JP5783100B2 - Control device for internal combustion engine - Google Patents

Description

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

  Conventionally, in a vehicle equipped with an internal combustion engine as an internal combustion engine, for the purpose of improving fuel efficiency, when the output torque of the internal combustion engine is not required, such as during deceleration, a fuel cut that stops the supply of fuel to the internal combustion engine The thing provided with the control apparatus which performs is known.

  In such a vehicle, when a fuel cut is executed, the difference between the output torque output from the internal combustion engine before the fuel cut is executed and the output torque output from the internal combustion engine after the fuel cut is executed is A shock will occur.

  As a control device for an internal combustion engine for suppressing such a vehicle shock, a fuel cut means for cutting fuel supply to the internal combustion engine when a predetermined deceleration operation condition is satisfied, and a start of fuel cut by the fuel cut means are delayed by a predetermined time There has been known a fuel cut delay means for causing ignition timing retarding means for retarding the ignition timing during the fuel cut delay time (see, for example, Patent Document 1).

  With this configuration, the conventional control device for an internal combustion engine disclosed in Patent Document 1 attenuates the output torque of the internal combustion engine by retarding the ignition timing before executing the fuel cut, thereby reducing the fuel cut. The difference between the output torque output from the internal combustion engine before execution and the output torque output from the internal combustion engine after execution of fuel cut is reduced, and the occurrence of shock in the vehicle is suppressed.

Japanese Patent Laid-Open No. 10-030477

  However, the conventional control apparatus for an internal combustion engine as described in Patent Document 1 does not take into consideration the time for attenuating the output torque of the internal combustion engine and the attenuation rate when the output torque of the internal combustion engine is attenuated.

  More specifically, when the output torque of the internal combustion engine is attenuated and fuel is no longer supplied to the internal combustion engine, the torsional torque of the power transmission system interposed between the internal combustion engine and the drive wheels is released. As a result, torsional vibration may occur in the power transmission system.

  This torsional vibration may cause so-called squealing in which the vehicle vibrates in the front-rear direction, which may reduce drivability. This scuffing can be suppressed by attenuating the output torque of the internal combustion engine over a natural number times the natural period of the power transmission system and then releasing the torsional torque of the power transmission system.

  However, if the damping rate of the output torque of the internal combustion engine is made too high, the damping rate of the output torque of the internal combustion engine changes abruptly when fuel is no longer supplied to the internal combustion engine depending on the running state of the vehicle. As a result, the vehicle may be shocked and drivability may be reduced.

  Further, by attenuating the output torque of the internal combustion engine, the operating state of the internal combustion engine is switched from a driving state that generates a driving force to a driven state that receives the driving force. When the operating state of the internal combustion engine is switched from the driving state to the driven state, the torsional torque of the power transmission system is released and reverse torque is applied to the power transmission system, causing a shock to the vehicle and reducing drivability. I had to do it.

  Some conventional vehicles have a torque converter having a lockup clutch provided with a lockup damper. The lockup clutch is in any state between an engagement state in which the output shaft of the internal combustion engine and the input shaft of the transmission mechanism are directly connected and a release state in which the output shaft of the internal combustion engine and the input shaft of the transmission mechanism are released. Is supposed to take.

  For this reason, even if the output torque of the internal combustion engine is controlled in order to reduce the shock generated in the vehicle as described above, the influence of the torsion of the lockup damper when the lockup clutch is engaged is taken into consideration. Therefore, the shock when the operating state of the internal combustion engine is switched from the driving state to the driven state is not sufficiently suppressed, and drivability may be deteriorated.

  As described above, the conventional control device for an internal combustion engine has a problem that drivability may be lowered by stopping the fuel supply to the internal combustion engine after the output torque of the internal combustion engine is attenuated.

  The present invention has been made to solve such a problem, and is an internal combustion engine capable of suppressing a decrease in drivability due to stopping the fuel supply of the internal combustion engine after the output torque of the internal combustion engine is attenuated. An object of the present invention is to provide a control device.

  In order to achieve the above object, the control device for an internal combustion engine of the present invention includes (1) an engagement state in which the output shaft of the internal combustion engine and the input shaft of the transmission mechanism are directly connected, and the output shaft of the internal combustion engine and the transmission mechanism. A lockup clutch that takes one of the states between a release state in which the input shaft is released and an output torque output from the internal combustion engine when the lockup clutch is in the release state An internal combustion engine control device that is mounted on a vehicle including a torque converter that outputs to the transmission mechanism and that attenuates output torque of the internal combustion engine and then stops fuel supply to the internal combustion engine. A first damping period in which the torque is attenuated from the initial torque, and a period in which the operating state of the internal combustion engine is switched from a driving state that generates driving force to a driven state that receives driving force. Output torque attenuating means for attenuating the output torque of the internal combustion engine by dividing the output torque of the internal combustion engine into a third attenuation period for attenuating the output torque of the internal combustion engine to a torque for stopping fuel supply to the internal combustion engine; And a damping state changing means for changing the length of the first damping period and the third damping period and the damping rate of the output torque of the internal combustion engine in the second damping period according to the state of the lockup clutch. It has a configuration.

  With this configuration, the control apparatus for an internal combustion engine according to the present invention changes the lengths of the first damping period and the third damping period and the damping rate of the output torque of the internal combustion engine in the second damping period according to the state of the lockup clutch. Therefore, the output torque of the internal combustion engine can be attenuated without being affected by the state of the lockup clutch. Therefore, the control apparatus for an internal combustion engine according to the present invention can suppress a decrease in drivability due to stopping the fuel supply of the internal combustion engine after the output torque of the internal combustion engine is attenuated.

Further, in the control device for an internal combustion engine according to (1), (2) the damping state changing means includes the first damping period and the third damping period when the lockup clutch is in the engaged state. And the damping rate of the output torque of the internal combustion engine in the second damping period when the lockup clutch is in the engaged state than when in the released state. You may make it low.

  With this configuration, the control apparatus for an internal combustion engine according to the present invention takes a longer time in each of the first damping period and the third damping period when the lockup clutch is in the engaged state than when it is in the released state. In the second damping period, when the lockup clutch is in the engaged state, the output torque of the internal combustion engine is attenuated at a lower damping rate than in the released state. It is possible to reduce the influence of twist of the lockup damper when the clutch is engaged.

In the control device for an internal combustion engine according to the above (1) or (2), (3) an automatic transmission mode for changing a shift speed formed in the transmission mechanism in accordance with an operating state of the vehicle, and a shift operation. And a transmission mechanism control means for controlling the transmission mechanism in at least two modes: a manual transmission mode for changing a gear position formed in the transmission mechanism in response to the transmission mechanism. The lengths of the first decay period and the third decay period when controlled in the manual shift mode are made shorter than when the shift mechanism is controlled in the automatic shift mode, and the shift mechanism moves the manual shift mode. higher than when the internal combustion engine the speed change mechanism attenuation rate of the output torque of being controlled by said automatic shift mode in the second decay time when it is controlled by the mode It may be.

  With this configuration, the control device for an internal combustion engine according to the present invention allows the driver to allow a slight shock generated in the vehicle in the manual shift mode in which the shift speed formed in the transmission mechanism is changed according to the shift operation by the driver. Can give a quick feeling of deceleration.

  In the control device for an internal combustion engine according to any one of (1) to (3), (4) the output torque attenuation means varies at least one of an ignition timing and an intake air amount for the internal combustion engine. Thus, the output torque of the internal combustion engine may be attenuated.

  With this configuration, the control device for an internal combustion engine of the present invention can adjust the lengths of the first and third attenuation periods and the attenuation rate of the output torque of the internal combustion engine in the second attenuation period.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the internal combustion engine which can suppress the fall of drivability by stopping the fuel supply of an internal combustion engine after attenuating the output torque of an internal combustion engine can be provided.

1 is a functional block diagram showing a configuration of a vehicle equipped with a control device for an internal combustion engine according to an embodiment of the present invention. It is a schematic sectional drawing of the engine shown in FIG. It is a schematic perspective view of the engine shown in FIG. FIG. 2 is a schematic diagram of the automatic transmission shown in FIG. 1. It is the schematic for demonstrating the shift position which the shift lever shown in FIG. 4 takes. It is a graph for demonstrating the fuel cut by the electronic control unit for engines shown in FIG. It is the schematic for demonstrating the time control map which the control apparatus of the internal combustion engine which concerns on embodiment of this invention refers. It is the schematic for demonstrating the attenuation factor control map which the control apparatus of the internal combustion engine which concerns on embodiment of this invention refers. It is a flowchart which shows the output torque attenuation | damping operation | movement by the engine electronic control unit which comprises the control apparatus of the internal combustion engine which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below 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. And an automatic transmission electronic control unit (hereinafter referred to as “TM-ECU”) 12 that automatically controls.

  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 a 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 via the high-speed CAN, and exchanges various control signals and data with the other ECUs such as the TM-ECU 12. .

  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, 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 via the high-speed CAN, and exchanges various control signals and data with the other ECUs such as the EG-ECU 10. .

  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.

  As shown in FIG. 5, the shift lever 93 in the present embodiment does not transmit driving force to the P (parking) position selected during parking, the R (reverse) position selected during reverse traveling, and the drive wheels 8L and 8R. An N (neutral) position that is sometimes selected, a D (drive) position that is selected during forward movement, and an S (sequential) position that is selected during manual shifting are taken.

  When the shift lever 93 is in the D position, the TM-ECU 12 takes the automatic transmission mode as the control mode of the transmission mechanism 5 and responds to the driving state of the vehicle 1 such as the vehicle speed and the accelerator opening obtained from the EG-ECU 10. The hydraulic control circuit 11 is controlled so as to cause the transmission mechanism 5 to form the selected gear stage.

  Further, when the shift lever 93 is in the S position, the TM-ECU 12 takes the manual transmission mode as the control mode of the transmission mechanism 5 and when the shift lever 93 is moved to + by the shift operation, the transmission mechanism The hydraulic control circuit 11 is controlled to increase the shift speed to be formed at 5 by one speed, and when the shift lever 93 is moved to-, the shift speed to be formed at the transmission mechanism 5 is decreased by one speed. The hydraulic control circuit 11 is controlled. Thus, the TM-ECU 12 constitutes a speed change mechanism control means in the present invention.

  Further, the TM-ECU 12 indicates that the lock-up clutch 76 is engaged and disengaged according to the vehicle speed obtained from the EG-ECU 10, the accelerator opening, the coolant temperature, the gear stage formed in the transmission mechanism 5, and the like. The hydraulic control circuit 11 is controlled so as to take either state between the two.

  Hereinafter, the fuel cut executed by the EG-ECU 10 in 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. 6, the EG-ECU 10 detects in advance that the accelerator pedal position 90 is 0, that is, the accelerator is turned off, by the accelerator position sensor 91 at time t0. 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.

  The EG-ECU 10 includes a first attenuation period T1 in which the output torque of the engine 2 is attenuated from the initial torque, and a first period in which the operating state of the engine 2 is switched from a driving state that generates driving force to a driven state that receives driving force. The output torque of the engine 2 is attenuated by being divided into two attenuation periods T2 and a third attenuation period T3 in which the output torque of the engine 2 is attenuated to a torque when fuel supply to the engine 2 is stopped. Thus, EG-ECU10 comprises the output torque attenuation means in this invention.

  As shown in FIG. 7, the ROM of the EG-ECU 10 stores the length of the first damping period T1 and the length of the third damping period T3 with respect to the control mode of the speed change mechanism 5 and the state of the lockup clutch 76. Is stored for each gear position formed in the transmission mechanism 5. In the ROM of the EG-ECU 10, the length of the second decay period T2 is stored as a constant value L2 for each shift stage formed in the transmission mechanism 5.

  In this time control map, the first damping period T1 when the control mode of the transmission mechanism 5 is the automatic transmission mode and the lockup clutch (described as “L / U” in the figure) 76 is in the engaged state. Lc1, the control mode of the transmission mechanism 5 is the automatic transmission mode, the length Lf1 of the first damping period T1 when the lockup clutch 76 is in the released state, and the control mode of the transmission mechanism 5 is The relationship with the length Lm1 of the first decay period T1 in the manual shift mode satisfies Lc1> Lf1> Lm1.

  Here, the lengths Lc1, Lf1, and Lm1 are respectively set to natural number times the natural vibration period of the power transmission system interposed between the engine 2 and the drive wheels 8L, 8R. Further, the natural vibration period of the power transmission system is determined in advance by experiment for each gear stage formed in the transmission mechanism 5.

  The control mode of the transmission mechanism 5 is the automatic transmission mode, the length Lc3 of the third damping period T3 when the lockup clutch 76 is in the engaged state, and the control mode of the transmission mechanism 5 is the automatic transmission mode. The length Lf3 of the third damping period T3 when the lockup clutch 76 is in the released state, and the length Lm3 of the third damping period T3 when the control mode of the transmission mechanism 5 is the manual transmission mode. The relationship between and satisfies Lc3> Lf3> Lm3. Here, the lengths Lc3, Lf3, and Lm3 are respectively set to natural number times the natural vibration period of the power transmission system.

  Further, in the ROM of the EG-ECU 10, as shown in FIG. 8, the damping rate of the output torque of the engine 2 in the second damping period T2 with respect to the control mode of the transmission mechanism 5 and the state of the lockup clutch 76. Is stored for each gear position formed in the transmission mechanism 5.

  In this damping rate control map, the output mode damping rate ΔTQc2 of the engine 2 and the control of the transmission mechanism 5 when the control mode of the transmission mechanism 5 is the automatic transmission mode and the lockup clutch 76 is in the engaged state. Decay rate ΔTQf2 of the output torque of the engine 2 when the mode is the automatic transmission mode and the lockup clutch 76 is in the released state, and the output of the engine 2 when the control mode of the transmission mechanism 5 is the manual transmission mode The relationship between the torque attenuation rate ΔTQm2 and the second attenuation period T2 satisfies ΔTQc2 <ΔTQf2 <ΔTQm2.

  In FIG. 6, the EG-ECU 10 estimates the output torque of the engine 2 at time t1. The ROM of the EG-ECU 10 stores a map in which the output torque of the engine 2 is previously associated with the engine speed, the intake air amount, and the ignition timing of the engine 2 through experiments.

  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. The output torque of the engine 2 is estimated by specifying the attached output torque of the engine 2.

  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 ROM of the EG-ECU 10 stores the vehicle speed, the gear stage formed in the transmission mechanism 5, auxiliary loads such as an air conditioner, alternator and oil pump, and the coolant 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 is estimated by specifying the drive switching torque TQex associated with the map with respect to the water temperature obtained from 38.

  The EG-ECU 10 determines the engine in the second damping period T2 associated with the damping rate control map shown in FIG. 8 with respect to the control mode of the speed change mechanism 5 obtained from the TM-ECU 12 and the state of the lockup clutch 76. 2 based on the attenuation rate ΔTQc2, ΔTQf2 or ΔTQm2 (hereinafter collectively referred to as “attenuation rate ΔTQ2”) of the output torque 2 and the length L2 of the second attenuation period T2. A difference TQm between the output torque of the engine 2 and the drive switching torque TQex is calculated by the following mathematical formula.

  TQm = ΔTQ2 × L2 / 2

  From time t1, the EG-ECU 10 determines the length Lc1 of the first decay period T1 associated with the time control map shown in FIG. 7 for the control mode of the transmission mechanism 5 and the state of the lockup clutch 76. Over time of Lf1 or Lm1 (hereinafter collectively referred to as “L1”), the output torque of the engine 2 is attenuated using the torque TQex + TQm as a target torque.

  In the present embodiment, as shown in FIG. 6, the EG-ECU 10 attenuates the output torque of the engine 2 by changing the ignition timing for the engine 2.

  The EG-ECU 10 performs the damping rate control shown in FIG. 8 with respect to the control mode of the transmission mechanism 5 and the state of the lockup clutch 76 when the time of the length L1 elapses from the time t1 and the time t2 is reached. The output torque of the engine 2 is attenuated over the length L2 of the second attenuation period T2 at the attenuation rate ΔTQ2 of the engine 2 in the second attenuation period T2 associated with the map. .

  Further, the time control map shown in FIG. 7 is shown for the control mode of the transmission mechanism 5 and the state of the lockup clutch 76 at time t3 when the time of the length L2 has elapsed from time t2. The torque TQfc of the engine 2 when the fuel supply to the engine 2 is stopped over the time of the length Lc3, Lf3 or Lm3 (hereinafter collectively referred to as “L3”) of the third decay period T3 associated with Is used to attenuate the output torque of the engine 2. Further, the EG-ECU 10 controls the injector 44 so that the fuel is not injected when the time of the length L3 has elapsed from the time t3 and the time t4 is reached.

  As described above, the EG-ECU 10 determines the time shown in FIG. 7 with respect to the control mode of the transmission mechanism 5 and the state of the lockup clutch 76 in the first damping period T1 from time t1 to time t2. In the second damping period T2 from the time t2 to the time t3, the lockup clutch is applied in the second damping period T2 from the time t2 to the time t3 by attenuating the output torque of the engine 2 over the length L1 of the first damping period T1 associated with the control map. Without being influenced by the state of 76, the engine 2 is configured to suppress the squealing and shock that occur when the damping rate of the output torque of the engine 2 is greatly reduced.

  Further, the EG-ECU 10 corresponds to the damping rate control map shown in FIG. 8 for the control mode of the transmission mechanism 5 and the state of the lockup clutch 76 in the second damping period T2 from time t2 to time t3. By attenuating the output torque of the engine 2 by the attached damping rate ΔTQ2, the power transmission system can be used when the operating state of the engine 2 is switched from the driving state to the driven state without being affected by the state of the lockup clutch 76. It is comprised so that the shock which generate | occur | produces in may be prevented.

  Further, the EG-ECU 10 associates the control mode of the transmission mechanism 5 and the state of the lockup clutch 76 with the time control map shown in FIG. 7 in the third damping period T3 from time t3 to time t4. The fuel is injected by the injector 44 at time t4 without being affected by the state of the lockup clutch 76 by attenuating the output torque of the engine 2 over the length L3 of the third damping period T3. It is comprised so that the sneezing and the shock which generate | occur | produce by stopping may be suppressed. As described above, the EG-ECU 10 constitutes a damping state changing unit in the present invention.

  The output torque attenuation operation by the EG-ECU 10 configured as described above will be described with reference to the flowchart shown in FIG. The output torque attenuation operation shown in the flowchart shown in FIG. 9 starts at time t1 shown in FIG.

  First, the EG-ECU 10 specifies the lengths L1 and L3 of the first attenuation period T1 and the third attenuation period T3 based on the time control map (step S1), and based on the attenuation rate control map, the second The attenuation rate ΔTQ2 in the attenuation period T2 is specified (step S2).

  Specifically, the EG-ECU 10 determines the length L1 of the first decay period T1 and the third decay period associated with the time control map for the control mode of the transmission mechanism 5 and the state of the lockup clutch 76. The length L3 of T3 and the attenuation rate ΔTQ2 associated with the attenuation rate control map are specified.

  Further, the EG-ECU 10 estimates the current torque TQc (step S3), and calculates the target torque TQex + TQm in the first decay period T1 by estimating the drive switching torque TQex (step S4).

  In the first attenuation period T1, the EG-ECU 10 attenuates the output torque of the engine 2 to the target torque TQex + TQm over a length L1 (step S5). In the second attenuation period T2, the EG-ECU 10 attenuates the output torque of the engine 2 with the attenuation rate ΔTQ2 over a length L2 (step S6).

  In the third decay 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 S7). 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 S8).

  As described above, the control apparatus for an internal combustion engine according to the embodiment of the present invention provides the output torque of the engine 2 in the lengths L1 and L3 of the first damping period T1 and the third damping period T3 and the second damping period T2. Since the damping rate ΔTQ2 is changed according to the state of the lockup clutch 76, the output torque of the engine 2 can be attenuated without being affected by the state of the lockup clutch 76.

  Therefore, the control apparatus for an internal combustion engine according to the embodiment of the present invention can suppress a decrease in drivability due to stopping the fuel supply of the engine 2 after the output torque of the engine 2 is attenuated.

  In addition, the control apparatus for an internal combustion engine according to the embodiment of the present invention optimally sets the maps shown in FIGS. 7 and 8 by experiment so that the vehicle 1 does not sneeze or shock, It is possible to shorten the time required for stopping the fuel injection by the injector 44 after the output torque of the engine 2 is attenuated as compared with the conventional one.

  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.

  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 an EGR rate in an EGR (Exhaust Gas Recirculation) device, a water temperature obtained from the water temperature sensor 38, and a phase angle in VVT control. The output torque of 2 may be estimated.

  Further, in the present embodiment, the lockup clutch 76 has been described as being in any state between the engaged state and the released state, but specifically, the pump impeller 71 and the turbine impeller 73. And a flex lock-up state in which the vehicle is slid at an arbitrary sliding rate.

  Here, when the lockup clutch 76 is in the flex lockup state, the EG-ECU 10 controls the output torque of the engine 2 assuming that the lockup clutch 76 is in the released state.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the control apparatus for an internal combustion engine according to the present invention has an effect that it is possible to suppress a decrease in drivability due to stopping the fuel supply of the internal combustion engine after the output torque of the internal combustion engine is attenuated. The present invention is useful for a control device for an internal combustion engine that stops the fuel supply to the internal combustion engine after the output torque of the internal combustion engine is attenuated.

1 vehicle 2 engine (internal combustion engine)
3 Torque converter 5 Transmission mechanism 8L, 8R Drive wheel 10 EG-ECU (output torque attenuation means, attenuation state change means)
12 TM-ECU (transmission mechanism control means)
76 Lock-up clutch

Claims (4)

A lock that takes one of an engagement state in which the output shaft of the internal combustion engine and the input shaft of the transmission mechanism are directly connected and a release state in which the output shaft of the internal combustion engine and the input shaft of the transmission mechanism are released. The internal combustion engine is mounted on a vehicle including a torque converter that has an up clutch and amplifies an output torque output from the internal combustion engine and outputs the output torque to the transmission mechanism when the lock-up clutch is in the released state. In the control device for an internal combustion engine that stops the fuel supply to the internal combustion engine after the output torque of the engine is attenuated,
A first attenuation period in which the output torque of the internal combustion engine is attenuated from an initial torque; and a second attenuation period including a period in which the operating state of the internal combustion engine is switched from a driving state that generates driving force to a driven state that receives driving force; Output torque attenuating means for attenuating the output torque of the internal combustion engine by dividing it into a third attenuation period for attenuating the output torque of the internal combustion engine to a torque for stopping fuel supply to the internal combustion engine;
And a damping state changing means for changing the length of the first damping period and the third damping period and the damping rate of the output torque of the internal combustion engine in the second damping period according to the state of the lockup clutch. A control device for an internal combustion engine. The damping state changing means makes the lengths of the first damping period and the third damping period when the lock-up clutch is in the engaged state longer than when the lock-up clutch is in the released state, 2. The control device for an internal combustion engine according to claim 1, wherein an attenuation rate of an output torque of the internal combustion engine in the second damping period when in the engaged state is made lower than that in the released state. At least two of an automatic shift mode for changing a shift speed formed in the speed change mechanism according to the driving state of the vehicle and a manual shift mode for changing a shift speed formed in the speed change mechanism according to a shift operation. Transmission mechanism control means for controlling the transmission mechanism in a mode;
The damping state changing means controls the length of the first damping period and the third damping period when the transmission mechanism is controlled in the manual transmission mode, and the transmission mechanism is controlled in the automatic transmission mode. When the transmission mechanism is controlled in the automatic transmission mode, the damping rate of the output torque of the internal combustion engine in the second attenuation period when the transmission mechanism is controlled in the manual transmission mode . 3. The control device for an internal combustion engine according to claim 1, wherein the control device is higher.   The output torque attenuating means attenuates the output torque of the internal combustion engine by changing at least one of an ignition timing for the internal combustion engine and an intake air amount. A control device for an internal combustion engine according to claim 1.

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