JPH07208228A - Engine torque fluctuation absorbing device - Google Patents

Abstract

PURPOSE:To provide an engine torque fluctuation absorbing device to absorb the torque fluctuation of the engine in the idling. CONSTITUTION:An engine speed sensor 8 which is provided with a gear on which circumference teeth are provided and which is conventionally mounted on a vehicle to detect the engine speed is made use of as a means to detect the fluctuation of the speed. The timing to operate an alternator 2 to absorb the torque fluctuation and the timing to operate a motor are clarified that they are from the x-th pulse to the y-th pulse counted from the reference pulse which is arbitrarily determined in one rotational fluctuation (e. g. the rotation detecting pulse to be generated when the speed becomes slowest... the longest pulse), and they arc detemined. The order of the speed detecting pulse to be received from the reference pulse is counted, and the operation to be determined corresponding to the order is achieved to realize an appropriate operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine torque fluctuation absorbing device that absorbs torque fluctuations of an engine by operating an alternator directly connected to a crankshaft of the engine as a generator and a motor.

[0002]

2. Description of the Related Art The number of revolutions of an engine during idle operation is substantially constant, but when viewed in detail, the revolution speed fluctuates little by little during one revolution. This fluctuation is due to a torque change when the piston moves up and down. Therefore, the number of fluctuations depends on the number of cylinders connected to the crankshaft of the engine.

FIG. 9 is a diagram showing an example of rotational fluctuations of a four-cylinder engine during idle operation. An example is given in which the engine rotates at 600 rpm on average, that is, the crankshaft makes one rotation in 0.1 s (100 ms). Since there are four cylinders, the rotation fluctuation occurs twice during one rotation.

Since this rotation fluctuation causes vibration and noise of the vehicle body, it is desired that it be as small as possible during idle operation when the vehicle body is stationary. When the vehicle is running, the noise due to the rotation fluctuation accounts for a small proportion of the total noise, and is not so noticeable.

As a method of absorbing the rotation fluctuation during idle operation, an AC machine (eg, a synchronous AC machine) is installed on the crankshaft.
There is known a method of directly connecting and absorbing by this.
FIG. 10 shows a vehicle drive unit in which such an engine torque fluctuation absorbing device is incorporated. In FIG. 10, 1 is an engine, 20 is an alternator section, 21 is a clutch section, 22 is a transmission section, and 23 is a propeller shaft.

An AC machine section 20 is provided between the engine 1 and the clutch section 21, and the rotating shaft of the AC machine section 20 is directly connected to the crankshaft. The principle of absorbing the rotation fluctuation using the AC unit 20 is as follows. That is, when the rotational speed fluctuates so as to increase, the AC generator is operated as a generator to consume the torque and the rotational speed is decreased. On the contrary, when the rotation speed is changing so as to decrease, the AC machine is operated as a motor to apply torque to increase the rotation speed. The operation of the electric motor is performed by converting a DC voltage of a normal battery mounted on the vehicle into an AC voltage by an inverter and applying the AC voltage.

In order to perform the above-mentioned control, it is necessary to detect whether the rotational speed is going up or down, and conventionally, for example, the following method is adopted to detect it. Was there. The first method is to use a sensor that detects the compression point of the engine cycle. The rotation speed takes advantage of the property that it becomes the slowest at the compression point.
The second method is to use a rotation sensor that generates a voltage proportional to the engine speed and detect a change in the voltage. When the voltage change is positive, the rotation speed is increasing, and when the voltage change is negative, the rotation speed is decreasing.

As a conventional document relating to the engine torque fluctuation absorber, there is, for example, Japanese Patent Laid-Open No. 61-223237.

[0009]

However, the method of detecting the rotational speed change employed in the above-described conventional engine torque fluctuation absorbing device has the following problems. In the method of detecting the compression point, the sensor for detecting the compression point is usually not provided in the vehicle but must be specially provided. This increases the cost of the vehicle. Further, when the change is abrupt, it is difficult to accurately adjust the operation switching timing of the AC machine to an appropriate time point.

In the method of detecting the change in the output voltage of the rotation sensor, it takes a certain amount of time to detect the change. Therefore, the operation switching timing of the AC machine can be accurately set at an appropriate time. Difficult to match. Further, when the torque fluctuation absorbing operation is performed, the change in the rotation speed is suppressed, so that the change itself in the output voltage of the rotation sensor becomes small and it becomes difficult to detect the change.
An object of the present invention is to solve the above problems.

[0011]

In order to solve the above-mentioned problems, in the present invention, an AC machine directly connected to an engine is operated as a generator when a rotation fluctuation that increases the rotation speed occurs during idle operation, In the engine torque fluctuation absorber that absorbs the torque fluctuations of the engine by operating the motor when the rotation fluctuations that lower the rotation speed occur during operation, the shaft is directly connected to the crankshaft and the teeth are provided on the circumference. An engine rotation sensor using a gear, a means for detecting an arbitrarily determined reference pulse of the rotation detection pulses from the engine rotation sensor, and a counting for counting the input rotation detection pulse from the reference pulse. Means and an operation pattern that defines an operation pattern for operating the alternator as a generator or as an electric motor according to the pulse order from the reference pulse. A driving pattern table is held, and a driving pattern selecting unit that selects a driving pattern corresponding to the input pulse order is provided.

[0012]

[Operation] As means for detecting fluctuations in rotation speed, the shaft is directly connected to the crankshaft and the teeth are provided on the circumference, which has been conventionally mounted on a vehicle for detecting the engine speed. Utilizes an engine rotation sensor having a gear. If the engine rotation sensor to be used is determined, the number of teeth is determined, and if the type of engine is determined, the number of rotation fluctuations during one rotation is also determined.

The time when the generator should be operated and the time when the electric motor should be operated to absorb the torque fluctuation are generated when a reference pulse (for example, the rotation speed becomes the slowest) is arbitrarily determined during one rotation fluctuation. From the rotation detection pulse (in other words, the pulse with the longest pulse width), it is known from the number of pulses to the number of pulses, so decide it. Then, the order of the input rotation detection pulses from the reference pulse is counted, and the operation determined according to the order is performed, so that the appropriate operation is performed.

Since an existing engine rotation sensor is used as a sensor for determining the operation timing, it is not necessary to provide a special sensor such as a compression point detection sensor,
The cost is low. In addition, since the fluctuation state of the rotation speed is detected only by the number of the pulse input from the reference pulse, it is better than detecting the fluctuation of the rotation speed by checking the voltage change proportional to the rotation speed. , Detection time is short. Further, since it is sufficient to detect the pulse order, the detection is extremely easy.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. (Description of Overall Configuration) FIG. 1 is a diagram showing an embodiment of an engine torque fluctuation absorbing device of the present invention. In FIG. 1, 1
Is an engine, 2 is an AC machine, 2-1 is a field coil, 3 is a rotor position detector, 4 is a current detector, 5 is an inverter, 6
Is a switching unit, 7 is a rectifier circuit, 8 is an engine rotation sensor, 9 is a voltage regulator, 10 is an inverter control circuit, 11 is an overall control unit, 12 is a converter control circuit, 1
3 is a boost converter, and 14 is a battery. The diode included in the lower half of the inverter 5 is also used for performing the rectifying operation together with the rectifying circuit 7.

As the AC machine 2, for example, a synchronous AC machine is used. The voltage regulator 9 controls the current to the field coil 2-1. A power MOSFET, for example, is used as the switching unit 6 in the inverter 5.
This is a structure in which a reverse diode is effectively formed between the source and the drain. Power M
The OSFET becomes conductive when a gate signal is input to its gate. The conduction direction is opposite to that of the diode.

The gate signal is given from the inverter control circuit 10 when the inverter 5 tries to generate an alternating current. The rotor position detector 3 detects the rotational position of the rotor, and with reference to the detection signal from here,
The timing (phase) of applying the gate signal to each switching unit 6 is determined. When a field current is passed through the field coil 2-1 and an alternating current from the inverter 5 is applied to the alternating current machine 2, the alternating current machine 2 is operated by a motor. When the field current is passed but the alternating current is not applied, the generator is operated. When the field current is not passed, the AC machine 2 rotates as a mere flywheel.

The boost converter 13 is provided to boost and charge the battery 14 with the output voltage of the rectifier circuit 7. The boost converter 13 is not essential because it can be charged without boosting. A well-known structure can be applied as the boost converter 13. The advantages of boosting and charging are as follows.

The first advantage is that more energy is recovered in the battery. Without the boost converter 13, if the output voltage of the rectifier circuit 7 becomes lower than the battery voltage, charging cannot be performed. However, with the boost converter 13, even if the output voltage of the rectifier circuit 7 becomes lower than the battery voltage, charging can be continued as long as the boosted voltage is higher than the battery voltage.

The second advantage is that the torque fluctuation is well absorbed. Since the voltage is increased by the boost converter 13, a battery having a higher rated voltage than the conventional battery can be used as the battery 14. When the rated voltage is increased, a large electric motor current can flow when the inverter 5 converts the alternating current into the alternating current to drive the alternating current motor 2. Then, high torque can be generated,
Good absorption of torque fluctuations.

A third advantage is that the boost converter can turn the output on and off for an arbitrary time, and therefore the generator can be operated only during the period when the engine speed is increasing.

A rotation detection pulse is input from the engine rotation sensor 8 to the general control section 11. Further, various vehicle information and a rectified output voltage (V) detection signal are input. The integrated control unit 11 analyzes the input information and issues a command to the voltage regulator 9, the inverter control circuit 10, the converter control circuit 12 and the like to cause the control operation. For example, when it is detected that the vehicle has stopped and started idle operation, a change in rotation speed is detected and a command is issued to the inverter control circuit 10, the converter control circuit 12, etc.,
The control operation is performed to absorb the torque fluctuation of the engine.

That is, when the rotational speed fluctuates so as to increase, the AC machine 2 is operated as a generator. The generated voltage is rectified, boosted by the boost converter 13, and the battery 14 is boosted.
Recharges, consumes the energy of the torque that is about to increase and reduces the speed. On the contrary, when the rotation speed is changed so as to decrease, the voltage of the battery 14 is converted into alternating current by the inverter 5, and the alternating current is applied to the alternating current machine 2 to operate the electric motor. The engine 1 is given torque, and the rotation speed increases.

(Regarding Rotational Fluctuation Detecting Means) In the present invention, a known engine rotation sensor 8 is used as the rotational fluctuation detecting means. FIG. 2 shows the configuration of the engine rotation sensor. 8-1 is a gear, 8-2 is a shaft, 8-3 is a magnet, and 8-4 is a coil. The gear 8-1 is a gear made of a magnetic material, and for example, an engine ring gear or a PTO (Power Take Off) gear can be used. The shaft 8-2 is directly connected to the crankshaft of the engine.

When the gear 8-1 rotates, the magnetic flux interlinking with the coil 8-4 changes depending on whether a tooth comes directly below the magnet 8-3 or a groove comes. The voltage induced in the pulse periodically changes like a pulse as the tooth moves. When the engine rotation sensor 8 having such a configuration is used for the original purpose of detecting the engine rotation speed, the rotation speed is detected by counting the number of generated pulses.

However, the pulse generated is not so utilized for the engine torque fluctuation absorber of the present invention. In the present invention, it is used to detect which period of one cycle of rotation fluctuation. Therefore, among the pulses generated during one cycle of the rotation fluctuation, a pulse located at a position convenient for counting the pulses within the cycle is determined as the reference pulse. For example, measure the pulse width,
The longest pulse is defined as the reference pulse.

When the rotation speed is high, one tooth has a magnet 8
Since the time to move immediately below -3 is short, the width of the pulse output from the coil 8-4 is short. When the rotation speed is slow, the pulse width becomes long because the pulse moves slowly.
Since the longest pulse is specified as one in one cycle, it can be used as a reference pulse.

When the mechanical structure of the gear 8-1 is determined, the number of surrounding teeth is determined, and thus the number of pulses emitted in one rotation is determined. Assuming that the number of teeth is 40, 40 pulses are generated in one rotation. The cycle of torque fluctuation is determined by the number of cylinders in the engine, but if there are four cylinders,
As shown in FIG. 9, since there are two fluctuations in one rotation, the fluctuation cycle is a half rotation period. In terms of the number of pulses, this is a period in which 20 pulses are output.

FIG. 3 is a diagram showing the relationship between the rotation fluctuation and the length of the rotation detection pulse. Curve a is similar to the curve in FIG. The rotation speed is slowest at points A and C, and fastest at point B. B is a pulse generated based on the detection signal of the engine rotation sensor 8 and has a slowest rotation speed A,
The pulse width becomes maximum at C and becomes minimum at point B where the rotation speed is fastest.

(Regarding Operation Pattern of Alternator) In the following description, the case where the longest pulse is selected as the reference pulse will be described as an example. 20 pulses within one fluctuation cycle
Each piece is sequentially numbered with the longest pulse as the head. If the first number is 0, the last pulse number is 19. As can be seen from FIG. 9, in order to absorb the torque fluctuation, it is required to operate the AC machine 2 as a generator in the range of points A to B and to operate the electric motor in the range of points B to C. However, the time can be specified by the pulse number. This identification can be performed in advance. This is because when the engine type is determined (eg, the number of cylinders, etc.) and the number of teeth of the gear 8-1 is determined, the variation pattern as shown in FIG. 3 is known in advance. FIG. 4 shows the pattern.

FIG. 4 is a diagram showing an example of the operation pattern of the AC machine. The number of teeth of the gear 8-1 corresponding to one cycle of rotation fluctuation is 20. The ◯ mark indicates that the operation is executed. That is, when the order of the pulses detected by the engine rotation sensor 8 is 1 to 6, the generator is operated, and when the order is 14 to 19, the motor is operated. This is because it is determined that the engine of this example does not require any operation, although some pulses are not marked with a circle. Depending on the engine type, all pulses may be marked as either run.

(Selection of Operation Pattern) As described above, according to the present invention, since a predetermined reference pulse is found, and in what number pulse is counted from that, what kind of pattern the operation is to be performed is selected. It is necessary to perform the operation of processing the detection pulse and selecting the operation pattern.
Such operation is performed in the integrated control unit 11.

FIG. 5 is a diagram showing a configuration of a portion for selecting an operation pattern, which is configured in the integrated control unit 11.
The reference numerals correspond to those in FIG. 1, and 15 is a counter, 16 is an operation pattern selection unit, and 17 is an initial value setting unit. The rotation detection pulse from the engine rotation sensor 8 is the counter 1
5 and the initial value setting unit 17 are input.

The initial value setting section 17 has only to work for several revolutions after the engine starts to rotate. The contents are
It substantially constitutes a reference pulse finding section, and when the reference pulse is found, the value of the counter 15 is reset (how to find will be described later with reference to FIG. 6). That is,
The pulse number is “0”. Which pulse is the reference pulse can be detected if it takes several revolutions. Once the reference pulse is detected, it is possible to know which pulse is the reference pulse as long as the pulse counting is continued.

Because the number of gear teeth is fixed,
This is because the number of pulses in one cycle is fixed (20 teeth
If it is an individual, every 20th pulse is the reference pulse). Therefore, the initial value setting unit 17 is set to 1 after the engine is started.
It suffices to operate only for a period in which the reference pulse can be detected.

As the counter 15, it is desirable to use a ring counter or the like that is automatically reset by the number of pulses in one cycle of rotation fluctuation. For example, if the number of pulses in one cycle is 20, the counter is reset to 0 when 20 pulses are input. Of course, the initial value setting unit 17
When the reset signal is input from, the configuration is such that it is reset. The output of the counter 15 as described above informs what number pulse the input rotation detection pulse is counted from the reference pulse.

The operation pattern selector 16 stores the operation pattern of the AC machine 2 shown in FIG. 4, and selects the operation pattern corresponding to the count value of the counter 15.
An operation command is issued to the inverter control circuit 10 and the converter control circuit 12 according to the selected operation pattern.

FIG. 7 is a flow chart for explaining the above operation until the operation pattern is selected. Step 1 ... When the reference pulse (eg, longest pulse) is detected by the initial value setting unit 17, the pulse number M is set to 0.
And Step 2 ... Read the operation pattern table according to the order of the pulses output from the counter 15.

Step 3: Check whether the pulse number is within the range in which the generator should be operated. This is performed by the operation pattern selection unit 16. Step 4 ... If it is within that range, the converter control circuit 12 is instructed to operate the generator. Step 5: Check whether the pulse sequence is within the range of the motor operation. This is also performed by the operation pattern selection unit 16. Step 6 ... If it is within the range, a command is issued to the inverter control circuit 10 to operate the electric motor.

Step 7 ... When the next rotation detection pulse is input, the pulse number M is incremented by one. This is done by the counter 15. Step 8 ... The pulse number M is the last number M _{E of} one cycle.
To see if it has reached If not reached, the process directly returns to step 2. Step 9 ... If it has been reached, the pulse number M is reset (M = 0) and the process returns to Step 2.

FIG. 6 is a flow chart for explaining the operation for finding the longest pulse when the longest pulse is the reference pulse. This operation is performed by the initial value setting unit 17. Step 1 ... Focusing on an arbitrary pulse of the rotation detection pulse input, the pulse number N is set to 0. Step 2 ... A parameter T indicating the pulse width is provided in advance, and the pulse width T _N of the pulse of the number _N is put therein.
Note that T _N is a pulse width as shown in FIG. 8 here.

Step 3 ... A parameter T _MAX of the pulse width of the longest pulse is provided in advance, and it is checked whether the new value of T obtained in step 2 is larger than T _MAX . If not, proceed to step 5. Step 4 ... If T _MAX is larger than T _MAX , set T _MAX to T (= T
_N ) value (← new longest value) is updated. Also, a parameter N ₀ indicating the number of the longest pulse is provided in advance, and the number N of the pulse used for updating is put in this. As a result, the longest pulse width of the pulses that have been input so far is T _N , and that pulse is the Nth pulse counted from the pulse input in step 1 as the 0th pulse. I understand.

Step 5: When the next pulse is input, the pulse number is incremented by 1. Step 6 ... Checks whether the increased pulse number is equal to the final number N _E determined by the number of gear teeth or the like. If they are not equal, the process returns to step 2 and the operation is repeated. When they are equal, end. By looking at N ₀ at the end, it is possible to know what number pulse was the longest. If it is known, the number of pulses may be counted after that, and when the pulse is input, a reset signal may be sent to the counter 15.

As described above, a predetermined reference pulse is found from the pulses sent from the engine speed sensor 8, and the reference pulse is calculated from that pulse to count the order of the input pulses. Then, referring to the engine type and the like, the operation pattern is determined according to the operation pattern table that defines what kind of operation the AC machine 2 should be operated at at what number of pulses.

In the above-described embodiment, the longest pulse during one rotation fluctuation is used as the reference pulse, but the reference pulse may be the starting point of pulse counting during one rotation fluctuation. Therefore, any other pulse, for example, the shortest pulse may be used as the reference pulse.

[0046]

As described above, according to the engine torque fluctuation absorbing apparatus of the present invention, the existing engine rotation sensor is used as the sensor for determining the operating time of the AC machine. It is not necessary to provide a special sensor such as, and the cost is low. Also, since the fluctuation state of the rotation speed is detected only by the number of the pulse input from the reference pulse, it is better than detecting the fluctuation of the rotation speed by checking the voltage change proportional to the rotation speed. , Detection time is short.

[Brief description of drawings]

FIG. 1 is a diagram showing an engine torque fluctuation absorbing device of the present invention.

FIG. 2 is a diagram showing a configuration of an engine rotation sensor.

FIG. 3 is a diagram showing a relationship between a rotation fluctuation and a length of a rotation detection pulse.

FIG. 4 is a diagram showing an example of an operation pattern table of an AC machine.

FIG. 5 is a diagram showing a configuration of a portion for selecting an operation pattern.

FIG. 6 is a flowchart illustrating an operation for finding the longest pulse.

FIG. 7 is a flowchart illustrating an operation up to selecting an operation pattern.

FIG. 8 is a diagram showing a pulse length.

FIG. 9 is a diagram showing an example of rotational fluctuation of a 4-cylinder engine during idle operation.

FIG. 10 is a diagram showing a vehicle drive unit in which an engine torque fluctuation absorbing device is incorporated.

[Explanation of symbols]

1 ... Engine, 2 ... Alternator, 2-1 ... Field coil, 3 ...
Rotor position detector, 4 ... Current detector, 5 ... Inverter,
6 ... Switching unit, 7 ... Rectifier circuit, 8 ... Engine rotation sensor, 8-1 ... Gear, 8-2 ... Shaft, 8-3 ... Magnet, 8-4 ... Coil, 9 ... Voltage regulator, 10 ... Inverter control Circuit, 11 ... Overall control unit, 12 ... Converter control circuit, 13 ... Boost converter, 14 ... Battery, 15 ...
Counter, 16 ... Operation pattern selection section, 17 ... Initial value setting section, 20 ... Alternator section, 21 ... Clutch section, 22 ... Transmission section, 23 ... Propeller shaft

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomo Tozawa 8 Satoshi, Fujisawa-shi, Isuzu Motors Co., Ltd. Fujisawa Plant (72) Inventor Keiichi Nishioka 3-25-1, Tonomachi, Kawasaki-ku, Kawasaki Isuzu Motors Kawasaki (72) Inventor Kazumi Nishizawa 1-12-11 Higashirokugo, Ota-ku, Tokyo Nikko Electric Industry Co., Ltd. (72) Inventor Toshinori Hirai 1-12-11 Higashirokugo, Ota-ku, Tokyo Nikko Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. An alternator directly connected to an engine is operated as a generator when a rotational fluctuation that increases a rotational speed occurs during idle operation, and an electric motor when a rotational fluctuation that decreases a rotational speed occurs during idle operation. By driving
In an engine torque fluctuation absorber that absorbs torque fluctuations of an engine, a rotation sensor that outputs a plurality of pulses to equally divide the rotation angle of the engine as the engine rotates, and a rotation detection pulse from the engine rotation sensor. Means for detecting an arbitrarily determined reference pulse, counting means for counting an input rotation detection pulse by counting from the reference pulse, and whether to operate the alternator according to the pulse order from the reference pulse as a generator. An engine torque fluctuation absorbing device, comprising: an operation pattern table that defines an operation pattern of whether or not to operate a motor, and an operation pattern selection unit that selects an operation pattern corresponding to an input pulse order. .