JP2018135869A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce fuel consumption and a required torque.SOLUTION: A control device of an engine 10 receives a demand for reducing an output torque of the engine 10, and stops cylinders with the number approximate to a torque reduction demand value 406. The control device of the engine 10 has a throttle valve 70, an electric control throttle motor 72, and an electric control throttle control part 318. The throttle valve 70 and the electric control throttle motor 72 adjust an amount of air sucked by the engine 10. The electric control throttle control part 318 controls the throttle valve 70 and the electric control throttle motor 72 so that an amount of air sucked by the engine 10 becomes the amount of suction air according to a cylinder stopping number.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a control device that controls engine torque, and particularly to an engine control device that stops combustion by stopping the operation of an intake valve and an exhaust valve for each cylinder and approximates an engine output torque reduction request value. The present invention relates to an engine control apparatus that deactivates the number of cylinders to be operated.

  In vehicles including automobiles, for example, output signals of various sensors such as an accelerator opening sensor that detects an operation amount of an accelerator pedal and a throttle opening sensor that detects a throttle opening are input to an engine control device. The engine control device executes various engine control programs by a built-in microcomputer, and controls each actuator that operates, for example, a throttle valve, a fuel injection valve, and a spark plug according to the engine operating state. Control.

  The output torque of the engine is controlled by adjusting the opening of a throttle valve driven by an electric throttle motor according to the accelerator opening and the engine operating state, thereby increasing or decreasing the amount of air taken in by the engine. .

  In addition, other control units installed in the vehicle, such as an AT C / U (control unit) that controls the transmission shift, reduce the engine output torque during the shift to reduce shock during the shift. There is a need. Accordingly, the AT C / U requests the engine control device to temporarily reduce the output torque by using the communication function between the control units.

  In the engine control device that has received a torque reduction request, a rapid torque reduction is realized by fuel cut and ignition timing retard.

  In the torque reduction by the fuel cut, the torque reduction amount is changed by adjusting the number of cylinders from which the fuel is cut. When the fuel in the partial cylinder is cut, the air that has passed through the fuel cut cylinder and the combustion gas discharged from the non-fuel cut cylinder are mixed in the exhaust passage of the engine. Therefore, when unburned fuel is contained in the combustion gas, the unburned fuel reacts with air in the exhaust passage and burns. As a result, there is a problem that when the high-temperature gas reaches the catalyst disposed in the exhaust passage, thermal degradation of the catalyst proceeds.

  In the engine output control device disclosed in Patent Document 1, an operation region in which unburned fuel is included in combustion gas is determined, and the number of cylinders for cutting fuel is limited according to a torque reduction request.

Japanese Patent No. 2550773

  According to the engine output limiting device disclosed in Patent Document 1, when the number of fuel cut cylinders is increased in order to reduce engine output, unburned fuel and air that has passed through the fuel cut cylinders are used as catalysts. Reaching and burning can cause the catalyst to thermally degrade. Therefore, the engine output control device of Patent Document 1 corrects the number of fuel-cut cylinders in a direction in which heat generation of the catalyst can be prevented.

  However, when the number of fuel cut cylinders is corrected and reduced, in order to achieve the required torque reduction amount, for example, it is necessary to increase the retard amount by which the ignition timing is delayed to ensure the torque reduction amount. Since the ignition timing retards away from the ignition timing with the highest fuel consumption rate, there is a problem that the fuel consumption rate deteriorates.

  An object of the present invention is to provide an engine control device that reduces fuel consumption and required torque.

  The engine control apparatus according to the present invention receives a request to reduce the output torque of the engine, and pauses the cylinders corresponding to the number of cylinders that approximate the torque reduction request value. The engine control device includes an intake air amount adjustment unit and a control unit. The intake air amount adjustment unit adjusts the amount of air taken in by the engine. The control unit performs control so that the amount of air taken into the engine becomes the amount of intake air corresponding to the cylinder deactivation number.

  According to the present invention, the engine output torque reduction request can be received, and the cylinders corresponding to the number of cylinders approximating the torque reduction request value can be stopped, and thermal deterioration of the catalyst can be prevented while the torque is being reduced. Meanwhile, fuel consumption and torque can be reduced.

An example of the block diagram of the engine system by which an engine control apparatus is mounted is shown. An example of the block diagram of the internal structure of the control apparatus of an engine is shown. An example of the control block diagram of the control apparatus of an engine is shown. An example of the block diagram of the control block of a torque reduction request value calculation part is shown. The timing which selects a dormant cylinder is shown. The flow of the torque reduction request | requirement control processing by the engine control apparatus is shown. An overall flow of the engine control device is shown. The flow which calculates | requires a torque reduction request value and the output of each control part is shown. The flow which calculates | requires a torque reduction request value and the output of each control part is shown. The map which calculates driver demand torque is shown. The table which searches the number of idle cylinders is shown. The table which searches the amount of ignition reductions is shown. The table which searches a target number of rotations is shown. The flow of an electric control throttle control part is shown. The flow of a fuel injection control part is shown. The flow of a cylinder deactivation control part is shown. The flow of an ignition control part is shown.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings.

  FIG. 1 schematically shows an overall configuration of an internal combustion engine on which an engine control device is mounted.

  An engine 10 as an internal combustion engine shown in FIG. 1 is, for example, a spark ignition type multi-cylinder engine having four cylinders. The engine 10 includes a cylinder 11 including a cylinder head 11a and a cylinder block 11b, and a piston 15 that is slidably inserted into each cylinder of the cylinder 11. The piston 15 is connected to the crankshaft via the connecting rod 14.

  The ring plate 46 that rotates in synchronization with the crankshaft is provided with a protrusion at every predetermined angle. The crank angle sensor 47 measures the passage time between the aforementioned protrusions and calculates the rotation speed of the engine 10.

  Above each piston 15, a combustion chamber 17 having a ceiling with a predetermined shape is defined, and an ignition plug 39 to which a high ignition signal is supplied from the ignition coil 34 faces each combustion chamber 17. It is provided as follows.

  The combustion chamber 17 communicates with the intake passage 20. The intake passage 20 includes an air cleaner 19, a compressor 41, a throttle valve 70 as a part of the “intake air amount adjustment mechanism”, an intercooler 18, a collector 27, an intake manifold 28, and an intake port 29. ing. Air necessary for fuel combustion passes through the intake passage 20 and passes through an intake valve 21 that is opened and closed by an intake camshaft 23 disposed at an end of an intake port 29 that is a downstream end of the intake passage 20. Then, it is sucked into each combustion chamber 17. A cam angle sensor 25 is disposed on the intake camshaft 23.

  A fuel injection valve 30 for injecting fuel toward the intake port 29 is provided in the intake manifold 28 of the intake passage 20 so as to face each cylinder.

  The throttle valve 70 is a part of the “intake air amount adjusting mechanism” so that the throttle opening becomes an appropriate throttle opening according to the signal of the accelerator opening sensor 71 that detects the accelerator opening of the driver and the driving state. The electric throttle motor 72 is driven. The opening degree of the throttle valve 70 is transmitted to the ECU (control unit) 100 by the throttle opening degree sensor 73.

  An intake pipe pressure sensor 48 that detects the pressure in the intake passage 20 is disposed in the collector 27. A water temperature sensor 49 that detects the cooling water temperature of the engine 10 is disposed in the cylinder block of the engine 10.

  An air flow sensor (thermal air flow meter) 50 that detects the flow rate of intake air is disposed upstream of the compressor 41 in the intake passage 20. The air flow sensor 50 has a bridge circuit. As the intake air amount (mass flow rate) increases, the bridge circuit increases the current value flowing through the hot wire (heating resistor) arranged in the intake air flow to be measured, and as the intake air amount decreases. Reduce the value of the current flowing through the hot wire. The heating resistance current value flowing through the hot wire of the air flow sensor 50 is extracted as a voltage signal and transmitted to the ECU (engine control unit) 100.

  An air-fuel mixture of the air sucked through the intake passage 20 and the fuel injected from the fuel injection valve 30 is sucked into the combustion chamber 17 through the intake valve 21 and is connected to the ignition coil 34. It is burned by spark ignition. Exhaust gas after combustion in the combustion chamber 17 is exhausted from the combustion chamber 17 through an exhaust valve 22 that is opened and closed by an exhaust camshaft 24, and includes an exhaust port, an exhaust manifold, and an exhaust pipe (not shown). It passes through the exhaust passage 40 and is discharged into the outside atmosphere.

  Here, a turbine 42 is disposed in the exhaust passage 40. The turbine 42 is connected to a compressor 41 disposed in the intake passage 20 via a common shaft 45. When the pressure of the exhaust gas discharged from the combustion chamber 17 exceeds a predetermined value, the engine 10 starts supercharging by the compressor 41 and supplies compressed intake air to the inside of the combustion chamber 17. Here, the compressed hot air is cooled by the intercooler 18. Note that when the supercharging pressure becomes equal to or higher than a predetermined value, the ECU 100 is configured so that the recirculation valve 43 disposed in the intake passage 20 and the waste gate valve 44 disposed in the exhaust passage 40 are not supercharged. And control to open the valve.

  Further, on the downstream side of the turbine 42 in the exhaust passage 40, for example, an exhaust gas purifying three-way catalyst 60 in which platinum, palladium or the like is applied to a carrier such as alumina or ceria is disposed. A linear air-fuel ratio sensor 51 having a linear output characteristic with respect to the pre-catalyst air-fuel ratio is disposed upstream of the catalyst 60. An O2 sensor 52 that outputs a switching signal for identifying whether the post-catalyst air-fuel ratio is richer or leaner than the stoichiometric (stoichiometric air-fuel ratio) is disposed downstream of the catalyst 60.

  A fuel injection valve 30 provided for each cylinder of the engine 10 is connected to a fuel tank 53. The fuel inside the fuel tank 53 is regulated to a predetermined fuel pressure by a fuel supply mechanism including a fuel pump 54 and a fuel pressure regulator 55 and supplied to the fuel injection valve 30. The fuel injection valve 30 is driven to open by a fuel injection pulse signal having a duty (pulse width: corresponding to valve opening time) corresponding to an operating state such as an engine load supplied from the ECU 100, for example. An amount of fuel corresponding to is injected toward the intake port 29.

  Further, the engine 10 includes a cylinder deactivation control valve 80. The cylinder deactivation control valve 80 switches between the open / close driving state and the closed / fixed state described above. The cylinder deactivation control valve 80 is disposed in each cylinder, and can switch between the open / close drive state and the closed / fixed state described above for each cylinder by a drive signal from the ECU 100.

  The ECU 100 has a communication function with another control unit mounted on the vehicle, for example, an ATC / U 90 that controls the shift of the transmission. The ECU 100 controls the engine 10 in cooperation between these control units by transmitting and receiving data to and from other control units using a communication function. The ECU 100 incorporates a microcomputer for performing various controls of the engine 10, for example, fuel injection control (air-fuel ratio control) by the fuel injection valve 30 and ignition timing control by the spark plug 39.

  FIG. 2 shows an internal configuration of the engine control device.

  In the CPU 201 built in the ECU 100, an electric signal of each sensor installed in the engine 10 is converted into a signal for digital calculation processing, and a control signal for digital calculation is converted into an actual actuator drive signal. A / O unit 202 is provided. The I / O unit 202 includes a water temperature sensor 49, a cam angle sensor 25, a linear air-fuel ratio sensor 51, an O2 sensor 52, an air flow sensor 50, a throttle opening sensor 73, an accelerator opening sensor 71, The detection signals from the intake pipe pressure sensor 48 and the crank angle sensor 47 are input. Further, the I / O unit 202 is connected to a communication signal with another control unit mounted on the vehicle, for example, an AT C / U 90 that controls transmission shift.

  An output signal from the CPU 201 is sent via an output signal driver 203 to the first to fourth fuel injection valves 30 to 33, the first to fourth ignition coils 34 to 37, the electric throttle motor 72, and the first to fourth cylinders. It is sent to the pause control valves 80-83. Note that control data is sent from the I / O unit 202 to the output signal driver 203, and the output data is output when the control data is set in the output signal driver 203.

  FIG. 3 shows a detailed control block of the control apparatus for the engine shown in FIG. Hereinafter, details of each control block will be described.

  A block 301 is a block of a driving operation amount detection unit. In this embodiment, the driving operation amount detector 301 calculates the driver's accelerator opening (driving operation amount) from the detection signal of the accelerator opening sensor 71.

  A block 302 is a block of an engine speed calculation unit (operation state detection unit). The engine speed calculation unit 302 counts the electric signal of the crank angle sensor 47 set at a predetermined crank angle position of the engine 10, mainly the number of inputs per unit time of the pulse signal change, and performs arithmetic processing. The number of revolutions (operation state amount) of the engine 10 per unit time is calculated.

  A block 303 is a block of an external required torque detecting unit that calculates an external required torque from received data by communication with another control unit mounted on the vehicle, for example, the ATC / U 90 that performs transmission shift control. When shifting, the A / TC / U 90 makes a torque reduction request to the ECU 100 to temporarily reduce the torque generated by the engine in order to reduce shift shock.

  Block 304 is a block of the cylinder inflow air amount calculation unit. A cylinder inflow air amount calculation unit (operation state detection unit) 304 is configured to detect a detection signal of the air flow sensor 50 set upstream of the intake system of the engine 10 and a detection signal of the intake pipe pressure sensor 48 set in the intake passage 20. Based on the input, the cylinder inflow air amount (operation state amount) is calculated. Further, the cylinder inflow air amount calculation unit 304 calculates the load (operating state amount) of the engine 10 based on the above-described cylinder inflow air amount and the engine speed.

  A block 305 is a block of a driver request torque calculation unit that calculates a driver request torque (command value) requested by the driver based on the accelerator opening of the driver and the engine speed described above.

  A block 306 is a block of a target torque calculation unit that calculates a target torque based on the driver request torque and the external request torque described above. There are two target torques, a target SLOW torque and a target FAST torque. The target SLOW torque is mainly used for the electric throttle motor 72, and the target FAST torque is used for controlling the cylinder deactivation control valve 80 and the ignition timing.

  A block 307 is a block of an estimated generated torque calculation unit (estimated operating state change amount calculation unit) that calculates an estimated generated torque based on the engine speed and the engine load described above. Note that the estimated generated torque is an estimated torque generated by the engine 10.

  A block 308 calculates a torque reduction request value based on the target FAST torque and the estimated generated torque described above, and torque reduction for calculating the number of cylinders to be deactivated, which will be described later, and an ignition reduction amount (retard correction amount). This is a block of the request amount calculation unit.

  Block 309 is a block of the basic fuel amount calculation unit. The basic fuel amount calculation unit 309 is based on the engine speed calculated by the engine speed calculation unit 302 described above and the engine load calculated by the cylinder inflow air amount calculation unit 304 described above. Calculate 10 required basic fuel quantities.

  A block 310 is a block of a target air-fuel ratio calculation unit that determines a target air-fuel ratio of the target engine 10 based on the engine speed and the engine load described above.

  A block 311 calculates an air-fuel ratio feedback correction coefficient based on the difference between the output of the linear air-fuel ratio sensor 51 set in the exhaust passage 40 of the engine 10 and the target air-fuel ratio, and the aforementioned engine speed and engine load. This is a block of an air-fuel ratio correction coefficient calculation unit.

  Block 312 is a block of a basic ignition timing calculation unit that determines an optimal basic ignition timing in each operation region of the engine 10 based on the above engine speed and the above engine load.

  A block 313 is a block of an ISC control unit that calculates a target rotational speed during idling and calculates a target flow rate in order to keep the idling rotational speed of the engine 10 constant.

  A block 314 calculates a target throttle opening (command value) based on the load torque corresponding to the target flow rate obtained by the ISC control unit 313, the aforementioned target SLOW torque, the number of idle cylinders, and the engine speed. This is a block of a target throttle opening calculation unit.

  A block 315 is a block of a deactivated cylinder selection unit that selects a cylinder number for performing cylinder deactivation according to the number of deactivated cylinders described above.

  Block 316 is a block of the fuel injection amount calculation unit. The fuel injection amount calculation unit 316 corrects the basic fuel amount calculated by the basic fuel amount calculation unit 309 based on the water temperature of the engine 10 and the air-fuel ratio feedback coefficient of the air-fuel ratio correction coefficient calculation unit 311 described above. Then, the fuel injection amount of the cylinder that performs the cylinder deactivation described above is set to be equivalent to the fuel cut.

  The block 317 as the “cancellation unit” is, for example, a final ignition timing calculation unit that corrects the basic ignition timing determined by the basic ignition timing calculation unit 312 based on the water temperature of the engine 10 and the amount of ignition reduction. It is a block.

  A block 318 is a block of an electric throttle control unit (propulsion force control unit) as a “control unit”. The electric throttle control unit 318 controls the throttle valve 70 so as to achieve the target throttle opening described above.

  A block 319 is a cylinder deactivation control unit for deactivating the cylinder by driving the cylinder deactivation control valve 80 with respect to the cylinder performing the deactivation of the cylinder.

  A block 320 is a fuel injection control unit that controls the fuel supply to the engine 10 based on the fuel amount calculated by the fuel injection amount calculation unit 316 described above.

  The block 321 is an ignition control unit that controls the fuel mixture flowing into the cylinder 11 to be ignited according to the final ignition timing requested by the engine 10 obtained by the final ignition timing calculation unit 317 described above.

  FIG. 4 shows a control block for torque reduction by the engine control device.

  The driver request torque 401 is obtained by the engine speed calculation unit 302 based on the signal of the crank angle sensor 47 by detecting the accelerator operation amount operated by the driver's intention as the accelerator opening amount by the driving operation amount detection unit 301. It is calculated based on the engine speed.

  The external required torque 402 is calculated based on received data by communication with another control unit mounted on the vehicle, for example, the ATC / U 90 that controls the shift of the transmission.

  The target SLOW torque 404 is obtained based on the driver request torque 401. The target FAST torque 405 is obtained based on the driver request torque and the external request torque.

  The target FAST torque 405 is set to the external request torque 402 if there is a request for torque reduction from another control unit, and to the driver request torque 401 if there is no request for torque reduction.

  The estimated generated torque 403 is obtained based on the engine load and the rotational speed described above. The estimated generated torque 403 indicates the torque that the engine 10 is generating at that time.

  Torque reduction request value 406 is calculated based on a calculation result obtained by dividing target FAST torque 405 by estimated generated torque 403.

  The cylinder deactivation number 407 is calculated based on the number of cylinders approximate to the torque reduction request value 406.

  The ignition reduction amount 408 is calculated based on an ignition retard amount that is a torque reduction amount obtained by subtracting the torque corresponding to the cylinder deactivation number from the torque reduction request value 406.

  The target throttle opening 409 is calculated based on the value obtained by removing the torque corresponding to the cylinder deactivation number from the target SLOW torque 404, the total torque corresponding to the target flow rate obtained by the ISC control unit 313, and the engine speed. Is done.

  The idle cylinder selection 410 selects a cylinder number for performing cylinder idle when the number of idle cylinders is 1 or more. The cylinder deactivation is selected with priority given to the cylinder that is in the most recent intake stroke among the cylinders.

  FIG. 5 shows the timing for selecting the idle cylinder.

  In the example of FIG. 5, when selecting the idle cylinder at point A, the cylinder that is the most recently used for the intake process is preferentially selected.

  Returning to FIG. The fuel injection amount 411 is calculated based on a correction coefficient obtained based on the water temperature detected by the water temperature sensor 49, an air-fuel ratio feedback coefficient, and a basic fuel amount. When the corresponding cylinder is selected as a deactivated cylinder, the fuel injection amount 411 sets a fuel amount corresponding to a fuel cut.

  The final ignition timing 412 is calculated based on the correction amount obtained based on the water temperature detected by the water temperature sensor 49, the basic ignition timing, and the retard correction amount obtained based on the ignition reduction amount 408.

  FIG. 6 is a chart showing the behavior of torque reduction control by the engine control device. This figure shows the behavior when the vehicle receives a torque reduction request by the external required torque when the vehicle is traveling at a constant speed.

  Torque reduction request value 601 accepts a torque reduction request by external request torque at point A, the target FAST torque decreases stepwise, and continues to that value until point C, then there is no torque reduction request with a constant gradient The behavior gradually changed to the point F of the state is shown.

  The torque reduction request value 601 is calculated based on the target FAST torque and the estimated generated torque (not shown) as described above. In this chart, the number of cylinder deactivations that approximates the torque reduction request value from point A to point D is one cylinder, and the difference (α in the figure) obtained by subtracting the torque reduction amount due to cylinder deactivation from the torque reduction request value 601. Ignition reduction amount.

  The fuel cut (F / C) 603 instructs fuel cut at the point A where the cylinder deactivation number is calculated as one cylinder, and the fuel cut is performed at the point D when the torque reduction request value 601 becomes less than one cylinder deactivation number. Is released.

  Cylinder deactivation 602 starts cylinder deactivation (point B) by closing and fixing the intake valve 21 of the cylinder that is initially in the intake process after point A described above, and then the torque reduction request value 601 is the cylinder deactivation number 1 cylinder The cylinder deactivation is canceled at point D, which is less than the value.

  The throttle valve opening 604 is after the throttle valve opening corresponding to one cylinder of the deactivated cylinder is closed so that the cylinder intake air amount other than the cylinder deactivated cylinder at the point A described above is equivalent to no torque reduction request. The throttle valve opening before point A is returned to point D when cylinder deactivation is cancelled. Here, the solid line in the chart indicates the target throttle opening, and the dotted line indicates the actual throttle opening behavior. Since the throttle valve 70 is driven by the electric throttle motor 72 based on the target throttle opening, the behavior shown by the dotted line is obtained.

  The intake pipe pressure 605 indicates the behavior of the pressure in the collector 27 provided in the intake passage 20 of the engine 10 described above. As for the intake pipe pressure 605, the air corresponding to one cylinder that has performed cylinder deactivation from the collector 27 at the point B where the cylinder deactivation is started is not sucked into the cylinder. For this reason, the intake pipe pressure 605 temporarily rises from the point B, and then the amount of air passing through the throttle valve 70 and flowing into the collector 27 and the amount of air sucked into the cylinders of cylinders not in the cylinder deactivation state are It changes to C point which becomes an equilibrium state. Further, the intake pipe pressure 605 changes from a point D at which cylinder deactivation is canceled to a point E at which an equilibrium state is reached after being temporarily reduced for the same reason as described above.

  The behavior of the ignition reduction amount 608 is shown. Here, the ignition correction amounts (1) and (2) indicate the breakdown of the above-mentioned ignition reduction amount, and the sum of the ignition correction amounts (1) and (2) is the ignition reduction amount 608. The behavior of the ignition reduction amount 608 will be described using the ignition correction amount (1).

  The ignition correction amount (2) 607 indicates an ignition reduction amount 608 corresponding to the above-described fluctuation of the intake pipe pressure 605, and the ignition correction amount (1) 606 indicates an ignition reduction amount 608 other than the above-described fluctuation. .

  The ignition correction amount (1) 606 is an ignition retard amount indicated by α in the drawing that reduces the torque corresponding to α shown in the chart of the torque reduction request value 601 at the point A described above. The ignition correction amount (1) 606 maintains one cylinder at the C point. The ignition correction amount (1) 606 decreases to point D according to a change in the torque reduction request value 601. At point D, the torque reduction request value 601 becomes less than one cylinder, and cylinder deactivation is released. Therefore, the ignition correction amount (1) 606 changes stepwise to an ignition retard amount corresponding to the torque for one cylinder, and thereafter, the ignition retard amount corresponding to the torque reduction request value is calculated, and the torque reduction request At the point F where the value becomes zero, the ignition correction amount (1) also becomes zero.

  The ignition correction amount (2) 607 is an ignition retard amount corresponding to a torque reduction value that cancels the torque increase accompanying the increase in the intake pipe pressure 605 in the collector 27 from the point B where the cylinder deactivation is started to the point C described above. Is calculated. Further, the ignition correction amount (2) 607 is an ignition that reduces the ignition reduction amount 608 so as to cancel out the torque decrease accompanying the decrease in the intake pipe pressure 605 from the point D where the cylinder deactivation is released to the point E described above. A correction amount is calculated.

  The sum of the ignition correction amount (1) 606 and the ignition correction amount (2) 607 obtained as described above is calculated as the ignition reduction amount 608.

  Note that the estimated generated torque (not shown) is calculated based on the dynamics obtained based on the volume of the collector 27 and the intake air amount of the engine 10 per unit time, and thus a value reflecting the change in the intake pipe pressure Is calculated. The response of the estimated generated torque may be verified by the actual intake pipe pressure and onboard.

  FIG. 7 shows an overall control flow of the engine control apparatus according to the present embodiment. This control flow shows each control logic in a simplified manner, and detailed description of control logic not related to this embodiment is omitted.

  In FIG. 7, in step 701, an accelerator opening ratio is converted and read based on the output voltage of the accelerator opening sensor 71.

  In step 702, the number of electrical signals of the crank angle sensor 47, mainly the number of inputs per unit time of pulse signal change, is counted, and the engine speed is calculated by arithmetic processing.

  In step 703, the external required torque is calculated based on the received data by communication with another control unit mounted on the vehicle, for example, the ATC / U 90 that performs transmission shift control of the transmission.

  In step 704, the cylinder inflow air amount and the engine load are calculated based on the air flow rate converted between the voltage and the flow rate based on the output voltage of the air flow sensor 50 and the engine speed.

  In step 705, a driver request torque (command value) requested by the driver is calculated based on the accelerator opening ratio of the driver and the engine speed described above.

  In step 706, a target SLOW torque and a target FAST torque are calculated based on the driver request torque and the external request torque.

  In step 707, the estimated generated torque is calculated based on the engine speed and the engine load.

  In step 708, the number of idle cylinders and the amount of ignition reduction are calculated from the torque reduction request value 502 obtained based on the estimated generated torque and the target FAST torque.

  In step 709, the target value of the idle speed and the target flow rate of the ISC that can realize the target value of the idle speed are calculated.

  In step 710, a target throttle opening (command value) is calculated based on the aforementioned target SLOW torque, the number of idle cylinders, the ISC target flow rate, and the engine speed.

  In step 711, the electric throttle control unit 318 is output so that the target throttle opening is obtained.

  In step 712, when the number of deactivated cylinders is 1 or more, a cylinder to be deactivated is determined. The idle cylinder includes at least a cylinder that becomes an intake process most recently. Further, a combination of cylinder numbers in which the idle cylinders are not consecutive in the ignition order may be selected (for example, when the ignition order is 4 → 1 → 3 → 4 → 2 cylinders and the idle cylinder is 2 cylinders, When the cylinder that is the intake process is the first cylinder, the first cylinder and the fourth cylinder are selected).

  In step 713, information on the cylinder number for performing the determined deactivation cylinder is output to the cylinder deactivation control unit 319.

  In step 714, the basic fuel amount is calculated based on the engine speed and the intake air amount (engine load).

  In step 715, a map search is performed for the target air-fuel ratio based on the engine speed and the engine load.

  In step 716, based on the output voltage of the linear air-fuel ratio sensor 51, the actual air-fuel ratio converted by the air-fuel ratio is read.

  In step 717, feedback control to the target air-fuel ratio is performed based on the target air-fuel ratio and the actual air-fuel ratio, and an air-fuel ratio correction coefficient is calculated.

  In step 718, based on the air-fuel ratio correction coefficient by feedback control and the water temperature, the basic fuel amount is corrected by the calculated water temperature correction coefficient, and the fuel injection amount 411 is calculated.

  In step 719, the fuel injection amount 411 is output to the fuel injection control unit 320.

  In step 720, the basic ignition timing is calculated based on the engine speed and the engine load.

  In step 721, the water temperature is corrected for the basic ignition timing, and the final ignition timing is calculated.

  In step 722, the final ignition timing is output to the ignition control unit 321.

  FIG. 8 and FIG. 9 are flowcharts for obtaining the torque reduction request value and the output of each control unit, and are executed every predetermined time.

  Here, before the processing of the flowcharts shown in FIGS. 8 and 9 is executed, reading of each sensor described in FIG. 3 is performed.

  First, in step 801, the driver request torque Tdrq is calculated based on the accelerator opening and the engine speed calculated by the engine speed calculation unit 302.

  FIG. 10 shows a map for calculating the driver request torque.

  The driver request torque Tdrq is obtained from a map of the accelerator opening and the engine speed Ne as shown in FIG.

  Returning to FIG. In step 802, communication data received from another control unit is checked to check whether or not external request torque data has been received. If received, the external request torque Texrq is updated.

  In step 803, a pump loss torque Tpu corresponding to the pump loss of the engine 10 and a load torque Tls corresponding to the power for driving the auxiliary equipment around the engine 10 are added to the driver required torque Tdrq to obtain the target SLOW torque Tsrq. Ask.

  In step 804, if the above-mentioned external required torque data has been received (S804: YES), the process proceeds to step 805, and if not received (S804: NO), the process proceeds to step 806.

  In step 805, the updated external request torque Texrq described above is substituted for the target FAST torque Tfrq.

  In step 806, the driver request torque Tdrq is substituted for the target FAST torque Tfrq.

  In step 807, the estimated generated torque Tetm is calculated by multiplying the value obtained by dividing the cylinder inflow air amount Qa by the engine speed Ne and the torque conversion coefficient Ktq.

  In step 808, the target FAST torque Tfrq is divided by the estimated generated torque Tetm to calculate a torque reduction value Tred.

  FIG. 11 shows a table for searching for the number of deactivated cylinders.

  Returning to FIG. In step 809, the table search shown in FIG. 11 is performed using the torque reduction request value Tred, the approximate number of cylinders is obtained, and the number of deactivated cylinders Nfcy is calculated.

  FIG. 12 shows a table for searching for the ignition reduction amount Ard.

  Returning to FIG. In step 810, after obtaining a calculation value A obtained by excluding the torque reduction amount obtained by executing the cylinder deactivation of the deactivation cylinder number Nfcy from the torque reduction request value Tred, a table search shown in FIG. 12 is performed to determine the ignition reduction amount. Calculate Ard. The ignition reduction amount Ard indicates the retard amount of the ignition timing.

  FIG. 13 shows a table for searching for the target rotation speed Ntgt.

  In step 901 shown in FIG. 9, the table search shown in FIG. 13 is performed using the water temperature Tw to calculate the target rotational speed Ntgt so that the engine rotational speed becomes the target rotational speed Ntgt when the operating state is idle. To control. Next, in step 901, the target flow rate Qisc is calculated by multiplying the deviation obtained from the engine speed Ne and the target speed Ntgt by the air amount conversion coefficient Kisc.

  In step 902, a calculated value B obtained by removing a torque reduction amount obtained by performing cylinder deactivation of the number of deactivation cylinders Nfcy from the target SLOW torque Tsrq is obtained. Next, in step 902, a map search is performed using the calculated value C obtained by multiplying the target flow rate Qisc by the torque conversion coefficient Ktisc to the calculated value B and the engine speed Ne, and the target throttle opening degree is obtained. Calculate Tgth. The aforementioned map search is obtained using the map shown in FIG.

  In step 903, as described with reference to FIG. 7, when the number of deactivated cylinders is 1 or more, a cylinder to be deactivated is selected. The idle cylinder includes at least a cylinder that becomes an intake process most recently. For other idle cylinders, combinations of cylinder numbers that are not consecutive in the firing order may be selected.

  In step 904, a basic fuel amount Tp is calculated by multiplying a value obtained by dividing the cylinder inflow air amount Qa by the engine speed Ne and a fuel injection amount conversion coefficient Kinj.

  In step 905, the fuel injection amount Tiout_n of each cylinder is calculated. An invalid pulse width Ts at which fuel is not injected from the fuel injection valve 30 is set for the cylinder that performs cylinder deactivation, and an air-fuel ratio feedback coefficient Kfb and a correction coefficient Ktw based on water temperature are added to the basic injection amount Tp for the other cylinders Multiply and find the invalid injection pulse width Ts.

  In step 906, a map (not shown) is searched based on the engine speed Ne and the engine load LDATA to obtain the basic ignition timing Astd.

  In step 907, the correction coefficient Ktwa is corrected by the water temperature to the basic ignition timing Astd, the ignition reduction amount Ard is corrected to the retard side, and the final ignition timing Adv_n of each cylinder is obtained.

  In step 908, the battery voltage (not shown) VB is read, and the energization time Tdwl of the ignition coil is obtained by table search.

  As described above, parameters to be output to each control unit are obtained.

  The processing of each control unit 318 to 321 described in FIG. 3 will be described using the flowcharts shown in FIGS. 14 to 17.

  FIG. 14 shows a flowchart of processing of the electric throttle control unit 318 executed every predetermined time.

  In step 1401, the target throttle opening Tgth is read.

  In step 1402, the duty ratio [%] of the electric throttle motor drive signal Pduty is calculated based on the ratio of the target throttle opening Tgth to the operating angle range Thmax of the throttle valve 70.

  In step 1403, the aforementioned drive signal is output to the electric throttle motor 72.

  FIG. 15 is a flowchart showing processing of the fuel injection unit 320 that is executed for each predetermined crank angle.

  In step 1501, the cylinder number Ninj for the intake process is selected to determine the cylinder number for fuel injection.

  In step 1502, the fuel injection amount Tiout_n of the Ninj cylinder is read and converted into a fuel injection valve drive signal.

  In step 1503, the fuel injection valve drive signal is output to the fuel injection valve 30 of the Ninj cylinder.

  FIG. 16 shows a flowchart of the processing of the cylinder deactivation control unit 319 executed for each predetermined crank angle.

  In step 1601, the cylinder number Ninj for the intake process is selected, and the cylinder number for operating the cylinder deactivation control valve 80 is determined.

  In Step 1602, if the Ninj cylinder is selected as the idle cylinder described in Step 713 of FIG. 7 (S1602: YES), the process proceeds to Step 1603. Otherwise, the process proceeds to Step 1604.

  In step 1603, the cylinder deactivation control valve 80 of the Ninj cylinder is driven to the cylinder deactivation state, and the intake valve 21 and the exhaust valve 22 are operated to be closed and fixed.

  In step 1604, the cylinder deactivation control valve 80 of the Ninj cylinder is driven to the cylinder deactivation release state, and the intake valve 21 and the exhaust valve 22 are operated to perform an opening / closing operation.

  FIG. 17 shows a flowchart of processing of the ignition control means executed at the timing when the energization to the ignition coil of each cylinder is turned off (end of energization).

  In step 1701, the cylinder number Nadv in which the energization of the ignition coil 34 is turned off is read.

  In Step 1702 and Step 1703, the time Ton until the start of energization of the ignition coil 34 of the Nadv cylinder and the energization end based on the final ignition timing Adv_n and the ignition coil energization time Tdwl described in Steps 907 and 908 of FIG. Calculate the time to Toff.

  In step 1704, a drive signal is output to the ignition coil 34 by setting the above-described Ton and Toff in a timer for driving the ignition coil of the Nadv cylinder.

  The control device for the engine 10 in this embodiment receives a request to reduce the output torque of the engine 10 and deactivates the cylinders corresponding to the number of cylinders that approximate the torque reduction request value 406. The control device of the engine 10 includes a throttle valve 70, an electric throttle motor 72, and an electric throttle control unit 318. The throttle valve 70 and the electric throttle motor 72 adjust the amount of air taken in by the engine 10. The electric throttle control unit 318 controls the throttle valve 70 and the electric throttle motor 72 so that the amount of air sucked into the engine 10 becomes the amount of intake air corresponding to the number of cylinder deactivations. In the meantime, thermal deterioration of the catalyst 60 can be prevented, and fuel consumption and torque can be reduced quickly and accurately.

  Furthermore, since it has the final ignition timing calculation unit 317 that corrects the ignition timing of the engine 10 so as to offset the difference (deviation) between the torque reduction request value 601 and the torque reduction value, the torque reduction request value 601 Thus, the difference from the torque reduction value due to cylinder deactivation can be easily eliminated without changing the structure of the engine 10.

  Further, the final ignition timing calculation unit 317 corrects the ignition timing so as to cancel out the change in the output torque due to the change in the number of cylinder deactivations and the change in the intake air amount due to the throttle operation. The difference between 601 and the torque reduction value due to cylinder deactivation can be eliminated efficiently in terms of fuel consumption and torque.

  Further, the electric throttle control unit 318 controls the throttle valve 70 and the electric throttle motor 72 so that the intake air amount corresponding to the idle cylinder is obtained, and the final ignition timing calculation unit 317 outputs torque associated with cylinder idle. Since the ignition timing is corrected so as to offset the reduction in the intake air amount and the reduction in the intake air amount due to the throttle operation, the fuel consumption and torque are reduced while preventing the catalyst 60 from thermal degradation when the cylinder is stopped. can do.

  Further, the electric throttle control unit 318 controls the throttle valve 70 and the electric throttle motor 72 so that the intake air amount corresponds to the return from the deactivated cylinder, and the final ignition timing calculation unit 317 starts from the cylinder deactivated state. Since the ignition timing is corrected so as to offset the reduction in the output torque accompanying the return of the engine and the reduction in the intake air amount due to the throttle operation, the thermal degradation of the catalyst 60 is prevented when returning the cylinder deactivation, Fuel consumption and torque can be reduced.

  Furthermore, since the change in the output torque of cylinder deactivation and cylinder deactivation recovery is estimated based on the timing of the intake stroke of the engine 10, the driving force can be obtained without delay when the deactivation cylinder is reinstated.

10: Engine 70: Throttle valve 72: Electric throttle motor 317: Final ignition timing calculation unit 318: Electric throttle control unit 406: Torque reduction required value

Claims (6)

An engine control apparatus that receives a request for engine output torque reduction and deactivates a number of cylinders approximating a torque reduction request value,
An intake air amount adjusting mechanism for adjusting the amount of air taken in by the engine;
An engine control apparatus comprising: a control unit that controls the intake air amount adjusting mechanism so that an air amount taken into the engine becomes an intake air amount corresponding to a cylinder deactivation number. A canceling unit that corrects the ignition timing of the engine so as to cancel the difference between the torque reduction request value and the torque reduction value;
The engine control apparatus according to claim 1. The canceling unit corrects the ignition timing so as to cancel out a change in output torque accompanying a change in the cylinder deactivation number and a change in the intake air amount accompanying a throttle operation;
The engine control device according to claim 2. The control unit controls the intake air amount adjusting unit so that the intake air amount corresponds to the cylinder deactivation,
The canceling unit corrects the ignition timing so as to cancel the reduction in the output torque due to the cylinder deactivation and the reduction in the intake air amount due to the throttle operation.
The engine control device according to claim 2 or 3. The control unit controls the intake air amount adjusting unit so that the intake air amount corresponds to the return from the cylinder deactivation;
The canceling unit corrects the ignition timing so as to cancel out the increase in the output torque accompanying the return from the cylinder deactivation and the increase in the intake air amount due to the throttle operation;
The engine control device according to any one of claims 2 to 4. The change in the output torque of the cylinder deactivation and the cylinder deactivation return is estimated based on the intake stroke timing of the engine.
The engine control device according to any one of claims 1 to 5.

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