JPH05302526A - Device for restraining variation in engine speed - Google Patents

Abstract

PURPOSE:To enhance the restraint on variation in rotational speed of an engine by actively controlling a torque generated by a generator motor in accordance with a variation in rotational speed of an engine. CONSTITUTION:An ECU 13 receives an output pulse signal from a rotary encoder 12 coupled to the crankshaft 12 of an engine 1, and detects a crankangle and a rotational speed of an engine 1. The ECU 13 feeds back thus detected rotational speed of the engine so as to computes a torque to be generated by a generator motor 5, and delivers a result of the computation to a current controller and a control circuit 17 so as to control a current fed to field windings of the generator motor 5 and the switching of operation modes of the generator motor 5. Accordingly, it is possible to actively control the torque generated by the generator motor 5 in consideration of a rotational speed of the engine 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine rotational speed fluctuation suppressing device for suppressing fluctuations in engine rotational speed by means of torque generated by a generator motor.

[0002]

2. Description of the Related Art A conventional engine rotational speed fluctuation suppressing device is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-135936.
When the engine rotation speed (angular speed) is higher than the average rotation speed, reverse torque is applied to the engine by driving the generator motor with the output torque of the engine and operating the generator motor as a generator, During the period when the speed is lower than the average rotation speed, the generator motor is operated as an electric motor to apply a positive torque to the engine. In this case, the switching timing of the operation mode of the generator motor is determined by the crank angle of the engine, as shown in FIG. 7 of the above publication.

[0003]

By the way, as shown in FIG. 6 of the above publication, the engine rotation speed (angular speed) changes every moment, so that the most effective suppression of the fluctuation of the engine rotation speed is as follows. Ideally, the torque generated by the generator-motor is changed every moment according to the fluctuation of the engine rotation speed.

However, in the above publication, the generated torque of the generator motor is not controlled at all by simply switching the operation mode of the generator motor according to the crank angle of the engine. As a result, the generated torque of the generator motor is not always suitable, and the effect of suppressing fluctuations in rotation speed is also reduced. Moreover, when the engine speed temporarily becomes unstable, such as when a part of the cylinders of the engine misfires or when an external load such as power steering is input, it is necessary to suppress the fluctuation of the engine speed. The torque generated by the generator motor becomes more and more unsuitable for the originally required torque, and on the contrary the torque generated by the generator motor acts in the direction of increasing the rotation speed fluctuation, and the drop in the engine rotation speed becomes even greater. The engine may stall in the worst case.

The present invention has been made in consideration of such circumstances, and an object thereof is to be able to actively control the torque generated by a generator-motor in accordance with changes in the engine rotation speed, An object of the present invention is to provide an engine rotational speed fluctuation suppressing device that can effectively suppress fluctuations in the engine rotational speed even when some cylinders of the engine are misfired or an external load such as power steering is input.

[0006]

In order to achieve the above object, the engine rotational speed fluctuation suppressing device of the present invention is such that the fluctuation of the engine rotational speed is suppressed by the torque generated by the generator motor. Rotation speed detection means for detecting the rotation speed, generated torque calculation means for calculating the torque to be generated by the generator motor by feeding back the engine rotation speed detected by the rotation speed detection means, and calculation by the generated torque calculation means And a control means for controlling the operation of the generator motor based on the result.

[0007]

According to the above construction, the engine speed is detected by the rotation speed detecting means, and the detected value is fed back to calculate the torque to be generated by the generator motor by the generated torque calculating means. Since the control means actively controls the operation of the generator motor based on the result of this calculation, the generated torque of the generator motor is adapted to the fluctuation of the engine rotation speed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, the overall mechanical configuration will be described with reference to FIGS. 1 and 2. The engine 1 is, for example, a 4-cycle gasoline engine, and a torque converter 4 of a transmission 3 is connected to one end of a crankshaft 2 thereof. A generator motor 5 is arranged at a position between the torque converter 4 and the engine 1 (a position where the flywheel is originally mounted and installed), and a rotor core 6 of the generator motor 5 is arranged.
Are fixed to the crankshaft 2 via bolts 7. The rotor core 6 is excited by a field winding 8 (rotor coil) arranged inside the rotor core 6.

A housing 9 which covers the outer periphery of the generator motor 5 is fixed to the side surface of the engine 1, and a stator core 10 is fixed inside the housing 9 so as to surround the outer periphery of the rotor core 6. This stator core 10
Slot 10a of the three-phase stator coil 11a,
11b and 11c are attached.

On the other hand, a rotor (not shown) of the rotary encoder 12 is connected to the other end of the crankshaft 2 of the engine 1. This rotary encoder 12
Generates a pulse signal each time the rotation angle (crank angle) of the crankshaft 2 reaches a certain angle (for example, 10 ° CA or less), and the pulse signal is generated by an electronic control unit (hereinafter referred to as “ECU”). Thirteen
Detects the crank angle by counting, and
The rotation speed of the engine 1 is detected by measuring the time interval of the pulse signal. Therefore, in this embodiment, the rotary encoder 12 and the ECU 1
The rotation speed detecting means for detecting the rotation speed of the engine 1 is constituted by the elements 3 and 3.

Further, the ECU 13 is connected with a vehicle speed sensor 14 for generating a vehicle speed signal according to the vehicle speed of the vehicle and an idle switch 15 for generating a throttle fully closed signal when an accelerator (not shown) is turned off. ing. At the time of idling, the ECU 13 determines an idling state from the vehicle speed signal and the throttle fully closed signal, and controls an idling speed control actuator (hereinafter referred to as “ISC actuator”) 16 to operate a throttle valve (not shown). The opening is adjusted to stabilize the idle speed.

The ECU 13 also controls the operation of the generator motor 5 via the control circuit 17 and the drive circuit 18. Less than,
The electric circuit of this control system will be described with reference to FIG.

The drive circuit 18 comprises an inverter / converter 19 and a current controller 20 for controlling the current value If flowing in the field winding 8. The inverter / converter 19 includes six transistors Tx and Ty.
, Tz, Tu, Tv, Tw are connected in a three-phase bridge, and each of the transistors Tx, Ty, Tz, Tu, Tv,
The diodes Dx, Dy, Dz, Du and D are respectively connected to Tw.
It is constructed by connecting v and Dw in anti-parallel. The connection terminals U, V, W of each phase of the inverter / converter 19 are
It is connected to the stator coils 11a, 11b and 11c of each phase.

When the generator motor 5 is operated as an electric motor, it is supplied from the battery 21 by controlling ON / OFF of each of the transistors Tx, Ty, Tz, Tu, Tv, Tw by the control circuit 17. DC power is converted into three-phase AC power, and this AC power excites the stator coils 11a, 11b, and 11c of each phase to rotate the rotor core 6. In this case, each diode Dx, Dy, Dz, Du, Dv, Dw acts as a flywheel diode.

On the other hand, when the generator motor 5 is operated as a generator, the control circuit 17 turns off all the transistors Tx, Ty, Tz, Tu, Tv, and Tw so that the stator of each phase is turned on. Coil 11a,
AC power induced by 11b and 11c is applied to each diode D
The battery 21 is charged by being rectified through x, Dy, Dz, Du, Dv, Dw. In this case, each diode D
x, Dy, Dz, Du, Dv, Dw act as a rectifying diode.

On the other hand, the current controller 20 controls the current value If flowing in the field winding 8 of the generator motor 5 to generate the amount of power generated by the generator (negative generated torque).
Controls the rotation speed (positive generated torque) of the electric motor.

In this case, the control circuit 17 and the current controller 20 are controlled by the ECU 13. This ECU
The reference numeral 13 functions as a generated torque calculation means for feeding back the rotational speed of the engine 1 to calculate the torque to be generated by the generator motor 5 by executing each routine of FIGS. 4 and 5 described later. The control circuit 17 and the current controller 20 controlled by the ECU 13 are
It functions as a control unit that controls the operation of the generator motor 5 based on the calculation result of the CU 13. Hereinafter, this control content will be specifically described with reference to the flowcharts of FIGS. 4 and 5.

The engine operating state determination routine shown in FIG.
Based on the output pulse signal of the rotary encoder 12,
This is executed by interrupt processing each time the crank angle of the engine 1 advances by 30 ° CA, for example.

In this engine operating state determination routine,
First, in step S1, it is determined whether or not a key switch (not shown) is rotationally operated to a start position, that is, whether or not the engine 1 is being started, and "YES".
If so, the process proceeds to step S2, and it is determined whether the rotation speed Ne of the engine 1 is lower than a predetermined value n. The predetermined value n is the rotation speed when the engine 1 is in the complete explosion state, and if the rotation speed of the engine 1 is the predetermined value n.
If it has not reached, the determination is “YES” in step S2, the process proceeds to step S3, the current value If flowing in the field winding 8 is set to, for example, 6 A, and the generator motor 1 is used as a motor (starter). To operate. In this case, the execution determination flag XSIDL is set to "0" (step S5), and this routine ends. The execution determination flag XSIDL is a flag for determining whether or not to execute the rotation speed fluctuation suppression control (the processing of steps S12 to S17 in FIG. 5), and when "0", the control is not performed.
Only when it is "1" will the control be performed.

If the rotational speed Ne of the engine 1 exceeds a predetermined value n during the starting operation of the engine 1 (when step S1 is "YES"), it is determined to be "NO" in step S2. Then, the process proceeds to step S4 and the current value If flowing in the field winding 8 is set to, for example, -2 A, and the generator motor 1 is operated as a generator. Also in this case,
Similar to the above, the execution determination flag XSIDL is set to "0" (step S5), and this routine is ended.

On the other hand, if "NO" is determined in step S1, that is, if the starting operation of the engine 1 is not being performed, the rotation speed (average value) of the engine 1 is stable in idle rotation in steps S6 to S9. Whether or not it is in the state is determined as follows. First, step 6
Then, it is determined whether the rotation speed Ne of the engine 1 is lower than a predetermined value n. If the rotation speed of the engine 1 is lower than the predetermined value n, it is determined as "YES" in step S6, the process proceeds to step S7, and the idle switch 15
Is on and whether or not the throttle fully closed signal is output, that is, whether or not the accelerator (not shown) is off is determined. If step 7 also determines "YES", the process proceeds to step S8 and the vehicle speed sensor 1
It is determined whether the output signal level of 4 is 0 V or less, that is, whether the automobile is stopped.

If "YES" is also determined in this step S8, the process proceeds to step S9, and it is determined whether or not the feedback control of the ISC actuator 16 (the feedback control of the idle rotation speed) is being performed. If "YES" is determined in step S9, the process proceeds to step S10 and the execution determination flag XSI
DL is set to "1" and this routine ends.

On the other hand, if any one of the steps S6, S7, S8 and S9 is "NO", it means that the rotation speed of the engine 1 has not dropped to a stable idle rotation state. In step S4, the current value If flowing in the field winding 8 is set to, for example, -2A, the generator motor 1 is operated as a generator, and the execution determination flag XSIDL is set to "0" ( Step S
5) Then, this routine is finished.

When the determination in step S6 is "NO", it means that the rotation speed of the engine 1 is equal to or higher than the predetermined value n, and when the determination in step S7 is "NO", This is a case where the idle switch 15 is off and the throttle fully closed signal is not output (the accelerator is depressed). When the determination in step S8 is "NO", it means that the output signal level of the vehicle speed sensor 14 is higher than 0V (the vehicle is not stopped). Furthermore, when the determination in step S9 is "NO", it means that the ISC actuator 16 is not being feedback-controlled.

On the other hand, the rotational speed fluctuation suppression control routine of FIG. 5 is executed by interrupt processing based on the output pulse signal of the rotary encoder 12 every time the crank angle of the engine 1 advances by, for example, 10 ° CA. In this routine, first, in step S11, the execution determination flag XSID
It is determined whether or not L is "1", and if "NO", the following rotational speed fluctuation suppression control (steps S12 to S1) is performed.
The process returns to the main program without executing (Process 7).

If the execution determination flag XSIDL is "1"
If so, the determination in step S11 becomes "YES", the process proceeds to step S12, and the torque TD (i) to be generated by the generator motor 5 is calculated by the following equation (1).

[0027]

[Equation 1] Here, TD (i) is the torque required at the present time i, and TD (i-1) is required at the time point (i-1) one step before the present time i (10 ° CA). It is torque. And Ne (i) is the engine 1 of the current time i.
Is the rotation speed [unit is rpm], and Ne (i-1) is
It is the rotation speed [unit is rpm] of the engine 1 at a time point (i-1) one step before the current time point i. K is a constant determined by the following equation (2).

[0028]

[Equation 2] Here, Δθ is a control cycle (10 ° CA in this embodiment), and J is the moment of inertia of the rotating system of the generator motor 5.

Formula (1) for the above-mentioned torque TD (i)
Is derived as follows by the idle vibration suppression control examination simulation shown in FIG.

A. Rotational dynamics

[Equation 3] Here, ω is the crank angular velocity [rad / sec], Te is the torque generated by the engine 1, TD is the torque generated by the generator motor 5, and Tf is the friction torque lost due to sliding friction.

In the present embodiment, the operation of the generator motor 5 is controlled by the crank angle of the engine 1. Therefore, when the time differential of the equation (4) is converted into the crank angle differential,

[Equation 4]

B. Damping control method ω = (2π / 60) Ne is substituted into the equation (7) and rearranged using α of the equation (3),

[Equation 5] In this case, in order to eliminate the fluctuation of the rotation speed of the engine 1, a control method for determining TD (i) is such that Te (i) + TD (i) −Tf (i) = 0 (11). Will be needed.

From equation (11), TD (i) =-Te (i) + Tf (i) (12), but it is difficult to know Te (i) and Tf (i) at the present time i. Because there is

[Equation 6] Assuming that
The method of estimating -Te (i-1) + Tf (i-1) of the previous) from a known signal is adopted.

From equation (10),

[Equation 7] Therefore, -Te (i-1) + Tf (i-1) can be estimated from the known signal. Therefore, substituting equation (16) into equation (14),

[Equation 8] By substituting the expression (2) into the expression (17), the arithmetic expression (1) for obtaining the torque TD (i) to be generated by the generator motor 5 is derived.

Using this equation (1), the torque TD (i) is calculated in step S12 of the rotational speed fluctuation suppression control routine.
After calculating, the process proceeds to step S13 and the torque TD is calculated.
It is determined whether the calculated value of (i) is positive (+), negative (-), or zero (0). Here, if the torque T
If the calculated value of D (i) is zero (0), the generator motor 5 does not need to perform power generation and electric operation, so the current value If flowing in the field winding 8 is set to 0A (step S1).
5).

On the other hand, when the calculated value of the torque TD (i) is positive (+), it is necessary to operate the generator motor 5 as an electric motor. Therefore, the process proceeds to step S14, and FIG.
A positive current value If is obtained from the motor torque characteristic of Figure 7
The motor torque characteristics of the current value If = 0, 2, 4, 6
[A] shows the relationship between the rotation speed Ne of the engine 1 and the generated torque TD of the generator motor 5. The method for obtaining the current value If from the electric motor torque characteristic of FIG. 7 is to calculate the current value If = 0, 2, 4, 6 [A] from the torque curve, and the current speed i Ne (i) and the torque TD.
Select one that satisfies the condition (i). The electric motor torque characteristics shown in FIG. 7 are stored in the ECU 1 as a data table or a function.
3 ROM (not shown).

Further, when the calculated value of the torque TD (i) is negative (-), it is necessary to operate the generator motor 5 as a generator, so the routine proceeds to step S16, and FIG.
From the generator torque characteristics of the above, the negative current value I
Find f. The generator torque characteristic of FIG. 8 is the current value If =
Engine 1 for 0, -1, -2, -4, -6 [A]
It is a representation of the rotational speed Ne and the input torque TD of the generator motor ^5, the relationship between the. In this case, the generated torque TD of the generator motor 5 becomes a negative value, TD = - ^TD, become.
The motor torque characteristic of FIG. 8 is also stored in the ROM (not shown) of the ECU 13 as a data table or a function.

As described above, steps S14 to S1
The data of the current value If obtained in 6 is output from the ECU 13 to the current controller 20 (step S17).
Thereby, the current controller 20 controls the current value If flowing in the field winding 8 of the generator motor 5,
It controls the amount of power generation (negative generated torque) as a generator and the rotation speed (positive generated torque) as an electric motor.

At this time, when the generator motor 5 is operated as an electric motor (when the current value If is positive), the control circuit 1
7, each of the transistors Tx, Ty, Tz, Tu,
By controlling ON / OFF of Tv and Tw, the DC power supplied from the battery 21 is converted into three-phase AC power, and this AC power converts the stator coil 11 of each phase.
The rotor core 6 is rotated by exciting a, 11b, and 11c. On the other hand, when the generator motor 5 is operated as a generator (when the current value If is negative), all the transistors Tx, Ty, Tz, Tu, Tv, are controlled by the control circuit 17.
By turning off Tw, the AC power induced in the stator coils 11a, 11b, 11c of the respective phases is transferred to the diodes Dx, Dy, Dz, Du, Dv, Dw.
Is rectified through to charge the battery 21.

9 and 10 show the behavior when the rotational speed fluctuation suppression control is executed in this way, for example, for a 4-cylinder 4-cycle gasoline engine 1. In FIG. 9, the control cycle is 10 ° CA, and in FIG. 10, the control cycle is 30 °.
It is CA. In any case, the torque generated by the generator motor 5 is actively controlled by feeding back the rotational speed Ne of the engine 1 so as to cancel the fluctuation of the generated torque (rotational speed Ne) of the engine 1. Therefore, the torque generated by the generator motor 5 is adapted to the fluctuation of the rotation speed Ne of the engine 1 (torque fluctuation), and the effect of suppressing the rotation speed fluctuation is improved as compared with the conventional case. in this case,
As is clear from a comparison between the graphs of FIG. 9 and FIG. 10, the shorter the control cycle is, the greater the effect of suppressing the rotation speed fluctuation becomes, and the rotation speed Ne of the engine 1 becomes more stable.

By the way, when a part of the cylinders of the engine 1 misfires, the generated torque of the engine 1 temporarily decreases as shown in FIG. 11 (an example in which the third cylinder misfires). Unless the rotational speed fluctuation suppression control is performed, the engine rotational speed (average value) relatively decreases as shown by the dotted line in FIG. Further, in the conventional rotational speed fluctuation suppression control (two-dot chain line in FIG. 11), the operation mode of the generator motor is simply switched by the crank angle of the engine, and the generated torque of the generator motor is not controlled at all, so misfire may occur. The generated torque of the generator motor does not match the reduced engine rotation speed, but rather the generated torque of the generator motor acts in the direction of increasing the rotation speed fluctuation, and the drop of the engine rotation speed is increased. In the worst case, the engine may stall.

On the other hand, in the rotational speed fluctuation suppression control of the present embodiment, as shown by the solid line in FIG. 11, when the torque generated by the engine 1 temporarily decreases due to a misfire, the generator motor 5 is made to compensate for it. The generated torque increases relatively,
The engine 1 is controlled so as to cancel the variation in the torque generated by the engine 1, and the decrease in the rotation speed Ne of the engine 1 is prevented. The above is not limited to the case of misfire, and can be said when an external load such as a power steering or an air conditioner is input.

In this embodiment, the value If of the current flowing in the field winding 8 of the generator motor 5 is switched stepwise in order to control the torque generated by the engine 1, but this is continuously changed. Alternatively, the field winding 8 may be used.
Control the voltage and duty ratio (on / off duty ratio) applied to the
You may make it carry out WM control.

Further, in this embodiment, the crankshaft 2
By inputting the output pulse signal of the rotary encoder 12 connected to the ECU 13 to the ECU 13, the crank angle and the rotation speed of the engine 1 are detected.
The crank pulse output from the crank angle sensor provided in the ignition distributor is configured to have a high frequency to output a signal of, for example, 36 pulses or more per one revolution of the engine 1, and the pulse signal is input to the ECU 13 to determine the crank angle. The rotation speed of the engine 1 may be detected.

The control cycle is also 10 ° CA and 30 ° CA.
It is needless to say that the crank angle is not limited to 15 ° CA, 20 ° CA, and other crank angles.

In addition, the scope of application of the present invention is not limited to a 4-cylinder engine, but can be applied to engines with other cylinder numbers such as 3-cylinder, 5-cylinder, 6-cylinder, 8-cylinder, etc.
The present invention is not limited to a 4-cycle or 2-cycle gasoline engine, but can be applied to a diesel engine. Further, the configuration of the generator motor 5 may be appropriately changed, and various modifications can be made without departing from the scope of the invention. ..

[0047]

As is apparent from the above description, the present invention feeds back the detected engine speed,
Since the torque generated by the generator motor is calculated and the operation of the generator motor is controlled based on this calculation result, the generated torque of the generator motor is actively controlled according to the fluctuation of the engine rotation speed. Therefore, even when a part of the cylinders of the engine misfires or an external load such as power steering is input, it is possible to effectively suppress the fluctuation of the engine rotation speed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a rotation speed fluctuation suppressing device showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a generator motor

[Fig. 3] Electric circuit diagram of main parts

FIG. 4 is a flowchart showing the processing contents of an engine operating state determination routine.

FIG. 5 is a flowchart showing the processing contents of a rotation speed fluctuation suppression routine.

FIG. 6 is a diagram showing an outline of an idle vibration suppression control study simulation.

FIG. 7 is a graph showing motor torque characteristics.

FIG. 8 is a graph showing generator torque characteristics.

FIG. 9 is a graph showing behavior when controlled with a control cycle of 10 ° CA.

FIG. 10 is a graph showing the behavior when controlled with a control cycle of 30 ° CA.

FIG. 11 is a graph showing behavior when some cylinders of the engine misfire.

[Explanation of symbols]

1 is an engine, 5 is a generator motor, 8 is a field winding, and 11a
11c is a stator coil, 12 is a rotary encoder (rotational speed detection means), 13 is an ECU (rotational speed detection means, generated torque calculation means), 14 is a vehicle speed sensor, 15 is an idle switch, 17 is a control circuit (control means). , 19
Is an inverter / converter, 20 is a current controller (control means), and 21 is a battery.

Claims (1)

[Claims] 1. A system in which fluctuations in engine rotational speed are suppressed by torque generated by a generator-motor, wherein rotational speed detecting means for detecting engine rotational speed and engine rotational speed detected by the rotational speed detecting means are fed back. An engine comprising: a generated torque calculating means for calculating a torque to be generated by the generator motor and a control means for controlling the operation of the generator motor based on a calculation result of the generated torque calculating means. Rotation speed fluctuation suppression device.