JP2016113904A - Rotation stop position control device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect an engine rotating speed while suppressing influence by product dispersion and assembling error of rotation speed detecting means.SOLUTION: An engine 1 is a reciprocal engine rotating a crank shaft 3 by burning a fuel supplied by an injector 32. An electronic throttle device 7 disposed in an intake passage 4 is used to regulate rotation of the crank shaft 3 in stopping the engine 1. An electronic control unit (ECU) 50 controls an electronic throttle device 7 so that an engine rotation speed detected by a rotation speed sensor 45 after stopping the fuel supply by the injector 32, reaches a prescribed target rotation speed, thus the crank shaft 3 is stopped at a prescribed crank position. The ECU 50 measures a lapse time necessary for the crank shaft 3 to rotate 360°CA as a prescribed angle from a specific crank position, and calculates the engine rotation speed on the basis of 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.

  Here, Patent Document 1 does not specifically describe the configuration of the rotational speed sensor, but generally, as shown in FIG. 7, the rotational speed sensor 65 is configured by a crank sensor made of an MR element, and is an engine. The timing rotor 78 is fixed to one end of the crankshaft 73 so as to face the outer periphery of the timing rotor 78. A plurality of protrusions (teeth) 78a are formed on the outer periphery of the timing rotor 78, and the rotational speed sensor 65 is disposed so as to face each tooth 78a. Most of the plurality of teeth 78a are, for example, formed at intervals of 10 ° C., and are missing teeth 78b formed at intervals of 30 ° C. at only one place. The rotation speed sensor 65 detects the passage of each tooth 78a and outputs a pulse signal when the timing rotor 78 rotates as the crankshaft 73 rotates. The engine speed can be determined from the elapsed time between successive pulse signals.

JP 2005-155548 A

  However, the detection value of the engine rotation speed by the rotation speed sensor 65 may vary due to product variations of the timing rotor 78, assembly errors of the timing rotor 78 with respect to the crankshaft 73, and the like. Therefore, in the apparatus of Patent Document 1, even if the actual engine rotational speed is the same, the rotational speed detected by the rotational speed sensor 65 may differ depending on the rotational position of the timing rotor 78. Further, in the apparatus of Patent Document 1, when the engine rotational speed is relatively high, the detection variation becomes large, and there is a possibility that the opening degree of the throttle valve cannot be controlled with high accuracy.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the influence of product variation of the rotational speed detecting means and assembly errors in order to suitably control the rotation stop position of the engine. An object of the present invention is to provide an engine rotation stop position control device capable of accurately detecting a rotation speed.

  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 fuel supply means. And a rotation adjusting means for adjusting the rotation of the rotation shaft, and a rotation speed detection for detecting the rotation speed of the rotation shaft. And rotation adjustment so that the rotation speed detected by the rotation speed detection means becomes a predetermined target rotation speed after stopping the fuel supply by the fuel supply means to stop the rotation shaft at the predetermined rotation position. In an engine rotation stop position control device comprising control means for controlling the means, the elapsed time taken to rotate the rotation shaft from the specific rotation position of the rotation shaft by a predetermined angle is measured. And, the spirit further comprising a rotation speed calculation means for calculating 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 rotation speed calculation means measures an elapsed time required to rotate the rotation shaft from the specific rotation position of the rotation shaft by a predetermined angle, and calculates the rotation speed of the rotation shaft from the elapsed time. Therefore, even if there is a variation in the rotational speed calculated from the elapsed time taken to rotate a predetermined angle from a different rotational position at each rotational speed calculation timing, a specific rotation that periodically arrives every time the rotational axis rotates by a predetermined angle By starting the measurement of the elapsed time from the position, the variation in the calculated rotational speed is eliminated.

  In order to achieve the above object, the invention according to claim 2 is the invention according to claim 1, wherein the engine is a reciprocating engine and the specific rotational position is ATDC 3 ° C. .

  According to the configuration of the invention, in addition to the operation of the invention according to claim 1, in the reciprocating engine, the specific rotational position serving as a reference for calculating the rotational speed is ATDC 3 ° C. The gradient of the decrease in angular velocity associated with the rotation of the rotation is the largest, and is the most suitable position for identifying the difference in rotation speed.

  To achieve the above object, the invention according to claim 3 is the invention according to claim 1 or 2, wherein the engine includes a cylinder having a combustion chamber for burning fuel, In-cylinder pressure detecting means for detecting the pressure, and deceleration torque estimating means for estimating the deceleration torque applied to the rotating shaft based on the value detected by the in-cylinder pressure detecting means, and the control means includes the estimated deceleration torque The purpose is to correct the control of the rotation adjusting means in accordance with the size of.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 1 or 2, 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.

  To achieve the above object, according to a fourth aspect of the present invention, in the third aspect of the present invention, the engine includes a plurality of cylinders having combustion chambers, and the fuel supply means supplies fuel to each cylinder. The control means is configured to change the cylinder that first stops the fuel supply by the fuel supply means in accordance with the estimated magnitude of the deceleration torque.

  According to the configuration of the invention described above, in addition to the action of the invention according to claim 3, the control means changes the cylinder that first stops the fuel supply by the fuel supply means according to the estimated magnitude of the deceleration torque. Therefore, 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 fifth aspect of the present invention is based on the fourth aspect of the present invention, wherein the control means obtains the target rotational speed based on the estimated deceleration torque.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 4, since the target rotational speed at which the rotational speed is to be adjusted is obtained based on the estimated deceleration torque, the rotational adjustment means is more than necessary. There is no need to control.

  According to the first aspect of the present invention, it is possible to accurately detect the rotational speed of the engine while suppressing the influence of product variation of the rotational speed detecting means and assembly errors without adding a new configuration.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the rotational speed of the engine can be detected more accurately, and the rotational shaft can be more accurately detected at a predetermined rotational position. Can be stopped.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the rotation of the rotary shaft can be stopped at a predetermined rotational position with high accuracy.

  According to the fourth aspect of the invention, in addition to the effect of the third 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 fifth aspect of the invention, in addition to the effect of the fourth aspect of the invention, the rotation adjusting means is not driven unnecessarily, the use time can be shortened, and the power consumption is suppressed. Can do.

1 is a schematic configuration diagram illustrating an engine system according to a first embodiment. The flowchart which shows the content of 1st Embodiment and the rotation stop position control of an engine. The graph which shows the relationship of the angular acceleration which concerns on 1st Embodiment and the crank angle (crank position) just before an engine stop and rotation of a crankshaft. The flowchart which concerns on 2nd Embodiment and shows the content of the rotation stop position control of an engine. Map data referred to for obtaining a rotation speed threshold value (NES) according to the deceleration torque deviation (ΔTR) according to the second embodiment. The flowchart which shows the content of 3rd Embodiment and the rotation stop position control of an engine. The front view which concerns on a prior art example and shows the relationship between a rotational speed sensor and a timing rotor.

<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 a plurality of 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 sucked into 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. 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.

  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. The configuration of the sensor 45 is the same as that described with reference to FIG. 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 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 and the rotation speed calculation 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 in order to stop the engine 1, the electronic throttle device 7 is operated to open the throttle valve 9, thereby changing the deceleration torque of the engine 1 and the engine speed. The NE is adjusted.

  Next, engine rotation stop position control in idling stop control will be described. FIG. 2 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 sequentially stops the fuel supply by the injectors 32 and starts the engine 1 to stop.

  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 detects the engine speed NE at a specific crank position every 360 ° C. A (every time the crankshaft 3 makes one rotation). Here, the specific crank position corresponds to a specific rotational position of the crankshaft 3 and is set to “ATDC 3 ° C. A” in this embodiment. That is, the ECU 50 detects the engine speed NE every time the crankshaft 3 makes one rotation with the ATDC 3 ° C. as a reference. At this time, the ECU 50 measures the elapsed time required to rotate the crankshaft 3 from the ATDC 3 ° C. to a predetermined angle of 360 ° C., and calculates the engine rotational speed NE from the elapsed time. FIG. 3 is a graph showing the relationship between the crank angle (crank position) just before the engine stops and the angular acceleration related to the rotation of the crankshaft 3. The specific crank position is “ATDC3 ° C. A” as shown in FIG. 3, where the crank position is a position where the positive and negative angular accelerations are reversed, and the gradient of the decrease in the angular velocity related to the rotation of the crankshaft 3 is the largest. Because it grows.

  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 calculated as described above is at a predetermined target rotational speed (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, the engine 1 can be started by itself by supplying fuel to the cylinder 2 and burning it when the engine 1 is restarted.

  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 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 of the crankshaft 3 based on the detection 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 measures an elapsed time from the specific crank position “ATDC3 ° C. A” to the rotation of the crankshaft 3 by 360 ° C. A, and calculates the engine rotational speed NE from the elapsed time. Therefore, even if there is a variation in the rotational speed calculated from the elapsed time required to rotate a predetermined angle from a different crank position at each rotational speed calculation timing, the specific that periodically arrives every time the crankshaft 3 rotates 360 ° C. By starting the measurement of the elapsed time from the crank position, the variation in the calculated rotational speed is eliminated. For this reason, it is possible to accurately detect the engine rotational speed NE while suppressing the influence of product variations and assembly errors of the rotational speed sensor 45 and the timing rotor 28 without adding a new configuration. As a result, when the engine 1 is stopped, the rotation stop position control can be started from a state where the engine rotational speed NE is relatively high so that the crankshaft 3 can be stopped at a predetermined crank position.

  In this embodiment, in the reciprocating engine, the specific crank position that serves as a reference for calculating the engine rotational speed NE is “ATDC 3 ° C. A”, and therefore, the gradient of the angular speed decrease related to the rotation of the crankshaft 3 at the crank position is The position is the largest and is the most suitable position for identifying the difference in engine speed NE. For this reason, the engine speed NE can be detected more accurately, and the crankshaft 3 can be stopped more accurately at the predetermined crank position.

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 unit in addition to the control unit and the rotation speed calculating unit. FIG. 4 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 processing shifts to this routine, in step 200, the ECU 50 generates the deceleration torque TR0 determined by the in-cylinder pressure PS detected by the in-cylinder pressure sensor 42 and the crank mechanism (for example, the crankshaft 3 of the 8-cylinder engine). presume. 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 (fuel cut start cylinder) SFC where fuel cut should be started first in accordance with the calculated deceleration torque deviation ΔTR. Ask for. Here, the ECU 50 can obtain the rotation speed threshold NES corresponding to the deceleration torque deviation ΔTR by referring to map data as shown in FIG. 5, for example. 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 detects the engine speed NE at a specific crank position every 360 ° C. A (every time the crankshaft 3 makes one rotation). In this embodiment, the specific crank position is set to “ATDC 3 ° C. A”. That is, the ECU 50 detects the engine rotation speed NE every time the crankshaft 3 rotates 360 ° C. from ATDC 3 ° C. which is a specific crank position. At this time, the ECU 50 measures the elapsed time required to rotate the crankshaft 3 from ATDC 3 ° C. to 360 ° C. A, and calculates the engine speed NE from the elapsed time.

  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 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 of the crankshaft 3 based on the detection 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 first stops the fuel supply by the injector 32 in the predetermined cylinder 2 (fuel cut start cylinder SFC). After that, the electronic throttle device 7 is controlled so that the engine rotational speed NE detected by the rotational speed sensor 45 becomes 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 measures an elapsed time from the specific crank position “ATDC3 ° C. A” to the rotation of the crankshaft 3 by 360 ° C. A, and calculates the engine rotational speed NE from the elapsed time. Therefore, even if there is a variation in the rotational speed calculated from the elapsed time required to rotate a predetermined angle from a different crank position at each rotational speed calculation timing, the specific that periodically arrives every time the crankshaft 3 rotates 360 ° C. By starting the measurement of the elapsed time from the crank position, the variation in the calculated rotational speed is eliminated. For this reason, it is possible to accurately detect the engine rotational speed NE while suppressing the influence of product variations and assembly errors of the rotational speed sensor 45 and the timing rotor 28 without adding a new configuration. As a result, when the engine 1 is stopped, the rotation stop position control can be started from a state where the engine rotational speed NE is relatively high so that the crankshaft 3 can be stopped at a predetermined crank position.

  In this embodiment, in the reciprocating engine, the specific crank position that serves as a reference for calculating the engine rotational speed NE is “ATDC 3 ° C. A”, and therefore, the gradient of the angular speed decrease related to the rotation of the crankshaft 3 at the crank position is The position is the largest and is the most suitable position for identifying the difference in engine speed NE. For this reason, the engine speed NE can be detected more accurately, and the crankshaft 3 can be stopped more accurately at the predetermined crank position.

  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 cylinder 2 at which the fuel cut by the injector 32 is first started according to the estimated deceleration torque TR0, so that the deceleration of the crankshaft 3 to be adjusted by the electronic throttle device 7 is performed. The amount of torque 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. If the engine is 8 cylinders, it is only necessary to change the cylinder at which fuel cut is first started, and only to correct the crank angle by “90 ° C. A” at the maximum. Can be quickly stopped at the 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 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. 6 is a flowchart showing the contents of the rotation stop position control. The flowchart of FIG. 6 differs from steps 250, 260, and 270 of the flowchart of FIG. 4 in the contents of steps 255, 265, and 275.

  That is, in step 255 of FIG. 6, the ECU 50 detects the engine rotational speed NE at a specific crank position after the expansion TDC every 360 ° C. A (each time the crankshaft 3 makes one rotation). In this embodiment, the specific crank position is set to “ATDC 3 ° C. A”. That is, the ECU 50 detects the engine rotational speed NE every time the crankshaft 3 rotates 360 ° C. A with reference to ATDC 3 ° C. A. At this time, the ECU 50 measures the elapsed time required to rotate the crankshaft 3 from ATDC 3 ° C. to 360 ° C. A, and calculates the engine speed NE from the elapsed time.

  In step 265 of FIG. 6, 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 (rotational speed within a predetermined range).

  Further, in step 275 of FIG. 6, 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.

  In each of the above embodiments, the rotation adjusting means is constituted by the electronic throttle device 7, but the invention is not limited to this, and any other device can be used as long as it is a means capable of adjusting the rotational speed of the rotating shaft of the engine. . 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.

  In each embodiment, the elapsed time required to rotate the “360 ° C. A” that is a predetermined angle from the specific crank position is measured, and the engine speed NE is calculated from the elapsed time, but the predetermined angle is “30 ° C. A ”or“ 520 ° C. A ”may be used.

  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 (rotation adjustment 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, rotation speed calculation means, deceleration torque estimation means)

Claims (5)

An engine rotation stop position control device for controlling an engine rotation shaft to stop at a predetermined rotation position,
The engine is configured to rotate the rotating shaft by burning fuel supplied by fuel supply means;
Rotation adjusting means for adjusting the rotation of the rotating shaft;
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 supply of fuel by the fuel supply means is stopped, and then the rotation speed detected by the rotation speed detection means becomes a predetermined target rotation speed. In the engine rotation stop position control device comprising a control means for controlling the rotation adjusting means,
Rotating speed calculation means for measuring an elapsed time required to rotate the rotating shaft by a predetermined angle from a specific rotating position of the rotating shaft and calculating a rotating speed of the rotating shaft from the elapsed time. An engine rotation stop position control device.   The engine rotation stop position control device according to claim 1, wherein the engine is a reciprocating engine, and the specific rotation position is ATDC3 ° C. The engine includes a cylinder having a combustion chamber for burning the fuel;
In-cylinder pressure detecting means for detecting the pressure in the 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. The engine rotation stop position control apparatus according to claim 1 or 2, wherein the control of the adjusting means is corrected. The engine includes a plurality of cylinders having the combustion chamber, and the fuel supply means is configured to supply fuel for each of the cylinders,
4. The engine rotation according to claim 3, 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. 5. Stop position control device.   5. The engine rotation stop position control device according to claim 4, wherein the control means obtains the target rotation speed based on the estimated deceleration torque.

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