JP2018105249A - Restart control device - Google Patents

Abstract

There is provided a restart control device capable of increasing the rotational speed of a crankshaft so as to pass through a resonance region quickly without depending on the rotational angle position of the crankshaft when the engine is stopped. A restart system comprising an engine (10), a rotating electrical machine (12), and a crank angle sensor (33), wherein the engine is automatically stopped while the engine is automatically restarted. A control device (30), a stop crank angle acquisition unit that acquires a stop crank angle, which is a crank angle in a state where the engine is automatically stopped, from a crank angle sensor, and a plurality of units after a predetermined restart condition is satisfied During the period up to the second compression top dead center of the cylinder, power running control, negative torque application control, power running control and negative torque application control are waited based on the stop crank angle acquired by the stop crank angle acquisition unit. A restart control device comprising: standby control; and a rotating electrical machine control unit that selects and implements one of at least two controls. [Selection] Figure 1

Description

  The present invention relates to a control device that controls restart of an engine.

  In recent years, for example, a vehicle having an idling stop function (hereinafter referred to as an idling stop vehicle) has been put into practical use for the purpose of improving fuel efficiency and the like, and an engine must be started as soon as possible after restarting after idling stop. . For this reason, in order to improve the responsiveness of engine restart, for example, a technique disclosed in Patent Document 1 has been studied.

  In Patent Document 1, when a predetermined automatic stop condition is satisfied, the intake throttle valve is driven in the closing direction, and is controlled to be smaller than the opening before the automatic stop condition is satisfied. Then, during the intake stroke of the cylinder that becomes the compression stroke when the engine is stopped after the fuel injection by the fuel injection valve is stopped (hereinafter referred to as the compression stroke cylinder at the time of stop), the last top dead center (hereinafter, The intake throttle valve is driven in the opening direction when passing the top dead center immediately before the final TDC). As a result, even if the piston swings back and the engine temporarily rotates in the reverse direction, the piston of the compression stroke cylinder at the time of stop stops in the compression stroke without exceeding the top dead center. Here, if the stop position of the piston falls within a specific range set between the top dead center and the bottom dead center, the first combustion of the fuel can be started in the stop compression stroke cylinder as a whole, and the engine It can be restarted quickly.

JP 2013-113161 A

  However, by performing the piston stop position control described in Patent Document 1, if the intake throttle valve is opened and air is introduced before the engine stops, the compression reaction force in the cylinder increases, and as a result, the engine stops. There is a concern that the vibration of the engine, which sometimes occurs, becomes large. For this reason, when the automatic stop control described in Patent Document 1 is performed, it is considered that there is a limit on the amount of opening that drives the intake throttle valve in the opening direction, and depending on the size of the limit, the compression stroke at the time of stop There is a possibility that the controllability of the piston stop position of the cylinder may be lowered.

  By the way, the engine has a resonance region of rotational vibration, and it is desirable that the rotational speed of the engine quickly passes through the resonance region when the engine is restarted in order to suppress engine vibration. However, when the automatic stop control described in Patent Document 1 is performed, the above-described concern arises, and when the piston stop position of the stop-time compression stroke cylinder when the engine is automatically stopped is out of a specific range, the engine Compared with the case where the piston stop position of the compression stroke cylinder during stop when it is automatically stopped falls within a specific range, the period during which the engine speed when the engine is restarted is within the resonance range is longer there is a possibility. In this case, the vibration of the engine at the time of engine restart increases.

  The present invention has been made to solve the above-mentioned problems, and its main purpose is not to depend on the rotational angle position of the crankshaft when the engine is stopped, and the rotational speed of the crankshaft so as to pass through the resonance region quickly. An object of the present invention is to provide a restart control device that can raise the engine.

  The present invention includes an engine having a plurality of cylinders, a rotating electrical machine provided so that torque can be transmitted to the crankshaft of the engine, and a crank angle sensor that detects a crank angle of the crankshaft. A restart control device that is applied to a vehicle that performs automatic restart of the engine on condition that a predetermined restart condition is satisfied, while the engine is automatically stopped. A stop crank angle acquisition unit that acquires a stop crank angle that is the crank angle from the crank angle sensor, and a second compression top dead of the plurality of cylinders after the predetermined restart condition is satisfied in the automatic restart Based on the stop crank angle acquired by the stop crank angle acquisition unit during a period up to a point, the crankshaft At least two controls: a power running control that applies a positive torque, a negative torque application control that applies a negative torque to the crankshaft by the rotating electrical machine, and a standby control that waits for the power running control and the negative torque application control And a rotating electrical machine control unit that selects and implements one control.

  Controlling the intake throttle valve in the opening direction when the engine is stopped increases the vibration of the engine that occurs when the engine is stopped.When performing piston stop position control, the amount of opening that drives the intake throttle valve in the opening direction is limited. Is considered to be provided. At this time, depending on the size of the restriction, the controllability of the piston stop position of the cylinder (hereinafter referred to as the first cylinder) that becomes the compression stroke when the engine is stopped among the plurality of cylinders may be lowered. If the above-mentioned concern arises when the piston stop position control is performed, the time during which the rotation speed of the crankshaft is within the resonance range is increased, and the engine vibration may be increased when the engine is restarted.

  As a countermeasure, the stop crank angle is acquired from the crank angle sensor. In the automatic restart, the power running control and the power running control are performed based on the stop crank angle acquired by the stop crank angle acquisition unit during a period from when a predetermined restart condition is satisfied to the second compression top dead center of the plurality of cylinders. One control is selected from at least two of the negative torque application control and the standby control, and is executed. That is, even if the piston stop position of the first cylinder deviates from the specific range to the top dead center side or the bottom dead center side, the predetermined restart condition is satisfied until the second compression top dead center of the plurality of cylinders. By appropriately adjusting the rotational speed of the crankshaft by the rotating electrical machine during the period, it is possible to increase the rotational speed of the crankshaft so as to pass through the resonance region quickly.

  In a second aspect based on the first aspect, the rotating electrical machine is capable of applying a negative torque to the crankshaft, and the rotating electrical machine control unit acquires the stop crank angle acquired by the stop crank angle acquisition unit. Is selected and executed on the condition that is smaller than a first threshold value in the positive rotation direction of the crankshaft.

  The situation where the crankshaft stop crank angle acquired by the stop crank angle acquisition unit is smaller than the first threshold is when the crankshaft stop crank angle acquired by the stop crank angle acquisition unit is larger than the first threshold. In comparison, the piston stop position of the first cylinder is on the bottom dead center side, indicating a situation in which the time until the first cylinder reaches the compression top dead center after a predetermined restart condition is satisfied is indicated. . Therefore, the rotation speed of the crankshaft when the first cylinder reaches the compression top dead center is higher than when the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is larger than the first threshold. It is assumed that At this time, if the engine (first cylinder) burns fuel, the rotational speed of the crankshaft may enter the resonance region due to the rotational torque generated at that time. As a countermeasure against this, the second compression top dead of a plurality of cylinders after a predetermined restart condition is satisfied on condition that the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is smaller than the first threshold value. During the period up to the point, negative torque application control is selected and executed. Thereby, the rotational speed of the crankshaft when the first cylinder reaches the compression top dead center can be kept low, and the rotational speed of the crankshaft when the engine (first cylinder) performs fuel combustion. Can be kept low in the resonance region.

  According to a third invention, in the first or second invention, the rotating electrical machine can wait for the application of the negative torque to the crankshaft and the application of the positive torque to the crankshaft, The rotating electrical machine control unit is configured such that the stop crank angle acquired by the stop crank angle acquisition unit is larger than a first threshold value and smaller than a second threshold value set larger than the first threshold value. The standby control is selected and executed.

  When the stop crank angle acquired by the stop crank angle acquisition unit is larger than the first threshold and smaller than the second threshold set larger than the first threshold, the piston stop position of the first cylinder is It is considered that the engine is stopped within a range (specific range) in which the engine can be restarted suitably. Therefore, when a predetermined restart condition is established in the above situation, the resonance of the rotating electric machine with normal engine restart is performed without applying negative torque or positive torque to the crankshaft. It is possible to increase the rotational speed of the crankshaft so as to pass through the region as soon as possible.

  In a fourth aspect based on the second or third aspect, the rotating electrical machine can apply the positive torque to the crankshaft, and the rotating electrical machine control unit is acquired by the stop crank angle acquiring unit. When the stop crank angle is larger than a second threshold set larger than the first threshold, the power running control is selected and executed.

  The situation where the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is larger than the second threshold is when the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is smaller than the second threshold. In comparison, the piston stop position of the first cylinder is on the top dead center side, and the time from when a predetermined restart condition is satisfied until the first cylinder reaches the compression top dead center is short. When engine restart control is performed in this situation, the rotational speed of the crankshaft is increased to a rotational speed at which the engine can be started by fuel combustion before the first cylinder reaches compression top dead center. May not be possible. In such a case, the first fuel combustion cannot be performed in the first cylinder after the predetermined restart condition is satisfied, so that the cylinder that reaches the compression top dead center (hereinafter referred to as the second cylinder). The fuel is burned in a cylinder). At this time, the combustion of the fuel by the second cylinder is performed in a situation where the rotation speed of the crankshaft is lower than in the case of burning the fuel in the second cylinder after burning the fuel in the first cylinder. Become. Therefore, in the fuel combustion of the second cylinder in the above situation, the rotation speed of the crankshaft cannot be prevented from passing back through the resonance region, and the rotation speed of the crankshaft enters the resonance region a plurality of times. There is a risk that the vibration of the engine will increase during the period.

  As a countermeasure, when the stop crank angle acquired by the stop crank angle acquisition unit is larger than the second threshold, the period from when a predetermined restart condition is satisfied to the second compression top dead center of the plurality of cylinders The power running control is selected and executed. As a result, the rotation speed of the crankshaft can be sufficiently increased by the time when the fuel is burned in the second cylinder so that the fuel passes through the resonance region as soon as the fuel is burned by the second cylinder.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the rotating electrical machine control unit is configured to be monotonous until the rotational speed of the crankshaft reaches the resonance range of the engine and then comes out of the resonance range. The selected control is performed so as not to rise and return to the resonance region.

  By performing the above control, the rotation speed of the crankshaft does not stagnate in the resonance region, and can pass through the resonance region quickly.

  According to a sixth aspect, in the fourth aspect, the rotational speed calculation unit that calculates the rotational speed of the crankshaft is calculated based on the crank angle detected by the crank angle sensor, and the rotational speed calculation unit. A rotation angle estimator that estimates a rotation angle of the rotating electrical machine when the rotation speed of the crankshaft is higher than an estimated threshold, and does not estimate a rotation angle of the rotating electrical machine in a state lower than the estimated threshold; The rotating electrical machine control unit performs the power running control during a period from the first compression top dead center of the plurality of cylinders to the second compression top dead center of the plurality of cylinders.

  In order to apply a positive torque to the crankshaft by the rotating electrical machine, it is necessary to correctly recognize the rotation angle of the rotating electrical machine. In this regard, when the rotation angle sensor for detecting the rotation angle of the rotating electrical machine is not provided, it is necessary to estimate the rotation angle of the rotating electrical machine. However, it is often difficult to estimate the rotation angle of the rotating electrical machine when the rotation speed of the crankshaft is lower than the estimated threshold value. Therefore, there is a possibility that the rotation speed of the crankshaft is lower as it falls below the estimated threshold during the period from when the predetermined restart condition is satisfied until the first compression top dead center of the plurality of cylinders. It is considered difficult to carry out normally. Therefore, during the period from the first compression top dead center of the plurality of cylinders to the second compression top dead center of the plurality of cylinders, the power running control is performed by the rotating electrical machine control unit. As a result, power running control can be performed under circumstances where the engine speed is unlikely to fall below the estimated threshold.

  In a seventh aspect based on any one of the first to sixth aspects, the rotating electrical machine control unit has reached the second compression top dead center of the plurality of cylinders after the predetermined restart condition is satisfied. The power running control is performed.

  The scene where the rotational speed of the crankshaft passes through the resonance region is often the time when the rotational speed increases due to the combustion of fuel in the second cylinder. Therefore, the power running control is performed after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached. As a result, not only the rotational torque generated by the combustion of fuel in the second cylinder but also positive torque is applied to the crankshaft by the rotating electrical machine, so the degree of increase in the rotational speed of the crankshaft increases and the rotational speed of the crankshaft resonates. The possibility of being able to pass without stagnating in the area can be increased.

  According to an eighth invention, in any one of the first to seventh inventions, the vehicle includes a starter for starting the engine, and the crankshaft is rotated by the starter when the predetermined restart condition is satisfied. And a restart unit that restarts the engine.

  In a ninth aspect based on the eighth aspect, the rotating electrical machine control unit performs the power running control after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached. The restarting unit stops driving of the starter when the power running control is performed after reaching the second compression top dead center of the plurality of cylinders by the rotating electrical machine control unit.

  When a predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached, when a positive torque is applied to the crankshaft by the rotating electrical machine, the drive of the starter is stopped. Thereby, compared with the case where starter drive is continued until the engine reaches the complete explosion, noise and vibration due to the starter can be suppressed.

  In a tenth aspect based on the eighth aspect, the restart unit continues driving the starter until the engine reaches a complete explosion.

  By continuing the starter drive until the engine reaches a complete explosion, the engine can be reliably started.

It is a schematic block diagram of the control system which concerns on this embodiment. It is a figure which shows the mode of the pulsation of the rotational speed of a crankshaft which arises by implementing control which opens an intake throttle valve when stopping an engine, and the vibration of an engine. It is a time chart which shows the aspect of the restart control which concerns on this embodiment. It is a time chart which shows the aspect of the restart control which concerns on this embodiment, and the aspect when this restart control is not implemented. It is a time chart which shows the aspect of the restart control which concerns on this embodiment, and the aspect when this restart control is not implemented. It is a control flowchart which ECU which concerns on this embodiment implements. It is a subroutine process of step S150 described in FIG. It is another example of the subroutine processing described in FIG.

  Hereinafter, the present embodiment will be described with reference to the drawings.

  FIG. 1 shows an example of a control system 100 connected to an internal combustion engine (hereinafter referred to as an engine) 10 having a plurality of cylinders.

  The engine 10 is provided with a starter motor 16. The pinion gear attached to the starter motor 16 is mechanically engaged with the ring gear 15 of the engine 10 when the engine 10 is started according to the start command, and positive torque is applied to the crankshaft 11 from the outside to Start.

  A crankshaft 11 of the engine 10 is connected to a rotating electrical machine 12. In this embodiment, the rotating electrical machine 12 is assumed to be a belt-driven alternator connected to the crankshaft 11 via a belt. This alternator includes a multiphase winding and a field winding, and rectifies an AC output current output from the multiphase winding by a plurality of MOSFETs, and is also referred to as a MOS-Alt. By controlling this MOSFET, the rotating electrical machine 12 as the MOS-Alt can have a power running function in addition to a negative torque applying function for applying a negative torque to the crankshaft 11. The power running function applies a positive torque from the outside to the crankshaft 11 at the time of start-up after warm-up such as idling stop restart (restart from automatic engine stop) until the engine 10 reaches a complete explosion. It is a function. Moreover, the rotary electric machine 12 has a standby function for waiting for the execution of the negative torque applying function and the power running function. The rotating electrical machine 12 is connected to the ECU 30 via a communication network such as LIN.

  The engine 10 includes a crank angle sensor 33 and transmits a rectangular crank angle signal to the ECU 30 for each predetermined crank angle of the engine 10 (for example, at a cycle of 30 ° CA).

  The control system 100 includes an electric load 13 and a lead storage battery 14 in addition to the rotating electrical machine 12, the starter motor 16, and the ECU 30.

  The lead storage battery 14 is a known general-purpose storage battery. Specifically, the positive electrode active material is lead dioxide (PbO2), the negative electrode active material is lead (Pb), and the electrolytic solution is sulfuric acid (H2SO4). And the some battery cell comprised from these electrodes is connected in series, and is comprised. The lead storage battery 14 is electrically connected in parallel by a starter motor 16 and a feeder line 15 as a connection line via a relay 20.

  The relay 20 is connected by a drive signal from the ECU 30. When the engine 10 is started in accordance with the start command, a drive signal is transmitted to the relay 20 by the ECU 30, and when the relay 20 is connected, the starter motor 16 is rotated by the electric power supplied from the lead storage battery 14. Thereby, the engine 10 is started by applying a positive torque to the crankshaft 11 from the outside. The same control is performed even when restarting from a state where the engine 10 is automatically stopped. On the other hand, when the relay 20 is in the cut-off state, the supply of electric power from the lead storage battery 14 is stopped, and the starter motor 16 is not driven.

  The electric load 13 is a general electric load. Specific examples thereof include a headlight, a wiper such as a front windshield, a blower fan for an air conditioner, and a defroster heater for a rear windshield. The electrical load 13 is electrically connected in parallel with each of the rotating electrical machine 12 and the lead storage battery 14 by the power supply line 15, and thereby, power is supplied from the rotating electrical machine 12 and the lead storage battery 14 to the electrical load 13. .

  The control system 100 includes an ECU 30 as a main control device that controls the entire system. The ECU 30 is a known electronic control device including a microcomputer and the like.

  The ECU 30 causes the engine 10 to be automatically stopped when a predetermined automatic stop condition is satisfied while the vehicle is traveling. The engine 10 is automatically restarted when the automatic stop of the engine 10 is performed and a predetermined restart condition is satisfied. As the automatic stop condition, for example, the vehicle speed is equal to or lower than a predetermined value, the accelerator operation amount detected by an accelerator sensor (not shown) is zero (or a brake detected by a brake sensor (not shown)). The operation amount is larger than the first predetermined amount). Further, the predetermined restart condition includes, for example, that the accelerator operation amount detected by the accelerator sensor is larger than the second predetermined amount, the brake operation amount detected by the brake sensor is zero, and the like.

  On the other hand, the ECU 30 controls the operation of each part including the starter motor 16 and the rotating electrical machine 12 according to the operating state of the engine 10 acquired based on the outputs of various sensors such as the crank angle sensor 33. More specifically, regarding the drive control of the rotating electrical machine 12, negative torque applying control for causing the rotating electrical machine 12 to perform a negative torque applying function, power running control for causing the rotating electrical machine 12 to execute a power running function, and standby function for the rotating electrical machine 12. The control is selected from among the standby control for executing the control and the selected control is executed. For this reason, ECU30 corresponds to a rotary electric machine control part. The ECU 30 corresponds to a stop crank angle acquisition unit, a restart unit, a rotation speed calculation unit, and a rotation angle estimation unit.

  By the way, at the time of restart after the automatic stop, the engine 10 needs to be started as soon as possible. Therefore, by controlling the intake throttle valve during the engine stop control, the engine 10 is preferably set to the piston stop position of a cylinder (hereinafter referred to as the first cylinder) that becomes the compression stroke when the engine 10 is stopped among the plurality of cylinders. The control (hereinafter referred to as piston stop position control) in which the first fuel combustion is started in the first cylinder as a whole of the engine 10 within the range in which the engine can be restarted (hereinafter referred to as a predetermined range). It has been implemented.

  However, if the intake throttle valve is controlled to open when the engine 10 is stopped, the compression reaction force in the cylinder increases. As a result, as indicated by the solid line in FIG. 2, the rotational speed of the crankshaft 11 pulsates more greatly than when the intake throttle valve is controlled in the closing direction (dotted line in FIG. 2), and the engine 10 is stopped. There is a concern that the vibration of the engine 10 that sometimes occurs becomes large. For this reason, when the piston stop position control is performed, it is considered that there is a limit on the amount of opening that drives the intake throttle valve in the opening direction. At this time, depending on the size of the restriction, the controllability of the piston stop position of the first cylinder may be reduced.

  On the other hand, the engine 10 has a resonance region of rotational vibration. When the engine 10 is restarted to suppress the vibration of the engine 10, the cylinder that reaches the compression top dead center next to the first cylinder (hereinafter referred to as the first cylinder). It is desirable that the rotational speed of the crankshaft 11 pass through the resonance region by the combustion of fuel by two-cylinder (refer to time t3-t4 in FIG. 3, for example). However, when the piston stop position control is performed, the above-described concern occurs, and when the piston stop position of the first cylinder when the engine 10 is automatically stopped is out of a predetermined range, the engine 10 is automatically stopped. There is a possibility that the period during which the rotational speed of the crankshaft 11 exists in the resonance region when the engine 10 is restarted may be longer than when the piston stop position of the first cylinder falls within a predetermined range. .

  For example, when the stop crank angle as the crank angle in the state where the engine 10 is automatically stopped is smaller than the first threshold in the forward rotation direction of the crankshaft 11, the stop crank angle is larger than the first threshold. Thus, the piston stop position of the first cylinder is on the bottom dead center side, and the time until the first cylinder reaches the compression top dead center after a predetermined restart condition is satisfied becomes longer. That is, there is a possibility that the rotational speed of the crankshaft 11 becomes excessively high due to the torque application by the starter motor 16 before the first cylinder reaches the compression top dead center. In this case, if the engine 10 (first cylinder) performs fuel combustion, the rotational speed of the crankshaft 11 may enter the resonance region due to the rotational torque generated at that time, as indicated by the dotted line in FIG. Time t12-t33).

  Further, when the stop crank angle is larger than the second threshold value set larger than the first threshold value, the piston stop position of the first cylinder is higher than when the stop crank angle is smaller than the second threshold value. It is on the dead center side, and the time from when a predetermined restart condition is established until the first cylinder reaches the compression top dead center is shortened. When restart control of the engine 10 is performed in this situation, the rotational speed of the crankshaft 11 is increased to a rotational speed at which the engine can be started by combustion of fuel before the first cylinder reaches the compression top dead center. It may not be possible to In such a case, since the first fuel cannot be burned in the first cylinder after the predetermined restart condition is satisfied, the first fuel is burnt in the second cylinder as a whole engine. It will be. At this time, the rotation speed of the crankshaft 11 is lower as shown by the dotted line in FIG. 5 compared to the case where the fuel is burned in the second cylinder after the fuel is burned in the first cylinder (see FIG. 3). Under certain circumstances, the combustion of fuel by the second cylinder will be performed. Therefore, in the fuel combustion of the second cylinder in the above situation, it is impossible to prevent the rotation speed of the crankshaft 11 from passing back through the resonance range, and the rotation speed of the crankshaft 11 enters the resonance range a plurality of times. There is a possibility that the vibration of the engine becomes large during that period (see time t23-t34).

  As a countermeasure, the ECU 30 acquires a stop crank angle from the crank angle sensor 33 when the engine 10 is automatically stopped. In the automatic restart, power running control is performed based on the stop crank angle acquired from the crank angle sensor 33 during a period from when a predetermined restart condition is satisfied to the second compression top dead center of the plurality of cylinders. Then, one of the negative torque application control and the standby control is selected and executed.

  Specifically, when the stop crank angle acquired by the crank angle sensor 33 is larger than the first threshold and smaller than the second threshold, the piston stop position of the first cylinder stops within a predetermined range. It is thought that. Therefore, when a predetermined restart condition is satisfied in the above situation, the normal restart of the engine 10 is possible without the rotating electrical machine 12 applying negative torque or positive torque to the crankshaft 11. Thus, it is possible to increase the rotational speed of the crankshaft 11 so as to pass through the resonance region as soon as possible. Therefore, in the above situation, standby control is selected and executed.

  On the condition that the stop crank angle acquired from the crank angle sensor 33 is smaller than the first threshold value, the negative torque application control is selected, and the second compression top dead of the plurality of cylinders after the predetermined restart condition is satisfied. Negative torque application control is performed during the period up to the point.

  Further, when the stop crank angle acquired by the crank angle sensor 33 is larger than the second threshold value, the power running control is selected, and after the predetermined restart condition is satisfied, the second compression top dead of the plurality of cylinders. Power running control is performed during the period up to the point.

  By the way, in order to drive the rotating electrical machine 12 appropriately, it is necessary to recognize the rotation angle of the rotor constituting the rotating electrical machine 12. In this respect, in the present embodiment, the MOS-Alt assumed as the rotating electrical machine 12 is not provided with a detection sensor for detecting the rotational angle position of the rotor (not shown). The rotational angle position is estimated from the induced voltage and back electromotive force generated in the rotor or stator provided.

  However, when the rotational speed of the crankshaft 11 is low, the induced voltage and the counter electromotive force generated in the rotor or the stator are lowered, and accordingly, it is assumed that the estimation accuracy of the rotation angle of the rotor is lowered. . If the estimation method is performed in this situation, the estimation accuracy of the rotational angle position of the rotor is lowered, and there is a possibility that the rotating electrical machine 12 cannot be driven appropriately depending on the situation. Considering this, the lower limit value of the rotational speed of the crankshaft 11 that may not be able to drive the rotating electrical machine 12 properly due to a decrease in the estimation accuracy of the rotation angle of the rotor is set as the estimated threshold value, and the rotation detection unit 23 The rotation angle of the rotor is not estimated in a state where the rotation speed of the crankshaft 11 is lower than the estimated threshold value. At this time, in the automatic restart, there is a possibility that the rotation speed of the crankshaft 11 is lower as it falls below the estimated threshold during the period from when a predetermined restart condition is satisfied to the first compression top dead center of the plurality of cylinders. There is a possibility that the rotating electrical machine 12 cannot be driven appropriately due to a situation in which the rotation angle of the rotor is not estimated.

  Therefore, in the present embodiment, when the negative torque application control is performed on the condition that the stop crank angle acquired from the crank angle sensor 33 is smaller than the first threshold value, the period is set to the first compression on the plurality of cylinders. The period from the dead point to the second compression top dead center of the plurality of cylinders. Further, when the power running control is performed because the stop crank angle acquired by the crank angle sensor 33 is larger than the second threshold value, the period is changed from the first compression top dead center of the plurality of cylinders to the second of the plurality of cylinders. The period until the top compression top dead center. As a result, the rotating electrical machine can be driven in a situation where the rotation speed of the crankshaft 11 is unlikely to be below the estimated threshold value.

  Incidentally, as described above, it is desirable that the rotational speed of the crankshaft 11 passes through the resonance region due to the combustion of fuel by the second cylinder when the engine 10 is restarted in order to suppress vibration of the engine 10. Therefore, the power running control is performed after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached. As a result, not only the rotational torque generated by the combustion of fuel in the second cylinder but also the positive torque is applied to the crankshaft 11 by the rotating electrical machine 12, the degree of increase in the rotational speed of the crankshaft 11 increases, The possibility that the rotation speed can pass without stagnating in the resonance region can be increased.

  Further, in the present embodiment, the drive of the starter motor 16 that is performed when a predetermined restart condition is satisfied is continued until the engine 10 reaches a complete explosion. Thereby, the engine 10 can be started reliably.

  In the present embodiment, the ECU 30 performs the automatic stop / restart control shown in FIG. The automatic stop / restart control shown in FIG. 6 is repeatedly performed at a predetermined cycle by the ECU 30 during a period in which the ECU 30 is powered on.

  First, in step S100, it is determined whether a predetermined automatic stop condition is satisfied. When it is determined that the predetermined automatic stop condition is not satisfied (S100: NO), the process of step S100 is performed again. If it is determined that the predetermined automatic stop condition is satisfied (S100: YES), the process proceeds to step S110.

  In step S110, stop control of the engine 10 is started by stopping fuel supply to the engine 10. In step S120, it is determined whether or not the engine 10 has completely stopped based on whether or not the rotational speed of the crankshaft 11 calculated based on the crank angle detected by the crank angle sensor 33 is lower than the first determination value. . The first determination value is a value provided to identify that the rotation speed of the crankshaft 11 has become zero. If it is determined that the engine 10 is not completely stopped (S120: NO), the process of step S120 is performed again. If it is determined that the engine 10 has completely stopped (S120: YES), the process proceeds to step S130.

  In step S130, the stop crank angle is acquired from the crank angle sensor 33. In step S140, it is determined whether a predetermined restart condition is satisfied. When it is determined that the predetermined restart condition is not satisfied (S140: NO), the process of step S140 is performed again. If it is determined that the predetermined restart condition is satisfied (S140: YES), the process proceeds to step S150. In step S150, a restart process for restarting the engine 10 is performed.

  In addition, the process of step S130 corresponds to the process as a stop crank angle acquisition part.

  Moreover, the restart process of FIG. 7 is implemented by ECU30. The restart process shown in FIG. 7 is a subroutine process corresponding to step S150 shown in FIG.

  First, in step S200, the starter motor 16 is driven. In step S210, standby control is performed. In step S220, it is determined whether or not the stop crank angle acquired in step S130 is smaller than the first threshold value. If it is determined that the stop crank angle is smaller than the first threshold (S220: YES), the process proceeds to step S230.

  In step S230, the first cylinder has reached the compression top dead center depending on whether or not the crank angle position acquired from the crank angle sensor 33 is an angle position indicating that the first cylinder has reached the compression top dead center. It is determined whether or not. When it is determined that the first cylinder has not reached the compression top dead center (S230: NO), step S230 is performed again. When it is determined that the first cylinder has reached compression top dead center (S230: YES), the process proceeds to step S240. In step S240, standby control is terminated and negative torque application control is performed.

  In step S250, the second cylinder has reached the compression top dead center depending on whether or not the crank angle position acquired from the crank angle sensor 33 is an angle position indicating that the second cylinder has reached the compression top dead center. It is determined whether or not. When it is determined that the second cylinder has not reached compression top dead center (S250: NO), step S250 is performed again. If it is determined that the second cylinder has reached compression top dead center (S250: YES), the process proceeds to step S260, and the negative torque application control is terminated. In step S270, power running control is performed.

  In step S280, it is determined whether or not the engine 10 has been started (completely exploded) based on whether or not the rotational speed of the crankshaft 11 has become higher than the second determination value. The second determination value is set to a rotation speed at which the engine 10 can be driven independently. When it is determined that the engine 10 has not been started (S280: NO), step S280 is performed again. When it is determined that the engine 10 has been started (S280: YES), the process proceeds to step S290, power running control is terminated, and standby control is performed. In step S300, the drive of the starter motor 16 is terminated. And this control is complete | finished.

  When it is determined that the stop crank angle is larger than the first threshold (S220: NO), the process proceeds to step S310. In step S310, it is determined whether or not the stop crank angle is smaller than a second threshold value. If it is determined that the stop crank angle is smaller than the second threshold (S310: YES), the process proceeds to step S320.

  In step S320, it is determined whether or not the second cylinder has reached compression top dead center by the same method as in step S250. When it is determined that the second cylinder has not reached the compression top dead center (S320: NO), step S320 is performed again. When it is determined that the second cylinder has reached compression top dead center (S320: YES), the process proceeds to step S270.

  When it is determined that the stop crank angle is larger than the second threshold (S310: YES), the process proceeds to step S330. In step S330, it is determined whether or not the first cylinder has reached compression top dead center by the same method as in step S230. If it is determined that the first cylinder has not reached the compression top dead center (S330: NO), step S330 is performed again. When it is determined that the first cylinder has reached compression top dead center (S330: YES), the process proceeds to step S270.

  Step S200 corresponds to processing as a restarting unit, and processing of steps S210 to 270 and steps S310 to 330 corresponds to processing as a rotating electrical machine control unit.

  Next, with reference to FIGS. 3-5, the aspect of the restart control concerning this embodiment is demonstrated.

  FIG. 3 assumes a case where the stop crank angle acquired by the crank angle sensor 33 is larger than the first threshold and smaller than the second threshold. In this case, when a predetermined restart condition is satisfied, the starter motor 16 is started to be driven, and a positive torque is applied to the crankshaft 11 to increase the rotational speed of the crankshaft 11 (see time t1). At this time, by performing standby control, the rotating electrical machine 12 is made to perform a standby function. When the piston position of the first cylinder reaches the compression top dead center, fuel is supplied to the first cylinder, and the first fuel combustion is started as the entire engine 10 (see time t2).

  Then, when the piston position of the second cylinder reaches the compression top dead center, the second cylinder performs the second fuel combustion as the entire engine 10, while the standby control is ended and the power running control is performed. A positive torque is applied to the crankshaft 11 by the rotating electrical machine 12 (see time t3). The increase in the rotational speed of the crankshaft 11 that occurs at this time passes through the resonance range (see time t3-t4). After that, similarly, fuel is burned by the cylinder while a positive torque is applied to the crankshaft 11 by the rotating electrical machine 12. Then, when the rotational speed of the crankshaft 11 becomes higher than the second determination value, it is recognized that the engine 10 has completely exploded, and the power running control is terminated and the drive of the starter motor 16 is stopped (see time t5). . The starter motor 16 continues to drive for a period from when a predetermined restart condition is satisfied until the engine 10 completes explosion (see time t1-t5).

  The control shown in FIG. 4 will be described focusing on the differences from the control shown in FIG. FIG. 4 assumes a case where the stop crank angle acquired by the crank angle sensor 33 is smaller than the first threshold value. Therefore, the rotational speed of the crankshaft 11 when the first cylinder reaches the compression top dead center is higher than the rotational speed of the crankshaft 11 at the same point in FIG. 3 (see time t12). For this reason, when the first cylinder reaches compression top dead center, the first electric cylinder performs fuel combustion, finishes standby control, and performs negative torque application control, whereby the rotating electrical machine 12 performs cranking. A negative torque is generated with respect to the shaft 11 (see time t12-13). The other control is the same as that in FIG.

  The control shown in FIG. 5 will be described focusing on the differences from the control shown in FIG. FIG. 5 assumes a case where the stop crank angle acquired by the crank angle sensor 33 is larger than the second threshold value. Therefore, the rotational speed of the crankshaft 11 when the first cylinder reaches the compression top dead center is lower than the rotational speed of the crankshaft 11 at the same point in FIG. 3 (see time t22). Therefore, when the first cylinder reaches the compression top dead center, the combustion of the fuel is performed in the first cylinder, the standby control is terminated, and the power running control is performed. Torque is applied (see time t22-23). The other control is the same as that in FIG.

  With this configuration, the present embodiment has the following effects.

  The negative torque application control is selected on the condition that the stop crank angle acquired by the crank angle sensor 33 is smaller than the first threshold, and the second of the plurality of cylinders from the first compression top dead center of the plurality of cylinders is selected. Negative torque application control is performed during the period up to the compression top dead center. Thereby, the rotational speed of the crankshaft 11 during the period from the first compression top dead center of the plurality of cylinders to the second compression top dead center of the plurality of cylinders can be suppressed low. As a result, when the fuel is burned in the first cylinder, the possibility that the rotation speed of the crankshaft 11 enters the resonance region can be suppressed.

  When the stop crank angle acquired by the crank angle sensor 33 is larger than the second threshold value, the power running control is selected, and the second compression top dead of the plurality of cylinders from the first compression top dead center of the plurality of cylinders. Power running control is performed during the period up to the point. Thereby, the rotation speed of the crankshaft 11 can be sufficiently increased by the time when the fuel is burned in the second cylinder so that the fuel passes through the resonance region as soon as the fuel is burned by the second cylinder.

  The above embodiment can also be implemented with the following modifications.

  In the above embodiment, the rotating electrical machine 12 is not equipped with a detection sensor that detects the rotational angle position of the rotor. In this regard, the rotating electrical machine 12 may be provided with a detection sensor that detects the rotational angle position of the rotor. In this case, the rotational angle of the rotor can be detected even if the rotational speed of the crankshaft 11 is lower than the estimated threshold value. That is, power running control can be performed in a period from when a predetermined restart condition is satisfied to the first compression top dead center of a plurality of cylinders. Therefore, when the rotating electrical machine 12 is provided with a detection sensor that detects the rotational angle position of the rotor, power running is performed during a period from when a predetermined restart condition is satisfied until the second compression top dead center of the plurality of cylinders. Control may be implemented. Similarly, when the rotating electrical machine 12 is provided with a detection sensor that detects the rotational angle position of the rotor, during a period from when a predetermined restart condition is satisfied to the second compression top dead center of a plurality of cylinders. Negative torque application control may be performed.

  In the above embodiment, the rotating electrical machine 12 is assumed to be MOS-Alt. In this regard, the rotating electrical machine 12 may be an ISG (Integrated Starter Generator).

  Alternatively, the rotating electrical machine 12 may be an alternator having only a negative torque applying function. In this case, since the power running control cannot be performed, only the control when the stop crank angle is smaller than the first threshold value is performed.

  FIG. 8 is a flowchart in the case where the restart control is performed using an alternator having only a negative torque imparting function, and a part of the flowchart of FIG. 7 is modified. That is, steps S270, S290, and S310-S330 in FIG. 7 are deleted. Further, step S260 in FIG. 7 is deleted, and step S460 is added instead. In the added step S460, the negative torque application control is terminated and standby control is performed.

  For the other steps, the processes in steps S400, 410, 420, 430, 440, 450, 480, and 500 in FIG. 8 are respectively performed in steps S200, 210, 220, 230, 240, 250, and 250 in FIG. This is the same as the processing of 280 and 300.

  In the above embodiment, when the engine 10 is automatically stopped, the stop crank angle is acquired from the crank angle sensor 33 before the predetermined restart condition is satisfied. With respect to this, the stop crank angle may be acquired from the crank angle sensor 33 during a period from when a predetermined restart condition is satisfied until the starter motor 16 is driven.

  In the above embodiment, the power running control is performed after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached. With respect to this, it is not necessary to perform the power running control after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached. In this case, the power running control performed when the stop crank angle is larger than the second threshold is performed only during the period from the first compression top dead center of the plurality of cylinders to the second compression top dead center of the plurality of cylinders. Shall be done.

  In the above embodiment, the starter motor 16 continues to be driven for a period from when a predetermined restart condition is satisfied until the engine 10 is completely exploded. In this regard, the driving of the starter motor 16 may be stopped when the power running control is performed after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached. Thereby, compared with the case where the drive of the starter motor 16 is continued until the engine 10 reaches a complete explosion, the noise and vibration by the starter motor 16 can be suppressed.

  In the above embodiment, in the automatic restart, based on the stop crank angle acquired from the crank angle sensor 33 during a period from when a predetermined restart condition is satisfied to the second compression top dead center of the plurality of cylinders. One of the power running control, the negative torque application control, and the standby control is selected and executed. In this regard, for example, based on the stop crank angle acquired from the crank angle sensor 33, one of power running control and negative torque application control may be selected and executed. Or based on the stop crank angle acquired from the crank angle sensor 33, you may select and implement one control among power running control and standby control.

  In the above embodiment, the negative torque application control is performed on the condition that the stop crank angle is smaller than the first threshold value. By the negative torque application control performed at this time, the magnitude of the negative torque applied to the crankshaft 11 by the rotating electrical machine 12 may be controlled to increase as the stop crank angle is at the bottom dead center side. .

  On the other hand, power running control is performed on condition that the stop crank angle is larger than the second threshold. By the power running control performed at this time, the magnitude of the positive torque applied to the crankshaft 11 by the rotating electrical machine 12 may be controlled to increase as the stop crank angle is on the top dead center side.

  By performing the control in this other example, it is ensured that the rotation speed of the crankshaft 11 increases monotonously until reaching the resonance range of the engine 10 and then returns to the resonance range. Can be realized.

  In the above embodiment, the ECU 30 selects any one of negative torque application control, power running control, and standby control, and the selected control is performed. In this regard, for example, the control IC provided in the rotating electrical machine 12 may select any one of negative torque application control, power running control, and standby control, and execute the selected control. In this case, the stop crank angle is transmitted from the ECU 30 to the control IC via the communication network.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Crankshaft, 12 ... Rotary electric machine, 30 ... ECU, 33 ... Crank angle sensor.

Claims (10)

An engine (10) having a plurality of cylinders, a rotating electrical machine (12) provided to be able to transmit torque to the crankshaft (11) of the engine, and a crank angle sensor (33) for detecting a crank angle of the crankshaft A restart control device (30) that is applied to a vehicle that performs automatic restart of the engine on condition that a predetermined restart condition is satisfied while automatically stopping the engine. And
A stop crank angle acquisition unit that acquires from the crank angle sensor a stop crank angle that is the crank angle in a state where the engine is automatically stopped;
Based on the stop crank angle acquired by the stop crank angle acquisition unit during a period from the establishment of the predetermined restart condition in the automatic restart to the second compression top dead center of the plurality of cylinders, Power running control for applying positive torque to the crankshaft by the rotating electrical machine, negative torque applying control for applying negative torque to the crankshaft by the rotating electrical machine, and standby control for waiting for the power running control and the negative torque applying control And a rotating electrical machine control unit that selects and implements one control from at least two controls,
A restart control device comprising: The rotating electrical machine can apply the negative torque to the crankshaft,
The rotating electrical machine control unit selects the negative torque application control on the condition that the stop crank angle acquired by the stop crank angle acquisition unit is smaller than a first threshold in the positive rotation direction of the crankshaft. The restart control device according to claim 1 to be implemented. The rotating electrical machine can wait for the application of the negative torque to the crankshaft and the application of the positive torque to the crankshaft,
The rotating electrical machine control unit is set such that the stop crank angle acquired by the stop crank angle acquisition unit is larger than the first threshold value and larger than the first threshold value in the positive rotation direction of the crankshaft. The restart control device according to claim 1 or 2, wherein the standby control is selected and executed when the second threshold value is smaller than the second threshold value. The rotating electrical machine can apply the positive torque to the crankshaft,
The rotating electrical machine control unit, when the stop crank angle acquired by the stop crank angle acquisition unit is larger than a second threshold set larger than the first threshold in the positive rotation direction of the crankshaft, The restart control device according to claim 2 or 3, wherein the power running control is selected and executed.   The rotating electrical machine control unit selects the crankshaft so that the rotation speed of the crankshaft increases monotonously until it reaches the resonance range of the engine and then exits from the resonance range, and does not return to the resonance range. The restart control device according to claim 1, wherein the control is performed. A rotational speed calculation unit that calculates the rotational speed of the crankshaft based on the crank angle detected by the crank angle sensor;
The rotational angle of the rotating electrical machine is estimated when the rotational speed of the crankshaft calculated by the rotational speed calculating unit is higher than an estimated threshold, and the rotational angle of the rotating electrical machine is lower than the estimated threshold. A rotation angle estimation unit that does not estimate
With
5. The restart control according to claim 4, wherein the rotating electrical machine control unit performs the power running control during a period from a first compression top dead center of the plurality of cylinders to a second compression top dead center of the plurality of cylinders. apparatus.   The rotating electrical machine control unit performs the power running control after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached. Restart controller. The vehicle includes a starter (16) for starting the engine,
8. The restart control device according to claim 1, further comprising a restart unit configured to rotate the crankshaft by the starter and restart the engine when the predetermined restart condition is satisfied. The rotating electrical machine control unit causes the power running control to be performed after the predetermined restart condition is satisfied and the second compression top dead center of the plurality of cylinders is reached,
The restarting unit stops driving of the starter when the powering control is performed after the rotating electrical machine control unit has reached the second compression top dead center of the plurality of cylinders. The restart control device described.   The restart control device according to claim 8, wherein the restart unit continues driving the starter until the engine reaches a complete explosion.

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