JP6406835B2 - Control device - Google Patents

Description

  The present invention relates to a control device that controls an internal combustion engine mounted on a vehicle.

  In an internal combustion engine mounted on a vehicle, it is known to perform a fuel cut that interrupts fuel injection in accordance with the driving situation (see, for example, Patent Document 1 below). Normally, when the accelerator pedal depression amount is 0 or less than a threshold value close to 0 and the engine speed is equal to or higher than the fuel cut permission speed, the fuel cut is started assuming that the fuel cut condition is satisfied. Then, when any fuel cut end condition is satisfied, such as when the accelerator pedal depression amount exceeds the threshold value, or the engine speed decreases to the fuel cut return speed, the fuel cut ends and the fuel injection resumes. .

  Recently, it has also become common to implement an idle stop that stops the idle rotation of the internal combustion engine while the vehicle is stopped due to a signal waiting or the like (see, for example, Patent Document 2 below). In the known idling stop system, the internal combustion engine is stopped when various conditions such as the vehicle speed is lower than a predetermined value, the brake pedal is depressed, and the coolant temperature and the battery voltage are sufficiently high. After the idling stop, the internal combustion engine is restarted when there is a restart request such as the driver removing his foot from the brake pedal or depressing the accelerator pedal.

Japanese Patent Laid-Open No. 10-030477 JP 2012-137018 A

  When the driver removes his or her foot from the accelerator pedal while the vehicle is running and the vehicle decelerates and stops, first the fuel cut condition is satisfied and the fuel cut is started, and then the engine shifts to idle stop.

  However, fuel injection is not not performed at all from the start of fuel cut to idle stop. Actually, the fuel cut end condition is satisfied when the vehicle speed of the vehicle drops to about 10 km / h, and fuel injection and ignition combustion may be temporarily resumed. Thereafter, the idling stop condition is established at a vehicle speed of about 9 km / h, and the fuel injection is again terminated, whereby the internal combustion engine and the vehicle are further decelerated, leading to idling stop and stopping.

  Such behavior also depends on the disconnection of the lock-up clutch of the torque converter interposed between the crankshaft of the internal combustion engine and the axle (drive wheel). If the lockup clutch is disengaged during inertial fuel cut, the torque transmitted from the axle side to the crankshaft side is lost, and the engine speed drops rapidly and falls below the fuel cut return speed. As a result, the fuel cut end condition is satisfied before the idle stop condition is satisfied.

  Needless to say, the temporary fuel injection that occurs between the fuel cut and the idle stop is a factor that deteriorates the effective fuel consumption.

  The present invention, which has been made paying attention to the above-mentioned problems, is intended to further improve the fuel consumption performance of an idle stop vehicle.

In the present invention, the fuel cut is performed to temporarily stop the fuel injection when the fuel cut condition is satisfied, the fuel cut is ended and the fuel injection is restarted when the fuel cut end condition is satisfied, and the idle stop condition is satisfied. The idle stop is performed to stop the idle rotation of the internal combustion engine, and when the idle stop end condition is satisfied, the idle stop is ended and the internal combustion engine is restarted. Prior to establishment, the lockup of the torque converter interposed between the crankshaft and the axle of the internal combustion engine is released, and the fuel cut end condition is satisfied when the engine speed falls below the fuel cut return speed during fuel cut as the fuel injection resumes, during the fuel cut, the engine speed drops below the fuel cut return rotational speed In the case where the lock-up torque converter is released before, among the plurality of conditions to be idle stop condition, the amount of depression or the master cylinder pressure of the brake pedal becomes equal to or more than the threshold value and that is below the vehicle speed with the current vehicle speed Predetermined conditions other than the above conditions have already been established, and the condition that the brake pedal depression amount or master cylinder pressure is greater than or equal to the threshold value and the current vehicle speed is below a certain vehicle speed has not yet been established, but the brake pedal depression amount Alternatively, in a situation in which the idle stop can be started because the condition that the master cylinder pressure is equal to or higher than the threshold value and the current vehicle speed is equal to or lower than a certain vehicle speed is satisfied, the engine is in a fuel cut state and the predetermined the fuel cut return rotational speed in comparison with the situation where the condition is not satisfied You configure the controller to lower.

  According to the present invention, it is possible to further improve the fuel consumption performance of the idle stop vehicle.

The figure which shows the structure of the internal combustion engine and control apparatus in one Embodiment of this invention. The figure which shows the structure of the drive system of the vehicle in the embodiment. The figure which shows the electric circuit for the control apparatus of the embodiment to operate the compressor of various electric loads or an air conditioner. The timing diagram which shows the content of the control which the control apparatus of the internal combustion engine of the embodiment implements.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of an internal combustion engine for a vehicle in the present embodiment. The internal combustion engine in the present embodiment is a spark ignition type four-stroke engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). In the vicinity of the intake port of each cylinder 1, an injector 11 for injecting fuel is provided. A spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives spark voltage generated by the ignition coil and causes spark discharge between the center electrode and the ground electrode.

  The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream.

  The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. An exhaust manifold 42 and an exhaust purification three-way catalyst 41 are disposed on the exhaust passage 4.

  The brake booster 5 introduces intake negative pressure from a portion of the intake passage 3 downstream of the throttle valve 32 (particularly, the surge tank 33), and boosts the pedal effort of the brake pedal using the negative pressure. It is widely known. The brake booster 5 has a constant pressure chamber for storing negative pressure and a variable pressure chamber for applying atmospheric pressure, and the constant pressure chamber is connected to the intake passage 3 via a negative pressure pipe 51. The negative pressure line 51 guides the intake negative pressure downstream of the throttle valve 32 to the constant pressure chamber. A check valve 52 is provided on the negative pressure line 51 to keep the negative pressure in the constant pressure chamber and prevent the positive pressure from being applied to the constant pressure chamber.

  When the brake pedal is not operated by the driver, the constant pressure chamber and the variable pressure chamber communicate with each other, and the variable pressure chamber is isolated from the atmospheric pressure. When the brake pedal is operated, the constant pressure chamber and the variable pressure chamber are interrupted, and the atmosphere is introduced into the variable pressure chamber. As a result, the pressure difference between the constant pressure chamber and the variable pressure chamber becomes a control pressure that boosts the depression force of the brake pedal. The brake pedal force amplified by the brake booster 5 is converted into hydraulic pressure in the master cylinder 6. The hydraulic fluid pressure output from the master cylinder 6 is transmitted to a brake device (not shown) such as a brake caliper or a wheel cylinder via a hydraulic circuit (not shown), and is used for braking the vehicle by the brake device.

  FIG. 2 shows an example of a drive system provided in the vehicle. This drive system includes a torque converter 7 and automatic transmissions 8 and 9. In the present embodiment, a forward / reverse switching device 8 using a planetary gear mechanism and a belt-type CVT (Continuously Variable Transmission) 9 which is a type of continuously variable transmission are adopted as components of the automatic transmissions 8 and 9. Yes.

  The rotational torque output from the internal combustion engine is input from the crankshaft of the internal combustion engine to the pump impeller 71 on the input side of the torque converter 7 and transmitted to the turbine runner 72 on the output side. The rotation of the turbine runner 72 is transmitted to the drive shaft 94 of the CVT 9 via the forward / reverse switching device 8 and rotates the driven shaft 95 through a shift in the CVT 9. The rotation of the driven shaft 95 is transmitted to the output gear 101. The output gear 101 meshes with the ring gear 102 of the differential device, and rotates the axle 103 and the drive wheels (not shown) via the differential device.

  The torque converter 7 includes a lockup mechanism. The lock-up mechanism is known in this field, and a lock-up clutch 73 that fastens the input side and the output side of the torque converter 7 so as not to rotate relative to each other, and an operation for switching the connection of the lock-up clutch 73. A lock-up solenoid valve (not shown) for controlling the hydraulic pressure (hydraulic pressure) is used as an element. The lockup solenoid valve is a flow rate control valve that receives a control signal l and changes its opening.

  In a vehicle equipped with CVT 9, when the vehicle speed is a predetermined value (for example, 10 km / h) or more, the torque converter 7 is almost always locked up. When the vehicle speed is equal to or lower than the predetermined value, the lockup of the torque converter 7 is released. During lockup, the lockup clutch 73 is pressed against the torque converter cover 74 and rotates together with the torque converter cover 74. The engine torque input to the input side (drive plate) of the torque converter 7 at the time of lock-up is output from the torque converter cover 74 via the lock-up clutch 73 and thus to the forward / reverse switching device 8. Communicated directly to. At the time of lockup, the speed ratio, which is the ratio of the output side rotational speed of the torque converter 7 to the input side rotational speed, is 1.

  In turn, the lock-up clutch 73 is separated from the torque converter cover 74 at the time of non-lock-up. At the time of non-lock-up, the engine torque input to the input side of the torque converter 7 is transmitted from the torque converter cover 74 to the pump impeller 71 and the turbine 72 and is transmitted to the forward / reverse switching device 8. At the time of non-lock-up, the speed ratio of the torque converter 7 becomes smaller or larger than 1 depending on the driving state.

  In the forward / reverse switching device 8, the sun gear 81 communicates with the turbine runner 72, and the ring gear 82 communicates with the drive shaft 94. Between the planetary carrier 83 that supports the planetary gear 831 and the transmission case, a forward brake 84 that is a hydraulic clutch that can be connected and disconnected is interposed. Further, a reverse clutch 85, which is a hydraulic clutch capable of switching connection / disconnection, is also interposed between the planetary carrier 83 and the sun gear 81 (or the output side of the torque converter 7).

  In the D range of the traveling range, the forward brake 84 is engaged and the reverse clutch 85 is disconnected. As a result, the rotation of the output shaft of the torque converter 7 is reversed and decelerated and transmitted to the drive shaft 94 for forward travel. In turn, in the R range, the reverse clutch 85 is engaged and the forward brake 84 is disconnected. As a result, the sun gear 81 and the planetary carrier 83 rotate integrally, and the output shaft of the torque converter 7 and the drive shaft 94 are directly connected to perform reverse travel. A solenoid valve (not shown) that controls the hydraulic pressure for driving the forward brake 84 or the reverse clutch 85 to connect / disconnect is a flow rate control valve that receives a control signal m and changes its opening.

  In the N range and P range, which are non-traveling ranges, both the forward brake 84 and the reverse clutch 85 are disconnected.

  The CVT 9 includes a driving pulley 91 and a driven pulley 92, and a belt 93 wound around the pulleys 91 and 92 as elements. The drive pulley 91 is disposed behind the movable sheave 912, a fixed sheave 911 fixed to the drive shaft 94, a movable sheave 912 supported on the drive shaft 91 via a roller spline so as to be displaceable in the axial direction. A hydraulic servo 913 is provided, and the gear ratio can be changed steplessly by operating the hydraulic servo 913 and displacing the movable sheave 912. The driven pulley 92 is disposed on the back of the movable sheave 922, a fixed sheave 921 fixed to the driven shaft 95, a movable sheave 922 supported on the driven shaft 95 via a roller spline so as to be axially displaceable. A hydraulic servo 923 is provided, and a belt thrust necessary for torque transmission is applied by operating the hydraulic servo 923 and displacing the movable sheave 922.

  The vehicle is accompanied by a plurality of external loads. Specific examples of external loads include air conditioner refrigerant compression compressors, various electrical loads such as air conditioner blowers, defoggers for removing fog on rear glass, audio equipment, car navigation systems, and lighting (heads) Lamps, tail lamps, fog lamps, turn signals (turn signal lamps, etc.), radiator fans for cooling cooling water, electric power steering devices, and the like.

  The compressor of the air conditioner is rotationally driven in response to transmission of rotational torque from the crankshaft of the internal combustion engine, and compresses the refrigerant. As shown in FIG. 3, a magnet clutch 61 that can be connected and disconnected is interposed between the compressor and the crankshaft of the internal combustion engine. When the air conditioner is operated, current from the in-vehicle battery 62 and / or the generator (alternator or motor generator) 63 is supplied to the magnet clutch 61 and the magnet clutch 61 is engaged. On the contrary, when the air conditioner is not operated, the magnet clutch 61 is not energized and the clutch 61 is disconnected. Energization and disconnection of the magnet clutch 61 is performed by turning ON / OFF the relay switch 64.

  The motor 66 that rotationally drives the blower for blower and the heating wire heater 68 laid on the rear glass as a defogger operate by receiving power supply from the battery 62 and / or the generator 63. Energization and interruption of the motor 66 and the heater 68 are performed by turning on / off the relay switch 67 or starting / extinguishing a semiconductor switching element (power device represented by a power transistor, power MOSFET, etc.) 69.

  The same applies to audio devices, car navigation systems, illuminating lights, turn indicators (winkers), motors that rotate the radiator fan, and other electrical loads.

  A generator 63, which is a source of power supply to the electric load, is driven to rotate by receiving a driving force transmitted from the crankshaft of the internal combustion engine to generate electric power. The generator 63 is connected to the crankshaft via a winding transmission mechanism having a belt and a pulley as elements. The magnitude of the voltage generated and output by the generator 63 can be controlled via the regulator 65. The regulator 65 is a known IC type attached to the generator 63, and performs a switching operation for switching ON / OFF the energization of the field coil of the generator 63.

  The output voltage of the generator 63, that is, the voltage induced in the stator coil of the generator 63 increases in proportion to fDUTY, which is the DUTY ratio of the field current flowing through the field coil. The regulator 65 receives a signal r commanding the output voltage of the generator 63, and performs PWM control for adjusting fDUTY so as to realize the commanded output voltage. With this PWM control, the power generated by the generator 63 can be increased or decreased. The amount of power generated by the generator 63, in other words, the amount of charge to the battery 62 and / or the amount of power supplied to the electrical load increases as fDUTY increases and decreases as fDUTY decreases.

  The generator 63 becomes a mechanical load when viewed from the internal combustion engine. When the output voltage of the generator 63 exceeds the voltage of the battery 62, the battery 62 is charged and power is supplied from the generator 63 to the electric load. That is, the generator 63 works to generate electric energy by consuming energy of rotation of the crankshaft. The amount of charge to the battery 62 and the amount of power supplied to the electric load depend on the potential difference between the output voltage of the generator 63 and the battery voltage.

  Conversely, when the output voltage of the generator 63 is less than or close to the battery voltage, the battery 62 is not charged, and no power is supplied from the generator 63 to the electric load (from the battery 62 to the electric load). May be powered). In other words, the generator 63 does not do work that consumes the energy of rotation of the crankshaft, or the work becomes small.

  An ECU (Electronic Control Unit) 0 that is a control device of the present embodiment is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like.

  The input interface includes a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal b output from an engine rotation sensor that detects the rotation angle and engine speed of the crankshaft, and depression of an accelerator pedal. Or an accelerator opening signal c output from a sensor that detects the amount or the opening of the throttle valve 32 as an accelerator opening (engine output required by the driver, that is, a required load), a sensor or master that detects the depression amount of the brake pedal A brake pedaling amount signal d output from a sensor that detects a master cylinder pressure, which is a pressure of hydraulic fluid discharged from the cylinder 6, a temperature that detects an intake air temperature and an intake pressure in the intake passage 3 (particularly, the surge tank 33).・ Detects the intake air temperature / intake pressure signal e output from the pressure sensor and the coolant temperature indicating the temperature of the internal combustion engine Cooling water temperature signal f output from the water temperature sensor, cam angle signal g output from the cam angle sensor at a plurality of cam angles of the intake camshaft or exhaust camshaft, and an indicator (battery indicating the charging state of the in-vehicle battery 62 Battery status signal h output from a sensor for detecting current, battery voltage and / or battery temperature), shift range signal p output from a sensor (shift position switch) for knowing the range of the shift lever, steering It is output from a sensor for detecting steering torque, steering amount (angle) or steering speed (change amount of steering amount per unit time) of the steering wheel input to the wheel (the steering wheel operated by the driver for steering). The steering amount signal q and the magnitude of the negative pressure stored in the brake booster 5 are detected. Brake booster negative pressure signal r or the like to be output from the force sensors are input.

From the output interface, an ignition signal i for the igniter of the spark plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and a lock for connection / disconnection switching of the lockup clutch 73. Opening control signal l for up solenoid valve, opening control signal m for solenoid valve for switching connection / disconnection of forward brake 84 or reverse clutch 85, transmission ratio control signal n for CVT9, magnet clutch 61 The clutch engagement signal s is generated for the switch 64 on the electric circuit to be energized, and the switch ON signals t and u and the alternator 63 are generated for the switches 67 and 69 on the electric circuit for energizing the motor 66, the heater 68 and other electric loads. Output voltage instruction signal v etc. to voltage regulator 65 that controls the voltage That.
Etc. are output.

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 obtains various information a, b, c, d, e, f, g, h, p, q, r necessary for operation control of the internal combustion engine via the input interface, and knows the engine speed. The amount of intake air charged in the cylinder 1 is estimated. Based on the engine speed and intake air amount, etc., the required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, and torque converter 7 lock-up are adjusted. Various operation parameters such as whether or not to perform the transmission, the gear ratio of the CVT 9 and the amount of power generated by the generator 63 (output voltage) are determined. The ECU 0 applies various control signals i, j, k, l, m, n, s, t, u, v corresponding to the operation parameters via the output interface.

  Further, the ECU 0 inputs a control signal o to the electric motor (starter (cell motor) or motor generator) when the internal combustion engine is started (a cold start or a return from an idling stop). Cranking is performed by rotating the crankshaft with an electric motor. Cranking ends when the internal combustion engine starts from the first explosion to a continuous explosion and the engine speed, that is, the rotation speed of the crankshaft, exceeds a judgment value determined according to the coolant temperature, etc. (assuming that the explosion has been completed) To do.

  The ECU 0 of this embodiment executes a fuel cut that interrupts the fuel supply to the cylinder 1 when a predetermined fuel cut condition is satisfied. The ECU 0 determines that the fuel cut condition is satisfied at least when the accelerator opening is 0 or less than a threshold value close to 0 and the engine speed is equal to or higher than the fuel cut permission speed.

  Incidentally, even if the fuel cut condition is satisfied, the fuel injection (and ignition) from the injector 11 is not immediately stopped. If the fuel supply is cut off suddenly when the engine torque is relatively large, a torque shock that causes the engine speed and the vehicle speed to drop stepwise occurs, causing the passengers including the driver to feel the shock. In order to reduce the torque shock, the fuel injection is stopped only after the elapse of the delay time after the fuel cut condition is satisfied. During this delay time, the ignition timing is retarded and the engine torque is actively reduced.

  When the predetermined fuel cut end condition is satisfied after the start of the fuel cut and before the idle stop condition described later is satisfied (that is, before the start of the idle stop), the fuel cut is ended, and the fuel injection (and Ignition) is resumed. The ECU 0 determines that the fuel cut end condition is satisfied, for example, when the accelerator opening degree exceeds the threshold value, or when the engine speed decreases until it falls below the fuel cut return speed.

  In addition, the ECU 0 executes an idle stop that stops the idle rotation of the internal combustion engine when a predetermined idle stop condition is satisfied. The ECU 0 has a brake pedal depression amount or a master cylinder pressure that is equal to or higher than a threshold value, a cooling water temperature of the internal combustion engine is higher than a predetermined level, a terminal voltage of the battery 62 is higher than a predetermined level, and an output voltage of the generator 63 is lower than a predetermined level. The generator 63 is not substantially generating electricity, the magnet clutch 61 is disconnected, the refrigerant compression compressor of the air conditioner is not operating, the shift range is the traveling range, the hood or the door of the driver's seat Is not open, the direction indicator is not lit, the steering torque input to the steering wheel or the steering amount or steering speed of the steering wheel is below a predetermined value, and from the end of the previous idle stop to a certain vehicle speed or higher Has a history of acceleration and the current vehicle speed is below a certain vehicle speed (for example, the vehicle speed is 13.5 km / h or more) With a possible dropped to 13km / h, or dropped to 7km / h from 9.5km / h or higher), such conditions are satisfied across the board, the idle stop condition is judged that satisfied.

  If the idle stop condition is satisfied without satisfying the fuel cut end condition after the start of the fuel cut, the fuel injection state is not resumed and the engine is shifted to the idle stop while the fuel cut state is maintained.

  When a predetermined idle stop end condition is satisfied after the idle stop condition is satisfied, the internal combustion engine is restarted. The ECU 0 determines that the brake pedal depression amount or the master cylinder pressure is 0 or less than a threshold value close to 0 (the brake pedal is no longer depressed), and conversely, the brake pedal depression amount or the master cylinder pressure further increases (brake The idle stop termination condition is met when the pedal is depressed more), the accelerator opening is increased (the accelerator pedal is depressed), or the predetermined time (3 minutes) has elapsed in the idle stop state. Judge that it was done.

  In addition, the ECU 0 according to the present embodiment terminates the fuel cut in a situation where a predetermined condition forming a part of the idle stop condition is satisfied during the fuel cut and the idle stop can be started by the satisfaction of another condition. Reduce the fuel-cut return rotation speed related to the conditions below normal.

  FIG. 4 shows the content of control when the vehicle is decelerated by the ECU 0 of the present embodiment. In FIG. 4, the thick solid line and the thin solid line represent the transition of the engine speed, and the broken line and the chain line represent the fuel cut return speed according to the fuel cut end condition. Further, the fuel cut return rotation speed (1000 rpm) when the predetermined condition is satisfied during the fuel cut is drawn by a chain line, and the fuel cut return rotation speed (1100 rpm) when the predetermined condition is not satisfied is indicated by a broken line. I'm drawing.

  The predetermined condition referred to here is the total of conditions other than the conditions relating to the operation of the brake pedal and the vehicle speed among the idle stop conditions. Specifically, the cooling water temperature of the internal combustion engine is higher than a predetermined level, the terminal voltage of the battery 62 is higher than a predetermined level, the output voltage of the generator 63 is lower than the predetermined level, the magnet clutch 61 is disconnected, the shift range Is the driving range, the hood or the door of the driver's seat is not open, the direction indicator is not lit, and the steering torque input to the steering wheel or the steering amount or steering speed of the steering wheel is below a predetermined level. There is a certain condition in this embodiment.

  In particular, the fact that the output voltage of the generator 63 is below a predetermined value and that the magnet clutch 61 is disengaged (the refrigerant compression compressor is not in operation) is included in the predetermined conditions. Is intended to avoid.

Under the condition where the predetermined condition is satisfied, when the other conditions are satisfied, that is, the brake pedal depression amount or the master cylinder pressure is equal to or higher than the threshold value, and the vehicle speed is decreased from 13.5 km / h to 13 km / h. Alternatively, the idle stop can be started when the speed decreases from 9.5 km / h or more to 7 km / h.

When the fuel cut is started, the vehicle starts coasting, and the rotation of the crankshaft of the internal combustion engine is maintained by the torque transmitted from the axle 103. Then, the lock-up of the torque converter 7 is released at time t ₁ when the vehicle speed is reduced to about 10 km / h, and the deceleration of the engine speed increases after time t ₁ . Thus, if the above predetermined condition is not satisfied, because the engine speed at an early time point t ₂ than the time t ₃ when the idle stop condition is satisfied is less than the normal fuel cut return rotational speed (dashed line), Fuel injection is temporarily resumed. Thereafter, the idle stop condition idle stop from the established time t ₃ is started and stopped again fuel injection. The transition of the engine speed in this case is drawn with a thin solid line.

In contrast, if the above predetermined condition is satisfied, a fuel cut return rotational speed because it is pulled down than normal, the engine speed at time t ₃ before the idle stop condition is satisfied cut fuel It will not fall below the return speed (dashed line). Therefore, the stop of fuel injection is consistently maintained after the start of fuel cut until the start of idle stop. In addition, the transition of the engine speed in this case is drawn with a thick solid line.

  In the present embodiment, a fuel cut that temporarily stops fuel injection is performed when the fuel cut condition is satisfied, the fuel cut is ended and fuel injection is restarted when the fuel cut end condition is satisfied, and the idle stop condition In accordance with the establishment of the engine, an idle stop for stopping the idle rotation of the internal combustion engine is performed, and when the idle stop end condition is satisfied, the idle stop is ended and the internal combustion engine is restarted. , Including that the engine speed is lower than the fuel cut return speed, a predetermined condition that constitutes a part of the idle stop condition is satisfied during the fuel cut, and the idle stop is started when the other conditions are satisfied In the situation where the engine can be operated, the control device 0 for the internal combustion engine which reduces the fuel cut return rotational speed as compared with the case where it is not. Form was.

  According to the present embodiment, when the vehicle does not depress the accelerator pedal, the idle stop condition is satisfied earlier than the fuel cut end condition is satisfied, and consistently from the fuel cut to the idle stop. This eliminates the need for fuel injection. Since the temporary fuel injection between the fuel cut and the idle stop can be eliminated, the fuel consumption of the idle stop vehicle can be further reduced.

  The present invention is not limited to the embodiment described in detail above. For example, the predetermined condition for reducing the fuel cut return rotational speed from a normal value is not limited to that in the above embodiment. Except for the generator 63 and the compressor for compressing the refrigerant, the load of the auxiliary machine (cooling water pump, lubricating oil pump, etc.) that operates by receiving rotational torque from the crankshaft of the internal combustion engine may be included in the predetermined condition. Good. In that case, the fuel cut return rotational speed is allowed to be lowered at least on the condition that the load on the internal combustion engine of the auxiliary machine is not more than a predetermined value.

  In addition, the specific configuration of each unit, the processing procedure, and the like can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to control of an internal combustion engine mounted on a vehicle.

0 ... Control unit (ECU)
DESCRIPTION OF SYMBOLS 1 ... Cylinder 11 ... Injector 12 ... Spark plug

Claims (1)

When the fuel cut condition is satisfied, the fuel cut is temporarily stopped. When the fuel cut end condition is satisfied, the fuel cut is ended and the fuel injection is restarted. When the idle stop condition is satisfied, the internal combustion engine. The idle stop is performed to stop the idle rotation of the engine, and when the idle stop end condition is satisfied, the idle stop is ended and the internal combustion engine is restarted.
After the fuel cut condition is established and before the idle stop condition is established, the lock-up of the torque converter interposed between the crankshaft and the axle of the internal combustion engine is released,
When the engine speed falls below the fuel cut return speed during the fuel cut, the fuel injection is restarted assuming that the fuel cut end condition is satisfied,
During a fuel cut , if the torque converter lockup is released before the engine speed falls below the fuel cut return speed , the brake pedal depression amount or master cylinder among the multiple conditions that become the idle stop conditions Predetermined conditions other than the condition that the pressure is greater than or equal to the threshold and the current vehicle speed is less than or equal to a certain vehicle speed have already been established, and the brake pedal depression amount or master cylinder pressure is still greater than the threshold and the current vehicle speed is less than or equal to the certain vehicle speed Although condition is not satisfied that is, starting the idle stop as idle stop condition by the occurrence of conditions that the amount of depression or the master cylinder pressure of the brake pedal is lower vehicle speed that is and the current vehicle speed than the threshold is satisfied in situations that may be, the predetermined even during fuel cut Controller matter is compared to a situation where not established lower the rotational speed the fuel cut operation.

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