JP2016113905A - Rotation stop position control device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start control for stopping a rotating shaft at a prescribed rotation position from a state that an engine rotation speed is comparatively high, in stopping an engine.SOLUTION: An engine 1 is a reciprocal engine rotating a shaft 3 by burning a fuel supplied from each injector 32. A throttle device 7 is used to regulate rotation of the shaft 3 in stopping the engine. An ECU 50 controls the throttle device 7 so that a rotation speed detected by a rotation speed sensor 45 reaches a prescribed target rotation speed from fuel-cut by each injector 32 to stop the shaft 3 at a prescribed crank position. The ECU 50 measures a lapse time necessary for rotation by a prescribed angle from a corresponding specific crank position after expansion BDC in one cylinder 2 of which the fuel supply is finished last among the plurality of cylinders 2, as a rotation speed detected after fuel-cut, and calculates and takes the rotation speed from the lapse time.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 engine starter 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 starting. It has become. That is, when the engine is stopped, fuel is injected into the cylinder in the expansion stroke and ignited and burned to restart the engine with the power of the engine itself without borrowing the power of the starter motor. It is like that. Specifically, in the process in which the engine rotation speed decreases after the fuel supply to the engine is stopped, the engine rotation speed (top dead center rotation speed) when each cylinder passes the compression top dead center is measured by the rotation speed sensor. The throttle valve opening is electrically controlled so that its top dead center rotational speed is within a predetermined rotational speed range correlated with the piston position after the engine is stopped.

JP 2005-155548 A

  However, in the device described in Patent Document 1, the opening degree of the throttle valve is controlled so that the top dead center rotational speed is within a predetermined rotational speed range correlated with the piston position after the engine is stopped. The control could not be performed from the stage where the top dead center rotation speed was relatively high. Further, by controlling the opening of the throttle valve, the load applied to the engine, that is, the deceleration torque applied to the crankshaft is not so large. For this reason, even if the throttle valve opening is controlled when the top dead center rotational speed is low, the time until the rotation of the crankshaft stops is short, and sufficient deceleration torque cannot be applied to the crankshaft. The engine rotation stop position could not be suitably controlled within the crank angle range suitable for starting.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to start control for stopping a rotating shaft at a predetermined rotational position from a state where the rotational speed of the engine is relatively high when the engine is stopped. An object of the present invention is to provide an engine rotation stop position control device that makes it possible.

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, wherein the engine has a combustion chamber disposed therein. A reciprocating engine including a plurality of cylinders having a configuration in which a rotation shaft is rotated by burning fuel supplied from a fuel supply unit in a combustion chamber; A rotation adjusting means for adjusting the rotation of the rotating shaft by applying a load to the engine, a rotating speed detecting means for detecting the rotating speed of the rotating shaft, and the rotating shaft In order to stop the engine at a predetermined rotation position, the rotation speed detected by the rotation speed detection means after the fuel supply means stops supplying fuel to each cylinder becomes the predetermined target rotation speed. In the engine rotation stop position control device having the control means for controlling the rotation adjusting means as described above, the control means is detected by the rotation speed detecting means after the fuel supply means stops the fuel supply to each cylinder. Measuring the elapsed time taken to rotate a predetermined angle from a specific rotational position of the corresponding rotating shaft after expansion bottom dead center in one cylinder that finishes supplying fuel last among a plurality of cylinders, The purpose is to calculate the rotational speed of the rotary shaft from the elapsed time.

  According to the configuration of the invention described above, when the engine is stopped, the control unit adjusts the rotation so that the rotation speed detected by the rotation speed detection unit becomes the predetermined target rotation speed after stopping the fuel supply by the fuel supply unit. Control means. As a result, the rotation of the rotating shaft starts to stop, a load is applied to the engine, a deceleration torque is applied to the rotating shaft, and the rotating shaft stops at a predetermined rotational position. Here, the control means is one cylinder that finishes the fuel supply last among a plurality of cylinders as the rotational speed detected by the rotational speed detection means after stopping the fuel supply to each cylinder by the fuel supply means. Measure the elapsed time taken to rotate a predetermined angle from the specific rotational position of the corresponding rotating shaft after the expansion bottom dead center in, and calculate the rotational speed of the rotating shaft from the elapsed time. The rotation speed of a specific rotation position corresponding to the expansion bottom dead center in one cylinder that finishes the fuel supply last is the rotation angle at which the rotation shaft rolls before the rotation stops and the position at which the rotation of the rotation shaft stops. And is related to Therefore, even when the rotational speed of the rotational shaft is relatively high, the rotational adjustment means can be controlled so that the rotational speed becomes the predetermined target rotational speed by taking in the rotational speed at the specific rotational position. Become.

  In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the invention, one cylinder that ends the fuel supply is fixed to a specific cylinder among the plurality of cylinders. The purpose is that.

  According to the configuration of the invention, in addition to the operation of the invention according to claim 1, the one cylinder that finishes the fuel supply last is fixed to the specific cylinder, so that the rotational position for stopping the rotation of the rotary shaft is It is always adjusted to the same position.

  To achieve the above object, according to a third aspect of the present invention, in the first or second aspect of the invention, the control means detects the rotation speed detecting means after stopping the fuel supply by the fuel supply means. The purpose is to calculate a deviation of the rotation speed to a predetermined target rotation speed and to control the rotation adjusting means in accordance with the deviation.

  According to the configuration of the invention, in addition to the operation of the invention according to claim 1 or 2, the rotation adjusting means is controlled according to the deviation of the rotation speed from the predetermined target rotation speed. There is no need to control.

  In order to achieve the above object, a fourth aspect of the invention is the invention according to any one of the first to third aspects, wherein an in-cylinder pressure detecting means for detecting a pressure in each combustion chamber, and a cylinder And a deceleration torque estimating means for estimating a deceleration torque applied to the rotating shaft based on a value detected by the internal pressure detecting means, and the control means corrects the control of the rotation adjusting means according to the estimated magnitude of the deceleration torque. The purpose is to do.

  According to the configuration of the invention, in addition to the operation of the invention according to any one of claims 1 to 3, the pressure in the combustion chamber of each cylinder has a correlation with the deceleration torque of the rotating shaft. Therefore, the deceleration torque estimating means estimates the deceleration torque based on the pressure in the combustion chamber actually detected by the in-cylinder pressure detecting means, and the control means rotates according to the estimated magnitude of the deceleration torque. Since the control of the adjusting means is corrected, the rotation speed of the rotating shaft is adjusted more appropriately and accurately to a predetermined target rotation speed.

  In order to achieve the above object, according to a fifth aspect of the invention, in the invention of the fourth aspect, the control means first supplies fuel by the fuel supply means according to the estimated magnitude of the deceleration torque. The purpose is to change the cylinder to be stopped.

  According to the configuration of the invention, in addition to the operation of the invention according to claim 4, the cylinder that first stops the fuel supply by the fuel supply means is changed according to the estimated magnitude of the deceleration torque. The amount of deceleration torque of the rotating shaft to be adjusted by the rotation adjusting means is reduced, and the adjustment time is shortened.

  In order to achieve the above object, the invention according to claim 6 is the invention according to claim 5, wherein the control means obtains the target rotational speed based on the estimated deceleration torque.

  According to the configuration of the above invention, in addition to the operation of the invention according to the fifth aspect, the target rotational speed at which the rotational speed is to be adjusted is obtained based on the estimated deceleration torque. There is no need to control.

  According to the first aspect of the present invention, when the engine is stopped, the control for stopping the rotating shaft at a predetermined rotational position can be started from a state where the rotational speed of the engine is relatively high.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the specific cylinder corresponding to the predetermined rotational position to be stopped can be stopped in a state suitable for starting the engine.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the rotation adjusting means is not driven wastefully, the use time can be shortened, and the power consumption can be reduced. Can be suppressed.

  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, the rotation of the rotating shaft can be stopped at a predetermined rotational position with high accuracy.

  According to the fifth aspect of the invention, in addition to the effect of the fourth aspect of the invention, the rotation of the rotary shaft can be quickly stopped at a predetermined rotational position only by controlling the rotation adjusting means.

  According to the invention described in claim 6, in addition to the effect of the invention described in claim 5, the rotation adjusting means is not driven wastefully, the use time can be shortened, and the power consumption is further suppressed. be able to.

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 graph which shows the relationship between the engine speed at the time of combustion torque generation, a stop cylinder, and a total crank angle concerning 1st Embodiment. The graph which shows the relationship between the engine speed of the specific crank position corresponding to after expansion BDC in the last injection cylinder, a stop cylinder, and a total crank angle according to the first embodiment. The time chart which shows the behavior of (a) engine rotational speed, (b) fuel injection of each cylinder, and (c) crank angle when an engine stops from the time of idle driving 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. Map data referred to in order to obtain a rotation speed threshold according to the deceleration torque deviation according to the second embodiment. The flowchart which shows the content of 3rd Embodiment and the rotation stop position control of an engine.

<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 reciprocating type four-cycle engine, and includes eight 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 that ignites a 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 elapses. 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. As described above, the combustion of the combustible air-fuel mixture in each combustion chamber 15 causes each piston 13 to move up and down, and a series of operation strokes proceeds to rotate the crankshaft 3, thereby obtaining power 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. This in-cylinder pressure sensor 42 corresponds to the in-cylinder pressure detecting means of the present invention.

  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 a 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 rotational speed sensor 45 and the timing rotor 28 correspond to the rotational speed 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 speed detecting 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 intake air amount in the intake passage 4. In this embodiment, the electronic throttle device 7 adjusts the rotation of the crankshaft 3 by applying a load to the engine 1. It also functions as the rotation adjusting means of the present invention that operates in the same manner. That is, when a fuel cut is performed on the engine 1 to stop the engine 1, the electronic throttle device 7 is operated to open the throttle valve 9, thereby applying a load to the engine 1. The engine speed NE is adjusted by changing the deceleration torque of the engine.

  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 an automatic stop condition for the engine 1 is established in a predetermined cylinder 2. The ECU 50 determines, for example, that the engine rotation speed NE is reduced to a predetermined reference value that should be fuel cut as an automatic stop condition.

  If the determination result in step 100 is affirmative, in step 110, the ECU 50 executes fuel cut. That is, the ECU 50 stops the engine 1 by sequentially stopping the fuel supply by the injectors 32 for each cylinder 2.

  Next, at step 120, the ECU 50 opens and controls the throttle valve 9 to a predetermined opening. That is, the ECU 50 opens the throttle valve 9 that should be normally closed when the engine 1 is stopped to a predetermined opening by controlling the electronic throttle device 7. Thereby, in the process of stopping the engine 1, the throttle opening degree TA is corrected so that the deceleration torque can be controlled.

Next, at step 130, the ECU 50 takes in the engine rotational speed NE at a specific crank position corresponding to after the expansion BDC in the final injection cylinder 2. That is, the ECU 50 stops the fuel supply lastly among the eight cylinders 2 as the engine rotational speed NE detected by the rotational speed sensor 45 after stopping the fuel supply to each cylinder 2 by each injector 32. Rotational speed when a specific crank position (that is, a specific tooth 28a on the timing rotor 28) corresponding to the expansion BDC in the cylinder (final injection cylinder) 2 passes one adjacent point (that is, the rotational speed sensor 45). Calculate and import. Here, the specific crank position is set to “ABDC 3 ° C. A (= ATDC 183 ° C. A)” in this embodiment. The ECU 50 measures the elapsed time from the specific crank position until the crankshaft 3 is rotated by a predetermined angle every time the crankshaft 3 rotates twice (720 ° A rotation), and the engine speed NE is calculated from the elapsed time. Is calculated and captured. In this embodiment, the final injection cylinder is fixed to one specific cylinder 2 among the eight cylinders 2.

  Next, at step 140, the ECU 50 determines whether or not the engine speed NE is within a predetermined range. That is, the ECU 50 determines whether or not the engine rotational speed NE that is captured as described above is at a predetermined target rotational speed (a rotational speed within a predetermined range). As the rotation speed within the predetermined range, for example, a rotation speed within a range of about “990 to 1010 (rpm)” can be assumed. The rotation speed within this predetermined range is a rotation speed at which the crankshaft 3 can be predicted to be stopped at a predetermined crank position (crank angle), which is a predetermined rotation position, that is, a specific cylinder 2 can be stopped at the initial stage of the expansion stroke. is there. Since the specific cylinder 2 can be stopped at the initial stage of the expansion stroke, when the engine 1 is restarted, the engine 1 can be started by itself by supplying fuel to the cylinder 2 and burning it first. .

  If the determination result in step 140 is affirmative, the rotation of the crankshaft 3 is stopped in a state where the specific cylinder 2 is in the initial stage of the expansion stroke, so the ECU 50 proceeds to step 180, The rotation stop position (stop crank position) of the crankshaft 3 is positively detected based on the detection value of the rotation speed sensor 45, and the subsequent processing is terminated.

  On the other hand, if the determination result in step 140 is negative, the ECU 50 proceeds to step 150 and calculates a rotational speed deviation ΔNE of the engine rotational speed NE with respect to the target rotational speed (rotational speed within a predetermined range).

  Next, at step 160, the ECU 50 calculates an adjustment opening degree ΔTA1 related to the throttle valve 9 from the rotational speed deviation ΔNE. The ECU 50 can calculate the adjustment opening ΔTA1 by referring to predetermined map data, for example.

  Next, at step 170, the ECU 50 controls to change the opening degree of the throttle valve 9 by the adjustment opening degree ΔTA1. That is, the throttle valve 9 opened to a predetermined opening is changed by the adjustment opening ΔTA1 by further controlling the electronic throttle device 7. As a result, the load applied to the engine 1 is changed to further adjust the deceleration torque of the crankshaft 3, and the engine rotational speed NE is adjusted within a predetermined range.

  That is, in steps 150 to 170, the ECU 50 corrects the control of the electronic throttle device 7 according to the magnitude of the rotational speed deviation ΔNE.

  Thereafter, the ECU 50 shifts the process to step 180, positively detects the rotation stop position (stop crank position) of the crankshaft 3 based on the detected value of the rotation speed sensor 45, and ends the subsequent process.

  According to the engine rotation stop position control apparatus in this embodiment described above, when the engine 1 is stopped, the ECU 50 stops the fuel supply by the injector 32 and then detects the engine rotation speed NE detected by the rotation speed sensor 45. The electronic throttle device 7 is controlled so that becomes a predetermined target rotational speed (rotational speed within a predetermined range). As a result, the rotation of the crankshaft 3 starts to stop, a load is applied to the engine 1 and a deceleration torque is applied to the crankshaft 3, and the rotation of the crankshaft 3 is performed at a predetermined crank position, that is, a certain cylinder 2 It stops at a position that is the initial stage of the expansion stroke.

  Here, the ECU 50 ends the fuel supply lastly among the eight cylinders 2 as the engine rotational speed NE detected by the rotational speed sensor 45 after the fuel supply to each cylinder 2 by the injector 32 is stopped. The elapsed time taken to rotate a predetermined angle from the corresponding specific crank position after the expansion BDC in one cylinder (final injection cylinder) 2 is measured, and the engine speed NE is calculated and taken from the elapsed time. That is, the rotational speed at which one tooth 28 a on the timing rotor 28 corresponding to a specific crank position of the crankshaft 3 crosses the rotational speed sensor 45 is captured.

  By the way, the engine rotational speed NE when the fuel is supplied to each cylinder 2 by each injector 32 is not related to the crank position (stop crank position) when the rotation of the crankshaft 3 is stopped. That is, the engine rotational speed NE when the combustion torque is generated in the engine 1 is not related to the stop crank position (see FIG. 5). However, the applicant of the present application has determined that the rotation speed at a specific crank position corresponding to the expansion BDC after the expansion BDC in the final injection cylinder 2 is the rotation angle at which the crankshaft 3 rolls before the rotation stops and the stop crank position of the crankshaft 3. (See FIG. 6). FIG. 5 is a graph showing the relationship between the engine rotational speed NE, the stopped cylinder, and the total crank angle when fuel is supplied to the engine 1 (when combustion torque is generated). FIG. 6 is a graph showing the relationship between the engine rotational speed NE at a specific crank position corresponding to after the expansion BDC in the final injection cylinder 2, the stopped cylinder and the total crank angle. The “stop cylinder” means a specific cylinder 2 that can be stopped at the initial stage of the expansion stroke when the rotation of the crankshaft 3 is stopped. According to FIG. 6, it can be seen that the stop cylinder can be obtained according to the engine speed NE.

  FIG. 7 is a time chart showing the behavior of (a) engine rotational speed NE, (b) fuel injection of each cylinder, and (c) crank angle when the engine is stopped from idling. As can be seen from FIG. 7, when the final injection is completed at time t1, expansion BDC occurs in a specific cylinder at time t2, and the engine rotation speed NE starts to decrease. Thereafter, the rotation of the crankshaft is stopped at time t3, but between times t2 and t3, the engine rotational speed NE continues to decrease, and the crank angle changes three and a half times with “0 to 720 ° C.” as one time. . In other words, the crankshaft rotates by 7 turns due to inertia. Since no combustion torque is generated in the engine between times t2 and t3, the rotation of the crankshaft during this time is an inertia rotation (rolling) due to the combustion torque generated in the cylinder that has finished the final injection. The total crank angle TCA1 from the final injection to the rotation stop at this time and the total crank angle TCA2 after the subsequent expansion BDC are values unique to each engine, and are referred to as “rolling angle θRL”.

  Accordingly, even when the engine rotational speed NE is relatively high, the engine rotational speed NE is obtained as a predetermined target rotational speed (a rotational speed within a predetermined range) by taking the rotational speed at the specific crank position as the engine rotational speed NE. It is possible to control the electronic throttle device 7 so that Therefore, when the engine 1 is stopped, the rotation stop position control for stopping the rotation of the crankshaft 3 at a predetermined crank position (stop crank position) can be started from a state where the engine rotation speed NE is relatively high. As a result, the stop crank position can be suitably controlled to a crank position suitable for starting the engine 1.

  In this embodiment, since the final injection cylinder 2 is fixed to a specific cylinder 2 among the eight cylinders 2, the stop crank position of the crankshaft 3 is always set to the same crank position. For this reason, the specific cylinder 2 corresponding to the stop crank position can be stopped in a state suitable for starting the engine 1, that is, in the initial stage of the expansion stroke.

  In this embodiment, since the electronic throttle device 7 is controlled according to the rotational speed deviation ΔNE with respect to the predetermined target rotational speed (the rotational speed within a predetermined range) of the engine rotational speed NE, the electronic throttle device 7 is controlled more than necessary. There is no need to do. For this reason, the electronic throttle device 7 is not driven unnecessarily, the usage time thereof can be shortened, and the power consumption can be suppressed.

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. In this embodiment, the ECU 50 corresponds to a deceleration torque estimating means in addition to the control means. FIG. 8 is a flowchart showing the contents of the rotation stop position control. 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 200, the ECU 50 estimates a deceleration torque TR0 determined by the in-cylinder pressure PS detected by the in-cylinder pressure sensor 42 and the crank mechanism (the crankshaft 3 of the 8-cylinder engine). . For example, the ECU 50 can estimate the deceleration torque TR0 by referring to predetermined map data.

  Next, at step 210, the ECU 50 calculates a deceleration torque deviation ΔTR of the estimated deceleration torque TR0 with respect to a predetermined reference value.

  Next, at step 220, the ECU 50 determines the engine speed threshold value (rotation speed threshold value) NES and the cylinder to which the fuel cut should be started first among the eight cylinders 2 in accordance with the calculated deceleration torque deviation ΔTR (step 220). Fuel cut start cylinder) SFC is obtained. Here, the ECU 50 can obtain the rotational speed threshold value NES corresponding to the deceleration torque deviation ΔTR, for example, by referring to map data as shown in FIG. Further, the ECU 50 can obtain the fuel cut start cylinder SFC according to the deceleration torque deviation ΔTR, for example, by referring to predetermined map data.

  Next, at step 230, the ECU 50 first starts fuel cut with the obtained fuel cut start cylinder SFC, and then sequentially performs fuel cut with the remaining cylinders 2. That is, the fuel supply by each injector 32 is sequentially stopped from the fuel cut start cylinder SFC, and the engine 1 is stopped.

  Next, at step 240, the ECU 50 opens and controls the throttle valve 9 to a predetermined opening. That is, the ECU 50 opens the throttle valve 9 that should be normally closed when the engine 1 is stopped to a predetermined opening by controlling the electronic throttle device 7. Thereby, in the process of stopping the engine 1, the throttle opening degree TA is corrected so that the deceleration torque can be controlled.

  Next, at step 250, the ECU 50 takes in the engine rotational speed NE at a specific crank position corresponding to after the expansion BDC in the final injection cylinder 2. The details of the processing contents in this step 250 are the same as those in step 130 of FIG.

  Next, in step 260, the ECU 50 determines whether or not the engine rotational speed NE is within the rotational speed threshold NES. That is, the ECU 50 determines whether or not the engine rotational speed NE calculated as described above is at a predetermined target rotational speed (rotational speed within the rotational speed threshold NES). The rotational speed threshold value NES reflects the deceleration torque TR0 actually applied to the crankshaft 3.

  If the determination result in step 260 is affirmative, the ECU 50 proceeds to step 300 because the rotation of the crankshaft 3 stops in a state where the specific cylinder 2 is in the initial stage of the expansion stroke. The rotation stop position (stop crank position) of the crankshaft 3 is positively detected based on the detection value of the rotation speed sensor 45, and the subsequent processing is terminated.

  On the other hand, if the determination result in step 260 is negative, the ECU 50 proceeds to step 270 and calculates the rotational speed deviation ΔNE of the engine rotational speed NE with respect to the target rotational speed (the rotational speed within the rotational speed threshold NES). To do.

  Next, in step 280, the ECU 50 calculates an adjustment opening degree ΔTA2 related to the throttle valve 9 from the estimated deceleration torque TR0 and the rotational speed deviation ΔNE. The ECU 50 can calculate the adjustment opening degree ΔTA2 by referring to predetermined map data, for example.

  Next, at step 290, the ECU 50 controls to change the opening degree of the throttle valve 9 by the adjustment opening degree ΔTA2. That is, the throttle valve 9 opened to a predetermined opening is changed by the adjustment opening ΔTA 2 by controlling the electronic throttle device 7. Thus, the load applied to the engine 1 is changed to further adjust the deceleration torque of the crankshaft 3, and the engine rotational speed NE is adjusted to the rotational speed within the rotational speed threshold value NES.

  That is, in steps 270 to 290, the ECU 50 corrects the control of the electronic throttle device 7 according to the estimated deceleration torque TR0 and the magnitude of the rotational speed deviation ΔNE.

  Thereafter, the ECU 50 shifts the process to step 300, positively detects the rotation stop position (stop crank position) of the crankshaft 3 based on the detected value of the rotation speed sensor 45, and ends the subsequent process.

  According to the engine rotation stop position control apparatus in this embodiment described above, when the engine 1 is stopped, the ECU 50 stops the fuel supply by the injector 32 and then detects the engine rotation speed NE detected by the rotation speed sensor 45. Is controlled to be a predetermined target rotational speed (rotational speed within the rotational speed threshold NES). As a result, the rotation of the crankshaft 3 starts to stop, a load is applied to the engine 1 and a deceleration torque is applied to the crankshaft 3, and the rotation of the crankshaft 3 is performed at a predetermined crank position, that is, a certain cylinder 2 It stops at a position that is the initial stage of the expansion stroke.

  Here, the ECU 50 determines the specific crank position corresponding to after the expansion BDC in the final injection cylinder 2 as the engine rotational speed NE detected by the rotational speed sensor 45 after the fuel supply to each cylinder 2 by the injector 32 is stopped. Is measured from the elapsed time until the engine is rotated by a predetermined angle, and the engine rotational speed NE is calculated from the elapsed time and taken in. That is, the rotational speed at which one tooth 28 a on the timing rotor 28 corresponding to a specific crank position of the crankshaft 3 crosses the rotational speed sensor 45 is captured.

  Therefore, even when the engine speed NE is relatively high, the engine speed NE is acquired as the engine speed NE by taking the rotational speed at the specific crank position as the engine speed NE. It is possible to control the electronic throttle device 7 so as to be (speed). Therefore, when the engine 1 is stopped, the rotation stop position control for stopping the rotation of the crankshaft 3 at a predetermined stop crank position can be started from a state where the engine rotation speed NE is relatively high. As a result, the stop crank position can be suitably controlled to a crank position suitable for starting the engine 1.

  In this embodiment, since the final injection cylinder 2 is fixed to a specific cylinder 2 among the eight cylinders 2, the stop crank position of the crankshaft 3 is always set to the same crank position. Therefore, the predetermined cylinder 2 corresponding to the stop crank position can be stopped in a state suitable for starting the engine 1, that is, in the initial stage of the expansion stroke.

  In this embodiment, the electronic throttle device 7 is controlled according to the rotational speed deviation ΔNE with respect to the predetermined target rotational speed (the rotational speed within the rotational speed threshold value NES) of the engine rotational speed NE. There is no need to control. For this reason, the electronic throttle device 7 is not driven unnecessarily, the usage time thereof can be shortened, and the power consumption can be suppressed.

  In this embodiment, the pressure (in-cylinder pressure PS) in the combustion chamber 15 of each cylinder 2 has a correlation with the deceleration torque of the crankshaft 3. Accordingly, the ECU 50 estimates the deceleration torque based on the in-cylinder pressure PS actually detected by the in-cylinder pressure sensor 42, and corrects the control of the electronic throttle device 7 according to the estimated magnitude of the deceleration torque. Therefore, the engine rotational speed NE is more appropriately set to the predetermined target rotational speed (the rotational speed within the rotational speed threshold value NES) even under the condition that the friction varies depending on the viscosity of the lubricating oil supplied to the crankshaft 3 and the product machine difference. Adjusted precisely. For this reason, the rotation of the crankshaft 3 can be accurately stopped at the predetermined crank position.

  In this embodiment, the ECU 50 changes the fuel cut start cylinder SFC that starts the fuel cut by the injector 32 according to the estimated magnitude of the deceleration torque TR0. The amount of deceleration torque of the shaft 3 is reduced, and the adjustment time is shortened. For this reason, the rotation of the crankshaft 3 can be quickly stopped at a predetermined crank position only by controlling the electronic throttle device 7. Here, depending on the magnitude of the deceleration torque, it is necessary to correct “720 ° C.” at the maximum with the crank position as the crank angle. For this correction, it is necessary to adjust the deceleration torque in a large amount. In this embodiment, since the engine is an 8-cylinder engine, it is only necessary to correct the crank angle by “90 ° C. A” only by changing the fuel cut start cylinder SFC. It is possible to quickly stop at a predetermined crank position.

  In this embodiment, since the target rotational speed (the rotational speed within the rotational speed threshold value NES) for adjusting the engine rotational speed NE is obtained based on the deceleration torque TR0 estimated by the ECU 50, the electronic throttle device 7 is used more than necessary. There is no need to control. For this reason, the electronic throttle device 7 is not driven unnecessarily, the usage time thereof can be shortened, and the power consumption can be further suppressed.

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

  This embodiment differs from the second embodiment in terms of the contents of engine rotation stop position control. FIG. 10 is a flowchart showing the contents of the rotation stop position control. The flowchart of FIG. 10 differs from steps 210, 220, 260, and 270 of the flowchart of FIG. 8 in terms of the contents of steps 215, 225, 265, and 275.

  That is, in step 215, the ECU 50 calculates the rolling angle θRL (total crank angle TCA2 shown in FIG. 7) based on the estimated deceleration torque TR0.

  Next, in step 225, the ECU 50 calculates the fuel cut start cylinder SFC by calculating backward from the calculated rolling angle θRL and the target stop crank position. Here, the target stop crank position means the target crank position when the rotation of the crankshaft 3 is stopped, and means the crank position at which the specific cylinder 2 can be stopped at the initial stage of the expansion stroke. . For example, the ECU 50 can obtain the fuel cut start cylinder SFC according to the rolling angle θRL and the target stop crank position by referring to predetermined map data.

  In step 265, the ECU 50 determines whether or not the engine speed NE is within a predetermined range. That is, the ECU 50 determines whether or not the engine rotational speed NE calculated as described above is at a predetermined target rotational speed.

  Further, in step 275, the ECU 50 calculates a rotational speed deviation ΔNE of the engine rotational speed NE with respect to the target rotational speed (rotational speed within a predetermined range).

  Therefore, this embodiment can basically obtain the same operational effects as those of the second embodiment.

  Note that the present invention is not limited to the above-described embodiments, and can be implemented as follows by appropriately changing a part of the configuration without departing from the spirit of the invention.

  (1) In each of the above embodiments, the rotation adjusting means is constituted by the electronic throttle device 7. However, the present invention is not limited to this, and any other device may be used as long as it can adjust the rotational speed of the engine rotation shaft. You can also. For example, a variable valve timing mechanism (VVT) that can change the opening / closing timing of an intake valve or an exhaust valve, an alternator that can adjust the engine rotation speed by making an electric load variable, or an electric motor is used as the rotation adjusting means. Can do.

  (2) 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)
7 Electronic throttle device (rotational speed adjusting means)
15 Combustion chamber 28 Timing rotor 32 Injector (fuel supply means)
42 In-cylinder pressure sensor (in-cylinder pressure detection means)
45 Rotational speed sensor (28 and 45 constitute rotational speed detection means)
50 ECU (control means, deceleration torque estimation means)

Claims (6)

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 having a combustion chamber, and is configured to rotate the rotating shaft by burning fuel supplied by a fuel supply means in the combustion chamber;
The fuel supply means is configured to supply fuel to each cylinder;
Rotation adjusting means for adjusting the rotation of the rotating shaft by applying a load to the engine;
A rotational speed detecting means for detecting the rotational speed of the rotary shaft;
In order to stop the rotation shaft at the predetermined rotation position, the rotation speed detected by the rotation speed detection means after the fuel supply means stops supplying fuel to the cylinders is a predetermined target rotation speed. In the engine rotation stop position control device comprising the control means for controlling the rotation adjustment means so that
The control means ends the supply of the fuel among the plurality of cylinders as the rotation speed detected by the rotation speed detection means after stopping the fuel supply to the cylinders by the fuel supply means. Measure the elapsed time taken to rotate a predetermined angle from a specific rotational position of the rotating shaft corresponding to after the expansion bottom dead center in one cylinder, and calculate the rotational speed of the rotating shaft from the elapsed time An engine rotation stop position control device.   2. The engine rotation stop position control device according to claim 1, wherein one cylinder that finishes supplying fuel last is fixed to a specific cylinder among the plurality of cylinders.   The control means calculates a deviation of the rotation speed detected by the rotation speed detection means from the predetermined target rotation speed after stopping the fuel supply by the fuel supply means, and adjusts the rotation according to the deviation. The engine rotation stop position control device according to claim 1 or 2, wherein the control means is controlled. In-cylinder pressure detecting means for detecting the pressure in each combustion chamber;
And a deceleration torque estimating means for estimating a deceleration torque applied to the rotating shaft based on a value detected by the in-cylinder pressure detecting means, wherein the control means rotates the rotation according to the estimated deceleration torque. 4. The engine rotation stop position control device according to claim 1, wherein the control of the adjusting means is corrected.   5. The engine rotation according to claim 4, wherein the control unit changes the cylinder that first stops the supply of the fuel by the fuel supply unit according to the estimated deceleration torque. Stop position control device.   6. The engine rotation stop position control device according to claim 5, wherein the control means obtains the target rotation speed based on the estimated deceleration torque.

Images