JP6350058B2 - Motor control device - Google Patents

Description

  The present invention relates to a vehicle motor control device having a function of starting an engine by a motor.

  An idling stop control device for the purpose of reducing fuel consumption of an engine stops the engine when a predetermined condition is satisfied. Further, the engine is restarted when a predetermined condition is satisfied while the engine is stopped. At this time, in order to improve drivability, it is necessary to restart the engine promptly according to the driver's request, but a certain torque is required to perform a smooth restart.

  When the driver makes a restart request due to brake release or the like when the engine speed drops, the motor control device instructs the motor to output torque and tries to start the engine smoothly. At this time, if the engine outputs torque immediately before the compression top dead center, a compression reaction force is generated in the engine. Therefore, the motor has the same torque as that at the start from the engine stop state or a magnitude larger than that. Torque is required.

  For this reason, if the torque required for the piston to overcome the compression top dead center exceeds the motor output torque, the semiconductor element in the motor will generate heat, consume more power than necessary, and take time to start the engine. Concerns have arisen.

  As a method for improving the reliability of engine starting, as disclosed in Patent Document 1, it is determined whether the starting torque of the motor generator for starting the engine is insufficient from the temperature of the motor generator and the temperature of the inverter. It is known that the engine is started using a starter when the generator starting torque is insufficient.

JP 2006-46279 A

  However, when the engine is restarted, if the engine outputs torque before the compression top dead center, the starting torque is required more than when starting from the engine stop state. For this reason, the engine start by the motor generator may fail only by looking at the temperature of the motor generator and the temperature of the inverter when determining whether or not the engine can be restarted as in Patent Document 1.

  Therefore, an object of the present invention is to provide a motor control device that can smoothly start an engine when the engine is started by the motor.

A motor control device according to the present invention includes a motor coupled to an engine crankshaft, an engine rotation speed detection unit that detects the rotation speed of the engine, and an idle stop unit during deceleration that stops the engine during deceleration of the vehicle the control device for a motor vehicle having the door, in a case where the to restart the engine when the rotational speed of the engine by the deceleration idling stop portion during deceleration of the vehicle is reduced, the engine When the engine speed is less than a predetermined second engine speed greater than the predetermined first engine speed and there is a cylinder in the compression stroke, it is determined that the engine cannot exceed the compression top dead center. and, when the engine is determined to be in a state that can not exceed the compression top dead center, less than the first rotational speed speed is the predetermined said engine It became by determining by driving the motor, characterized in that starting the engine.

  According to the present invention, when the engine is started by the motor, the engine can be started smoothly.

FIG. 1 is a block diagram of an apparatus including a motor controller for a vehicle having a function of starting an engine by a motor according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of a flowchart for determining whether motor torque output is possible or not in the vehicle motor control device having a function of starting the engine by the motor according to the first embodiment of the present invention. is there. FIG. 3 shows the engine speed when the motor torque output is executed according to the flowchart shown in FIG. 2 in the vehicle motor control device having the function of starting the engine by the motor according to the first embodiment of the present invention. It is a figure which shows an example of the example of a fluctuation | variation of Ne and a torque output. FIG. 4 is a diagram showing an example of a flowchart for determining whether or not motor torque output is possible in a vehicle motor control device having a function of starting an engine by a motor according to a second embodiment of the present invention. is there. FIG. 5 shows the engine speed when the motor torque output is executed according to the flowchart shown in FIG. 4 in the vehicle motor control device having the function of starting the engine by the motor according to the second embodiment of the present invention. It is a figure which shows an example of the example of a fluctuation | variation of Ne, crank angle (theta), and a torque output. FIG. 6 is a diagram showing an example of a flowchart for determining whether or not motor torque output is possible in a vehicle motor control device having a function of starting an engine by a motor according to a third embodiment of the present invention. is there.

  Hereinafter, a vehicle motor control device having a function of starting an engine by a motor according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

  FIG. 1 shows a schematic configuration of a vehicle, and particularly shows a device related to a vehicle motor control device 10 having a function of starting an engine by a motor according to a first embodiment of the present invention.

  The control device 10 includes a control unit 11, a deceleration idle stop unit 12, a crank angle detection unit 13, and an engine speed detection unit 14.

  As shown in FIG. 1, a deceleration idle stop unit 12, a crank angle detection unit 13, and an engine speed detection unit 14 are connected to the control unit 11. In addition, a battery 16, an engine 20, and a motor 22 are connected to the control unit 11. The motor 22 is connected to the crankshaft of the engine.

  The battery 16 supplies power directly to the control unit 11, the engine 20, and the motor 22, and via the control unit 11, the deceleration idle stop unit 12, the crank angle detection unit 13, the engine speed detection unit 14, and the like. Also supply power.

  Although the motor 22 is a DC motor, an AC motor may be used instead. However, when an AC motor is used, an inverter is provided so that AC power is supplied from the battery 16 to the AC motor via the inverter.

  The control unit 11 performs drive control of the engine 20 and the motor 22 based on signals from detection units (not shown) including the crank angle detection unit 13 and the engine speed detection unit 14. The driving force of the engine 20 is transmitted to the tire 30.

  The deceleration idle stop unit 12 requests the control unit 11 to perform deceleration idle stop when detecting that the vehicle speed is equal to or lower than the predetermined vehicle speed and the brake pedal is depressed during deceleration of the vehicle.

  When the control unit 11 receives a request for deceleration idle stop from the deceleration idle stop unit 12, in response to the request, the control unit 11 prohibits fuel injection to the engine 20 or prohibits ignition, or both fuel injection and ignition. Is prohibited.

  Further, the deceleration idle stop unit 12 requests the control unit 11 to restart the engine 20 when the driver requests the engine 20 to restart. For example, when the deceleration idle stop unit 12 detects that the driver has released the brake pedal, it determines that it is a restart request.

  The crank angle detector 13 detects the crank angle of the crankshaft with reference to the top dead center. The engine speed detection unit 14 detects the speed of the engine 20.

  The control unit 11 includes a storage unit (not shown). The storage unit includes a predetermined first rotation speed Ne *, a second rotation speed Ne2, and a third rotation speed Ne1 of the engine 20, a predetermined first crank angle θ1 and a second crank angle θ2. A predetermined descent speed Ned * of the engine speed is stored. As will be described later, the control unit 11 reads out and uses these stored values as necessary.

  FIG. 2 shows an example of a flowchart for determining whether torque output of the motor 22 is possible or not, which is executed in the control unit 11 according to the present embodiment.

  First, the controller 11 determines whether or not the deceleration idle stop is operating (step S21). The deceleration idle stop unit 12 requests the control unit 11 to perform the deceleration idle stop when detecting that the speed of the vehicle is equal to or lower than the predetermined value and that the driver depresses the brake pedal. . The control unit 11 determines whether or not the idle stop at the time of deceleration has been operated based on the presence or absence of this request.

  When the deceleration idle stop is operating, the control unit 11 executes at least one of the fuel injection prohibition and the ignition prohibition to the engine 20 to stop the combustion of the engine 20 in order to perform the deceleration idle stop. Yes.

  When it is determined in step S21 that the deceleration idle stop is operating (YES), the controller 11 determines whether or not an engine restart request has been made (step S22). For example, the deceleration idle stop unit 12 outputs a request for engine restart to the control unit 11 when detecting that the driver has performed a brake release or the like. Thereby, the control part 11 determines with the restart request | requirement of an engine having been made.

  In step S21, the control unit 11 determines that the idling stop at the time of deceleration is not operating (NO), or determines that the restart of the engine is not requested in step S22 (NO). In any case, since it is not necessary to determine whether or not the torque output of the motor 22 is possible, this process is terminated.

  In step S22, when the control unit 11 determines that the restart of the engine is requested (YES), the engine speed Ne detected by the engine speed detection unit 14 is set to a predetermined third value. It is determined whether or not the rotation speed Ne1 is between a predetermined second rotation speed Ne2 (step S23).

  The third rotation speed Ne1 and the second rotation speed Ne2 are both low engine speeds during deceleration, and the third rotation speed Ne1 is smaller than the second rotation speed Ne2.

  When the controller 11 determines in step S23 that the detected engine speed Ne is not between the third speed Ne1 and the second speed Ne2 (NO), the motor 22 (Step S26), the engine 20 is rotated to a predetermined rotational speed, and the engine 20 is restarted after fuel injection.

  As described above, when the detected engine speed Ne is not between the third speed Ne1 and the second speed Ne2, the piston of the engine 20 may exceed the compression top dead center by driving the motor. Therefore, the motor torque is output.

  On the other hand, when the controller 11 determines in step S23 that the detected engine speed Ne is greater than the third engine speed Ne1 and smaller than the second engine speed Ne2 (when YES), Subsequently, it is determined whether or not the detected engine rotational speed Ne is equal to or lower than a predetermined first rotational speed Ne * (step S25).

  When the detected engine speed Ne is between the third speed Ne1 and the second speed Ne2, it is difficult for the piston of the engine 20 to exceed the compression top dead center by driving the motor. However, when the engine speed Ne is equal to or lower than a predetermined first rotational speed Ne * lower than Ne1, the torque output of the motor 22 allows the piston of the engine 20 to exceed the compression top dead center. .

  Therefore, the first rotation speed Ne * is a rotation speed smaller than the third rotation speed Ne1, and is a value that can be determined that the engine 20 has stopped or can be predicted to stop. As the first rotation speed Ne *, for example, the rotation speed from 0 rpm to 100 rpm corresponds.

  When the controller 11 determines in step S25 that the detected engine speed Ne is greater than the first engine speed Ne * (NO), the engine engine speed Ne is the first engine speed Ne. The process of step S25 is repeated until it can be determined that the number is less than Ne *.

  When the controller 11 determines in step S25 that the detected engine speed Ne is equal to or lower than the first engine speed Ne * (YES), the controller 11 causes the motor 22 to output torque (step S26). ) The engine 20 is rotated, and the engine 20 is restarted after fuel injection.

  Thereby, the process for determining whether torque output of the motor 22 is possible ends.

  FIG. 3 shows an example of fluctuations in the engine speed Ne and torque output when the torque output of the motor 22 is executed according to the flowchart shown in FIG. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the size of each element.

  In FIG. 3, the deceleration idle stop is activated at time T0 when the engine speed has increased once after decreasing. That is, at the time T0, the vehicle speed is equal to or lower than the predetermined vehicle speed, and the driver is stepping on the brake pedal. If the process of step S21 of FIG. 2 is performed at this time, determination will be YES and a process will progress to step S22.

  As shown in FIG. 3, since the idling stop during deceleration operates from T0, the engine speed continues to decrease thereafter.

  When the engine speed continues to decrease, at time T1, for example, when brake release is performed, the control unit 11 receives a request for restarting the engine 20 from the idle stop unit 12 during deceleration. At this time, if the process of step S22 of FIG. 2 is executed, the determination is yes, and the process proceeds to step S23.

  At T1, the engine speed Ne is lower than the second speed Ne2 but higher than the third speed Ne1. For this reason, if the process of step S23 of FIG. 2 is executed at this time, the determination is YES, and the process proceeds to step S25.

  At time T1, it is difficult for the piston of the engine 20 to get over the compression top dead center with the torque output of the motor 22, so the engine speed Ne is further lowered. This corresponds to a case where the determination in step S25 in FIG. 2 is NO.

  At time T2, the engine speed Ne is lower than the third speed Ne1 and becomes the first speed Ne *. At this time, if the process of step S25 of FIG. 2 is executed, the determination is yes and the process proceeds to step S26.

  Therefore, the control unit 11 instructs the motor 22 to turn on the torque output at time T2. As a result, the engine 20 is restarted and the engine speed Ne increases after the time T2. Thus, according to this embodiment, the engine can be restarted without waiting for the engine 20 to stop.

  FIG. 4 shows an example of a flowchart for determining the propriety of motor torque output in the vehicle motor control device having a function of starting the engine by the motor according to the second embodiment of the present invention.

  The flowchart shown in FIG. 4 includes steps S21 to S23, step S25, and step S26 executed in the flowchart shown in FIG. For this reason, the description of these steps is omitted here.

  In the flowchart shown in FIG. 4, the same processing as the processing from step S <b> 21 to step S <b> 23 shown in the flowchart shown in FIG. 2 is executed, and in step 23, the controller 11 detects that the detected engine speed Ne is the third. When it is determined that the rotation speed is greater than the rotation speed Ne1 and smaller than the second rotation speed Ne2 (YES), the process proceeds to step S24.

  In step S24, the control unit 11 determines whether or not the crank angle θ detected by the crank angle detection unit 13 is between the predetermined first crank angle θ1 and the second crank angle θ2.

  The first crank angle θ1 is a crank angle before the compression top dead center, for example, an angle 30 ° to 40 ° before the angle indicating the compression top dead center. The second crank angle θ2 is an angle indicating a compression top dead center.

  When the detected crank angle θ is larger than the first crank angle θ1 and smaller than the second crank angle θ2, the piston of the engine 20 is in the compression stroke. Therefore, the piston is compressed by the torque of the motor 22 at this time. The top dead center cannot be exceeded.

  Therefore, when the detected crank angle θ is larger than the first crank angle θ1 and smaller than the second crank angle θ2 (in the case of YES), the control unit 11 continues in step S24. It is determined whether or not the detected engine rotational speed Ne is equal to or lower than a predetermined first rotational speed Ne * (step S25).

  When the controller 11 determines in step S25 that the detected engine speed Ne is equal to or lower than the first engine speed Ne * (YES), the controller 11 causes the motor 22 to output torque (step S26). ) The engine 20 is rotated, and the engine 20 is restarted after fuel injection.

  On the other hand, when the control unit 11 determines in step S24 that the detected crank angle θ is not between the first crank angle θ1 and the second crank angle θ2 (NO), the motor 11 The torque is output to 22 (step S26), the engine 20 is rotated to a predetermined rotational speed, and the engine 20 is restarted after fuel injection.

  Thereby, the process of the flowchart shown in FIG. 4 for determining whether or not the torque output of the motor 22 is possible ends.

  FIG. 5 shows an example of fluctuations in the engine speed Ne, the crank angle θ, and the torque output when the torque output of the motor 22 is executed according to the flowchart shown in FIG. In FIG. 5, the horizontal axis represents time, and the vertical axis represents the size of each element.

  The variation example of the engine speed Ne and the torque output in FIG. 5 is the same as the variation example of the engine speed Ne and the torque output in FIG. FIG. 5 shows an example of variation of the crank angle θ that is not shown in FIG. In the flowchart shown in FIG. 4, when the torque output of the motor 22 is executed, the fluctuation of the crank angle θ is considered as follows.

  In FIG. 5, at the time of T0 when the engine speed is increased after decreasing once, the deceleration idle stop is operated. That is, at the time T0, the vehicle speed is equal to or lower than the predetermined vehicle speed, and the driver is stepping on the brake pedal. At this time, in the flowchart shown in FIG. 4, when the process of step S21 is executed, the determination is YES, and the process proceeds to step S22.

  As shown in FIG. 5, since the idle stop at the time of deceleration operates from T0, the engine speed continues to decrease thereafter.

  When the engine speed continues to decrease, at time T1, for example, when brake release is performed, the control unit 11 receives a request for restarting the engine 20 from the idle stop unit 12 during deceleration. At this time, in the flowchart shown in FIG. 4, when the process of step S22 is executed, the determination is yes, and the process proceeds to step S23.

  Since the engine speed Ne is lower than the second speed Ne2 but higher than the third speed Ne1 at the time T1, it is determined that the process of step S23 of FIG. 4 is executed at the time T1. Becomes YES, and the process proceeds to step S24.

  On the other hand, the crank angle θ at time T1 is smaller than the second crank angle θ2 but larger than the first crank angle θ1.

  For this reason, at the time of T1, it is difficult for the piston of the engine 20 to overcome the compression top dead center with the torque output of the motor 22. If the process of step S24 of FIG. 4 is performed at this time, determination will be YES and a process will progress to step S25.

  At time T2, the crank angle θ is still between the second crank angle θ2 and the first crank angle θ1, but the engine speed Ne is lower than the third speed Ne1 and the first crank angle θ1. The rotation speed is Ne *.

  If the process of step S25 of FIG. 4 is performed at this time, determination will be YES and a process will progress to step S26.

  Accordingly, the control unit 11 instructs the motor 22 to turn on the torque output at time T2. As a result, the engine 20 is restarted and the engine speed Ne increases after the time T2. Thus, according to this embodiment, the engine can be restarted without waiting for the engine 20 to stop.

  FIG. 6 is a diagram illustrating an example of a flowchart for determining whether or not motor torque output is possible in a vehicle motor control device having a function of starting an engine by a motor according to the third embodiment.

  The flowchart shown in FIG. 6 includes steps S21 to S23, step S25, and step S26 executed in the flowchart shown in FIG. For this reason, the description of these steps is omitted here.

  In the flowchart shown in FIG. 6, the same processing as the processing from step S21 to step S23 shown in the flowchart shown in FIG. 2 is executed, and in step S23, the control unit 11 determines that the detected engine speed Ne is the third. If it is determined that the rotational speed is greater than Ne1 and smaller than the second rotational speed Ne2 (YES), the process proceeds to step S64.

  In step S64, the control unit 11 calculates the engine speed lowering speed Ned from the engine speed detected by the engine speed detecting unit 14 at predetermined time intervals, and the predetermined lowering speed is stored from the storage unit of the control unit 11. Ned * is read and it is determined whether Ned is smaller than Ned *.

  If the engine speed lowering speed Ned is smaller than the predetermined lowering speed Ned *, the lowering speed is insufficient, and the torque of the motor 22 at this time cannot cause the piston to exceed the compression top dead center.

  Therefore, when the controller 11 determines in step S64 that the engine speed decrease speed Ned is smaller than the predetermined speed decrease Ned * (when YES), the detected engine speed Ne is set to the default value. It is determined whether or not it is equal to or less than a predetermined first rotation speed Ne * (step S25).

  When the controller 11 determines in step S25 that the detected engine speed Ne is equal to or lower than the first engine speed Ne * (YES), the controller 11 causes the motor 22 to output torque (step S26). ) The engine 20 is rotated, and the engine 20 is restarted after fuel injection.

  On the other hand, when it is determined in step S64 that the engine speed decrease speed Ned is equal to or higher than the predetermined decrease speed Ned * (NO), the control unit 11 causes the motor 22 to output torque (step S26). ) The engine 20 is rotated to a predetermined speed, and the engine 20 is restarted after fuel injection.

  Thereby, the process of the flowchart shown in FIG. 6 for determining whether torque output of the motor 22 is possible ends.

  In the description of the above embodiment, the crank angle θ is focused on the crank angle θ in one cylinder. For this reason, for example, in the case of a three-cylinder engine, it is determined whether torque output of the motor 22 can be performed for each cylinder while the crankshaft rotates twice, and it is determined that torque output of the motor 22 can be performed for all three cylinders. Further, it is assumed that the control device 10 outputs a torque of the motor 22.

  The control device 10 for the motor 22 according to the first embodiment includes the motor 22 connected to the crankshaft of the engine 20, the engine speed detecting unit 14 for detecting the speed of the engine 20, and the engine during deceleration of the vehicle. And a deceleration idle stop section 12 that stops the engine 20, and the engine 20 is restarted when the rotational speed of the engine 20 is reduced by the deceleration idle stop section 12 during deceleration of the vehicle. When it is determined that the engine 20 is in a state where the compression top dead center cannot be exceeded, the motor 22 is driven by determining that the rotational speed of the engine 20 is equal to or lower than the predetermined first rotational speed. The engine 20 is driven.

  Due to this feature, when it is determined that the engine 20 cannot exceed the compression top dead center and the engine 20 cannot be started smoothly, the rotational speed of the engine 20 becomes equal to or lower than the first rotational speed. The engine 20 is restarted using the motor 22 on the condition of Thereby, it is possible to prevent the motor 22 from overheating when the engine 20 is restarted, waste of electric power from the battery 16, and an increase in the time required to restart the engine 20.

  Further, in the control device 10 of the motor 22, when the rotational speed of the engine 20 is less than a predetermined second rotational speed that is larger than the predetermined first rotational speed and there is a cylinder that is in the compression stroke, It may be determined that the compression top dead center cannot be exceeded.

  According to this, when the engine 20 is restarted, it can be determined from the engine speed that the engine 20 exceeds the compression top dead center and the engine cannot be started.

  While several embodiments of the present invention have been described as described above, it will be apparent to those skilled in the art that changes, modifications, or alterations may be made without departing from the scope of the present invention. Such alterations, modifications, and variations and equivalents are intended to be included within the scope of the claims.

DESCRIPTION OF SYMBOLS 10 Control apparatus 11 Control part 12 Deceleration idle stop part 13 Crank angle detection part 14 Engine rotation speed detection part 16 Battery 20 Engine 22 Motor 30 Tire

Claims (1)

A motor coupled to the crankshaft of the engine;
An engine speed detector for detecting the engine speed;
In a vehicle motor control device including a deceleration idle stop unit that stops an engine during deceleration of a vehicle,
The engine is restarted when the engine speed is reduced by the deceleration idle stop unit during deceleration of the vehicle, and the engine speed is greater than a predetermined first speed. Is determined to be less than the predetermined second rotational speed and the engine cannot exceed the compression top dead center when there is a cylinder in the compression stroke,
If the engine is determined to be in a state that can not exceed the compression top dead center, driving said motor by determining the rotational speed of the engine becomes a first rotational speed below the predetermined And a motor control device for starting the engine.

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