JP2013047466A - Engine automatic restart device of idling stop vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly crank an engine using a starter before a stop of the engine, when a restart requirement of the engine is detected by a complete stop of the engine after an engine automatic stop.SOLUTION: The engine is automatically stopped when a predetermined idling stop condition is satisfied, and if the restart requirement of the engine is detected during the engine automatic stop, the engine is cranked by the starter to be restarted. If the restart requirement of the engine is detected before an engine speed is stopped accompanied by the engine automatic stop, a process proceeds from a step S13 to a step S15 or later, a termination period of a reverse rotation period when the engine reversely rotates is detected, and the engine is started to be cranked by the starter when the termination period of the reverse rotation period is detected.

Description

  The present invention relates to an idle stop vehicle that performs automatic stop and automatic restart of an engine, and more particularly to control at the time of automatic engine restart by a starter.

  As described in Patent Document 1, in an idle stop vehicle, when a predetermined idle stop condition is satisfied, for example, when a driver temporarily stops the vehicle while waiting for a signal, fuel consumption saving or exhaust emission is reduced. In order to reduce the engine, the engine is automatically stopped, and then the engine is cranked by the starter when an automatic engine restart request is detected, such as when the driver starts the vehicle. Thus, the engine is automatically restarted. In general, a starter rotates a pinion with a motor, and pushes the pinion and meshes with a ring gear connected to a crankshaft of the engine to crank the engine.

JP 2010-236533 A

Immediately before engine rotation stops due to automatic engine stop, engine rotation may stop after alternately repeating reverse rotation and forward rotation of the engine. If the engine restart request is detected and the pinion is engaged with the ring gear during the swinging period, the pinion collides with the ring gear during the reverse rotation of the engine (the reverse rotation of the ring gear), and the pinion is excessive. In addition, there is a possibility that the starter may be deteriorated in durability due to an impact, and a large noise is generated.
Therefore, in Patent Document 1, when the engine rotation speed drops to a predetermined rotation speed immediately before becoming 0 during the engine rotation drop period, the pinion is engaged with the ring gear by the actuator, and then an engine restart request is generated. Sometimes, a pinion is rotated by a motor, cranking by a starter is started, and the engine is restarted. In this way, the pinion is prevented from meshing with the ring gear during the engine swing period.

  However, in this case, it is necessary to provide a starter that can independently operate the motor that rotationally drives the pinion and the actuator that moves forward to mesh the pinion with the ring gear on the engine side. It will be complicated. Further, such a technique is adopted for a vehicle using a starter having a simple structure in which a pinion is pushed out in mesh with a ring gear mechanically interlocked with the operation of a motor, such as a known magnet shift type starter. I can't.

  The present invention has been made in view of such circumstances, and without using a starter that can independently operate the motor and the actuator independently, before the engine rotation stops with the automatic engine stop. Provided is a novel engine automatic restart device for an idle stop vehicle capable of smoothly performing automatic engine restart without waiting for engine rotation to stop when an automatic engine restart request is detected. The purpose is that.

  The engine automatic restart device for an idle stop vehicle according to the present invention automatically stops the engine when a predetermined idle stop condition is satisfied, and detects the engine restart request during the engine automatic stop. The engine is automatically restarted by cranking. Then, before the engine rotation stops with the automatic stop of the engine, the end timing of the reverse rotation period in which the engine rotates in the reverse direction is determined, and before the engine rotation stops with the automatic engine stop. When the engine restart request is detected, if it is determined that the reverse rotation period has ended, cranking of the engine by the starter is started.

According to the present invention, when it is determined that the reverse rotation period has ended, the cranking of the engine by the starter is started, so that the pinion can be prevented from meshing with the ring gear during the reverse rotation period. Cranking with a starter can be performed smoothly without degrading durability. In addition, the above-described effects can be realized with a simple or configuration that does not require the use of a starter that can independently operate the motor and the actuator independently.

The block diagram which shows simply the system configuration | structure of the engine automatic restart apparatus of the idle stop vehicle which concerns on one Example of this invention. The block diagram which shows the starter system of the said Example. The characteristic view which shows the change of the engine speed immediately after an engine automatic stop. The flowchart which shows the flow of control at the time of the engine automatic restart which concerns on the said Example. The characteristic view which shows the relationship between the crank position of the compression cylinder at the time of reverse rotation generation | occurrence | production, and a reverse rotation period. Explanatory drawing for demonstrating the relationship between the crank position of the compression cylinder at the time of reverse rotation generation | occurrence | production, and a reverse rotation period.

  Hereinafter, the present invention will be described with reference to illustrated embodiments. FIG. 1 shows a system configuration of an automatic engine restart device for an idle stop vehicle according to an embodiment of the present invention. The vehicle is provided with an engine 1 that outputs a vehicle driving force by combustion, and a continuously variable transmission 5 that transmits the output of the engine 1 to wheels. The starter (starter motor) 6 rotates the crankshaft when the engine is started, that is, performs cranking, and a pinion (pinion gear) 7 is provided at the tip of the output shaft of the starter 6. The configuration of the starter 6 will be described later.

  A drive plate 2 that rotates integrally with the crankshaft 12 is provided at the end of the crankshaft 12 of the engine 1. A ring gear 2 a that can engage with the pinion 7 of the starter 6 is provided on the outer periphery of the drive plate 2. Is provided. A battery 10 is mounted as a drive source for on-vehicle electrical components such as the starter 6.

  An alternator 3 for charging the battery 10 is installed in the vicinity of the front portion (vehicle traveling direction side) of the engine 1. A belt 9 is wound around a motor pulley 11 provided at the front end of the shaft of the alternator 3 and a crank pulley 8 provided at the front end of the crankshaft 12 of the engine 1, and the alternator is passed through the crank pulley 8 and the belt 9. 3 is driven by the engine 1. The operations of the starter 6 and the alternator 3 are controlled by a control unit (ECU) 4. The ECU 4 is connected to a crank angle sensor 13 as a crank angle detecting means for detecting the rotational position of the crankshaft, and the engine rotation speed is obtained using a detection signal of the crank angle sensor 13.

  In addition, this vehicle performs a so-called idle stop that temporarily stops the engine when a predetermined idle stop condition is satisfied during vehicle operation, and detects an engine restart request in this idle stop state. This is a so-called idle stop vehicle that automatically restarts the engine. In this way, at the time of starting the engine 1 including when the engine is restarted from the idle stop and when the engine is started for the first time, the pinion 7 is engaged with the ring gear 2a and the starter 6 rotates the crankshaft 12 of the engine 1. The engine 1 is started by driving, so-called cranking.

  Next, the configuration of the starter 6 will be described with reference to FIG. Reference numeral 28 denotes a starter switch that is ON / OFF controlled by a signal from the ECU 4. The starter 6 is driven when the starter switch 28 is turned on. The starter 6 is provided with a pinion 7 that can slide on the shaft 29 and an overrun clutch 27 that blocks transmission of rotation from the pinion 7 to the shaft 29 when the rotational speed becomes excessively high.

  One end of a shift lever 24 that can rotate about a fulcrum 25 is rotatably connected to the pinion 7, and the pinion 7 slides on the shaft 29 as the shift lever 24 rotates. The other end of the shift lever 24 is rotatably connected to a plunger 23 that penetrates the two coils of the pull-in coil 21 and the holding coil 22.

  The driving of the starter 6 configured as described above will be described. First, when the starter switch 28 is turned ON, the current from the battery 10 is supplied to the pull-in coil 21 and the holding coil 22 and grounded. By this energization, a magnetic force is generated in both the coils 21 and 22, and the plunger 23 is attracted to the pull-in coil 21 by this magnetic force. At this time, the shift lever 24 connected to the plunger 23 rotates to the right in FIG. 2 so as to be drawn around the fulcrum 25, and the pinion 7 connected to the other end of the shift lever 24 is in the direction of the shaft tip of the starter 6 (see FIG. 2) and is engaged with the ring gear 2a.

  Further, when the plunger 23 is attracted to the pull-in coil 21 and pulled to the right side in FIG. 2, the plunger 23 comes into contact with the main contact 26 and turns on the main contact 26. As a result, the starter 6 starts rotating when the current from the battery 10 is energized, and cranks the engine 1 via the ring gear 2a. During cranking, the position of the plunger 23 is fixed by the magnetic force of the holding coil 22, and when the starter switch 28 is turned off, the energization to the holding coil 22 is cut off. 2 is returned to the left side in FIG. 2, the shift lever 24 is rotated leftward in FIG. 2, and the pinion 7 is pulled to the right side in FIG. 2, and the engagement with the ring gear 2a is released.

  The structure of the starter is not limited to that of the illustrated embodiment, and various known starters can be used as long as the pinion that is rotationally driven at the time of start moves and meshes with the ring gear. .

  As shown in FIG. 3, when the engine is automatically stopped, after an engine rotation drop period D1 in which the engine rotation speed Ne drops from the engine stop start time t1 to the time t2 when the engine rotation speed Ne first becomes 0 (zero), the engine rotation speed is decreased. Until the engine rotation is stably zero and the engine rotation is completely stopped, a phenomenon may occur in which the rotation direction of the engine is reversed by the compression pressure of the cylinder in the compression stroke. That is, before the engine rotation is completely stopped, an engine rotation swing period D2 in which the reverse rotation and the normal rotation of the engine are repeated may be passed.

  Here, when an engine restart request is detected during the engine rotation descent period D1 or the engine rotation swing period D2 before the engine rotation is completely stopped when the engine is automatically stopped by idle stop. If cranking of the engine 1 is performed by the starter 6 during the reverse rotation periods D3 and D5 in which the engine rotates in the reverse direction within the engine rotation swing period D2, the pinion 7 collides with the ring gear 2a. There is a risk of causing noise and reducing the durability of the starter. Further, even during the engine rotation drop period D1, if the cranking of the engine 1 is performed by the starter 6 immediately after the engine stop start time t1, the rotational speed difference between the pinion 7 and the ring gear 2a is large. There is a risk of causing noise and reducing the durability of the starter.

  Therefore, in this embodiment, when the engine restart request is detected before the engine rotation is completely stopped due to the idle stop, it is determined that the reverse rotation period in which the engine rotates in reverse is finished. The engine is cranked by a starter.

  FIG. 4 is a flowchart showing a flow of restart control of the engine 1 from such an automatic stop (idle stop) state of the engine.

  This routine is executed by the ECU 4 in step S11 on condition that the engine is automatically stopped. In step S12, it is determined whether an engine restart request due to a driver (driver) start operation has been detected. Specifically, it is assumed that when the idle stop switch is turned on by a brake pedal depressing operation or an accelerator pedal depressing operation, an engine restart request accompanying a start operation by the driver's intention is detected, step S12. In step S125, the restart request flag A by the driver operation is set to 1, and the process proceeds to step S13. The restart request flag A by the driver operation is reset to 0 when the engine is started by the starter drive.

  In step S13, it is determined based on the engine rotation speed detected by the crank angle sensor 13 or the like whether or not the engine rotation is completely stopped. If the engine rotation has completely stopped, the process proceeds to step S14.

  If it is during the engine rotation descent period D1 or the engine rotation swing period D2 before the engine rotation is completely stopped, the process proceeds from step S13 to step S15, and it is determined whether the engine is reversed from normal rotation to reverse rotation. judge. To detect the reverse rotation from the normal rotation to the reverse rotation, for example, the crank angle sensor 13 that can detect the angular position of the crankshaft is used. It is possible to detect inversion.

  When the reverse rotation from the normal rotation to the reverse rotation is detected, the process proceeds from step S15 to step S16, the measurement timer for the reverse rotation period D3 is activated, and the measurement of the reverse rotation period D3 is started. In step S17, it is determined whether the reverse rotation period D3 measured by the timer has passed a predetermined time ΔT. If the predetermined time ΔT has elapsed, it is determined that the end time t3 of the reverse rotation period D3 is reached, that is, it is determined that the reverse rotation period D3 is switched to the normal rotation period D4, and the process proceeds to step S19.

  If the reverse rotation period D3 has not passed the predetermined time ΔT, the process proceeds from step S17 to step S18, and it is determined whether the engine has reversed from reverse rotation to normal rotation. The reverse rotation from the reverse rotation to the normal rotation can be detected using the crank angle sensor 13 in the same manner as the detection of the reverse rotation from the normal rotation to the reverse rotation.

  If the reverse rotation from the reverse rotation to the normal rotation is detected before the predetermined time ΔT elapses, the process proceeds from step S18 to step S19. In step S19, when the restart request flag A by the driver operation is 1, the process proceeds to step S20, and cranking by the starter 6 is started. That is, when the engine automatic restart request accompanying the vehicle start operation by the driver is detected before the engine rotation is completely stopped due to the automatic engine stop, the reverse rotation period D3 has passed the predetermined time ΔT. If the reverse rotation from the reverse rotation to the normal rotation is detected, it is determined that the reverse rotation period D3 is switched to the normal rotation period D4, and cranking by the starter 6 is started.

If the engine restart request accompanying the driver's operation is not detected in step S12, the process proceeds to step S21 to determine whether an engine restart request other than the driver's operation is detected. As an example of a restart request other than the driver's operation, in this embodiment, it is determined whether the battery charge amount has dropped below a predetermined value. If it is determined that the battery charge amount has dropped below the predetermined value, the process proceeds to step S22, the restart request flag B other than by a driver operation is set to 1, and the process proceeds to step S13. Note that the restart request flag B other than the driver operation is reset to 0 when the engine is started by the starter drive.
If it is determined in step S13 that the engine rotation has completely stopped, the process proceeds to step S14. If the restart request flag B other than the driver's operation is 1, the process proceeds to step S23, and cranking of the engine by the starter is started. .

  Such characteristic configurations and operational effects of this embodiment will be listed.

  [1] If an engine restart request is detected before the engine is completely stopped with the automatic stop of the engine, the cranking of the engine 1 by the starter 6 is temporarily performed during the engine rotation drop period D1 or the engine reverse rotation period D3. However, in this embodiment, cranking of the engine 1 by the starter 6 is started after the reverse rotation period D3 is finished. For this reason, the engine can be automatically restarted smoothly without causing noise during the engagement and without causing a decrease in the durability of the starter.

  [2] In steps S16 and S17, it is determined that the reverse rotation period D3 of the engine 1 has ended when a predetermined period ΔT has elapsed since the start of the reverse rotation of the engine 1 has been detected. By setting the predetermined period ΔT to an appropriate value by adaptation in advance, the end timing t3 of the reverse rotation period D3 can be accurately obtained with a simple control configuration.

  [3] Preferably, in order to increase the detection accuracy of the end timing t3 of the reverse rotation period D3, the predetermined time ΔT is adjusted according to the angular position of the crankshaft at the start timing of reverse rotation of the engine. The angular position of the crankshaft at this time can be obtained from the detection signal of the crank angle sensor 13 described above.

  The reverse rotation period D3 changes according to the crank position of the cylinder in the compression stroke when reverse rotation occurs. 5 and 6, when reverse rotation occurs, the crankshaft rotates in the reverse rotation direction as indicated by arrow Y1 in FIG. 6 due to the compression reaction force in the compression stroke cylinder. After the reverse rotation occurs, when the cylinder in the expansion stroke is returned to the top dead center side from the exhaust valve opening timing (EVO), the in-cylinder air is compressed and becomes a reaction force in the forward direction. As shown, the crankshaft is pushed back in the forward rotation direction again. Here, as the compression stroke cylinder at the time of reverse rotation is closer to the top dead center (TDC), the compression reaction force in the reverse rotation direction is larger and is pushed back greatly in the reverse direction. Thus, the time from the start of reverse rotation to the end of reverse rotation, that is, the reverse rotation period D3 becomes longer. On the other hand, since the compression reaction force in the reverse rotation direction is smaller as the compression stroke cylinder at the time of reverse rotation is farther from the top dead center (TDC), the reverse rotation period is shortened as shown in the region α2 in FIG.

  Therefore, the closer the crank position of the compression stroke cylinder when reverse rotation occurs to the top dead center (TDC), the longer the predetermined period ΔT corresponding to the reverse rotation period is set, and the crank position of the compression stroke cylinder when reverse rotation occurs becomes longer. By setting the predetermined period ΔT corresponding to the reverse rotation period to be shorter as it is farther from the TDC, the end time t3 of the reverse rotation period can be obtained with high accuracy according to the crank angle position when the reverse rotation occurs.

  [4] Further, in this embodiment, in addition to the end timing t3 of the reverse rotation period D3 using the predetermined period ΔT, in step S18, the strength of the signal level of the crank angle sensor 13 is used to change from the reverse rotation to the normal rotation. Reversal to rotation is detected.

  [5] When the reverse rotation from the reverse rotation to the normal rotation is detected by the sensor as described above, the detection timing is inevitably delayed from the actual end timing t3, and the cranking start timing is actually reversed. A delay is likely to occur with respect to the rotation end timing t3. Therefore, in the present embodiment, in combination with the determination process based on the reverse rotation period (ΔT) in steps S16 and S17, when the reverse rotation from the reverse rotation to the normal rotation is detected before the predetermined time ΔT elapses, at that time. The cranking of the engine 1 by the starter 6 is started. That is, cranking by the starter 6 is started when the predetermined period ΔT elapses or when reversal is detected, whereby the cranking start timing of the starter 6 is sufficiently set to the actual reverse rotation end timing t3. You can get closer.

  [6] The determination process of the end time t3 of the reverse rotation period is not limited to that in the above-described embodiment. For example, the reverse rotation period ends when the engine rotation speed becomes a predetermined value or less during the reverse rotation of the engine. And start cranking by the starter. Then, even if an engine restart request is detected during the engine rotation swing period D2 after the reverse rotation period D3, the end of the reverse rotation period D5 can be determined, and cranking by the starter during the reverse rotation period is performed. Can be avoided.

  [7] Furthermore, in this embodiment, when an automatic engine restart request accompanying a vehicle start operation by the driver is detected, as described above, cranking by the starter 6 is started after the reverse rotation period ends. This suppresses / avoids the impression that the engine restart responsiveness is low. Conversely, if a request for automatic restart of the engine other than the vehicle start operation by the driver, such as a decrease in battery charge, is detected, the starter starts cranking after confirming that the engine has completely stopped. doing. In other words, in the case of a restart request other than the driver's operation, the engine restart should be performed smoothly and reliably rather than the response of the restart, compared to the engine restart request accompanying the driver's operation. Therefore, the restart before the engine is completely stopped is prohibited, and the engine is restarted after confirming that the engine has completely stopped. This makes it possible to restart the engine more reliably and smoothly.

  In this embodiment, it is determined that the engine rotation is completely stopped when the engine rotation speed is stably zero. However, if the engine rotation speed is continuously close to zero, the engine is completely stopped. It may be determined that it has stopped.

DESCRIPTION OF SYMBOLS 1 ... Engine 4 ... Control unit (ECU)
6 ... Starter 10 ... Battery

Claims (6)

An engine of an idle stop vehicle that automatically stops the engine when a predetermined idle stop condition is satisfied, and restarts the engine by cranking the engine with a starter when an engine restart request is detected during the engine automatic stop. In the automatic restart device,
Determination means for determining an end timing of a reverse rotation period in which the engine rotates in the reverse direction before the engine rotation stops due to the automatic stop of the engine;
When the engine restart request is detected before the engine rotation is stopped due to the automatic stop of the engine, if it is determined that the reverse rotation period has ended, the engine automatic restart that starts the cranking of the engine by the starter is started. Starting means;
An engine automatic restart device for an idle stop vehicle characterized by comprising:   2. The idle according to claim 1, wherein the determination unit determines that the reverse rotation period has ended when a predetermined period of time has elapsed after detecting the start of reverse rotation of the engine. Automatic engine restart device for stop vehicles. Crank angle detecting means for detecting the angular position of the crankshaft;
Adjusting means for adjusting the predetermined time according to the angular position of the crankshaft at the start of reverse rotation of the engine;
The engine automatic restart device for an idle stop vehicle according to claim 2. Reversal detecting means for detecting whether the engine is reversed from reverse rotation to normal rotation based on the engine rotation speed;
The engine automatic restarting means determines that the reverse rotation period has ended when the reverse rotation from the reverse rotation to the normal rotation is detected before the predetermined time has elapsed, and cranks the engine by the starter. The engine automatic restart device for an idle stop vehicle according to claim 2 or 3, wherein   The determination means determines that the reverse rotation period has ended when the engine rotation speed becomes equal to or lower than a predetermined value during engine reverse rotation, and starts cranking of the engine by a starter. Item 5. An automatic engine restart device for an idle stop vehicle according to any one of Items 1 to 4. When the engine automatic restart means detects an engine automatic restart request accompanying a vehicle start operation by the driver, the engine automatic restart means performs cranking by a starter when the engine automatic restart means determines that the reverse rotation period has ended. Start,
The cranking by the starter is started after confirming that the engine has stopped when detecting an automatic engine restart request other than the vehicle start operation by the driver. The engine automatic restart device for an idle stop vehicle according to any one of claims 5 to 6.

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