JP2016125351A - Rotation stop position controlling apparatus of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably stop a rotating shaft at a predetermined rotation position suitable for restart of an engine, when stopping the engine.SOLUTION: A rotation speed sensor 45 detects a rotation position and a rotation speed of a rotating shaft 3. An ECU 50, for stopping the rotating shaft 3 at a predetermined rotation position, controls each injector 32 such that a fuel cut in an intake stroke of each cylinder 2 is sequentially started from a specific cylinder 2. The ECU 50 requests the fuel cut when stopping the rotating shaft 3 at the predetermined rotation position. When the detected rotation position at the time of the request is within a predetermined range to allow the fuel cut in the next intake stroke of the specific cylinder 2, the ECU controls the injector 32 to start the fuel cut in the next intake stroke of the specific cylinder 2, and when the detected rotation position is out of the predetermined range to allow the fuel cut in the next intake stroke of the specific cylinder 2, the ECU controls the injector 32 to retard the fuel cut to an intake stroke after the next intake stroke of the specific cylinder 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine rotation stop position control device configured to control a rotation stop position of a rotation shaft of an engine when the engine is stopped.

  Conventionally, as a technology in this type of field, for example, an internal combustion engine control device described in Patent Document 1 below is known. This device is employed in an idle stop system that automatically stops and automatically starts the engine. Here, in order to improve the restartability of the engine, when the engine automatically stops (idle stop) during idle operation, the engine rotation stop position (stop crank angle) is controlled to a crank angle range suitable for restart. It is like that. That is, when the engine is stopped, fuel is injected from the injector into the cylinder in the expansion stroke and ignited and burned, so that the engine can be restarted with the power of the engine itself without borrowing the power of the starter motor. Start. Therefore, when an idle stop request (fuel cut request) is input, fuel cut is started from a specific cylinder among the plurality of cylinders, and idle stop is performed.

JP 2006-104955 A

  However, in the technique described in Patent Document 1, when a fuel cut request is entered, the time until the fuel cut is started in a specific cylinder may be too short. There was a case. As a result, when stopping the engine, the crankshaft may not be able to be stopped at a predetermined rotational position suitable for restarting the engine.

  The present invention has been made in view of the above circumstances, and its object is to stably stop the rotating shaft at a predetermined rotational position suitable for restarting the engine when the engine is stopped. An object of the present invention is to provide an engine rotation stop position control device.

  In order to achieve the above object, an invention according to claim 1 is an engine rotation stop position control device for controlling an engine rotation shaft to stop at a predetermined rotation position, the engine comprising a plurality of cylinders. The reciprocating engine includes: a reciprocating engine configured to rotate the rotation shaft by burning the fuel supplied by the fuel supply means in each cylinder; and the fuel supply means supplies fuel to each cylinder. And a rotation detection means for detecting the rotation position and rotation speed of the rotation shaft, and in order to stop the rotation shaft at a predetermined rotation position, the fuel supply is stopped from a specific cylinder for each cylinder. In the engine rotation stop position control device comprising control means for controlling the fuel supply means so as to start sequentially, the control means stops the fuel when the rotation shaft is stopped at a predetermined rotation position. If the rotation position detected by the rotation detection means is within a predetermined range that allows the stop of fuel supply in a specific stroke next time for a specific cylinder at the time of the request, specify The fuel supply means is controlled to start the fuel supply stop in the next specific stroke of the cylinder of the cylinder, and when the detected rotational position is not within the predetermined range, the start of the fuel supply stop is specified. The purpose is to control the fuel supply means so as to delay until a certain specific stroke one after the other.

  According to the configuration of the invention described above, when the engine is stopped, the control means specifies the stop of fuel supply by the fuel supply means in a specific stroke of each cylinder in order to stop the rotating shaft at a predetermined rotational position. The fuel supply means is controlled so as to start sequentially from the cylinder. Thereby, rotation of a rotating shaft begins to stop and a rotating shaft stops in a predetermined rotation position. Here, when stopping the fuel supply, when the rotational position of the rotating shaft is within a predetermined range at the time of the request, the fuel supply is stopped at the next specific stroke for the specific cylinder. On the other hand, when stopping the fuel supply, if the rotational position of the rotating shaft is not within the predetermined range at the time of the request, the fuel supply is stopped after waiting for a specific stroke of the specific cylinder one after another. Therefore, even if the fuel supply stop request timing comes just before a specific stroke, the fuel supply stop is always started in a specific stroke for a specific cylinder. Stop at position.

  In order to achieve the above object, the invention described in claim 2 is the invention described in claim 1, wherein the specific stroke is an intake stroke.

  According to the configuration of the above invention, in addition to the operation of the invention described in claim 1, even if the request timing for stopping the fuel supply enters just before the intake stroke, the stop of the fuel supply is always the intake air for a specific cylinder. Since it starts in the stroke, the rotation axis is always stopped at a predetermined rotation position.

  In order to achieve the above object, according to a third aspect of the present invention, in the first or second aspect of the present invention, the ignition means for igniting the fuel supplied to each cylinder, and the ignition timing by the ignition means. Ignition timing control means for controlling the ignition timing control means, the ignition timing control means, when the control means has requested to stop the fuel supply, the rotation speed detected by the rotation detection means does not reach a predetermined target rotation speed The purpose is to change and control the ignition timing by the ignition means in order to adjust the rotation speed of the rotating shaft until the fuel supply is stopped in a specific cylinder.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 1 or 2, when the stop of fuel supply is requested and the detected rotational speed does not reach a predetermined target rotational speed, the fuel supply is performed. The ignition timing by the igniting means is changed and controlled until the stop of the rotation is started, and the rotation speed of the rotating shaft is brought close to a predetermined target rotation speed. Here, the predetermined target rotation speed is an optimum rotation speed for starting the stop of fuel supply in order to stop the rotation shaft at a predetermined rotation position.

  In order to achieve the above object, according to a fourth aspect of the invention, in the invention according to any one of the first to third aspects, the control means detects the stop of the fuel supply and then detects the rotation by the rotation detecting means. When the rotation speed to be achieved does not reach the predetermined target rotation speed, the fuel supply means is controlled so as to delay the start of the fuel supply stop.

  According to the configuration of the invention, in addition to the operation of the invention according to any one of claims 1 to 3, when the rotation speed of the rotary shaft does not reach a predetermined target rotation speed after the fuel supply stop is requested. In the meantime, the fuel supply is not stopped.

  According to the first or second aspect of the invention, when the engine is stopped, the rotating shaft can be stably stopped at a predetermined rotational position suitable for restarting the engine.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, when the engine is stopped, the rotation shaft is provided regardless of the difference in the rotation speed after the fuel supply stop is requested. It can be accurately stopped at a predetermined rotational position suitable for restarting the engine.

  According to the invention described in claim 4, in addition to the effect of the invention described in any one of claims 1 to 3, it is possible to bring the actual rotational speed of the engine closer to the target rotational speed optimum for the start of the fuel supply stop. it can.

1 is a schematic configuration diagram illustrating an engine system according to a first embodiment. The schematic diagram which concerns on 1st Embodiment and shows the structure of each cylinder. The front view which concerns on 1st Embodiment and shows the relationship between arrangement | positioning of a rotational speed sensor and a timing rotor. The flowchart which shows the content of 1st Embodiment and the rotation stop position control of an engine. The ignition timing map referred in order to obtain | require the target ignition timing according to 1st Embodiment according to the engine speed NE. The time chart which shows the behavior of (a) engine rotational speed NE, (b) crank angle, (c) fuel cut request flag XFCD, and (d) fuel cut signal (F / C signal) according to the first embodiment. The flowchart which concerns on 2nd Embodiment and shows the content of the rotation stop position control of an engine. The map referred to in order to obtain | require ignition timing correction value (DELTA) aop according to 2nd Embodiment according to rotational speed difference (DELTA) NEcf. According to the second embodiment, (a) the operation stroke (intake stroke, compression stroke, expansion stroke, exhaust stroke) of the first cylinder # 1 to the fourth cylinder # 4, (b) crank angle, (c) fuel cut signal (F / C signal), (d) Throttle opening degree TA, (e) Ignition timing, and (f) Engine speed NE.

<First Embodiment>
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an engine rotation stop position control device according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an engine system in this embodiment. In this embodiment, an engine 1 mounted on an automobile is a four-cycle reciprocating engine, and includes four cylinders 2 and a crankshaft 3 that is a rotating shaft of the present invention. The engine 1 is provided with an intake passage 4 and an exhaust passage 5. An air cleaner 6, an electronic throttle device 7, and a surge tank 8 are provided in the intake passage 4 from the upstream side. The electronic throttle device 7 includes a throttle valve 9 that is opened and closed by a motor 31 and a throttle sensor 41 for detecting an opening degree (throttle opening degree) TA of the throttle valve 9. The exhaust passage 5 is provided with a catalytic converter 10 for purifying exhaust gas.

  The engine 1 includes a cylinder block 11 and a cylinder head 12. In the cylinder block 11, a piston 13 is provided for each cylinder 2. Each piston 13 is connected to the crankshaft 3 via a connecting rod 14. Each cylinder 2 includes a combustion chamber 15. That is, in each cylinder 2, the combustion chamber 15 is formed between the piston 13 and the cylinder head 12. An intake port 16 and an exhaust port 17 communicating with each combustion chamber 15 are formed in the cylinder head 12. Each intake port 16 communicates with the intake passage 4. Each exhaust port 17 communicates with the exhaust passage 5. Each intake port 16 is provided with an intake valve 18, and each exhaust port 17 is provided with an exhaust valve 19. Each intake valve 18 and each exhaust valve 19 are linked to the rotation of the crankshaft 3, that is, linked to the vertical movement of each piston 13, and thus a series of operating strokes (intake stroke, compression stroke, expansion) of the engine 1. It is driven to open and close by a valve mechanism 21 including a camshaft 20 and the like in conjunction with the stroke and the exhaust stroke).

  The cylinder head 12 is provided with an injector 32 that directly injects fuel into each combustion chamber 15 corresponding to each cylinder 2. Each injector 32 corresponds to fuel supply means of the present invention, and is configured to inject and supply fuel supplied from a fuel supply device (not shown) to each corresponding combustion chamber 15. In each combustion chamber 15, a combustible air-fuel mixture is formed by the fuel injected from the injector 32 and the air sucked from the intake passage 4 in the intake stroke.

  The cylinder head 12 is provided with a spark plug 33 in each combustion chamber 15 corresponding to each cylinder 2. Each spark plug 33 receives the ignition signal output from the ignition coil 34 and performs a spark operation. Both parts 33 and 34 constitute an ignition device corresponding to the ignition means of the present invention for igniting the combustible air-fuel mixture formed in each combustion chamber 15. The combustible air-fuel mixture in each combustion chamber 15 explodes and burns by the spark operation of each spark plug 33 in the compression stroke, and the expansion stroke passes. Exhaust gas after combustion is discharged to the outside from each combustion chamber 15 through the exhaust port 17, the exhaust passage 5 and the catalytic converter 10 in the exhaust stroke. With combustion of the combustible air-fuel mixture in each combustion chamber 15, each piston 13 moves up and down, a series of operation strokes advance, and the crankshaft 3 rotates, whereby power is obtained in the engine 1. In the engine 1, the crankshaft 3 rotates twice (720 ° A rotation) every time a series of operation strokes is completed once in each cylinder 2.

  FIG. 2 schematically shows the configuration of each cylinder 2. As the crankshaft 3 rotates, the piston 13 moves up and down (stroke) between a top dead center (TDC) and a bottom dead center (BDC). The distance between the top dead center (TDC) and the bottom dead center (BDC) is the maximum stroke STmax of the piston 13.

  The cylinder head 12 is provided with an in-cylinder pressure sensor 42 for detecting the pressure in each combustion chamber 15 as the in-cylinder pressure PS corresponding to each cylinder 2.

  As shown in FIG. 1, various sensors 41 to 47 provided in the engine 1 constitute an operation state detection unit for detecting the operation state of the engine 1. An accelerator sensor 43 is provided on the accelerator pedal 27 provided in the driver's seat. The accelerator sensor 43 detects the depression angle of the accelerator pedal 27 as the accelerator opening ACC, and outputs an electrical signal corresponding to the detected value. The water temperature sensor 44 provided in the engine 1 detects the temperature (cooling water temperature) THW of the cooling water flowing inside the cylinder block 11 and outputs an electrical signal corresponding to the detected value. A rotational speed sensor 45 provided in the engine 1 detects the rotational position (crank angle) and rotational speed (engine rotational speed) NE of the crankshaft 3, and outputs an electrical signal corresponding to the detected value. The sensor 45 is configured to detect the rotation of the timing rotor 28 fixed to one end of the crankshaft 3 for each predetermined angle. In this embodiment, the rotation speed sensor 45 and the timing rotor 28 correspond to the rotation detection means of the present invention. The intake pressure sensor 46 provided in the surge tank 8 detects the intake pressure PM in the surge tank 8 and outputs an electrical signal corresponding to the detected value. The oxygen sensor 47 provided in the exhaust passage 5 detects the oxygen concentration (output voltage) Ox in the exhaust gas discharged to the exhaust passage 5, and outputs an electrical signal corresponding to the detected value.

  The rotation detection means of this embodiment will be described in detail. FIG. 3 is a front view showing the relationship between the arrangement of the rotation speed sensor 45 and the timing rotor 28. In FIG. 3, the rotation speed sensor 45 is constituted by a crank sensor made of an MR element, and is disposed to face the outer periphery of the timing rotor 28 fixed to one end of the crankshaft 3. A plurality of protrusions (teeth) 28a are formed on the outer periphery of the timing rotor 28, and the rotation speed sensor 45 is disposed so as to face each tooth 28a. Most of the plurality of teeth 28a are formed, for example, every 10 ° C., and are missing teeth 28b formed at intervals of 30 ° C. at only one place. The rotation speed sensor 45 detects the passage of each tooth 28a and outputs a pulse signal when the timing rotor 28 rotates as the crankshaft 3 rotates. The engine speed NE can be obtained from the elapsed time between successive pulse signals.

  The engine system includes an electronic control unit (ECU) 50 that performs various controls. Various sensors 41 to 47 are connected to the ECU 50. The ECU 50 is connected to a motor 31, injectors 32, and ignition coils 34, respectively.

  In this embodiment, the ECU 50 inputs signals output from the various sensors 41 to 47, and performs the fuel injection control, the ignition timing control, the idling stop control, and the like based on these signals, and the motor 31 and each injector 32. In addition, each ignition coil 34 is controlled. In this embodiment, the ECU 50 corresponds to the control means of the present invention.

  Here, the fuel injection control is to control the fuel injection amount and the injection timing by each injector 32 in accordance with the operating state of the engine 1. The ignition timing control is to control the ignition timing by each ignition plug 33 by controlling each ignition coil 34 according to the operating state of the engine 1. The idling stop control means that when a predetermined automatic stop condition is satisfied, the fuel supply by each injector 32 is stopped to automatically stop the engine 1, and when the predetermined restart condition is satisfied, the stop state is established. Injecting and supplying fuel from each injector 32 to each engine 1 and operating each spark plug 33 causes the fuel to burn and automatically restart the engine 1. The idling stop control includes engine rotation stop position control, which will be described later.

  As is well known, the ECU 50 includes a central processing unit (CPU), various memories, an external input circuit, an external output circuit, and the like. The memory stores a predetermined control program related to various controls of the engine 1. The CPU executes the various controls described above based on a predetermined control program based on detection signals of the various sensors 41 to 47 input via the input circuit.

  Here, the electronic throttle device 7 opens and closes in order to adjust the amount of intake air supplied to the combustion chamber 15 of each cylinder 2. In this embodiment, the electronic throttle device 7 operates to adjust the rotation of the crankshaft 3. It also functions as an adjusting means. That is, when a fuel cut is performed on the engine 1 in order to automatically stop the engine 1 from the idling operation state, the electronic throttle device 7 is operated to open the throttle valve 9 from the idling opening degree. The cylinder 2 is filled with intake air, a load is applied to the engine 1, the deceleration torque of the crankshaft 3 is changed, and the engine rotational speed NE is adjusted.

  Next, engine rotation stop position control in idling stop control will be described. FIG. 4 shows the contents from a flowchart. This control means the operation of the engine rotation stop position control device in this embodiment.

  When the process proceeds to this routine, in step 100, the ECU 50 determines whether or not a stop condition for the engine 1 is satisfied. For example, the ECU 50 can determine whether the engine rotational speed NE has been reduced to a predetermined rotational speed at which the engine 1 is to be stopped, and can be established. If the determination result is affirmative, the ECU 50 proceeds to step 110.

  In step 110, the ECU 50 requests a fuel cut and sets a fuel cut request flag XFCD to “1”.

  Next, at step 120, the ECU 50 takes in the crank angle FCDA that is the rotational position of the crankshaft 3 at the time of fuel cut request based on the detection value of the rotational speed sensor 45. In this embodiment, every time a series of operation strokes (intake stroke, compression stroke, expansion stroke, exhaust stroke) is completed once in each cylinder 2 of the engine 1, the crankshaft 3 rotates twice (720 ° A rotation). Therefore, the ECU 50 takes in the crank angle FCDA in the range of “0 to 720 ° C.”.

  Next, in step 130, the ECU 50 sets the fuel cut timing for one specific cylinder 2 of the four cylinders.

  Next, at step 140, the ECU 50 determines whether or not the crank angle FCDA at the time of the fuel cut request is within a predetermined crank angle range CA1 that allows fuel cut. As this predetermined crank angle range CA1, for example, “0 to 540 ° C. A” can be applied. When this determination result is negative, the ECU 50 waits for the crank angle FCDA at the time of the fuel cut request to be within the predetermined crank angle range CA1 in the next cycle. On the other hand, if the determination result is affirmative, the ECU 50 proceeds to step 150.

  In step 150, the ECU 50 determines whether or not the engine rotational speed NE is within a predetermined target rotational speed range TNE based on the detection value of the rotational speed sensor 45. Here, as the predetermined target rotation speed range TNE, for example, “800 to 810 rpm” can be applied. If this determination result is negative, the ECU 50 proceeds to step 160, and if this determination result is affirmative, the ECU 50 proceeds to step 190.

  In step 160, the ECU 50 determines whether or not the engine rotational speed NE is lower than a predetermined target rotational speed range TNE based on the detection value of the rotational speed sensor 45. If this determination result is affirmative, the ECU 50 proceeds to step 170. If this determination result is negative, the ECU 50 proceeds to step 180.

  In step 170, the ECU 50 advances the ignition timing. That is, the ECU 50 controls the spark plug 33 via the ignition coil 34 based on the target ignition timing advanced from the standard ignition timing. Thereafter, the ECU 50 returns the process to step 150. Here, the ECU 50 can refer to, for example, an ignition timing map as shown in FIG. 5 in order to obtain the target ignition timing according to the engine rotational speed NE. In the ignition timing map of FIG. 5, the ECU 50 can refer to characteristics in a range from an advance angle to a retard angle indicated by an arrow as the target ignition timing.

  On the other hand, in step 180, the ECU 50 retards the ignition timing. That is, the ECU 50 controls the spark plug 33 via the ignition coil 34 based on the target ignition timing retarded from the standard ignition timing. Thereafter, the ECU 50 returns the process to step 150. Here, the ECU 50 can refer to the ignition timing map as shown in FIG. 5 in the same manner as described above in order to obtain the target ignition timing according to the engine rotational speed NE.

  Then, in step 190 after proceeding from step 150, the ECU 50 determines whether or not the specific one cylinder 2 set in step 130 is the fuel cut timing. If this determination is negative, the ECU 50 returns the process to step 150. If the determination result is affirmative, the ECU 50 proceeds to step 200.

  In step 200, the ECU 50 starts fuel cut from one specific cylinder 2 in the intake stroke, and then sequentially performs fuel cut for other cylinders 2 and returns the process to step 100.

  According to the above control, when the crankshaft 3 is stopped at a predetermined crank angle, the ECU 50 requests a fuel cut, and at the time of the request, the detected crank angle is the next intake stroke for one specific cylinder 2. Is within a predetermined crank angle range CA1 in which the fuel cut is allowed, the injector 32 is controlled to start the fuel cut in the next intake stroke for the specific cylinder 2 and the detected crank angle Is not within the predetermined crank angle range CA1, the injector 32 is controlled so as to delay the start of fuel cut until the next intake stroke for one specific cylinder 2.

  Further, according to the above control, when the ECU 50 requests the fuel cut, if the detected engine rotational speed NE is not within the predetermined target rotational speed range TNE, the fuel cut is started in the specific one cylinder 2. In the meantime, in order to adjust the engine rotational speed NE, the ignition timing by the ignition device (ignition plug 33, ignition coil 34) is changed and controlled.

  Here, an example of the effect of the above control will be described with reference to FIG. FIG. 6 is a time chart showing the behavior of (a) engine speed NE, (b) crank angle, (c) fuel cut flag, and (d) fuel cut signal (F / C signal). In FIG. 6, as shown in (b), within a predetermined crank angle range CA1 between time t1 and time t3, as shown by a thick line in (c), the fuel cut request flag XFCD is “ 1 ", that is, a fuel cut request is entered. Then, as shown by a thick line in (d), the fuel cut is not started immediately, and the fuel cut signal is turned on (fuel cut start) until time t5 when the specific one cylinder 2 becomes the next intake stroke. It will be. Incidentally, it is at time t1 that the specific one cylinder 2 has reached the current intake stroke. In this case, as indicated by a thick line in (a), the engine speed NE starts to decrease from time t5. On the other hand, in FIG. 6, as shown in (b), not within the predetermined crank angle range CA1 between time t1 and time t3, but within the remaining crank angle range CA2 between time t3 and time t5, As indicated by a thick broken line in (c), the fuel cut request flag XFCD becomes “1” at time t4, that is, a fuel cut request is entered. Then, as shown by a thick broken line in (d), the fuel cut is not started immediately, and the fuel cut signal is turned on (start of fuel cut) until time t7 when one specific cylinder 2 is in the next intake stroke. It will be late. In this case, as indicated by a thick broken line in (a), the engine speed NE starts to decrease from time t7.

  According to the engine rotation stop position control apparatus in this embodiment described above, when the engine 1 is stopped, the ECU 50 causes each cylinder 2 to stop the crankshaft 3 at a predetermined rotation position (predetermined crank angle). The injector 32 is controlled so that the fuel cut by the injector 32 in the intake stroke is started sequentially from one specific cylinder 2. As a result, the rotation of the crankshaft 3 starts to stop, and the crankshaft 3 stops at a predetermined crank angle. Here, when starting the fuel cut, when the crank angle is within the predetermined crank angle range CA1 at the time of the request, the fuel cut is started for the specific one cylinder 2 in the next intake stroke. On the other hand, if the crank angle is not within the predetermined crank angle range CA1 at the time of the request, the fuel cut is started after waiting for the next intake stroke for one specific cylinder 2. Therefore, even if the request timing of the fuel cut is delayed and a request is made just before the intake stroke, the fuel cut is always started in the intake stroke of one specific cylinder 2, so that the crankshaft 3 always has a predetermined crank angle. Stop at. For this reason, when the engine 1 is stopped, the crankshaft 3 can be stably stopped at a predetermined crank angle suitable for restarting the engine 1.

  Further, in this embodiment, if the detected engine rotational speed NE is not within the predetermined target rotational speed range TNE when the fuel cut is requested, the ignition is performed until the fuel cut is actually started. The ignition timing by the device (ignition plug 33, ignition coil 34) is changed and controlled, and the engine rotational speed NE is brought close to a predetermined target rotational speed range TNE. Here, the predetermined target rotational speed range TNE is an engine rotational speed that is optimal for starting fuel cut in order to stop the crankshaft 3 at a predetermined crank angle. For this reason, when the engine 1 is stopped, the crankshaft 3 can be accurately stopped at a predetermined crank angle suitable for restarting the engine 1 regardless of the difference in the engine speed NE after the fuel cut is requested. it can.

Second Embodiment
Next, a second embodiment of the engine rotation stop position control device according to the present invention will be described in detail with reference to the drawings.

  In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described.

  This embodiment differs from the first embodiment in terms of the contents of engine rotation stop position control. FIG. 7 is a flowchart showing the contents of the rotation stop position control. In the flowchart of FIG. 7, the contents of Step 100 to Step 140 are the same as those of the flowchart of FIG. 4, and the contents of Step 210 to Step 370 are different from the flowchart of FIG. This control means the operation of the engine rotation stop position control device in this embodiment.

  When the processing shifts to this routine, the processing of step 100 to step 140 is executed as in the first embodiment, and then in step 210, the ECU 50 takes in the engine rotational speed NE based on the detected value of the rotational speed sensor 45.

  Next, at step 220, the ECU 50 obtains a difference between the taken-in engine rotational speed NE and a reference rotational speed NEcf for fuel cut as a rotational speed difference ΔNEcf before fuel cut.

  Next, at step 230, the ECU 50 determines whether or not the rotational speed difference ΔNEcf is greater than a predetermined first reference value A1. If this determination result is affirmative, the ECU 50 proceeds to step 250, assuming that the actual engine speed NE is higher than the predetermined target speed range. Here, the predetermined target rotational speed range is an engine rotational speed NE that is optimum for starting a fuel cut in order to stop the crankshaft 3 at a predetermined rotational position (predetermined crank angle). For example, a rotational speed in the range of “1000 to 1010 (rpm)” can be applied.

  In step 250, the ECU 50 obtains an ignition timing correction value Δaop corresponding to the rotational speed difference ΔNEcf. The ECU 50 can obtain the ignition timing correction value Δaop corresponding to the rotational speed difference ΔNEcf by referring to a map as shown in FIG. 8, for example. When the routine proceeds from step 230 to step 250, the rotational speed difference ΔNEcf becomes a positive value, so that the ignition timing correction value Δaop is determined as a negative amount from the map in FIG.

  On the other hand, if the determination result in step 230 is negative, the ECU 50 proceeds to step 240 and determines whether or not the rotational speed difference ΔNEcf is smaller than a predetermined second reference value −B1 that is a negative value. to decide. If the determination result is affirmative, the ECU 50 proceeds to step 250, assuming that the actual engine speed NE is lower than the predetermined target speed range.

  In step 250, the ECU 50 obtains an ignition timing correction value Δaop corresponding to the rotational speed difference ΔNEcf. The ECU 50 can obtain the ignition timing correction value Δaop corresponding to the rotational speed difference ΔNEcf by referring to a map as shown in FIG. When the routine proceeds from step 240 to step 250, the rotational speed difference ΔNEcf becomes a negative value, so that the ignition timing correction value Δaop is determined as a positive value from the map of FIG.

  Next, at step 260, the ECU 50 obtains the final ignition timing AOP by adding the ignition timing correction value Δaop to the standard ignition timing aop. Here, when the ignition timing correction value Δaop is a positive advance amount, the final ignition timing AOP is obtained as an ignition timing that is advanced from the standard ignition timing aop. On the other hand, when the ignition timing correction value Δaop is a negative retardation amount, the final ignition timing AOP is obtained as an ignition timing that is retarded from the standard ignition timing aop.

  Thereafter, in step 270, the ECU 50 determines whether or not it is the first compression stroke after the fuel cut request. That is, the ECU 50 determines whether or not one cylinder 2 that is first after the fuel cut request enters the compression stroke. When one cylinder 2 enters the compression stroke, another one cylinder 2 enters the intake stroke. Therefore, the determination in this step 270 is that the other one cylinder 2 enters the intake stroke first after the fuel cut request. It will be judged whether or not. If this determination result is affirmative, the ECU 50 proceeds to step 280.

  In step 280, the ECU 50 controls the ignition timing based on the final ignition timing AOP. That is, the ECU 50 controls the spark plug 33 via the ignition coil 34 based on the final ignition timing AOP. Here, the ignition timing is advanced or retarded according to the rotational speed difference ΔNEcf before the fuel cut. Thereafter, the ECU 50 returns the process to step 100.

  On the other hand, if the determination result of step 270 is negative, the ECU 50 proceeds to step 290 and determines whether or not it is the next compression stroke after the fuel cut request. That is, the ECU 50 determines whether or not the next one cylinder 2 enters the compression stroke after the fuel cut request. When one cylinder 2 enters the compression stroke, another one cylinder 2 enters the intake stroke. Therefore, the determination at this step 290 is that the next one cylinder 2 enters the intake stroke after the fuel cut request. It will be judged whether or not. If this determination result is affirmative, the ECU 50 proceeds to step 300.

  In step 300, the ECU 50 requests the electronic throttle device 7 to perform valve opening control in order to open the throttle valve 9. As a result, the throttle valve 9 is actually opened slightly after the valve opening request. In this embodiment, the ECU 50 can open the throttle valve 9 at the idle opening by a predetermined opening (for example, “10 deg”).

  Next, in step 310, the ECU 50 starts fuel cut from one specific cylinder 2 in the intake stroke in response to the fuel cut request, and then sequentially performs fuel cut for other cylinders 2, and the processing is performed in step 100. Return to.

  If the determination result in step 290 is negative, the ECU 50 moves the process to step 310, starts fuel cut from one specific cylinder 2 in the intake stroke, and then sequentially cuts fuel for other cylinders 2 in turn. And the process returns to step 100.

  On the other hand, if the determination result in step 240 is negative, the ECU 50 proceeds to step 320 assuming that the actual engine speed NE is within the predetermined target rotation speed range, and sets the ignition timing correction value Δaop to “ Set to “0”.

  Next, at step 330, the ECU 50 obtains the final ignition timing AOP by adding the ignition timing correction value Δaop to the standard ignition timing aop. Here, since the ignition timing correction value Δaop is “0”, the final ignition timing AOP is obtained as it is as the standard ignition timing aop.

  Thereafter, in step 340, the ECU 50 determines whether or not it is the first compression stroke after the fuel cut request. That is, the ECU 50 determines whether or not one cylinder 2 that is first after the fuel cut request enters the compression stroke. When one cylinder 2 enters the compression stroke, another cylinder 2 enters the intake stroke. Therefore, the determination in this step 340 is that the other cylinder 2 enters the intake stroke first after the fuel cut request. It will be judged whether or not. If this determination result is affirmative, the ECU 50 proceeds to step 350.

  In step 350, the ECU 50 controls the ignition timing based on the final ignition timing AOP, as in step 280. Here, the ignition timing is controlled based on the standard ignition timing aop.

  Next, in step 360, the ECU 50 requests the electronic throttle device 7 to perform valve opening control in order to open the throttle valve 9, as in step 300. As a result, the throttle valve 9 is actually opened slightly after the request for valve opening control.

  Next, in step 370, the ECU 50 starts fuel cut from one specific cylinder 2 in the intake stroke in response to the fuel cut request, and then sequentially performs fuel cut for other cylinders 2 in the same manner as in step 310. Then, the process returns to step 100.

  On the other hand, if the determination result in step 340 is negative, the ECU 50 proceeds to step 370, starts fuel cut from one specific cylinder 2 in the intake stroke in response to the fuel cut request, and then sequentially changes to the other The fuel cut is executed for the cylinder 2 and the process returns to step 100.

  According to the engine rotation stop position control apparatus in this embodiment described above, the same operational effects as in the first embodiment can be obtained. That is, when the engine 1 is stopped, the fuel cut is started when the crank angle is within the predetermined crank angle range CA1 at the time of the request, and the fuel cut is started at the next intake stroke for the specific one cylinder 2. The On the other hand, when the crank angle is not within the predetermined crank angle range CA1 at the time of the request, the fuel cut is started after waiting for the next intake stroke for one specific cylinder 2. . Therefore, even if the request timing of the fuel cut is delayed and a request is made just before the intake stroke, the fuel cut is always started in the intake stroke of one specific cylinder 2, so that the crankshaft 3 always has a predetermined crank angle. Stop at. For this reason, when the engine 1 is stopped, the crankshaft 3 can be stably stopped at a predetermined crank angle suitable for restarting the engine 1.

  In this embodiment, after the fuel cut request is made, the ECU 50 first compresses one cylinder 2 after the fuel cut request when the engine speed NE is within a predetermined target rotational speed range. When entering (when another cylinder 2 first enters the intake stroke), the ignition timing is controlled to the standard ignition timing aop, and the valve opening control is requested to the electronic throttle device 7, and the first The fuel cut is started when the compression stroke is entered (when the intake stroke of another cylinder 2 is entered). Therefore, in this embodiment, even if the timing of the fuel cut request changes from time to time, the fuel cut and the valve opening control of the electronic throttle device 7 are performed in a constant relationship in terms of timing, corresponding to the stop of the engine 1 The pressure state in one specific cylinder 2 is always the same. Also in this sense, when the engine 1 is stopped, the crankshaft 3 can be stably stopped at a predetermined crank angle suitable for restarting the engine 1.

  Further, in this embodiment, after the fuel cut request is made, the ECU 50 is first after the fuel cut request when the engine speed NE is not within the predetermined target rotation speed range optimal for the execution of the fuel cut. When one cylinder 2 first enters the compression stroke (when another one cylinder 2 first enters the intake stroke), the ignition timing is advanced or retarded to adjust the engine speed NE. Thereafter, the ECU 50 requests the electronic throttle device 7 to perform valve opening control when one cylinder 2 after the fuel cut request next enters the compression stroke (when another cylinder 2 next enters the intake stroke). In addition, the fuel cut is started in the compression stroke (intake stroke of another cylinder 2). That is, the ECU 50 determines the ignition timing by the spark plug 33 until the fuel cut is started when the detected engine rotational speed NE is not within the predetermined target rotational speed range after the fuel cut is requested. It is designed to control change. Therefore, when the detected engine speed NE is not within the predetermined target speed range when the fuel cut is requested, the ignition device (ignition plug 33 and ignition coil until the fuel cut is started). The ignition timing according to 34) is changed and controlled, and the engine speed NE is brought close to a predetermined target speed that is optimal for starting fuel cut. Therefore, when the engine 1 is stopped, the crankshaft 3 can be accurately stopped at a predetermined crank angle suitable for restarting the engine 1 regardless of the difference in the engine speed NE after the fuel cut request.

  Here, an example of the rotation stop position control will be described with reference to FIG. FIG. 9 shows (a) an operation stroke (intake stroke, compression stroke, expansion stroke, exhaust stroke) of No. 1 cylinder # 1 to # 4 cylinder # 4, (b) crank angle, (c) fuel cut signal (F / (C signal), (d) throttle opening degree TA, (e) ignition timing, and (f) engine speed NE behavior are shown in a time chart. In FIG. 9, a thick line indicates a case where the engine speed NE is not a predetermined target speed (“600 (rpm)” in this embodiment) at the time of fuel cut request, and a thick broken line indicates the fuel The case where the engine rotational speed NE is a predetermined target rotational speed at the time of a cut request is shown. First, when the engine rotational speed NE (idle rotational speed) is a predetermined target rotational speed (600 (rpm)), as shown in FIGS. When a fuel cut request (F / C request) is input at time t1 after fuel injection in the intake stroke, the fuel cut can actually be started thereafter as shown by the thick broken lines in FIGS. 9 (c) and 9 (d). Is the time t2 when the third cylinder # 3 enters the intake stroke (the first cylinder # 1 enters the compression stroke). The electronic throttle device 7 is requested to open the valve at the same time t2, and the throttle valve 9 is actually opened at a slightly delayed time t3. Further, as shown in FIG. 9E, the ignition timing at this time does not change before and after the fuel cut request is input, and is constant at the standard ignition timing aop. As described above, the timing at which the fuel cut is actually started after the fuel cut request and the timing at which the throttle valve 9 is opened from the idle opening are enclosed by the broken-line square S1 in FIGS. 9 (c) and 9 (d). So you will always keep a certain relationship. As a result, as shown by a thick broken line in FIG. 9F, the decreasing gradient (decreasing rate) of the engine speed NE from time t6 is always constant without variation. For this reason, the rotation stop position (stop crank angle) of the engine 1 and the pressure state in the cylinder 2 corresponding thereto are constant without variation, and the stop crank angle can be controlled to a crank angle range suitable for starting the engine 1. it can.

  On the other hand, when the engine rotational speed NE (idle rotational speed) is higher than the predetermined target rotational speed, as shown in FIGS. 9A and 9C, the fuel cut request (F / C request) at time t1. 9 (c), (d), the fuel cut can actually be started after that, because the fourth cylinder # 4 enters the intake stroke (the third cylinder # 3 is compressed) Enter the process) Time t4. Similarly, the electronic throttle device 7 is requested to open the valve at time t4, and the throttle valve 9 is actually opened at time t5 which is a little later. The ignition timing at this time is retarded from the standard ignition timing aop at time t2 when the first cylinder # 1 first enters the compression stroke after the fuel cut request is made. As described above, the timing at which the fuel cut is actually started after the fuel cut request and the timing at which the throttle valve 9 is opened from the idle opening are enclosed by the broken-line square S2 in FIGS. 9 (c) and 9 (d). So you will always keep a certain relationship. As a result, as indicated by a thick line in FIG. 9 (f), the decrease gradient (decrease rate) of the engine speed NE from time t6 approaches the target state indicated by the thick broken line. Therefore, the rotation stop position (stop crank angle) of the engine 1 and the corresponding pressure state in the cylinder 2 can be brought close to the target state, and the stop crank angle is brought close to a crank angle range suitable for starting the engine 1. be able to.

  In addition, in this embodiment, after the fuel cut is requested, the ECU 50 requests the fuel cut if the detected engine rotational speed NE is not within a predetermined target rotational speed range optimal for the fuel cut. The time when one of the later cylinders 2 first enters the compression stroke (when another one of the cylinders 2 first enters the intake stroke) passes, and when one of the other cylinders 2 enters the compression stroke next (the other one) (When one cylinder 2 enters the intake stroke next time), the electronic throttle device 7 is requested to perform valve opening control, and the fuel cut is started in the compression stroke (intake stroke of another cylinder 2). It has become. That is, the ECU 50 controls the injector 32 so as to delay the start of the fuel cut when the detected engine rotational speed NE is not within the predetermined target rotational speed range after the fuel cut is requested. Yes. Therefore, if the actual engine speed NE is not within the predetermined target speed range after the fuel cut is requested, the fuel cut is not started during that time. For this reason, the actual engine rotational speed NE can be brought close to the target rotational speed range optimum for the start of fuel cut.

  Note that the present invention is not limited to the above-described embodiments, and a part of the configuration can be changed as appropriate without departing from the spirit of the invention.

  (1) In each of the above embodiments, the fuel is injected and supplied by the injector 32 during the intake stroke, and the fuel cut is started when the intake stroke is reached. However, depending on the engine, the stroke for injecting fuel is different, for example, Fuel may be supplied by the fuel supply means in the exhaust stroke, and the fuel cut may be started when the exhaust stroke is reached.

  (2) In each of the above embodiments, the present invention is embodied in the engine 1 having the four cylinders 2. However, the number of cylinders of the engine is not limited to four, and may be embodied in an engine having any possible number of cylinders. Can do.

  (3) The engine system in each of the above embodiments may be mounted on a vehicle using only the engine 1 as a driving source, or mounted on a hybrid vehicle using both an engine and a motor as a driving source. It may be.

  The present invention can be used for an idle stop system employed in an engine.

1 Engine 2 Cylinder 3 Crankshaft (Rotating shaft)
28 Timing rotor 32 Injector (fuel supply means)
33 Spark plug 34 Ignition coil (33 and 34 constitute ignition means)
45 Rotational speed sensor (28 and 45 constitute rotation detection means)
50 ECU (control means, ignition timing control means)

Claims (4)

An engine rotation stop position control device for controlling an engine rotation shaft to stop at a predetermined rotation position,
The engine is a reciprocating engine including a plurality of cylinders, and is configured to rotate the rotating shaft by burning the fuel supplied by the fuel supply means in each cylinder;
The fuel supply means is configured to supply fuel to each cylinder;
Rotation detection means for detecting the rotation position and rotation speed of the rotation shaft;
In order to stop the rotation shaft at the predetermined rotational position, the engine is provided with a control means for controlling the fuel supply means so that the fuel supply is sequentially stopped from a specific cylinder for each cylinder. In the position control device,
The control means requests the fuel supply to be stopped when stopping the rotation shaft at the predetermined rotation position, and at the time of the request, the rotation position detected by the rotation detection means is related to the specific cylinder. When the fuel supply is stopped within a predetermined range that allows the fuel supply to be stopped at a specific stroke next time, the fuel supply is started so as to start the fuel supply stop at the specific stroke next time for the specific cylinder. The fuel supply means is controlled so as to delay the start of the stop of the fuel supply until a specific stroke one after another for the specific cylinder when the detected rotational position is not within the predetermined range. An engine rotation stop position control device characterized by controlling the engine.   2. The engine rotation stop position control device according to claim 1, wherein the specific stroke is an intake stroke. Ignition means for igniting the fuel supplied to each cylinder;
Ignition timing control means for controlling the ignition timing by the ignition means,
The ignition timing control means, when the control means requests the fuel supply to stop, if the rotation speed detected by the rotation detection means does not reach a predetermined target rotation speed, the ignition timing control means The engine rotation according to claim 1 or 2, wherein the ignition timing by the ignition means is changed and controlled in order to adjust the rotation speed of the rotating shaft until the supply stop is started. Stop position control device.   When the rotation speed detected by the rotation detection means does not reach the predetermined target rotation speed after requesting the fuel supply stop, the control means delays the start of the fuel supply stop. The engine rotation stop position control device according to any one of claims 1 to 3, wherein the fuel supply means is controlled.

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