JP6023692B2 - Rotation control device for internal combustion engine - Google Patents

Description

  The present invention relates to a rotation control device for an internal combustion engine including control means for controlling the rotation of an internal combustion engine that is a drive source of a vehicle.

  There is a vehicle including an engine (internal combustion engine) that is a driving source, a hydraulic pump (oil pump) that operates with a driving force of the engine, and an automatic transmission that is controlled by hydraulic pressure generated by the hydraulic pump. Such a vehicle automatic transmission includes, as an example, a hydraulic control device controlled by hydraulic pressure generated by a hydraulic pump, and a continuously variable transmission mechanism (CVT) to which hydraulic pressure is supplied by the hydraulic control device, A torque converter is provided between the engine and the speed change mechanism. In recent years, in such a vehicle, in order to improve driving efficiency, a small hydraulic pump having a discharge amount (discharge capacity) as small as possible is mounted as a hydraulic pump that operates with the driving force of the engine. The design is done. In addition, in order to improve the fuel consumption (fuel consumption rate) of the vehicle, a setting is made to keep the idle speed after the engine warm-up operation as low as possible.

  However, in a region where the engine idling speed is low, the amount of hydraulic oil discharged by the hydraulic pump is reduced, and the amount of hydraulic oil discharged is not stable and varies. This influence may cause a delay in the supply of hydraulic oil (CVTF) to the hydraulic control device for controlling the CVT and the torque converter. Due to this, after performing warm-up operation of the engine and automatic transmission, after leaving the operation stopped (so-called soak state) for a predetermined time (for example, about one hour), the vehicle is restarted. When the engine is started, the shift range of the automatic transmission is operated immediately after the engine is restarted, so that the shift range (D range or R range) for vehicle travel is changed from the shift range (P range) when the vehicle is stopped. In the case of switching, there is a slight (for example, several seconds) time lag until the operation associated with the shift range switching is completed and the power transmission by the torque converter is started and the vehicle starts creeping. There was a problem that occurred.

  Patent Document 1 discloses a control for improving fuel consumption by ensuring the sufficient capacity of the hydraulic pump, ensuring the release performance of the lock-up clutch, etc., and making the idle rotation speed as low as possible. When the shift range of the automatic transmission is the traveling range (when the D range is selected), when the oil temperature of the automatic transmission is high, the engine idling speed should be higher than at normal temperature. Is described.

  However, since the control described in Patent Document 1 is a control for increasing the engine idle speed based on the oil temperature of the automatic transmission (hydraulic oil temperature), it is necessary to increase the idle speed of the engine. There is no limit. Therefore, from the viewpoint of improving the fuel efficiency and running performance of the vehicle, it is not always possible to ensure the necessary and sufficient timing as the timing for increasing the engine idle speed. Therefore, there is room for further improvement in terms of improvement in fuel consumption and vehicle running performance.

JP-A-5-280399

  The present invention has been made to solve the above-described problems, and an object of the present invention is to rotate the internal combustion engine that can improve the fuel consumption and running performance of the vehicle by optimizing the rotational speed of the internal combustion engine. It is to provide a control device.

  In order to solve the above problems, an internal combustion engine rotation control device according to the present invention includes an internal combustion engine (10) as a drive source of a vehicle, a hydraulic pressure generator (46a) driven by the internal combustion engine (10), The automatic transmission (1) controlled by the hydraulic pressure generated by the hydraulic pressure generator (46a), and a control means (66) for controlling the rotation of the internal combustion engine (10), the control means (66) The shift range switching determining means (66) for determining that the shift range of the automatic transmission (1) has been switched, and the idle speed of the internal combustion engine (10) based on the determination of the shift range switching determining means (66). Idle speed setting means (66) for setting (N), and automatically within a first time (Dt1) which is a predetermined time from the start of the internal combustion engine (10) by the shift range switching judgment means (66). Transmission (1 Is determined to have been switched to the traveling shift range, the idling engine speed setting means (66) sets the idling engine speed (N) of the internal combustion engine (10) to a first engine speed that is a normal engine speed. An idle speed increase control for increasing from (N1) to a second rotation speed (N2) that is higher than the first rotation speed (N1) is performed.

  In a vehicle equipped with an automatic transmission controlled by a hydraulic pressure generated by a hydraulic pressure generator driven by an internal combustion engine, the operation of the hydraulic pressure generator is performed at a stage where the elapsed time from the startup of the internal combustion engine is short (a stage immediately after the startup). This is a state in which the accumulated discharge amount of hydraulic oil is small. Therefore, when the shift range of the automatic transmission is switched to the shift range for traveling at that stage, the discharge amount and discharge pressure of hydraulic oil necessary for the operation of the automatic transmission accompanying the shift to the shift range for traveling are secured. It may not be possible. On the other hand, according to the rotation control device for an internal combustion engine according to the present invention, when the shift range of the automatic transmission is switched to the travel shift range within a predetermined time from the start of the internal combustion engine, By performing control to increase the idle speed to a higher speed than the normal speed, it is possible to effectively prevent the hydraulic oil discharge amount and the discharge pressure from being insufficient by the hydraulic pressure generator. Accordingly, the required amount and the required pressure of hydraulic oil can be supplied to the automatic transmission controlled by the hydraulic pressure generated by the hydraulic pressure generator at an appropriate timing. As a result, it is possible to ensure an appropriate operation as the operation of the automatic transmission associated with the shift to the traveling shift range.

  In addition, there is a concern that the discharge amount and discharge pressure of hydraulic oil by the hydraulic pressure generator may be insufficient only when the shift range of the automatic transmission is switched to the shift range for traveling within a predetermined time from the start of the internal combustion engine. According to the present invention, the idle speed increase control described above is performed only in such a situation, so that it is not necessary to unnecessarily increase the idle speed of the internal combustion engine. As a result, the idling speed of the internal combustion engine can be kept as low as possible, so that the fuel efficiency of the vehicle can be improved.

  In the above-described rotation control device for an internal combustion engine, the control means (66) is a stop time determination means (66) for determining an elapsed time since the previous stop of the internal combustion engine (10) when the internal combustion engine (10) is started. ) And the elapsed time from the previous stop of the internal combustion engine (10) when the internal combustion engine (10) is started by the stop time determination means (66) exceeds a second time (Dt2) which is a predetermined time. When the internal combustion engine (10) is started by the stop time determination means (66), the elapsed time from the previous stop of the internal combustion engine (10) is the second time ( If it is determined that Dt0) is not exceeded, the idle speed increase control may not be performed.

  In a vehicle equipped with an automatic transmission controlled by hydraulic pressure generated by a hydraulic pressure generator driven by an internal combustion engine, the vehicle is automatically operated from the hydraulic pressure generator according to the elapsed time (so-called soak time) since the previous stop of the internal combustion engine. Since the amount of hydraulic oil existing in the oil passage connected to each part of the transmission gradually decreases, the required discharge amount of hydraulic oil by the hydraulic pressure generator changes according to the soak time. On the other hand, in the above configuration according to the present invention, there is a risk that the amount of hydraulic oil discharged by the hydraulic pressure generator is insufficient by performing the idle speed increase control only when the soak time exceeds a predetermined time. The idling speed of the internal combustion engine can be increased only when there is. As a result, the idle speed of the internal combustion engine does not need to be increased unnecessarily, so that the fuel efficiency of the vehicle can be further improved.

  Further, the above-described rotation control device for the internal combustion engine includes vehicle speed detection means (76) for detecting the vehicle speed (V) of the vehicle, and when the idle rotation speed increase control is performed, the idle rotation speed of the internal combustion engine (10) is set. The vehicle speed (V) detected by the vehicle speed detection means (76) when a third time (Dt3), which is a predetermined time, has elapsed since the first rotation speed (N1) was switched to the second rotation speed (N2). ) Reaches the predetermined vehicle speed (V1), and the idling engine speed increasing control is terminated. After the idling engine speed increasing control is completed, the idling engine speed (N) of the internal combustion engine (10) is set to the second engine speed (N). N2) may be gradually decreased from the first rotation speed (N1).

  According to this configuration, when the predetermined time has elapsed since the execution of the idle speed increase control or when the vehicle speed reaches the predetermined vehicle speed, the idle speed increase control is terminated. It can be minimized. Thereby, the further improvement of the fuel consumption of a vehicle can be aimed at. In addition, after the idle speed increase control is completed, the idle speed of the internal combustion engine is gradually decreased to the normal speed, so that the idle speed of the internal combustion engine rapidly increases after the idle speed increase control is completed. Therefore, it is possible to prevent the driver or passenger of the vehicle from feeling uncomfortable with the change in the idle speed.

  In the internal combustion engine rotation control apparatus, the automatic transmission is provided between the internal combustion engine and the speed change mechanism, a speed change mechanism for shifting and outputting the rotation by the driving force of the internal combustion engine, and hydraulic pressure. And a torque converter controlled by hydraulic pressure generated by the generator.

When the automatic transmission is equipped with a torque converter, the hydraulic oil supply to the torque converter can be supplied at an early stage by ensuring the discharge amount and discharge pressure of the hydraulic oil necessary for the hydraulic pressure generator by the above-described idle speed increase control. Can be completed. Therefore, since transmission of the driving force by the torque converter can be started at an appropriate time, it is possible to prevent a delay from occurring at the timing at which the vehicle starts creeping.
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.

  With the rotation control device for an internal combustion engine according to the present invention, it is possible to improve the fuel consumption and running performance of the vehicle by optimizing the rotation speed of the internal combustion engine.

1 is a schematic diagram illustrating an example of an overall configuration of a vehicle including an engine rotation control device according to an embodiment of the present invention. It is a hydraulic circuit diagram of a hydraulic pressure supply mechanism. It is a timing chart which shows an example of the time change of each value in rotation control of an engine. It is a timing chart which shows another example of the time change of each value in rotation control of an engine. It is a flowchart which shows the procedure of engine rotation control.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating an example of the overall configuration of a vehicle including an engine rotation control device according to an embodiment of the present invention. The vehicle shown in FIG. 1 includes an engine (internal combustion engine) 10 as a drive source, and an automatic transmission 1 that shifts and outputs rotation by the driving force of the engine 10. The automatic transmission 1 includes a transmission mechanism (continuously variable transmission mechanism) 26 including a continuously variable transmission (hereinafter referred to as “CVT”) capable of setting a transmission ratio steplessly, an engine 10, a transmission mechanism 26, and the like. A torque converter 24 and a forward / reverse switching device 28 provided therebetween. The forward / reverse switching device 28 includes a forward clutch 28 a provided to connect / disconnect transmission of the engine 10 driving force to the CVT 26. The vehicle also includes an engine controller 66 and a shift controller 90 that are control devices for controlling the engine 10, the CVT 26, and the forward / reverse switching device 28.

  A throttle valve (not shown) disposed in the intake system of the engine 10 is DBB (Drive) formed of an actuator such as an electric motor, which is disconnected mechanically from an accelerator pedal disposed on the floor of a driver's seat of the vehicle. By Wire) mechanism 16 and opened and closed by DBW mechanism 16.

  The intake air metered by the throttle valve flows through an intake manifold (not shown) and mixes with fuel injected from the injector 20 in the vicinity of the intake port of each cylinder to form an air-fuel mixture. When the valve (not shown) is opened, it flows into the combustion chamber (not shown) of the cylinder. In the combustion chamber, the air-fuel mixture is ignited and combusted, and after driving the piston and rotating the crankshaft 22, the air-fuel mixture is discharged to the outside of the engine 10 as exhaust gas.

  A crankshaft 22 of the engine 10 is connected to a pump / impeller 24a of a torque converter 24, while a turbine runner 24b disposed opposite thereto and receiving fluid (hydraulic oil) is connected to a main shaft (input shaft) MS. The Thereby, the rotation of the crankshaft 22 is input to the CVT 26 via the torque converter 24.

  The CVT 26 is a main shaft MS, more precisely, a drive pulley 26a disposed on the outer peripheral side shaft, and a counter shaft (output shaft) CS parallel to the main shaft MS, more precisely, a driven disposed on the outer peripheral side shaft. The pulley 26b and an endless flexible member, for example, a metal belt 26c, hung around the pulley 26b.

  The drive pulley 26a is fixed to the stationary pulley half 26a1 which is disposed so as not to be rotatable relative to the outer peripheral shaft of the main shaft MS and is not movable in the axial direction, and to the fixed pulley half 26a1 which is not rotatable relative to the outer peripheral shaft of the main shaft MS. The movable pulley half 26a2 is relatively movable in the axial direction. The driven pulley 26b includes a fixed pulley half 26b1 that is not rotatable relative to the outer peripheral shaft of the counter shaft CS and is not movable in the axial direction, and an axial direction relative to the fixed pulley half 26b1 that is not rotatable relative to the counter shaft CS. The movable pulley half 26b2 is relatively movable.

  The CVT 26 is connected to the engine 10 via the forward / reverse switching device 28. The forward / reverse switching device 28 includes a forward clutch (connecting / disconnecting device) 28a that enables the vehicle to travel in the forward direction, a reverse brake clutch 28b that allows the vehicle to travel in the reverse direction, and a planetary gear mechanism disposed therebetween. 28c. CVT 26 is connected to engine 10 via forward clutch 28a.

  In the planetary gear mechanism 28c, the sun gear 28c1 is fixed to the main shaft MS, and the ring gear 28c2 is fixed to the fixed pulley half 26a1 of the drive pulley 26a via the forward clutch 28a. A pinion 28c3 is disposed between the sun gear 28c1 and the ring gear 28c2. Pinion 28c3 is connected to sun gear 28c1 by carrier 28c4. When the reverse brake clutch 28b is operated, the carrier 28c4 is fixed (locked) thereby.

  The rotation of the countershaft CS is transmitted from the secondary shaft (intermediate shaft) SS to the drive wheels 12 via a gear. That is, the rotation of the countershaft CS is transmitted to the secondary shaft SS via the gears 30a and 30b, and the rotation is transmitted from the differential 32 to the left and right drive wheels (only the right side is shown) 12 via the gear 30c.

  In the forward / reverse switching device 28, the forward clutch 28a and the reverse brake clutch 28b are switched by a driver operating a range selector 44 provided in the vehicle driver's seat, for example, in a shift range such as P, R, N, and D. This is done by selecting one. The range selection by the driver's operation of the range selector 44 is transmitted to a manual valve of a hydraulic pressure supply mechanism 46 (described later).

  When, for example, the D, S, L range is selected via the range selector 44, the spool of the manual valve moves accordingly, and hydraulic oil (hydraulic pressure) is discharged from the piston chamber of the reverse brake clutch 28b. The hydraulic pressure is supplied to the piston chamber of the forward clutch 28a, and the forward clutch 28a is fastened.

  When the forward clutch 28a is engaged, all the gears rotate together with the main shaft MS, and the drive pulley 26a is driven in the same direction (forward direction) as the main shaft MS, so that the vehicle travels in the forward direction.

  When the R range is selected, hydraulic oil is discharged from the piston chamber of the forward clutch 28a, while hydraulic pressure is supplied to the piston chamber of the reverse brake clutch 28b, and the reverse brake clutch 28b is operated. Accordingly, the carrier 28c4 is fixed, the ring gear 28c2 is driven in the opposite direction to the sun gear 28c1, the drive pulley 26a is driven in the opposite direction (reverse direction) to the main shaft MS, and the vehicle travels in the reverse direction.

  When the P or N range is selected, the hydraulic oil is discharged from both piston chambers, both the forward clutch 28a and the reverse brake clutch 28b are released, the power transmission via the forward / reverse switching device 28 is cut off, and the engine The power transmission between the motor 10 and the drive pulley 26a of the CVT 26 is cut off.

  FIG. 2 is a hydraulic circuit diagram of the hydraulic pressure supply mechanism 46. As shown in the figure, the hydraulic pressure supply mechanism 46 is provided with a hydraulic pump (hydraulic pressure generator) 46a. The hydraulic pump 46a is a gear pump driven by the engine 10, and pumps up the hydraulic oil stored in the reservoir 46b and pumps it to the PH control valve 46c. The output of the PH control valve 46c (PH pressure (line pressure)) is, on the one hand, the piston chamber of the movable pulley half 26a2 of the drive pulley 26a of the CVT 26 from the oil passage 46d via the first and second regulator valves 46e and 46f. (DR) 26a21 and a driven pulley 26b are connected to a piston chamber (DN) 26b21 of a movable pulley half 26b2 and, on the other hand, are connected to a CR valve 46h via an oil passage 46g.

  The CR valve 46h reduces the PH pressure to generate a CR pressure (control pressure), and supplies the CR pressure (control pressure) to the first, second, and third (electromagnetic) linear solenoid valves 46j, 46k, and 46l from the oil passage 46i. The first and second linear solenoid valves 46j and 46k cause the output pressure determined according to the excitation of the solenoid to act on the first and second regulator valves 46e and 46f, and thus the PH sent from the oil passage 46d. Pressure hydraulic fluid is supplied to the piston chambers 26a21 and 26b21 of the movable pulley halves 26a2 and 26b2, and a pulley side pressure is generated accordingly.

  Accordingly, a pulley side pressure that moves the movable pulley halves 26a2 and 26b2 in the axial direction is generated, the pulley widths of the drive pulley 26a and the driven pulley 26b change, and the winding radius of the belt 26c changes. Thus, by adjusting the pulley side pressure, the ratio (transmission ratio) for transmitting the output of the engine 10 to the drive wheels 12 can be changed steplessly.

  The output (CR pressure) of the CR valve 46h is also connected to the CR shift valve 46n through an oil passage 46m, and from there through a manual valve 46o, the piston chamber (FWD) 28a1 of the forward clutch 28a of the forward / reverse switching device 28. Are connected to the piston chamber (RVS) 28b1 of the reverse brake clutch 28b.

  As described above, the manual valve 46o sends the output of the CR shift valve 46n to the piston chambers 28a1, 28b1 of the forward clutch 28a and the reverse brake clutch 28b according to the position of the range selector 44 operated (selected) by the driver. Connect to one.

  The output of the PH control valve 46c is sent to the TC regulator valve 46q via the oil passage 46p, and the output of the TC regulator valve 46q is connected to the LC shift valve 46s via the LC control valve 46r.

  The output of the LC shift valve 46s is connected to the piston chamber 24c1 of the lockup clutch 24c of the torque converter 24 on the one hand and to the chamber 24c2 on the back side on the other hand.

  When hydraulic oil is supplied to the piston chamber 24c1 via the LC shift valve 46s, the lock-up clutch 24c is engaged (turned on) when supplied from the back chamber 24c2, and is supplied to the back chamber 24c2. On the other hand, when discharged from the piston chamber 24c1, it is released (off). The slip amount of the lockup clutch 24c is determined by the amount of hydraulic oil supplied to the piston chamber 24c1 and the rear chamber 24c2.

  The output of the CR valve 46h is connected to the LC control valve 46r and the LC shift valve 46s through an oil passage 46t, and a fourth linear solenoid valve 46u is inserted in the oil passage 46t. The slip amount of the lock-up clutch 24c is adjusted (controlled) by exciting / de-energizing the solenoid of the fourth linear solenoid valve 46u.

  Returning to the description of FIG. 1, an engine speed sensor 50 is provided at an appropriate position such as near the cam shaft (not shown) of the engine 10. The engine speed sensor (crank angle sensor) 50 outputs a signal indicating the engine speed NE for each predetermined crank angle position of the piston. Further, an absolute pressure sensor 52 is provided at an appropriate position downstream of the throttle valve in the intake system. The absolute pressure sensor 52 outputs a signal proportional to the intake pipe absolute pressure (engine load) PBA.

  A throttle opening sensor 54 is provided in the actuator of the DBW mechanism 16. The throttle opening sensor 54 outputs a signal proportional to the throttle valve opening TH through the rotation amount of the actuator. An accelerator opening sensor 56a is provided in the vicinity of the accelerator pedal 56. The accelerator opening sensor 56a outputs a signal proportional to the accelerator opening AP corresponding to the driver's accelerator pedal operation amount.

  A water temperature sensor 60 is provided in the vicinity of a cooling water passage (not shown) of the engine 10. The water temperature sensor 60 generates an output corresponding to the engine cooling water temperature TW, in other words, the temperature of the engine 10.

  The output of the engine speed sensor 50 or the like is sent to an engine controller (control means) 66. The engine controller 66 includes a microcomputer, determines the target throttle opening based on the sensor outputs, controls the operation of the DBW mechanism 16, and determines the fuel injection amount to drive the injector 20. The engine controller 66 controls the engine speed (idle speed). Therefore, as will be described later, the engine controller 66 determines whether or not the shift range of the automatic transmission 1 is switched to the travel shift range within a predetermined time (DT) from the start of the engine 10. Judgment means, idle speed setting means for increasing the idle speed N of the engine 10 from the normal speed (first speed) N1 to a higher speed (second speed) N2 that is higher than the normal speed (first speed) N1. In addition, the engine 10 has a function as a stop time determination means for determining whether or not a predetermined time has elapsed since the previous stop of the engine 10 when the engine 10 was started.

  An NT sensor (rotational speed sensor) 70 is provided on the main shaft MS. The NT sensor 70 is a pulse indicating the rotational speed of the turbine runner 24b, specifically the rotational speed NT (transmission input shaft rotational speed) of the main shaft MS, more specifically, the input shaft rotational speed of the forward clutch 28a. Output a signal.

  An NDR sensor (rotational speed sensor) 72 is provided in the vicinity of the drive pulley 26 a of the CVT 26. The NDR sensor 72 outputs a pulse signal corresponding to the rotational speed NDR of the drive pulley 26a, in other words, the output shaft rotational speed of the forward clutch 28a.

  An NDN sensor (rotational speed sensor) 74 is provided in the vicinity of the driven pulley 26b. The NDN sensor 74 outputs a pulse signal indicating the rotational speed NDN of the driven pulley 26b, that is, the rotational speed (transmission output shaft rotational speed) of the counter shaft CS. A vehicle speed sensor (rotational speed sensor) 76 is provided in the vicinity of the gear 30b of the secondary shaft SS. The vehicle speed sensor 76 outputs a pulse signal indicating the vehicle speed V through the rotation speed of the secondary shaft SS.

  In the vicinity of the range selector 44, a range selector switch 44a is provided. The range selector switch 44a outputs a signal corresponding to the shift range such as R, N, and D selected by the driver.

  As shown in FIG. 2, a hydraulic pressure sensor 82 is disposed in the oil passage leading to the driven pulley 26 b of the CVT 26 in the hydraulic pressure supply mechanism 46. The hydraulic pressure sensor 82 outputs a signal corresponding to the hydraulic pressure supplied to the piston chamber 26b21 of the movable pulley half 26b2 of the driven pulley 26b. An oil temperature sensor 84 is disposed in the reservoir 46b. The oil temperature sensor 84 outputs a signal corresponding to the oil temperature (temperature TATF of the hydraulic oil ATF). The oil pressure sensor 82 is disposed in an oil passage between the piston chamber 28a1 of the forward clutch 28a and the manual valve 46o or an oil passage leading to the lockup clutch 24c of the torque converter 24, as indicated by an imaginary line in FIG. You may make it detect the hydraulic pressure of the site | part.

  The output of the NT sensor 70 and the like is sent to a shift controller (control means) 90 shown in FIG. The shift controller 90 also includes a microcomputer and is configured to be able to communicate with the engine controller 66. Based on these detected values, the shift controller 90 excites / de-energizes electromagnetic solenoids such as the first and fourth on / off solenoids 46u of the hydraulic pressure supply mechanism 46 to switch the forward / reverse switching device 28, the CVT 26, and the torque converter 24. Control the behavior.

  Here, the specific content of rotation control of the engine 10 by the vehicle of this embodiment is demonstrated in detail. In the rotation control (idle rotation speed control) of the engine 10 by the vehicle of the present embodiment, the shift range of the automatic transmission 1 selected by the range selector 44 is within a first time Dt1 that is a predetermined time from the start of the engine 10. If it is determined that the shift range is changed to a travel shift range (referring to a shift range other than the P range and N range, the same applies hereinafter), the idle speed N of the engine 10 is changed from the normal speed (first speed) N1. Idle rotation speed increase control for increasing the rotation speed to a high rotation speed (second rotation speed) N2 higher than the normal rotation speed N1 is performed. That is, when the shift range is switched to the traveling shift range immediately after the engine 10 is started, control is performed to increase the idle speed N of the engine 10 above the normal speed.

  The idle speed increase control is not performed when it is determined that the second time Dt2 that is a predetermined time has not elapsed since the previous stop of the engine 10 when the engine 10 was started. This is performed only when it is determined that the second time Dt2 has elapsed since the previous stop of the engine 10 at the time of starting.

  Furthermore, when the above-described idle speed increase control is performed, when the third time Dt3, which is a predetermined time, has elapsed since the idle speed of the engine 10 was switched from the normal speed N1 to the high speed N2, or the vehicle speed When the vehicle speed V detected by the sensor 76 reaches a predetermined vehicle speed (threshold value) V1, the idle speed increase control is terminated. Then, after the idle speed increase control is completed, control is performed to gradually decrease the idle speed N of the engine 10 from the high speed N2 to the normal speed N1.

  FIG. 3 is a timing chart showing an example of a time change of each value in the rotation control (idle rotation speed control) of the engine 10. In the timing chart of FIG. 4 and FIG. 4 to be described later, the shift range (shift position) detection signal S by the range selector switch 44a, the engine speed N detected by the engine speed sensor 50, and the vehicle speed detected by the vehicle speed sensor 76. The change of each V is shown. In the timing chart of the figure, the engine 10 is started by turning on the IG (ignition) by the vehicle driver at time t1. In this case, at the time t1 when the engine 10 is started, as the elapsed time (soak time) Dt from the previous stop time t0 of the engine 10, a time equal to or longer than a second time Dt2 that is a predetermined time has elapsed ( Dt ≧ Dt2). Thereafter, at time t2, the shift range is switched to the travel range by the operation of the range selector 44 by the driver. Here, the time Dt from the start of the engine 10 until the shift range is switched is Dt = t2-t1. Then, when the time Dt from the start of the engine 10 until the shift range is switched is within a first time Dt1 that is a predetermined time (Dt ≦ Dt1), the shift range is switched to the travel range. At (time t2), control (idle speed increase control) is performed to increase the rotational speed N of the engine 10 from the normal rotational speed N1 to the high rotational speed N2. The normal rotation speed N1 here is, for example, N1 = 800 rpm, and the high rotation speed N2 is, for example, N2 = 1050 rpm. The first time Dt1 can be set to 3 seconds as an example.

  Thereafter, the idling engine speed N of the engine 10 is maintained at the high engine speed N2, while the driving speed of the engine 10 is transmitted to the drive wheel 12 side so that the vehicle speed V gradually increases. When the vehicle speed V reaches the predetermined vehicle speed (threshold value) V1 at time t3, the idle speed increase control ends at that time. The predetermined vehicle speed V1 here can be set to 3 km / h as an example.

  After the idle speed increase control is completed, control for gradually decreasing (subtracting) the idle speed N of the engine 10 from the high speed N2 to the normal speed N1 is performed. As an example of the mode of reduction of the rotational speed N here, as shown in the figure, the rotational speed N is constant from the high rotational speed N2 to the normal rotational speed N1 so that it becomes a linear function of the elapsed time t from the time t3. Can be reduced by tilt. Further, in this case, as shown by the dotted line in the figure, the subtraction value (slope) of the idle speed N is set in accordance with the value (vehicle speed condition) of the predetermined vehicle speed V1 when the decrease (subtraction) of the idle speed N is started. It may be changed (changed). Thus, at time t4, the idle speed N of the engine 10 becomes the normal speed N1.

  FIG. 4 is a timing chart showing another example of a time change of each value in the rotation control (idle rotation speed control) of the engine 10. In the timing chart shown in FIG. 3, the case where the idle speed increase control is terminated when the vehicle speed V reaches the predetermined vehicle speed V1 is shown. In addition to this, as shown in FIG. The idle rotation speed increase control may be terminated when the elapsed time Dt from the start of the increase control (time t2) reaches a third time Dt3 that is a predetermined time (Dt = Dt3). In this case as well, after the idle speed increase control is completed, control is performed to gradually reduce (subtract) the idle speed N of the engine 10 from the high speed N2 to the normal speed N1.

  FIG. 5 is a flowchart showing a procedure for controlling the rotation of the engine 10. In the flowchart of the same figure, the engine 10 is started by step S1. After that, when the engine 10 is started, it is determined whether or not a second time Dt2 (hereinafter referred to as “predetermined soak time Dt2”), which is a predetermined time since the previous stop of the engine 10, has elapsed. As a method for determining the passage of the predetermined soak time Dt2 here, the difference DTW between the engine cooling water temperature TW1 of the engine 10 at the previous stop detected by the water temperature sensor 60 and the engine cooling water temperature TW2 of the engine 10 at the time of the current start. This can be determined based on (= TW1-TW2). That is, if the engine coolant temperature difference DTW is equal to or less than the predetermined value DTW1, it is determined that the predetermined soak time Dt2 has elapsed. If the engine coolant temperature difference DTW is less than the predetermined value DTW1, the predetermined soak time It is determined that Dt2 has not elapsed. In addition, as a method for determining the elapse of the predetermined soak time Dt2, it is also possible to make a determination based on the actual elapsed time from the previous stop of the engine 10.

  As a result, when the predetermined soak time Dt2 has not elapsed (NO), the idle speed N of the engine 10 is controlled to the normal speed N1 (normal idling) (step S3). On the other hand, if the predetermined soak time Dt2 has elapsed in step S2 (YES), is the shift range switched to the travel shift range within the first time Dt1 that is the predetermined time after the engine 10 is started? It is determined whether or not there has been a shift operation to the traveling shift range (step S4). As a result, after the engine 10 is started, if the shift range is not switched to the travel shift range within the first time Dt1 (NO), the idle speed N of the engine 10 is the normal speed N1 described above. (Normal idling) (step S5). On the other hand, when the shift range is switched to the travel shift range within the first time Dt1 after the engine 10 is started, the idle speed N of the engine 10 is changed from the normal speed N1 to the high speed N2. The idling engine speed increase control (idle up) is increased (step S6).

  As described above, according to the rotation control device for the engine 10 according to the present embodiment, when the shift range of the automatic transmission 1 is switched to the travel shift range within a predetermined time from the start of the engine 10, By performing the control to increase the idle speed of the engine 10, it is possible to prevent the hydraulic oil discharge amount from being lowered by the hydraulic pump 46a. Therefore, since the required amount of hydraulic fluid can be quickly supplied to the automatic transmission 1 controlled by the hydraulic pressure generated by the hydraulic pump 46a, the operation of the automatic transmission 1 can be appropriately performed according to switching to the shift range for traveling. Operation can be ensured.

  That is, as in the present embodiment, in a vehicle equipped with the automatic transmission 1 controlled by the hydraulic pressure generated by the hydraulic pump 46a driven by the engine 10, the elapsed time from the start of the engine 10 is short (immediately after the start). In this stage), the cumulative discharge amount of hydraulic oil due to the operation of the hydraulic pump 46a is small. Therefore, when the shift range of the automatic transmission 1 is switched to the travel shift range at that stage, the discharge amount and discharge of the hydraulic oil necessary for the operation of the automatic transmission 1 associated with the switch to the travel shift range. Pressure may not be secured. On the other hand, according to the rotation control device for the engine 10 of the present embodiment, the shift range of the automatic transmission 1 is switched to the travel shift range within the first time Dt1 that is a predetermined time from the start of the engine 10. In such a case, by performing control to increase the idle speed of the engine 10 to a rotational speed N2 higher than the normal rotational speed N1, it is possible to effectively reduce the amount of hydraulic oil discharged and the discharge pressure from the hydraulic pump 46a. Can be prevented. Accordingly, the required amount and the required pressure of hydraulic oil can be supplied to the automatic transmission 1 controlled by the hydraulic pressure generated by the hydraulic pump 46a at an appropriate timing. Accordingly, it is possible to ensure an appropriate operation as the operation of the automatic transmission 1 associated with the shift to the traveling shift range.

  Further, there is a concern that the discharge amount and discharge pressure of the hydraulic oil by the hydraulic pump 46a are insufficient only when the shift range of the automatic transmission 1 is switched to the shift range for traveling within a predetermined time immediately after the engine 10 is started. However, according to the present invention, the idle speed increase control is performed only in such a situation, so that it is not necessary to increase the idle speed of the engine 10 unnecessarily. Thereby, since the idle speed of the engine 10 can be suppressed as low as possible, the fuel consumption of the vehicle can be improved.

  Further, in the rotation control device for the engine 10 of the present embodiment, when it is determined that the second time Dt2 that is a predetermined time has elapsed since the previous stop of the engine 10 when the engine 10 was started, the idle rotation speed increases. When the engine 10 is started, and it is determined that the second time Dt2 has not elapsed since the previous stop of the engine 10, the idling speed increase control is not performed.

  In a vehicle equipped with the automatic transmission 1 controlled by the hydraulic pressure generated by the hydraulic pump 46a driven by the engine 10, the hydraulic pump 46a is operated according to the elapsed time (so-called soak time) since the last stop of the engine 10. Since the amount of hydraulic oil existing in the oil passage connected to each part of the automatic transmission 1 gradually decreases, the required discharge amount of hydraulic oil by the hydraulic pump 46a changes according to the soak time. On the other hand, in the above configuration according to the present invention, the idle oil speed increase control is performed only when the soak time exceeds the second time Dt2, thereby reducing the amount of hydraulic oil discharged by the hydraulic pump 46a. It is possible to increase the idle speed of the engine 10 only when there is a risk of shortage. As a result, the idle speed of the engine 10 does not need to be increased unnecessarily, so that the fuel efficiency of the vehicle can be further improved.

  Further, in the rotation control device for the engine 10 of the present embodiment, when the idle rotation speed increase control is performed, the idle rotation speed of the engine 10 is switched to the high rotation speed (second rotation speed) N2 for a predetermined time (first time). 3 when the time Dt3) elapses or when the vehicle speed V reaches the predetermined vehicle speed V1, the idle speed increase control is terminated. After the idle speed increase control is terminated, the idle speed of the engine 10 is increased to a high speed. The number is gradually decreased from the number N2 to the normal rotational speed N1.

  According to this configuration, the execution time of the idle speed increase control can be minimized. Thereby, the further improvement of the fuel consumption of a vehicle can be aimed at. In addition, after the idle speed increase control is completed, the idle speed of the engine 10 is gradually decreased to the normal speed, so that the idle speed of the engine 10 rapidly increases after the idle speed increase control is completed. Therefore, it is possible to prevent the driver or passenger of the vehicle from feeling uncomfortable with the change in the idle speed.

  The automatic transmission 1 included in the vehicle of the present embodiment is provided between a transmission mechanism 26 for shifting and outputting rotation by the driving force of the engine 10, and between the engine 10 and the transmission mechanism 26. And a torque converter 24 controlled by the hydraulic pressure generated by the pump 46a. As described above, when the automatic transmission 1 includes the torque converter 24, the amount of hydraulic oil and the discharge pressure necessary for the hydraulic pump 46a are secured by the above-described idle speed increase control, so that the torque converter 24 can be secured. The supply of the hydraulic oil can be completed at an early stage. Therefore, since transmission of the driving force by the torque converter can be started at an appropriate time, it is possible to prevent a delay from occurring at the timing at which the vehicle starts creeping.

  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.

1 automatic transmission 10 engine 12 drive wheel 26 continuously variable transmission mechanism (transmission mechanism)
28 Forward / reverse switching device 44 Range selector 44a Range selector switch 46 Hydraulic supply mechanism 46a Hydraulic pump (hydraulic pressure generator)
DESCRIPTION OF SYMBOLS 50 Engine speed sensor 52 Absolute pressure sensor 54 Throttle opening sensor 56 Accelerator pedal 56a Accelerator opening sensor 60 Water temperature sensor 66 Engine controller (control means)
76 Vehicle speed sensor (vehicle speed detection means)
82 Hydraulic sensor 84 Oil temperature sensor 90 Shift controller Dt1 Predetermined time (first time)
Dt2 Predetermined soak time (second time)
Dt3 Predetermined time (third time)
N1 Normal speed (first speed)
N2 High rotation speed (second rotation speed)
TW Engine cooling water temperature V Vehicle speed V1 Predetermined vehicle speed

Claims (4)

An internal combustion engine as a drive source of the vehicle;
A hydraulic pressure generator driven by the internal combustion engine;
An automatic transmission controlled by hydraulic pressure generated by the hydraulic pressure generator;
Control means for controlling the rotation of the internal combustion engine,
The control means includes
Shift range switching determining means for determining that the shift range of the automatic transmission has been switched;
Idle speed setting means for setting the idle speed of the internal combustion engine based on the determination of the shift range switching determination means,
The idle rotation only when the shift range switching determining means determines that the shift range of the automatic transmission has been switched to the traveling shift range within a first time that is a predetermined time from the start of the internal combustion engine. Idle rotation speed increase control for increasing the idle rotation speed of the internal combustion engine from a first rotation speed that is a normal rotation speed to a second rotation speed that is higher than the first rotation speed by a number setting means. A rotation control device for an internal combustion engine. The control means includes
A stop time determining means for determining an elapsed time from the previous stop of the internal combustion engine at the start of the internal combustion engine;
When the stop time determining means determines that the elapsed time from the previous stop of the internal combustion engine exceeds a second time which is a predetermined time when the internal combustion engine is started, the idle speed increase control is performed. ,
When the stop time determination means determines that the elapsed time from the previous stop of the internal combustion engine does not exceed the second time when the internal combustion engine is started, the idle speed increase control is not performed. The rotation control apparatus for an internal combustion engine according to claim 1, wherein Vehicle speed detecting means for detecting the vehicle speed of the vehicle,
When the idle speed increase control is performed, when a third time, which is a predetermined time, has elapsed since the idle speed of the internal combustion engine was switched from the first speed to the second speed, or When the vehicle speed detected by the vehicle speed detection means reaches a predetermined vehicle speed, the idle speed increase control is terminated,
3. The internal combustion engine according to claim 2, wherein after completion of the idle speed increase control, the idle speed of the internal combustion engine is gradually decreased from the second speed to the first speed. Rotation control device. The automatic transmission is
A speed change mechanism for shifting and outputting the rotation by the driving force of the internal combustion engine;
4. A torque converter provided between the internal combustion engine and the speed change mechanism and controlled by a hydraulic pressure generated by the hydraulic pressure generating device. The internal combustion engine rotation control device.

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