JP2010031851A - Starter for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of quickly restarting an internal combustion engine even in a stop of the engine, in regard to a starter for the internal combustion engine. <P>SOLUTION: This starter for internal combustion engine comprises: a ring gear to be rotated, interlocking with a crankshaft of an internal combustion engine; a starter motor having a pinion engaged with the ring gear; and a pinion control device which allows the pinion to engage with the ring gear when engine speed is an average value or less of engine speed in the middle of lowering engine speed with fluctuation to stop the internal combustion engine and which prohibits the pinion to engage the ring gear when engine speed is higher than the average value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  2. Description of the Related Art There is known an internal combustion engine starter that automatically stops an internal combustion engine when the internal combustion engine stop condition is satisfied and automatically starts the internal combustion engine when the internal combustion engine start condition is satisfied.

  A technique is known in which the pinion is engaged with the ring gear when the start condition is satisfied when the engine speed during the automatic stop is decreasing and the pinion rotation speed and the ring gear rotation speed are synchronized. (See Patent Document 1).

  However, if it takes time for the pinion rotation speed and the ring gear rotation speed to synchronize after the start condition of the internal combustion engine is established, it takes time to cause the pinion to engage the ring gear. Therefore, it becomes difficult to restart the internal combustion engine quickly.

Japanese Patent Laying-Open No. 2005-330813 JP 2002-147325 A JP 2000-097139 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique capable of promptly restarting an internal combustion engine starter even when the internal combustion engine is stopped. .

In order to achieve the above object, the internal combustion engine starter according to the present invention employs the following means. That is, the internal combustion engine starter according to the present invention is:
A ring gear that rotates in conjunction with the crankshaft of the internal combustion engine;
A starter motor having a pinion meshing with the ring gear;
When the internal combustion engine is stopped and the engine speed is decreasing while the engine speed fluctuates, the pinion is engaged with the ring gear when the engine speed is equal to or less than the average value of the engine speed. A pinion control device that prohibits the ring gear from being engaged with the ring gear when the engine speed is higher than the average value,
It is characterized by providing.

  The internal combustion engine is stopped when a predetermined stop condition is satisfied. For example, it is assumed that the specified stop condition is satisfied when the vehicle is stopped or when the hybrid vehicle shifts from medium to high load operation to low load operation. Further, it is assumed that a specified stop condition is satisfied when the driver turns off the key switch. Then, it is restarted when a prescribed starting condition is satisfied. For example, it is assumed that a prescribed start condition is satisfied when the accelerator is depressed while the vehicle is stopped, or when the hybrid vehicle shifts from low load operation to medium to high load operation. Further, it is assumed that a prescribed start condition is satisfied when the driver turns on the key switch (when the driver is in the start position).

  If the specified start condition is satisfied while the fuel injection of the internal combustion engine is stopped and the engine speed is decreasing when the specified stop condition is satisfied, the internal combustion engine is restarted. . At this time, a rotational force is applied from the starter motor to the crankshaft of the internal combustion engine. Thus, in order to transmit the driving force from the starter motor to the crankshaft, the pinion must be engaged with the ring gear. Note that the pinion can mesh with the ring gear or be separated from the ring gear. When the internal combustion engine is in operation, the pinion and the ring gear are usually separated from each other.

  By the way, the engine speed fluctuates as the piston moves up and down, but this occurs even when the internal combustion engine is stopped. That is, during the stop of the internal combustion engine, the engine speed decreases while fluctuating. And the speed difference between the pinion and the ring gear also fluctuates due to fluctuations in the engine speed. Here, if the speed difference between the pinion and the ring gear is large, impact, noise, deterioration of durability, and the like may occur when the pinion is engaged. On the other hand, in the present invention, the pinion is engaged with the ring gear when the engine speed is equal to or lower than the average value of the engine speed. When the engine speed is higher than the average value of the engine speed, the pinion is prohibited from being engaged with the ring gear. That is, when the engine speed is less than the average value, the speed difference between the pinion and the ring gear is smaller than when the engine speed exceeds the average value, so that the pinion is engaged with the ring gear when the engine speed is less than the average value. Then, when the speed difference between the two is relatively small, the pinion can be engaged with the ring gear. As a result, the pinion can be easily bitten in the ring gear, so that biting failure can be suppressed and impact and noise can be reduced. Even if the specified start condition is not satisfied, if the pinion is engaged in the ring gear in advance, the internal combustion engine can be restarted quickly when the specified start condition is satisfied thereafter. it can.

  The average value of the engine speed can be, for example, an intermediate engine speed between a maximum value when the engine speed fluctuates and a minimum value immediately after the maximum value. The minimum value at this time may be based on estimation.

In order to achieve the above object, the internal combustion engine starter according to the present invention may employ the following means. That is, the internal combustion engine starter according to the present invention is:
A ring gear that rotates in conjunction with the crankshaft of the internal combustion engine;
A starter motor having a pinion meshing with the ring gear;
When the internal combustion engine is stopped and the engine speed is decreasing while the engine speed is fluctuating, the pinion is engaged with the ring gear when the engine speed is near the minimum value of the fluctuation of the engine speed. And a pinion control device that prohibits the ring gear from being engaged with the ring gear when the engine speed is not near the minimum value of the fluctuation,
It is good also as providing.

  As described above, while the internal combustion engine is stopped, the engine speed decreases while fluctuating. At the minimum value of the fluctuation of the engine speed, the engine speed is the lowest in the period including immediately before and immediately thereafter, and therefore the speed difference between the pinion and the ring gear is the smallest. That is, by causing the pinion to bite into the ring gear at this time, the pinion can be bitten into the ring gear at a lower rotational speed. As a result, the pinion can be easily bitten in the ring gear, so that biting failure can be suppressed and impact and noise can be reduced. For this reason, the pinion control device prohibits the pinion from being engaged with the ring gear except when the engine speed is near the minimum value of the fluctuation.

  In the present invention, the pinion control device can cause the pinion to bite into the ring gear when the internal combustion engine cannot be restarted unless power is obtained from the starter motor. .

  Even when the engine speed is decreasing when the internal combustion engine is stopped, if the engine speed is higher than the threshold value, the internal combustion engine can be restarted by restarting fuel injection. . However, when the engine speed is equal to or lower than the threshold value, the driving force of the starter motor is required to restart the internal combustion engine. That is, when the engine speed is higher than the threshold value, it is not necessary to use the starter motor, and therefore it is not necessary to cause the pinion to be engaged with the ring gear. On the other hand, when the engine speed is less than or equal to the threshold value, the driving force of the starter motor can be quickly transmitted to the ring gear by engaging the pinion with the ring gear. Here, if the pinion is engaged with the ring gear at the first minimum value after the engine speed becomes equal to or less than the threshold value, the range in which the internal combustion engine can be restarted quickly is widened. Further, when the engine speed is higher than the threshold value, the pinion is not engaged with the ring gear, so that the occurrence of impact and noise can be suppressed.

  In the present invention, the pinion control device permits or prohibits the pinion from being engaged with the ring gear when the engine speed is higher than a specified value that is not zero, and the engine speed is In the case of the specified value or less, the pinion can be allowed to be engaged with the ring gear without depending on the state of fluctuation of the engine speed.

  Here, as the engine speed decreases, the cycle of fluctuation of the engine speed becomes longer. That is, it takes a long time until the engine speed becomes less than the average value after the engine speed becomes less than the average value, or the time until the engine speed becomes the next minimum value after the engine speed becomes the minimum value. It will be long. Therefore, it is permitted or prohibited to cause the pinion to be engaged with the ring gear in accordance with the state of fluctuation of the engine speed (for example, whether it is below the average value or whether it is near the minimum value of fluctuation). If this is done, the lower the engine speed, the longer the period during which the pinion is prohibited from biting into the ring gear. In this case, even if the specified start condition is satisfied, it may take a long time to wait until the engine speed becomes equal to or less than the average value or near the minimum value of the fluctuation. is there. However, when the engine rotational speed is low, the rotational speed of the ring gear decreases, so the difference in rotational speed between the pinion and the ring gear becomes small. For this reason, when the engine speed is less than the specified value, even when the engine speed is not less than the average value or near the minimum value of the fluctuation, the impact or Noise can be reduced.

  The specified value is an upper limit value of the engine speed at which an impact, noise, or a decrease in durability when the pinion is engaged with the ring gear is within an allowable range. This specified value is a value smaller than the threshold value.

  Further, the case where the engine speed is not more than a specified value may be a case where the maximum value of the fluctuating engine speed is not more than a specified value.

That is, even if the engine speed fluctuates, the pinion may be allowed to bite into the ring gear when the fluctuation range does not exceed the specified value. Here, since the engine speed decreases while fluctuating, the next maximum value may be higher than the specified value even if the minimum value is less than or equal to the specified value. For this reason, if it takes time until the pinion bites into the ring gear after the engine speed falls below the specified value, the engine speed becomes higher than the specified value when the pinion bites into the ring gear. There is a fear. On the other hand, if the pinion is engaged with the ring gear when the maximum value of the engine speed is less than or equal to the specified value, the engine speed when the engine is engaged even if it takes time to engage is specified. It becomes as follows. That is, the pinion can be engaged with the ring gear when the engine speed is less than or equal to the specified value. The maximum value may be an actual measurement value or an estimated value. The estimated value may be predicted from the minimum value and the fluctuation range.

  Further, even if the maximum value exceeds the specified value, the pinion may be allowed to be engaged with the ring gear during the other period as long as the engine speed is equal to or less than the specified value during the other period. . Further, the pinion may be allowed to be engaged with the ring gear when the average value of the fluctuating engine speed is equal to or less than a specified value.

  In the present invention, the chamfering size of the ring gear at the position where the pinion bites into the ring gear can be made larger than that at other positions.

  Here, when the piston is at the compression top dead center, the fluctuation of the engine speed becomes a minimum value. That is, the pinion is made to bite into the ring gear when the piston reaches compression top dead center. Here, since the crank angle of the compression top dead center is unchanged, the pinion biting position in the ring gear can be specified. If the chamfering of this part is made larger than the others, the pinion can be easily bitten into the ring gear, and the biting failure can be suppressed. In other locations, the chamfering is made relatively small, so that it is possible to suppress a reduction in the strength of the ring gear and to suppress the occurrence of gear ringing. Note that the range in which chamfering is increased may be widened with some allowance. Further, the range in which chamfering is increased before and after the compression top dead center may be expanded. As a result, even when the pinion is engaged with the ring gear at an engine speed higher than the vicinity of the minimum value, the reduction in the strength of the ring gear or the occurrence of gear squealing can be suppressed. it can. Further, in a multi-cylinder engine, since the fluctuation of the engine speed becomes a minimum value at the compression top dead center of each cylinder, the position where the pinion is engaged increases. For this reason, the number of chamfered portions is increased accordingly.

The internal combustion engine starter according to the present invention is an internal combustion engine starter that automatically restarts after the internal combustion engine is automatically stopped.
A ring gear that rotates in conjunction with the crankshaft of the internal combustion engine;
A starter motor having a pinion meshing with the ring gear;
Pinion control for engaging the pinion with the ring gear when the internal combustion engine is stopped and the engine rotational speed is decreasing while the engine rotational speed is decreasing. Equipment,
It is good also as providing.

  The internal combustion engine is automatically stopped when a predetermined stop condition is satisfied. For example, it is assumed that the specified stop condition is satisfied when the vehicle is stopped or when the hybrid vehicle shifts from medium to high load operation to low load operation. Then, it is automatically restarted when a specified start condition is satisfied. For example, it is assumed that a prescribed start condition is satisfied when the accelerator is depressed while the vehicle is stopped, or when the hybrid vehicle shifts from low load operation to medium to high load operation.

  If the specified start condition is satisfied while the fuel injection of the internal combustion engine is stopped and the engine speed is decreasing when the specified stop condition is satisfied, the internal combustion engine is restarted. . At this time, a rotational force is applied from the starter motor to the crankshaft of the internal combustion engine. Thus, in order to transmit the driving force from the starter motor to the crankshaft, the pinion must be engaged with the ring gear. Note that the pinion can mesh with the ring gear or be separated from the ring gear. When the internal combustion engine is in operation, the pinion and the ring gear are usually separated from each other.

By the way, the engine speed fluctuates as the piston moves up and down, but this occurs even when the internal combustion engine is stopped. That is, during the stop of the internal combustion engine, the engine speed decreases while fluctuating. At the minimum value of this fluctuation, the speed difference between the pinion and the ring gear is the smallest because the engine speed is the lowest during the period including immediately before and after. That is, by engaging the pinion with the ring gear at this time, the engagement can be performed at a lower rotational speed. Accordingly, the pinion and the ring gear can be easily engaged with each other, so that the failure of the engagement can be suppressed and the impact and noise can be reduced.

  In the present invention, the pinion control device can mesh the pinion with the ring gear when the engine speed falls below a threshold of an engine speed at which the internal combustion engine cannot be restarted unless power is obtained from the starter motor.

  Even when the engine speed is decreasing when the internal combustion engine is stopped, if the engine speed is higher than the threshold value, the internal combustion engine can be restarted by restarting fuel injection. . However, when the engine speed is equal to or lower than the threshold value, the driving force of the starter motor is required to restart the internal combustion engine. That is, when the engine speed is higher than the threshold value, it is not necessary to use the starter motor, and therefore it is not necessary to mesh the pinion with the ring gear. On the other hand, when the engine speed is less than or equal to the threshold value, the driving force of the starter motor can be quickly transmitted to the ring gear by engaging the pinion with the ring gear. Here, if the pinion is meshed with the ring gear at the first minimum value after the engine speed becomes the threshold value or less, the range in which the internal combustion engine can be restarted quickly is widened. Further, when the engine speed is higher than the threshold value, the pinion and the ring gear are not engaged with each other, so that occurrence of impact and noise can be suppressed.

  In the present invention, the chamfering size of the ring gear at a position where the ring gear and the pinion mesh with each other can be made larger than other positions.

  Here, when the piston is at the compression top dead center, the fluctuation of the engine speed becomes a minimum value. That is, the pinion is engaged with the ring gear when the piston reaches compression top dead center. Here, since the crank angle of the compression top dead center is not changed, the meshing position of the ring gear with the pinion can be specified. If the chamfering of this part is made larger than the others, the pinion can easily engage with the ring gear, so that engagement failure can be suppressed. In other locations, the chamfering is made relatively small, so that it is possible to suppress a reduction in the strength of the ring gear and to suppress the occurrence of gear ringing. Note that the range in which chamfering is increased may be widened with some allowance. Further, in a multi-cylinder engine, the variation of the engine speed becomes a minimum value at the compression top dead center of each cylinder, so that the meshing position increases. For this reason, the number of chamfered portions is increased accordingly.

  With the internal combustion engine starter according to the present invention, the internal combustion engine can be restarted quickly even while the internal combustion engine is stopped.

It is a figure which shows schematic structure of the starting device of the internal combustion engine which concerns on an Example. It is a figure when a pinion and a ring gear have separated. It is the time chart which showed transition of the engine speed during the automatic stop of the internal combustion engine which relates to the execution example. It is the time chart which showed transition of the engine speed when the starting condition of the internal combustion engine which concerns on an Example is satisfied. It is the flowchart which showed the control flow of the pinion which concerns on an Example. 6 is an enlarged view of an outer peripheral portion of a ring gear according to Embodiment 2. FIG. It is the figure which showed the relationship between the logarithm (bitwise axis) of biting rotation speed, and the logarithm of life (vertical axis). 6 is a time chart showing a change in engine speed during stop of an internal combustion engine according to a third embodiment. 10 is a flowchart showing a control flow of a pinion according to a third embodiment.

  Hereinafter, a specific embodiment of a starting device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a starting device for an internal combustion engine according to the present embodiment. The internal combustion engine 1 shown in FIG. 1 is a water-cooled four-cycle gasoline engine having four cylinders. The internal combustion engine 1 includes a crankshaft 2 and a ring gear 3 fixed to the crankshaft 2. In the present embodiment, a gasoline engine will be described as an example, but other known engines (for example, diesel engines) can be similarly applied.

  Further, the internal combustion engine 1 is provided with a starter motor 4. The starter motor 4 is provided with a pinion 5 that meshes with the ring gear 3. The starter motor 4 is provided with an armature 6, and the central axis of the armature 6 is provided with a first output shaft 7 </ b> A. A second output shaft 7B is connected to the first output shaft 7A. The second output shaft 7B is connected to the pinion 5. The first output shaft 7A and the second output shaft 7B are connected by a spline 8. The spline 8 causes the first output shaft 7A and the second output shaft 7B to move relative to each other on the central axis. The second output shaft 7B is biased in the direction of the armature 6 by the spring 9. This is the direction in which the pinion 5 is separated from the ring gear 3. FIG. 2 is a view when the pinion 5 and the ring gear 3 are separated from each other.

  The second output shaft 7 </ b> B is operated by the solenoid 11 via the lever 10. When the solenoid 11 is energized, the lever 10 pushes the second output shaft 7B in the direction opposite to the armature 6. This is the direction in which the pinion 5 and the ring gear 3 mesh. When the energization of the solenoid 11 is stopped, the pinion 5 and the ring gear 3 are separated by the spring 9.

  In the starter motor 4 according to the present embodiment, the armature 6 and the solenoid 11 are separately supplied with current. That is, the pinion 5 can be engaged with the ring gear 3 regardless of the rotation of the armature 6.

  A clutch 12 is provided in the middle of the second output shaft 7B. The engine speed increases in a state where the pinion 5 and the ring gear 3 are engaged with each other, and the rotational speed of the second output shaft 7B driven by the internal combustion engine 1 is higher than the rotational speed of the second output shaft 7B driven by the armature 6. When becomes higher, the clutch 12 is disengaged and the transmission of power is cut off.

  The internal combustion engine 1 configured as described above is provided with an ECU 20 that is an electronic control unit for controlling the internal combustion engine 1.

  In addition to the crank position sensor 21 that detects the engine speed, various sensors are connected to the ECU 20 via electric wiring, and output signals from these various sensors are input to the ECU 20. Further, the armature 6 and the solenoid 11 are connected to the ECU 20 via electric wiring, and the ECU 20 controls these devices.

Further, the ECU 20 automatically stops the internal combustion engine 1 regardless of the driver's intention when a predetermined stop condition is satisfied. On the other hand, the ECU 20 automatically starts the internal combustion engine 1 regardless of the driver's intention when a prescribed start condition is satisfied. For example, when the vehicle stops, the internal combustion engine 1 is automatically stopped, and in this state, it is automatically started when the accelerator is depressed. Further, for example, in the case of a hybrid vehicle, the internal combustion engine 1 is automatically stopped in a low speed range that is driven by a motor, and the internal combustion engine 1 is automatically started when the vehicle shifts to a medium / high speed range.

  In this embodiment, the pinion 5 is engaged with the ring gear 3 while the engine speed is decreasing when the internal combustion engine 1 is automatically stopped. In this way, if the armature 6 is energized when the start condition is satisfied, the internal combustion engine 1 can be restarted immediately. That is, if the solenoid 11 is energized and the pinion 5 is engaged with the ring gear 3 after the start condition is established, it takes time to restart. On the other hand, the internal combustion engine 1 can be restarted promptly by previously pinching the pinion 5 into the ring gear 3.

  In this embodiment, when the engine speed decreases so that the internal combustion engine 1 cannot be restarted without the assistance of the starter motor 4, and the speed difference between the pinion 5 and the ring gear 3 is small, the pinion 5 is connected to the ring gear. 3 is bitten.

  FIG. 3 is a time chart showing the transition of the engine speed during the automatic stop of the internal combustion engine 1 according to the present embodiment. When the engine speed is higher than the threshold value, the internal combustion engine 1 can be raised by restarting the fuel injection. That is, the internal combustion engine 1 can be restarted without using the starter motor 4. In such a case, the pinion 5 and the ring gear 3 are separated from each other. However, when the engine speed is less than or equal to the threshold value, the internal combustion engine 1 cannot be restarted without the assistance of the starter motor 4.

Here, even when the internal combustion engine 1 is stopped, the engine speed varies because the pistons and valves are operating. In other words, the average value of the engine speed gradually decreases while repeating the increase and decrease. For this reason, there is a period when the engine speed starts to increase from the decrease. Here, in the compression stroke, since the piston needs energy to compress the air, the engine speed decreases. On the other hand, in the expansion stroke, since the piston is pushed by the compressed air, the engine speed increases. That is, at the compression top dead center, the engine speed turns from a decrease to an increase. Therefore, when any one of the cylinders reaches the compression top dead center, the engine speed starts to increase from the decrease. In the internal combustion engine 1 having four cylinders, the engine speed becomes a minimum value every 180 degrees in crank angle.

  At this minimum value, the speed difference between the pinion 5 and the ring gear 3 is also a minimum value. At this time, by engaging the pinion 5 with the ring gear 3, the pinion 5 is engaged with the ring gear 3. Can be made easier. Also, impact and noise can be reduced. Therefore, the ECU 20 permits the pinion 5 to be engaged with the ring gear 3 when the engine speed is near the minimum value of the fluctuation, and the pinion is other than when the engine speed is near the minimum value of the fluctuation. 5 is prohibited from being engaged with the ring gear 3.

If a pulse signal is output from the crank position sensor 21 according to this embodiment at a crank angle of, for example, every 10 degrees, the minimum value of the fluctuation of the engine speed is approximately 1
The pinion 5 can be accurately bitten into the ring gear 3 in the range from 0 deg to 10 deg.

By the way, the engine speed fluctuates even after the solenoid 11 is energized until the lever 10 pushes the second output shaft 7B in the opposite direction to the armature 6 and the pinion 5 and the ring gear 3 are actually engaged. For this reason, even if the solenoid 11 is energized when the engine speed is in the vicinity of the minimum value of the fluctuation of the engine speed, the pinion 5 may deviate from the vicinity of the minimum value when the pinion 5 is engaged with the ring gear 3. It is done. On the other hand, the instantaneous engine speed is calculated from the pulse signal from the crank position sensor 21, and the timing at which the instantaneous engine speed becomes a minimum value is predicted from the change in the instantaneous engine speed. If the solenoid 11 is energized so as to bite into the pin 3, the pinion 5 can be bitten into the ring gear 3 when the value becomes just the minimum value. That is, if the time from when the ECU 20 issues a command to energize the solenoid 11 to when the pinion 5 actually engages the ring gear 3 is assumed to be a response delay, the response delay is earlier than the timing at which the minimum value will be reached. The ECU 20 energizes the solenoid 11. Further, the timing at which the top dead center is reached in any cylinder may be predicted, and the solenoid 11 may be energized before the top dead center so that the pinion 5 is engaged with the ring gear 3 at this timing.

  Further, in preparation for the restart of the internal combustion engine 1, it is desirable that the pinion 5 is quickly engaged with the ring gear 3 when the engine speed becomes equal to or less than the threshold value. Therefore, it is desirable to cause the pinion 5 to be engaged with the ring gear 3 when the engine speed is the first minimum value that is equal to or less than the threshold value.

  If the pinion 5 is engaged in the ring gear 3 in advance as described above, the engine speed can be quickly increased by energizing the armature 6 when the start condition is satisfied while the engine speed is decreasing. Can be raised.

  FIG. 4 is a time chart showing the transition of the engine speed when the start condition of the internal combustion engine 1 according to this embodiment is satisfied. The solid line indicates the rotational speed of the internal combustion engine 1, and the alternate long and short dash line indicates the rotational speed of the starter motor 4. The rotational speed of the internal combustion engine 1 is shown as an average value. Further, the rotation speed of the starter motor 4 is a value converted into the rotation speed of the internal combustion engine 1.

  At the time indicated by A, the engine speed is a threshold value. At the time indicated by B, the meshing between the pinion 5 and the ring gear 3 is completed. That is, the pinion 5 is engaged with the ring gear 3 at the minimum value of the fluctuation of the engine speed. At the time indicated by C, the start condition is established. At this time, the armature 6 is energized. At this time, the clutch 12 is disengaged because the engine speed is high. At the time indicated by D, the rotational speed of the internal combustion engine 1 and the rotational speed of the starter motor 4 become equal. Thereby, the clutch 12 is connected. Then, after the time indicated by D, the rotation speed of the internal combustion engine 1 is increased by the starter motor 4, so that the internal combustion engine 1 is restarted.

  FIG. 5 is a flowchart showing a control flow of the pinion 5 according to the present embodiment. This routine is repeatedly executed after the stop condition of the internal combustion engine 1 is established and the stop operation is started or during the stop operation.

  In step S101, it is determined whether the engine speed is equal to or less than a threshold value. That is, it is determined whether or not the vehicle cannot be restarted without assistance from the starter motor 4. If an affirmative determination is made in step S101, the process proceeds to step S102, whereas if a negative determination is made, this routine is temporarily terminated.

  In step S102, it is determined whether or not the engine speed is a minimum value. That is, it is determined whether or not it is time to cause the pinion 5 to bite into the ring gear 3. For example, it is determined that the minimum value is obtained when the inter-engine speed changes from a decrease to an increase. If an affirmative determination is made in step S102, the process proceeds to step S103, whereas if a negative determination is made, this routine is temporarily terminated.

In step S103, a command to cause the pinion 5 to be engaged with the ring gear 3 is issued. That is, the solenoid 11 is energized. In this embodiment, the ECU 20 that executes step S103 corresponds to the pinion control device according to the present invention.

  In step S104, it is determined whether a starting condition for the internal combustion engine 1 is satisfied. If an affirmative determination is made in step S104, the process proceeds to step S105, whereas if a negative determination is made, this routine is temporarily terminated.

  In step S105, the armature 6 is energized. That is, the internal combustion engine 1 is restarted.

  In this embodiment, the internal combustion engine 1 is automatically stopped regardless of the driver's intention when the prescribed stop condition is satisfied, and the internal combustion engine 1 is automatically activated regardless of the driver's intention when the prescribed start condition is satisfied. In the case where the key switch is turned off by the driver's intention, the key switch is turned on by the driver's intention while the engine speed is decreasing. Can be applied similarly. On the contrary, when the internal combustion engine 1 is stopped by the driver, that is, when it is not an automatic stop, the pinion 5 does not have to be engaged with the ring gear 3.

  Further, in this embodiment, the pinion 5 is allowed to be engaged with the ring gear 3 when the engine speed is close to the minimum value of fluctuation, and other than when the engine speed is near the minimum value of fluctuation. Then, it is prohibited to cause the pinion 5 to bite into the ring gear 3. This is intended to cause the pinion 5 to be engaged with the ring gear 3 when the rotational speed difference between the pinion 5 and the ring gear 3 is the smallest. On the other hand, the time for allowing the pinion 5 to bite into the ring gear 3 may be further expanded. That is, when the internal combustion engine 1 is stopped and the engine speed is decreasing while the engine speed is changing, the pinion 5 is engaged with the ring gear 3 when the engine speed is equal to or less than the average value of the engine speed. It is possible to allow the pinion 5 to be engaged, and to prohibit the pinion 5 from being engaged with the ring gear 3 when the engine speed is higher than the average value. That is, when the engine speed is equal to or lower than the average value, the difference in speed between the pinion 5 and the ring gear 3 is relatively smaller than when the engine speed is higher than the average value. Moreover, the pinion 5 can be engaged with the ring gear 3 in a wider range when the average value or less is set, rather than the minimum value. As a result, it is possible to provide more opportunities for the pinion 5 to be engaged with the ring gear 3 while suppressing an impact or the like when the pinion 5 is engaged with the ring gear 3.

  Note that the average value of the engine speed can be a value corresponding to an intermediate value between the maximum value and the minimum value immediately thereafter. Moreover, it is good also as a value equivalent to the intermediate value of the minimum value and the maximum value immediately after that. Furthermore, it is good also as an average value in a regular period.

  Further, in consideration of the above-described response delay, the ECU 20 may issue a command to energize the solenoid 11 at a time earlier than the timing at which the engine speed is less than the average value by the response delay.

  In this way, the internal combustion engine 1 can be restarted quickly, and the occurrence of impact and noise can be suppressed.

  In this embodiment, the shape of the ring gear 3 is different. Others are the same as those in the first embodiment, and thus the description thereof is omitted.

  FIG. 6 is an enlarged view of the outer peripheral portion of the ring gear 3 according to the present embodiment. A solid line indicates a case where the chamfer is large, and a broken line indicates a case where the chamfer is small.

  Here, the outer peripheral portion of the ring gear 3 on the pinion 5 side is chamfered. The chamfering of the ring gear 3 in the present embodiment is performed over the entire circumference of the ring gear 3, but the chamfering of the first contact portion when the pinion 5 bites is made larger than the other.

Here, since it is the compression top dead center that the engine speed becomes a minimum value, the first contact point of the pinion 5 with the ring gear 3 is every 180 degrees in crank angle. That is, the four-cylinder internal combustion engine 1 has two locations on the ring gear 3 and can be specified.

  In this way, by increasing the chamfering of the ring gear 3, the pinion 5 can be easily engaged with the ring gear 3. Thereby, the impact and noise at the time of biting can be reduced.

  Moreover, since the chamfering of other parts is relatively small, it is possible to suppress the strength of the ring gear 3 from being lowered. Furthermore, occurrence of gear ringing can also be suppressed.

  Note that the range in which chamfering is increased may be widened with some allowance. In this case, the range in which chamfering is increased before and after the top dead center may be expanded. For example, the chamfer may be increased by the pulse width of the crank position sensor 21 before and after the top dead center. Further, when the pinion 5 is engaged with the ring gear 3 at an engine speed higher than the vicinity of the minimum value, the chamfer may be increased in accordance with the range.

  In this embodiment, the pinion 5 is engaged with the ring gear 3 when the engine speed is decreasing when the internal combustion engine 1 is stopped and the starting condition is satisfied. Thereafter, the armature 6 is energized to restart the internal combustion engine 1. In other words, the pinion 5 is not meshed with the ring gear 3 in advance, but the solenoid 11 is energized after the start condition is established, so that the pinion 5 is meshed with the ring gear 3 and then the armature 6 is energized.

  If the engine start speed is satisfied when the engine speed is equal to or less than the specified value, the pinion 5 is immediately turned on regardless of whether the engine speed fluctuates, that is, whether the fluctuation is a minimum value or not. Is engaged with the ring gear 3. On the other hand, if the starting condition is satisfied when the engine speed is higher than the specified value, the pinion 5 is engaged with the ring gear 3 when the subsequent engine speed is the minimum value of fluctuation. That is, when the start condition of the internal combustion engine 1 is satisfied, the timing at which the pinion 5 is engaged with the ring gear 3 is changed according to the engine speed at that time. Others are the same as those in the first embodiment, and thus the description thereof is omitted.

  In general, the impact force is proportional to the energy of an object. Further, in the steel used for the pinion 5 and the like, the relationship between the logarithm of stress and the logarithm of life is a linear relationship having a negative gradient as shown in FIG. Here, FIG. 7 is a diagram showing the relationship between the logarithm of the rotational speed of rotation (horizontal axis) and the logarithm of the lifetime (vertical axis). The biting speed is the rotation speed of the ring gear 3 when the pinion 5 bites into the ring gear 3 (that is, the engine speed), and the logarithm of the biting speed is correlated with the logarithm of stress.

  Since the biting speed is proportional to the square root of the rotational energy, if the biting speed is low, the service life of the pinion 5, the ring gear 3, etc. is dramatically improved. Therefore, in this embodiment, if the engine speed is low to some extent, the pinion 5 is allowed to be engaged with the ring gear 3 regardless of the fluctuation state of the engine speed.

If it is always prohibited to allow the pinion 5 to be engaged with the ring gear 3 when the engine speed is other than the minimum value of fluctuation, when the engine speed is low, it takes time until the next minimum value is reached. End up. For example, in the four-cylinder four-cycle internal combustion engine 1 according to the present embodiment, the engine speed becomes the minimum value of fluctuation when any cylinder reaches the top dead center (TDC). That is, the minimum value is obtained every crank angle of 180 deg. The time required to rotate the crank angle 180 deg is inversely proportional to the engine speed. For this reason, even if the specified starting condition is satisfied, it takes time until the engine speed reaches the next minimum value, and during that time, it is prohibited to cause the pinion 5 to be engaged with the ring gear 3, so immediately. The internal combustion engine 1 cannot be started. If it does so, there exists a possibility that it may become difficult to complete restart of the internal combustion engine 1 rapidly.

  On the other hand, when the engine speed is equal to or less than the specified value, the pinion 5 is engaged with the ring gear 3 regardless of whether or not the engine speed is a minimum value of fluctuation. That is, the pinion 5 is bitten into the ring gear 3 without waiting for the local minimum value. The specified value here varies depending on the design conditions, material, and the like of the starter motor 4, and is determined beforehand by experiment or the like as a value (allowable value) within which the life, noise, impact, etc. are within the allowable range. The specified value is a value larger than zero. In other words, the pinion 5 is not included in the ring gear 3 only when the internal combustion engine 1 is completely stopped and the engine speed becomes zero.

  FIG. 8 is a time chart showing the transition of the engine speed when the internal combustion engine 1 according to this embodiment is stopped. The threshold value is the same as that described in FIG. The specified value according to the present embodiment is a value lower than the threshold shown in FIG.

  By the way, while the internal combustion engine 1 is stopped, the engine speed decreases while fluctuating, so that even if the engine speed once falls below a specified value, it increases thereafter and becomes higher than the specified value. There is. That is, the specified value may be crossed between the minimum value and the next maximum value. For example, a certain amount of time is required until the pinion 5 is engaged with the ring gear 3 after the engine speed is detected and the engine speed is determined to be equal to or less than a specified value. That is, there is a response difference. Then, even when the engine speed is detected to be equal to or less than a specified value when the engine speed is detected, the engine speed may be higher than the specified value when the pinion 5 is engaged with the ring gear 3. If it does so, there exists a possibility that noise, an impact, etc. may generate | occur | produce or durability may fall.

  On the other hand, for example, if the pinion 5 is engaged with the ring gear 3 only when the maximum value when the engine speed fluctuates is estimated to be equal to or less than a specified value, the specified value is obtained even if the engine speed fluctuates. The pinion 5 can be engaged with the ring gear 3 at the following times. The maximum value is the engine speed when the engine speed changes from increasing to decreasing. Further, for example, the pinion 5 may be engaged with the ring gear 3 only when it is estimated that the average value of the engine speed is equal to or less than a specified value.

  For example, the fluctuation of the engine speed is mainly caused by the force received from the cylinder pressure. Therefore, the fluctuation range of the engine speed can be estimated from the cylinder pressure. Further, for example, the intake air amount in the cylinder can be calculated from the pressure in the intake manifold, and the pressure in the cylinder can be estimated thermodynamically from the intake air amount, the crank angle, the compression ratio, and the like. That is, the fluctuation range of the engine speed can be easily estimated from the pressure in the intake manifold. Then, the maximum value can be estimated from the minimum value and the fluctuation range. The relationship between the pressure in the cylinder and the fluctuation range of the engine speed may be obtained in advance by experiments or the like. Note that the pressure in the cylinder may be directly measured by a sensor. Also, the next minimum value can be predicted from the maximum value and the fluctuation range. Thereby, the timing which makes the pinion 5 bit in the ring gear 3 can be determined. Similarly, the average value of the engine speed can be predicted.

  Then, the fluctuation range of the engine speed is estimated from the pressure in the intake manifold, and the pinion 5 is connected to the ring gear 3 when it is determined that the value obtained by adding the fluctuation range to the minimum value of the fluctuation of the engine speed is equal to or less than the specified value. Bite into.

  FIG. 9 is a flowchart showing a control flow of the pinion 5 according to the present embodiment. This routine is repeatedly executed after the stop condition of the internal combustion engine 1 is established and the stop operation is started or during the stop operation. In addition, the same code | symbol is attached | subjected about the step in which the same process as the flow shown in FIG. 5 is performed, and description is abbreviate | omitted.

  In step S201, it is determined whether the engine speed is equal to or less than a specified value. That is, it is determined whether the impact and noise are within the allowable range even when the pinion 5 is engaged with the ring gear 3. If an affirmative determination is made in step S201, the process proceeds to step S102, whereas if a negative determination is made, this routine is temporarily terminated. And when affirmation determination is made by step S102, it progresses to step S202.

  In step S202, the fluctuation range of the engine speed is estimated. The fluctuation range of the engine speed is estimated based on the pressure in the intake manifold. At this time, the maximum value of the fluctuation of the engine speed may be predicted.

  In step S203, it is determined whether or not the maximum value of fluctuations in the engine speed is equal to or less than a specified value. That is, it is determined whether or not the value obtained by adding the fluctuation range to the minimum value of the engine speed obtained in step S102 is equal to or less than a specified value. If an affirmative determination is made in step S203, the process proceeds to step S103 where the pinion 5 is engaged with the ring gear 3. On the other hand, if a negative determination is made, the engine speed may be higher than the specified value when the pinion 5 is engaged with the ring gear 3, so this routine is temporarily terminated.

  In this embodiment, the pinion 5 is engaged with the ring gear 3 when the maximum value of the engine speed is equal to or less than the specified value. However, when the engine speed is equal to or less than the specified value, the pinion 5 is simply connected to the ring gear. 3 may be bitten. Further, in this embodiment, the maximum value of the engine speed is predicted, but an actual measurement value by the crank position sensor 21 may be used. That is, if the maximum value of the engine speed fluctuation obtained by the crank position sensor 21 is equal to or less than the specified value, it is considered that the engine speed does not exceed the specified value even if the engine speed subsequently fluctuates. May be bitten into the ring gear 3.

  As described above, according to this embodiment, when the engine speed is higher than the specified value, the pinion 5 is engaged with the ring gear 3 when the engine speed is the minimum value of fluctuation. Impact and noise when biting can be reduced. In addition, when the engine speed is equal to or less than the specified value, the pinion 5 is engaged with the ring gear 3 even if the engine speed is other than the minimum value of fluctuation, so that quick engagement is possible. At this time, since the engine speed is low, generation of noise and impact can be suppressed.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Crankshaft 3 Ring gear 4 Starter motor 5 Pinion 6 Armature 7A 1st output shaft 7B 2nd output shaft 8 Spline 9 Spring 10 Lever 11 Solenoid 12 Clutch 20 ECU
21 Crank position sensor

Claims (6)

A ring gear that rotates in conjunction with the crankshaft of the internal combustion engine;
A starter motor having a pinion meshing with the ring gear;
When the internal combustion engine is stopped and the engine speed is decreasing while the engine speed fluctuates, the pinion is engaged with the ring gear when the engine speed is equal to or less than the average value of the engine speed. A pinion control device that prohibits the ring gear from being engaged with the ring gear when the engine speed is higher than the average value,
A starter for an internal combustion engine comprising: A ring gear that rotates in conjunction with the crankshaft of the internal combustion engine;
A starter motor having a pinion meshing with the ring gear;
When the internal combustion engine is stopped and the engine speed is decreasing while the engine speed is fluctuating, the pinion is engaged with the ring gear when the engine speed is near the minimum value of the fluctuation of the engine speed. And a pinion control device that prohibits the ring gear from being engaged with the ring gear when the engine speed is not near the minimum value of the fluctuation,
A starter for an internal combustion engine comprising:   2. The pinion control device causes the ring gear to be engaged with the ring gear when the engine speed falls below a threshold of an engine speed at which the internal combustion engine cannot be restarted unless power is obtained from the starter motor. Or a starting device for an internal combustion engine according to 2;   The pinion control device permits or prohibits the pinion from being engaged with the ring gear when the engine speed is higher than a specified value that is not zero, and the engine speed is equal to or less than the specified value. 4. The internal combustion engine according to claim 1, wherein the pinion is allowed to be engaged with the ring gear without depending on a state of fluctuation of the engine speed. 5. Starting device.   5. The internal combustion engine starter according to claim 4, wherein the engine speed is equal to or less than a specified value when the maximum value of the fluctuating engine speed is equal to or less than a specified value.   6. The starter for an internal combustion engine according to claim 1, wherein a chamfer size of the ring gear at a position where the pinion engages with the ring gear is made larger than that at other positions. .

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