JP6413818B2 - Stop / restart controller - Google Patents

Description

  The present invention relates to a stop / restart control device that stops an internal combustion engine and restarts the internal combustion engine.

  Conventionally, as this type of stop / restart control device, a braking mechanism operated by a driver during driving of a vehicle, a so-called service brake mechanism, and control of stop and restart of the internal combustion engine according to the hydraulic pressure of the service brake mechanism A device including a control unit is known (for example, see Patent Document 1).

  In the stop / restart control device described in Patent Document 1, when the hydraulic pressure of the service brake mechanism, which fluctuates according to the depression operation of the brake pedal, exceeds a preset first reference hydraulic pressure while the vehicle is stopped In addition, the internal combustion engine is automatically stopped. After the internal combustion engine is stopped, the internal combustion engine is restarted when the hydraulic pressure of the service brake mechanism becomes less than a preset second reference hydraulic pressure. As a result, the internal combustion engine is smoothly and automatically stopped through a driver's operation and restarted.

Patent 3613970

  However, such a stop / restart control apparatus described in Patent Document 1 controls the automatic stop and restart of the internal combustion engine using the hydraulic pressure of the service brake mechanism that fluctuates according to the depression operation of the brake pedal. There are the following problems. That is, the service brake mechanism fluid pressure when the brake pedal is depressed and the service brake mechanism fluid pressure when the brake pedal is returned from the depressed state to the not depressed state. Even if the depression position of the brake pedal is the same, the hydraulic pressure is not always the same.

  For example, there is a possibility that the position of the brake pedal due to the action of the hydraulic pressure when the internal combustion engine is automatically stopped and the position of the brake pedal due to the action of the hydraulic pressure when the internal combustion engine is restarted may be close or separated. . If the position of the brake pedal at the time of automatic stop and the position of the brake pedal at the time of restart are close, the driver will unintentionally restart the engine just by returning the brake pedal a little, and fuel consumption will be worsened. There's a problem. On the other hand, if the position of the brake pedal at the time of automatic stop and the position of the brake pedal at the time of restart are separated, even if the driver returns the brake pedal with the intention to restart, the start of restart is delayed and the start is also delayed As a result, the driver's will and the operation state of the internal combustion engine are deviated, and there is a problem that drivability is lowered.

  The present invention has been made to solve the above-described problems, and provides a stop / restart control device that can prevent a delay in restarting the internal combustion engine and restarting the internal combustion engine that is not intended by the driver. The issue is to provide.

  In order to solve the above-described problem, the present invention provides a stop / restart system including a control unit that stops an internal combustion engine when a predetermined stop condition is satisfied and restarts the internal combustion engine when a predetermined restart condition is satisfied. In the start control device, when the stop condition is satisfied, the control unit stores the brake depression amount when the stop of the internal combustion engine is permitted as a stop stroke amount, and the brake hydraulic pressure and the brake during the stop of the internal combustion engine are stored. When it is detected whether or not the comparison target value representing either one of the depression amounts has exceeded a predetermined value, and it is detected that the comparison target value has exceeded the predetermined value, the brake depression while the internal combustion engine is stopped If the amount returned to the stop stroke amount is one of the restart conditions, and it is not detected that the comparison target value exceeds the predetermined value, Amount write seen, with one of the restart condition that has returned to the correct stroke by subtracting a predetermined amount from the stop stroke.

  ADVANTAGE OF THE INVENTION According to this invention, the stop restart control apparatus which can prevent the delay of restart of the internal combustion engine which a driver | operator does not intend, or restart of an internal combustion engine can be provided.

FIG. 1 is a schematic configuration diagram of a stop / restart control apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing an automatic stop operation of the stop / restart control apparatus according to the embodiment of the present invention. FIG. 3 is a flowchart showing an operation during stop of the stop / restart control apparatus according to the embodiment of the present invention. FIG. 4 is a flowchart showing a restart operation of the stop / restart control apparatus according to the embodiment of the present invention. FIG. 5 is a timing chart for explaining the operation of the automatic stop operation of the stop / restart control apparatus according to the embodiment of the present invention. FIG. 6 is a timing chart for explaining the operation of the stop operation of the stop / restart control apparatus according to the embodiment of the present invention. FIG. 7 is a first timing chart for explaining the action of the restart operation of the stop / restart control apparatus according to the embodiment of the present invention. FIG. 8 is a second timing chart for explaining the action of the restart operation of the stop / restart control apparatus according to the embodiment of the present invention.

  Hereinafter, a vehicle to which a stop / restart control apparatus according to the present invention is applied will be described with reference to FIGS. 1 to 8.

  As shown in FIG. 1, the vehicle 1 of this embodiment includes an engine 2 as an internal combustion engine, a transmission 3, a starter motor 4, a drive shaft 5, a suspension beam 6, front wheel brakes 7L and 7R, and rear wheels. The brakes 8L and 8R, front wheels 11L and 11R, and rear wheels 12L and 12R are included.

  The vehicle 1 further includes a brake device 13, a brake control device 14, a drive circuit 15, a battery 16, and a stop / restart control device 20. The vehicle 1 includes an engine control device (not shown) that controls the engine 2 and a transmission control device (not shown) that controls the transmission 3.

  The vehicle 1 is a so-called FF vehicle including a front engine front drive, but may be a vehicle having another structure. For example, it may be a so-called FR vehicle including a front engine rear drive, or a four-wheel drive vehicle such as a full-time 4WD. The vehicle 1 may be a so-called hybrid vehicle that is driven by a power source of at least one of the engine 2 and a motor.

  The engine 2 is configured by a known internal combustion engine such as a four-cycle gasoline engine or a diesel engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. The engine 2 is constituted by a horizontally mounted engine mounted on the vehicle body so that the axis of the crankshaft (not shown) is directed in the vehicle width direction of the vehicle 1, but the vehicle body is arranged such that the axis of the crankshaft is directed in the front-rear direction of the vehicle 1. It may be a vertically mounted engine.

  The power output from the crankshaft of the engine 2 is shifted by the transmission 3 and transmitted from the drive shaft 5 to the front wheels 11R and 11L. The rear wheels 12L and 12R connected to the suspension beam 6 function as driven wheels that rotate as the front wheels 11L and 11R rotate.

  The transmission 3 is composed of, for example, an automatic transmission (AT). The transmission 3 may be an automatic transmission (AMT) that has a manual transmission (MT) structure and can be automated by an actuator, and includes a clutch and various transmission gears. The so-called dual clutch transmission (DCT) is divided into two systems, odd-numbered and even-numbered, and has a structure that executes clutch connection and transmission gear selection to achieve a gear ratio according to the gearshift instruction. It may be comprised. Moreover, the transmission 3 may be comprised by the automatic transmission (AT) provided with the torque converter, The mechanism which connects two pulleys with a belt and performs a gear shift continuously by changing the diameter of these pulleys. It may be comprised by the continuously variable transmission (CVT: Continuously Variable Transmission) which has.

  The starter motor 4 is a motor that cranks the engine 2 that starts the engine 2 by rotating the crankshaft of the engine 2. The starter motor 4 has a motor main body (not shown) and a starter motor shaft that can be retracted and pushed out in the axial direction with respect to the motor main body.

  The starter motor shaft is provided with a pinion, which meshes with a ring gear provided on the crankshaft of the engine 2 so that power output from the motor body is transmitted to the crankshaft. The starter motor 4 is composed of a motor generator (MG), a so-called generator starter or alternator, which has both a function of an electric motor as a driving source for driving the vehicle 1 and a function of a generator for charging a battery by power generation. Also good.

  The front wheel brake 7L is configured by a braking device that brakes the rotation of the front wheel 11L and decelerates or stops the vehicle 1 and interlocks with a driver's stepping operation on a brake pedal 13c described later. For example, the front wheel brake 7L includes a disc brake (not shown) that rotates together with the drive shaft 5 and is configured by a disc brake that performs braking by sandwiching the disc with friction materials from both side surfaces. It may be.

  For example, the front wheel brake 7L may be configured by a drum brake that is provided with a cylindrical brake drum (not shown) that rotates together with the drive shaft 5 and presses a friction material inside the brake drum to perform braking.

  The front wheel brake 7R and the rear wheel brakes 8L and 8R are respectively configured in the same manner as the front wheel brake 7L. The front wheel brake 7R brakes the rotation of the front wheel 11R, and the rear wheel brake 8L brakes the rotation of the rear wheel 12L. The rear wheel brake 8R brakes the rotation of the rear wheel 12R.

  The brake device 13 includes a master cylinder 13a, a hydraulic pressure passage 13b, a brake pedal 13c, and a booster mechanism (not shown). The hydraulic pressure passage 13b is provided between a hydraulic actuator 22 and a master cylinder 13a, which will be described later, and allows brake fluid to pass therethrough.

  The brake pedal 13c is formed at the lower end of an arm (not shown) with the upper end as a fulcrum, for example, and increases the stepping force by the action of the lever. This arm is connected to the booster mechanism between the upper end and the lower end, and the depression force of the brake pedal 13c is output from the master cylinder 13a to the hydraulic actuator 22 described later via the booster mechanism.

  The booster mechanism is provided between the brake pedal 13c and the master cylinder 13a, and increases the braking force by increasing the brake fluid pressure (MPa), that is, the brake fluid pressure (MPa) as the driver's stepping force. .

  The brake control device 14 is configured by an electronic control unit (ECU). The ECU is constituted by a microcomputer. The microcomputer includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, an output port, and a network module (not shown). It is constituted by.

  The ECU executes arithmetic processing based on data and programs stored in the ROM. The network module can communicate with each ECU that constitutes another control device such as the stop / restart control device 20, an engine control device and a transmission control device (not shown) via a CAN (Controller Area Network).

  A hydraulic actuator 22, a hydraulic pressure sensor 25, a brake stroke sensor 26 and a brake lamp switch 27 are connected to the brake control device 14. The brake control device 14 controls the hydraulic actuator 22 based on information output from the hydraulic pressure sensor 25, the brake stroke sensor 26, and the brake lamp switch 27.

  The hydraulic actuator 22 is connected to the master cylinder 13 a of the brake device 13, the hydraulic pressure passage 23 and the battery 16, and operates with electric power output from the battery 16.

  The hydraulic actuator 22 is configured by a valve mechanism that switches a hydraulic pressure passage such as an electromagnetic valve, for example, and is driven from the master cylinder 13a via the hydraulic pressure passage portion 23 based on a control signal output from the brake control device 14. Then, a predetermined brake fluid pressure is supplied to each of the front wheel brakes 7L and 7R and the rear wheel brakes 8L and 8R to generate a braking force.

  The hydraulic actuator 22 maintains the braking force generated in the front wheel brakes 7L, 7R and the rear wheel brakes 8L, 8R based on the driver's operation of the brake pedal 13c and the control signal output from the brake control device 14. To do.

  Here, whether or not the driver operates the brake pedal 13 c is determined by the brake control device 14 based on information output from the hydraulic pressure sensor 25, the brake stroke sensor 26, and the brake lamp switch 27.

  The presence of operation of the brake pedal 13c means a state in which the operation amount (mm) is detected by the brake stroke sensor 26 due to an action such as the driver depressing the brake pedal 13c.

  No operation of the brake pedal 13c means that the driver's foot is away from the brake pedal 13c or the brake pedal 13c that has been depressed is completely returned, and the operation amount (mm) is determined by the brake stroke sensor 26. It means a state that is not detected.

  The hydraulic pressure passage portion 23 includes front wheel hydraulic pressure passages 23a and 23b and rear wheel hydraulic pressure passages 23c and 23d. The hydraulic pressure is supplied from the front wheel hydraulic pressure passage 23a to the front wheel brake 7R, and the front wheel hydraulic pressure passage 23b. A predetermined brake fluid pressure is supplied to the front wheel brake 7L. Further, a predetermined brake hydraulic pressure is supplied from the rear wheel hydraulic pressure passage 23c to the rear wheel brake 8R, and a predetermined brake hydraulic pressure is supplied from the rear wheel hydraulic pressure passage 23d to the rear wheel brake 8L.

  The brake control device 14 is an ABS (Antilock Brake System) that controls the braking force so as to reduce the occurrence of sliding due to the locking of the front wheels 11L, 11R and the rear wheels 12L, 12R during sudden braking or braking operation on a low friction road. May be provided. Further, the brake control device 14 may be provided with a TCS (Traction Control System) that controls a braking force so as to prevent idling of the front wheels 11L and 11R and the rear wheels 12L and 12R when the vehicle 1 starts and accelerates.

  The drive circuit 15 is configured by a circuit that drives the starter motor 4, and is connected to the starter motor 4, the battery 16, and the stop / restart control device 20. The drive circuit 15 operates with electric power output from the battery 16 and drives the starter motor 4 based on a control signal output from the stop / restart control device 20. The drive circuit 15 may be formed integrally with the starter motor 4 and constitute a part of the starter motor 4.

  The battery 16 is connected to each component such as the drive circuit 15, the hydraulic actuator 22, and various vehicle-mounted devices and control devices (not shown) of the vehicle 1. The battery 16 is composed of a secondary battery such as a lead storage battery or a lithium ion storage battery that supplies power to the drive circuit 15, the hydraulic actuator 22, and each in-vehicle device, and is charged and discharged.

  The hydraulic pressure sensor 25 is configured by a device that measures the pressure of the brake fluid flowing through the hydraulic pressure passage 13b with a pressure sensitive element through a diaphragm such as a stainless diaphragm or a silicon diaphragm, converts the pressure into an electric signal, and outputs the electric signal.

  The brake stroke sensor 26 is a device that is provided on the brake pedal 13c and detects an operation amount (mm) of the brake pedal 13c that is depressed by the driver, that is, a so-called brake depression amount (mm). The brake stroke sensor 26 is configured by a device that obtains a voltage proportional to the depression amount, for example.

  As with the brake stroke sensor 26, the brake lamp switch 27 is a device that is provided in the brake pedal 13c and detects the movement of the arm of the brake pedal 13c to turn on the brake lamp of the vehicle 1.

  The stop / restart control device 20 is configured by an ECU programmed to perform so-called idling stop control that automatically stops when the engine 2 is in an idling state, and has a function as the control unit 41 in the present invention.

  The ECU constituting the stop / restart control device 20 is constituted by a microcomputer. The microcomputer is configured by a microcomputer including a CPU, a RAM, a ROM, a flash memory, an input port, an output port, and a network module (not shown).

  The ECU executes arithmetic processing based on data and programs stored in the ROM. The network module can communicate with each ECU that constitutes another control device such as the brake control device 14, an engine control device and a transmission control device (not shown) via CAN.

  A gradient sensor 42 is connected to the input port of the ECU constituting the stop / restart control device 20. Control objects of the engine 2 and a drive circuit 15 are connected to an output port of the ECU constituting the stop / restart control device 20.

  The gradient sensor 42 is provided on a vehicle body (not shown) of the vehicle 1 and is configured by a device that detects an inclination angle of the vehicle 1, that is, a road surface gradient. Information on the road gradient detected by the gradient sensor 42 is output to the stop / restart control device 20. The gradient sensor 42 only needs to detect the gradient of the road surface, and may be an acceleration sensor that detects the inclination angle of the vehicle 1 by detecting the acceleration that is the rate of change of the speed acting on the vehicle 1 over time. .

  The control unit 41 is configured to automatically stop the driving engine 2 when a predetermined stop condition is satisfied. In the present embodiment, the predetermined stop condition is that the brake hydraulic pressure P detected by the hydraulic pressure sensor 25 is equal to or higher than the specific pressure Pth, the vehicle speed is equal to or lower than a predetermined value (for example, 5 km / h), and is not illustrated. The accelerator pedal is not depressed.

  Here, a map indicating the relationship between the specific pressure Pth and the road surface gradient is experimentally determined and stored in the ROM of the ECU constituting the stop / restart control device 20. The control unit 41 refers to this map and identifies the specific pressure Pth corresponding to the detection information output from the gradient sensor 42.

  It should be noted that the shift position is set to a predetermined position such as neutral, and that torque information detected by a steering steering torque sensor connected to a power steering control device (not shown) is less than a predetermined value. It may be included as a stop condition.

  The control unit 41 stores the brake depression amount when the automatic stop of the engine 2 is permitted when a predetermined stop condition is satisfied in the RAM as a stop stroke amount ST.

  Specifically, the control unit 41 stores the brake depression amount when the brake hydraulic pressure P detected by the hydraulic pressure sensor 25 is equal to or higher than the specific pressure Pth in the RAM as the stop stroke amount ST. ing.

  The control unit 41 compares the brake hydraulic pressure P detected by the hydraulic pressure sensor 25 and the brake depression amount T detected by the brake stroke sensor 26 when the engine 2 is automatically stopped. It is detected whether or not has reached a predetermined value or more.

  Note that the control unit 41 of the present embodiment determines whether or not the maximum value of the comparison target value representing either one of the brake hydraulic pressure P and the brake depression amount T is equal to or greater than a specific pressure Pth or a predetermined amount Tth described later. You may come to detect.

  In the case of such a configuration, for example, when the latest detected value of the brake hydraulic pressure P detected by the hydraulic pressure sensor 25 is larger than the detected value detected by the hydraulic pressure sensor 25 before the previous time, the control unit 41 In addition, the brake fluid pressure P is compared with the specific pressure Pth, and the latest detected value of the brake fluid pressure P detected by the fluid pressure sensor 25 is smaller than the detected value detected by the fluid pressure sensor 25 before the previous time. In this case, control is performed so as not to compare the brake fluid pressure P with the specific pressure Pth.

  In addition, the control unit 41 of the present embodiment controls the relationship between the brake depression amount T detected by the brake stroke sensor 26 and the predetermined amount Tth with the same algorithm as the relationship between the brake hydraulic pressure P and the specific pressure Pth. May be.

  In the present embodiment, the control unit 41 will be described as detecting whether or not the brake depression amount T detected by the brake stroke sensor 26 is equal to or greater than a predetermined amount Tth when the engine 2 is automatically stopped. .

  Here, the predetermined amount Tth is an adaptive value determined experimentally in advance. The brake depression amount T becomes zero when the brake pedal 13c is not depressed, and increases as the brake pedal 13c is depressed.

  In addition, when a predetermined restart condition is satisfied, the control unit 41 restarts the engine 2 that is automatically stopped by driving the starter motor 4 that operates by supplying power from the battery 16 through the drive circuit 15. It is designed to start.

  In the present embodiment, when the control unit 41 detects that the brake depression amount T detected by the brake stroke sensor 26 is equal to or greater than the predetermined amount Tth when the engine 2 is automatically stopped, One of the restart conditions is that the depression amount of the pedal 13c is less than the stop stroke amount ST stored in the RAM.

  That is, when the brake depression amount T is equal to or greater than the predetermined amount Tth, one of the restart conditions is that the depression amount of the brake pedal 13c while the engine 2 is stopped returns to the stop stroke amount ST.

  On the other hand, when the control unit 41 does not detect that the brake depression amount T detected by the brake stroke sensor 26 is equal to or greater than the predetermined amount Tth when the engine 2 is automatically stopped, the brake pedal One restart condition is that the amount of depression 13c is less than a correction stroke amount Tc obtained by subtracting a predetermined correction amount d from the stop stroke amount ST stored in the RAM.

  That is, when the brake depression amount T is not equal to or greater than the predetermined amount Tth, one of the restart conditions is that the depression amount of the brake pedal 13c while the engine 2 is stopped returns to the correction stroke amount Tc.

  Here, the correction amount d is an adaptive value determined experimentally in advance. Further, the control unit 41 further sets a restart condition that all restart prohibiting conditions for prohibiting the restart of the engine 2 are not satisfied.

  Next, the operation of the stop / restart control device 20 of the present embodiment will be described with reference to FIGS. Each operation described below is repeatedly executed in parallel at predetermined time intervals when the control unit 41 detects that an ignition switch (not shown) is turned on.

  FIG. 2 is a flowchart showing an automatic stop operation for automatically stopping the engine 2.

  First, the control unit 41 determines whether or not the engine 2 is automatically stopped (step S1). Here, when it is determined that the engine 2 is automatically stopped, the control unit 41 ends the automatic stop operation. On the other hand, when it is determined that the engine 2 is not automatically stopped, the control unit 41 determines whether or not the brake fluid pressure P detected by the fluid pressure sensor 25 is equal to or higher than the specific pressure Pth (step S2). .

  Here, when it is determined that the brake fluid pressure P is not equal to or higher than the specific pressure Pth, the control unit 41 ends the automatic stop operation. On the other hand, when determining that the brake hydraulic pressure P is equal to or higher than the specific pressure Pth, the control unit 41 stores the brake depression amount T detected by the brake stroke sensor 26 in the RAM as the stop stroke amount ST (step S3). ).

  Next, the control unit 41 determines whether or not all predetermined stop conditions for automatically stopping the engine 2 are satisfied (step S4). Here, when it is determined that all the predetermined stop conditions for automatically stopping the engine 2 are satisfied, the control unit 41 starts the automatic stop of the engine 2 (step S5) and ends the automatic stop operation.

  On the other hand, when it is determined that all the predetermined stop conditions for automatically stopping the engine 2 are not satisfied, the control unit 41 resets the stop stroke amount ST stored in the RAM (step S6) and performs the automatic stop operation. finish.

  FIG. 3 is a flowchart showing an operation during stop when the engine 2 is automatically stopped.

  First, the control unit 41 determines whether or not the engine 2 is automatically stopped (step S11). Here, when it is determined that the engine 2 is not automatically stopped, the control unit 41 ends the stopped operation.

  On the other hand, when determining that the engine 2 is automatically stopped, the control unit 41 determines whether or not a stepping history described later is 1 (step S12). Here, when it is determined that the stepping history is 1, the control unit 41 ends the stopped operation.

  On the other hand, when determining that the stepping history is not 1, the control unit 41 determines whether or not the brake stepping amount T detected by the brake stroke sensor 26 is equal to or greater than the predetermined amount Tth (step S13).

  Here, when it is determined that the brake depression amount T is not equal to or greater than the predetermined amount Tth, the control unit 41 ends the operation during stoppage. On the other hand, when determining that the brake depression amount T is equal to or greater than the predetermined amount Tth, the control unit 41 sets 1 to the depression history indicating that the brake depression amount T is equal to or greater than the predetermined amount Tth (step S14). ), Stop operation during stop. Note that the depression history is reset to 0 or the like when the ignition switch is turned on.

  FIG. 4 is a flowchart showing a restart operation for restarting the engine 2.

  First, the control unit 41 determines whether or not the engine 2 is automatically stopped (step S21). Here, when it is determined that the engine 2 is not automatically stopped, the control unit 41 ends the restart operation. On the other hand, when determining that the engine 2 is automatically stopped, the control unit 41 determines whether or not the stepping history is 1 (step S22).

  Here, when it is determined that the depression history is 1, the control unit 41 determines whether or not the brake depression amount T detected by the brake stroke sensor 26 is less than the stop stroke amount ST stored in the RAM. Judgment is made (step S23).

  On the other hand, if it is determined that the depression history is not 1, the control unit 41 corrects the correction stroke obtained by subtracting the correction amount d from the brake stroke amount T detected by the brake stroke sensor 26 from the stop stroke amount ST stored in the RAM. It is determined whether or not the amount is less than the amount Tc (step S24).

  If it is determined in step S23 that the brake depression amount T is not less than the stop stroke amount ST, or if it is determined in step S24 that the brake depression amount T is not less than the correction stroke amount Tc, the control unit 41 restarts. End the starting operation.

  On the other hand, if it is determined in step S23 that the brake depression amount T is less than the stop stroke amount ST, or if it is determined in step S24 that the brake depression amount T is less than the correction stroke amount Tc, the control unit 41 determines whether or not all restart prohibiting conditions for prohibiting restart of the engine 2 are not satisfied (step S25).

  Here, when it is determined that all the restart prohibition conditions for prohibiting the restart of the engine 2 are not satisfied, the control unit 41 ends the restart operation. On the other hand, when it is determined that all restart prohibiting conditions for prohibiting restart of the engine 2 are not satisfied, the control unit 41 starts restarting the engine 2 and uses the stop stroke amount ST stored in the RAM. Reset to 0 or the like, reset the stepping history to 0 or the like (step S26), and end the restart operation.

  Next, the operation of the operation of the stop / restart control device 20 of the present embodiment will be described with reference to FIGS. FIG. 5 is a timing chart for explaining the operation of the automatic stop operation described with reference to FIG.

  As shown in FIG. 5, at time t <b> 1 to time t <b> 2, the control unit 41 determines that the brake hydraulic pressure P detected by the hydraulic pressure sensor 25 is equal to or higher than the specific pressure Pth, and the brake detected by the brake stroke sensor 26. The depression amount T is stored as a stop stroke amount ST in the RAM by the control unit 41. However, since the vehicle speed V is not less than a predetermined value and not all the predetermined stop conditions for automatically stopping the engine 2 are stored in the RAM. The stopped stroke amount ST is reset by the control unit 41.

  At time t3, the control unit 41 determines that the brake fluid pressure P detected by the fluid pressure sensor 25 is equal to or higher than the specific pressure Pth, and the brake depression amount T detected by the brake stroke sensor 26 is controlled as the stop stroke amount ST. When the vehicle speed V is less than or equal to a predetermined value and all the predetermined stop conditions for automatically stopping the engine 2 are satisfied, the automatic stop of the engine 2 is permitted and started by the control unit 41. As a result, the rotational speed Ne of the engine 2 decreases toward zero.

  FIG. 6 is a timing chart for explaining the operation of the operation during stop described with reference to FIG.

  As shown in FIG. 6, when the brake depression amount T detected by the brake stroke sensor 26 does not become less than the stop stroke amount ST and the brake depression amount T becomes equal to or greater than the predetermined amount Tth at time t11, the control unit 41 The stepping history is set to 1.

  FIG. 7 is a first timing chart for explaining the operation of the restart operation described with reference to FIG. 4, in particular, the restart operation for restarting the engine 2 in a state where the stepping history is set to 1. It is.

  As shown in FIG. 7, at time t21, since the brake depression amount T becomes equal to or greater than the predetermined amount Tth, the depression history is set to 1 by the control unit 41 by the restart operation. At time t22, when the brake depression amount T detected by the brake stroke sensor 26 is less than the stop stroke amount ST stored in the RAM and all the restart prohibiting conditions for prohibiting the restart of the engine 2 are not satisfied, Restart is permitted and started by the control unit 41. As a result, the rotational speed Ne of the engine 2 increases.

  FIG. 8 is a second timing chart for explaining the operation of the restart operation described with reference to FIG. 4, particularly the restart operation for restarting the engine 2 in a state where the stepping history is not set to 1. It is.

  As shown in FIG. 8, at time t31, the brake depression amount T detected by the brake stroke sensor 26 is less than the stop stroke amount ST stored in the RAM. Therefore, the restart of the engine 2 is not started.

  At time t32, the brake depression amount T detected by the brake stroke sensor 26 becomes less than the correction stroke amount Tc obtained by subtracting the correction amount d from the stop stroke amount ST stored in the RAM, and the restart of the engine 2 is prohibited. When all the start prohibition conditions are not satisfied, the restart of the engine 2 is permitted and started by the control unit 41. As a result, the rotational speed Ne of the engine 2 increases.

  As described above, according to the present embodiment, when a predetermined stop condition is satisfied, the brake depression amount when the stop of the engine 2 is permitted is stored as the stop stroke amount ST, and the brake depression when the engine 2 is stopped is stored. One of the restart conditions is that the amount T returns to the stop stroke amount ST.

  Therefore, in the present embodiment, the position of the brake pedal 13c due to the action of the brake fluid pressure while the engine 2 is stopped is close to the position of the brake pedal 13c due to the action of the brake fluid pressure when the engine 2 is restarted. , Can be prevented, and the restart of the engine 2 and the delay of the restart of the engine 2 unintended by the driver can be prevented.

  Further, in the present embodiment, when it is not detected that the brake depression amount T during the stop of the engine 2 is equal to or greater than the predetermined amount Tth, the brake depression amount T during the stop is determined from the stop stroke amount ST. One of the restart conditions is to return to the corrected stroke amount Tc obtained by subtracting the fixed amount d.

  Therefore, in this embodiment, when the brake pedal 13c is not depressed deeply while the engine 2 is stopped, a large stroke amount of the brake pedal 13c until the engine 2 is restarted is ensured. Unintended restart of the engine 2 can be prevented.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 vehicle 2 engine (internal combustion engine)
13c Brake pedal 20 Stop / restart control device 41 Control unit

Claims (2)

In a stop / restart control device having a control unit for stopping the internal combustion engine when a predetermined stop condition is satisfied and restarting the internal combustion engine when a predetermined restart condition is satisfied,
The control unit stores, as a stop stroke amount, a brake depression amount when the stop of the internal combustion engine is permitted when the stop condition is satisfied,
When the internal combustion engine is stopped, it is detected whether a comparison target value representing either one of the brake fluid pressure and the brake depression amount is equal to or greater than a predetermined value,
When it is detected that the comparison target value is equal to or greater than a predetermined value, one of the restart conditions is that the brake depression amount while the internal combustion engine is stopped has returned to the stop stroke amount,
If it is not detected that the comparison target value is greater than or equal to a predetermined value, the brake depression amount while the internal combustion engine is stopped has returned to the corrected stroke amount obtained by subtracting the predetermined amount from the stop stroke amount. Is a stop / restart control apparatus, wherein The stop / restart control device according to claim 1, wherein the control unit stores, as the stop stroke amount, a brake depression amount when it is detected that the brake fluid pressure is equal to or greater than a predetermined value.

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