JP2013245639A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine which when switching from a driving state of the internal combustion engine to a driven state, can surely suppress shock to a vehicle.SOLUTION: A control device for an internal combustion engine performs fuel cut after attenuating output torque of an engine when a fuel cut performance condition is satisfied. The control device for the internal combustion engine includes an EG-ECU which sets a second attenuation term T2 including a period for switching an operation state of the engine from a driving state to a driven state when attenuating the output torque and attenuates the output torque at a predetermined attenuation rate ΔTQ2 during the second attenuation term T2. On the condition where an air conditioning unit is in an active state or during cold, the EG-ECU sets the second attenuation term T2 longer than the second attenuation term T2 which is set during a normal time in which the air conditioning unit is in an inactive state, and during non-cold.

Description

  The present invention relates to a control device for an internal combustion engine.

  In general, in a vehicle including an internal combustion engine as a drive source, so-called fuel cut is performed in which fuel supply to the internal combustion engine is stopped when a predetermined condition is satisfied such as when the vehicle is decelerated in order to improve fuel efficiency. However, at the start of such fuel cut, the torque generated by the internal combustion engine suddenly decreases or disappears, and a torque shock due to the torque step occurs.

  Therefore, conventionally, as a control device for an internal combustion engine for the purpose of reducing such torque shock, a fuel cut is started after the generated torque of the internal combustion engine is attenuated by gradually retarding the ignition timing in advance. What was made into is known (for example, refer patent document 1). According to this control device for an internal combustion engine, the torque step at the start of fuel cut is reduced, and torque shock is suppressed.

Japanese Patent Laid-Open No. 10-030477

  However, in the control device for a conventional internal combustion engine described in Patent Document 1 described above, even if the generated torque of the internal combustion engine is attenuated prior to the fuel cut, it is caused by the following factors that are generated at the time of the fuel cut transition or the like. Until the shock, the occurrence cannot be reliably suppressed.

  That is, at the time of shifting to the fuel cut, the torque generated by the internal combustion engine is attenuated, so that at a certain point in time, the drive torque is driven by the torque generated by the internal combustion engine, and the input torque input from the drive wheel. To switch to a driven state in which the internal combustion engine is driven. At the time of switching from the driven state to the driven state, the torsional torque of the power transmission system is released, and a reverse torque is applied to the power transmission system, causing a problem that the vehicle is shocked.

  Such a shock is generated due to a torque step between the torque generated by the internal combustion engine and the input torque from the drive wheel at the time of the switching, and becomes larger as the torque step becomes larger.

  The present invention has been made in view of the above circumstances, and provides an internal combustion engine control device that can reliably suppress a shock to a vehicle when the internal combustion engine is switched from a driven state to a driven state. The purpose is to do.

  In order to achieve the above object, the control apparatus for an internal combustion engine according to the present invention (1) attenuates the output torque of the internal combustion engine and supplies fuel to the internal combustion engine when a predetermined predetermined fuel cut execution condition is satisfied. In the control apparatus for an internal combustion engine that executes a fuel cut to stop the operation, a period during which the operating state of the internal combustion engine switches from a driving state that generates driving force to a driven state that receives driving force when the output torque is attenuated is included. Control means for setting an operating state switching period and attenuating the output torque at a predetermined predetermined damping rate during the operating state switching period, the control means being driven by the output of the internal combustion engine On condition that the air conditioner is in an operating state or when the internal combustion engine is cold, the operation state switching period is set to the non-operating state of the air conditioner and Serial has a configuration that is set longer than the operating state switching period set at between non cold engine.

  With this configuration, the control device for an internal combustion engine according to the present invention provides a period during which the operation state of the internal combustion engine is switched from the drive state to the driven state on condition that the air conditioner is in an operating state or when the internal combustion engine is cold. The operation state switching period that includes the air conditioner is set to be longer than the operation state switching period that is set when the air conditioner is not operating and when it is not cold.

  Here, in order to suppress a shock that occurs when the internal combustion engine is switched from the driving state to the driven state, it is desirable that the switching be performed during the operation state switching period. The timing of such switching is estimated by a drive switching torque estimated based on predetermined parameters including the auxiliary machine load of the auxiliary machines including the air conditioner and the cooling water temperature of the internal combustion engine. However, when the air conditioner is operating or when the internal combustion engine is cold, there may be a difference between the estimated drive switching torque and the actual drive switching torque. In this case, the timing of switching from the driving state of the internal combustion engine to the driven state may be outside the operating state switching period, and the shock at the time of switching cannot be reliably suppressed.

  As described above, the control device for an internal combustion engine according to the present invention sets the operation state switching period when the air conditioner is not operating and when the air conditioner is cold, on condition that the air conditioner is operating or when the internal combustion engine is cold. Therefore, even when the actual drive switching torque deviates from the estimated drive switching torque, the timing of switching from the driving state of the internal combustion engine to the driven state is set. It can be accommodated within the long operating state switching period. Therefore, the shock to the vehicle at the time of switching from the driving state of the internal combustion engine to the driven state can be reliably suppressed.

  The control apparatus for an internal combustion engine according to the present invention is the control apparatus for an internal combustion engine according to (1), wherein (2) the control means performs the predetermined attenuation rate before the start of the operation state switching period. A driving torque attenuation period for attenuating the output torque over a natural number times the natural vibration period of the power transmission system interposed between the internal combustion engine and the drive wheel at a higher attenuation rate, After the operation state switching period ends, a driven torque attenuation period in which the output torque is attenuated over a natural number times the natural vibration period of the power transmission system at a higher attenuation rate than the predetermined attenuation rate. It has a configuration to set.

  With this configuration, the control device for an internal combustion engine according to the present invention intervenes between the internal combustion engine and the drive wheel at a damping rate higher than a predetermined damping rate during the driving state switching period before the start of the driving state switching period. A driving torque attenuation period is set in which the output torque is attenuated over a natural number times the natural vibration period of the power transmission system. As a result, it is possible to suppress so-called squealing in which the vehicle vibrates in the front-rear direction, which is generated by significantly reducing the attenuation rate of the output torque of the internal combustion engine during the operation state switching period.

  In addition, the control device for an internal combustion engine according to the present invention provides power transmission that is interposed between the internal combustion engine and the drive wheels at a damping rate higher than a predetermined damping rate during the driving state switching period after the driving state switching period ends. A driven torque decay period is set for attenuating the output torque over a natural number of times the natural vibration period of the system. As a result, it is possible to suppress the squealing that occurs when the fuel supply is stopped after the driven torque decay period.

  The control apparatus for an internal combustion engine according to the present invention is the control apparatus for an internal combustion engine according to (1) or (2), wherein (3) the control means is configured such that the operation state of the internal combustion engine is changed from the drive state. A drive switching torque at the time of switching to the driving state is estimated, and in the driving state switching period, the starting torque that is higher by a minute torque than the driving switching torque is lower by the minute torque than the driving switching torque. The output torque is attenuated at the predetermined attenuation rate up to the end torque.

  With this configuration, the control device for an internal combustion engine according to the present invention can control the timing of switching from the driving state of the internal combustion engine to the driven state at the center of the operating state switching period. That is, in the operation state switching period, the period before and after the switching timing can be made equal. Thereby, for example, even when the actual drive switching torque is shifted in any direction of increase / decrease with respect to the estimated drive switching torque, the switching timing can be kept within the operation state switching period. Therefore, even if a slight shift occurs in the actual drive switching torque, it is possible to reliably suppress a shock to the vehicle at the time of the switching.

  The internal combustion engine control device according to the present invention is the internal combustion engine control device according to any one of (1) to (3), wherein (4) the drive switching torque is a load of the air conditioner, a cooling of the internal combustion engine. It is estimated based on predetermined parameters including the water temperature.

  With this configuration, in the control apparatus for an internal combustion engine according to the present invention, the drive switching torque is estimated based on predetermined parameters including the load of the air conditioner and the cooling water temperature of the internal combustion engine. An error in estimating the switching torque may increase. That is, the actual drive switching torque may deviate from the estimated drive switching torque. The control device for an internal combustion engine according to the present invention sets the operating state switching period longer when the air conditioner is operating or when it is cold, so that when the actual driving switching torque deviates from the estimated driving switching torque Even so, the timing of switching from the driving state of the internal combustion engine to the driven state can be kept within the set operating state switching period. Therefore, the shock to the vehicle at the time of switching from the driving state of the internal combustion engine to the driven state can be reliably suppressed.

  An internal combustion engine control apparatus according to the present invention is the internal combustion engine control apparatus according to any one of (1) to (4), wherein (5) the control means is configured to control an intake air amount and an ignition timing for the internal combustion engine. The output torque is attenuated by varying at least one.

  With this configuration, the control device for an internal combustion engine according to the present invention can adjust the attenuation rate of the output torque of the internal combustion engine.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the internal combustion engine which can suppress reliably the shock with respect to the vehicle at the time of switching from the drive state of an internal combustion engine to a driven state can be provided.

1 is a schematic configuration diagram of a vehicle to which a control device for an internal combustion engine according to an embodiment of the present invention is applied. 1 is a schematic configuration diagram of an engine according to an embodiment of the present invention. 1 is a schematic perspective view of an engine according to an embodiment of the present invention. 1 is a skeleton diagram of an automatic transmission according to an embodiment of the present invention. It is a time chart which shows an example of the control aspect at the time of the fuel cut transfer in embodiment of this invention. It is a figure explaining the setting aspect of the length of the 2nd attenuation | damping period in embodiment of this invention. It is a flowchart which shows the output torque attenuation operation by the engine electronic control unit which comprises the control apparatus of the internal combustion engine which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the following description, an example in which the control device for an internal combustion engine according to the present invention is applied to an FR (Front engine Rear drive) vehicle equipped with an automatic transmission will be described.

  As shown in FIG. 1, a vehicle 1 according to the present embodiment includes an engine 2 constituting an internal combustion engine, a torque converter 3 that amplifies output torque output from the engine 2, and a rotational speed of an output shaft of the torque converter 3. The transmission mechanism 5 that rotates the output shaft 4 at the rotational speed obtained by shifting the transmission shaft 4, the differential gear 7 that transmits the rotational force of the output shaft 4 of the transmission mechanism 5 to the drive shafts 6 L and 6 R, and the drive shafts 6 L and 6 R are rotated. The driving wheels 8L and 8R that are driven by this are provided. Here, the torque converter 3 and the transmission mechanism 5 constitute an automatic transmission 9.

  Further, the vehicle 1 electrically connects an engine electronic control unit (hereinafter referred to as “EG-ECU”) 10 that controls the engine 2, a hydraulic control circuit 11 that controls the automatic transmission 9 by hydraulic pressure, and a hydraulic control circuit 11. Automatic transmission electronic control unit (hereinafter referred to as “TM-ECU”) 12, air conditioning unit 13, and air conditioner electronic control unit (hereinafter referred to as “A / C-ECU”) for controlling air conditioning unit 13. 14).

  As shown in FIG. 2, the engine 2 includes a cylinder block 20, a cylinder head 21 fixed to the upper part of the cylinder block 20, and an oil pan 22 that stores oil, and the cylinder block 20, the cylinder head 21, Thus, a plurality of cylinders 23 are formed.

  In the present embodiment, the engine 2 is assumed to be an in-line 4-cylinder engine. However, in the present invention, the in-line 6-cylinder engine, the V-type 6-cylinder engine, the V-type 12-cylinder engine, or the horizontal You may be comprised by various types of engines, such as an opposed 6 cylinder engine. Note that the engine 2 shown in FIG. 2 shows one cylinder 23 among four cylinders arranged in series.

  A piston 24 is accommodated in the cylinder 23 so as to be able to reciprocate. A combustion chamber 25 of each cylinder 23 is formed by the cylinder block 20, the cylinder head 21, and the piston 24. In the present embodiment, the engine 2 is described as being constituted by a four-cycle engine that performs a series of four strokes including an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke while the piston 24 reciprocates twice. To do.

  Pistons 24 housed in the cylinders 23 are connected to a crankshaft 27 via connecting rods 26. The connecting rod 26 converts the reciprocating motion of the piston 24 into the rotational motion of the crankshaft 27.

  Therefore, the engine 2 reciprocates the piston 24 by burning the fuel / air mixture in the combustion chamber 25 and rotates the crankshaft 27 via the connecting rod 26, thereby supplying power to the torque converter 3. To communicate.

  In addition, although the fuel used for the engine 2 is gasoline, it may replace with gasoline and may be alcohol fuel which mixed alcohol and gasoline, such as hydrocarbon fuels, such as light oil, and ethanol.

  The engine 2 is provided with an intake pipe 30 connected to the cylinder head 21 for introducing air into the combustion chamber 25. The intake pipe 30 includes an air cleaner 31 that cleans air flowing from outside the vehicle, an air flow sensor 32 that detects a flow rate of air introduced into the combustion chamber 25, that is, an intake air amount, and a throttle valve that adjusts the intake air amount. 33 is provided.

  The air cleaner 31 is configured to remove foreign substances in the intake air by using, for example, a paper or synthetic fiber nonwoven fabric filter accommodated therein. The air flow sensor 32 is provided on the upstream side of the throttle valve 33 and outputs a detection signal indicating the intake air amount to the EG-ECU 10.

  The throttle valve 33 is constituted by a thin disc-like valve body, and includes a shaft at the center of the valve body. The throttle valve 33 is provided with a throttle valve actuator 34 that rotates the valve body by rotating the shaft in accordance with the control of the EG-ECU 10 and adjusts the intake air amount to the throttle valve 33.

  Further, the engine 2 is provided with an exhaust pipe 35 connected to the cylinder head 21 for discharging exhaust gas generated by combustion of the air-fuel mixture in the combustion chamber 25 to the outside of the vehicle. The exhaust pipe 35 is provided with a catalyst 36 for oxidation-reduction purification of harmful substances in the exhaust gas.

  The catalyst 36 generally includes a three-way catalyst that can efficiently remove harmful substances such as unburned hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxide (NOx) contained in the exhaust gas. Yes. As this three-way catalyst, a catalyst having a function of efficiently removing NOx even from exhaust gas having a high NOx content is preferably used.

  The cylinder block 20 is formed with a water jacket 37 through which cooling water circulates, and a water temperature sensor 38 that detects the temperature of the cooling water circulated through the water jacket 37. The cylinder head 21 is formed with an intake port 40 for communicating the intake pipe 30 and the combustion chamber 25 and an exhaust port 41 for communicating the combustion chamber 25 and the exhaust pipe 35.

  Further, the cylinder head 21 has an intake valve 42 for controlling the introduction of combustion air from the intake pipe 30 to the combustion chamber 25 and an exhaust valve for controlling the discharge of exhaust gas from the combustion chamber 25 to the exhaust pipe 35. An exhaust valve 43, an injector 44 for injecting fuel into the combustion chamber 25, and a spark plug 45 for igniting the air-fuel mixture in the combustion chamber 25 are provided.

  The injector 44 has a solenoid coil and a needle valve that are controlled by the EG-ECU 10. Fuel is supplied to the injector 44 at a predetermined pressure. When the solenoid coil is energized by the EG-ECU 10, the injector 44 opens the needle valve and injects fuel into the combustion chamber 25.

  The spark plug 45 is a known spark plug having an electrode made of platinum or an iridium alloy. The spark plug 45 is discharged when the electrode is energized by the EG-ECU 10 and ignites the air-fuel mixture in the combustion chamber 25.

  As shown in FIG. 3, the engine 2 is provided with an intake camshaft 50 and an exhaust camshaft 51 rotatably on the cylinder head 21. The intake camshaft 50 is provided with an intake cam 52 that contacts the upper end of the intake valve 42. When the intake camshaft 50 rotates, the intake cam 52 drives the intake valve 42 to open and close, so that the intake port 40 and the combustion chamber 25 are opened and closed.

  The exhaust camshaft 51 is provided with an exhaust cam 53 that contacts the upper end of the exhaust valve 43. When the exhaust camshaft 51 rotates, the exhaust cam 53 opens and closes the exhaust valve 43 so that the combustion chamber 25 and the exhaust port 41 are opened and closed.

  At one end of the intake camshaft 50, an intake cam sprocket 54 and an intake side rotation phase controller 55 that rotates the intake camshaft 50 relative to the intake cam sprocket 54 are provided.

  The intake side rotation phase controller 55 is controlled by the EG-ECU 10 to rotate the intake camshaft 50 forward or retarded with respect to the intake cam sprocket 54.

  An exhaust cam sprocket 56 and an exhaust side rotation phase controller 57 that rotates the exhaust cam shaft 51 relative to the exhaust cam sprocket 56 are provided at one end of the exhaust cam shaft 51.

  Further, the exhaust-side rotation phase controller 57 is controlled by the EG-ECU 10 to rotate the exhaust camshaft 51 forward or retarded with respect to the exhaust cam sprocket 56.

  A crank sprocket 58 is provided at one end of the crankshaft 27. A timing belt 59 is wound around the intake cam sprocket 54, the exhaust cam sprocket 56, and the crank sprocket 58. The timing belt 59 transmits the rotation of the crank sprocket 58 to the intake cam sprocket 54 and the exhaust cam sprocket 56.

  Accordingly, when the rotation of the crankshaft 27 is transmitted to the intake camshaft 50 and the exhaust camshaft 51 by the timing belt 59, the intake valve 42 and the exhaust valve 43 driven by the intake camshaft 50 and the exhaust camshaft 51 are The intake port 40 and the exhaust port 41 are opened and closed in synchronization with the crankshaft 27, respectively. The intake camshaft 50 and the exhaust camshaft 51 make one round while the crankshaft 27 makes two rounds.

  The crankshaft 27 is provided with a crank rotor 60 that rotates together with the crankshaft 27. The engine 2 includes a crank angle sensor 61 for detecting the rotation angle of the crank rotor 60.

  The crank angle sensor 61 is configured by an MRE sensor having a magnetic resistance element (MRE). When the crankshaft 27 rotates, the direction of the magnetic field applied to the crank angle sensor 61, that is, the magnetic vector, changes due to the crests and valleys of the teeth provided in the crank rotor 60, and the internal resistance value changes.

  The crank angle sensor 61 generates a crank angle signal shaped into a rectangular wave that takes a high state and a low state by comparing a waveform output after converting the change in resistance value into a voltage and a threshold value. The generated crank angle signal is output to the EG-ECU 10.

  As shown in FIG. 4, the torque converter 3 includes a pump impeller 71 connected to the crankshaft 27 of the engine 2 via the input shaft 70, and an output shaft 72 constituting a part of the input shaft of the transmission mechanism 5. And a stator impeller 75 that is prevented from rotating in one direction by a one-way clutch 74. Here, the pump impeller 71 and the turbine impeller 73 transmit power through a fluid.

  The torque converter 3 has a lockup clutch 76 for directly connecting the pump impeller 71 and the turbine impeller 73. The lock-up clutch 76 holds a front cover (not shown) with hydraulic fluid when the vehicle 1 is traveling at high speed, and mechanically directly connects the pump impeller 71 and the turbine impeller 73 via the lock-up damper 77. It is supposed to take a joint state.

  As described above, the lock-up clutch 76 takes the power from the engine 2 to the speed change mechanism 5 as compared with the released state in which the pump impeller 71 and the turbine impeller 73 are mechanically released by taking the engaged state. To improve the transmission efficiency.

  The pump impeller 71 is provided with a mechanical oil pump 78 that generates a hydraulic pressure for controlling the transmission of the transmission mechanism 5 and a hydraulic pressure for supplying lubricating oil to each part.

  The transmission mechanism 5 includes a first planetary gear device 79, a second planetary gear device 80, and a third planetary gear device 81. The sun gear S1 of the first planetary gear unit 79 can be connected to the input shaft via the clutch C3 and can be connected to the housing 82 via the one-way clutch F2 and the brake B3.

  The carrier CA1 of the first planetary gear device 79 can be connected to the housing 82 via the brake B1. The ring gear R1 of the first planetary gear device 79 is connected to the ring gear R2 of the second planetary gear device 80, and can be connected to the housing 82 via the brake B2.

  The sun gear S2 of the second planetary gear device 80 is connected to the sun gear S3 of the third planetary gear device 81, and can be connected to the input shaft via the clutch C4. The sun gear S2 can be connected to the input shaft via the one-way clutch F4 and the clutch C1.

  The carrier CA2 of the second planetary gear device 80 is connected to the ring gear R3 of the third planetary gear device 81, and can be connected to the input shaft via the clutch C2 and to the housing 82 via the brake B4. It has become.

  The carrier CA2 is prevented from rotating in the direction opposite to the rotation direction of the input shaft by a one-way clutch F3 provided in parallel with the brake B4. Further, the carrier CA3 of the third planetary gear device 81 is connected to the output shaft 4.

  The clutches C1 to C4 and the brakes B1 to B4 are configured by a hydraulic friction engagement device that is controlled to be engaged by a hydraulic actuator, such as a multi-plate clutch or brake.

  The hydraulic control circuit 11 includes transmission solenoids S1 to S4 and linear solenoids SLT and SLU. The transmission solenoid S1 is operated at the time of shifting from the first speed to the second speed. The transmission solenoid S2 is operated at the time of shifting from the 2nd speed to the 3rd speed and at the time of shifting from the 5th speed to the 6th speed.

  The transmission solenoid S3 is operated when shifting from the third speed to the fourth speed. The transmission solenoid S4 is operated at the time of shifting from the fourth speed to the fifth speed.

  The linear solenoid SLT performs line pressure control and back pressure control of an accumulator (not shown). The linear solenoid SLU mainly controls the state of the lockup clutch 76.

  As described above, the clutches C1 to C4 and the brakes B1 to B4 are engaged according to the hydraulic circuit that is switched according to the excitation state or non-excitation of the transmission solenoids S1 to S4 and the linear solenoids SLT and SLU or the operating state of the manual valve (not shown). One of the state and the release state is assumed.

  That is, the speed change mechanism 5 is configured to take a gear position according to the combination of the engaged state and the released state of the clutches C1 to C4 and the brakes B1 to B4. In the present embodiment, the speed change mechanism 5 is assumed to form any one of six forward speeds and one reverse speed that is composed of first to sixth speeds.

  In FIG. 1, an EG-ECU 10 is a microprocessor that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, and an input / output port (not shown). It is configured.

  A program for causing the microprocessor to function as the EG-ECU 10 is stored in the ROM of the EG-ECU 10. That is, the CPU of the EG-ECU 10 functions as the EG-ECU 10 by executing a program stored in the ROM using the RAM as a work area.

  In the present embodiment, on the input side of the EG-ECU 10, in addition to the crank angle sensor 61, the airflow sensor 32, and the water temperature sensor 38, an accelerator opening sensor 91 that detects an accelerator opening representing the opening of the accelerator pedal 90 is provided. Are connected to a vehicle speed sensor 92 for detecting the vehicle speed.

  The accelerator opening sensor 91 is configured by, for example, an electronic position sensor using a Hall element. When the accelerator pedal 90 is operated by the driver, the accelerator opening sensor 91 outputs a signal indicating the accelerator opening indicating the opening of the accelerator pedal 90 to the EG-ECU 10.

  The vehicle speed sensor 92 detects the rotation angles of the drive shafts 6L and 6R, and outputs a signal representing the vehicle speed obtained by averaging the detected rotation angles of the drive shafts 6L and 6R to the EG-ECU 10.

  The EG-ECU 10 communicates with other ECUs such as the TM-ECU 12 and the A / C-ECU 14 via the high-speed CAN, and performs various controls with other ECUs such as the TM-ECU 12 and the A / C-ECU 14. Signals and data are exchanged.

  For example, the EG-ECU 10 controls the fuel injection control for the injector 44, the ignition control for the spark plug 45, and the intake air amount for the throttle valve actuator 34 based on detection signals input from various sensors that detect the operating state of the engine 2. While performing operation control of the engine 2 such as adjustment control, data related to the operation state of the engine 2 is output to the TM-ECU 12 as necessary.

  Further, as part of engine control, the EG-ECU 10 executes a fuel cut that stops the supply of fuel to the engine 2 when a predetermined fuel cut execution condition established in advance during deceleration of the vehicle 1 is satisfied. . For example, the fuel cut execution condition is that the rotational speed of the engine 2 is equal to or higher than a predetermined fuel cut reference rotational speed and that the opening of the accelerator pedal 90 is 0, that is, the accelerator is OFF. This fuel cut is performed by stopping or limiting the fuel injection from the injector 44. Note that the EG-ECU 10 ends the fuel cut when the speed of the engine 2 becomes less than the fuel cut reference speed during execution of the fuel cut or when the fuel cut end condition is satisfied when the accelerator pedal 90 is depressed. It is supposed to be.

  Further, the EG-ECU 10 controls the intake side rotational phase controller 55 and the exhaust cam sprocket 56 to adjust the opening / closing timing of the intake valve 42 and the exhaust valve 43 according to the operating state of the engine 2. Control is to be executed.

  The TM-ECU 12 is configured by a microprocessor that includes a CPU, a ROM, a RAM, a flash memory, and an input / output port (not shown). A program for causing the microprocessor to function as the TM-ECU 12 is stored in the ROM of the TM-ECU 12.

  That is, the CPU of the TM-ECU 12 functions as the TM-ECU 12 by executing a program stored in the ROM using the RAM as a work area.

  In the present embodiment, a shift position sensor 94 that detects the shift position selected by the shift lever 93 is connected to the input side of the TM-ECU 12.

  The TM-ECU 12 communicates with other ECUs such as the EG-ECU 10 and the A / C-ECU 14 via the high-speed CAN, and performs various controls with other ECUs such as the EG-ECU 10 and the A / C-ECU 14. Signals and data are exchanged.

  For example, the TM-ECU 12 controls the hydraulic control circuit 11 based on the shift position detected by the shift position sensor 94 and the operating state of the engine 2 output from the EG-ECU 10, so Are formed, and information representing the speed stage formed in the speed change mechanism 5 is output to the EG-ECU 10.

  The air conditioning unit 13 is housed in the engine room of the vehicle 1, and includes a compressor 101 as a compressor, a condenser 102 as a condenser, an expansion valve 103 as a decompression unit, and an evaporator 104 as a heat exchanger. It has. The compressor 101, the condenser 102, the expansion valve 103, and the evaporator 104 are communicated with each other through the refrigerant circulation path 100, and the refrigeration cycle is executed by circulating the refrigerant through the refrigerant circulation path 100. As the refrigerant, for example, an antifreeze liquid used as engine cooling water is used. Note that a gas such as carbon dioxide may be used as the refrigerant instead of the antifreeze liquid. The air conditioning unit 13 according to the present embodiment constitutes an air conditioner according to the present invention.

  The compressor 101 compresses the refrigerant in the low pressure gas phase state and discharges it in the high temperature and high pressure superheated gas phase state. The compressor 101 is connected to the crankshaft 27 of the engine 2 via a drive belt 105 and a pulley 106. Therefore, when the crankshaft 27 rotates, the compressor 101 is driven by the driving force output from the engine 2. Therefore, when the air conditioning unit 13 is in an operating state, that is, when the compressor 101 is being driven, the driving torque of the compressor 101 at this time is the engine 2 as an external load (auxiliary load), that is, a load of the air conditioning unit 13. Act on.

  The compressor 101 is a variable displacement compressor. The variable capacity compressor 101 adjusts the refrigerant suction pressure by changing the stroke of the piston by changing the current value of the energization current to the solenoid by the A / C-ECU 14 (to be described later) or changing the duty ratio. ing.

  The condenser 102 is connected to the downstream side of the compressor 101 in the refrigerant circuit 100, and is disposed, for example, on the front surface of the radiator. The condenser 102 is configured to cool the superheated gas phase refrigerant discharged from the compressor 101 to the condensation point by a vehicle wind during driving or a wind of a cooling electric fan (not shown) to a liquid phase state.

  The expansion valve 103 is disposed downstream of the capacitor 102, and depressurizes the liquid-phase refrigerant that has flowed out of the capacitor 102 to a low-pressure liquid-phase state.

  The evaporator 104 evaporates the low-pressure liquid phase refrigerant that has flowed out of the expansion valve 103 into a low-pressure gas-phase state, and constitutes an evaporator. The evaporator 104 is disposed in an air conditioning duct (not shown) that communicates between the interior and exterior of the vehicle. The evaporator 104 cools the air-conditioning air by exchanging heat between the refrigerant circulating in the refrigerant circuit 100 and the air-conditioning air sucked into the air-conditioning duct and passing through the evaporator 104. .

  The A / C-ECU 14 is configured by a microprocessor having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, and an input / output port (not shown). ing.

  A program for causing the microprocessor to function as the A / C-ECU 14 is stored in the ROM of the A / C-ECU 14. That is, when the CPU of the A / C-ECU 14 executes a program stored in the ROM using the RAM as a work area, the microprocessor functions as the A / C-ECU 14.

  In the present embodiment, various sensors such as a pressure sensor 107 and a refrigerant temperature sensor 108 are connected to the input side of the A / C-ECU 14. The pressure sensor 107 is installed on the downstream side of the compressor 101 in the refrigerant circuit 100, detects the pressure of the high-pressure superheated refrigerant, and supplies a voltage corresponding to the detected pressure to the A / C-ECU 14. It is designed to output. The refrigerant temperature sensor 108 is provided in the evaporator 104, detects the refrigerant temperature, and outputs a signal corresponding to the detected refrigerant temperature to the A / C-ECU 14. Further, the above-described compressor 101 and a blower motor (not shown) are connected to the output side of the A / C-ECU 14.

  The A / C-ECU 14 communicates with other ECUs such as the EG-ECU 10 and the TM-ECU 12 via the high-speed CAN, and various control signals and other ECUs such as the EG-ECU 10 and the TM-ECU 12 It is designed to exchange data.

  The A / C-ECU 14 is supplied with switch signals from switches on a control panel provided on the front surface of the vehicle interior. Here, each switch on the control panel includes an air conditioner (A / C) switch for instructing to drive and stop the compressor 101, a temperature setting switch for setting the temperature in the passenger compartment to a desired temperature, Examples include an air volume switching switch for switching the air volume, and an air outlet switching switch for switching the air outlet mode.

  The A / C-ECU 14 controls the rotational speed of a blower fan (not shown), for example, by driving a blower motor in accordance with signals input from the above-described various sensors, switches, and the like. Controls the airflow (blower airflow) of the conditioned air blown out.

  Next, fuel cut executed by the EG-ECU 10 according to the present embodiment will be described. The EG-ECU 10 executes a fuel cut that stops the fuel supply to the engine 2 after the output torque of the engine 2 is attenuated.

  Specifically, as shown in FIG. 5, the EG-ECU 10 determines that the accelerator pedal 90 of the accelerator pedal 90 is operated by the accelerator opening sensor 91 at time t0 when the rotational speed of the engine 2 is equal to or higher than a predetermined fuel cut reference rotational speed. The output torque of the engine 2 is attenuated from a predetermined delay section, for example, from time t1 when about 100 ms to 200 ms have elapsed after detecting that the opening degree is 0, that is, the accelerator is OFF. .

  Here, in the present embodiment, the EG-ECU 10 has a period during which the operating state of the engine 2 switches from a driving state that generates driving force to a driven state that receives driving force when the output torque of the engine 2 is attenuated. A second decay period T2 is set. The second decay period T2 in the present embodiment corresponds to the operation state switching period in the present invention.

  Further, the EG-ECU 10 sets a first damping period T1 in which the output torque of the engine 2 is attenuated from the initial torque before the start of the second damping period T2, and the output torque of the engine 2 after the end of the second damping period T2. Is set to a third attenuation period T3 for attenuating to a torque for stopping fuel supply to the engine 2. The first decay period T1 in the present embodiment corresponds to the driving torque decay period in the present invention, and the second decay period T2 corresponds to the driven torque decay period in the present invention.

  Therefore, the EG-ECU 10 attenuates the output torque of the engine 2 in the first attenuation period T1, the second attenuation period T2, and the third attenuation period T3.

  Here, the ROM of the EG-ECU 10 has a map in which the output torque of the engine 2 is previously associated with the engine rotation speed, the intake air amount, and the ignition timing for the spark plug 45 by experiments. Stored.

  The EG-ECU 10 corresponds to a map with respect to the engine speed of the engine 2 obtained from the signal output from the crank angle sensor 61, the intake air amount obtained from the air flow sensor 32, and the ignition timing for the spark plug 45. By specifying the attached output torque of the engine 2, the current output torque of the engine 2 (hereinafter referred to as “current torque TQc”) is estimated.

  Further, the EG-ECU 10 attenuates the output torque of the engine 2 so that the operating state of the engine 2 is changed from a driving state that generates driving force to a driven state that receives a driving force such as the inertial force of the vehicle 1. The output torque of the engine 2 to be switched (hereinafter referred to as “drive switching torque TQex”) is estimated.

  Here, the drive switching torque TQex is estimated based on predetermined parameters including a load of the air conditioning unit 13 (hereinafter referred to as an air conditioner load) and a coolant temperature of the engine 2 (hereinafter referred to as “cooling water temperature”). It has become.

  Specifically, the ROM of the EG-ECU 10 stores the vehicle speed, the gear stage formed in the transmission mechanism 5, auxiliary loads such as the air conditioning unit 13, the alternator and the oil pump, and the cooling water temperature of the engine 2. Thus, a map in which the drive switching torque TQex is previously correlated by experiment is stored.

  The EG-ECU 10 includes a vehicle speed of the vehicle 1 obtained from the vehicle speed sensor 92, a gear stage formed in the transmission mechanism 5 obtained from the TM-ECU 12, an auxiliary machine load corresponding to the operating state of each auxiliary machine, and a water temperature sensor. The drive switching torque TQex can be estimated by specifying the drive switching torque TQex associated with the map with respect to the cooling water temperature obtained from 38.

  Further, the EG-ECU 10 determines the engine 2 at the start of the second attenuation period T2 based on the predetermined attenuation rate ΔTQ2 in the second attenuation period T2 and the length L2 of the second attenuation period T2. A minute torque TQm that is a difference between the output torque and the drive switching torque TQex is calculated by the following mathematical formula.

  TQm = ΔTQ2 × L2 / 2

  At time t1, the EG-ECU 10 presents the output torque of the engine 2 with the start torque TQex + TQm that is higher than the drive switching torque TQex by a minute torque TQm that is a predetermined number N · m as a target torque. The torque TQc is attenuated.

  Specifically, the EG-ECU 10 takes a natural number times the natural vibration period Tu of the power transmission system interposed between the engine 2 and the drive wheels 8L and 8R at a predetermined attenuation rate ΔTQ1. The output torque attenuation control for attenuating the output torque of the engine 2 from the current torque TQc to the target torque TQt (in this embodiment, the start torque TQex + TQm) is executed. Here, the attenuation rate ΔTQ1 determined in the first attenuation period T1 is higher than the attenuation rate ΔTQ2 in the second attenuation period T2, which will be described later. Further, the natural vibration period Tu of the power transmission system interposed between the engine 2 and the drive wheels 8L and 8R is determined in advance for each shift stage formed in the transmission mechanism 5 by experiments.

  In the present embodiment, as shown in FIG. 5, the EG-ECU 10 attenuates the output torque of the engine 2 by changing the ignition timing for the engine 2 to the retard side.

  Further, the EG-ECU 10 executes output torque attenuation control at time t1, and when the output torque of the engine 2 reaches the target torque at time t2, the output torque attenuation rate of the engine 2 is negative in the second attenuation period T2. The attenuation factor ΔTQ2 is reduced to such an extent that it does not become. That is, the generated torque of the engine 2 is controlled so as to reduce the gradient of the generated torque of the engine 2 in accordance with the timing when the operating state of the engine 2 switches from the driven state to the driven state.

  In the second decay period T2, the EG-ECU 10 starts from a start torque TQex + TQm that is higher by a minute torque TQm than the drive switching torque TQex and ends at a torque TQex-TQm that is lower by a minute torque TQm than the drive switching torque TQex. The output torque of the engine 2 is attenuated.

  Further, the EG-ECU 10 attenuates the output torque of the engine 2 from the time t2 by the attenuation rate ΔTQ2, and when the output torque of the engine 2 reaches the end torque TQex-TQm at the time t3, the fuel supply to the engine 2 is stopped. Using the torque TQfc of the engine 2 as a target torque, the output torque of the engine 2 is attenuated.

  Specifically, the EG-ECU 10 takes a natural number times the natural vibration period Tu of the power transmission system interposed between the engine 2 and the drive wheels 8L and 8R at a predetermined attenuation rate ΔTQ3. The output torque attenuation control for attenuating the output torque of the engine 2 from the end torque TQex-TQm to the target torque TQfc is executed. Here, the attenuation rate ΔTQ3 determined in the third attenuation period T3 is higher than the attenuation rate ΔTQ2 in the second attenuation period T2 described above. Further, the natural vibration period Tu of the power transmission system interposed between the engine 2 and the drive wheels 8L and 8R is determined in advance for each shift stage formed in the transmission mechanism 5 by experiments.

  Further, the EG-ECU 10 attenuates the output torque of the engine 2 from the time t3 by the attenuation rate ΔTQ3, and controls the injector 44 so that the fuel is not injected when the output torque of the engine 2 reaches the target torque at the time t4. It has become.

  As described above, the EG-ECU 10 executes the output torque attenuation control in the first attenuation period T1, thereby causing the output torque attenuation rate of the engine 2 in the second attenuation period T2 without causing a shock to the vehicle 1. It is configured to suppress the sneezing that occurs due to a significant decrease.

  Further, the EG-ECU 10 switches the operating state of the engine 2 from the driving state to the driven state by significantly reducing the damping rate of the output torque of the engine 2 to a level that does not become negative in the second damping period T2. It is configured to prevent shocks that sometimes occur in the power transmission system.

  Further, the EG-ECU 10 performs the output torque attenuation control in the third attenuation period T3, so that the vehicle 1 does not generate a shock and stops the fuel injection by the injector 44 at time t4. It is comprised so that it may suppress.

  Next, a method for setting the length L2 of the second attenuation period T2 described above will be described with reference to FIG.

  In the present embodiment, the second decay period T2 is provided to prevent a shock that occurs in the power transmission system when the operating state of the engine 2 switches from the driving state to the driven state as described above. Is. Therefore, if the timing for switching from the driving state to the driven state does not fall within the second attenuation period T2, it is impossible to prevent a shock at the time of switching.

  Here, the timing of switching from the drive state to the driven state is estimated based on the estimated drive switching torque TQex. Specifically, as shown in FIG. 6A, the intersection of a thick broken line indicating the estimated drive switching torque TQex and a thick solid line indicating the output torque of the engine 2 is estimated as the switching timing.

  However, in FIG. 6A, the actual drive switching torque indicated by a thin solid line does not necessarily coincide with the estimated drive switching torque TQex, and the estimated drive switching torque TQex and the actual drive switching torque TQex shown in FIG. There may be a deviation from the drive switching torque.

  For example, the air conditioner load when the air conditioning unit 13 is activated (when the air conditioner is ON) is obtained as a compatible constant using, for example, the temperature and pressure of the refrigerant, but variations in manufacturing the pressure sensor 107, the refrigerant temperature sensor 108, etc. An error may occur in the air conditioner load calculated due to the above. In addition, the engine friction in the cold state is obtained as a compatible constant using the cooling water temperature of the engine 2 or the engine oil temperature. However, a viscosity change occurs due to oil deterioration, or the oil type is changed by the user. Then, a deviation may occur between the calculated engine friction and the actual engine friction.

  For this reason, an error in estimating the drive switching torque TQex may be large when the air conditioner is ON or cold. As a result, a deviation occurs between the estimated drive switching torque TQex and the actual drive switching torque.

  As described above, when a deviation occurs between the estimated drive switching torque TQex and the actual drive switching torque, the timing of switching from the driving state to the driven state is second attenuated as shown in FIG. It will be out of the period T2. In the example shown in FIG. 6A, the switching timing is the third decay period T3. As a result, there is a problem that a shock occurs when switching from the driven state to the driven state.

  Therefore, in the present embodiment, even if a deviation occurs between the estimated drive switching torque TQex and the actual drive switching torque, the timing of the changeover is within the second attenuation period T2, depending on the situation. The length L2 of the second decay period T2 is changed.

  Specifically, in the ROM of the EG-ECU 10, the length L2_normal of the second decay period T2 during normal time, the length L2_ac of the second decay period T2 when the air conditioning unit 13 is operating, the second decay period during cold The length L2_cold of T2 is stored. Here, the normal time refers to a time when the air conditioning unit 13 is in a non-operating state and the engine 2 is not cold (after completion of warm-up).

  The length L2_ac and the length L2_cold are longer than the length L2_normal. The length L2_ac and the length L2_cold may be the same length or different lengths. The EG-ECU 10 determines whether the length L2_normal, the length L2_ac, and the length L2_cold are stored in the ROM depending on whether the air conditioning unit 13 is not operating or the engine 2 is cold. Then, the largest length is selected (maximum value selection), and is set as the length L2 of the second attenuation period T2 (L2 = max [L2_normal, L2_ac, L2_cold]). However, when the air conditioning unit 13 is not in operation, the length L2_ac is set to “0”. Further, after the warm-up of the engine 2 is completed, the length L2_cold is set to “0”.

  Therefore, for example, during normal times, the air conditioning unit 13 is in a non-operating state and the engine 2 is in a non-cold state, so the length L2_ac and the length L2_cold are both “0”. Thereby, at the normal time, the longest length L2_normal is selected from these three lengths, and is set as the length L2 of the second attenuation period T2.

  If the air conditioning unit 13 is in the activated state, the length L2_ac longer than the length L2_normal is selected and set as the length L2 of the second decay period T2. Further, if the engine 2 is cold, a length L2_cold that is longer than the length L2_normal is selected and set as the length L2 of the second decay period T2.

  As described above, in the present embodiment, the EG-ECU 10 sets the second attenuation period T2 at the normal time on condition that the air conditioning unit 13 is in an operating state or when the engine 2 is cold. It is set longer than the second decay period T2. The EG-ECU 10 in the present embodiment constitutes a control means according to the present invention.

  Therefore, when the air conditioning unit 13 is operating or when the engine 2 is cold, the second decay period T2 is increased, that is, expanded as shown in FIG. Even when there is a deviation from the drive switching torque, the timing of switching from the drive state to the driven state falls within the second decay period T2. Thereby, the shock at the time of the switching is suppressed.

  At this time, the attenuation rate ΔTQ2 in the expanded second attenuation period T2 is the same as the normal attenuation rate ΔTQ2. That is, even if the second decay period T2 is extended, the slope of the output torque of the engine 2 that is attenuated does not change.

  Further, the attenuation width (torque width) of the output torque of the engine 2 in the second attenuation period T2 increases from the normal attenuation width (torque width) as the second attenuation period T2 increases. This is because the value of the length L2 is increased without changing the value of the attenuation rate ΔTQ2 in the above-described calculation formula “TQm = ΔTQ2 × L2 / 2” of the minute torque TQm.

  Next, the output torque attenuation operation by the EG-ECU 10 will be described with reference to FIG. The output torque attenuation operation shown in the flowchart shown in FIG. 7 starts at time t1 shown in FIG.

  First, the EG-ECU 10 determines the length L2_normal, the length stored in the ROM depending on whether it is normal time, the air conditioning unit 13 is in operation, or the engine 2 is cold. The length L2 of the second attenuation period T2 is set by selecting the maximum value from the length L2_ac and the length L2_cold (step S1). The EG-ECU 10 is in a normal state based on, for example, a signal indicating ON / OFF of an air conditioner (A / C) switch transmitted from the A / C-ECU 14 or a cooling water temperature acquired from the water temperature sensor 38. It can be determined whether the unit 13 is operating or when the engine 2 is cold.

  Next, the EG-ECU 10 estimates the current torque TQc (step S2), estimates the drive switching torque TQex, and uses the above-described calculation formula “TQm = ΔTQ2 × L2 / 2” to thereby calculate the first decay period T1. The target torque TQex + TQm at is calculated (step S3).

  Then, the EG-ECU 10 attenuates the output torque of the engine 2 to the start torque TQex + TQm over the length L1 in the first attenuation period T1 (step S4).

  Subsequently, the EG-ECU 10 attenuates the output torque of the engine 2 to the end torque TQex-TQm with the attenuation rate ΔTQ2 over the set length L2 in the second attenuation period T2 (step S5).

  Next, in the third damping period T3, the EG-ECU 10 attenuates the output torque of the engine 2 using the output torque TQfc of the engine 2 when the fuel supply to the engine 2 is stopped as a target torque over a length L3. (Step S6). When the third decay period T3 ends, the EG-ECU 10 controls the injector 44 so as not to inject fuel, and stops fuel supply to the engine 2 (step S7).

  As described above, in the control device for an internal combustion engine according to the present embodiment, the operating state of the engine 2 is changed from the driving state to the driven state on the condition that the air conditioning unit 13 is in the operating state or when the engine 2 is cold. The second decay period T2 including the period during which the air conditioning unit 13 is switched to is set longer than the second decay period T2 that is set when the air conditioning unit 13 is in the non-operating state and the non-cold state, that is, the second decay period T2 in the normal time. For this reason, the control device for an internal combustion engine according to the present embodiment switches the engine 2 from the driving state to the driven state even when the actual driving switching torque deviates from the estimated driving switching torque TQex. The replacement timing can be kept within the second attenuation period T2 that is set to be long. Therefore, it is possible to reliably suppress a shock to the vehicle 1 when the engine 2 is switched from the driving state to the driven state.

  In addition, the control device for an internal combustion engine according to the present embodiment is configured so that the engine 2 and the drive wheels 8L have the damping rate ΔTQ1 higher than the predetermined damping rate ΔTQ2 during the second damping period T2 before the second damping period T2. , 8R, a first damping period T1 is set for attenuating the output torque over a natural number times the natural vibration period Tu of the power transmission system. As a result, it is possible to suppress the so-called sneezing that occurs when the vehicle 1 vibrates in the front-rear direction, which is generated by significantly reducing the damping rate of the output torque of the engine 2 in the second damping period T2.

  Further, the control device for an internal combustion engine according to the present embodiment, after the end of the second damping period T2, the engine 2 and the drive wheels 8L, with the damping rate ΔTQ3 higher than the predetermined damping rate ΔTQ2 in the second damping period T2. A third damping period T3 is set in which the output torque is attenuated by taking a time that is a natural number times the natural vibration period Tu of the power transmission system interposed between the power transmission system and 8R. As a result, it is possible to suppress the sneezing that occurs when the fuel supply is stopped after the third decay period T3.

  Further, in the second damping period T2, the control device for an internal combustion engine according to the present embodiment attenuates the output torque at a predetermined damping rate ΔTQ2 from the start torque TQex + TQm to the end torque TQex−TQm. Therefore, the switching timing from the driving state of the engine 2 to the driven state can be controlled at the center of the second decay period T2. That is, in the second decay period T2, the periods before and after the switching timing can be set to the same length. Thereby, for example, even when the actual drive switching torque is shifted in any of the increase / decrease directions with respect to the estimated drive switching torque TQex, the switching timing can be kept within the second attenuation period T2. Therefore, even if a slight shift occurs in the actual drive switching torque, a shock to the vehicle 1 at the time of the switching can be reliably suppressed.

  Furthermore, in the control apparatus for an internal combustion engine according to the present embodiment, the drive switching torque TQex is estimated based on predetermined parameters including the load of the air conditioning unit 13 and the cooling water temperature of the engine 2. During cold weather, the error in estimating the drive switching torque TQex may become large. That is, the actual drive switching torque may deviate from the estimated drive switching torque TQex. The control device for an internal combustion engine according to the present embodiment sets the second attenuation period T2 to be long when the air conditioning unit 13 in which such an error may occur or when the engine 2 is cold, so that the actual drive switching torque is estimated. Even in the case of deviation from the drive switching torque TQex, the timing of switching from the driving state of the engine 2 to the driven state can be kept within the second attenuation period T2 that is set longer. Therefore, it is possible to reliably suppress a shock to the vehicle 1 when the engine 2 is switched from the driving state to the driven state.

  In the present embodiment, the EG-ECU 10 has been described as the one that attenuates the output torque of the engine 2 by changing the ignition timing for the engine 2, but in the present invention, the EG-ECU 10 The output torque of the engine 2 may be attenuated by varying at least one of the intake air amount and the ignition timing. Thereby, the attenuation rate ΔTQ of the output torque of the engine 2 can be adjusted.

  In the present embodiment, an example in which the control device for an internal combustion engine according to the present invention is applied to a vehicle having an automatic transmission has been described. However, the control device for an internal combustion engine according to the present invention includes a continuously variable transmission. It may be applied to other vehicles.

  In the present embodiment, the example in which the control device for an internal combustion engine according to the present invention is applied to an FR vehicle has been described. However, the control device for an internal combustion engine according to the present invention is applied to an FF (Front engine Front drive) vehicle. Alternatively, it may be applied to a four-wheel drive vehicle.

  Moreover, in this Embodiment, although the example which applied the gasoline engine which uses gasoline as a fuel as an internal combustion engine which concerns on this invention was demonstrated, you may apply a diesel engine as an internal combustion engine which concerns on this invention.

  When a diesel engine is applied as the internal combustion engine according to the present invention, the EG-ECU 10 is configured to attenuate the output torque of the engine 2 by changing the fuel injection amount to the engine 2.

  Further, in the present embodiment, the EG-ECU 10 is based on a map in which the output torque of the engine 2 is associated with the engine speed of the engine 2, the intake air amount, and the ignition timing for the spark plug 45. In the above description, the output torque of the engine 2 is estimated.

  In contrast, the EG-ECU 10 according to the present invention recirculates a part of the exhaust gas in the exhaust pipe 35 into the intake pipe 30 in addition to the engine speed of the engine 2, the intake air amount, and the ignition timing. Based on a map in which the output torque of the engine 2 is associated with at least one of the EGR rate in the EGR (Exhaust Gas Recirculation) device, the cooling water temperature obtained from the water temperature sensor 38, and the phase angle in the VVT control, The output torque of the engine 2 may be estimated.

  As described above, the control device for an internal combustion engine according to the present invention can surely suppress a shock to the vehicle when the internal combustion engine is switched from the driving state to the driven state, and the internal combustion engine is satisfied when a predetermined condition is satisfied. The present invention is useful for a control device for an internal combustion engine that executes a fuel cut for stopping the supply of fuel to the engine.

1 vehicle 2 engine (internal combustion engine)
9 Automatic transmission 10 EG-ECU (control means)
13 Air conditioning unit (air conditioner)
14 A / C-ECU
38 Water temperature sensor 107 Pressure sensor 108 Refrigerant temperature sensor T1 First decay period (drive torque decay period)
T2 Second decay period (operating state switching period)
T3 Third decay period (driven torque decay period)
TQex Drive switching torque ΔTQ1, ΔTQ2, ΔTQ3 Decay rate TQex + TQm Start torque TQex-TQm End torque

Claims (5)

In a control device for an internal combustion engine that executes a fuel cut that stops fuel supply to the internal combustion engine after the output torque of the internal combustion engine is attenuated when a predetermined predetermined fuel cut execution condition is satisfied,
When the output torque is attenuated, an operating state switching period including a period during which the operating state of the internal combustion engine switches from a driving state that generates driving force to a driven state that receives driving force is set, and during the operating state switching period , Comprising a control means for attenuating the output torque at a predetermined predetermined attenuation rate,
The control means sets the operation state switching period as a non-operating state of the air conditioner on condition that an air conditioner driven by the output of the internal combustion engine is in an operating state or when the internal combustion engine is cold. And a control device for an internal combustion engine, which is set longer than an operation state switching period set when the internal combustion engine is not cold.   The control means is a natural number multiple of the natural vibration period of the power transmission system interposed between the internal combustion engine and the drive wheels at a damping rate higher than the predetermined damping rate before the start of the operating state switching period. A driving torque decay period for damping the output torque over time is set, and after the operation state switching period, the natural vibration period of the power transmission system with a damping rate higher than the predetermined damping rate is set. 2. The control device for an internal combustion engine according to claim 1, wherein a drive-time torque decay period in which the output torque is attenuated over several times is set.   The control means estimates a drive switching torque when the operating state of the internal combustion engine switches from a driving state to a driven state, and is higher than the driving switching torque by a minute torque during the driving state switching period. 3. The control of the internal combustion engine according to claim 1, wherein the output torque is attenuated at the predetermined attenuation rate from a start torque to an end torque that is lower than the drive switching torque by the minute torque. apparatus.   The internal combustion engine according to any one of claims 1 to 3, wherein the drive switching torque is estimated based on predetermined parameters including a load of the air conditioner and a coolant temperature of the internal combustion engine. Engine control device.   The said control means attenuates the said output torque by fluctuating at least one of the intake air amount with respect to the said internal combustion engine, and ignition timing, The claim of any one of Claim 1 thru | or 4 characterized by the above-mentioned. Control device for internal combustion engine.

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