JP5677406B2 - Automatic stop / start control device for internal combustion engine - Google Patents

Description

  The present invention is applied to a vehicle that transmits the rotational force of the output shaft of an internal combustion engine to driving wheels, and performs automatic stop processing of the internal combustion engine when a predetermined internal combustion engine stop condition is satisfied, and the predetermined restart condition is satisfied. The present invention relates to an automatic stop / start control device for an internal combustion engine, which performs restart control of the internal combustion engine in the case where the engine is restarted.

  Some vehicles that use an internal combustion engine as a drive source perform automatic stop control (idle stop control) of the internal combustion engine from the viewpoint of reducing fuel consumption (fuel consumption) and environmental load. The idle stop control is a control for automatically stopping the internal combustion engine when a predetermined stop condition is satisfied during the idling operation of the internal combustion engine and restarting the internal combustion engine when a predetermined restart condition is satisfied.

  However, when the internal combustion engine is automatically stopped or restarted by the idle stop control as described above, the rotation of the output shaft of the internal combustion engine changes, so that the driving force applied to the drive wheels of the vehicle can change. . In this case, due to the change in the driving force, the driving force and braking force of the vehicle due to brake control and traction control cannot be adjusted appropriately, and drivability may be reduced.

  Therefore, conventionally, when the brake control and traction control described above are performed, the situation in which the driving force applied to the driving wheels of the vehicle changes is avoided by prohibiting the automatic stop processing and restart processing of the internal combustion engine. However, a technique for suppressing drivability deterioration has been proposed.

  Further, as shown in Patent Document 1, for example, a vehicle that performs idling stop control during traveling, in which the condition that the traveling speed of the vehicle falls below a predetermined speed (for example, 20 km / h) higher than 0 is included in the automatic stop condition of the internal combustion engine. Has also been proposed. According to such running idle stop control, it is possible to expand the operating range in which the internal combustion engine is automatically stopped, and to further improve the fuel consumption reduction effect of the internal combustion engine.

  However, if the internal combustion engine is stopped or restarted while the vehicle is running, the rotational force of the output shaft of the internal combustion engine is transmitted to the drive wheels, which may cause the rotational speed of the drive wheels to change rapidly. is there. In this case, the driving wheel slips or locks, so that the steering stability of the vehicle is lowered and drivability may be lowered. In particular, low friction coefficient roads (so-called low μ roads) such as frozen road surfaces with relatively low road surface friction coefficients and bad roads (unevenness or poor road surface conditions make it difficult for the vehicle to travel). In a situation where the vehicle is traveling on a road, the same applies hereinafter), if the internal combustion engine is stopped or restarted while traveling, slipping or locking of the drive wheels due to the vehicle tends to occur.

  In this regard, in the control device described in Patent Document 1, in a vehicle capable of idling stop during traveling, when the wheel slip is likely to occur based on the detected steering angle and vehicle speed of the vehicle, the internal combustion engine is stopped / restarted. The restriction is imposed on at least one of the starting. Specifically, the slip of the drive wheel at the time of re-start is suppressed by suppressing the rising of the torque transmitted to the drive wheel when the internal combustion engine is restarted.

JP 2010-285961 A

  However, in the prior art described in Patent Document 1, a situation in which wheel slip can occur is determined based on the detected steering angle and vehicle speed of the vehicle, and a limit is imposed on the stop or restart of the running internal combustion engine. . For this reason, even in a region (situation) where wheel slip does not actually occur, idle stop during traveling and idle stop when stopped are prohibited. Further, the internal combustion engine is restarted and returned in a situation not intended by the driver of the vehicle. As a result, it may not be possible to achieve both good driving performance of the vehicle (to ensure driving merchantability) and prevention of deterioration of fuel consumption of the vehicle.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to ensure both good driving performance of the vehicle (ensurement of driving merchandise) and prevention of deterioration of fuel consumption of the vehicle. An object of the present invention is to provide an automatic stop / start control device for an internal combustion engine.

In order to solve the above problems, an automatic stop / start control device for an internal combustion engine according to the present invention is applied to a vehicle that transmits a rotational force of an output shaft of an internal combustion engine (3) to a drive wheel (DW), and has a predetermined internal combustion engine. In an automatic stop / start control apparatus for an internal combustion engine that performs an automatic stop process of the internal combustion engine (3) when an engine stop condition is satisfied and performs a restart process of the internal combustion engine (3) when a predetermined restart condition is satisfied A control means (2) for controlling the automatic stop process and restart process of the internal combustion engine (3), and a road surface condition determination means (2) for determining the condition of the road surface on which the vehicle is traveling, As a control mode related to the automatic stop of the internal combustion engine (3) by the control means (2), an automatic stop permission mode during travel for permitting automatic stop of the internal combustion engine (3) during travel of the vehicle, and an internal combustion engine during travel of the vehicle. Disallowing automatic stop of engine (3) And to include an automatic stop prohibition mode traveling to allow automatic stop of the internal combustion engine (3) only when the vehicle is stopped, while the vehicle is running, the status of road surface at the discretion of the road conditions by road state determining means when the low friction coefficient road or rough road is the effect that the decision has been made to change the travel automatically stopped disallowed mode control mode to an automatic stop from running during the automatic stop permission mode of the internal combustion engine, then the vehicle once If it is determined that the road surface condition has returned from the low friction coefficient road or the rough road to the normal road surface after the vehicle has stopped once until the vehicle stops , Control is performed to return the control mode relating to automatic stop of the internal combustion engine from the automatic stop disapproval mode during travel to the automatic stop permit mode during travel.

  In the internal combustion engine automatic stop / start control apparatus according to the present invention, while it is determined that the road surface on which the vehicle is traveling is a low friction coefficient road or a bad road, the control relating to the automatic stop of the internal combustion engine is performed. The mode is changed to an automatic stop non-permission mode in which the automatic stop of the internal combustion engine is not permitted during traveling. As a result, the automatic stop of the running internal combustion engine is disallowed only when it is determined that the vehicle is actually traveling on a low friction coefficient road such as a frozen road surface or a rough road with many irregularities (idle stop). Therefore, it is possible to ensure good running performance of the vehicle (to ensure traveling merchandise) and to effectively prevent deterioration in fuel consumption of the vehicle.

  Furthermore, when it is determined that the road surface condition has returned from the low friction coefficient road or the rough road to the normal road surface, the control mode relating to the automatic stop of the internal combustion engine is changed from the automatic stop prohibition mode during travel to the automatic stop during travel. Control to return to the permission mode is performed. That is, even when the control mode related to the automatic stop of the internal combustion engine is changed to the automatic stop non-permission mode, the switching to the automatic stop permission mode can be performed again by performing the return judgment from the low friction coefficient road or the bad road. It becomes possible. Thereby, the further improvement of the fuel consumption of a vehicle can be aimed at, ensuring the favorable running performance of a vehicle.

  The automatic stop / start control device for an internal combustion engine includes a wheel speed sensor (75) for detecting the rotational speed of each wheel of the vehicle, and the road surface condition judging means is based on the detection value of the wheel speed sensor (75). A skid running state in which the driving wheel (DW) is idling when the vehicle is accelerating or a locked running state in which the driving wheel (DW) is in a rotation stopped state when the vehicle is decelerating is detected, and the skid running state or the locked running state is the first. When it is detected that the time (T1) has continued, it is determined that the road surface condition is a low friction coefficient road, the skid running state or the locked running state is not detected for the second time (T2), and When it is detected that the vehicle has stopped once, it may be determined that the road surface condition has returned from the low friction coefficient road to the normal road surface.

  According to this configuration, since the traveling of the low friction coefficient road is detected according to the duration of the skid traveling state or the locked traveling state based on the detection value of the wheel speed sensor, the road surface on which the vehicle is traveling is the low friction coefficient road. Can be appropriately determined. In addition, even when the low friction coefficient road is detected and the automatic stop prohibition mode during travel is set, it is possible to return from the automatic stop prohibition mode during travel to the automatic stop permit mode during travel with the vehicle stop condition as an essential condition. . Thereby, the fuel consumption deterioration of a vehicle can be prevented effectively. In addition, since the automatic stop non-permission mode during traveling can be continued until the vehicle is stopped, it is possible to ensure good traveling performance of the vehicle.

  Furthermore, in this case, the second time (T2) may be set longer than the first time (T1). Thus, by setting the second time to be longer than the first time, it is possible to return from the traveling automatic stop disapproval mode to the traveling automatic stop permission mode in a longer time. Accordingly, it is possible to more reliably return to the automatic stop permission mode during traveling.

  The automatic stop / start control device for an internal combustion engine includes vehicle speed detecting means (73) for detecting the vehicle speed and accelerator opening detecting means (72) for detecting the accelerator opening, and the road surface condition determining means includes: The vehicle speed detected by the vehicle speed detecting means (73) is within a predetermined speed range (V1 ≦ V ≦ V2), and the accelerator opening (AP) detected by the accelerator opening detecting means (72) is a predetermined opening (AP1 ≦ AP ≦ AP2), the accelerator opening change rate (ΔAP) detected by the accelerator opening detecting means (72) is within a predetermined change rate (ΔAP ≦ ΔAP1), and the vehicle speed detecting means (73 ) When the vehicle acceleration / deceleration (ΔG) based on the detected vehicle speed exceeds a predetermined darkness value (ΔG1) is detected a predetermined number of times (N) or more during the third time (T3). , Make a decision that the road surface is bad When the vehicle acceleration / deceleration (ΔG) does not change beyond the predetermined threshold (ΔG1) over the predetermined number of times (N) during the fourth time (T4), it is detected that the vehicle has stopped once. In this case, it may be determined that the road surface condition has returned from a bad road to a normal road surface.

  According to this configuration, since it is detected that the rough road is traveling based on the vehicle speed, the accelerator opening, and the rate of change thereof, it is possible to appropriately determine that the road surface on which the vehicle is traveling is a rough road. Further, when a rough road is detected and the automatic stop prohibition mode during travel is set, it is possible to return to the automatic stop permission mode during travel from the automatic stop prohibition mode during travel with the vehicle stop condition as an essential condition. Thereby, the fuel consumption deterioration of a vehicle can be prevented effectively. In addition, since the automatic stop non-permission mode during traveling can be continued until the vehicle is stopped, it is possible to ensure good traveling performance of the vehicle.

  In this case, the fourth time (T4) may be set longer than the third time (T3). Thus, by setting the fourth time to be longer than the third time, it is possible to return from the traveling automatic stop disapproval mode to the traveling automatic stop permission mode in a longer time. Accordingly, it is possible to more reliably return to the automatic stop permission mode during traveling.

  In the automatic stop / start control apparatus for an internal combustion engine, a continuously variable transmission mechanism (6) for shifting and outputting the rotation of the internal combustion engine (3), and a rotation changed by the transmission mechanism (6) for driving wheels ( And an output shaft (25) for output to the DW) side, and the road surface state determination by the road surface state determination means is a detection by detecting a value from the rotation output from the output shaft (25) to the drive wheel (DW) side. It may be performed based on the value. In this case, the continuously variable transmission mechanism may be a belt-type continuously variable transmission mechanism (6).

  According to this, the road surface condition during the traveling of the vehicle is performed based on the detected value obtained by detecting the rotation value output from the output shaft of the continuously variable transmission mechanism to the drive wheel side. It is possible to detect the road surface condition more accurately. Further, when the continuously variable transmission mechanism is a belt-type continuously variable transmission mechanism, it is possible to effectively prevent belt slip by detecting the road surface condition where the vehicle is traveling more accurately. Thus, it is possible to effectively protect each part of the transmission mechanism.

  In addition, the code | symbol in said parenthesis shows the code | symbol of the component in embodiment mentioned later as an example of this invention.

  According to the automatic stop / start control apparatus for an internal combustion engine according to the present invention, the automatic stop of the running internal combustion engine is disabled only while it is determined that the vehicle is actually traveling on a low friction coefficient road or a bad road. In addition, by making a judgment of return from a low friction coefficient road or a bad road, the automatic stop of the running internal combustion engine is permitted again, thereby ensuring good running performance of the vehicle (running Ensuring product quality) and preventing deterioration of the fuel consumption of the vehicle.

1 is a skeleton diagram showing a drive system of a vehicle provided with an automatic stop / start control device for an internal combustion engine according to an embodiment of the present invention. It is a block diagram of ECU which performs automatic stop control of an internal combustion engine. It is a table | surface for demonstrating the judgment conditions and cancellation | release conditions of a low friction coefficient path. It is a table | surface for demonstrating the bad road judgment conditions and cancellation conditions. It is a flowchart which shows the determination procedure of idle stop permission during driving | running | working. It is a flowchart which shows the determination procedure of a low friction coefficient path. It is a timing chart which shows the time change of each value in the case of carrying out running idle stop control. It is a timing chart which shows the time change of each value at the time of implementing another mode of running idle stop control. It is a timing chart which shows the time change of each value when not performing idle stop control during driving.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The vehicle drive system shown in FIG. 1 transmits an internal combustion engine (hereinafter referred to as “engine”) 3 as a power source of the vehicle and the driving force of the engine 3 to the left and right drive wheels DW (only the right drive wheel is shown). Torque converter 4, forward / reverse switching mechanism 5 and continuously variable transmission (CVT) 6. The engine 3 is a gasoline engine and has a crankshaft 3a for outputting driving force.

  The torque converter 4 includes a pump impeller 4a, a turbine runner 4b, and a lockup clutch 4c. The pump impeller 4a is connected to the crankshaft 3a, and the turbine runner 4b is connected to an input shaft 14 to be described later, and hydraulic oil is filled between the both 4a and 4b. The driving force of the engine 3 (hereinafter referred to as “engine driving force”) is basically transmitted to the input shaft 14 via the pump impeller 4a, hydraulic oil, and the turbine runner 4b.

  The forward / reverse switching mechanism 5 includes a planetary gear unit 11, a forward clutch 12, and a reverse brake 13. The planetary gear unit 11 is of a single pinion type, and supports a sun gear 11a, a ring gear 11b, a plurality of planetary gears 11c (only two are shown) meshing with both gears 11a and 11b, and these planetary gears 11c are rotatably supported. Carrier 11d. The sun gear 11 a is provided integrally with the input shaft 14.

  The forward clutch 12 is a hydraulic type, and its inner is integrally attached to the input shaft 14, and the outer of the forward clutch 12 is integrally attached to the ring gear 11 b and the main shaft 21. The main shaft 21 is formed in a hollow shape, and the input shaft 14 is rotatably disposed inside the main shaft 21. By engaging the forward clutch 12, the input shaft 14 is directly connected to the main shaft 21, and by releasing the forward clutch 12, differential rotation between the input shaft 14 and the main shaft 21 is allowed. The reverse brake 13 is composed of a hydraulic clutch or the like and is attached to the carrier 11d. The reverse brake 13 holds the carrier 11d in a non-rotatable state when in the engaged state, and rotates the carrier 11d when in the released state. Allow.

  In the forward / reverse switching mechanism 5 configured as described above, when the vehicle moves forward, the forward clutch 12 is engaged and the reverse brake 13 is released. As a result, the main shaft 21 rotates at the same rotational speed in the same direction as the input shaft 14. On the other hand, when the vehicle moves backward, the forward clutch 12 is released and the reverse brake 13 is engaged. Thereby, the main shaft 21 rotates in the opposite direction to the input shaft 14.

  The continuously variable transmission 6 is a belt type and includes the main shaft 21, the input pulley 22, the output pulley 23, the transmission belt 24, and the auxiliary shaft 25. The input pulley 22 has a movable part 22a and a fixed part 22b facing each other. The movable portion 22 a is attached to the main shaft 21 so as to be movable in the axial direction and relatively non-rotatable, and the fixed portion 22 b is fixed to the main shaft 21. A V-shaped belt groove for winding the transmission belt 24 is formed between the two 22a and 22b. Further, the movable portion 22a is provided with a DR oil chamber (not shown), and when the hydraulic pressure is supplied to the DR oil chamber, the movable portion 22a moves in the axial direction, whereby the input pulley 22 is provided. The pulley width is changed and its effective diameter changes.

  The output pulley 23 is configured in the same manner as the input pulley 22. The movable portion 23 a is attached to the auxiliary shaft 25 so as to be movable and non-rotatable in the axial direction, and the fixed portion 23 b is connected to the auxiliary pulley 25. It is fixed to the shaft 25. A V-shaped belt groove is formed between the two 23a and 23b. The movable part 23a is provided with a DN oil chamber (not shown) and a return spring 23d. By supplying hydraulic pressure to the DN oil chamber, the movable portion 23a moves in the axial direction, whereby the pulley width of the output pulley 23 is changed and the effective diameter thereof is changed. Further, the return spring 23d biases the movable portion 23a toward the fixed portion 23b, that is, toward the side that expands the DN oil chamber. The transmission belt 24 is wound around the pulleys 22 and 23 while being fitted in the belt grooves of the pulleys 22 and 23.

  As described above, in the continuously variable transmission 6, the effective diameters of the pulleys 22 and 23 are changed steplessly by supplying hydraulic pressure to the DR oil chamber of the input pulley 22 and the DN oil chamber of the output pulley 23. Thus, the gear ratio is controlled steplessly. This gear ratio is a ratio between the rotational speed of the input pulley 22 and the rotational speed of the output pulley 23.

  A gear 25a is fixed to the auxiliary shaft 25, and the gear 25a meshes with the gear G of the differential gear mechanism DF via large and small idler gears IG1 and IG2 provided integrally with the idler shaft IS. ing. The differential gear mechanism DF is connected to the left and right drive wheels DW.

  In the drive system having the above configuration, the engine driving force is transmitted to the left and right drive wheels DW via the torque converter 4, the forward / reverse switching mechanism 5, the continuously variable transmission 6, and the differential gear mechanism DF. At that time, the forward / reverse switching mechanism 5 switches the rotation direction of the transmitted driving force between the forward rotation direction and the reverse rotation direction, thereby moving the vehicle forward and backward. The engine driving force is transmitted to the drive wheels DW in a state where the engine driving force is continuously changed by the continuously variable transmission 6.

  Further, as shown in FIG. 2, an ECU (control means) 2 for controlling the engine 3 and the transmission 6 is mounted on the vehicle. The ECU 2 is composed of a microcomputer including an I / O interface, CPU, RAM, ROM, and the like. A detection signal representing the number of revolutions of the engine 3 is output from the engine revolution number sensor 71 to the ECU 2. Further, the ECU 2 outputs a detection signal representing an operation amount (hereinafter referred to as “accelerator opening”) of an accelerator pedal (not shown) of the vehicle from the accelerator opening sensor 72. Further, a detection signal representing the vehicle speed of the vehicle is output from the vehicle speed sensor 73. The brake sensor 74 outputs a detection signal for a brake operation (a brake pedal depression amount). Further, a wheel speed sensor 75 that detects the wheel speed of each of the four wheels outputs a detection signal for the wheel speed of each of the four wheels. Further, a vehicle acceleration / deceleration detection signal is output from the acceleration / deceleration sensor (G sensor) 76. Although not shown, a shift position sensor that detects the shift position of the AT, a steering angle sensor that detects the steering angle of the steering wheel, an outside air temperature sensor that detects the outside air temperature, and the like are also provided.

  The ECU 2 controls the operation of the engine 3 according to the control program stored in the ROM in accordance with the detection signals from the various sensors 71 to 76 described above. In particular, the ECU 2 performs idle stop control (automatic stop control) of the engine 3. The idle stop control is to automatically stop the engine 3 when a predetermined stop condition is satisfied during operation of the engine 3, and then restart the engine 3 when a predetermined restart condition is satisfied. Thereby, the fuel consumption reduction effect of the engine 3 can be obtained. Further, here, the stop condition of the engine 3 is assumed to be a case where a brake operation is performed and a case where the traveling speed of the vehicle is lower than a predetermined speed (for example, 20 km / h) higher than zero. Thereby, the engine 3 is automatically stopped even before the vehicle stops, and the operation range in which the engine 3 is automatically stopped can be expanded as compared with the case where the idle stop control of the engine 3 is permitted only when the vehicle is stopped. It becomes possible. Thereby, it becomes possible to improve the fuel consumption reduction effect.

  Here, the specific content of the idle stop control of the engine 3 by the vehicle of this embodiment is demonstrated in detail. In the idle stop control of the engine 3 by the vehicle according to the present embodiment, as the control mode, a running idle stop permission mode for allowing the engine 3 to idle idle while the vehicle is traveling, and an idle stop of the engine 3 while the vehicle is traveling are set. A running idle stop non-permission mode is included. Specifically, in the idle stop control of the engine 3, the following controls (1) to (4) are performed.

(1) When it is determined that the road surface on which the vehicle is traveling is a low friction coefficient road (low μ road) or a rough road, the idle stop during traveling is prohibited as a control mode related to the idle stop control of the engine 3. Set the idle stop prohibit mode while driving.
(2) After setting the idle stop prohibition mode during traveling by detecting the traveling on the low friction coefficient road or the rough road from when the vehicle starts to travel until it stops, then until the vehicle stops once Continue to set the idle stop prohibit mode while driving.
(3) Whether the road surface on which the vehicle is traveling is a low friction coefficient road is determined by comparing the front wheel speed and the rear wheel speed based on the detection value of the wheel speed sensor 75, This is done by judging the front wheel lock state.
(4) Judgment whether the road surface on which the vehicle is traveling is a rough road is based on the detected value of the acceleration / deceleration sensor (G sensor) 76 based on the acceleration / deceleration variation (G variation) applied to the traveling vehicle. This is done by monitoring and counting the number of fluctuations in acceleration / deceleration within a predetermined time.

FIG. 3 is a table for explaining the judgment condition and the release condition of the low friction coefficient road (low μ road). In the wheel skid determination and lock determination, the wheel speed difference ΔV is calculated based on the wheel speeds of the four wheels detected by the wheel speed sensor 75. The wheel speed difference ΔV is calculated by the following equation (1).
Wheel speed difference ΔV = (Average front wheel speed Vf) − (Rear average wheel speed Vr) (Formula 1)

  When the driving force from the engine 3 is transmitted to the front wheels (driving wheels) and the vehicle is accelerating, the wheel speed difference ΔV is greater than or equal to a predetermined value ΔV1 (ΔV ≧ ΔV1). It is determined that the (drive wheel) skid state. As a specific example in this case, when the vehicle is traveling on a road that includes both a non-frozen road surface and a frozen road surface, the grip force of the front wheel is increased when the road surface that the front wheel steps on changes from the frozen road surface to the non-frozen road surface. It increases rapidly and the average wheel speed Vf drops to a value close to zero. Thereby, the value of the wheel speed difference ΔV becomes equal to or greater than the predetermined value ΔV1.

  On the other hand, when the braking speed by the brake is applied to the front wheels (driving wheels) and the vehicle is decelerating, if the wheel speed difference ΔV is less than or equal to another predetermined value ΔV2 (ΔV ≦ ΔV2), the front wheels It is determined that the (driving wheel) is locked. As a specific example in this case, when the vehicle is traveling on a road including both a non-frozen road surface and a frozen road surface, the braking force applied by the brake is applied to the front wheels (the brake pedal is stepped on) ), When the road surface on which the front wheels are stepped changes from the non-freezing road surface to the frozen road surface, the grip force of the front wheels rapidly decreases, and the braking force by the brake exceeds the grip force from the road surface. At that time, the front wheel average wheel speed Vf instantaneously becomes 0 or a value very close to 0, so that the value of the wheel speed difference ΔV becomes a predetermined value ΔV2 or less.

  In addition, although the case where the vehicle is a front wheel drive vehicle (when the front wheel is a drive wheel) is described here, when the vehicle is a rear wheel drive vehicle, the rear wheel is a drive wheel, and the four wheel drive vehicle In this case, the front and rear wheels are drive wheels.

  The determination condition (low friction coefficient road determination flag Fa = 0 → 1) that the road surface on which the vehicle is traveling is a low friction coefficient road (low μ road) is as follows: Based on. (A) The front wheel is skid. (B) The four wheels are skid. (C) The front wheel is locked. When any of these (a) to (c) continues for a predetermined time (first time) T1 or more, it is determined that the vehicle is traveling on the low friction coefficient road. Note that the predetermined time (first time) T1 can be, for example, T1 = 0.05 (sec).

  On the other hand, the low friction coefficient path determination cancellation condition (low friction coefficient path determination flag Fa = 1 → 0) is performed based on the following (d) to (f). (D) The front wheels are not skid. (E) The four wheels are not skid. (F) The front wheels are not locked. When all of these (d) to (f) continue for time T2 or more, and when the vehicle has stopped once, it is determined that the vehicle is not already traveling on the low friction coefficient road, and the low friction coefficient road determination is canceled. . In addition, said time T2 can be set to T2 = 1.0 (sec) as an example.

  FIG. 4 is a table for explaining rough road determination conditions and cancellation conditions. As shown in the table of FIG. 6, the rough road determination condition (rough road determination flag Fb = 0 → 1) is performed based on the following (g) and (h). That is, when both (g) and (h) are established, it is determined that the vehicle is traveling on a rough road.

(G) It is in a state where it can be determined that the vehicle is traveling on a rough road. Specifically, the vehicle speed V detected by the vehicle speed sensor 73 is within a predetermined range (V1 ≦ V ≦ V2), and the accelerator opening AP detected by the accelerator opening sensor 72 is equal to or less than the predetermined opening AP1 (AP ≦ AP1). ) And the change amount ΔAP of the accelerator opening AP is equal to or less than the predetermined change amount ΔAP1 (ΔAP ≦ ΔAP1). Here, V1 is V1 = 10 (km / h) as an example, V2 is V2 = 70 (km / h) as an example, AP1 is AP1 = 4/8 as an example, and ΔAP1 is ΔAP1 as an example. = 0.4 / 8.

(H) The rate of change in acceleration / deceleration (G fluctuation) ΔG of the vehicle exceeds a predetermined value ΔG1 (ΔG ≧ ΔG1) is N or more predetermined times within a predetermined time (third time) T3. Here, ΔG1 is, for example, ΔG1 = 0.4G, the predetermined time (third time) T3 is, for example, T3 = 5 (sec), and the predetermined number N is, for example, N = 60 (times). Can do.

  On the other hand, the rough road determination cancellation condition (rough road determination flag Fb = 1 → 0) is (i) a predetermined time (fourth time) T4 after the vehicle is determined not to travel on the rough road. After the lapse of time and when the vehicle stops once, the rough road judgment is canceled. The predetermined time (fourth time) T4 here may be T4 = 30 (sec) as an example.

  FIG. 5 is a flowchart showing a procedure of the idling stop permission determination during traveling in the idling stop control during traveling. In the running idle stop permission determination, first, it is determined whether or not the vehicle brake is on (step ST1-1). Whether the brake is on is determined based on the detection value of the brake sensor 74. As a result, if the brake is not on (NO), that is, if the brake is in an inoperative state, it is determined whether or not idle stop is prohibited (prohibited) during travel (step ST1-2). On the other hand, if the brake is on (YES), it is subsequently determined whether or not the accelerator is off (step ST1-3). Whether or not the accelerator is off is determined based on the detection value of the accelerator opening sensor 72. As a result, if the accelerator is not off (NO), that is, if the accelerator is on, it is determined whether or not the vehicle is idle stopped (step ST1-2). On the other hand, if the accelerator is off (YES), it is determined whether or not the vehicle is traveling on a low friction coefficient road (step ST1-4). As a result, when it is determined that the vehicle is traveling on a low friction coefficient road (YES), it is determined to prohibit idling stop during traveling (step ST1-2). On the other hand, when it is determined that the vehicle is not traveling on the low friction coefficient road (NO), it is subsequently determined whether the vehicle is traveling on a bad road (step ST1-5). As a result, when it is determined that the vehicle is traveling on a rough road (YES), it is determined to prohibit idling stop during traveling (step ST1-2). On the other hand, when it is determined that the vehicle is not traveling on a rough road (NO), it is determined whether or not idle stop is permitted during traveling (step ST1-6).

  FIG. 6 is a flowchart showing a low-friction coefficient road determination procedure for determining whether or not the vehicle is traveling on a low-friction coefficient road. In this low friction coefficient road determination, it is determined whether or not the road surface on which the vehicle is currently traveling is a low friction coefficient road (low μ road) (step ST2-1). As a result, when it is determined that the road surface on which the vehicle is currently traveling is a low friction coefficient road (YES), it is subsequently determined whether or not the vehicle has stopped once (step ST2-2). As a result, if the vehicle has not stopped once (NO), the determination that it is a low friction coefficient road (low μ road) is continued (step ST2-3), and if the vehicle has stopped once (YES). Then, the determination that the road is a low friction coefficient road is canceled, and the determination that the road is a normal road surface is made (step ST2-4).

  On the other hand, if it is determined in step ST2-1 that the road surface on which the vehicle is currently traveling is not a low friction coefficient road (NO), it is subsequently determined whether or not the wheel is in a skid state (step). ST2-5). As a result, if the wheel is skid (YES), it is determined that the road is a low friction coefficient road (step ST2-6). If the wheel is not skid (NO), the wheel is continuously locked or not. Is determined (step ST2-7). As a result, if the wheel is in a locked state (YES), it is determined that the road is a low friction coefficient road (step ST2-6). If the wheel is not in a locked state (NO), it is determined as a normal road surface (step ST2-). 8).

  FIG. 7 is a timing chart showing temporal changes of respective values when the idling stop control during traveling is performed. In the timing charts of FIGS. 8 and 9, which will be described later, the brake switch on / off, the accelerator opening, the vehicle speed, the ratio of the continuously variable transmission (CVT) 6, the operating state of the engine 3, the engine 3 and the torque converter 4 (turbine) ), The lockup clutch (LC) pressure, the FWD clutch pressure, the driven pulley pressure, and the drive pulley pressure. As shown in the figure, when performing the idling stop control during traveling, the operating state of the engine 3 is the deceleration fuel cut (FC) until the time t1-1 when the lock-up clutch 4c is on. State. When the lock-up clutch 4c is turned off at time t1-1, the engine 3 is in an idle state. After that, when the traveling idle stop permission condition is satisfied at time t1-2 at the vehicle speed V = 10 km / h, the operation state of the engine 3 becomes the idle stop state (the traveling idle stop state). Thereafter, when the traveling idle stop cancellation condition is satisfied at time t-3, the engine 3 is restarted.

  FIG. 8 is a timing chart showing the time change of each value when another mode of running idle stop is executed. As shown in the figure, in another mode of idling stop during normal traveling, the operating state of the engine 3 directly transitions from the deceleration fuel cut state to the idling stop state without passing through the idling state. That is, the vehicle is in the deceleration fuel cut state until time t2-1 when the lock-up clutch 4c is on. When the lock-up clutch 4c is turned off at time t2-1 and at the same time the idle stop permission condition during traveling at the vehicle speed of 10 km / h is satisfied, the idle stop state (idle stop state during traveling) is established. Thereafter, when the traveling idle stop cancel condition is satisfied at time t2-2, the engine 3 is restarted.

  FIG. 9 is a timing chart showing temporal changes of values when the idling stop control during traveling is not performed. As shown in the figure, when the idling stop control during traveling is not performed, the operating state of the engine 3 is a deceleration fuel cut state until time t3-1 when the lockup clutch 4c is in an on state. . When the lock-up clutch 4c is turned off at time t3-1, the operating state of the engine 3 becomes an idle state. Thereafter, when the vehicle stops at time t3-2 (vehicle speed V = 0 km / h), the operating state of the engine 3 becomes the idle stop state. Thereafter, the engine 3 restarts when the vehicle resumes traveling at time t3-3.

  As described above, the automatic stop / start control device for the engine 3 according to the present embodiment is in a state of permitting an idle stop of the engine 3 while the vehicle is traveling as a control mode related to the idle stop (automatic stop) of the engine 3. Idle stop permission mode (automatic stop permission mode during travel) and automatic stop of engine 3 during the travel of the vehicle and disabling the automatic stop of the engine 3 only when the vehicle stops. ) Mode (automatic stop non-permission mode during running). Then, while it is determined that the road surface on which the vehicle is traveling is a low friction coefficient road or a rough road, the control mode related to the automatic stop of the engine 3 is changed from the running idle stop permission mode to the running idle stop mode. When the mode is changed to the stop disapproval mode and it is determined that the road surface condition has returned from the low friction coefficient road or the bad road to the normal road surface, the control mode relating to the automatic stop of the engine 3 is not allowed during the travel. Control to return from the permission mode to the idle stop permission mode during running was performed.

  That is, while it is determined that the road surface on which the vehicle is traveling is a low friction coefficient road or a bad road, the engine 3 is not automatically stopped during traveling in the control mode related to the automatic stop of the engine 3. The mode is changed to the idling stop non-permission mode during traveling that is permitted. As a result, the automatic stop of the running engine 3 is disallowed only when it is determined that the vehicle is actually traveling on a low friction coefficient road such as a frozen road surface or a rough road with many irregularities (during traveling) Therefore, it is possible to ensure good driving performance of the vehicle (to ensure driving merchandise) and to effectively prevent deterioration of fuel consumption of the vehicle.

  Further, when it is determined that the road surface condition has returned from the low friction coefficient road or the rough road to the normal road surface, the control mode relating to the automatic stop of the engine 3 is changed from the automatic stop prohibition mode during travel to the automatic stop during travel. Control to return to the permission mode is performed. That is, even when the control mode related to the automatic stop of the engine 3 is changed to the automatic stop disapproval mode, the switching to the automatic stop permit mode can be performed again by performing the return determination from the low friction coefficient road or the bad road. It becomes possible. Thereby, the further improvement of the fuel consumption of a vehicle can be aimed at, ensuring the favorable running performance of a vehicle.

  Further, since the traveling of the low friction coefficient road is detected according to the duration of the skid traveling state based on the detection value of the wheel speed sensor 73, it is appropriately determined that the road surface on which the vehicle is traveling is the low friction coefficient road. Can be done. Further, since the rough road is detected based on the vehicle speed, the accelerator opening, and the rate of change thereof, it is possible to appropriately determine that the road surface on which the vehicle is traveling is a bad road. And even when a low friction coefficient road or a bad road is detected and the running idle stop disapproval mode is set, the vehicle stop condition is assumed to be essential, and the traveling idle stop disapproval mode is returned to the traveling idle stop permission mode. be able to. Thereby, the fuel consumption deterioration of a vehicle can be prevented effectively. Further, since the idling stop non-permission mode during traveling can be continued until the vehicle is stopped, it is possible to ensure good traveling performance of the vehicle.

  Further, the present embodiment includes a continuously variable transmission 6 for shifting and outputting the rotation of the engine 3 and an output shaft 25 for outputting the rotation shifted by the transmission 6 to the drive wheel DW side, The judgment of the road surface condition by the judging means is a detection value (specifically, a vehicle speed detected by the vehicle speed sensor 73 or a wheel speed sensor 75 detected by a value detected by rotation output from the output shaft 25 to the drive wheel DW side). Wheel speed).

  According to this configuration, it is possible to detect the road surface condition with higher accuracy by detecting the road surface condition during traveling of the vehicle based on the behavior based on the output from the output shaft 25 of the continuously variable transmission 6. In the present embodiment, the continuously variable transmission 6 is a belt-type continuously variable transmission. Based on the road surface condition during traveling detected by the behavior of the output 6 from the output shaft 25 of the transmission 6. By switching between permission and non-permission of idle stop while the vehicle is running, it is possible to effectively prevent the slippage of the belt of the continuously variable transmission 6, and to effectively prevent each part of the transmission 6. Protection is possible.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims and the technical idea described in the specification and drawings. Can be modified. For example, in the above-described embodiment, the determination of the road surface condition where the vehicle is traveling is based on detection values of various sensors mounted on the vehicle such as the accelerator opening sensor 72, the vehicle speed sensor 73, the wheel speed sensor 75, and the acceleration / deceleration sensor 76. Based on the judgment. However, in the automatic stop / start control apparatus for an internal combustion engine according to the present invention, the data for determining the road surface condition where the vehicle is traveling include data detected by various sensor devices mounted on the vehicle as described above. For example, when the vehicle is equipped with a communication terminal capable of communicating with the outside, information including the traveling environment received by the communication terminal (for example, VICS (registered trademark)) Vehicle, vehicle-to-vehicle communication information that is information by communication with other vehicles, road-to-vehicle communication information that is information by communication with devices or sensors installed on the road, etc.) You may comprise so that the condition of a road surface may be judged.

3 Engine 3a Crankshaft 4 Torque converter 4a Pump impeller 4b Turbine runner 4c Lock-up clutch 5 Forward / reverse switching mechanism 6 Continuously variable transmission 11 Planetary gear unit 12 Forward clutch 13 Reverse brake 14 Input shaft 21 Main shaft 22 Input pulley 22a Movable portion 22b Fixed portion 23 Output pulley 23a Movable portion 23b Fixed portion 23d Return spring 24 Transmission belt 25 Sub shaft 25a Gear 71 Engine speed sensor 72 Accelerator opening sensor 73 Vehicle speed sensor 74 Brake sensor 75 Wheel speed sensor DF Differential gear mechanism DW Drive wheel G gear IG1 idler gear IS idler shaft

Claims (7)

This is applied to a vehicle that transmits the rotational force of the output shaft of the internal combustion engine to the drive wheels, and when the predetermined internal combustion engine stop condition is satisfied, the internal combustion engine is automatically stopped, and when the predetermined restart condition is satisfied. In the internal combustion engine automatic stop / start control apparatus for performing the restart process of the internal combustion engine,
Control means for controlling the automatic stop processing and restart processing of the internal combustion engine;
Road surface condition judging means for judging the condition of the road surface on which the vehicle is traveling,
As a control mode related to the automatic stop of the internal combustion engine by the control means, an automatic stop permission mode during travel for permitting automatic stop of the internal combustion engine during travel of the vehicle, and an automatic stop of the internal combustion engine during travel of the vehicle. An automatic stop non-permission mode during travel that permits the automatic stop of the internal combustion engine only when the vehicle is stopped, and
During running of the vehicle, when said status of road surface at the discretion of the road conditions by road state determining means is a determination to the effect that a low friction coefficient road or rough road, the control mode to an automatic stop of the internal combustion engine Change from the automatic stop permission mode during travel to the automatic stop disapproval mode during travel, and then continue the automatic stop disapproval mode during travel until the vehicle stops once,
When it is determined that the road surface condition has returned to the normal road surface from the low friction coefficient road or the bad road after the vehicle has stopped once, the control mode relating to the automatic stop of the internal combustion engine is being executed. An automatic stop / start control device for an internal combustion engine, wherein control for returning from the automatic stop non-permission mode to the automatic stop permission mode during travel is performed. A wheel speed sensor for detecting the rotational speed of each wheel of the vehicle;
The road surface condition judging means is
Based on a detection value of the wheel speed sensor, a skid traveling state in which the driving wheel is idling when the vehicle is accelerated or a locked traveling state in which the driving wheel is in a rotation stopped state when the vehicle is decelerated,
When it is detected that the skid running state or the locked running state has continued for a first time, it is determined that the road surface condition is the low friction coefficient road,
When the skid driving state or the locked driving state is not detected for the second time, and when it is detected that the vehicle has stopped once, the road surface condition has returned from the low friction coefficient road to the normal road surface. 2. The automatic stop / start control apparatus for an internal combustion engine according to claim 1, wherein the determination is made. 3. The automatic stop / start control apparatus for an internal combustion engine according to claim 2, wherein the second time is set to be longer than the first time. Vehicle speed detection means for detecting the vehicle speed;
An accelerator opening detecting means for detecting the accelerator opening,
The road surface condition judging means is
The vehicle speed detected by the vehicle speed detecting means is within a predetermined speed range, the accelerator opening detected by the accelerator opening detecting means is within a predetermined opening range, and the accelerator opening detected by the accelerator opening detecting means is detected. within time rate of change of the predetermined change rate, and acceleration of the vehicle based on the vehicle speed detected by the vehicle speed detecting means changes exceeding a predetermined threshold value becomes a third predetermined number of times or more during the time When it is detected that the road surface is the rough road,
When the acceleration / deceleration of the vehicle does not change the predetermined threshold value exceeding the predetermined number of times during the fourth time, and when it is detected that the vehicle has stopped once, the road surface condition is the bad road. 2. The automatic stop / start control apparatus for an internal combustion engine according to claim 1, wherein it is determined that the vehicle has returned to the normal road surface. 5. The automatic stop / start control apparatus for an internal combustion engine according to claim 4, wherein the fourth time is set to be longer than the third time. A continuously variable transmission mechanism for shifting and outputting the rotation of the internal combustion engine;
An output shaft that outputs the rotation shifted by the speed change mechanism to the drive wheel side,
6. The determination of the road surface state by the road surface state determination means is performed based on a detection value obtained by detecting a value by rotation output from the output shaft to the drive wheel side. The automatic stop / start control device for an internal combustion engine according to claim 1. The automatic stop / start control apparatus for an internal combustion engine according to claim 6, wherein the continuously variable transmission mechanism is a belt-type continuously variable transmission mechanism.

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