JP4103566B2 - Engine starter for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle engine starter having a motor generator for starting and generating power.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a vehicular engine starter equipped with a motor generator that performs at least engine start and power generation after engine start is known. Technology that connects the engine and motor generator through a clutch mechanism, connects an auxiliary machine (for example, an air conditioner compressor) to the motor generator, generates power while the engine is running, and drives the auxiliary machine when the engine is stopped (Also referred to as auxiliary machine drive technology when the engine is stopped) has also been proposed.
[0003]
The technology for performing engine start and power generation with one AC rotating electric machine can reduce the number of rotating electric machines as compared with a conventional vehicle electric system using a DC motor and an AC rotating electric machine dedicated to power generation, Since there is no concern about commutator wear, the reliability of an idle stop vehicle that requires frequent engine start can be improved.
[0004]
However, the AC rotating electric machine (generally synchronous machine) for both engine starting and power generation described above has a large physique weight compared to conventional AC rotating electric machines dedicated to power generation because of the large torque required for engine starting. There was a problem of increasing.
[0005]
On the other hand, Patent Document 1 below uses the inertial energy of the motor generator to start the engine by separating the clutch mechanism when starting the engine and rotating the motor generator to a certain number of rotations and then connecting the clutch mechanism. By doing so, it has been proposed to reduce the required torque of the motor generator and reduce its size and weight.
[0006]
[Patent Document 1]
JP 2002-89417 A
[Problems to be solved by the invention]
However, in the engine start method described above (hereinafter also referred to as inertia start method), the time required for starting the engine is extended by the time required to start up the rotational speed of the motor generator. In addition to the disadvantage that the clutch mechanism cannot be engaged, the clutch mechanism cannot be engaged with the pair of rotating shafts in their stationary state.
[0008]
The present invention has been made in view of the above problems, and provides a vehicle engine starter capable of realizing a reduction in the size and weight of a motor generator while suppressing an increase in time required for engine start and consumption of a clutch mechanism. That is the purpose.
[0009]
[Means for Solving the Problems]
The vehicle engine starter of the present invention is suitably applied to a so-called idle stop vehicle, has a rotation angle sensor for detecting the rotation angle of the rotor, and can transmit bidirectional power to the engine via a clutch mechanism. an electric generator comprising a synchronous machine which is connected a DC power supply and an electrical load to the motor generator when disposed performs bidirectional orthogonal power conversion between both the electric generator during the electric operation of the motor generator An inverter circuit that applies a pulse voltage or a step voltage that changes stepwise to the inverter circuit, and controls the inverter circuit based on the rotation angle when an engine start command is input, thereby generating torque generated by the motor generator through the clutch mechanism. A vehicle engine comprising: a controller for performing an engine start operation for transmitting to the engine to start the engine In emissions starting device,
Connection of the clutch for starting the engine is performed when the controller starts rotating the rotor in a state where the clutch mechanism is disengaged in advance and the rotor is rotated near the maximum generated torque position. It is characterized by being implemented before the As a result, it is possible to reduce the size and weight of the motor generator while preventing the extension of the time required for engine start in the case of engine start using a motor generator that performs engine start and power generation, and suppressing consumption of the clutch mechanism. Can do.
[0010]
That is, when a pulse voltage or a step voltage that changes stepwise is applied to the motor generator, the magnitude of the electric torque may change periodically depending on the rotation angle of the rotor, more precisely, the position of the rotor magnetic pole. Are known. For example, in a three-phase synchronous machine, a generated torque maximum position point is generated every electrical angle π / 3.
[0011]
In the device configuration in which the motor generator is connected to the engine through the clutch mechanism, the inventor can freely rotate the motor generator by disconnecting the clutch mechanism when the engine is stopped, and the periodicity of the motor generator. The torque generator is focused on the combination with the torque fluctuation phenomenon, and the motor generator is rotated in advance to the maximum generated torque position in the periodic fluctuation before starting the engine by using the motor generator free rotation function. As a result, the torque of the motor generator, that is, the engine starting torque can be maximized at the time of subsequent engine starting, so that the motor generator can be reduced in size, and further, since the inertia starting is not performed, the wear of the clutch mechanism is also reduced. can do.
[0012]
In a preferred aspect, the motor generator is connected to a predetermined auxiliary machine without passing through the clutch mechanism, and the controller is configured to drive the auxiliary machine when the engine start command is input. The engine starting operation is performed without performing the rotor preliminary rotating operation.
[0013]
As a result, for example, in a motor generator apparatus having an engine start / power generation / independent auxiliary drive function for an idle stop vehicle that drives an auxiliary machine (usually an air conditioner compressor) when the engine is stopped, the motor generator drives the auxiliary machine. In this case, it is possible to start the engine immediately using its own inertia energy without performing the preliminary rotation operation of the rotor, and it is necessary to start the engine by performing the preliminary rotation operation of the rotor after inputting the engine start command. The problem that the time is long can be solved, and as a result, even when the motor generator is stopped and when the auxiliary machine is driven, a quick engine start can be realized by a small motor generator.
[0017]
In a preferred aspect, the controller rotates the rotor of the motor generator within a range from a maximum torque position of −10 degrees to a maximum torque position of +10 degrees by the preliminary rotation. Thereby, the engine starting torque which a motor generator generate | occur | produces can be increased favorably.
[0018]
In a preferred embodiment, the motor generator is a three-phase synchronous machine, and the inverter circuit is energized and controlled at 120 degrees at least at the initial stage of the engine start. When the engine speed exceeds a predetermined value, the inverter circuit is rotated 180 degrees. Energize control.
[0019]
The synchronous machine has the maximum starting torque when 120-degree energization control is performed, but the torque at high speed is greater when the control is controlled by 180-degree energization or sinusoidal energization. Therefore, according to this aspect, the torque at the time of starting the engine, that is, the starting torque is improved, and the increase in the engine speed after the engine speed is increased by the engine start is quickly increased (improves the blow-up). The time required for starting the engine can be further reduced.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the vehicle engine starter of the present invention will be described below with reference to the block diagram shown in FIG.
[0021]
(Description of overall configuration)
In FIG. 1, 1 is an engine, 2 is a motor generator, 3 is a rotation angle sensor, 4 is a battery, 5 is an electric load, 6 is an inverter circuit, 7 is a clutch mechanism, 8 is a controller, 9 is a belt, and 10 is an air conditioner. Compressor (auxiliary machine).
[0022]
The engine 1 is connected to the engine pulley through a clutch mechanism 7 built in the engine pulley, and the engine pulley is constituted by a pulley and a belt 9 fixed to the rotating shafts of the motor generator 2 and the air conditioner compressor (auxiliary machine) 10, respectively. It is connected.
[0023]
The motor generator 2 is composed of a three-phase synchronous machine. The motor generator 2 exchanges power with the battery 4 through the inverter circuit 6 and supplies power to the motor generator 2.
[0024]
The inverter circuit 6 connects the motor generator 2 and the battery 4 so as to be capable of bidirectional orthogonal power conversion, converts the DC power fed from the battery 4 into three-phase AC power in the electric operation of the motor generator 2, and is electrically driven. Power is supplied to the generator 2, and three-phase AC power generated by the motor generator 2 in the power generation operation of the motor generator 2 is three-phase full-wave rectified and supplied to the battery 4 and the electric load 5. In this embodiment, the inverter circuit 6 is a three-phase inverter circuit, which has three upper arms and three lower arms, and each arm is composed of a switching element and a diode connected in reverse parallel thereto. When the MOS transistor is used, the th controller 8 whose switching element can also serve as a diode constitutes each arm of the inverter circuit 6 based on the rotation angle signal output from the rotation angle sensor 3 during the electric operation of the motor generator 2. The switching element to be controlled is intermittently controlled and the disengagement of the electromagnetic clutch constituting the clutch mechanism 7 is controlled.
[0025]
The above-described vehicle engine starting device has a well-known configuration, and a detailed description thereof is omitted.
[0026]
FIG. 2 shows an electric circuit system of the vehicle engine starter shown in FIG. In FIG. 2, reference numeral 2 a denotes a rotor of the motor generator 2, and 2 b denotes three phase coils constituting a stator coil of the motor generator 2.
[0027]
The torque fluctuation phenomenon of the motor generator 2 is shown in FIG. When performing sine wave energization control (see FIG. 4) for energizing a sine wave to the three-phase stator coil of the motor generator 2, the period fluctuation of the electric torque hardly occurs, but 120 degree energization control (see FIG. 6). ) Or 180-degree energization control (see FIG. 5), torque ripple occurs at an electrical angle of 60 degrees. The cause of this torque ripple is that in these 120 degree energization control and 180 degree energization control, the applied voltage waveform is considerably distorted from the sine wave, and therefore the torque varies in response to this distortion.
[0028]
(Description of synchronous motor torque pulsation)
Next, the difference in starting torque at the time of starting the motor due to the difference in each energization control method will be described below with reference to FIGS. 7 to 12 show the vector voltages of the respective phases in the U, V, and W coordinate systems with the U-phase vector voltage in the vertical direction on the paper, and their combined vector voltages. Assume that a vector voltage in the same direction as the arrow symbols on the U, V, and W coordinate axes has a positive voltage value, and a reverse vector voltage has a negative voltage value. The length of each vector voltage indicates the magnitude of the voltage, the number described in the vicinity of each vector voltage indicates the magnitude of the vector voltage, and the number described in bold indicates the magnitude of the three-phase combined vector voltage.
[0029]
7 to 9 show the vector voltages of the respective phases and their combined vector voltages when the rotor is located at the electrical angles of 0 degrees, 30 degrees, 60 degrees, and 90 degrees in order from the left, respectively. Reference numeral 12 denotes a combined vector voltage (shown by a solid line) when the rotor is at an electrical angle of 0 degrees, 15 degrees, and 30 degrees in order from the left, and a projected vector voltage obtained by projecting the combined vector voltage on an axis of a predetermined phase ( (Shown with a broken line).
[0030]
The axis of the predetermined phase is an axis having an energization phase that maximizes the torque generated by the electric motor, and is indicated by a one-dot chain line in the drawing. Actually, this energization phase changes somewhat depending on conditions such as current and rotor specifications, but here, it is assumed that it is a phase advanced by an electrical angle of 90 degrees from the main magnetic flux of the rotor.
[0031]
FIG. 7 shows the phase vector voltage and the combined vector voltage in the case of performing sine wave energization control. In sine wave energization control, the combined vector voltage is always the same magnitude and continuously follows the rotor position and rotates.
[0032]
FIG. 8 shows the phase vector voltage and the combined vector voltage when 180-degree energization control is performed. In the 180-degree energization control, the combined vector voltage having the same magnitude as that of the sine wave energization control rotates (switches) intermittently following the rotor position at an electrical angle interval of 60 degrees.
[0033]
FIG. 9 shows changes in the phase vector voltage and the combined vector voltage when the 120-degree energization control is performed. In 120-degree energization control, the magnitude of the combined vector voltage is larger than in sine-wave energization control and 180-degree energization control, but the phase intermittently follows the rotor position at 60-degree intervals as in 180-degree energization control. Rotate (switch).
[0034]
FIG. 10 shows the phase relationship between the combined vector voltage and the rotor in the sinusoidal conduction control. Since the rotor always rotates synchronously with the combined vector voltage, a constant torque is always generated regardless of the phase (rotation position) of the rotor.
[0035]
FIG. 11 shows the phase relationship between the combined vector voltage and the rotor in the 180-degree energization control. As described above, in the 180-degree energization control, the phase of the combined vector voltage is switched stepwise. For example, when the electrical angle is 0 degrees or 15 degrees, the combined vector voltage phase and the rotor phase are shifted, and the combined vector voltage is The vector component projected on the alternate long and short dash line (the voltage component that generates torque) becomes smaller, and eventually the torque fluctuates at a period of 60 electrical angles according to the rotation of the rotor.
[0036]
FIG. 12 shows the phase relationship between the combined vector voltage and the rotor in 120-degree energization control. As described above, the phase of the combined vector voltage is switched stepwise even in the 120-degree energization control. For example, at an electrical angle of 15 degrees or 30 degrees, the combined vector voltage phase and the rotor phase shift, and the combined vector voltage The vector component projected on the alternate long and short dash line (the voltage component that generates torque) becomes smaller, and eventually the torque fluctuates at a period of 60 electrical angles according to the rotation of the rotor.
[0037]
As shown in FIG. 3, the maximum torque in the 120-degree energization control is about 15% larger than the maximum torque in the 180-degree energization control. Therefore, it is preferable to adopt 120-degree energization control at the start of engine start. However, in spite of this, the 180-degree energization control is usually adopted because the effective average voltage of the 180-degree energization control is higher than that of the 120-degree energization control.
[0038]
(Explanation of engine start control)
Next, a control example of the vehicle engine starter according to this embodiment described above will be described below with reference to a flowchart shown in FIG.
[0039]
First, it is determined whether or not the motor generator 2 is rotating based on an input signal from the rotation angle sensor 3 (S100). If the motor generator 2 is rotating, the clutch mechanism 7 is instructed to be engaged (S102). Thus, the motor generator 2 is controlled by current control to start the engine 1 (S104). When the engine speed or the motor generator 2 reaches a predetermined value, it is determined that the engine has been started (S105). End the start control. The fact that the motor generator 2 is rotating usually means that the motor generator 2 is driving the compressor (auxiliary device) 10 for the air conditioner. In this case, since the motor generator 2 starts the engine using its own inertia energy (kinetic energy), the engine can be started without any problem even if the generated torque is somewhat small.
[0040]
Next, when it is determined in step S100 that the engine 1 is stopped, the rotor rotational position is pre-stored based on the input signal from the rotational angle sensor 3 in the vicinity of the maximum torque generation position (the electrical angle +/- (Within a range of 10 degrees) (S106), if not, the current rotor rotational position is read (S108), and the maximum torque generation position closest (or predetermined) to the current rotor rotational position is determined. A routine for calculating a phase difference between the motor generator 2 (S110), energizing the stator coil of the motor generator 2 for a predetermined time to rotate the rotor in a direction to reduce the phase difference (S112), and returning to step S106. Repeatedly, the rotor rotation position is set near the maximum torque generation position.
[0041]
In step S106, when the rotor rotational position is close to the maximum torque generation position stored in advance, the process proceeds to step S114 to command the clutch mechanism 7 to engage (S114), and it is determined whether the rotor rotational speed has exceeded a predetermined value. If not (S116), the motor generator 2 is activated by 120-degree energization control (S118), and the process returns to step S116. In step S116, if the rotor rotational speed exceeds a predetermined value, the motor generator 2 is driven by switching to 180-degree energization control (S120), and the process proceeds to step S105.
[0042]
(Modification)
A modification of the above embodiment is shown in FIG.
[0043]
In this modification, the clutch mechanism 7 is built in the pulley of the motor generator 2. Even in this case, the same effect as described above can be obtained.
[0044]
(Modification)
A modified embodiment of the above embodiment is shown in FIG.
[0045]
In this modification, the clutch mechanism 7 is built in the pulley of the motor generator 2 (or disposed between the motor generator pulley and the rotating shaft of the motor generator 2), and the auxiliary machine 10 is omitted. Yes. Even in this case, the same effect as described above can be obtained. In this modification, an auxiliary machine can be directly connected to the rotating shaft of the motor generator 2.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a preferred embodiment of a vehicle engine starter according to the present invention.
FIG. 2 is a circuit diagram showing a main part of an electric circuit of the vehicle engine starter shown in FIG. 1;
FIG. 3 is a timing chart showing a torque fluctuation phenomenon of the motor generator.
FIG. 4 is a timing chart showing sine wave energization control for energizing a sine wave to a three-phase stator coil of a motor generator.
FIG. 5 is a timing chart showing changes in each phase voltage when the motor generator is subjected to 120-degree conduction control.
FIG. 6 is a timing chart showing changes in each phase voltage when the motor generator is subjected to 180-degree energization control.
FIG. 7 is a vector diagram showing vector voltages of respective phases and their combined vector voltages in sine wave energization control.
FIG. 8 is a vector diagram showing vector voltages of respective phases and their combined vector voltages in 180 degree energization control.
FIG. 9 is a vector diagram showing vector voltages of respective phases and their combined vector voltages in 120-degree energization control.
FIG. 10 is a vector diagram showing a phase relationship between a combined vector voltage and a rotor in sine wave energization control.
FIG. 11 is a vector diagram showing a phase relationship between a combined vector voltage and a rotor in 180-degree energization control.
FIG. 12 is a vector diagram showing a phase relationship between a combined vector voltage and a rotor in 120-degree energization control.
FIG. 13 is a flowchart showing an engine start control operation in this embodiment.
FIG. 14 is a block diagram showing a modification of the vehicle engine starter according to the present invention.
FIG. 15 is a block diagram showing a modification of the vehicle engine starter according to the present invention.
[Explanation of sign]
DESCRIPTION OF SYMBOLS 1 Engine 2 Motor generator 3 Rotation angle sensor 4 Battery 5 Electric load 6 Inverter circuit 7 Clutch mechanism 8 Controller 9 Belt 10 Air conditioner compressor (auxiliary machine)

Claims (4)

A motor generator comprising a synchronous machine having a rotation angle sensor for detecting the rotation angle of the rotor and coupled to the engine via a clutch mechanism so that bidirectional power transmission is possible;
Step voltage the varying pulse voltage or stepwise to the motor generator when the electric operation of the arrangement has been performed bidirectional orthogonal power conversion both the motor generator between a DC power source and an electric load and the electric generator An inverter circuit to be applied;
A controller for performing an engine start operation for starting the engine by transmitting the torque generated by the motor generator to the engine through the clutch mechanism by controlling the inverter circuit based on the rotation angle when an engine start command is input;
In a vehicle engine starter comprising:
The controller is
Before starting the engine, a rotor pre-rotation operation in which the rotor is rotated in the vicinity of the maximum generated torque position with the clutch mechanism disengaged in advance is performed before the clutch is connected for starting the engine. An engine starter for a vehicle characterized by being implemented. The vehicle engine starter according to claim 1,
The motor generator is connected to a predetermined auxiliary machine without the clutch mechanism,
The controller is
A vehicle engine starter that performs the engine start operation without performing the rotor pre-rotation operation when the motor generator drives the auxiliary machine when the engine start command is input . The vehicle engine starter according to claim 1,
The controller is
A vehicle engine starter that rotates the rotor of the motor generator within a range of a maximum generated torque position of -10 degrees to a maximum generated torque position of +10 degrees by the preliminary rotation. The vehicle engine starter according to any one of claims 1 to 3 ,
The motor generator consists of a three-phase synchronous machine,
The controller is
A vehicle engine starter that performs energization control of the inverter circuit at 120 degrees at least at the initial stage of the engine start, and controls the inverter circuit by energization of 180 degrees or sine wave if the engine speed exceeds a predetermined value.

Images