JP6203653B2 - Control device for idle stop system - Google Patents

Description

  The present invention relates to a control device for an idle stop system that automatically stops and restarts an engine.

  In recent years, automobile technologies aimed at saving energy resources and protecting the environment have been developed. For example, there is a vehicle equipped with an idle stop system that stops fuel supplied to an engine and loses torque generated by the engine when a predetermined condition (automatic stop condition) is satisfied during operation. The engine automatic stop condition is satisfied when the driver removes his or her foot from the accelerator or steps on the brake.

  In this idle stop system, even if the vehicle is not stopped, the engine is automatically stopped when the engine automatic stop condition is satisfied. Thereafter, when a request for restarting the engine (restart request) occurs during the engine inertia rotation period until the crankshaft of the engine stops rotating, it is required to restart the engine as soon as possible. The restart request is, for example, that the driver removes his foot from the brake pedal.

  As a technique for satisfying this requirement, for example, when a restart request is generated during an engine inertia rotation period immediately after an idle stop request is generated, the fuel that has been stopped is supplied again to the engine, so that the combustion recovery is resumed. A technique for starting is mentioned. Here, depending on the state of the engine, if the combustion is not performed well and it is difficult to restart the combustion, it is determined by the starter based on the rotation speed of the ring gear when the first cylinder to which fuel is supplied again is after the expansion stroke. As start assist, starter assist restart is performed by driving the starter (see, for example, Patent Document 1).

Patent No. 5094889

  Due to the above background, in an idle stop system, when a restart request is generated during an engine inertia rotation period immediately after the occurrence of an idle stop request, it is required to restart the engine as soon as possible. However, in the above conventional idle stop system, when the restart is requested, the fuel is supplied to the engine by the combustion return, so that the engine speed increases and the engine ring gear speed is synchronized with the starter pinion. Therefore, it may be difficult to quickly engage the pinion gear in the ring gear. As a result, it may take a long time to restart the engine with the assistance of the starter.

  The present invention has been made in view of the above points, and the object of the present invention is to promptly restart the engine with a starter when an engine restart request is generated after an idle stop. An object of the present invention is to provide a control device for an idle stop system.

  In order to solve the above-described problem, the control device for the idle stop system according to the present invention supplies fuel to the engine when the engine restart is requested during engine inertia after the fuel supply is stopped, and the starter It is determined whether or not to assist the restart of the engine by the motor, and at least a part of the period from the determination that the engine restart assist is performed until the ring gear is engaged with the pinion gear, The engine speed is reduced, the ring gear is engaged with the pinion gear, and the starter motor is driven to assist the engine restart.

  According to the present invention, when an engine restart request is generated after an idle stop, the engine can be restarted promptly.

It is the schematic diagram which showed the apparatus structure and circuit connection state of the idle stop system which concern on 1st Embodiment of this invention. It is a control block diagram of the control apparatus which controls the idle stop system which concerns on 1st Embodiment of this invention. It is a flowchart of the control apparatus shown in FIG. FIG. 4 is a flowchart showing a continuation of the flow shown in FIG. 3. It is the figure which showed the timing chart of the idle stop system shown in FIG. It is a flowchart of the control apparatus of the idle stop system which concerns on 2nd Embodiment. 7 is a flowchart showing a continuation of the flow shown in FIG. 6. It is the figure which showed the timing chart of the idle stop system which concerns on 2nd Embodiment. It is a flowchart of the control apparatus of the idle stop system which concerns on 3rd Embodiment. 10 is a flowchart showing a continuation of the flow shown in FIG. 9. It is the figure which showed the timing chart of the idle stop system which concerns on 3rd Embodiment.

The present invention will be described by the following three embodiments.
[First Embodiment]
FIG. 1 is a schematic diagram showing a device configuration and a circuit connection state of an idle stop system 1 according to the first embodiment of the present invention. In this embodiment, the idle stop system 1 includes an engine (not shown) whose crankshaft rotates by supplying fuel, a starter 101 that assists in starting the engine, and a control device 108 that controls the starter 101 and the engine. And.

  The starter 101 according to the present embodiment is a so-called pinion extrusion type starter. Specifically, a starter motor 105 that assists engine start, a pinion gear 103 that is rotationally driven by the starter motor 105, and a pinion gear 103 are provided. And a magnet switch 102 for pushing out.

  The rotation of the starter motor 105 is decelerated by a reduction mechanism inside the starter motor 105. As a result, the torque of the starter motor 105 is increased and transmitted to the pinion gear 103. The starter motor 105 has a structure in which when the magnet switch 102 is energized, the pinion gear 103 is pushed out (right direction in FIG. 1) and is engaged with the ring gear 104. Here, the ring gear 104 is synchronized with the rotation of the crankshaft of the engine and is attached to the crankshaft. In addition, as long as it has the function to push out the pinion gear 103, it is not limited to a magnet switch like this embodiment.

  The pinion gear 103 is integrated with the one-way clutch 107. As described above, the pinion gear 103 has a structure that can move in the axial direction of the starter motor 105 by energizing the magnet switch 102 from the control device 108. The pinion gear 103 can transmit power to the engine by meshing with the ring gear 104 connected to the crankshaft of the engine and rotating.

  The one-way clutch 107 is configured such that power is transmitted only in the direction in which the starter motor 105 rotates the engine forward. As a result, when the pinion gear 103 is engaged with the ring gear 104, the rotational speed of the ring gear 104 becomes the synchronous rotational speed corresponding to the reduction ratio with respect to the rotational speed of the starter motor 105, or It will be faster than.

  That is, if the ring gear 104 attempts to decrease below the rotational speed of the pinion gear 103, the one-way clutch 107 transmits power, so the rotational speed of the ring gear 104 does not fall below the synchronous rotational speed for the starter motor 105. On the other hand, when the rotational speed of the ring gear is higher than the synchronous rotational speed, the power is not transmitted from the ring gear 104 to the starter motor 105 side because the one-way clutch does not transmit power.

  As shown in FIG. 1, the idle stop system 1 includes an engine whose crankshaft rotates by supplying fuel, a ring gear 104 synchronized with the rotation of the crankshaft, a starter motor 105 that assists engine start, A pinion gear 103 that is engaged with the ring gear 104 and driven to rotate by a starter motor 105 when assisting the start of the engine is provided.

  As shown in FIG. 1, signals from the crank angle sensor 109 (engine speed detector, crank angle detector), signals from the pinion speed sensor 110 (pinion speed detector), the brake switch 111, and the vehicle speed sensor 112 are controlled. Input to the device 108. Since the ring gear 104 and the engine crankshaft are connected, the ring gear rotation speed and the crankshaft rotation speed (engine rotation speed) are synonymous.

  The control device 108 performs normal fuel injection control (control of the fuel injection valve), ignition (control of the spark plug), and air control (control of the electronic control throttle). In addition to this, the control device 108 determines whether the idle stop condition is satisfied from various information (vehicle driving state) such as a brake pedal state based on a signal from the brake switch and a vehicle speed from the vehicle speed sensor 112. Here, when the idle stop condition is satisfied, the engine is allowed to be idle stopped, and the fuel injection valve is controlled to stop the fuel supply to the engine, thereby automatically stopping the engine (the idle stop is performed). ).

  When an engine restart request is generated from the vehicle operating state described above, the control device restarts the fuel supply to the engine by controlling the fuel injection valve, and controls the spark plug to control the ignition timing. To control. In this way, engine restart control is executed.

  The control device 108 outputs a pinion push command signal and a motor rotation command signal independently. As shown in FIG. 1, a magnet switch energizing switch 106a for transmitting a pinion push command signal and a starter motor energizing switch 106b for transmitting a motor rotation command signal control the pushing of the pinion gear 103 and the rotation of the starter motor 105. As the magnet switch energizing switch 106a and the starter motor energizing switch 106b, for example, a relay switch having a mechanical contact, a switch using a semiconductor, or the like can be used.

  In the idle stop system 1 having such a device configuration, the control device 108 performs the following control. FIG. 2 is a control block diagram of a control device that controls the idle stop system according to the first embodiment of the present invention.

  The control device 108 shown in FIG. 1 inputs an output signal of a sensor for detecting the driving state of the vehicle described above via an A / D converter, and based on the input data and data stored in advance in a memory or the like. The idle stop system 1 is controlled by performing the calculation shown in FIG. 4 by the CPU and outputting a control signal via the A / D converter.

  As a software configuration, the control device 108 includes at least control blocks as shown in FIG. Specifically, the idle stop determination unit 201 determines whether or not the vehicle has an idle stop condition based on a vehicle speed signal from a vehicle speed sensor, a brake switch signal, a ring gear rotation speed, and the like. The fuel supply stop unit 202 stops the fuel supply to the engine when the idle stop determination unit 201 satisfies the idle stop condition. Specifically, the fuel supply stop unit 202 controls the fuel injection valve so that fuel is not burned in the engine. At this time, the spark plug may be controlled so as to stop ignition by the spark plug as necessary.

  Here, when the fuel supply to the engine is stopped by the fuel supply stop unit 202, the engine speed decreases. Therefore, inertial rotation determination unit 203 determines whether the engine is inertially rotating when an engine restart request is made. Specifically, the fuel supply stop unit 202 determines whether or not the engine inertia is rotating from when the fuel supply is stopped until the rotation of the crankshaft (engine) is stopped. More specifically, it is determined whether or not the engine inertia is rotating based on the ring gear rotation speed (engine rotation speed) or the amount of change (degree of change in crank angle).

  Here, whether or not an engine restart request has been made is determined by the restart request determination unit 204 based on a brake switch signal or the like. For example, when the brake switch is off, it is determined that an engine restart request has been made. The combustion return unit 205 controls the fuel injection amount, the ignition timing, and the intake air amount to control the fuel injection amount, the fuel ignition plug, and the throttle valve when the above-described combustion return condition is satisfied. Output a control signal. When the inertia rotation determination unit 203 determines that the engine inertia is rotating, the combustion recovery unit 205 supplies fuel to the engine and burns the supplied fuel.

  After the start of fuel supply to the engine by the combustion return unit 205, the restart assist determination unit 207 determines whether or not to assist the restart of the engine by the starter based on the operating state of the engine. Specifically, it is determined from the engine speed (ring gear speed) whether the combustion return start is performed only by the combustion return unit 205 or in addition to this, the starter further assists the engine restart. .

  Further, the restart assist determination unit 207 waits until the cylinder to which fuel is first supplied by the combustion return unit 205 reaches the expansion stroke after fuel supply (specifically, the supplied fuel is ignited) ( Whether the current period is the first period) or after the expansion stroke (second period) is determined. Then, in the first period, the timing for assisting the engine restart by the starter 101 is determined based on the rotational speed difference between the rotational speed of the ring gear and the rotational speed of the pinion gear.

  Here, the rotation speed difference between the rotation speed of the ring gear and the rotation speed of the pinion gear is calculated by a rotation speed difference calculation unit, and when this rotation speed difference becomes a predetermined value or less, the restart assist determination unit 207. Outputs a permission signal for restart assist by the starter 101. On the other hand, in the second period, depending on the state of the engine (engine speed), the combustion recovery start may be performed only by the combustion recovery unit 205. Therefore, when the engine speed is equal to or lower than the predetermined speed, the starter motor assists in restarting the engine.

  The restart assist unit 208 assists restart of the engine by causing the ring gear 104 to be engaged with the pinion gear 103 and driving the starter motor 105 at the timing when the restart assist permission signal is output. Specifically, the restart assist unit 208 outputs a pinion push command signal and a motor rotation command signal, and controls the magnet switch energization switch 106a and the starter motor energization switch 106b. Thereby, an engine restart assist is executed.

  Here, in the present embodiment, the control device 1 further includes an engine speed reduction unit 209. The engine speed reduction unit 209 determines that the restart assist determination unit 207 performs engine restart assist. Then, the restart assist unit 208 reduces the engine speed until the ring gear is engaged with the pinion gear (specifically, until the pinion push command signal is output). In the present embodiment, the engine speed reduction unit decreases the engine speed by prohibiting fuel supply to the combustion return unit.

  When the inertial rotation determination unit 203 determines that the engine inertia is not rotating, when the restart request determination unit 204 satisfies the restart request condition, normal restart assist is performed. At this time, the restart assist determination unit 207 does not determine the restart assist, and the restart assist unit 208 performs the combustion return by the combustion return unit 205 while assisting the engine restart by the starter.

  3 and 4 are flowcharts of the control device shown in FIG. 2, and FIG. 5 is a diagram showing a timing chart of the idle stop system shown in FIG. As shown in FIG. 3, when the idle stop determination unit 201 first determines that the idle stop condition is satisfied in step 301, the process proceeds to step 302. In step 302, the fuel supply stop unit 202 stops the fuel supply in accordance with the establishment of the idle stop condition, and the process proceeds to step 303. At this time, as shown in FIG. 5, at time t1, the fuel supply stop flag changes from Low to High. As a result, the engine rotation starts inertial rotation.

  In step 303, the restart request determination unit 204 determines whether a restart request has occurred. If it is determined in step 303 that a restart request has occurred (time t2 in FIG. 5), the process proceeds to step 304, where inertial rotation determination unit 203 determines whether engine inertial rotation is being performed. Whether or not the engine is in inertial rotation may be determined, for example, from the engine speed or from the degree of change in the crank angle.

  Here, when it is determined that the restart request is determined by the restart request determination unit 204 and the inertia rotation determination unit 203 determines in step 304 that the engine inertia is not rotating, the engine speed and the rotation speed of the pinion gear are Since both are 0 r / min and are synchronized, the routine proceeds to step 321 and normal restart control is performed.

  In normal restart control, as described above, the magnet switch 102 is energized to push out the pinion gear 103 and mesh with the ring gear 104 by the push command signal from the restart assist unit 208. Next, the starter motor 105 is energized by a motor rotation command signal from the restart assist unit 208. As a result, the engine is cranked, fuel supply is restarted (returns to combustion) by the combustion return unit 205, and the engine is restarted.

  On the other hand, if it is determined in step 304 that the engine inertia is rotating, the process proceeds to step 305, the fuel supply is restarted by the combustion return unit 205, and the process proceeds to step 306. In step 306, it is determined whether the read timing of the engine speed Ne1 has been reached.

  Specifically, the reading timing of the engine speed Ne1 is assumed to be the timing after the expansion stroke of the crank angle of the cylinder in which fuel supply is first resumed. That is, even if the fuel supply is resumed in step 305 and restarting by combustion is requested, the engine speed does not increase immediately, but a certain period must be waited. For example, in the case of a PFI engine that injects fuel into an intake port, from the resumption of fuel supply to the expansion stroke in which combustion torque can be obtained from the intake stroke in which fuel is injected in the cylinder in which fuel was initially injected. This is because it takes time.

  Here, in step 306, it is determined whether or not the read timing of the engine speed Ne1 has been reached. If the condition is satisfied (time 3 in FIG. 5), the process proceeds to step 307. That is, when this condition is satisfied, the first cylinder to which fuel has been supplied again is in the state after the expansion stroke. In step 307, the combustion return unit 205 determines whether the engine speed Ne1 exceeds the combustion return determination reference value NeJDG. If this condition is satisfied (Ne1> NeJDG), the process proceeds to step 313 to start combustion return. Determine and restart only by combustion.

  On the other hand, if the engine speed Ne1 is equal to or lower than NeJDG in step 307 (Ne1 ≦ NeJDG), the process proceeds to step 308, and in step 308, the restart assist determination unit 207 determines that the pre-rotation starter assist is started, and then proceeds to step 309 (FIG. 4).

  As shown in FIG. 4, in step 309, the engine speed reduction unit 209 reduces (rotates) the engine speed by prohibiting (stopping) fuel supply from the combustion return unit 205. Next, in step 310, the starter motor 105 is energized to pre-rotate the pinion gear 103. As a result, the pinion gear 103 starts rotating, and the rotational speed of the pinion gear 103 increases. In this specification, the rotation of the starter motor by energization before the ring gear is engaged is referred to as “pre-rotation”.

  Next, at step 311, the restart assist determination unit 207 determines whether or not the difference between the engine speed Ne and the rotation speed Np of the pinion gear 103 is equal to or smaller than the pinion extrusion permission speed difference PIJDG2. When the condition is satisfied ((Ne−Np) ≦ PIJDG2), time t4 in FIG. 5, the process proceeds to step 312 and when the restart assist unit 208 stops energization of the starter motor 105, the pinion gear continues to rotate freely.

  Next, in Step 317, the magnet switch 102 for pushing out the pinion gear 103 is energized. As a result, the pinion gear 103 is pushed out toward the ring gear 104 in a state where the rotational speed difference is small, so that the impact when the pinion gear 103 and the ring gear 104 are engaged is alleviated, and the collision sound and the engagement sound are reduced. In addition, wear of the pinion gear 103 and the ring gear 104 can be reduced.

  Next, at step 318, it is determined whether or not the pinion gear 103 is engaged with the ring gear 104. The biting determination may be determined as biting completion after a predetermined time (period from time t4 to time t5 in FIG. 5) has elapsed since the start of pinion pushing energization in step 317. That is, the period from time t4 to time t5 is the time from the start of pinion push-out energization until the pinion gear 103 moves to reach the ring gear 104 and bite into the ring gear. Alternatively, a sensor that can detect that the pinion gear 103 and the ring gear 104 have been engaged may be provided, and it may be determined that the engagement has been completed based on the output value of the sensor. If the condition is satisfied (time t5 in FIG. 5), the starter motor is energized at step 320, and the engine is cranked and restarted.

  On the other hand, if the condition for the reading timing of the engine speed Ne1 is not satisfied in step 306, that is, the state until the cylinder where the fuel is first supplied by the combustion return unit 205 reaches the expansion stroke after the fuel is supplied. If YES, the routine proceeds to step 314 without waiting for the condition for the reading timing of the engine speed Ne1 to be satisfied. In step 314, the rotation speed difference calculation unit calculates a rotation speed difference (Ne−Np) between the engine rotation speed Ne and the pinion rotation speed Np, and the restart assist determination unit 207 calculates the calculated rotation speed difference (Ne−). It is determined whether or not Np) is equal to or smaller than the pinion extrusion permission rotational speed difference PIJDG1.

  When this condition is satisfied ((Ne−Np) ≦ PIJDG1), the process proceeds to step 315. In step 315, the restart assist determination unit 207 determines starter assist start, and the process proceeds to step 316 (see FIG. 4). In this way, it is possible to determine whether or not the starter assists in restarting the engine until the cylinder to which fuel is first supplied by the combustion return unit 205 reaches the expansion stroke after the fuel is supplied. Therefore, the engine restart assist described later can be performed quickly.

  In step 316, as shown in FIG. 4, the engine speed reduction unit 209 reduces the engine speed by prohibiting (stopping) the fuel supply of the combustion return unit 205, and the process proceeds to step 317. In step 317, the magnet switch 102 for pushing out the pinion gear 103 is energized. In step 318, it is determined whether or not the pinion gear 103 is engaged with the ring gear 104. If the condition is satisfied, the starter motor is energized in step 319 to crank the engine, and then in step 320, the fuel supply is restarted and the engine is restarted.

  Compared to the case where the conventional method continues the fuel supply even if the starter assist start is determined, the method of the present invention stops the fuel supply when the starter assist start is determined at the time t3 in FIG. As a result, the engine speed is not increased due to combustion, the engine speed is quickly decreased, and the time until the pinion and the ring gear are engaged (the period from time t3 to time t5 in FIG. 5) is shortened and restarted. Time is shortened.

[Second Embodiment]
FIG. 6 is a flowchart of the control device of the idle stop system according to the second embodiment. FIG. 7 is a flowchart showing a continuation of the flow shown in FIG. FIG. 8 is a diagram showing a timing chart of the idle stop system according to the second embodiment.

  The control device according to the second embodiment is different from the control device according to the first embodiment in that, as shown in FIG. The pinion gear before being engaged with the ring gear by the starter motor is not pre-rotated until it is pushed out. Of the steps shown in FIGS. 6 and 7, the same steps as the series of steps shown in FIGS. 3 and 4 of the first embodiment are given the same numbers in the last two digits, and detailed descriptions thereof are omitted. To do.

  In the first embodiment, when it is determined that the starter assist start is performed, the starter motor 105 is energized to increase the rotation speed of the pinion gear 103 and then the pinion gear 103 and the ring gear 104 are engaged. In the embodiment, step 310 and step 312 shown in FIG. 4 of the first embodiment are omitted. Therefore, when it is determined that the starter assist start is performed, the engine speed is decreased without increasing the rotation speed of the pinion. After that, the pinion and ring gear are bitten. As a result, the time until the pinion gear engages with the ring gear becomes longer, but the rotation speed difference calculation unit is not required, and it is necessary to independently issue a motor rotation command and a pinion push-out command as in the first embodiment. There is an advantage of being eliminated.

[Third Embodiment]
FIG. 9 is a flowchart of the control device of the idle stop system according to the third embodiment. FIG. 10 is a flowchart showing a continuation of the flow shown in FIG. FIG. 11 is a diagram illustrating a timing chart of the idle stop system according to the third embodiment.

  The control device according to the third embodiment is different from the control device according to the first embodiment in that, in the first embodiment, the engine speed reduction unit prohibits the fuel supply of the combustion return unit, thereby Although the engine speed has been reduced, in the third embodiment, the engine speed reduction unit retards the fuel ignition timing before it is determined to perform the restart assist. Thus, the number of revolutions of the engine is reduced. Specifically, only steps 909 and 916 shown in FIG. 10 are different in a series of control flows.

Therefore, among the steps shown in FIGS. 3 and 4, the same steps as the series of steps shown in FIGS. 3 and 4 of the first embodiment other than steps 309 and 316 attach the same numbers to the lower two digits. (The first digit is changed from 3 to 9), and detailed description thereof is omitted.
Thus, as in the first embodiment, instead of reducing the engine speed by prohibiting the fuel supply of the combustion return part in steps 309 and 316, as in the third embodiment, In step 916, the engine speed is decreased by retarding the fuel ignition timing before the fuel ignition timing before determining that the restart assist is performed.

  Specifically, at least from when it is determined that the restart assist determination unit 207 performs engine restart assist by the starter motor until the restart assist unit 208 causes the ring gear 104 to be engaged with the pinion gear 103. During a part of the period, the engine speed reduction unit 209 determines the fuel ignition timing before the timing at which it is determined to perform the restart assist (or the ignition timing ADV1 before stopping the fuel supply shown in FIG. 11). The engine speed is decreased by retarding the ignition timing of the fuel. In this way, by retarding the fuel ignition timing, the increase in the engine speed due to combustion is reduced, the engine speed is rapidly reduced, and the time until the pinion and the ring gear are engaged (in FIG. 11). (Period from time t3 to time t5) is shortened, and the restart time is shortened.

  In the third embodiment, instead of lowering the engine speed by prohibiting the fuel supply of the combustion return portion in steps 309 and 316 of the first embodiment, restart assistance is performed in steps 909 and 916. The engine speed was decreased by retarding the fuel ignition timing before the fuel ignition timing before the determination.

  In addition to this, as a means for reducing the engine speed, it is possible to reduce the engine speed by making the throttle opening smaller than the throttle opening before determining that the restart assist is performed. Good. That is, by reducing the throttle opening (specifically, by controlling the throttle valve opening in a decreasing direction), the intake negative pressure increases and the pumping loss increases. The rotational speed can be lowered rapidly.

  In addition to this, when the engine has a variable valve mechanism, the engine speed reduction unit retards the intake valve timing before the intake valve timing before determining that the restart assist is performed. Thus, the rotational speed of the engine may be reduced.

  In this way, by controlling the intake air amount or the timing of flowing into the combustion chamber, the engine speed can be reduced. In the first embodiment, prohibition of fuel supply to the combustion return portion, the third embodiment By performing this together with the retarding of the ignition timing in the embodiment, the engine speed can be quickly reduced.

  Furthermore, as another aspect, the engine speed reduction unit may reduce the engine speed by operating a device connected to the crankshaft and applying a load to the engine. Here, equipment connected to the crankshaft, which can be operated to apply a load to the engine, includes an air conditioner compressor, an alternator, and the like. Even in this aspect, by increasing the rotational resistance of the crack shaft, the engine inertia rotation can be quickly lowered, and accordingly, the engine can be restarted quickly.

  The engine to which the present invention is applicable is not limited to an in-cylinder fuel injection type engine, but is an intake port type engine that injects fuel into an intake port, or a dual fuel injection type that uses both an intake port and in-cylinder fuel injection. It can also be applied to other engines. Further, the number of cylinders and the engine type (V type or horizontal opposing type) are not limited and can be applied.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

1: Idle stop system 101: Starter 102: Magnet switch 103: Pinion gear 104: Ring gear 105: Starter motor 106a: Magnet switch energizing switch 106b: Starter motor energizing switch 107: One-way clutch 108: Controller 109: Crank angle Sensor 110: Pinion rotation sensor 111: Brake switch 112: Vehicle speed sensor 201: Idle stop determination unit 202: Fuel supply stop unit 203: Inertia rotation determination unit 204: Restart request determination unit 205: Combustion return unit 207: Restart assist determination Unit 208: restart assist unit 209: engine speed reduction unit t1: fuel supply stop timing t2: restart request generation timing and fuel supply restart timing t3: Ne1 read timing t4: Nion push-out timing t5: Biting completion timing and cranking start timing Ne: Engine rotation speed Np: Pinion rotation speed Ne1: Engine rotation speed PIJDG1 at the timing after the crank angle of the cylinder where fuel supply is first resumed after the expansion stroke : Pinion extrusion permission rotation speed difference PIJDG2: Pinion extrusion permission rotation speed difference NeJDG: Combustion return judgment reference value

Claims (7)

An engine whose crankshaft rotates by supplying fuel;
A ring gear synchronized with the rotation of the crankshaft;
A starter motor that assists in starting the engine;
A pinion gear that engages with the ring gear when assisting the start of the engine and is rotationally driven by the starter motor, and
A control device for an idle stop system that automatically stops the engine by stopping the supply of fuel to the engine when a predetermined idle stop condition is satisfied during engine operation,
The control device includes a fuel supply stop unit that stops supply of fuel to the engine when the predetermined idle stop condition is satisfied during the engine operation,
Inertia for determining whether or not the engine is rotating in an interval from when the fuel supply is stopped by the fuel supply stop unit until the rotation of the crankshaft is stopped when the engine restart request is made. A rotation determination unit;
A combustion return unit for supplying fuel to the engine and burning the supplied fuel when the inertia rotation determination unit determines that the engine inertia is rotating;
A restart assist determination unit that determines whether or not to assist restart of the engine by the starter motor based on an operating state of the engine after the start of fuel supply to the engine by the combustion return unit; ,
When the restart assist determination unit determines to perform the engine restart assist by the starter motor, the ring gear is engaged with the pinion gear, and then the starter motor is driven to drive the engine. A restart assist unit for assisting restart;
After the restart assist determination unit determines that the engine is to be restarted by the starter motor, at least one of the period from when the restart assist unit causes the ring gear to be engaged with the pinion gear. An engine rotation speed reduction unit that reduces the rotation speed of the engine in a period of a part,
The restart assist determination unit includes, as an operating state of the engine, a first period until a cylinder to which fuel is first supplied by the combustion return unit reaches an expansion stroke after fuel supply, and after the expansion stroke. A control apparatus for an idle stop system, characterized in that a second period is determined, and whether or not the restart assist is performed in the determined first period and second period . By stopping the supply of fuel to the engine when a predetermined idle stop condition is satisfied, the engine is automatically stopped,
When assisting the start of the engine with a starter motor, a control device for an idle stop system that rotates by driving a pinion gear into a ring gear of the engine,
The control device includes a combustion return unit that supplies fuel to the engine when the engine is requested to restart during inertial rotation after the predetermined idle stop condition is satisfied, and burns the supplied fuel. ,
A restart assist determination unit that determines whether or not to assist restart of the engine by the starter motor based on an operating state of the engine after the start of fuel supply to the engine by the combustion return unit; ,
Decreasing the engine speed for reducing the engine speed in at least a part of the period from when the restart assist determination unit determines that the assist is performed until the ring gear is engaged with the pinion gear And at least
The restart assist determination unit includes, as an operating state of the engine, a first period until a cylinder to which fuel is first supplied by the combustion return unit reaches an expansion stroke after fuel supply, and after the expansion stroke. A control apparatus for an idle stop system, characterized in that a second period is determined, and whether or not the restart assist is performed in the determined first period and second period .   3. The control device for an idle stop system according to claim 1, wherein the engine speed reduction unit reduces the engine speed by prohibiting fuel supply to the combustion return unit. 4.   The engine speed reduction unit reduces the engine speed by retarding the fuel ignition timing from the fuel ignition timing before determining that the restart assist is performed. Item 3. The control device for the idle stop system according to Item 1 or 2.   The engine speed reduction unit reduces the engine speed by making the throttle opening smaller than the throttle opening before determining that restart assistance is performed. The control apparatus of the idle stop system of 2. The engine has a variable valve mechanism,
The engine speed reduction unit reduces the engine speed by retarding an intake valve timing with respect to an intake valve timing before determining that restart assistance is performed. Or a control device for an idle stop system according to 2. The engine rotational speed reducing unit actuates the device connected to the crank shaft, by applying a load on the engine, according to claim 1 or 2, characterized in that reducing the rotational speed of the engine Control device for idle stop system.

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