JP6764337B2 - Restart controller - Google Patents

Description

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

In recent years, for example, a vehicle equipped with 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 when restarting after idling stop, an early start of the engine is required. .. Therefore, in order to improve the responsiveness of engine restart, for example, the technique disclosed in Patent Document 1 is being 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 degree 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 when stopped), the last top dead center of all cylinders before the engine is stopped (hereinafter, referred to as The intake throttle valve is driven in the open direction when passing the top dead center immediately before (referred to as 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 stop stops in the compression stroke without exceeding the top dead center. Here, if the stop position of the piston falls within the specific range set between the top dead center and the bottom dead center, the compression stroke cylinder at the time of stop can start the first fuel combustion of the entire engine, and the engine can be started. It is said that it can be restarted quickly.

Japanese Unexamined Patent Publication No. 2013-113161

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 is stopped, the compression reaction force in the cylinder increases, and as a result, the engine is stopped. There is a concern that the engine vibration that sometimes occurs will increase. Therefore, when the automatic stop control described in Patent Document 1 is implemented, it is considered that a limit is provided on the amount of opening that drives the intake throttle valve in the opening direction, and depending on the magnitude of the limit, the compression stroke at the time of stop. The controllability of the piston stop position of the cylinder may decrease.

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 the vibration of the engine. However, when the above-mentioned concern arises when the automatic stop control described in Patent Document 1 is performed, and the piston stop position of the compression stroke cylinder at the time of stop when the engine is automatically stopped deviates from the specific range, the engine When the engine is automatically stopped, the compression stroke when the engine is stopped The piston stop position of the cylinder is within a specific range, and the engine rotation speed when the engine is restarted is longer in the resonance region. there is a possibility. In this case, the vibration of the engine when the engine is restarted becomes large.

The present invention has been made to solve the above problems, and a main object thereof is the rotation speed of the crankshaft so as to quickly pass through the resonance region without depending on the rotation angle position of the crankshaft when the engine is stopped. It is an object of the present invention to provide a restart control device capable of raising the speed.

The present invention includes an engine having a plurality of cylinders, a rotary electric machine provided so as to be able to transmit torque to each other with the crankshaft of the engine, and a crank angle sensor for detecting the crank angle of the crank shaft, and the engine is automatically operated. A restart control device applied to a vehicle that automatically restarts the engine on condition that a predetermined restart condition is satisfied while stopping the engine, in a state where the engine is automatically stopped. The stop crank angle acquisition unit that acquires the stop crank angle, which is the crank angle, from the crank angle sensor, and the second compression top death of the plurality of cylinders after the predetermined restart condition is satisfied in the automatic restart. In the period up to the point, based on the stop crank angle acquired by the stop crank angle acquisition unit, the rotary electric machine applies a positive torque to the crankshaft, and the rotary electric machine negatively applies the crankshaft. It includes a rotary electric machine control unit that selects and executes one control from at least two of the negative torque applying control for applying torque, the power running control and the standby control for waiting for the negative torque applying control. ..

If the intake throttle valve is controlled in the open direction when the engine is stopped, there is a concern that the engine vibration that occurs when the engine is stopped will increase. Therefore, when performing piston stop position control, the amount of opening that drives the intake throttle valve in the open direction is limited. Is considered to be provided. At this time, depending on the magnitude of the limitation, the controllability of the piston stop position of the cylinder (hereinafter referred to as the first cylinder) that is in the compression stroke when the engine is stopped may be deteriorated among the plurality of cylinders. If the above concern arises when the piston stop position control is performed, the rotation speed of the crankshaft may exist in the resonance region for a long time, and the engine vibration at the time of restarting the engine may increase.

As a countermeasure, the stop crank angle is acquired from the crank angle sensor. Then, in the automatic restart, during the period from the establishment of the predetermined restart condition to the second compression top dead center of the plurality of cylinders, the power running control is performed based on the stop crank angle acquired by the stop crank angle acquisition unit. , Negative torque application control and standby control, one control is selected and implemented from at least two controls. 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, from the time when the predetermined restart condition is satisfied to the second compression top dead center of the plurality of cylinders. By appropriately adjusting the rotation speed of the crankshaft by the rotary electric machine during the period, it is possible to increase the rotation speed of the crankshaft so as to quickly pass through the resonance region.

In the second invention, in the first invention, the rotary electric machine can apply a negative torque to the crankshaft, and the rotary electric machine control unit has the stop crank angle acquired by the stop crank angle acquisition unit. Is smaller than the first threshold value in the forward rotation direction of the crankshaft, and the negative torque application control is selected and implemented.

The situation where the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is smaller than the first threshold value is the case where the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is larger than the first threshold value. In comparison, the piston stop position of the first cylinder is on the bottom dead center side, which means that it takes a long time for the first cylinder to reach the compression top dead center after the predetermined restart condition is satisfied. .. Therefore, the rotation speed of the crankshaft when the first cylinder reaches the compression top dead center is higher than that in the case where the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is larger than the first threshold value. It is assumed that it has become a thing. At this time, if the engine (first cylinder) is made to burn fuel, the rotational speed of the crankshaft may fall within the resonance region due to the rotational torque generated at that time. As a countermeasure, the second compression top dead of the plurality of cylinders after the predetermined restart condition is satisfied, provided that the stop crank angle of the crankshaft acquired by the stop crank angle acquisition unit is smaller than the first threshold value. Negative torque application control is selected and implemented during the period up to the point. As a result, the rotation speed of the crankshaft when the first cylinder reaches the compression top dead center can be suppressed to a low level, and when the engine (first cylinder) is made to burn fuel, the rotation speed of the crankshaft is suppressed. Can be kept low in the possibility that

According to the third invention, in the first or second invention, the rotary electric machine can wait for the negative torque to be applied to the crankshaft and the positive torque to be applied to the crankshaft. In the rotary electric machine control unit, when the stop crank angle acquired by the stop crank angle acquisition unit is larger than the first threshold value and smaller than the second threshold value set larger than the first threshold value. , The standby control is selected and implemented.

When the stop crank angle acquired by the stop crank angle acquisition unit is larger than the first threshold value and smaller than the second threshold value set larger than the first threshold value, the piston stop position of the first cylinder is set. It is considered that the engine is stopped within a range (specific range) where the engine can be restarted suitably. Therefore, when a predetermined restart condition is satisfied in the above situation, resonance occurs in a normal engine restart even if the rotary electric machine does not apply negative torque or positive torque to the crankshaft. It is possible to increase the rotational speed of the crankshaft so that it passes through the range quickly.

According to a fourth aspect of the present invention, in the second or third invention, the rotary electric machine can apply the positive torque to the crankshaft, and the rotary electric machine control unit is acquired by the stop crank angle acquisition unit. When the stop crank angle is larger than the second threshold value set larger than the first threshold value, the force running control is selected and implemented.

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 implemented in this situation, the rotation speed of the crankshaft should be increased to a rotation speed at which the engine can be started by burning fuel by the time the first cylinder reaches the compression top dead center. May not be possible. In such a case, since the first cylinder cannot be made to burn the fuel for the first time after the predetermined restart condition is satisfied, the cylinder that reaches the compression top dead center next (hereinafter, the second cylinder). Fuel is burned in the cylinder). At this time, compared to the case where the fuel is burned in the first cylinder and then the fuel is burned in the second cylinder, the fuel is burned by the second cylinder in a situation where the rotation speed of the crankshaft is lower. 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 through the resonance region and returning, and the rotation speed of the crankshaft enters the resonance region a plurality of times. Period The engine vibration may increase.

As a countermeasure, when the stop crank angle acquired by the stop crank angle acquisition unit is larger than the second threshold value, the period from the establishment of the predetermined restart condition to the second compression top dead center of the plurality of cylinders. Power running control is selected and implemented. As a result, the rotational speed of the crankshaft can be sufficiently increased by the time the fuel is burned in the second cylinder so that the fuel burns in the second cylinder quickly passes through the resonance region.

Fifth invention, in any one of the first to fourth inventions, the rotary electric machine control unit is monotonously until the rotation speed of the crankshaft reaches the resonance region of the engine and then exits the resonance region. The selected control is performed so that it does not rise and return to the resonance region.

By implementing the above control, the rotational speed of the crankshaft does not stagnate in the resonance region, and it is possible to quickly pass through the resonance region.

The sixth invention is calculated by the rotation speed calculation unit for calculating the rotation speed of the crankshaft and the rotation speed calculation unit based on the crank angle detected by the crank angle sensor in the fourth invention. When the rotation speed of the crankshaft is higher than the estimated threshold value, the rotation angle of the rotary electric machine is estimated, and when the rotation speed is lower than the estimated threshold value, the rotation angle of the rotary electric machine is not estimated. The rotary electric machine control unit performs the power running control during the period from the first compression top dead point of the plurality of cylinders to the second compression top dead point of the plurality of cylinders.

In order for the rotary electric machine to apply positive torque to the crankshaft, it is necessary to correctly recognize the rotation angle of the rotary electric machine. In this regard, if a rotation angle sensor for detecting the rotation angle of the rotary electric machine is not provided, it is necessary to estimate the rotation angle of the rotary electric machine. However, it is often difficult to estimate the rotation angle of a rotating electric machine when the rotation speed of the crankshaft is lower than the estimated threshold value. Therefore, during the period from the establishment of the predetermined restart conditions to the first compression top dead center of multiple cylinders, the rotation speed of the crankshaft may be lower as it falls below the estimated threshold value, and power running control is applied to the rotary electric machine. It is considered difficult to carry out normally. Therefore, power running control is performed by the rotary electric machine control unit 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. As a result, power running control can be performed in a situation where the rotation speed of the engine is unlikely to fall below the estimated threshold value.

A seventh aspect of the invention is the invention of any one of the first to sixth aspects, after the rotary electric machine control unit reaches the second compression top dead center of the plurality of cylinders after the predetermined restart condition is satisfied. , The power running control is carried out.

The scene where the rotational speed of the crankshaft passes through the resonance region is often 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 by the second cylinder but also the positive torque is applied to the crankshaft by the rotary electric machine, so that the degree of increase in the rotational speed of the crankshaft increases and the rotational speed of the crankshaft resonates. It is possible to increase the possibility of passing through the area without stagnation.

An eighth invention, in any one of the first to seventh inventions, comprises a starter for starting the engine, and the starter rotates the crankshaft when the predetermined restart condition is satisfied. It is provided with a restart unit for restarting the engine.

In the ninth aspect of the invention, in the eighth aspect, the rotary electric 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 restart unit stops the drive of the starter when the power running control is performed after the rotary electric machine control unit reaches the second compression top dead center of the plurality of cylinders.

When a predetermined restart condition is satisfied and a positive torque is applied to the crankshaft by the rotary electric machine after reaching the second compression top dead center of the plurality of cylinders, the starter drive is stopped. As a result, noise and vibration due to the starter can be suppressed as compared with the case where the starter drive is continued until the engine is completely detonated.

In the tenth invention, in the eighth invention, the restarting unit continues to drive the starter until the engine is completely detonated.

By continuing to drive the starter until the engine is completely detonated, the engine can be started reliably.

It is a schematic block diagram of the control system which concerns on this embodiment. It is a figure which shows the state of the pulsation of the rotation speed of a crankshaft generated by performing the control which opens the intake throttle valve when the engine is stopped, and the vibration of an engine. It is a time chart which shows the mode of the restart control which concerns on this embodiment. It is a time chart which shows the mode of the restart control which concerns on this embodiment, and the mode when the restart control is not carried out. It is a time chart which shows the mode of the restart control which concerns on this embodiment, and the mode when the restart control is not carried out. It is a control flowchart which the ECU which concerns on this embodiment carries out. This is the subroutine process of step S150 described in FIG. This is another example of the subroutine processing shown in FIG. 7.

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 meshed with the ring gear 15 of the engine 10 when the engine 10 is started in response to a start command, and a positive torque is applied to the crankshaft 11 from the outside to cause the engine 10 to operate. Start.

The crankshaft 11 of the engine 10 is connected to the rotary electric machine 12. In the present embodiment, the rotary electric machine 12 assumes a belt-driven alternator connected to the crankshaft 11 via a belt. This alternator includes a multi-phase winding and a field winding, and rectifies the AC output current output from the multi-phase winding by a plurality of MOSFETs, and is also called MOS-Alt. By controlling this MOSFET, the rotary electric machine 12 as a MOS-Alt can have a power running function in addition to a negative torque applying function of applying a negative torque to the crankshaft 11. The power running function applies positive torque to the crankshaft 11 from the outside after warming up such as idling stop restart (restart from automatic engine stop) and when the engine 10 is started until it completely explodes. It is a function. Further, the rotary electric machine 12 has a standby function of waiting for the execution of the negative torque applying function and the power running function. The rotary electric machine 12 is connected to the ECU 30 by 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, in a cycle of 30 ° CA).

The control system 100 includes a rotary electric machine 12, a starter motor 16, an ECU 30, an electric load 13, and a lead storage battery 14.

The lead storage battery 14 is a well-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). Then, a plurality of battery cells composed of these electrodes are connected in series. The lead-acid battery 14 is electrically connected to the starter motor 16 via a relay 20 in parallel by a feeding line 15 as a connecting line.

The relay 20 is connected by the drive signal from the ECU 30. When the engine 10 is started according to the start command, the ECU 30 transmits a drive signal to the relay 20, and when the relay 20 is connected, the starter motor 16 is rotated by the electric power supplied from the lead-acid battery 14. As a result, a positive torque is applied to the crankshaft 11 from the outside to start the engine 10. The same control is performed even when the engine 10 is restarted from the state in which the engine 10 is automatically stopped. On the other hand, when the relay 20 is in the cutoff state, the power supply from the lead storage battery 14 is stopped, and the starter motor 16 is in the non-driving state.

The electric load 13 is a general electric load, and specific examples thereof include a headlight, a wiper such as a front windshield, a blower fan of an air conditioner, a heater for a defroster of a rear windshield, and the like. The electric load 13 is electrically connected in parallel with each of the rotary electric machine 12 and the lead storage battery 14 by a feeder line 15, whereby power is supplied from the rotary electric machine 12 and the lead storage battery 14 to the electric 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 well-known electronic control device including a microcomputer and the like.

The ECU 30 causes the engine 10 to automatically stop when a predetermined automatic stop condition is satisfied while the vehicle is running. Then, when the automatic stop of the engine 10 is executed and the predetermined restart condition is satisfied, the engine 10 is automatically restarted. The automatic stop conditions include, for example, that the vehicle speed is equal to or less than a predetermined value, and that the accelerator operation amount detected by the accelerator sensor (not shown) is zero (or the brake detected by the brake sensor (not shown)). The amount of operation is larger than the first predetermined amount) and the like are included. Further, the predetermined restart conditions include, 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 rotary electric 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 rotary electric machine 12, the negative torque applying control for causing the rotary electric machine 12 to execute the negative torque applying function, the power running control for causing the rotating electric machine 12 to execute the power running function, and the standby function for the rotating electric machine 12 Select one of the standby control to execute the control, and execute the selected control. Therefore, the ECU 30 corresponds to the rotary electric machine control unit. Further, 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 restarting after automatic stop, the engine 10 is required to start quickly. Therefore, by controlling the intake throttle valve during the engine stop control, the engine 10 is suitable for the piston stop position of the cylinder (hereinafter referred to as the first cylinder) that becomes the compression stroke when the engine 10 is stopped among the plurality of cylinders. Control (hereinafter referred to as piston stop position control) that allows the first cylinder to start the first fuel combustion of the entire engine 10 within the range that can be restarted (hereinafter referred to as the predetermined range) has been conventionally performed. It has been implemented.

However, if the intake throttle valve is controlled in the opening direction when the engine 10 is stopped, the compression reaction force in the cylinder increases. As a result, as shown by the solid line in FIG. 2, the rotation speed of the crankshaft 11 pulsates significantly as compared with the case where 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 will increase. Therefore, when the piston stop position control is performed, it is considered that the opening amount for driving the intake throttle valve in the opening direction is limited. At this time, depending on the size of the limitation, the controllability of the piston stop position of the first cylinder may decrease.

On the other hand, the engine 10 has a resonance region of rotational vibration, and 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, the first cylinder). It is desirable that the rotational speed of the crankshaft 11 passes through the resonance region due to the combustion of fuel by the two cylinders (referred to as two cylinders) (see, for example, time t3-t4 in FIG. 3). However, when the above-mentioned concern arises when the piston stop position control is performed and the piston stop position of the first cylinder when the engine 10 is automatically stopped is out of the predetermined range, the engine 10 is automatically stopped. Compared with the case where the piston stop position of the first cylinder is within the predetermined range, the rotation speed of the crankshaft 11 when the engine 10 is restarted may be longer in the resonance region. ..

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 value in the forward rotation direction of the crankshaft 11, it is compared with the case where the stop crank angle is larger than the first threshold value. Then, the piston stop position of the first cylinder is on the bottom dead center side, and the time from when a predetermined restart condition is satisfied until the first cylinder reaches the compression top dead center becomes long. That is, by the time the first cylinder reaches the compression top dead center, the rotational speed of the crankshaft 11 may become excessively high due to the torque applied by the starter motor 16. In this case, if the engine 10 (first cylinder) is made to burn fuel, the rotational speed of the crankshaft 11 may fall within the resonance region due to the rotational torque generated at that time, as shown by the dotted line in FIG. See time t12-t33).

Further, when the stop crank angle is larger than the second threshold 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 satisfied until the first cylinder reaches the compression top dead center is shortened. When the restart control of the engine 10 is executed in this situation, the rotation speed of the crankshaft 11 is increased to the rotation speed at which the engine can be started by the combustion of fuel by the time the first cylinder reaches the compression top dead center. It may not be possible to let it. In such a case, since it is not possible to cause the first cylinder to burn the fuel for the first time after the predetermined restart condition is satisfied, the combustion of the first fuel for the entire engine is started in the second cylinder. It will be. At this time, the rotation speed of the crankshaft 11 is lower as shown by the dotted line in FIG. 5, as compared with the case where the fuel is burned in the first cylinder and then the fuel is burned in the second cylinder (see FIG. 3). In the situation, fuel will be burned by the second cylinder. Therefore, in the fuel combustion of the second cylinder in the above situation, the rotational speed of the crankshaft 11 cannot be prevented from passing through the resonance region and returning, and the rotational speed of the crankshaft 11 enters the resonance region a plurality of times. During that period, the vibration of the engine may increase (see time t23-t34).

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

Specifically, when the stop crank angle acquired by the crank angle sensor 33 is larger than the first threshold value and smaller than the second threshold value, the piston stop position of the first cylinder stops within a predetermined range. It is thought that it is. Therefore, when the predetermined restart condition is satisfied in the above situation, the normal engine 10 is restarted even if the rotary electric machine 12 does not apply a negative torque or a positive torque to the crankshaft 11. Therefore, 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 implemented.

Negative torque application control is selected on condition that the stop crank angle acquired from the crank angle sensor 33 is smaller than the first threshold value, and after the predetermined restart condition is satisfied, the second compression top dead of the plurality of cylinders. 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, power running control is selected, and after a 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 properly drive the rotary electric machine 12, it is necessary to recognize the rotation angle of the rotors constituting the rotary electric machine 12. In this regard, in the present embodiment, the MOS-Alt assumed as the rotary electric machine 12 is not provided with a detection sensor for detecting the rotation angle position of the rotor (not shown), so that the ECU 30 is installed in the rotary electric machine 12. The rotation angle position is estimated from the induced voltage and countercurrent force generated in the rotor or stator provided.

However, when the rotation speed of the crankshaft 11 is low, it is assumed that the induced voltage and counter electromotive force generated in the rotor or the stator become low, and the estimation accuracy of the rotation angle of the rotor is lowered accordingly. .. If the above estimation method is carried out in this situation, the estimation accuracy of the rotation angle position of the rotor is lowered, and in some cases, the rotary electric machine 12 may not be properly driven. In consideration of this, the lower limit of the rotation speed of the crank shaft 11 which may not be able to drive the rotary electric machine 12 properly due to the decrease in the estimation accuracy of the rotation angle of the rotor is set as the estimation threshold, and the rotation detection unit 23 sets the lower limit value. , The rotation angle of the rotor is not estimated when the rotation speed of the crank shaft 11 is lower than the estimation threshold. At this time, in the automatic restart, the rotation speed of the crankshaft 11 may be lower as it falls below the estimated threshold during the period from the establishment of the predetermined restart condition to the first compression top dead center of the plurality of cylinders. , There is a possibility that the rotary electric machine 12 cannot be properly driven 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 of the plurality of cylinders. The period from the dead center to the second compression top dead center of the plurality of cylinders. Further, when 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 set from the first compression top dead center of the plurality of cylinders to the second of the plurality of cylinders. The period until the second compression top dead center. As a result, the rotary electric machine can be driven in a situation where the rotation speed of the crankshaft 11 is unlikely to fall below the estimated threshold value.

By the way, as described above, it is desirable that the rotation 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 the 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 by the second cylinder but also the positive torque is applied to the crankshaft 11 by the rotary electric machine 12, so that the degree of increase in the rotational speed of the crankshaft 11 increases, and the crankshaft 11 It is possible to increase the possibility that the rotation speed can pass through without stagnation in the resonance region.

Further, in the present embodiment, the driving of the starter motor 16 implemented when a predetermined restart condition is satisfied is continued until the engine 10 is completely detonated. As a result, the engine 10 can be reliably started.

In this embodiment, the ECU 30 implements the automatic stop / restart control shown in FIG. The automatic stop / restart control shown in FIG. 6 is repeatedly executed by the ECU 30 at a predetermined cycle during the period when the power of the ECU 30 is on.

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

In step S110, the stop control of the engine 10 is started by stopping the 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 rotation 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 for identifying that the rotation speed of the crankshaft 11 has become 0. 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 or not the predetermined restart condition is satisfied. If 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.

The process of step S130 corresponds to the process of the stop crank angle acquisition unit.

Further, the restart process of FIG. 7 is performed by the ECU 30. The restart process shown in FIG. 7 is a subroutine process corresponding to step S150 described in FIG.

First, in step S200, the starter motor 16 is driven. In step S210, standby control is performed. Then, 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 value (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. Judge whether or not. If it is determined that the first cylinder has not reached the compression top dead center (S230: NO), step S230 is performed again. If it is determined that the first cylinder has reached the compression top dead center (S230: YES), the process proceeds to step S240. In step S240, the standby control is terminated and the negative torque application control is executed.

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. Judge whether or not. If it is determined that the second cylinder has not reached the compression top dead center (S250: NO), step S250 is performed again. If it is determined that the second cylinder has reached the 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 completed the start (complete explosion) based on whether or not the rotation speed of the crankshaft 11 is 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. If 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, the power running control is terminated, and the standby control is performed. In step S300, the drive of the starter motor 16 is terminated. Then, this control is terminated.

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

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

If it is determined that the stop crank angle is larger than the second threshold value (S310: YES), the process proceeds to step S330. In step S330, it is determined whether or not the first cylinder has reached the compression top dead center in the same manner 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. If it is determined that the first cylinder has reached the compression top dead center (S330: YES), the process proceeds to step S270.

Note that step S200 corresponds to the process as the restart unit, and the processes of steps S210 to 270 and steps S310 to 330 correspond to the process as the rotary electric machine control unit.

Next, a mode of restart control according to the present embodiment will be described with reference to FIGS. 3 to 5.

FIG. 3 assumes a case where the stop crank angle acquired by the crank angle sensor 33 is larger than the first threshold value and smaller than the second threshold value. In this case, when a predetermined restart condition is satisfied, the starter motor 16 is started to be driven, a positive torque is applied to the crankshaft 11, and the rotation speed of the crankshaft 11 is increased (see time t1). At this time, by performing the standby control, the rotary electric machine 12 is made to perform the standby function. Then, 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 of the entire engine 10 is started (see time t2).

Then, when the piston position of the second cylinder reaches the compression top dead center, the second cylinder is made to perform the second fuel combustion of the engine 10 as a whole, while the standby control is terminated and the power running control is performed. The rotary electric machine 12 applies a positive torque to the crankshaft 11 (see time t3). The increase in the rotational speed of the crankshaft 11 that occurs at this time causes the crankshaft to pass through the resonance region (see time t3-t4). After that, similarly, the rotary electric machine 12 applies a positive torque to the crankshaft 11, and the cylinder burns the fuel. Then, when the rotation speed of the crankshaft 11 becomes higher than the second determination value, it is recognized that the engine 10 has completely exploded, 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 be driven for a period from the time when the predetermined restart condition is satisfied until the engine 10 is completely detonated (see time t1-t5).

The control shown in FIG. 4 will be described focusing on the difference from the control shown in FIG. 3 described above. 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 rotation speed of the crankshaft 11 when the first cylinder reaches the compression top dead center is higher than the rotation speed of the crankshaft 11 at the same point in FIG. 3 (see time t12). Therefore, when the first cylinder reaches the compression top dead center, the rotary electric machine 12 cranks the first cylinder by causing the first cylinder to burn fuel, ending the standby control, and performing the negative torque applying control. A negative torque is generated with respect to the shaft 11 (see time t12-13). The other controls are the same as those in FIG.

The control shown in FIG. 5 will be described focusing on the difference from the control shown in FIG. 3 described above. 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 rotation speed of the crankshaft 11 when the first cylinder reaches the compression top dead center is lower than the rotation 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 first cylinder is made to burn fuel, the standby control is terminated, and the power running control is performed, so that the rotary electric machine 12 corrects the crankshaft 11. Torque is applied (see time t22-23). The other controls are the same as those in FIG.

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

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

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

The above embodiment can also be modified and implemented as follows.

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

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

Alternatively, the rotary electric 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 applying function, and is a partially modified version of the flowchart of FIG. 7. 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 in its place. In the added step S460, the negative torque application control is terminated and the standby control is performed.

For the other steps, the processes of steps S400, 410, 420, 430, 440, 450, 480, and 500 in FIG. 8 are the processes of steps S200, 210, 220, 230, 240, 250, respectively in FIG. It 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. Regarding this, the stop crank angle may be acquired from the crank angle sensor 33 during the period from the establishment of the predetermined restart condition to the driving of the starter motor 16.

-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. Regarding this, it is not necessary to perform 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 value is 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. It shall be done.

-In the above embodiment, the starter motor 16 has been continuously driven for a period from the time when the predetermined restart condition is satisfied until the engine 10 is completely detonated. Regarding this, the drive of the starter motor 16 may be stopped when a predetermined restart condition is satisfied and the power running control is executed after reaching the second compression top dead center of the plurality of cylinders. As a result, noise and vibration caused by the starter motor 16 can be suppressed as compared with the case where the engine 10 continues to drive the starter motor 16 until the explosion is completed.

In the above embodiment, in the automatic restart, based on the stop crank angle acquired from the crank angle sensor 33 during the period from the establishment of the predetermined restart condition to the second compression top dead center of the plurality of cylinders. , Power running control, negative torque application control, and standby control were selected and implemented. Regarding this, for example, one of the power running control and the negative torque applying control may be selected and implemented based on the stop crank angle acquired from the crank angle sensor 33. Alternatively, one of the power running control and the standby control may be selected and executed based on the stop crank angle acquired from the crank angle sensor 33.

-In the above embodiment, 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 applying control performed at this time, the magnitude of the negative torque applied to the crankshaft 11 by the rotary electric machine 12 may be controlled so as to increase as the stop crank angle is closer to the bottom dead center side. ..

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

By performing the control in this alternative example, it is ensured that the rotational speed of the crankshaft 11 monotonically increases until it exits the resonance region after reaching the resonance region of the engine 10 and does not return to the resonance region. Can be realized.

In the above embodiment, the ECU 30 selects one of the negative torque application control, the power running control, and the standby control, and the selected control is executed. Regarding this, for example, the control IC provided in the rotary electric machine 12 may be made to select one of the negative torque applying control, the power running control, and the 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.

10 ... engine, 11 ... crankshaft, 12 ... rotary electric machine, 30 ... ECU, 33 ... crank angle sensor.

Claims (11)

An engine (10) having a plurality of cylinders, a rotary electric machine (12) provided so as to be able to transmit torque to each other with the crankshaft (11) of the engine, and a crank angle sensor (33) for detecting the crank angle of the crankshaft. The restart control device (30) is applied to a vehicle that automatically restarts the engine on condition that a predetermined restart condition is satisfied while the engine is automatically stopped. hand,
A stop crank angle acquisition unit that acquires a stop crank angle, which is the crank angle in a state where the engine is automatically stopped, from the crank angle sensor.
Depending on the cylinder that reaches the compression top dead center at the second compression top dead center during the period from the establishment of the predetermined restart condition to the second compression top dead center of the plurality of cylinders in the automatic restart. Positive torque is applied to the crankshaft by the rotary electric machine based on the stop crank angle acquired by the stop crank angle acquisition unit so that the rotation speed of the crankshaft passes through the resonance region of the engine due to fuel combustion. One of at least two controls: a force running control for applying a force running control, a negative torque applying control for applying a negative torque to the crankshaft by the rotating electric machine, and a standby control for waiting for the force running control and the negative torque applying control. The rotary electric machine control unit that selects and executes one control, and
A restart control device. The rotary electric machine can apply the negative torque to the crankshaft.
The rotary electric 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 the first threshold value in the forward rotation direction of the crankshaft. The restart control device according to claim 1. The rotary electric machine can wait for the negative torque to be applied to the crankshaft and the positive torque to be applied to the crankshaft.
In the rotary electric machine control unit, the stop crank angle acquired by the stop crank angle acquisition unit is set to be larger than the first threshold value and larger than the first threshold value in the forward rotation direction of the crankshaft. The restart control device according to claim 2 , wherein the standby control is selected and implemented when the threshold value is smaller than the second threshold value. The rotary electric machine can apply the positive torque to the crankshaft.
When the stop crank angle acquired by the stop crank angle acquisition unit is larger than the second threshold value set to be larger than the first threshold value in the forward rotation direction of the crankshaft, the rotary electric machine control unit is used. The restart control device according to claim 2 or 3, wherein the force running control is selected and implemented. The rotary electric machine control unit is selected so that the rotational speed of the crankshaft monotonically increases until it exits the resonance region after reaching the resonance region of the engine and does not return to the resonance region. The restart control device according to any one of claims 1 to 4, wherein the control is performed. A rotation speed calculation unit that calculates the rotation speed of the crankshaft based on the crank angle detected by the crank angle sensor.
The rotation angle of the rotary electric machine is estimated when the rotation speed of the crank shaft calculated by the rotation speed calculation unit is higher than the estimated threshold value, and the rotation angle of the rotary electric machine is lower than the estimated threshold value. Rotation angle estimation unit that does not estimate
With
The restart control according to claim 4, wherein the rotary electric machine control unit performs the power running control 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. apparatus. An engine (10) having a plurality of cylinders, a rotary electric machine (12) provided so as to be able to transmit torque to the crankshaft (11) of the engine, and a crank angle sensor (33) for detecting the crank angle of the crankshaft. The restart control device (30) is applied to a vehicle that automatically restarts the engine on condition that a predetermined restart condition is satisfied while the engine is automatically stopped. hand,
A stop crank angle acquisition unit that acquires a stop crank angle, which is the crank angle in a state where the engine is automatically stopped, from the crank angle sensor.
Based on the stop crank angle acquired by the stop crank angle acquisition unit during the period from the establishment of the predetermined restart condition to the second compression top dead point of the plurality of cylinders in the automatic restart. Power running control that applies positive torque to the crankshaft by the rotating electric machine, negative torque applying control that applies negative torque to the crankshaft by the rotating electric machine, and standby control that waits for the force running control and the negative torque applying control. And, the rotary electric machine control unit that selects and executes one control from at least two controls,
A rotation speed calculation unit that calculates the rotation speed of the crankshaft based on the crank angle detected by the crank angle sensor.
The rotation angle of the rotary electric machine is estimated when the rotation speed of the crank shaft calculated by the rotation speed calculation unit is higher than the estimated threshold value, and the rotation angle of the rotary electric machine is lower than the estimated threshold value. Rotation angle estimation unit that does not estimate
With
The rotary electric machine can apply the negative torque and the positive torque to the crankshaft.
The rotary electric machine control unit
The negative torque application control is selected and implemented on the condition that the stop crank angle acquired by the stop crank angle acquisition unit is smaller than the first threshold value in the forward rotation direction of the crankshaft.
When the stop crank angle acquired by the stop crank angle acquisition unit is larger than the second threshold value set larger than the first threshold value in the forward rotation direction of the crankshaft, the power running control is selected. Carry out,
A restart control device that performs the power running control 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 method according to any one of claims 1 to 7 , wherein the rotary electric 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 control device. The vehicle comprises a starter (16) for starting the engine.
The restart control device according to any one of claims 1 to 8 , further comprising a restart unit for rotating the crankshaft by the starter to restart the engine when the predetermined restart condition is satisfied. The rotary electric machine control unit executes 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 restart unit is configured when the power running control by the rotary electric machine control section in the following reached the second compression top dead center of the plurality of cylinders is carried out, in claim 9 for stopping the driving of the starter The restart control device described. The restart control device according to claim 9 , wherein the restart unit continues to drive the starter until the engine is completely detonated.

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