stop position. However, by delaying the timing for restarting the engine 18 to the last minute (for example, delaying the timing until the relative distance becomes the distance c), it is possible to secure a long stop period of the engine 18 and further suppress fuel consumption. Become.

  FIG. 7 is an explanatory diagram for explaining the operation of the deceleration adjustment unit 164. As indicated by cross hatching in FIG. 7E, a control range included in the permitted range is set in the permitted range of the rotation change rate. Based on the control range of the rotation change rate, the control range of the deceleration is determined in consideration of the influence of the error factor.

  As shown in FIG. 7D, for example, when the engine 18 stops, the vehicle speed range is specified by the deceleration control range as shown by cross-hatching in FIG. 7A. The deceleration adjustment unit 164 is a continuously variable transmission so that the deceleration of the host vehicle 1 is always within the control range while the host vehicle 1 is in automatic operation by ACC or the like. The gear shift by 20 and the brake 22 are adjusted.

  Also, as shown in Fig. 7 (e), even if an error occurs in the deceleration or rotation change rate and it is out of the control range, the control range of the deceleration or rotation change rate is within the permitted range. It is set narrower than the allowable range of deceleration and rotation rate.

  Thus, the deceleration adjustment unit 164 adjusts the deceleration of the host vehicle 1 so that the deceleration of the host vehicle 1 is within the permitted range. Therefore, the idle stop control device 100 can further suppress the occurrence of slip in the continuously variable transmission 20.

  In addition, the deceleration adjustment unit 164 may determine the subsequent traveling state of the host vehicle 1 based on, for example, the operation amount to the accelerator pedal 12 or the inclination angle of the traveling direction of the host vehicle 1, even if it is not automatic driving. The speed change by the continuously variable transmission 20 and the brake 22 may be finely adjusted so that the deceleration of the host vehicle 1 falls within the permitted range.

(Idle stop control method)
FIG. 8 is a flowchart showing the overall processing flow of the idle stop control method. Here, processing that is periodically executed by interruption while the engine 18 is stopped is shown.

  As shown in FIG. 8, the engine control unit 162 determines whether or not the start timing of the engine 18 has already been determined in the timing determination processing step S206 described later, and the current time is the determined start timing. Is determined (S200). If it is not the start timing (NO in S200), the deceleration estimation unit 160 estimates the deceleration of the host vehicle 1 (S202).

  Subsequently, the engine control unit 162 determines the deceleration specified based on the hydraulic pressure that operates the continuously variable transmission 20 estimated by the deceleration estimation unit 160, more specifically, the above-described rotation specified from the deceleration or the like. It is determined whether or not the change rate is included in the permitted range (S204). When included in the permitted range (YES in S204), the idle stop control process is terminated.

  If not included in the permitted range (NO in S204), the engine control unit 162 determines the start timing of the engine 18 (S206), and ends the idle stop control process. Further, in the start timing determination processing step S200, when the start timing of the engine 18 is reached (YES in S200), the engine control unit 162 starts the engine 18 (S208) and ends the idle stop control process.

  As described above, in the present embodiment, when the engine 18 is stopped by the idle stop function, it is possible to avoid the slip in the continuously variable transmission 20. At this time, since the clutch is not disengaged, the engine brake can be applied and the deceleration capability is maintained.

  Also provided are a program that causes the computer to function as the idle stop control device 100 and a computer-readable storage medium such as a flexible disk, magneto-optical disk, ROM, CD, DVD, or BD on which the program is recorded. Here, the program refers to data processing means described in an arbitrary language or description method.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  Note that each step of the idle stop control method of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processing in parallel or by a subroutine.

  INDUSTRIAL APPLICABILITY The present invention can be used in an idle stop control device that is applied to a vehicle equipped with a continuously variable transmission among vehicles having an idle stop function that automatically stops the engine of the host vehicle according to driving conditions.

DESCRIPTION OF SYMBOLS 1 ... Own vehicle 18 ... Engine 20 ... Continuously variable transmission 130 ... Signal stop specific | specification part 132 ... Obstacle detection part 160 ... Deceleration estimation part 162 ... Engine control part 164 ... Deceleration adjustment part

Claims (6)

A deceleration estimation unit for estimating the deceleration required for the host vehicle;
When the estimated deceleration is not included in the permitted range of deceleration derived from the rotation change of the drive wheel side pulley that constitutes the continuously variable transmission, with the engine stopped under preset conditions An engine control unit for operating the engine;
An idle stop control device comprising: An obstacle detection unit for detecting an obstacle ahead of the host vehicle;
The deceleration estimated by the deceleration estimation unit is a deceleration that can avoid a collision with the detected obstacle,
The engine control unit restarts the engine during an avoidance period in which a collision with the obstacle can be avoided at a deceleration allowed by the hydraulic pressure when the engine is in an operating state. Item 2. The idle stop control device according to Item 1. The deceleration estimation unit estimates the deceleration based on a relative distance and a relative speed between the obstacle and the host vehicle,
The engine control unit identifies the avoidance period from the relative distance and the relative speed, and a deceleration allowed by the hydraulic pressure when the engine is in an operating state. The idle stop control device described. A signal stop identifying unit that identifies a signal color emitted from a traffic light located in front of the host vehicle;
The deceleration estimated by the deceleration estimation unit is a deceleration that can be stopped at a stop position by the travel restriction when there is a travel restriction of the host vehicle by the traffic light,
The engine control unit restarts the engine during an avoidance period in which the engine can be stopped at the stop position at a deceleration allowed by the hydraulic pressure when the engine is in an operating state. The idle stop control device described.   5. The idle stop control device according to claim 2, wherein the timing at which the engine control unit restarts the engine is the latest timing in the avoidance period.   The idle according to any one of claims 1 to 5, further comprising a deceleration adjusting unit that adjusts the deceleration of the host vehicle so that the deceleration of the host vehicle falls within the permitted range. Stop control device.