JP5703158B2 - Vehicle stop control device - Google Patents

Description

  The present invention relates to a vehicle stop control device that automatically stops and restarts an internal combustion engine and controls the brake device to brake the vehicle while the internal combustion engine is automatically stopped.

  As a conventional stop control device for this type of vehicle, for example, one disclosed in Patent Document 1 is known. The internal combustion engine mounted on the vehicle is stopped when a predetermined stop condition is satisfied, and is restarted when a predetermined restart condition is satisfied, so-called idle stop is performed. Further, this vehicle has a service brake mechanism operated by a brake pedal and a parking brake operated manually. In this stop control device, a state in which the pressure in the master cylinder of the service brake mechanism (hereinafter referred to as “master cylinder pressure”) exceeds a predetermined first reference hydraulic pressure after the brake pedal is depressed and the vehicle stops is predetermined. When the time continues, it is determined that the stop condition is satisfied, and the internal combustion engine is stopped. Thereafter, as the amount of depression of the brake pedal decreases, the master cylinder pressure decreases, and when the state where the master cylinder pressure falls below the second reference hydraulic pressure smaller than the first reference hydraulic pressure continues for a predetermined time, the restart condition Is determined, and the internal combustion engine is restarted.

  An electric parking brake is known as a braking device that automatically brakes a vehicle, and is disclosed in, for example, Patent Document 2. The electric parking brake operates when the vehicle is stopped, the amount of depression of the brake pedal is larger than a predetermined first threshold value, and the state where the accelerator pedal is not depressed is continued for a predetermined time. By rotating forward, the brake pad is pressed against the brake disc, and the motor is stopped in that state. Thereby, the braking state is maintained. Thereafter, when the accelerator pedal is depressed in a state where the brake pedal is released, the brake is released from the brake disk by reversing the motor to release the brake pad.

  Further, when the amount of depression of the brake pedal is larger than a predetermined second threshold value (> first threshold value), it is assumed that the pressing force of the brake pad becomes larger, assuming that the vehicle is stopped on the uphill. Accordingly, the vehicle is prevented from moving backward when starting on an uphill.

Japanese Patent No. 3613970 JP 2007-176191 A

  As described above, in the stop control device of Patent Document 1, the internal combustion engine is restarted when the master cylinder pressure decreases. For this reason, in order to continue idling stop, it is necessary to continue to step on the brake pedal, which is a burden on the driver. Further, when the amount of depression of the brake pedal is unintentionally reduced due to driver's carelessness, the internal combustion engine is restarted earlier than the timing suitable for starting, resulting in deterioration of fuel consumption.

  In addition, when the electric parking brake of Patent Document 2 is applied to the stop control device of Patent Document 1, even if the internal combustion engine is restarted by releasing the brake pedal, the electric parking brake is subsequently applied until the accelerator pedal is depressed. Since the braking by is not released, the fuel is wasted during that time, the fuel consumption is deteriorated, and the start is delayed. In order to solve such a problem, for example, when the internal combustion engine is restarted simultaneously with the depression of the accelerator pedal, the braking is released before the output of the internal combustion engine is generated. The vehicle cannot be started smoothly, for example, the vehicle may move backward.

  The present invention has been made to solve the above problems, and includes an internal combustion engine that is automatically stopped and restarted, and a braking device that automatically brakes the vehicle while the internal combustion engine is stopped. In some cases, an object of the present invention is to provide a vehicle stop control device capable of realizing smooth start of the vehicle and improvement of fuel consumption by appropriately controlling them.

In order to achieve the above object, the invention according to claim 1 stops the internal combustion engine 3 when a predetermined stop condition is satisfied, restarts when the predetermined restart condition is satisfied, and stops. A vehicle stop control device 1 that controls a vehicle V to be braked by operating a braking device (a parking brake 60 in the embodiment (hereinafter, the same in this section)) when a condition is satisfied, The restart condition determining means (ECU 2, step 3 in FIG. 4) for determining that the restart condition is satisfied when the accelerator pedal is depressed, and the gradient (inclination angle AOI) of the road surface on which the vehicle V is stopped. A target rotation for setting a restart target rotational speed NECMDRST at the time of restart of the internal combustion engine 3 in accordance with the gradient detecting means (inclination angle sensor 25) to be detected and the detected road surface gradient. Setting means and (ECU 2, step 62,64,65 in FIG. 8), the rotational speed of the internal combustion engine 3 (engine speed NE) is not the rotational speed becomes the output of the engine 3 in response to operation of the accelerator pedal Further, output control means (ECU 2, step 66 in FIG. 8) for controlling the output of the internal combustion engine 3 (fuel injection amount QINJ) so that the set target rotational speed NECMDRST at the restart is established, and establishment of the restart condition Braking release timing setting means (ECU2, steps 72, 76, 79 in FIG. 9) for setting a brake release timing (release end time TBRKOFF) for releasing the braking of the braking device later according to the gradient of the road surface , When the detected slope of the road surface is a downward slope, the target rotational speed setting means sets the restart target rotational speed NECMDRST smaller than when it is flat. (Step 62 in FIG. 8), the brake release timing setting means sets the brake release timing to an earlier timing (step 72 in FIG. 9), and when the detected road gradient is an upward gradient, it is flat. The target rotational speed setting means sets the restart target rotational speed NECMDRST to a larger value (step 65 in FIG. 8), and the brake release timing setting means sets the brake release timing to a later timing. (Step 79 in FIG. 9) .

  This internal combustion engine is mounted on a vehicle and is stopped when a predetermined stop condition is satisfied, and is restarted when a predetermined restart condition is satisfied, so-called idle stop is performed. . Further, the brake device is operated to brake the vehicle during the idle stop where the stop condition is satisfied.

  Further, according to this vehicle stop control device, when the accelerator pedal is depressed, it is determined that the restart condition is satisfied, and the restart is performed. Therefore, even if the brake pedal is released during the idle stop, the idle stop is continued unless the accelerator pedal is depressed, so that it is not necessary to continue to depress the brake pedal for the continuation. In addition, braking of the vehicle during that time is ensured by a braking device.

  In addition, the slope of the road surface on which the vehicle is stopped during the idle stop is detected, and the restart target rotational speed is set according to the detected road slope, so that the rotational speed of the internal combustion engine is The output of the internal combustion engine is controlled so as to reach the target rotational speed at restart. Furthermore, a brake release timing for releasing the braking of the braking device after the restart condition is satisfied is set according to the detected road surface gradient.

  If the slope of the road surface on which the vehicle is stopped is different, the behavior of the vehicle at the time of start at the time of restart is different. Therefore, as described above, the target rotational speed at restart is set according to the detected road gradient, and the output of the internal combustion engine is controlled, so that the vehicle behavior assumed according to the road gradient is obtained. The vehicle can be appropriately driven and started by the output of a suitable internal combustion engine. Further, by setting the braking release timing of the braking device according to the detected road surface gradient, the braking device can be released at a timing suitable for the behavior of the vehicle.

  As described above, when the internal combustion engine is restarted, it is possible to appropriately control the output of the internal combustion engine and the timing of releasing the braking of the vehicle by the braking device, thereby realizing a smooth start of the vehicle and an improvement in fuel consumption. Can do.

Further , according to the above configuration, when the road surface gradient detected during the idling stop is a downward gradient, the restart target rotation speed is set to a smaller value as compared with a flat gradient and braking is performed. Set the release timing to an earlier timing. If the road surface on which the vehicle in idling stop is on a downward slope, when the internal combustion engine is restarted after that, even if the output of the internal combustion engine is not rising, the braking of the vehicle by the braking device is released. Then, the vehicle moves forward by its own weight. Therefore, by releasing the braking by the braking device at an earlier timing, it is possible to avoid the start of the vehicle in the braking state (brake dragging), to smoothly start the vehicle, and to improve the fuel consumption.

  On the down slope, the output of the internal combustion engine required for starting the vehicle is smaller than that in the flat case. Therefore, when the detected road surface slope is a downward slope, the restart target rotation speed is set to a smaller value and the output of the internal combustion engine is reduced, thereby preventing sudden start due to excessive output, The vehicle can be started smoothly on a downward slope, and the fuel consumption can be further improved.

Further, according to the above configuration, when the road gradient detected during the idle stop is an upward gradient, the restart target rotation speed is set to a larger value as compared with a flat gradient, and braking is performed. Set the release timing to a later timing. When the road surface on which the vehicle in idle stop is stopped is an uphill slope, when the internal combustion engine is restarted after that, if the braking of the vehicle by the braking device is released before the output of the internal combustion engine rises, the vehicle May retreat due to its own weight. Therefore, by releasing the braking by the braking device at a later timing, the braking can be released after the output of the internal combustion engine rises, and the vehicle can be prevented from retreating at the start.

  On the uphill, the output of the internal combustion engine necessary for starting the vehicle is larger than when it is flat. Therefore, when the detected road surface gradient is an upward gradient, the restart target rotation speed is set to a larger value, and the output of the internal combustion engine is further increased, thereby preventing the backlash at the start. It is possible to smoothly start the vehicle on a slope.

According to a second aspect of the present invention, in the vehicle stop control device 1 according to the first aspect, the vehicle speed detecting means (vehicle speed sensor 22) for detecting the speed of the vehicle V (vehicle speed VP) and the opening degree of the accelerator pedal (accelerator) And an accelerator opening degree detecting means (accelerator opening degree sensor 23) for detecting the opening degree AP), and the output control means has a predetermined elapsed time (timer value TMST) after the restart condition is satisfied. When the detected speed of the vehicle V is equal to or higher than the predetermined speed VREF, or when the detected opening of the accelerator pedal is equal to or higher than the predetermined opening APREF, the internal combustion engine 3 according to the opening of the accelerator pedal. Is controlled (steps 10, 11, 12, and 14 in FIG. 4).

  According to this configuration, after the restart condition of the internal combustion engine is satisfied, when the following condition is satisfied, the control of the output of the internal combustion engine is controlled according to the opening of the accelerator pedal instead of the target rotational speed at the time of restart. Do it. That is, when the detected opening degree of the accelerator pedal is equal to or greater than the predetermined opening degree, the output of the internal combustion engine is controlled in accordance with the opening degree of the accelerator pedal, assuming that the acceleration request at the time of start by the driver is high. As a result, the vehicle can be started while satisfactorily responding to the driver's acceleration request, and drivability can be improved.

  Further, when the elapsed time after the restart condition is satisfied is equal to or longer than a predetermined time, or when the detected vehicle speed is equal to or higher than the predetermined speed, it is determined that the vehicle has started and the vehicle has shifted to normal travel. The output of the internal combustion engine is controlled according to the degree of opening. As a result, the vehicle can smoothly shift from starting to normal traveling.

It is a figure showing roughly the vehicles to which the stop control device by this embodiment is applied. It is a block diagram of a stop control device. It is sectional drawing which shows schematic structure of a parking brake. It is a flowchart which shows the control processing of a vehicle. It is a flowchart which shows the stop condition determination process of an internal combustion engine. It is a flowchart which shows the control processing at the time of restart. It is a flowchart which shows a gradient determination process. It is a flowchart which shows the output control process of an internal combustion engine. It is a flowchart which shows the setting process of a brake parameter. It is a flowchart which shows the release control process of a parking brake. It is a timing chart which shows the operation example obtained by control processing about the case where the road surface where the vehicle stopped is flat. It is a timing chart which shows the operation example obtained by control processing about the case where the road surface where the vehicle stopped is a downward slope. It is a timing chart which shows the operation example obtained by control processing about the case where the road surface where the vehicle stopped is an uphill.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows a vehicle V to which a vehicle stop control device 1 according to this embodiment is applied. As shown in the figure, the vehicle V is a front-wheel drive type vehicle having left and right front wheels WF and WF and rear wheels WR and WR, and is an internal combustion engine (hereinafter referred to as “engine”) mounted horizontally on the front portion thereof. 3), an automatic transmission 4 for shifting the power of the engine 3, and the like.

  The engine 3 is a gasoline engine, and its output is controlled according to the fuel injection amount QINJ supplied from the fuel injection valve 8 (see FIG. 2). The automatic transmission 4 includes a torque converter coupled to the output shaft of the engine 3, a shift lever capable of selecting eight shift positions consisting of “1, 2, 3, D4, D5, N, R, and P”, A gear mechanism or the like that can be switched to six types of gear positions including a 1st to 5th speed position and a reverse position is provided (none of which is shown).

  The output shaft (not shown) of the torque converter of the automatic transmission 4 is connected to the front wheels WF and WF via the final reduction mechanism 5 and the left and right drive shafts 6 and 6, thereby Is transmitted to the front wheels WF and WF.

  A foot brake 50 for braking the vehicle V is provided on each front wheel WF and each rear wheel WR. The foot brake 50 is of a disc type, and includes a disc 51 integrated with each front wheel WF and rear wheel WR, a pair of brake pads (not shown) disposed on both sides thereof, and a hydraulic circuit (not shown). )have. When a brake pedal (not shown) is stepped on by the driver, the brake pads are operated in the front wheels WF and the rear wheels WR by the hydraulic pressure supplied from the hydraulic circuit, and the vehicle 51 Braked. The braking force FFBRK of the foot brake 50 increases as the amount of depression of the brake pedal increases.

  Furthermore, each rear wheel WR is provided with an electric parking brake 60 that operates separately from the foot brake 50 described above. As shown in FIG. 3, the parking brake 60 is a caliper body 61 fixed to the vehicle body, a nut 62 fixed in the caliper body 61, the left and right directions extending into the caliper body 61, and screwed into the nut 62. A long screw 63, a pair of brake pads 64a and 64b, and a motor 65 are provided.

  The caliper body 61 is formed with a recess 61a so as to be adjacent to one end of the long screw 63, and the pair of brake pads 64a and 64b are accommodated in the recess 61a. One brake pad 64 a is fixed to the wall surface of the recess 61 a, and the other brake pad 64 b is attached to one end of the long screw 63. Both brake pads 64a and 64b are opposed to each other, and the disk 51 is disposed between them.

  A rotating shaft 65 a of the motor 65 is fixed to the other end of the long screw 63, and the motor 65 is covered with a cover 66 fixed to the caliper body 61. The motor 65 is connected to the ECU 2 described later, and its operation is controlled by a control signal from the ECU 2.

  With the above configuration, when the motor 65 is rotated forward, the long screw 63 moves to the disk 51 side (left direction in the figure) while rotating, and accordingly, the brake pad 64b and the brake that move integrally with the long screw 63 The disc 51 is sandwiched between the pad 64a and the rear wheel WR is braked. The braking force FPBRK of the parking brake 60 at this time is determined according to the pressing amount of the brake pads 64a and 64b, and the pressing amount is controlled by the ECU 2 controlling the rotation angle of the motor 65.

  On the other hand, when the motor 65 is reversed from that state, the brake pad 64b moves to the motor 65 side together with the long screw 63, so that the braking of the rear wheel WR is released.

  A crank angle sensor 21 is provided on the crankshaft 3a of the engine 3 (see FIG. 2). The crank angle sensor 21 outputs a CRK signal, which is a pulse signal, to the ECU 2 at every predetermined crank angle (for example, 30 °) with the rotation of the crankshaft 3a. The ECU 2 calculates the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal.

  Further, as shown in FIG. 2, the ECU 2 receives from the vehicle speed sensor 22 a detection signal indicating the vehicle speed VP, which is the vehicle speed, from the accelerator opening sensor 23 to the opening of an accelerator pedal (not shown) A detection signal indicating AP (referred to as “accelerator opening”) is detected from the shift position sensor 24, a detection signal indicating the shift position of the shift lever is detected from the tilt angle sensor 25, and indicates a tilt angle AOI in the front-rear direction of the vehicle V. Are output respectively.

  Further, the ECU 2 outputs a detection signal representing a current / voltage input / output to / from a battery (not shown) as a power source of the starter 41 from the current / voltage sensor 26. The ECU 2 calculates the remaining charge (hereinafter referred to as “remaining battery”) SOC of the battery based on this detection signal.

  Further, a detection signal indicating the on / off state of the ignition switch 31 is output to the ECU 2, and a detection signal indicating the on / off state of the brake pedal is output from the brake switch 32. When the ignition switch 31 is turned on while the engine 3 is stopped, the starter 41 connected to the crankshaft 3a is operated, whereby the engine 3 is cranked and started. Further, when the ignition switch 31 is turned off during the operation of the engine 3, the engine 3 is stopped.

  The ECU 2 is constituted by a microcomputer including a CPU, a RAM, a ROM, an input interface (all not shown), and the like. The ECU 2 executes various control processes of the engine 3 based on the control programs stored in the ROM in accordance with the detection signals of the various sensors 21 to 26 and the switches 31 and 32 described above.

  In the present embodiment, the ECU 2 corresponds to a restart condition determining unit, a target rotational speed setting unit, an output control unit, and a brake release timing setting unit.

  Next, a control process for the vehicle V according to the embodiment of the present invention will be described with reference to FIGS. This control process mainly controls idle stop and restart of the engine 3 and is executed at predetermined time intervals.

FIG. 4 shows the main routine. In this process, first, a stop condition determination process for the engine 3 is executed in step 1 (illustrated as “S1”, hereinafter the same). FIG. 5 shows the subroutine. In this process, first, in steps 21 to 27, it is respectively determined whether or not the following conditions (a) to (g) are satisfied.
(A) The ignition switch (SW) 31 is in an ON state. (B) The engine speed NE is equal to or higher than a predetermined value NEISTP. (C) The vehicle speed VP is equal to or lower than a predetermined value VPREF. (D) Accelerator opening AP (E) The shift position (SP) is other than P, R, N. (f) The brake switch (SW) 32 is in an ON state. (G) The remaining battery charge SOC is a predetermined value SOCISTP. That is more

  When all of these conditions (a) to (g) are satisfied, it is determined that the stop condition is satisfied, and in step 28, the idle stop flag F_IDLSTP is set to “1” in order to indicate that. Then, this process ends. When the idle stop flag F_IDLSTP is set to “1” during the operation of the engine 3, an idle stop for automatically stopping the engine 3 is started.

  On the other hand, when any of the answers of steps 21 to 27 is NO and any of the conditions (a) to (g) is not satisfied, it is determined that the stop condition is not satisfied, and this is expressed. In step 29, the idle stop flag F_IDLSTP is set to "0", and this process is terminated.

  Returning to FIG. 4, in step 2 following step 1, it is determined whether or not the idle stop flag F_IDLSTP is “1”. If the answer is YES and the engine is idling, it is determined in step 3 whether or not the accelerator opening AP is equal to or greater than a predetermined starting opening APST. When this answer is NO, the idle stop control is executed (step 4), thereby continuing the idle stop and terminating the present process.

  On the other hand, if the answer to step 3 is YES and AP ≧ APST, it is determined that the idle stop should be terminated, the idle stop flag F_IDLSTP is reset to “0” (step 5), and the restart flag F_RESTART is set. At the same time as setting to “1” (step 6), the timer value TMRST of the up-counting restart timer is reset to 0 (step 7).

  Next, in step 8, a restart time control process for restarting the engine 3 is executed, and the process of FIG. 4 ends. FIG. 6 shows a subroutine of the control process at restart. In this process, first, in step 41, it is determined whether or not the previous value F_RESTARTZ of the restart flag is “1”. If the answer is NO and immediately after starting the restart control, in steps 42 to 44, the gradient determination process, the output control process, and the brake parameter setting process are executed, and then the process proceeds to step 45 to be described later. On the other hand, if the answer to step 41 is YES and it is not immediately after the start of restart control, steps 42 to 44 are skipped and the process proceeds to step 45.

  FIG. 7 shows the gradient determination process executed in step 42. In this process, first, in step 51, it is determined whether or not the inclination angle AOI detected by the inclination angle sensor 25 is equal to or less than a first predetermined angle AREFL (eg, −4 °) that is a negative value near zero. . When the answer is YES, it is determined that the road surface on which the vehicle V was stopped during the idling stop (hereinafter referred to as “stop road surface”) is a downward slope, and in order to indicate this, in step 52, the gradient flag F_SLP Is set to “1”, and this process is terminated.

  On the other hand, if the answer to step 51 is NO and AOI> AREFL, whether or not the inclination angle AOI is greater than or equal to a second predetermined angle AREFH (eg, 4 °) that is a positive value near zero in step 53. Is determined. If the answer is NO and AREFL <AOI <AREFH, it is determined that the stop road surface is flat, and in order to indicate that, the gradient flag F_SLP is set to “2” in step 54, and this processing is terminated. To do.

  On the other hand, if the answer to step 53 is YES and AOI ≧ AREFH, it is determined that the stop road surface is an ascending slope. In order to express this, in step 55, the gradient flag F_SLP is set to “3”. This process ends.

  FIG. 8 shows the output control process of the engine 3 executed in step 43 of FIG. In this process, first, in step 61, it is determined whether or not the gradient flag F_SLP is “1”. If the answer is YES and the stop road surface is on a downward slope, in step 62, the restart target rotational speed NECMDRST is set to a first predetermined rotational speed NEREF1 (for example, 900 rpm).

  On the other hand, when the answer to step 61 is NO, it is determined in step 63 whether or not the gradient flag F_SLP is “2”. If the answer is YES and the stop road surface is flat, in step 64, the restart target rotational speed NECMDRST is set to a second predetermined rotational speed NEREF2 (for example, 1100 rpm) larger than the first predetermined rotational speed NEREF1.

  On the other hand, when the answer to step 63 is NO, that is, when the gradient flag F_SLP is “3” and the stop road surface is an upward gradient, in step 65, the restart target rotational speed NECMDRST is set to the second predetermined rotational speed. A third predetermined rotational speed NEREF3 (for example, 1300 rpm) larger than NEREF2 is set.

  In step 66 following step 62, 64 or 65, the fuel injection amount QINJ is calculated in accordance with the set restart target rotational speed NECMDRST, and this process is terminated. As a result, the output of the engine 3 corresponding to the fuel injection amount QINJ is obtained, whereby the engine speed NE is controlled to the restart target speed NECMDRST.

  FIG. 9 shows a brake parameter setting process executed in step 44 of FIG. The brake parameters include a release start time TMOTON, a release end time TBRKOFF, and a rotation speed of the motor 65 (hereinafter referred to as “motor rotation speed”) when the parking brake 60 is released by the motor 65 when the engine 3 is restarted. RTOMOT is set. Note that the release start time TMOTON and the release end time TBRKOFF are expressed starting from the start of the restart control of the engine 3.

  In this process, first, in step 71, it is determined whether or not the gradient flag F_SLP is “1”. If the answer is YES and the stop road surface is on a downward slope, the release end time TBRKOFF is set to the first predetermined time TBRK1 (for example, 0.2 sec), and the release start time TMOTON is set to 0 (steps 72 and 73). Further, the motor rotation speed ROTOMOT is set to the first predetermined speed RREF1 so as to meet these settings (step 74), and this process is terminated.

  On the other hand, when the answer to step 71 is NO, it is determined in step 75 whether or not the gradient flag F_SLP is “2”. When the answer is YES and the stop road surface is flat, the release end time TBRKOFF is set to a second predetermined time TBRK2 (for example, 0.4 sec) larger than the first predetermined time TBRK1, and the release start time TMOTON is set to 0 ( Steps 76 and 77). Further, the motor rotational speed ROTOMOT is set to a second predetermined speed RREF2 that is smaller than the first predetermined speed REF1 so as to match these settings (step 78), and this process is terminated.

  On the other hand, if the answer to step 75 is NO, the gradient flag F_SLP is “3”, and the stop road surface is an uphill gradient, the release end time TBRKOFF is set to a third predetermined time TBRK3 (for example, 0) larger than the second predetermined time TBRK2. 6 sec), the release start time TMOTON is set to a predetermined delay time TDLY (for example, 0.4 sec) (steps 79 and 80). Further, the motor rotational speed ROTOMOT is set to the third predetermined speed RREF3 so as to meet these settings (step 81), and this process is terminated.

  Returning to FIG. 6, after performing the processing of steps 42 to 44 immediately after the start of the restart control, or when not immediately after the restart control, the parking brake 60 release control processing is executed in step 45. Then, the process of FIG.

  FIG. 10 shows the subroutine. In this process, first, in step 91, it is determined whether or not the timer value TMRST of the restart timer reset in step 7 of FIG. 4 is equal to or greater than the release start time TMOTON set in steps 73, 77, or 80 of FIG. Determine. If the answer is NO and the release start time TMOTON has not elapsed since the start of the restart control, in step 92, the motor 65 is maintained in a stopped state.

  On the other hand, when the answer to step 91 is YES, it is determined in step 93 whether or not the timer value TMRST is equal to or greater than the release end time TBRKOFF set in step 72, 76 or 79 of FIG. When this answer is NO and TMOTON ≦ TMRST <TBRKOFF, that is, after the elapsed time from the start of the restart control reaches the release start time TMOTON, until the release end time TBRKOFF reaches FIG. The motor 65 is rotated at the motor rotational speed ROTOMOT set in the step 74, 78 or 81, and this process is terminated.

  On the other hand, if the answer to step 93 is YES and TMRST ≧ TBRKOFF, that is, if the release end time TBRKOFF has elapsed since the start of the restart control, the motor 65 is stopped in step 95 and the process is terminated. To do.

  By the control of the motor 65 as described above, the motor 65 is operated at the timing corresponding to the release start time TMOTON, and the release of the parking brake 60 is started. Thereafter, at a timing corresponding to the release end time TBRKOFF, the motor 65 is stopped and the release of the parking brake 60 is ended.

Returning to FIG. 4, if the answer to step 2 is NO, the idle stop flag F_IDLSTP is “0”, and the engine is not idling stop, it is determined in step 9 whether the restart flag F_RESTART is “1”. To do. If the answer is YES and the control at restart is being performed, it is determined in steps 10 to 12 whether or not the following conditions (a) to (c) are satisfied.
(A) The accelerator opening AP is greater than or equal to a predetermined opening APL (for example, 20 °). (B) The timer value TMRST of the restart timer is greater than or equal to a predetermined time TREF (for example, 1 sec). (C) The vehicle speed VP is predetermined. Speed VREF (for example, 3 km / h) or more

  When none of these conditions (a) to (c) is satisfied, the process proceeds to step 8, the restart control is continued, and the process is terminated.

  On the other hand, when the answer to step 10 is YES and AP ≧ APL, the acceleration request at the start by the driver is high, so that the control at the time of restart should be terminated. The start flag F_RESTART is set to “0”, and the normal control process is executed in step 14 and this process is terminated.

  Further, when either of the answers to the above Steps 11 and 12 is YES and the elapsed time from the start of the control at the time of restart becomes a predetermined time TREF or more, or when the vehicle speed VP becomes the predetermined speed VREF or more, Since it is presumed that the start of the vehicle V has been completed, it is assumed that the control at the time of restarting should be terminated, the steps 13 and 14 are executed, the restart flag F_RESTART is set to “0”, and normal control processing is performed. Execute.

  In addition, after step 13 is executed as described above, the answer to step 9 is NO. In this case, the process proceeds to step 14 and normal control processing is executed.

  In this normal control process, the required torque of the engine 3 is calculated by searching a predetermined map (not shown) according to the accelerator opening AP and the engine speed NE, and the calculated required torque and A fuel injection amount QINJ is calculated according to the engine speed NE. That is, the control of the output of the engine 3 according to the accelerator opening AP is executed.

  FIGS. 11-13 has shown the operation example obtained by the control process of the vehicle V demonstrated so far. FIG. 11 shows an example in which the stop road surface is flat and the inclination angle AOI is in the range of AREFL <AOI <AREFH. In this example, from the state where the vehicle V is traveling, at the time t1, the accelerator pedal opening AP becomes 0 and the brake pedal is depressed, and accordingly, the vehicle speed VP and the engine speed NE are reduced, The braking force FFBRK of the foot brake 50 gradually increases.

  When the stop condition is satisfied (t2), the idle stop flag F_IDLSTP is set to “1”, whereby the idle stop is started (step 4), and the engine speed NE is reduced to zero. Further, in this example, the brake pedal is released immediately before the engine speed NE becomes 0, and the parking brake 60 is operated to compensate for the accompanying decrease in the braking force FFBRK of the foot brake 50 (t3), The braking force FPBRK increases to a certain value.

  Thereafter, when the accelerator pedal is depressed and the accelerator opening AP becomes equal to or larger than the starting opening APST (t4), the restart flag F_RESTART is set to “1” (step 6), the idling stop is completed, and the engine 3 Control at restart is started. At the start of the restart, it is determined that the stop road surface is flat, and the gradient flag F_SLP is set to “2” (step 54).

  Further, according to the determination result of the road surface gradient, the restart target rotational speed NECMDRST is set to the medium second predetermined rotational speed NEREF2 (step 64), and the release end time TBRKOFF is the medium second predetermined predetermined speed. At time TBRK2, the release start time TMOTON is set to 0, and the motor rotation speed ROTOMOT is set to the second predetermined speed RREF2 (steps 76 to 78).

  Then, the fuel injection amount QINJ is calculated in accordance with the set restart target rotational speed NECMDRST, and the fuel is supplied to the engine 3 based on the calculated fuel injection amount QINJ. 2 Increases toward a predetermined rotational speed NEREF2. Further, when the release start time TMOTON is set to 0, the motor 65 of the parking brake 60 starts to rotate at the second predetermined speed RREF2 simultaneously with the start of the restart control, and the braking force FPBRK decreases accordingly.

  When the release end time TBRKOFF (= second predetermined time TBRK2) has elapsed from the start of the restart control (t5), the brake pad 64b of the parking brake 60 is pulled away from the disc 51, whereby the braking force FPBRK Becomes zero, the braking by the parking brake 60 is released, and the vehicle speed VP starts to increase from zero.

  Thereafter, when the vehicle speed VP reaches the predetermined speed VREF (t6), the restart flag F_RESTART is set to “0” (step 13), the control at the time of restart ends, and the normal control is started. In this normal control, the fuel injection amount QINJ is calculated according to the accelerator opening AP and the engine speed NE.

  FIG. 12 is an example in which the stop road surface has a downward slope and the inclination angle AOI ≦ AREFL. In this example, the operation at time points t11 to t14 is basically the same as the example of FIG. 11 described above. When the restart control of the engine 3 is started at the time point 14, it is determined that the stop road surface is a downward slope at that time, and the gradient flag F_SLP is set to “1” (step 52).

  Further, according to the determination result of the road surface gradient, the restart target rotational speed NECMDRST is set to a smaller first predetermined rotational speed NEREF1 (step 62), and the release end time TBRKOFF is smaller than the first predetermined time TBRK1. Further, the release start time TMOTON is set to 0, and the motor rotational speed ROTOMOT is set to a larger first predetermined speed RREF1 (steps 72 to 74).

  Then, restart is started by supplying fuel to the engine 3 based on the fuel injection amount QINJ calculated according to the target rotational speed NECMDRST at restart, and the engine rotational speed NE is set to the first predetermined rotational speed NEREF1. Ascend towards. Further, by setting the release start time TMOTON to 0, the motor 65 of the parking brake 60 starts to rotate at the first predetermined speed RREF1 simultaneously with the start of the restart control, and the braking force FPBRK decreases accordingly.

  When the release end time TBRKOFF (= first predetermined time TBRK1) has elapsed since the start of the restart control (t15), the braking force FPBRK becomes 0, the braking by the parking brake 60 is released, The vehicle speed VP starts to increase from zero.

  Thereafter, when the vehicle speed VP reaches the predetermined speed VREF (t16), the restart flag F_RESTART is set to “0” (step 13), the control at the time of restarting is ended, and the normal control is started.

  FIG. 13 shows an example in which the stop road surface is uphill and the inclination angle AOI ≧ AREFH. In this example, the operation from the time point t21 to t24 is basically the same as the example of FIGS. 11 and 12 described above. When the restart control of the engine 3 is started at the time point 24, at that time, it is determined that the stop road surface is an upward gradient, and the gradient flag F_SLP is set to “3” (step 55).

  Further, the restart target rotational speed NECMDRST is set to a third predetermined rotational speed NEREF3 larger than the second predetermined rotational speed NEREF2 according to the determination result of the road surface gradient (step 65), and the release end time TBRKOFF is set. At a third predetermined time TBRK3 larger than the second predetermined time TBRK2, the release start time TMOTON is set to a predetermined delay time TDLY, and the motor rotation speed ROTMOT is set to a third predetermined speed RREF3 (steps 79 to 81).

  Then, based on the fuel injection amount QINJ calculated according to the restart target rotational speed NECMDRST, the fuel is supplied to the engine 3 to start the restart, and the engine rotational speed NE is set to the third predetermined rotational speed NEREF3. Ascend towards. Further, when the delay time TDLY has elapsed from the start of the restart control (t24a), the motor 65 of the parking brake 60 starts to rotate at the third predetermined speed RREF3, and accordingly, the braking force FPBRK decreases.

  When the release end time TBRKOFF (= third predetermined time TBRK3) has elapsed from the start of the restart control (t25), the braking force FPBRK becomes 0, the braking by the parking brake 60 is released, The vehicle speed VP starts to increase from zero.

  Thereafter, when the vehicle speed VP reaches the predetermined speed VREF (t26), the restart flag F_RESTART is set to “0” (step 13), the control at the time of restarting is terminated, and the normal control is started.

  In the above three examples, when the vehicle speed VP reaches the predetermined speed VREF, the control at the time of restart is shifted to the normal control, but before that, the accelerator opening AP becomes equal to or higher than the predetermined opening APL. If the timer value TMRST of the restart timer is equal to or longer than the predetermined time TREF (step 11: YES), the shift to the normal control is performed at that time.

  As described above, according to the present embodiment, when the accelerator opening AP becomes equal to or larger than the starting opening APST during the idle stop, the idle stop is terminated and the engine is restarted. Therefore, even if the brake pedal is released during idling stop, the idling stop is continued as long as the accelerator pedal is not depressed. can do. Further, braking of the vehicle V during that time is secured by the parking brake 60.

  Further, when it is determined that the road surface on which the vehicle V has stopped during the idle stop is a downward slope, the release end time TBRKOFF is set to a first predetermined time smaller than that when the road surface is flat (= second predetermined time TBRK2). Since TBRK1 is set, dragging of the parking brake 60 can be avoided and fuel consumption can be improved. In addition, the target rotational speed NECMDRST at the time of restart is set to the first predetermined rotational speed NEREF1 smaller than when the road surface is flat (= second predetermined rotational speed NEREF2), so that sudden start due to excessive output is prevented. However, it is possible to smoothly start the vehicle V on a downward slope and to further improve fuel consumption.

  Further, when the inclination angle AOI is equal to or greater than the second predetermined angle AREFH, it is determined that the road surface slope is an upward slope, and the release end time TBRKOFF is set to a third predetermined time TBRK3 that is larger than the value when the road surface is flat. Since the setting is made, the parking brake 60 can be released after the output of the engine 3 rises, and the vehicle V can be prevented from retreating at the start. In addition, since the restart target rotational speed NECMDRST is set to the third predetermined rotational speed NEREF3 that is larger than the value when the road surface is flat, the output of the engine 3 can be further increased, and the start It is possible to smoothly start the vehicle on an ascending slope while preventing time lag.

  Also, when the elapsed time TMRST from the start of the restart control is equal to or greater than the predetermined time TREF, when the vehicle speed VP is equal to or greater than the predetermined speed VREF, or when the accelerator opening AP is equal to or greater than the predetermined opening APL, Since the control is shifted to normal control and the output of the engine 3 is controlled in accordance with the accelerator pedal opening AP, the vehicle V can be started while satisfactorily responding to the driver's acceleration request, and drivability is improved. Can do.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the inclination angle AOI is used to determine whether the slope of the road surface is a downward slope, a flat slope, or an upward slope, and the target rotational speed NECMDRST at the restart and the release are determined according to the determination result Although the end time TBRKOFF is set in steps, the present invention is not limited to this, and the restart target rotational speed NECMDRST and the release end time TBRKOFF may be set continuously according to the inclination angle AOI.

  In the embodiment, the vehicle V is controlled to be braked by operating the parking brake 60 when the idle stop condition is satisfied. However, the present invention is not limited to this. For example, the brake pedal is automatically activated. A device that can be operated may be provided, and the vehicle V may be controlled to be braked by operating the device when the idle stop condition is satisfied. In that case, after the end of the idle stop, the brake pedal is automatically released according to the release end time TBRKOFF.

  The embodiment is an example in which the present invention is applied to a vehicle equipped with a gasoline engine. However, the present invention is not limited to this, and the present invention is also applied to a vehicle equipped with various engines such as a diesel engine other than a gasoline engine. Is possible. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Stop control apparatus 2 ECU (Restart condition determination means, target rotational speed setting means, output control means,
Brake release timing setting means)
3 Internal combustion engine 22 Vehicle speed sensor (vehicle speed detection means)
23 Accelerator opening sensor (Accelerator opening detecting means)
25 Inclination angle sensor (gradient detection means)
60 Parking brake (braking device)
V vehicle
AOI angle of inclination (gradient of the road surface where the vehicle is stopped)
NECMDRST Target speed at restart
NE engine speed (speed of internal combustion engine)
QINJ Fuel injection amount (output of internal combustion engine)
TBRKOFF release end time (braking release timing)
VP vehicle speed (vehicle speed)

Claims (2)

The internal combustion engine is stopped when a predetermined stop condition is satisfied, restarted when a predetermined restart condition is satisfied, and the vehicle is operated by operating a braking device when the stop condition is satisfied. A vehicle stop control device for controlling to brake,
Restart condition determining means for determining that the restart condition is satisfied when the accelerator pedal is depressed;
Slope detecting means for detecting the slope of the road surface on which the vehicle is stopped;
Target rotational speed setting means for setting a target rotational speed at restart at the time of restarting the internal combustion engine according to the detected road surface gradient;
The output of the internal combustion engine is set so that the rotational speed of the internal combustion engine does not become the rotational speed that becomes the output of the internal combustion engine according to the operation of the accelerator pedal, but the set target rotational speed at the time of restart. Output control means for controlling,
Brake release timing setting means for setting a brake release timing for releasing the braking of the braking device after the restart condition is satisfied according to the gradient of the road surface;
Equipped with a,
When the detected slope of the road surface is a downward slope, compared to when it is flat,
The target rotational speed setting means sets the restart target rotational speed to a smaller value,
The brake release timing setting means sets the brake release timing to an earlier timing,
When the detected slope of the road surface is an upward slope, compared to when it is flat,
The target rotational speed setting means sets the restart target rotational speed to a larger value,
The vehicle brake stop control device, wherein the brake release timing setting means sets the brake release timing to a later timing . Vehicle speed detection means for detecting the speed of the vehicle;
An accelerator opening detecting means for detecting the opening of the accelerator pedal, and
The output control means, when the restart condition is satisfied, when the elapsed time is equal to or longer than a predetermined time, when the detected vehicle speed is equal to or higher than a predetermined speed, or when the detected opening of the accelerator pedal is detected. 2. The vehicle stop control device according to claim 1, wherein an output of the internal combustion engine is controlled in accordance with an opening degree of the accelerator pedal when is equal to or greater than a predetermined opening degree .

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