The present invention relates to a vehicle control device, and particularly to a control device of an idle-stop vehicle that performs stop and restart of an engine automatically.
Recently, vehicle technology for the purpose of saving energy resources and preserving an environment has been developed. For example, there is a vehicle on which an idle stop system of cutting fuel supplied to an engine and removing torque generated by the engine when a predetermined condition (automatic stop condition) is established during operation is mounted. The automatic stop condition of the engine is established, for example, when a driver releases the foot from an accelerator or steps on the brake. Subsequently, the engine restarts at a point of time when a restart request from the driver is generated, or when the operation of the engine becomes necessary.
As a method of restarting the engine, there is adopted a method of using a starter of a pinion extrusion type to extrude a pinion of the starter to a ring gear side of the engine and engage the pinion with the ring gear, transmitting rotation of the starter to the engine, rotating the engine, and starting the engine.
For example, PTL 1 proposes a method of quickening recovery of rotation of the engine by starting to supply power to a motor of the starter and rotating the pinion when a condition such as stepping on the accelerator is established during inertial rotation after the torque generated by the engine is removed and a restart request is generated, engaging the pinion with the ring gear at a point of time when a rotation speed of the pinion is synchronized with a rotation speed of the ring gear, and starting cranking by the starter. PTL 1 discloses predicting a future rotation speed of the engine by operating kinetic energy of the engine and an amount of work that disturbs motion of the engine, and predicting future kinetic energy.
PTL 1: JP-A-2005-330813
When the automatic stop condition of the engine is established and subsequently the pinion of the starter is engaged in advance with the ring gear during a period of the inertial rotation after the torque generated by the engine is removed, it is desirable to engage the pinion with the ring gear at almost a zero rotation speed of the engine in order to reduce the bite-in sound as much as possible. However, when the restart request from the driver is generated, there exists a request for restarting the engine as quickly as possible. It is desirable to engage the pinion in advance with the ring gear at a high rotation speed of the engine in order to prepare for this request. Meanwhile, the starter of the pinion extrusion type has delay time until the pinion is extruded and arrives at the ring gear, and it is necessary to predict the rotation speed of the engine at a point of time when the pinion arrives at the ring gear at extrusion timing of the pinion.
During the period of the inertial rotation of the engine, the rotation speed of the engine increases and decreases repetitively and decreases pulsatively. For this reason, in order to engage the pinion with the ring gear during the period of the inertial rotation of the engine, it is necessary to predict the rotation speed of the engine decreasing pulsatively and engage the pinion with the ring gear at any rotation speed of the engine satisfying both suppression of the bite-in sound and the preparation for the restart request.
Here, in a rotation sensor of an electromagnetic pickup type used generally for detecting the engine rotation number, an output interval of the sensor increases in a region where the rotation speed of the ring gear is low, due to resolution limited by a tooth interval of pulsars. In this case, in the method described in PTL 1, there is a problem in starter operation timing such as engagement of the pinion that cannot be controlled in a period in which an output of a crank angle sensor is not updated.
The present invention has been made to solve the above problems and a main object thereof is to carry out a starter operation command at optimal timing, even in a region of an engine rotation number where an output interval of a rotation sensor with respect to the engine rotation number is long.
In order to achieve the above object, provided is a vehicle control device of the present invention including: an automatic stop unit which automatically stops an engine on the basis of an operating state of a vehicle; an automatic start unit which controls a starter during a period until the engine completely stops after the automatic stop unit executes the automatic stop of the engine, and restarts the engine; and an engine rotation detection unit which detects or estimates a crank phase or a rotation number of the engine, wherein the automatic start unit determines a control command of the starter at an interval shorter than an update interval of a signal of the engine rotation detection unit.
According to the present invention, starter operation determination or control is executed at an interval shorter than a signal interval of an engine rotation sensor, in a region of any engine rotation number. For this reason, a starter operation command can be carried out at optimal timing.
An embodiment of a vehicle control device according to the present invention will be described hereinafter with reference to
A ring gear 2 is attached to the crank shaft 1a of the internal-combustion engine body 1. The starter body 3 is provided with an actuator 5 driven by the semiconductor switching element 13, a motor 7, and a pinion gear 4. A pulse sensor 37 that detects unevenness of the ring gear 2 and converts the detected unevenness into a pulse signal is provided in the vicinity of the ring gear 2. The ECU 11 calculates a rotation number of the engine 1 (engine rotation number) on the basis of the pulse signal output from the pulse sensor 37.
The starter body 3 includes the pinion gear 4, the actuator 5, a lever 6, the starter motor 7, and a pinion pulse sensor 38. The pinion gear 4 is a gear that can engage with the ring gear 2, and is provided to be movable in an axial direction to a shaft (pinion shaft) 8 of the starter motor 7. The actuator 5 is an electric actuator for moving the pinion gear 4 in the axial direction of the pinion shaft 8 via the lever 6. The starter motor 7 is a motor for cranking the engine 1 as described below. The pinion pulse sensor 38 is a sensor for detecting a rotation speed of the pinion shaft 8.
When a pinion transfer command of the ECU 11 is input to a gate terminal of a semiconductor switching element 13a for pinion transfer actuator drive, power of a battery 12 is supplied to the actuator 5. Accordingly, since the actuator 5 moves the pinion gear 4 in a rightward direction as shown via the lever 6, the pinion gear 4 engages with the ring gear 2.
When a motor drive command from the ECU 11 is input to a gate terminal of a semiconductor switching element 13b for starter motor drive, the power of the battery 12 is supplied to the starter motor 7. Accordingly, the starter motor 7 rotates the crank shaft 1a via the pinion gear 4 and the ring gear 2 and cranks the engine 1.
Note that a transmission 16 is connected to the crank shaft 1a. The transmission 16 transmits rotation drive force generated in the internal-combustion engine body 1 to a road surface via a drive shaft 17 and a tier 18. In addition, a vehicle speed sensor 33 which detects a rotation pulse of an output shaft of the transmission 16 is attached to the transmission 16. The ECU 11 performs conversion by a predetermined coefficient, on the basis of an output signal from the vehicle speed sensor 33, and calculates a vehicle speed value.
A battery sensor 39 is connected to a minus terminal side of the battery 12. The battery sensor 39 detects a battery voltage, a battery current, and an ambient temperature of the battery, and outputs the detected information to the ECU 11.
An accelerator opening sensor 230 which detects a stepping-in amount of an accelerator pedal (not shown) of the vehicle, a throttle opening sensor 231 which detects an opening degree of a throttle valve (not shown), an air flow sensor 232 which measures an amount of air sucked into cylinders of the engine 1, a vehicle speed sensor 233 which detects a travel speed of the vehicle, a brake switch 234 which detects an operation of a foot brake (not shown), a cam angle sensor 235 and a crank angle sensor 2366 which detect a cam angle signal and a crank angle signal used for calculation of ignition and injection timing and cylinder determination of the engine 1, the above-described ring gear sensor 237 and pinion gear sensor 238, and a battery sensor 239 which detects the battery voltage, the battery current, and the ambient temperature of the battery and outputs information are connected to an input circuit 224 of the ECU 11.
An operation processing device 223 executes an operation process according to a predetermined program read from a ROM 241. The operation processing device 223 gives a command to an output circuit 226 on the basis of an output from the input circuit 224, data read from a RAM 242, reception data from another control device obtained via a communication driver 240, and the like. The ignition coil 14a, the fuel injection valve 15, and the semiconductor switching element 213 are connected to the output circuit 226. When the ignition coil 14a receives an ignition signal output from the output circuit 226 on the basis of ignition timing calculated by the operation processing device 223 from signals of the cam angle sensor 235 and the crank angle sensor 2366, the ignition coil 14a supplies power of a high voltage to the ignition plug 14b in order to ignite an air-fuel mixture inside the cylinders by the ignition coil 14a. When the fuel injection valve 15 receives a valve opening signal output via the output circuit 226 at predetermined timing for predetermined time, the fuel injection valve 15 injects fuel. Note that the ECU 11 calculates an amount of fuel to be injected by the fuel injection valve 15 from an amount of air sucked measured by the air flow sensor 232.
When the semiconductor switching element 213 receives a PWM drive signal output via the output circuit 26, the semiconductor switching element 213 drives the actuator 5 and the starter motor 7. The switching element 213a drives the actuator 5 and the switching element 213b drives the starter motor 7. Note that when the ECU 11 receives a drive request for the starter 3, the ECU 11 outputs the PWM drive signal via the output circuit 226.
When a predetermined deceleration-mode fuel cut condition is satisfied, the deceleration-mode fuel cut control unit 311c controls the fuel injection valve 15 so as to stop supplying of the fuel to the engine 1 during deceleration of the vehicle. In a case where the engine rotation number is equal to or less than a fuel injection recovery rotation number when supplying of the fuel to the engine 1 is stopped by the deceleration-mode fuel cut control unit 311c, the fuel injection recovery control unit 311d controls the fuel injection valve 15 so as to resume supplying of the fuel to the engine 1.
When a predetermined coast stop condition including at least one condition where a vehicle speed is equal to or less than a coast stop permission vehicle speed, the coast stop control unit 311e controls the fuel injection valve 15 so as to stop supplying of the fuel to the engine 1.
The pinion gear 4 is movable in an axial direction of the starter motor 7. The pinion gear 4 engages with the ring gear 2 connected to the crank shaft of the engine and rotates. Accordingly, the pinion gear 4 can transmit power to the engine. The one-way clutch 4207 transmits power only in a direction in which the starter motor 7 rotates the engine forward. Accordingly, when the one-way clutch 4207 engages with the pinion gear 4 and the ring gear 2, a rotation speed of the ring gear becomes a synchronous speed with respect to a rotation speed of the starter motor 7 according to a deceleration ratio or becomes a rotation speed higher than the rotation speed of the starter motor 7. That is, when the rotation speed of the ring gear 2 is about to become lower than the rotation speed of the pinion gear 44, the one-way clutch 4207 transmits power. For this reason, the rotation speed of the ring gear 2 does not become lower than the synchronous speed with respect to the starter motor 77. Meanwhile, when the rotation speed of the ring gear is higher than the synchronous speed, the one-way clutch does not transmit power. For this reason, the power is not transmitted from the ring gear 2 to the side of the starter motor 77.
As illustrated in
Incidentally, the restart after the automatic stop of the engine 11 is desirably carried out as quickly as possible upon a restart request. In addition, when the pinion gear 4 is engaged with the ring gear 2, there is a risk that a bite-in sound of the pinion gear 4 and the ring gear 2 is generated to give unpleasant feeling to a driver. Therefore, in this embodiment, in order to restart the engine 11 quickly and suppress the bite-in sound of the pinion gear 4 and the ring gear 2, engagement of the pinion gear 4 and the ring gear 2 is carried out during an inertial rotation period of the engine 1 after the automatic stop of the engine, at the restart after the automatic stop of the engine.
Specifically, when there is the automatic stop request of the engine 1, the fuel injection and the ignition are stopped upon the stop request. Accordingly, the engine 1 rotates inertially. In the period of the inertial rotation, an ON signal is output to the switch 13a for supplying power to the magnet switch, and supplying of power to the coil 5 starts. Accordingly, the pinion gear 4 is extruded to the side of the ring gear 2 in an axial direction of the rotation shaft of the pinion gear and the pinion gear 4 engages with the ring gear 2 before the engine 1 completely stops (in the period of the inertial rotation). When there is the engine restart request under the engagement state, an ON signal is output to the drive relay 206a and supplying of power to the motor 11 starts. Accordingly, the pinion gear 4 is driven to rotate, and the ring gear 2 is driven to rotate by the rotation of the pinion gear 4. Accordingly, cranking is performed.
Here, it is necessary to engage the pinion gear 4 and the ring gear 2 immediately before the inertial rotation of the engine 1 stops, specifically, in a region where a relative rotation speed of the ring gear 2 with respect to the pinion gear 4 is in a predetermined extremely-low rotation speed range (for example, 0±100 rpm), in order to reduce the bite-in sound as much as possible. Particularly, when the engine rotation speed is zero, an effect of suppressing the sound is high.
Meanwhile, in a rotation sensor of an electromagnetic pickup type used as the crank angle sensor 236 in this embodiment, there is a limitation in the engine rotation speed at which an NE signal can be output, and there is a case where the engine rotation speed in an extremely low rotation speed region (for example, a region of 200 to 300 rpm or less) cannot be calculated with high precision. This is because a passage signal of a tooth portion (protrusion 26) cannot detect the engine rotation number in predetermined operation time in the rotation sensor, in the region where the engine rotation speed is extremely low. However, a rotation speed region where the bite-in sound of the pinion gear 4 and the ring gear 2 can be suitably suppressed is included in a rotation speed region that cannot be calculated from the NE signal. For this reason, there is a risk that drive control of the pinion gear 4 cannot be carried out appropriately at an engine rotation speed calculated on the basis of the NE signal. That is, the engagement of the pinion gear 4 and the ring gear 2 cannot be carried out at optimal timing. As a result, there is a risk that the bite-in sound increases.
Therefore, in this embodiment, in the period of the inertial rotation after the automatic stop of the engine 1, a rotation orbit of the inertial rotation of the engine is predicted on the basis of the engine rotation speed calculated on the basis of the NE signal. Then, engagement timing of the pinion gear 4 and the ring gear 2 is controlled on the basis of the predicted rotation orbit. Specifically, in the prediction of the rotation orbit, an instant rotation speed is calculated on the basis of the NE signal and the above-described rotation orbit is predicted on the basis of the rotation speed including a plurality of instant rotation speeds in a period in which the instant rotation speed tends to decrease.
Here, the instant rotation speed means a value calculated from time necessary for the crank shaft 1a to rotate at a predetermined rotation angle (in this embodiment, 30° CA), every time the crank shaft 1a rotates in such a manner.
Hereinafter, control of the engagement timing of the pinion gear 4 and the ring gear 2 will be described in detail with reference to
During deceleration travel until the vehicle stops, for the purpose of improvement of deceleration feeling and reduction of a fuel consumption amount, when a predetermined condition (deceleration-mode fuel cut condition) is established in step 5101, drive of the fuel injection valve 15 is stopped in step 5102. Accordingly, cutting of supplying of the fuel to the engine 1 (fuel cut) is executed and the engine brake is operated. Note that an example of the deceleration-mode fuel cut condition includes a condition that “a vehicle speed is 20 km/h or more, an engine rotation number is 1200 rpm or more, and an accelerator pedal (not shown) is not stepped on.”
During the above-described execution of the deceleration-mode fuel cut, when the engine rotation number decreases to a predetermined rotation number (fuel injection recovery rotation number (for example, 1100 rpm)) to resume (recover) the fuel injection and the fuel injection recovery condition is established in step 5103, a fuel recovery process of resuming (recovering) the fuel injection is executed in a sub-routine of step 104. The sub-routine of the fuel recovery process will be described below.
At the time when a throttle opening is fully closed and the engine 1 runs under no load after the execution of the fuel recovery process in step 5104, when each input condition of the vehicle speed sensor 33, the brake switch 34 or the like satisfies the coast stop condition in step S105, drive of the fuel injection valve 15 is stopped and cutting of fuel supply of the engine 1 (fuel cut) is performed in step 5106. Note that an example of the coast stop condition includes a condition that “a vehicle speed is 14 km/h or less and a brake pedal (not shown) is stepped on.”
The above-described fuel cut operation gradually decreases the engine rotation number. When the engine rotation number is equal to or less than a predetermined value A of a determination condition (for example, the engine rotation number is 600 rpm) in step 5107, the process proceeds to step 5108. A previous pinion rotation operation, that is, an operation of supplying power to the starter motor 7, increasing a pinion gear rotation number calculated from the pinion gear sensor 38 to a predetermined value, and stopping supplying of power is performed.
In this case, the above-described previous pinion rotation operation gradually decreases the pinion gear rotation number by inertia over time. Meanwhile, since the engine rotation number decreases pulsatively while suction→compression→expansion→exhaust is repeated, synchronization timing of the engine rotation number calculated from the ring gear sensor 37 and the pinion gear rotation number decreasing gradually by the previous pinion rotation operation is predicted. When a pre-mesh condition is established in step 5109, the process proceeds to step 5110. Pinion gear transfer is executed, that is, a so-called pre-mesh state in which supplying of power to the starter motor 7 and the actuator 5 starts and the rotating pinion gear 4 is engaged with the ring gear 2 via the lever 6 is achieved. Note that an example of the pre-mesh condition includes a condition that “a difference between the rotation number of the pinion gear 4 when it is assumed that the pinion gear 4 is completely synchronized with the ring gear 2 and the actual rotation number of the pinion gear 4 is within ±100 rpm.”
When it is determined in step 5111 that there is no restart request from the driver such as release of the foot from the brake pedal (not shown), that is, so-called change of mind, the process proceeds to step 5112. The above-described pre-mesh state is maintained, and the internal-combustion engine body 1 is completely stopped. The process proceeds to step 5113 and a waiting state is maintained until the restart request is received.
When the restart request is received due to an operation of the driver in the waiting state in step 5113, the process proceeds to step 5116. Power is supplied to the starter motor 7, the fuel injection is resumed, and the internal-combustion engine is restarted.
In addition, when it is determined in step 5111 that there is the change-of-mind request from the driver, the process proceeds to step 5114 and it is determined whether the engine rotation number is equal to or less than a predetermined value B (for example, the engine rotation number is 600 rpm). When the engine rotation number is more than the predetermined value B, the process proceeds to step 5116 and when the internal-combustion engine rotation number is equal to or less than the predetermined value B, the process proceeds to step 5115. After drive of the starter body 3 is prohibited for predetermined time, the process proceeds to step 5116.
Subsequently, the process proceeds to step 5117 and it is determined whether the engine rotation number is equal to or more than a predetermined value C (for example, the engine rotation number is 500 rpm). When the engine rotation number is equal to or more than the predetermined value C, the process proceeds to step 5118 and drive of the starter body 3 is turned off.
As described above, since time until the pinion gear 4 engages with the ring gear 2 can be shortened by performing the pre-mesh operation of the rotation number synchronous type of the pinion gear 4 and the ring gear 2, noise generated at the time of the gear engagement can be reduced. In addition, since an operation of engaging the pinion gear 4 with the ring gear 2 becomes unnecessary at the time of next restart, start time until the internal-combustion engine is completely exploded after the restart request is received can be shortened.
In response to a restart request generated after the pinion gear 4 engages with the ring gear 2, the restart is performed immediately by the starter in step 6309. Since the pinion gear 4 is engaged, immediate supply of power to the starter motor 7 and start of cranking make quick restart possible. Meanwhile, there is a possibility that the restart request be generated before the pinion gear 4 engages after the idle stop starts. In response to such a possibility, the determination of the restart request is made in steps 6302 and 6305, and the fuel injection is resumed in step 6310 to attempt the restart by combustion. In a region where the idle stop condition is established and the engine rotation number is high even after the fuel cut, the engine rotation can be recovered by resuming the fuel injection and resuming combustion. However, in a region where the engine rotation number is low, the engine may stop without recovery of the engine rotation even though the combustion is resumed. In step 6311, it is determined whether the combustion recovery of the engine has succeeded. Only when the combustion recovery has not succeeded, the pinion gear 4 is engaged with the ring gear 2 and the restart is performed by the starter motor 7 in step 6312. In the combustion recovery determination, at a point of time when the engine rotation speed is less than a predetermined value (for example, 50 r/min), it can be determined that the combustion recovery has not succeeded. In addition, at a point of time when the engine rotation speed is more than a predetermined value (for example, 500 r/min), it can be assumed that the combustion recovery is completed.
Next, a problem in the related art and an outline of a countermeasure for the problem will be described with reference to
For this reason, as a countermeasure, in a region of a low engine rotation number in particular, a phase change of the crank shaft at a point of time of the prediction start is calculated on the basis of information of a previous crank signal, according to timing of the engine rotation number operation (crank phase operation). Accordingly, the engine rotation number and the crank phase in a period in which the crank signal is not updated are calculated. In this way, the future engine rotation number can be predicted with high precision by complementing signal information in the period in which the crank signal is not updated, and the pinion gear 4 can be engaged with the ring gear 2 without generating the abnormal sound by reducing a difference between the rotation number of the ring gear and the pinion gear (for example, ΔNe≦50 r/min).
Next, a method of predicting the future rotation speed of the ring gear 2 will be described with reference to
The phase change of the engine rotation speed changes periodically according to the crank angle and is obtained as a change rate of the engine rotation speed using the crank angle as a parameter.
Note that this example is an example of a three-cylinder engine and the crank angle has zero degree in a place where a cylinder in a compression stroke reaches a top dead center (TDC). In a four-cycle engine, since the crank shaft has one cycle by two rounds, a different cylinder has the same phase every time the crank shaft rotates by 240 degrees, in the case of the three-cylinder engine. For this reason, the rotation speed of the engine is accelerated and decelerated periodically every time the crank shaft rotates by 240 degrees.
In addition, in the case of the four-cylinder engine, since the rotation speed of the engine is accelerated and decelerated periodically every time the crank shaft 1a rotates by 180 degrees, a function in
Next, an outline of a future engine rotation number prediction unit will be described with reference to
When the method of predicting the engine rotation speed is used, the future engine rotation speed at any time can be predicted. In addition, since it can be assumed that the rotation speed of the pinion gear 4 during the inertial rotation after the previous rotation decreases at constant deceleration as with the steady change of the ring gear 2, the future rotation speed of the pinion gear 4 can be predicted in a linear relation. Therefore, a future rotation speed difference between the ring gear 2 and the pinion gear 4 can be predicted by combining the future rotation number prediction of both the ring gear 2 and the pinion gear 4.
Next, a future rotation number prediction technique of the ring gear 2 will be described in detail with reference to
A crank phase complement unit 1002 adds a crank phase change of the minute time to a previous crank phase last operated on the basis of a signal of the crank angle sensor 236 and corresponding to the initial condition, and complements a crank phase in the period in which the signal of the crank angle sensor 236 cannot be obtained. For the crank phase change, a signal of either the crank angle sensor 236 or the ring gear sensor 237 may be used, but information of the crank angle sensor 236 having higher resolution is desirably used. A phase change operation unit 1003 uses crank phase information complemented by the crank phase complement unit 1002 to apply an angular acceleration change depending on the crank phase to the engine rotation number, and calculates a phase change affecting the engine rotation number until predetermined time such as the delay time of the pinion extrusion unit passes. For example, the angular acceleration until the predetermined time passes may be differentiated on the basis of the relation of the crank phase and the angular acceleration in
A steady change operation unit 1004 operates, for example, an inclination when it is assumed that the engine rotation number decreases at constant deceleration, from engine rotation numbers previously operated a plurality of times on the basis of the ring gear sensor 237, and calculates a steady change affecting an engine rotation number until the delay time of the pinion extrusion unit passes.
A starter control unit 1005 controls an operation of the starter motor 7 on the basis of an engine rotation number after the delay time of the pinion extrusion unit passes, which is predicted from the engine rotation number acquired from the engine rotation number complement unit 1001, the phase changes of the engine rotation number acquired from the phase change operation unit 1003 and the steady change of the engine rotation number acquired from the steady change operation unit 1004. Examples of the control of the operation of the starter include executing determination of power supply start (previous rotation before engagement) timing, power supply end timing, pinion extrusion timing by the actuator 5, and power supply start timing of the starter motor 7 after the engagement of the ring gear 2 and the pinion gear 4, or permission/prohibition determination of the above-described control.
A process illustrated in
Note that the process illustrated in
In addition, the engine rotation number complement unit 1001 and the crank phase complement unit 1002 do not need to perform the complement on the basis of the signals of the crank angle sensor 236 and the ring gear sensor 237, and the complement of the period in which the signal is not updated may be performed on the basis of information previously acquired from the phase change operation unit 1003 or the steady change operation unit 1004.
In addition, the process illustrated in
In this way, in step 304 or step 307 in
Next, an example of the process illustrated in
In
Note that instead of the process of step 1204, it may be determined whether the engine rotation number is lower than a predetermined region. For example, it is anticipated that when a last-operated engine rotation number is low, the signal interval of the crank angle sensor 236 increases. For this reason, only in this case, the engine rotation number complement unit 1001 or the crank phase complement unit 1002 can be executed.
In the following step 1207, extrusion timing of the pinion gear 4 by the actuator 5 is operated on the basis of the operation result of the engine rotation number described in
In step 1208, it is determined whether timing is the extrusion timing tp2 of the pinion gear 4. At a point of time when the timing is the extrusion timing tp2, the process proceeds to step 1209. The switch 13a for supplying power to the magnet switch is turned on, and supplying of power to the actuator 5 starts. Accordingly, the pinion gear 4 is extruded to the ring gear 2 and the pinion gear 4 and the ring gear 2 engage.
Note that in a period including the extrusion timing tp2 operated in step 1208, the extrusion timing tp2 may be updated again, for example by confirming the update of the signal of the crank angle sensor 236 and adopting an update value or executing the process in step 1206 again. Accordingly, when the signal of the crank angle sensor 236 or the like is updated after the extrusion timing of the pinion gear is operated and more accurate future rotation number information can be operated, the future rotation number information can be updated and the extrusion timing tp2 can be updated again.
Note that the example of the operation of the extrusion timing tp2 of the pinion gear 4 is illustrated in
Note that as illustrated in step 5108 in
According to this embodiment described in detail above, the following excellent effects can be obtained.
During the inertial rotation after the automatic stop of the engine, a complement value of a detection signal of the crank angle sensor 236 is used to predict an engine rotation speed in a rotation region that cannot be calculated from the detection signal and control such as engagement of the pinion gear 4 and the ring gear 2 is carried out at a desired engine rotation speed within a region of the prediction result. For this reason, for example, the engagement of the pinion gear 4 and the ring gear 2 can be carried out at optimal timing and then the bite-in sound upon the engagement of the pinion gear 4 and the ring gear 2 can be suppressed. Further, when the instant rotation speeds NES reaches a period TDW in which the speed decreases monotonously to zero, the plurality of instant rotation speeds NES is used to predict the rotation orbit in the period TDW. For this reason, this configuration is suitable for accurately predicting the rotation orbit at the speed close to zero without increasing the engine rotation speed. In addition, at this time, the instant rotation speeds NES within the period TDW in which the speed decreases monotonously or in a period as close as to the period TDW is used to predict the rotation orbit. For this reason, a prediction system of the rotation orbit can be improved.
In addition, in the rotation sensor such as the crank angle sensor 236 and the ring gear sensor 237, a pulse signal interval increases in the low rotation speed region and the engine rotation speed cannot be calculated at predetermined operation timing. Since the rotation orbit in the extremely low rotation speed region is complemented, the control of, for example, the engagement of the pinion gear 4 and the ring gear 2 can be carried out at optimal timing even in the extremely low rotation speed region.
In addition, timing at which the actual engine rotation speed becomes zero is estimated on the basis of the predicted rotation orbit, and the engagement process of the pinion gear 4 is carried out at the estimated timing or timing close to the estimated timing. For this reason, this configuration is significant for suppressing the engagement of the pinion gear 4 and the ring gear 2. In addition, the above-described engagement can be carried out at the timing at which the speed first becomes zero by the inertial rotation after the automatic stop of the engine. As a result, the pinion and the ring gear can engage at time as early as possible. That is, this configuration is suitable for reliably completing the engagement of the pinion and the ring gear before a next engine restart request.
In addition, the extrusion timing tp2 of the pinion gear 4 is determined on the basis of the predicted rotation orbit and the extrusion operation time TA necessary for the extrusion operation of the pinion gear 4. For this reason, the engagement of the pinion gear 4 and the ring gear 2 can be performed at appropriate timing.
In addition,
When the engine rotation number is a negative value, that is, when the pinion gear 4 and the ring gear 2 engage in a situation in which the swing-over of the engine 1 is generated, and the starter motor 7 is driven to rotate, force in a backward rotation direction is transmitted to the starter motor 7 and a failure of the starter motor 7 or an increase of consumption power occurs. For this reason, when the engine rotation number is the negative value, the starter control unit 1005 prohibits an operation of the starter motor 7. Here, the swing-over of the engine 1 is not necessarily generated when the engine 1 stops and may also be generated at a time interval shorter than the signal interval of the crank angle sensor 236. It has been very difficult to detect the generation of the swing-over when the crank signal interval is long.
In the present invention, the interval of the crank angle signals is also complemented in the region of the low engine rotation number and the starter operation is executed at an interval shorter than the interval of the crank angle signals, on the basis of the complement information. For this reason, even though, for example, the driver steps on the brake pedal immediately before the engine stops (timing at which the crank signal interval increases) and the engine restart request is generated at any timing, the swing-over of the engine 1 can be detected and the operation command of the starter can be changed.
As described above, the present invention relates to an engine stop/start control device that has an automatic stop/start function of automatically stopping an engine when a predetermined automatic stop condition is established, starting cranking by a starter when a predetermined restart condition is subsequently established, and restarting the engine, carries out cranking at restart of the engine in a state in which a pinion of the starter engages with a ring gear connected to an output shaft of the engine, and releases the engagement after the cranking ends. Particularly, the invention described in the claims includes a rotation speed calculation unit which calculates an engine rotation speed on the basis of a detection signal of a rotation sensor which detects rotation of the output shaft, a prediction unit which predicts a rotation orbit of inertial rotation of the engine on the basis of the engine rotation speed calculated by the rotation speed calculation unit in a period in which the engine inertially rotates after the automatic stop of the engine, and a control unit which controls engagement timing of the pinion and the ring gear on the basis of the rotation orbit predicted by the prediction unit.
In short, in the idle stop control, the pinion needs to be engaged with the ring gear during the inertial rotation of the engine after the automatic stop of the engine. In this case, in order to suppress the bite-in sound of the pinion and the ring gear, the engagement is desirably carried out in a predetermined engine rotation speed region (extremely low rotation speed region) in which an effect of suppressing the sound is high. However, in the rotation sensor which detects the rotation of the engine output shaft, there is a limitation in an engine rotation speed at which a detection signal can be output, and there is a case where the engine rotation speed in the extremely low rotation speed region cannot be calculated with high precision. In this case, the engagement of the pinion and the ring gear cannot be carried out at optimal timing and there is a risk that the bite-in sound increases.
In view of the above-described point, in the present invention, during the inertial rotation after the automatic stop of the engine, a calculation value based on a detection signal of the rotation sensor is used to predict the engine rotation speed in the region that cannot be calculated from the detection signal. In addition, drive of the pinion is controlled such that the above-described engagement is carried out at a desired engine rotation speed within a region of the prediction result. Accordingly, the engagement of the pinion and the ring gear can be carried out at the optimal timing and then the bite-in sound upon the engagement of the pinion and the ring gear can be suppressed.
In addition, the rotation speed calculation unit calculates an instant rotation speed serving as the engine rotation speed calculated from time necessary for rotation at a predetermined rotation angle of the output shaft, and the prediction unit predicts the rotation orbit on the basis of a plurality of instant rotation speeds in a period in which the instant rotation speed tends to decrease. The instant rotation speed increases and decrease repetitively. However, in the period in which the instant rotation speed tends to decrease, inclination of the engine rotation speed toward the speed of zero, that is, the rotation orbit toward the speed of zero can be predicted. Here, the instant rotation speed used for the prediction of the rotation orbit only needs to include at least the plurality of instant rotation speeds in the period in which the instant rotation speed tends to decrease, and the rotation orbit may be predicted only by the instant rotation speeds in the above-described period, or instant rotation speeds immediately before the above-described period (for example, instant rotation speeds in a period in which the instant rotation speed tends to increase) may be added and the rotation speed may be predicted.
Number | Date | Country | Kind |
---|---|---|---|
2013-063197 | Mar 2013 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2014/052824 | 2/7/2014 | WO | 00 |