JP2009002202A - Starting device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a starting device for an internal combustion engine capable of appropriately inhibiting excessive load from being applied on a starting device by suitably estimating reverse rotation of a crankshaft. <P>SOLUTION: Speed drop quantity ΔNE1 which is difference between first rotation speed NE1 at a point of time of suspension of combustion of air fuel mixture and second engine rotation speed NE2 after a predetermined period of time α elapses from the suspension of combustion of the air fuel mixture is calculated, and reverse rotation torque action period RP during which reverse rotation torque of a crankshaft acts on the starting device is estimated based on the speed drop quantity ΔNE. Drive of a starter motor is prohibited during the estimated reverse rotation torque action period RP. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

The internal combustion engine is started by transmitting the rotational force of the starter motor to the crankshaft via a driving force transmission mechanism such as a gear mechanism.
On the other hand, when the engine is stopped, immediately before the rotation of the crankshaft stops, the crankshaft may reversely rotate due to the reaction force of the air compressed in the cylinder. During such reverse rotation, the starter The reverse rotation torque of the crankshaft acts on a starting mechanism such as a motor or a driving force transmission mechanism.

  If the starter motor is driven during the reverse rotation of the crankshaft based on an engine start operation or the like, the starter motor rotates in the forward direction against the reverse rotation torque of the crankshaft. Therefore, an excessive load may be applied to the starting mechanism.

Therefore, in the apparatus described in Patent Document 1, driving of the starter motor is prohibited when the crankshaft rotates in the reverse direction. In this apparatus, whether or not the crankshaft is rotating in reverse is directly detected by a sensor, or reverse rotation of the crankshaft is predicted based on the compressed state of air in the cylinder.
JP 2005-140030 A

  By the way, after the reverse rotation of the crankshaft is detected, it takes a certain amount of processing time to complete the process of prohibiting the starter motor drive. Therefore, before such a drive prohibition process is completed, there is a possibility that the starter motor is driven even if the crankshaft rotates in the reverse direction.

  In order to suppress the occurrence of such inconvenience, it is necessary to ensure the above processing time, and in order to ensure such processing time, it is desirable to predict in advance rather than detecting reverse rotation of the crankshaft. Here, in the above document, the reverse rotation of the crankshaft is predicted based on the compressed state of the air in the cylinder. However, if it is determined that the crankshaft rotates reversely based on the compressed state of the air, immediately thereafter There is a possibility that reverse rotation may occur, and there is a possibility that the processing time cannot be sufficiently ensured in the prediction mode described in the above document.

  The present invention has been made in view of such circumstances, and its purpose is to more appropriately suppress a state in which an excessive load is applied to the starting mechanism by more appropriately predicting reverse rotation of the crankshaft. It is an object of the present invention to provide a starter for an internal combustion engine that can be used.

In the following, means for achieving the above object and its effects are described.
According to a first aspect of the present invention, there is provided a starting mechanism having a starter motor for starting an internal combustion engine, a driving force transmission mechanism for transmitting a driving force of the starter motor to a crankshaft, and a control means for controlling the driving of the starter motor. In the internal combustion engine starter, the control means has a reverse rotation torque action period in which the reverse rotation torque of the crankshaft acts on the start mechanism during the engine rotation speed after the combustion of the air-fuel mixture is stopped. The gist is that the starter motor is prohibited during the estimated reverse rotation torque operation period based on the degree of decrease.

  When combustion of the air-fuel mixture is stopped by stopping fuel injection or fuel ignition, the rotational speed of the crankshaft in the forward rotation direction (rotation direction during engine operation) decreases, and the forward rotation direction Once the rotational speed of the crankshaft reaches “0”, reverse rotation of the crankshaft occurs. The time during which the rotational speed in the forward rotational direction becomes “0” can be estimated based on the degree of decrease in the engine rotational speed after the combustion of the air-fuel mixture is stopped. In addition, as the degree of decrease in the engine rotation speed increases, the kinetic energy of the piston increases. Therefore, the amount of lift of the piston after the rotation speed in the forward rotation direction becomes “0” increases. As a result, The air in the cylinder is more easily compressed. Accordingly, as the degree of decrease in the engine rotational speed is larger, the time from when the reverse rotational torque is generated until it disappears tends to be longer, and the duration of the reverse rotational torque can be estimated based on the degree of decrease. Is possible. Therefore, in the same configuration, the reverse rotation torque is applied from the reverse rotation torque operation period in which the reverse rotation torque of the crankshaft acts on the starting mechanism, that is, from the time when the rotation speed in the forward rotation direction of the crankshaft becomes “0”. The period until disappearance is estimated based on the degree of decrease in the engine speed after the combustion of the air-fuel mixture is stopped.

  Here, as described above, in the conventional apparatus in which the reverse rotation of the crankshaft is predicted by detecting the compressed state of the air in the cylinder, the reverse rotation is immediately performed after the crankshaft is predicted to reversely rotate. In this case, the process of prohibiting the starter motor drive is not in time.

  On the other hand, after combustion of the air-fuel mixture is stopped, it takes some time until the crankshaft starts reverse rotation. Therefore, when the reverse rotation torque acting period is estimated based on the degree of decrease in the engine speed after the combustion of the air-fuel mixture is stopped as in the same configuration, after the combustion of the air-fuel mixture is stopped, the crank Until the shaft starts reverse rotation, it is possible to secure the time for calculating the reverse rotation torque operation period and the time for completing the starter motor drive inhibition process.

  Thus, according to the same configuration, the reverse rotation of the crankshaft can be predicted more appropriately, that is, the reverse rotation torque operation period is estimated with a margin before the reverse rotation torque starts to act on the starting mechanism. Will be able to. Therefore, it is possible to complete the starter motor drive prohibition process before the reverse rotation torque starts to act on the starting mechanism, and more appropriately suppress the state in which an excessive load is applied to the starting mechanism. become able to. In the same configuration, the engine rotation speed after the combustion of the air-fuel mixture is stopped includes the engine rotation speed after at least one of fuel injection and fuel ignition is stopped.

  In the case of estimating the reverse rotation torque action period based on the degree of decrease in the engine speed after the combustion of the air-fuel mixture is stopped, the reverse rotation torque action period is calculated as follows. By adopting such a configuration that the longer the degree of decrease is estimated, the longer the reverse rotation torque acting period can be estimated.

  According to a third aspect of the present invention, in the internal combustion engine starter according to the first or second aspect, the control means uses the engine rotational speed at the time when combustion of the air-fuel mixture is stopped as a value indicating the degree of decrease. The gist of the present invention is to calculate a speed reduction amount that is a difference between the engine speed and a predetermined period after the combustion of the air-fuel mixture is stopped.

  Combustion of the air-fuel mixture was stopped as the difference between the engine speed at the time when the combustion of the air-fuel mixture was stopped and the engine speed after a predetermined period of time after the combustion of the air-fuel mixture was stopped was larger. The degree of subsequent reduction in engine speed is in a large state. Therefore, in the same configuration, a speed reduction amount that is a difference between the engine speed at the time when combustion of the air-fuel mixture is stopped and the engine speed after a predetermined period has elapsed after the combustion of air-fuel mixture is stopped is calculated. As a result, the degree of decrease in the engine speed after the combustion of the air-fuel mixture is stopped can be appropriately calculated.

  According to a fourth aspect of the present invention, in the internal combustion engine starter according to the third aspect, the reverse rotation torque acting period is estimated to be longer as the speed reduction amount is larger. To do.

According to the same configuration, the estimated value of the reverse rotation torque acting period becomes longer as the degree of decrease in the engine rotation speed is larger, so that the reverse rotation torque acting period can be estimated appropriately.
According to a fifth aspect of the invention, in the internal combustion engine starter according to the third or fourth aspect of the invention, the predetermined period is variably set based on the engine speed at the time when the combustion of the air-fuel mixture is stopped. Is the gist.

  In the case where the reverse rotation torque acting period is estimated based on the speed reduction amount, the reverse rotation torque starts to be detected when the engine rotation speed is detected after a predetermined period has elapsed after the combustion of the air-fuel mixture is stopped. The estimation accuracy can be improved by performing the process as close as possible to the time.

  Here, the time from when the combustion of the air-fuel mixture is stopped until the reverse rotation torque starts to occur (the crankshaft starts reverse rotation) is the high engine speed at the time when the combustion of the air-fuel mixture is stopped. It changes according to. Therefore, the ideal detection timing of the engine rotational speed that can improve the estimation accuracy of the reverse rotational torque acting period also changes according to the height of the engine rotational speed at the time when the combustion of the air-fuel mixture is stopped. Therefore, in the same configuration, when detecting the engine speed after a predetermined period has elapsed since the combustion of the air-fuel mixture was stopped, the predetermined period is determined based on the engine speed at the time when the combustion of the air-fuel mixture was stopped. Variable setting. Accordingly, the estimation accuracy of the reverse rotation torque acting period can be preferably improved.

  According to a sixth aspect of the present invention, in the internal combustion engine starter according to the fifth aspect of the invention, the predetermined period is increased as the engine rotational speed at the time when combustion of the air-fuel mixture is stopped increases. The gist.

  According to this configuration, the longer the time from when the combustion of the air-fuel mixture is stopped to when the reverse rotation torque starts to occur, the detection of the engine rotation speed after a predetermined period has elapsed, so the reverse rotation The estimation accuracy of the torque action period can be appropriately improved.

  According to a seventh aspect of the present invention, in the internal combustion engine starter according to any one of the first to sixth aspects, the driving force transmission mechanism transmits the driving force of the starter motor to the crankshaft. The gist thereof is that a clutch is provided, and a pinion gear provided on the output shaft of the starter motor and a ring gear provided on the crankshaft are always meshed with each other.

  The starting mechanism in this configuration is a so-called always-meshing type starting mechanism in which a one-way clutch is provided in the driving force transmission mechanism and the pinion gear and the ring gear are always meshed. Here, generally, since the rotational torque of the starter motor is transmitted to the crankshaft while being decelerated by the driving force transmission mechanism, when the starting mechanism such as the starter motor or the driving force transmission mechanism is rotated by the reverse rotation of the crankshaft. The rotational resistance of is very large. Therefore, in the always-meshing start mechanism, the crankshaft is reversely rotated, and in reality, the crankshaft is difficult to reversely rotate, and only the reverse rotation torque is mainly transmitted to the start mechanism. For this reason, when the reverse rotation of the crankshaft is actually detected to prohibit the starter motor from being driven, a reverse rotation state in which only such reverse rotation torque is transmitted to the starting mechanism cannot be detected. The motor drive prohibition process cannot be performed. In this regard, according to the above configuration, the period during which the reverse rotational torque acts on the starting mechanism from the crankshaft is estimated. Therefore, in practice, the crankshaft is difficult to reversely rotate, and the starter motor can be prohibited from driving even in a reverse rotation state in which only the reverse rotation torque is transmitted to the starting mechanism. Therefore, even in the always-meshing type start mechanism, the starter motor can be appropriately prohibited from being driven.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying a starter for an internal combustion engine according to the present invention will be described below with reference to FIGS.
FIG. 1 is a partial cross-sectional view of the vicinity of a rear end portion of an oil pan 2 provided in a vehicle-mounted internal combustion engine to which a starter according to the present invention is applied, which is provided below the internal combustion engine.

As shown in FIG. 1, a rear end of the crankshaft 6 that is rotatably supported by the ladder beam 4 is disposed above the rear end of the oil pan 2.
A flywheel 8, an outer race support plate 10 and a ring gear 12 are attached to the rear end of the crankshaft 6.

The outer race support plate 10 is fastened and fixed to the rear end of the crankshaft 6 together with the flywheel 8 by a bolt, and rotates together with the crankshaft 6.
The ring gear 12 is located on the outer peripheral portion of the rear end of the crankshaft 6 and is attached via the inner race 16 of the one-way clutch 14 and the bearing 18. When the one-way clutch 14 is in the non-engaged state, 12 can rotate independently of the rotation of the crankshaft 6. Further, a ring-shaped gear portion 12 a is formed on the peripheral edge portion of the ring gear 12. The gear portion 12 a is always meshed with a pinion gear 35 provided on the output shaft 34 of the starter motor 30, and rotates the ring gear 12 by receiving a rotational force from the starter motor 30. The number of teeth of the gear portion 12a is greater than the number of teeth of the pinion gear 35. When the starter motor 30 is driven to rotate, the rotational torque is transmitted to the crankshaft 6 in a decelerated state.

  The outer race 22 of the one-way clutch 14 is attached to the outer race support plate 10 so as to face the inner race 16 attached to the inner periphery of the ring gear 12. Thus, the one-way clutch 14 is provided between the ring gear 12 and the outer race support plate 10.

  The one-way clutch 14, the bearing 18, the outer race support plate 10, the ring gear 12, the pinion gear 35, and the like constitute a driving force transmission mechanism that transmits the driving force of the starter motor 30 to the crankshaft 6.

  When the starter motor 30 rotates the ring gear 12 via the pinion gear 35 when the engine is started, that is, when torque is transmitted from the ring gear 12 side, the outer race support plate 10 and the ring gear 12 are engaged by the one-way clutch 14. To be. Thereby, the crankshaft 6 is rotated by the starter motor 30, that is, cranking is performed.

  When the engine completes explosion, in other words, when the internal combustion engine rotates independently without borrowing the power of the starter motor 30, the rotational speed of the outer race support plate 10 linked to the crankshaft 6 is the rotational speed of the ring gear 12. And the one-way clutch 14 is disengaged, that is, the one-way clutch 14 is idling. As a result, the drive connection between the crankshaft 6 and the starter motor 30 is released.

  Oil is supplied to the bearing 18 and the one-way clutch 14 via an oil passage or the like in the cylinder block or the crankshaft 6, whereby the bearing 18 and the one-way clutch 14 are lubricated. Here, in order to suppress oil leakage from the one-way clutch 14 disposed between the outer race support plate 10 and the ring gear 12, the ring-shaped first seal member 24 is connected to the outer race 22 and the ring gear 12 of the one-way clutch 14. It is arranged between. The first seal member 24 is fixed to the ring gear 12 while being fitted to an inner peripheral surface 12c of a cylindrical step portion 12b formed in the middle of the ring gear 12. A seal lip 24a formed on the inner peripheral side of the first seal member 24 is slidably in contact with the outer peripheral surface of the outer race 22 to seal oil.

  A second seal member 26 having a larger diameter than the first seal member 24 is disposed on the opposite side of the first seal member 24 across the stepped portion 12b. The second seal member 26 is mainly on the inner peripheral surface 2b of the rear end 2a of the oil pan 2 below the crankshaft 6, and mainly on the inner peripheral surface of the rear end of the cylinder block above the crankshaft 6. It is mated. The seal lip 26a formed on the inner peripheral side of the second seal member 26 is slidably in contact with the outer peripheral surface 12d of the stepped portion 12b and seals oil.

  As described above, the start mechanism for starting the internal combustion engine in the present embodiment is a so-called always-mesh type start mechanism in which the pinion gear 35 and the gear portion 12a of the ring gear 12 are always meshed. The one-way clutch 14 releases the drive connection between the crankshaft 6 and the starter motor 30 at the start of the engine and the release of the drive connection between the crankshaft 6 and the starter motor 30 after the complete explosion of the engine. In the present embodiment, the driving force transmission mechanism is configured by the members disposed on the driving force transmission path from the pinion gear 35 of the starter motor 30 to the outer race support plate 10 fixed to the flywheel 8. ing.

  The control device 50 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a backup RAM, an external input circuit, an external output circuit, and the like. Various sensors for detecting the state of the internal combustion engine and the vehicle (for example, a crank angle sensor 40 for detecting the rotational speed of the crankshaft 6, that is, the engine rotational speed NE) are connected, and fuel injection is performed based on the detection result. Various controls such as quantity and ignition timing are performed. Further, an ignition switch 41 (hereinafter referred to as IG switch 41) that is switched by a vehicle driver and outputs a signal corresponding to the current operation position is also connected. When the IG switch 41 is operated to the starting position, that is, when the engine starting operation is performed, the starter motor 30 is driven, and fuel injection and fuel ignition are started to start the engine. On the other hand, when the IG switch 41 is turned off, that is, when the engine stop operation is performed, the engine operation is stopped by stopping the fuel injection and the fuel ignition and stopping the combustion of the air-fuel mixture. The control device 50 constitutes the control means.

  The control device 50 also executes automatic start and automatic stop control for automatically starting and stopping the internal combustion engine. For example, when the vehicle shifts from the running state to the stopped state, the internal combustion engine is automatically stopped. On the other hand, when it is determined that the vehicle transitions from the stop state to the start state based on the operation state of the brake pedal, etc., when the compressor is in the automatic stop state and there is a request for driving the compressor constituting the air conditioner, or during the automatic stop state If the automatic start condition is satisfied, such as when there is a battery charge request, the internal combustion engine is automatically started.

  By the way, when combustion of the air-fuel mixture is stopped by stopping fuel injection or fuel ignition, the rotational speed of the crankshaft in the forward rotation direction (rotation direction during engine operation) gradually decreases, and finally Specifically, the rotation of the crankshaft 6 stops. Immediately before the rotation of the crankshaft 6 stops, the crankshaft 6 may reversely rotate due to the reaction force of the air compressed in the cylinder.

  Here, when the reverse rotation of the crankshaft occurs when the pinion gear of the starter motor and the ring gear on the crankshaft are not meshed with each other, the crankshaft 6 rotates reversely, but the reverse rotation torque is not transmitted to the starting mechanism. On the other hand, since the reduction gear ratio on the starting mechanism side with respect to the ring gear is small, the rotational resistance from the crankshaft 6 side to the starting mechanism side is large. Therefore, when the reverse rotation of the crankshaft occurs when the pinion gear and the ring gear are engaged with each other, the crankshaft 6 is actually difficult to reversely rotate, and only the reverse rotation torque is mainly transmitted to the starting mechanism.

  Therefore, when the pinion gear 35 and the ring gear 12 are always meshed as in the starting mechanism of the present embodiment, the crankshaft 6 is actually difficult to reversely rotate while the reverse rotation of the crankshaft 6 occurs. Only the reverse rotation torque is transmitted to the starting mechanism.

  When the starter motor 30 is driven based on the engine start operation or the automatic start request in the state where the reverse rotation torque of the crankshaft 6 is applied to the start mechanism in this way, the starter motor 30 is connected to the crankshaft 6. The crankshaft 6 is rotated in the forward direction against the reverse rotation torque. Therefore, an excessive load may be applied to the components of the starting mechanism such as the starter motor 30, the one-way clutch 14, or the reduction gear.

  Therefore, in this embodiment, the reverse rotation torque action period RP in which the reverse rotation torque of the crankshaft 6 acts on the starting mechanism is estimated, and the starter motor 30 is prohibited from driving during the reverse rotation torque action period RP. I am doing so.

An estimation principle of the reverse rotation torque acting period RP in the present embodiment will be described with reference to FIGS.
FIG. 2 shows how the engine speed NE changes when the engine is stopped and how reverse torque is generated.

  As shown in FIG. 2, when combustion of the air-fuel mixture is stopped by stopping fuel injection or fuel ignition at time t1, the crankshaft 6 rotates in the forward rotation direction (rotation direction during engine operation). The speed decreases and the rotational speed in the forward rotational direction once becomes “0” (time t2). Then, immediately after the engine rotational speed NE becomes “0”, the reverse rotation torque of the crankshaft starts to be generated, and thereafter, after a certain amount of time has elapsed, the reverse rotation torque disappears (time t3).

  Here, the time from when the combustion of the air-fuel mixture is stopped until the rotational speed of the crankshaft 6 in the forward rotation direction becomes “0” (time t1 to time t2: hereinafter referred to as zero arrival time ZT) is mixed. This can be estimated based on the degree of decrease in the engine rotational speed NE after the combustion of the gas is stopped.

  Further, as the degree of decrease in the engine rotational speed NE increases, the kinetic energy of the piston in the cylinder increases, and therefore the amount of increase of the piston after the rotational speed in the forward rotational direction becomes “0” increases. As a result, the air in the cylinder is more easily compressed. Therefore, as the degree of decrease in the engine rotational speed NE is larger, the time from when the reverse rotational torque is generated until it disappears (time t2 to time t3) tends to be longer. Based on the degree of decrease, the reverse rotational torque is increased. It is also possible to estimate the operation period (time t2 to time t3).

  Therefore, in the present embodiment, the reverse rotational torque disappears from the reverse rotational torque operation period RP, that is, from the time when the rotational speed of the crankshaft 6 in the forward rotational direction becomes “0” (time t2) (time t3). The period up to is estimated based on the degree of decrease in the engine speed NE after the combustion of the air-fuel mixture is stopped.

  More specifically, as the difference between the engine rotational speed NE at the time when combustion of the air-fuel mixture is stopped and the engine speed NE after a predetermined period has elapsed since the combustion of the air-fuel mixture is stopped, the mixing is increased. The degree of decrease in the engine speed NE after the combustion of the gas is stopped is in a large state. Therefore, the engine rotational speed NE at the time when the combustion of the air-fuel mixture is stopped is set as the first rotational speed NE1, and the engine speed NE after a predetermined period has elapsed after the combustion of the air-fuel mixture is stopped is the second rotational speed NE2. As a value indicating the degree of decrease in the engine rotational speed NE, a speed decrease amount ΔNE that is the difference between the first rotational speed NE1 and the second rotational speed NE2 is calculated.

  Then, the time from when the combustion of the air-fuel mixture is stopped until the rotational speed of the crankshaft 6 in the forward rotation direction becomes “0”, that is, the zero arrival time ZT is estimated based on the speed decrease amount ΔNE.

  Further, the reverse rotation torque action period RP is estimated based on the speed decrease amount ΔNE, and the reverse rotation torque action period RP is added to the zero arrival time ZT, so that the reverse rotation torque is stopped after the combustion of the air-fuel mixture is stopped. Is calculated (hereinafter referred to as reverse rotation torque disappearance time DT).

  Then, the elapsed time T after the combustion of the air-fuel mixture is stopped is measured, and when the elapsed time T is not less than the zero arrival time ZT and not more than the reverse rotation torque extinction time DT, the drive of the starter motor 30 is prohibited. The drive prohibition flag F is held in the “ON” state to prohibit the starter motor 30 from being driven.

  Further, when the reverse rotation torque acting period RP is estimated based on the speed decrease amount ΔNE, the detection of the second rotation speed NE2 performed after a predetermined period has elapsed since the combustion of the air-fuel mixture is stopped is reversed. The estimation accuracy can be increased by performing the timing as close as possible to the timing at which the rotational torque starts to occur (time t2). More specifically, the processing time is calculated by adding the calculation time of the speed decrease amount ΔNE by the control device 50, the estimation processing time of the zero arrival time ZT, and the time for changing the drive inhibition flag F from “OFF” to “ON”. In the case of PT, it is ideal to detect the second rotational speed NE2 at a time before the processing time PT by the time t2. In this way, by detecting the second rotational speed NE2 at a time earlier than the time t2 by the processing time PT, the processing time PT is reliably secured and the starter motor 30 is driven while the reverse rotational torque is being generated. The second rotation speed NE2 can be detected at a time as close as possible to the time (time t2) when the reverse rotation torque starts to occur.

  The time preceding the time t2 by the processing time PT is “time t1 (time when combustion of the air-fuel mixture is stopped) −time t2 (time when reverse rotation torque starts to occur) −processing time PT = predetermined. In the case of “period α”, the time is “time t1 + predetermined period α”. Here, as shown in FIG. 3, the time from when the combustion of the mixture is stopped (time t1) to when the reverse rotation torque starts to occur (time t2) is the time when the combustion of the mixture is stopped. It changes according to the engine rotational speed NE, that is, the height of the first rotational speed NE1. More specifically, the higher the first rotational speed NE1, the longer the time from when the air-fuel mixture combustion is stopped until the reverse rotational torque starts to be generated. Therefore, the detection time of the ideal second rotation speed NE2 (time TS shown in FIGS. 2 and 3; hereinafter referred to as the second rotation speed detection time TS) that can improve the estimation accuracy of the reverse rotation torque operation period RP is also provided. In other words, the predetermined period α also changes according to the height of the engine speed NE at the time when the combustion of the air-fuel mixture is stopped. Specifically, the higher the first rotation speed NE1, the longer the predetermined period α and the later the second rotation speed detection time TS. Therefore, when detecting the second rotational speed NE2 after the elapse of a predetermined period α after the combustion of the air-fuel mixture is stopped, the predetermined period α is determined based on the engine speed at the time when the combustion of the air-fuel mixture is stopped, that is, By variably setting based on the first rotational speed NE1, the estimation accuracy of the reverse rotational torque acting period RP is increased.

  Next, referring to the flowchart shown in FIG. 4, the processing procedure for estimating the reverse rotation torque operation period RP, in other words, for estimating the zero arrival time ZT and the reverse rotation torque extinction time DT is as follows. explain. This estimation process is repeatedly executed by the control device 50 at predetermined intervals.

  When this process is started, it is first determined whether or not an engine stop condition is satisfied (S100). Here, an affirmative determination is made when the IG switch 41 is set to the OFF position or when the automatic stop condition is satisfied. Note that the automatic stop condition is that when the vehicle shifts from the running state to the stopped state, after the automatic start, the request for driving the compressor is canceled, or after the automatic start, the charge request for the battery is canceled. When it is done.

When the engine stop condition is not satisfied (S100: NO), this process is temporarily terminated.
On the other hand, when the engine stop condition is satisfied (S100: YES), it is determined whether or not it is immediately after the fuel injection is stopped (S110). If the fuel injection is not immediately after being stopped (S110: NO), this process is temporarily terminated.

  On the other hand, if it is immediately after the fuel injection is stopped, the first rotation speed NE1 that is the engine rotation speed at the time when the combustion of the air-fuel mixture is stopped is detected (S120), and the first rotation is performed. The second rotation speed detection time TS is set based on the speed NE1 (S130). In setting the second rotation speed detection time TS, as shown in FIG. 5, the second rotation speed detection time TS is variably set so as to increase as the first rotation speed NE1 increases. Then, according to such a setting mode, the detection of the second rotational speed NE2 after the predetermined period α has elapsed becomes longer as the time from when the combustion of the air-fuel mixture is stopped until the reverse rotational torque starts to be generated becomes longer. As a result, the estimation accuracy of the reverse rotational torque acting period RP is improved.

  Next, the measurement of the elapsed time T after the fuel injection is stopped is started (S140). Then, it is determined whether or not the elapsed time T has reached the second rotational speed detection time TS (S150). If the elapsed time T has not yet reached the second rotational speed detection time TS (S150: NO). ), Until the elapsed time T reaches the second rotation speed detection time TS, the determination process in step S150 is repeated.

  On the other hand, when the elapsed time T has reached the second rotation speed detection time TS (S150: YES), the second rotation speed NE2 is detected (S160), and the first rotation is started from the second rotation speed NE2. The speed decrease amount ΔNE obtained by subtracting the speed NE1 is calculated (S170).

  Next, the zero arrival time ZT and the reverse rotation torque operation period RP are calculated based on the speed decrease amount ΔNE (S180). Here, the reduction speed of the engine rotation speed NE is calculated based on the speed decrease amount ΔNE and the second rotation speed detection time TS, and the engine rotation speed NE is “0” based on the decrease speed and the second rotation speed NE2. ", That is, the zero arrival time ZT is estimated. Further, as the degree of decrease in the engine speed after the combustion of the air-fuel mixture is stopped, that is, as the speed decrease amount ΔNE is larger, the time until the reverse rotation torque is generated and disappears tends to be longer. It is in. Therefore, as shown in FIG. 6, the reverse rotational torque acting period RP is variably set so that the reverse rotational torque acting period RP becomes longer as the speed decrease amount ΔNE is larger.

  Next, the reverse rotation torque disappearance time DT is calculated based on the zero arrival time ZT and the reverse rotation torque operation period RP (S190). Here, by adding the reverse rotation torque action period RP to the zero arrival time ZT, the reverse rotation torque disappearance time DT, which is the time from when the combustion of the air-fuel mixture is stopped until the reverse rotation torque disappears, is calculated. The And this process is once complete | finished.

  Next, the driving process of the starter motor 30 will be described with reference to the flowchart shown in FIG. The starter motor driving process is also repeatedly executed by the control device 50 at predetermined intervals.

  When this process is started, it is first determined whether or not an engine start condition is satisfied (S200). Here, an affirmative determination is made when the IG switch 41 is in the start position or when the automatic start condition is satisfied. If the engine start condition is not satisfied (S200: NO), this process is temporarily terminated.

  On the other hand, if the engine start condition is satisfied (S200: YES), it is determined whether or not it is currently within a drive prohibition period NS in which the drive of the starter motor 30 is prohibited (S210). As the drive inhibition period NS, a period that satisfies the following equation (1) is set based on the zero arrival time ZT, the reverse rotation torque disappearance time DT, and the elapsed time T after the fuel injection is stopped.

Zero arrival time ZT ≦ elapsed time T ≦ reverse rotation torque disappearance time DT (1)

As shown in the equation (1), the drive inhibition period NS is a period that coincides with the reverse rotation torque operation period RP.

If it is within the drive inhibition period NS (S210: YES), the determination process in step S210 is repeated until the drive inhibition period NS is exited.
On the other hand, when it is not within the drive inhibition period NS (S210: NO), the starter motor 30 is started to be driven (S220).

  Next, it is determined whether or not the internal combustion engine has completely exploded (S230). Here, for example, an affirmative determination is made when the engine speed NE exceeds a predetermined value. If the complete explosion has not been completed (S230: NO), the determination process in step S230 is repeated until the complete explosion is completed.

On the other hand, when the internal combustion engine is completely detonated (S230: YES), the drive of the starter motor 30 is stopped (S240), and this process is terminated.
Thus, in the present embodiment, the reverse rotation torque operation period RP is estimated by executing the above estimation process. Then, when the starter motor drive process is executed, the starter motor 30 is prohibited from being driven within the reverse rotation torque action period RP, and thus the starter motor 30 is driven to the start mechanism due to the reverse rotation torque of the crankshaft 6. Excessive load input is suppressed.

  Here, in the above-described conventional apparatus in which the reverse rotation of the crankshaft is predicted by detecting the compressed state of the air in the cylinder, the reverse rotation may occur immediately after the crankshaft is predicted to reversely rotate. In this case, there is a possibility that the process of prohibiting the starter motor drive may not be in time.

  On the other hand, after combustion of the air-fuel mixture is stopped, it takes some time until reverse rotation torque of the crankshaft 6 starts to be generated. Therefore, as in the estimation process of the present embodiment, the following effect is obtained when the reverse rotation torque operation period RP is estimated based on the degree of decrease in the engine rotation speed NE after the combustion of the air-fuel mixture is stopped. Is obtained. That is, after the combustion of the air-fuel mixture is stopped and before the reverse rotation torque starts to be generated, a time for calculating the reverse rotation torque action period RP and a time for completing the drive prohibition process of the starter motor 30 are ensured. Is possible.

  Therefore, the generation period of the reverse rotation torque of the crankshaft 6 can be predicted more appropriately, that is, the reverse rotation torque operation period RP is estimated with a margin before the reverse rotation torque starts to act on the starting mechanism. Will be able to. Therefore, it is possible to complete the drive prohibition process of the starter motor 30 before reverse rotation torque starts to act on the starting mechanism, and more appropriately suppress a state in which an excessive load is applied to the starting mechanism. Can do.

  Further, the starting mechanism in the present embodiment is a so-called always-meshing type starting mechanism in which the driving force transmission mechanism is provided with the one-way clutch 14 and the pinion gear 35 and the ring gear 12 are always meshed. Here, as described above, since the rotational torque of the starter motor 30 is transmitted to the crankshaft 6 while being decelerated by the driving force transmission mechanism, the starting mechanism such as the starter motor 30 or the driving force transmission mechanism is applied to the crankshaft 6. The rotational resistance when rotating by reverse rotation is very large. Therefore, in the always-meshing start mechanism, the crankshaft 6 is in the reverse rotation, and in fact, the crankshaft 6 is difficult to reversely rotate, and only the reverse rotation torque is mainly transmitted to the start mechanism. Therefore, when the reverse rotation of the crankshaft 6 is actually detected to prohibit the starter motor 30 from being driven, a reverse rotation state in which only such reverse rotation torque is transmitted to the starting mechanism cannot be detected. Therefore, the drive prohibiting process of the starter motor 30 cannot be performed. In this regard, in this embodiment, the period during which the reverse rotational torque acts on the starting mechanism from the crankshaft 6 is estimated. Therefore, in practice, the crankshaft 6 is difficult to reversely rotate, and the drive of the starter motor 30 can be prohibited even in a reverse rotation state where only the reverse rotation torque is transmitted to the starting mechanism. Therefore, the starter motor 30 can be appropriately prohibited from being driven even in the always-mesh start mechanism.

As described above, according to the present embodiment, the following effects can be obtained.
(1) A reverse rotation torque action period RP in which the reverse rotation torque of the crankshaft 6 acts on the starting mechanism is estimated based on the degree of decrease in the engine rotation speed after the combustion of the air-fuel mixture is stopped, and the estimation During the reverse rotation torque action period RP, the drive of the starter motor 30 is prohibited. As a result, the reverse rotation of the crankshaft 6 can be predicted more appropriately, and a state in which an excessive load is applied to the starting mechanism can be more appropriately suppressed.

  (2) Since the reverse rotational torque acting period RP is estimated to be longer as the degree of decrease in the engine rotational speed is larger, the reverse rotational torque acting period RP can be appropriately estimated. .

  (3) As a value indicating the degree of decrease, the engine rotational speed (first rotational speed NE1) at the time when combustion of the air-fuel mixture is stopped and the engine after a predetermined period α has elapsed since the combustion of the air-fuel mixture is stopped. A speed decrease amount ΔNE, which is a difference from the rotational speed (second rotational speed NE2), is calculated. Accordingly, it is possible to appropriately calculate the degree of decrease in the engine speed after the combustion of the air-fuel mixture is stopped.

  (4) It is estimated that the reverse rotation torque acting period RP becomes longer as the speed decrease amount ΔNE is larger. For this reason, the estimated value of the reverse rotation torque action period RP becomes longer as the degree of decrease in the engine rotation speed is larger, and the reverse rotation torque action period RP can be appropriately estimated.

  (5) The predetermined period α is variably set based on the engine rotational speed (first rotational speed NE1) when combustion of the air-fuel mixture is stopped. More specifically, the second rotation speed detection time TS that is the detection timing of the second rotation speed NE2 that is the engine rotation speed after a predetermined period α has elapsed since the combustion of the air-fuel mixture was stopped is variably set. Like to do. Therefore, the estimation accuracy of the reverse rotation torque action period RP can be preferably increased.

  (6) The predetermined period α is set to be longer as the engine rotational speed (first rotational speed NE1) at the time when combustion of the air-fuel mixture is stopped is higher. Therefore, as the time from when the combustion of the air-fuel mixture is stopped until the reverse rotation torque starts to be generated becomes longer, the detection of the engine rotation speed after the predetermined period α has passed becomes slower, and the reverse rotation torque operation period The estimation accuracy of RP can be improved appropriately.

  (7) An always-meshing starter mechanism that includes the one-way clutch 14 that transmits the driving force of the starter motor 30 to the crankshaft 6 and that the pinion gear 35 of the starter motor 30 and the ring gear 12 provided on the crankshaft 6 side are always meshed. In the internal combustion engine including the above, the estimation process and the starter motor driving process are performed. Therefore, during the reverse rotation of the crankshaft 6, the crankshaft 6 is actually difficult to reversely rotate, and the starter motor 30 is prohibited from being driven even in the reverse rotation state where only the reverse rotation torque is transmitted to the starting mechanism. Therefore, even in the always-meshing start mechanism, the drive of the starter motor 30 can be appropriately prohibited.

In addition, the said embodiment can also be changed and implemented as follows.
Although the speed decrease amount ΔNE is calculated as a value indicating the degree of decrease in engine rotation speed, other values may be calculated. For example, the reduction speed of the engine rotation speed may be calculated.

  The detection timing of the first rotational speed NE1 is the timing immediately after the combustion of the air-fuel mixture is stopped, but if the timing is at least before the second rotational speed detection time TS, the detection timing is It may be changed.

  -Although the second rotation speed detection time TS is variably set, it may be set to a fixed value. For example, the second rotation speed detection time TS optimized when the first rotation speed NE1 is the idle rotation speed may be set.

  In the above embodiment, the zero arrival time ZT, which is the time from when the combustion of the air-fuel mixture is stopped until the rotational speed of the crankshaft 6 in the forward rotation direction becomes “0”, is estimated. In addition, when the rotational speed of the crankshaft 6 in the forward rotation direction becomes “0”, the drive prohibition flag F can be quickly turned from “OFF” to “ON” without delay. For example, instead of estimating the zero arrival time ZT, it may be detected that the rotational speed has become “0”.

  -The starting mechanism in the said embodiment was a constant meshing type starting mechanism. In addition, the above-described inconvenience may occur even in a starting mechanism in which the pinion gear of the starter motor and the ring gear on the crankshaft side mesh only when the engine is started. That is, when the starter motor 30 is driven during the reverse rotation of the crankshaft 6 based on the engine start operation or the automatic start request and the pinion gear and the ring gear are engaged with each other, the starter motor 30 is connected to the crankshaft 6. The crankshaft 6 is rotated in the forward direction against the reverse rotation torque. Therefore, an excessive load may be applied to the components of the starting mechanism such as a starter motor and a reduction gear. By applying the present invention to the starting mechanism in which the pinion gear of the starter motor and the ring gear on the crankshaft are engaged only at the time of starting the engine, the reverse rotational torque of the crankshaft can be reduced in the same manner as in the above embodiment. The excessive load input to the starting mechanism resulting from this can be suppressed appropriately.

  -Although the internal combustion engine in the said embodiment was what automatic start and automatic stop were performed, this invention applies similarly also to the start device of the internal combustion engine in which such automatic start and automatic stop are not performed. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the structure about one Embodiment of the starting device concerning this invention. The timing chart which shows the change aspect of the engine speed at the time of an engine stop, and the generation | occurrence | production aspect of reverse rotation torque. The timing chart which shows the change aspect about the time until the reverse rotation torque begins to generate | occur | produce after the combustion of air-fuel mixture is stopped. The flowchart which shows the process sequence of the estimation process in the embodiment. The graph which shows the relationship between 1st rotation speed and 2nd rotation speed detection time. The graph which shows the relationship between speed fall amount and reverse rotation torque extinction time. The flowchart which shows the process sequence of the starter motor drive process in the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Oil pan, 2a ... Rear end, 2b ... Inner peripheral surface, 4 ... Ladder beam, 6 ... Crankshaft, 8 ... Flywheel, 10 ... Outer race support plate, 12 ... Ring gear, 12a ... Gear part, 12b ... Level difference Part, 12c ... inner peripheral surface, 12d ... outer peripheral surface, 14 ... one-way clutch, 16 ... inner race, 18 ... bearing, 22 ... outer race, 24 ... first seal member, 24a ... seal lip, 26 ... second seal member , 26a ... seal lip, 30 ... starter motor, 34 ... output shaft, 35 ... pinion gear, 40 ... crank angle sensor, 41 ... ignition switch (IG switch), 50 ... control device.

Claims (7)

An internal combustion engine starter comprising a starter motor having a starter motor for starting the internal combustion engine and a drive force transmission mechanism for transmitting the drive force of the starter motor to the crankshaft, and a control means for controlling the drive of the starter motor.
The control means estimates a reverse rotation torque action period in which the reverse rotation torque of the crankshaft acts on the start mechanism based on a degree of decrease in engine rotation speed after combustion of the air-fuel mixture is stopped, A starting device for an internal combustion engine, wherein the starter motor is prohibited from driving during the estimated reverse rotation torque acting period. The starter for an internal combustion engine according to claim 1, wherein the reverse rotation torque operation period is estimated to be longer as the degree of decrease is larger. The control means, as a value indicating the degree of decrease, is the difference between the engine speed at the time when combustion of the air-fuel mixture is stopped and the engine speed after a predetermined period has elapsed since the combustion of the air-fuel mixture is stopped. The internal combustion engine starter according to claim 1 or 2, wherein a certain amount of speed reduction is calculated. The starter for an internal combustion engine according to claim 3, wherein the reverse rotational torque acting period is estimated to be longer as the speed reduction amount is larger. 5. The internal combustion engine starter according to claim 3, wherein the predetermined period is variably set based on an engine speed at a time when combustion of the air-fuel mixture is stopped. The starter for an internal combustion engine according to claim 5, wherein the predetermined period is made longer as the engine speed at the time when combustion of the air-fuel mixture is stopped is higher. The driving force transmission mechanism includes a one-way clutch that transmits the driving force of the starter motor to the crankshaft, and a pinion gear provided on the output shaft of the starter motor and a ring gear provided on the crankshaft are always meshed with each other. The starter for an internal combustion engine according to any one of claims 1 to 6.

Images