JP4862456B2 - Engine starter - Google Patents

Description

  The present invention relates to an engine starter that automatically stops an engine once and automatically starts the stopped engine after an automatic engine stop condition is satisfied.

In recent years, in order to reduce fuel consumption, reduce CO ₂ emissions, etc., the engine is automatically stopped once at idle, and then the engine is automatically restarted when a restart condition such as a start operation is established. Such engine starting devices have been developed.

  This restart of the engine is required to start immediately according to the establishment of the restart condition, so that the engine is started through cranking that drives the engine output shaft by a starter (starting motor), The conventional general starting method which requires a considerable time to complete the starting is not preferable.

  Therefore, fuel is supplied to a cylinder in the expansion stroke of the engine in a stopped state (hereinafter, a cylinder in the expansion stroke when the engine is stopped is referred to as a “expansion stroke in the stop stroke for convenience. The same applies to cylinders in other strokes). Starting methods are being developed that allow combustion to occur and the engine to be started immediately with that energy.

  For example, Patent Document 1 is known as such a technique. Patent Document 1 discloses such a control that the piston position at the time of automatic engine stop is an advantageous position for restarting. According to this method, the piston is stopped at a predetermined proper position by matching the degree of decrease in the engine rotation speed when the engine is automatically stopped with a preset target degree of decrease.

  In Patent Document 1, power generation amount control for increasing or decreasing the power generation amount of the alternator is performed in order to adjust the degree of decrease in engine rotation speed. Since the alternator is driven by the engine, increasing or decreasing the amount of power generation increases or decreases the engine load. The degree of decrease in engine speed is adjusted by increasing or decreasing the engine load.

  In the alternator power generation amount control disclosed in Patent Document 1, the fuel injection is stopped and the target value of the power generation amount is once reduced (for example, 0 A), then increased to a predetermined initial value (for example, 60 A), and then the predetermined control is performed. The power generation amount is adjusted by the width (for example, 0 to 50 A).

By setting the initial value of the power generation amount target value to a high value, the responsiveness of the subsequent power generation amount control is enhanced. Further, by reducing the power generation amount before that, overcharging of the battery is suppressed.
JP 2005-315202 A

  By the way, when the engine is automatically stopped, the degree of decrease in the engine rotation speed after the fuel supply is stopped differs depending on the model and state. For example, when the moment of inertia of the rotating system (so-called inertia) is small, or when the rotational resistance is large (including when the automatic transmission is connected and in a drive state), the rotational speed is relatively rapid. Decreases.

  When the degree of decrease in engine speed is rapid, there is a problem that the battery is temporarily overcharged in the power generation amount control as described below.

  FIG. 5 is an example in which the degree of decrease in the engine rotation speed Ne in the engine automatic stop control is compared. Characteristic 101 is when the automatic transmission connected to the engine is in a drive state (power transmission state), and characteristic 102 is when the automatic transmission is in a neutral state (power transmission is disconnected). In the horizontal axis, t91 indicates the fuel stop time, and t92 indicates the engine complete stop time. From the fuel stop time t91, it can be seen that the degree of decrease in the engine speed Ne is faster in the characteristic 101.

  The engine speed Ne decreases while oscillating in small increments, and the valley of the oscillation is the point at which any cylinder has passed the compression top dead center (TDC). The characteristic 101 has a larger allowance for lowering the engine rotational speed Ne (passage between upper dead points) from the passage of a certain top dead center until the passage of the next top dead center. For example, the top dead center lowering allowances N91 (drive state) and N92 (neutral state) from the third to the second before the engine complete stop are N91> N92 as shown in the figure.

  As described above, when the degree of decrease in the engine rotation speed Ne is rapid, in order to perform effective power generation amount control, a substantial start time of power generation amount control (end time of a period for maintaining the target value of power generation amount at an initial value). ) Needs to be accelerated. Further, when the allowance for lowering the top dead center is increased, the control amount required for the power generation amount control is also increased, so that it is necessary to extend the duration of the initial value. This is because there is a certain amount of delay after the target value is set until the power generation amount actually increases sufficiently.

  For this reason, when the degree of decrease in the engine speed Ne is rapid, the timing for setting the power generation target value to the initial value (large power generation) is set as early as possible, for example, immediately after the fuel stop time t91. Must. If it does so, it will become impossible to provide almost the period which once reduces electric power generation after fuel stop time t91.

  Usually, the battery is controlled so as to always maintain a fully charged state. Therefore, immediately after the fuel stop time t91, if the power generation amount is increased without providing a period for reducing the power generation amount, the battery is temporarily overcharged. This is not desirable because a high voltage is temporarily applied to the electrical component and causes damage such as damage.

  The present invention has been made in view of the above circumstances, and can perform effective power generation amount control while suppressing overcharge of a battery even when the engine rotation speed decreases relatively rapidly. An object of the present invention is to provide an engine starter that can be used.

The invention according to claim 1 for solving the above-mentioned problem is an engine automatic stop control for automatically stopping the engine by stopping the fuel supply for continuing the engine operation when the automatic engine stop condition is satisfied. When the restart condition for the engine in the automatic stop state is satisfied, automatic restart control is performed so that the engine is automatically restarted by performing combustion in the cylinder in the expansion stroke at least when the engine is stopped. Te starting device smell engine with stop and restart control means for performing, an alternator for supplying electric power to an electric generator electric driving part driven by the engine, the power generation amount control for controlling the power generation amount of the alternator And when the power generation amount of the alternator is larger than the power consumption of the electric drive unit, the surplus electricity is charged, and The stop / restart control means has a power generation amount of the alternator that is greater than a power consumption of the electric drive unit at least before the fuel supply stop time. Specific control is started so as to be relatively small, the battery is discharged from the battery to the electric drive unit to reduce the amount of charge of the battery, and then the degree of decrease in the engine rotation speed becomes a predetermined degree of decrease. The power generation amount control for adjusting the power generation amount of the alternator is switched , and the start timing of the specific control is after a predetermined preparation condition that is expected to be established before the automatic stop condition is established, The automatic stop condition is established when a plurality of conditions including that the vehicle speed is equal to or lower than a predetermined vehicle speed and the brake is on, and the preparation condition is as follows: Serial automatic stop condition to, the predetermined vehicle speed, characterized by Rukoto replaced by higher vehicle speed.

According to a second aspect of the invention, the starting apparatus according to claim 1 Symbol placement engine, the stop restart control means includes an engine rotation speed of the fuel supply stop time, and an engine rotational speed of the power generation control start point Further, the present invention is characterized in that it is set to a value higher than the normal idle rotation speed.

According to a third aspect of the present invention, in the engine starting device according to the first or second aspect , the engine has a drive state in which the driving force can be transmitted from the engine side to the driving wheel side, and the driving force. An automatic transmission configured to be able to switch to a neutral state in which transmission is disconnected is connected, and the automatic transmission is maintained in the drive state at least during an engine stop operation period after the fuel supply is stopped. And

A fourth aspect of the present invention is the engine starting device according to any one of the first to third aspects, further comprising battery state detecting means for detecting the state of charge of the battery, wherein the specific control is performed when the battery state of charge is It is characterized in that it is carried out when it is less than a predetermined value than the full charge.

According to a fifth aspect of the present invention, in the engine starting device according to any one of the first to fourth aspects, the specific control includes a control for reducing a power generation amount of the alternator.

According to a sixth aspect of the invention, in the engine starting device according to the fifth aspect of the invention, the reduction in the amount of power generation reduces the target regulated voltage of the alternator by a predetermined value.

According to a seventh aspect of the present invention, in the engine starting device according to any one of the first to sixth aspects, the specific control includes control for increasing power consumption of the electric drive unit.

According to an eighth aspect of the present invention, in the engine starter according to the seventh aspect , the engine temperature detecting means for detecting the temperature of the engine, and an electric fan for cooling the engine, which is a part of the electric drive unit. The control for increasing the power consumption of the electric drive unit includes a control for driving the electric fan when the engine temperature is equal to or higher than a predetermined value and the electric fan is not driven.

  According to the first aspect of the present invention, as described below, even when the engine speed decreases relatively rapidly, effective power generation control can be performed while suppressing overcharge of the battery.

  According to the present invention, the charge state of the battery is less than the fully charged state by the specific control that starts before the fuel supply stop point. Therefore, in the power generation amount control after stopping the fuel supply, even if the power generation amount is increased in the initial stage and surplus electricity is generated with respect to the power consumption of the electric drive unit, the surplus electricity is charged within the range of full charge or less. Can do. That is, overcharge is suppressed. As a result, adverse effects such as unexpected damage to electrical components are suppressed.

  In addition, since the start point of the power generation amount control can be advanced without worrying about overcharging, effective power generation amount control can be performed even when the degree of decrease in the engine rotation speed is rapid.

Furthermore , since the specific control can be started at an early stage before the automatic stop condition is established, a more reliable overcharge prevention effect can be obtained.

Moreover , it can be set as a preliminary condition with a high probability of reaching the automatic stop condition. This is because, after the preliminary condition is satisfied, the automatic stop condition is satisfied only when the vehicle speed is decreased to a predetermined vehicle speed as it is when the brake is turned on.

According to the invention of claim 2 , by increasing the engine rotation speed at the time of stopping the fuel supply, the period until the engine is completely stopped is appropriately extended, and the power generation amount control is facilitated. However, if the rotational speed is too high, the engine rotation noise increases, giving the driver a sense of incongruity, and if connected to an automatic transmission, there is a concern about an increase in creep force, so care must be taken. Although depending on conditions, it is preferable to set the upper limit to about 900 to 1000 rpm.

  Moreover, the start time can be advanced by increasing the engine rotation speed at the start of power generation amount control. That is, since the period during which the power generation amount control is performed can be extended, the degree of decrease in engine rotation speed can be more easily adjusted to the target value.

According to the invention of claim 3 , as described below, an overcharge suppressing effect can be remarkably obtained. If the engine is automatically stopped while the automatic transmission is in the drive state, the engine's rotational resistance (load) increases compared to when the engine is automatically stopped by switching to the neutral state. From the all cylinder fuel supply stop to the engine complete stop The period of is shortened. However, according to the present invention, even in such a case, the power generation amount control can be started early without worrying about overcharging of the battery, and the engine automatic stop control as intended can be performed.

  In addition, since the engine is automatically stopped while the automatic transmission is in the drive state, if there is a request for re-acceleration (accelerator on) during the automatic stop operation period, the vehicle can be smoothly and quickly restored by simply returning the engine combustion. It can be accelerated again.

According to the invention of claim 4 , the control can be simplified as described below. Normally, the battery is controlled to be fully charged at all times, but in some cases it is not. For example, for a device that performs control such that the kinetic energy of the vehicle is converted into electric energy and stored when the vehicle decelerates, a certain amount of charge margin may be secured at all times. In that case, since there is little fear of overcharging by power generation amount control, the specific control can be omitted except when the battery is fully charged. That is, it is possible to suppress redundant control by performing specific control as necessary.

According to the invention of claim 5 , reliable specific control can be performed. The present invention is not intended to exclude increasing the power consumption of the electric drive unit in the specific control, but includes cases where it is used in combination therewith.

According to the invention of claim 6 , the power generation amount of the alternator can be easily reduced.

According to the seventh aspect of the invention, reliable specific control can be performed. The present invention is not intended to exclude reducing the amount of power generated by the alternator in the specific control, but includes cases where it is used in combination therewith.

According to the eighth aspect of the present invention, it is possible to increase the power consumption of the electric drive unit by driving the electric fan reliably and without giving the driver a sense of incongruity. In addition, by cooling a high-temperature engine that is equal to or higher than a predetermined value, it is possible to suppress a warm lock that is a concern during engine restart (a phenomenon in which restart is hindered by self-ignition caused by high-temperature intake air).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic block diagram including an engine starting device according to an embodiment of the present invention. An automatic transmission 50 is connected to the engine body 1. The automatic transmission 50 is a mechanism that automatically converts the engine output into an optimum rotational speed and driving torque and transmits it to the axle according to the traveling state of the vehicle and the operation of the driver. The automatic transmission 50 is configured to be switchable between a neutral state in which transmission of driving force to the wheel side is disconnected and a driving state in which transmission of driving force to the wheel side is possible.

  Further, the engine body 1 is provided with a water temperature sensor 37 as engine temperature detecting means for detecting the temperature of the engine. The water temperature sensor 37 detects the engine temperature based on the temperature of the cooling water circulating inside the engine.

  The engine main body 1 is provided with an alternator 28 (generator) that is driven by the engine. Since the structure of the alternator 28 is well known, it will be described briefly. However, the exciting current of a field coil (not shown) driven by the engine via the belt 27 is controlled by a regulator circuit to adjust the output voltage (regulated voltage) to obtain a predetermined voltage. The power generation amount is obtained. The driving force of the alternator 28 acts as an engine load.

  The electricity generated by the alternator 28 is supplied as a drive source for the electric drive unit 60, and the battery 55 is charged if there is a surplus. The electricity stored in the battery 55 is supplied to the electric drive unit 60 when the amount of power generated by the alternator 28 is insufficient.

  In addition, a battery state detection unit 55 a that detects the charge state of the battery 55 is provided. Specifically, the battery state detection unit 55a includes a current sensor, a voltage sensor, a battery temperature sensor, and the like.

  The electric drive unit 60 is a general term for devices driven by electricity generated by the alternator 28 (including electricity stored in the battery 55), so-called electrical components. The electric drive unit 60 includes, for example, an electric fan 60a for cooling the engine. Although not shown in detail, for example, lights such as headlights, IG (ignition) parts such as spark plugs, audio and navigation systems, blowers (fans for indoor use), additional fans for air conditioners, air conditioners There is a rear defogger (electric heating wire) that removes fogging of the magnetic clutch and rear window glass.

  The engine body 1 is provided with a crank angle sensor 30 (rotational speed detecting means), which detects the rotational speed of a crankshaft (not shown), that is, the engine rotational speed.

  A throttle valve 23 driven by an actuator 24 is disposed in the intake passage 21 of the engine body 1. The throttle valve 23 constitutes an intake air flow rate adjusting means together with a throttle opening degree control unit 2b described later. An air flow sensor 25 that detects the intake air flow rate is provided further upstream of the throttle valve 23.

  In addition, an accelerator opening sensor 34 that detects the depression amount of an accelerator pedal (not shown), a brake switch 35 that detects on / off of a brake, a vehicle speed sensor 36 that detects a vehicle speed, and the like are provided on the vehicle side.

  The ECU 2 is provided as a control unit that controls the combustion of the engine and the operation of the alternator 28 or the electric drive unit 60. The ECU 2 includes a computer having a CPU, a ROM, a RAM, and the like. Specifically, various operations and the like are controlled by executing a program stored in the ROM (or RAM) in advance by the CPU. The ECU 2 is supplied with power from the battery 55 as shown. The ECU 2 receives various signals from the air flow sensor 25, the crank angle sensor 30, the accelerator opening sensor 34, the brake switch 35, the vehicle speed sensor 36, etc., and receives the actuator 24, the electric drive unit 60, an unillustrated ignition plug and fuel. A drive signal is sent to an injection device or the like.

  The ECU 2 performs automatic engine stop control for automatically stopping the engine by stopping the fuel supply for continuing the engine operation when the automatic engine stop condition is satisfied, and for the engine in the automatic stop state. When the restart condition is satisfied, it functions as a stop / restart control means for performing automatic restart control for automatically restarting the engine by causing combustion in at least the cylinder in the expansion stroke when the engine is stopped.

  Further, the ECU 2 starts specific control so that the power generation amount of the alternator 28 becomes relatively smaller than the power consumption of the electric drive unit 60 before the fuel supply stop time, and thereafter, the degree of decrease in the engine rotation speed. Is switched to the power generation amount control that adjusts the power generation amount of the alternator 28 so that a predetermined decrease degree is obtained.

  Hereinafter, in the description of the ECU 2, the parts related to the engine automatic stop control and the specificity control will be mainly described.

  The ECU 2 functionally includes a throttle opening control unit 2b, a fuel supply control unit 2c, an ignition control unit 2d, an alternator power generation amount control unit 2e, and an electric drive unit control unit 2f.

  The throttle opening degree control unit 2b sets an appropriate intake flow rate and outputs an opening degree signal of the throttle valve 23 corresponding to the intake flow rate to the actuator 24. In particular, in the present embodiment, in the automatic engine stop control, the opening degree of the throttle valve 23 is adjusted, and control is performed so that the unillustrated piston stops in an appropriate stop range suitable for restart. The throttle opening degree control unit 2b also adjusts the opening degree of the throttle valve 23 at that time.

  The fuel supply control unit 2c sets the fuel supply (injection) timing and the amount thereof, and outputs the signal to a fuel injection valve (not shown) or the like. In particular, in the engine automatic stop control of this embodiment, as will be described later, when an automatic engine stop condition is satisfied, fuel supply for continuing the engine operation is stopped.

  The ignition control unit 2d sets an appropriate ignition timing for each cylinder, and outputs an ignition signal to an ignition device (not shown).

  The alternator power generation amount control unit 2e sets an appropriate power generation amount of the alternator 28 and outputs the drive signal to the regulator circuit. Normally, a target value (for example, 13 V) of the output voltage (regulated voltage) is set, and the power generation amount is feedback-controlled so that the target value is maintained even if the engine speed or the like fluctuates. Hereinafter, such normal control is also referred to as regulated voltage control.

  In the power generation amount control, the alternator power generation amount control unit 2e performs control such that the engine load is changed by adjusting the power generation amount itself of the alternator 28, and the piston stops in an appropriate range suitable for restart. ing. While the power generation amount control is performed, the output voltage varies according to the power consumption of the electric drive unit 60.

  Further, the alternator power generation amount control unit 2e reduces the power generation amount of the alternator 28 by a predetermined value in the specificity control. The start timing of the specific control is a point in time when a predetermined preparation condition that is expected to be satisfied is satisfied before the automatic engine stop condition is satisfied.

  The electric drive unit control unit 2f controls the electric drive unit 60 including the electric fan 60a. Each electrical component mounted on the engine and the vehicle is appropriately driven automatically according to the state of the engine, the vehicle, etc. or according to the operation of the occupant. In particular, in the present embodiment, in the specific control, the electric fan 60a is forcibly driven on the condition that the engine temperature is a predetermined high temperature (for example, cooling water temperature ≧ 80 ° C.).

  FIG. 2 is a time chart when the engine is automatically stopped by the engine automatic stop control. The upper part shows the engine rotational speed Ne (rpm), and the lower part shows the target power generation amount Alt of the alternator 28. The target power generation amount Alt is shown with the maximum power generation time as 100%.

  This time chart shows a case where an automatic engine stop condition (hereinafter also referred to as an idle stop condition) is satisfied when the automatic transmission 50 is in a drive state. At this time, in the present embodiment, the engine is automatically stopped while the automatic transmission 50 is in the drive state. By doing so, when there is a reacceleration request (accelerator on) during the automatic stop operation period, there is an advantage that the vehicle can be reaccelerated smoothly and quickly only by returning the combustion of the engine.

  The outline of this time chart is as follows. First, the idle stop condition is satisfied at time t2, and the fuel supply is stopped at time t4. Thereafter, the engine speed Ne decreases and the engine is completely stopped at time t7. The idle stop condition that is satisfied at time t2 is, for example, a vehicle speed of 0 km / h (stopped state), accelerator off, brake on, air conditioner off, automatic transmission 50 lockup off, steering steering angle below a predetermined value, turn signal off, The battery voltage is equal to or higher than a predetermined value.

  Next, this time chart will be described in detail in chronological order. Normal engine control is performed at the start of this time chart. Therefore, the alternator power generation amount control unit 2e performs the regulated voltage control TA. The target regulated voltage is set to a normal value (for example, 13V). The regulator circuit of the alternator 28 performs feedback control of the target power generation amount Alt so that the output voltage of the alternator 28 becomes the target regulated voltage. At this time, the charged amount of the battery 55 is maintained in a fully charged state.

  Time t1 is the time when the idle stop preparation condition is satisfied. The idle stop preparation condition is substantially the same as the idle stop condition, but only the vehicle speed condition is different. That is, the idle stop preparation condition is satisfied when an idle stop condition other than the vehicle speed is satisfied and the vehicle speed is equal to or lower than a predetermined low vehicle speed (about 10 to 15 km / h). Since the brake is on when the idle stop preparation condition is satisfied, it is highly likely that the vehicle will stop soon after time t1 and the idle stop condition is also satisfied. That is, the idle stop condition is expected to be satisfied.

  When the idle stop preparation condition is satisfied at time t1, the ECU 2 executes the specific control TB. That is, the alternator power generation amount control unit 2e reduces the target regulated voltage (for example, 13V → 12V). As a result, the target power generation amount Alt is reduced. Accordingly, the actual power generation amount is also reduced, so that electric power is supplied from the battery 55 to the electric drive unit 60 in order to compensate for the decrease in the power generation amount. As a result, the amount of charge of the battery 55 is less than the fully charged state.

  In this specific control TB, when the engine coolant temperature is equal to or higher than a predetermined temperature (for example, 80 ° C.), the electric drive control unit 2f drives the electric fan 60a. When the electric fan 60a is changed from the non-driven state to the driven state, the power consumption of the electric drive unit 60 is increased correspondingly, so that the discharge of the battery 55 is further promoted.

  When the idle stop condition is satisfied at time t2, the ECU 2 executes automatic engine stop control. First, the engine target rotational speed is set to a target rotational speed higher than the normal idle rotational speed (the engine rotational speed Ne has increased since time t2). By doing so, the period from the fuel supply stop (t4) to the engine complete stop (t7) is appropriately extended, and control for stopping the piston at the target position is facilitated. In the present embodiment, the normal idle rotation speed when the automatic transmission 50 is in the drive state is set to 650 rpm, and the target rotation speed is set to about 850 to 900 rpm.

  Further, at time t2, the throttle opening degree control unit 2b adjusts the throttle valve 23 so that the intake pressure becomes about −400 mHg. This is part of the control for stopping the piston at a position advantageous for restart when the engine is completely stopped at time 7.

After time t2, at time t3 a predetermined time _{T 23} (for example, about 200 ms) has elapsed, ECU 2 is (also end at the same time regulated voltage control _{T A)} switches the specificity control _{T B} to the power generation amount control _{T C.} The power generation control _{T C,} first of predetermined time _{T 34} (for example, about 200 ms), the target power generation amount Alt is held at a constant value (e.g., 30%). By doing so, the variation in the actual power generation amount increase characteristic when the target power generation amount Alt is increased at a later time t4 is reduced.

  At the time point t4 when the predetermined time T34 has elapsed, it is confirmed that the engine speed is stable at the target speed, and the fuel supply is stopped.

  After time t4, the target power generation amount Alt is temporarily set to a relatively large initial value (for example, 100%). By increasing the power generation amount in this way, the responsiveness of the subsequent control can be improved. Further, even when the power generation amount exceeds the power consumption of the electric drive unit 60 due to the increase in the power generation amount, the charge margin of the battery 55 is secured by the specific control TB, so that proper charging is performed. That is, overcharge is suppressed and an excessive voltage is applied to the electric drive unit 60 to prevent damage.

  The alternator power generation amount control unit 2e when the engine rotation speed Ne decreases to a predetermined value N1 (which is preferably set to a relatively high value, for example, a value higher than the normal idle rotation speed of 650 rpm) as the fuel supply is stopped. Adjusts the target power generation amount Alt with a predetermined control width A1. That is, when the degree of decrease in the engine rotation speed Ne is more rapid than the preset target value, the target power generation amount Alt is reduced to reduce the engine load, and conversely from the preset target value. If it is moderate, the target power generation amount Alt is increased to increase the engine load. By doing so, the engine rotational speed Ne decreases along the preset target value, and as a result, the probability that the piston stops at the appropriate position can be increased.

  On the other hand, after time t4, the throttle opening control unit 2b closes the throttle valve 23 at a predetermined engine rotational speed Ne and performs control so that an appropriate intake amount is distributed to each cylinder when the engine is stopped.

  The target power generation amount Alt is set to 0% at the time point t6 when the engine rotation speed Ne decreases to a predetermined value. As a result, the behavior of the piston immediately before the engine stops can be stabilized. By setting the engine speed N1 to a relatively high value, the period from time t5 to time t6 can be made relatively long. Therefore, it becomes easy to adjust the degree of decrease in the engine rotational speed Ne by increasing or decreasing the target power generation amount Alt.

  In this way, the engine rotation speed Ne decreases along the target decrease degree. Therefore, when the engine is completely stopped at the time point t7, the piston is stopped in an appropriate range with a high probability.

  3 to 4 are schematic flowcharts at the time of automatic engine stop including the specific control TB. When this flowchart is started and the idle stop preparation condition is satisfied (YES in step S1), the specific control TB is started. In the specific control TB, first, the battery state is detected by the battery state detection unit 55a (step S3). When the battery charge amount is equal to or greater than a predetermined value (value close to full charge) (YES in step S5), the target regulated pressure is reduced (13V → 12V). If it is determined NO in step S5 for some reason, step S7 is omitted.

  Next, it is confirmed whether or not the engine coolant temperature is 80 ° C. or higher (step S9). If YES, the electric fan 60a is forcibly driven (step S11). It is maintained (step S13). Then, it is determined whether or not the idle stop condition is satisfied (step S15), and the routine of steps S3 to S15 is repeated until it is determined YES.

  If the idle stop condition is satisfied (YES in step S15), the engine rotational speed Ne and the intake pressure are set to predetermined target values (step S17). Then, the fuel stop (F / C) counter CT is reset (step S19), and when the predetermined waiting time T23 (200 ms) has elapsed (steps S21 to S23), the alternator 28 is regulated voltage control TA (specificity). The control TB is switched to the power generation amount control TC, and the target power generation amount Alt is held at a constant value (for example, 30%) (step S25).

  This state is further maintained for a period of time T34 (200 ms) (steps S27 to 29), and when the F / C start counter CT> T23 + T34 is satisfied (YES in step S27), the fuel supply is stopped and the engine automatic stop control is performed. Is continued (step S31), and the process returns.

  When the restart condition is satisfied after the engine is completely stopped, the ECU 2 executes automatic restart control for automatically restarting the engine by causing combustion at least in the cylinder in the expansion stroke when the engine is stopped. At that time, combustion in the expansion stroke cylinder may be performed from the beginning (forward rotation start method), or combustion is performed in the compression stroke cylinder before that, and the engine is reversed once to increase the in-cylinder pressure of the expansion stroke cylinder. Combustion in the expansion stroke cylinder may be performed after increasing (reverse starting method). In any case, the cylinder that is in the intake stroke at the time of stoppage is inhaled by high-temperature air that has accumulated in the surge tank, and may self-ignite (warm lock) during the first compression stroke of the cylinder. Consideration is necessary. This is because warm restart will hinder smooth restart.

  In this respect, in the present embodiment, since the electric fan 60a is driven to cool the engine when the engine temperature is high (water temperature ≧ 80 ° C.), warm lock is suppressed. In other words, the electric fan 60a is driven to forcibly consume the electric power to suppress overcharge of the battery 55, and the electric power can be effectively used for preventing the warm lock.

  As mentioned above, although embodiment of this invention was described, this embodiment can be suitably changed in the range which does not deviate from the summary of this invention. The modification will be described below.

  (1) In the above embodiment, the start timing t1 of the specific control TB is set to the idle stop preparation condition time point before the idle stop condition is satisfied, but it is not always necessary to do so, and may be before the fuel supply stop time point t4. It ’s fine. However, according to the above-described embodiment, it is possible to sufficiently secure the execution time of the specific control TB and increase the charge margin of the battery 55. It is also advantageous in that the time (T23 + T34) from the time t2 when the idle stop condition is satisfied to the time t4 when the fuel supply is stopped can be shortened as much as possible.

  (2) Although the vehicle speed condition of the idle stop condition of the above embodiment is the vehicle speed V = 0 km / h, it may be higher than this, for example, about 10 to 20 km / h. In that case, the vehicle speed condition of the idle stop preparation condition may be set to a slightly higher vehicle speed than the vehicle speed. Further, the difference between the idle stop condition and the idle stop preparation condition is not limited to that of the above embodiment, and if the idle stop preparation condition is satisfied, it is considered that the idle stop condition will be satisfied soon with a relatively high probability. If it is good.

  (3) In the above embodiment, the battery 55 is controlled to be fully charged at all times. For example, it may be applied to a control that converts the kinetic energy of the vehicle into electric energy and stores the electric power when the vehicle decelerates, and always secures a certain amount of charge allowance. However, the effect of the present invention can be remarkably enjoyed when applied to a device that is controlled so as to be always fully charged.

  (4) The electric drive unit 60 driven in the specific control TB is not limited to the electric fan 60a. Other than the electric fan 60a, a fan that consumes a relatively large amount of power and does not give the passenger a sense of incongruity even when it suddenly operates automatically (for example, a rear defogger) is preferable. Further, an electric fan 60a may be used instead of the electric fan 60a when the engine temperature is low even if the engine temperature is low.

  (5) In the above embodiment, the automatic transmission 50 automatically stops the engine while in the drive state. However, the present invention is not necessarily limited to this, and the automatic transmission 50 is in the neutral state and the engine is automatically stopped. You may apply to. Note that the drive state or neutral state of the automatic transmission 50 refers to the power transmission mode and does not necessarily coincide with the position of the shift lever or the like operated by the driver. For example, even if the position of the shift lever is in the “D” range, the automatic transmission 50 can be set to the neutral state by releasing the power transmission system (such as a hydraulic clutch) inside the automatic transmission 50.

1 is a schematic block diagram including an engine starter according to an embodiment of the present invention. It is a time chart at the time of engine automatic stop by engine automatic stop control including specific control. It is the first half of the general | schematic flowchart at the time of the engine automatic stop including specific control. It is the latter half of the flowchart of FIG. It is a figure which shows the comparison of the fall degree of the engine speed in engine automatic stop control.

1 Engine body 2 ECU (stop / restart control means)
2e Alternator power generation amount control unit (power generation amount control means)
28 Alternator 37 Water temperature sensor (Engine temperature detection means)
50 automatic transmission 55a battery state detection unit (battery state detection means)
55 Battery 60 Electric drive unit 60a Electric fan TB Specific control TC Power generation amount control

Claims (8)

When the engine automatic stop condition is satisfied, the engine automatic stop control for automatically stopping the engine by stopping the fuel supply for continuing the engine operation and the restart condition of the engine in the automatic stop state are performed. Te but when satisfied, to perform combustion at cylinder in the expansion stroke at least the engine stopped starting device smell engine with stop and restart control means for performing automatic restart control for automatically restarting the engine ,
An alternator for supplying electric power to an electric generator electric driving part driven by the engine,
Power generation amount control means for controlling the power generation amount of the alternator;
A battery that charges the surplus electricity when the power generation amount of the alternator is larger than the power consumption of the electric drive unit, and supplies the electric drive unit with the shortage when the generated amount is small;
The stop / restart control means starts specific control so that the power generation amount of the alternator becomes relatively smaller than the power consumption of the electric drive unit at least before the fuel supply stop time, and from the battery To reduce the amount of charge of the battery by discharging to the electric drive unit, and then switching to the power generation amount control that adjusts the power generation amount of the alternator so that the reduction degree of the engine rotation speed becomes a predetermined reduction degree ,
The start time of the specific control is after the time when a predetermined preparation condition that is expected to be satisfied is satisfied before the automatic stop condition is satisfied,
The automatic stop condition is established when a plurality of conditions including that the vehicle speed is equal to or lower than a predetermined vehicle speed and the brake is on are satisfied,
The engine starter characterized in that the preparation condition is obtained by replacing the predetermined vehicle speed with a higher vehicle speed than the automatic stop condition . The stop / restart control means sets the engine rotation speed when the fuel supply is stopped and the engine rotation speed when the power generation amount control is started to a value higher than a normal idle rotation speed. Item 4. The engine starting device according to Item 1. The engine is connected to an automatic transmission configured to be able to switch between a driving state in which driving force can be transmitted from the engine side to the driving wheel side and a neutral state in which transmission of the driving force is disconnected. ,
3. The engine starter according to claim 1 , wherein the automatic transmission is maintained in the drive state at least during an engine stop operation period after the fuel supply is stopped . Battery state detection means for detecting the state of charge of the battery,
The engine starting device according to any one of claims 1 to 3, wherein the specific control is omitted when the battery charge state is other than full charge . 5. The engine starter according to claim 1 , wherein the specific control includes control for reducing an amount of power generated by the alternator . 6. 6. The engine starting device according to claim 5, wherein the reduction of the power generation amount is a reduction of a target regulated voltage of the alternator by a predetermined value . The engine start device according to any one of claims 1 to 6, wherein the specific control includes control for increasing power consumption of the electric drive unit . Engine temperature detecting means for detecting the temperature of the engine;
A part of the electric drive unit, comprising an electric fan for cooling the engine;
The control for increasing the power consumption of the electric drive unit includes a control for driving the electric fan when the engine temperature is equal to or higher than a predetermined value and the electric fan is in a non-driven state. The engine starting device as described.

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