JP3610872B2 - Idle rotation speed control device for hybrid vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an idle speed control device for a hybrid vehicle.
[0002]
[Prior art]
There is known a hybrid vehicle that has both an internal combustion engine (engine) and an electric motor (motor) as a prime mover, and is driven by one or both driving forces (see Japanese Patent Laid-Open No. 8-182110).
[0003]
[Problems to be solved by the invention]
By the way, in a hybrid vehicle, in order to suppress the vibration accompanying the fluctuation | variation of the engine torque at the time of idling, it is possible to perform vibration suppression control using the motor which rotates with an engine. That is, as shown in the left half of FIG. 3, a motor torque whose phase is exactly opposite to the periodically varying engine torque is generated, and the fluctuation of the engine torque is offset by this motor torque.
[0004]
However, when the motor average torque per cycle of engine torque fluctuation or a predetermined period becomes a positive value, the high-power battery serving as the motor power source is discharged. When the battery charge (SOC) falls below the minimum charge due to the power consumption of the high-power battery, it is necessary to stop the vibration suppression control using the motor to increase the engine rotation speed and to force the high-power battery to be charged. Therefore, the opportunity to perform vibration suppression control using a motor is limited.
[0005]
Further, since it has been confirmed by experiments that the vibration damping effect is maximized when the motor average torque is zero, the vibration damping effect is likely to be reversed when the motor average torque is not zero.
[0006]
Therefore, in the present invention, when the motor average torque during vibration suppression control using the motor is a positive value, the motor average torque is reduced to zero by controlling the engine torque to increase so that the motor average torque becomes zero. It is an object of the present invention to enable vibration suppression control in a state where the high-power battery is controlled while maximizing vibration control using a motor during idling.
[0007]
[Means for Solving the Problems]
As shown in FIG. 11, the first invention includes an engine 51, a motor 52 that rotates with the engine, a high-power battery 53 that serves as a power source for the motor 52, and the motor in such a direction as to eliminate fluctuations in engine torque during idling. In the idling rotational speed control device for a hybrid vehicle comprising means 54 for performing rotational speed control by means of 52, the engine average torque becomes zero when the motor average torque during rotational speed control by the motor 52 is a positive value. Means 55 for controlling the torque increase side are provided , and the amount of idle air when the engine torque is increased is stored even after the engine is stopped.
[0009]
The second inventions, as shown in FIG. 11 above, the engine 51, a motor 52 rotated together with the engine, and the high voltage battery 53 as a power source of the motor 52, in the direction counteract variations in engine torque during idle In an idle rotation speed control device for a hybrid vehicle comprising means 54 for controlling the rotation speed by the motor 52, the motor average torque becomes zero when the motor average torque during the rotation speed control by the motor 52 is a positive value. A means 55 for controlling the engine torque to be increased is provided. The means for controlling the engine torque to be increased is a throttle control device and a means for controlling the throttle valve opening to increase the throttle valve opening. Ri Do from a, the throttle valve opening when the throttle valve opening is controlled on the side of increasing After stopping of the engine it is also stored.
[0011]
In a third invention, in the first invention, the idle air amount is a sum of an additional idle air amount and a base idle air amount corresponding to the positive motor average torque.
[0012]
In a fourth invention, in the third invention, the base idle air amount is a value set in advance so as to obtain a target idle rotation speed.
[0013]
According to a fifth aspect , in the third aspect , the base idle air amount is a value learned so as to obtain a target idle rotation speed in a state where the motor does not generate torque at the time of factory shipment.
[0014]
【The invention's effect】
According to the first and second inventions, it is possible to perform the rotational speed control by the motor in a state where the average motor torque becomes zero, and thereby, the vibration is controlled to the maximum by the rotational speed control by the motor during idling. And the power consumption of the high-power battery can be suppressed.
[0015]
According to the third and fourth aspects of the invention, the motor average torque can be accurately zero regardless of the magnitude of the motor average torque.
[0016]
According to the fifth aspect of the invention, since the rotational speed control by the motor is stopped when learning the base idle air amount at the time of factory shipment, the rotational speed control by the motor is also performed at the time of learning the base idle air amount at the time of factory shipment. Incorrect learning can be prevented.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 and FIG. 2 show a configuration example of a hybrid vehicle. Each of these is a parallel hybrid vehicle that travels using the power of either one or both of the engine and the motor according to traveling conditions.
[0018]
In FIG. 1, a thick solid line indicates a transmission path of mechanical force, and a thick broken line indicates a power line. A thin line indicates a control line, and a double line indicates a hydraulic system. The power train of the vehicle includes a motor 1, an engine 2, a clutch 3, a motor 4, a continuously variable transmission 5, a speed reducer 6, a differential device 7, and drive wheels 8. The output shaft of the motor 1, the output shaft of the engine 2, and the input shaft of the clutch 3 are connected to each other, and the output shaft of the clutch 3, the output shaft of the motor 4 and the input shaft of the continuously variable transmission 5 are connected to each other. ing.
[0019]
When the clutch 3 is engaged, the engine 2 and the motor 4 serve as a vehicle propulsion source, and when the clutch 3 is released, only the motor 4 serves as a vehicle propulsion source. The driving force of the engine 2 or the motor 4 is transmitted to the drive wheels 8 through the continuously variable transmission 5, the speed reducer 6, and the differential device 7. The continuously variable transmission 5 is supplied with pressure oil from the hydraulic device 9, and the belt is clamped and lubricated. An oil pump (not shown) of the hydraulic device 9 is driven by a motor 10.
[0020]
The motor 1 is mainly used for engine starting and power generation, and the motor 4 is mainly used for vehicle propulsion (power running) and control. The motor 10 is for driving an oil pump of the hydraulic device 9. Further, when the clutch 3 is engaged, the motor 1 can be used for propulsion and braking of the vehicle, and the motor 4 can be used for engine starting and power generation. The clutch 3 is a powder clutch and can adjust the transmission torque. The continuously variable transmission 5 is a continuously variable transmission such as a belt type or a toroidal type, and the gear ratio can be adjusted steplessly.
[0021]
The motors 1, 4, and 10 are driven by inverters 11, 12, and 13, respectively. In the case where a DC electric motor is used for the motors 1, 4 and 10, a DC / DC converter is used instead of the inverter. The inverters 11, 12, and 13 are connected to a high-power battery (42 V battery) 15 through a common DC link 14, and the DC charging power of the high-power battery 15 is converted into AC power and supplied to the motors 1, 4, and 10. At the same time, the AC power generated by the motors 1 and 4 is converted into DC power to charge the high-power battery 15. Since the inverters 11 to 13 are connected to each other via the DC link 14, the power generated by the motor during the regenerative operation can be directly supplied to the motor during the power running operation without going through the high-power battery 15. it can. Various types of batteries such as lithium ion batteries, nickel / hydrogen batteries, lead batteries, and electric double layer capacitors, so-called power capacitors, are applied to the high-power battery 15.
[0022]
A controller 16 includes a microcomputer, its peripheral components, various actuators, and the like. The transmission torque of the clutch 3, the rotational speed and output torque of the motors 1, 4, and 10, the transmission ratio of the continuously variable transmission 5, the engine 2 Controls fuel injection amount, injection timing, ignition timing, etc.
[0023]
As shown in FIG. 2, the controller 16 includes a key switch 20, a select lever switch 21, an accelerator pedal sensor 22, a brake switch 23, a vehicle speed sensor 24, a battery temperature sensor 25, a battery SOC detection device 26, and an engine rotation speed sensor 27. A throttle opening sensor 28 is connected. The key switch 20 is closed when the key of the vehicle is set to the ON position or the START position (hereinafter, the switch closing is referred to as ON and the opening is referred to as OFF). The select lever switch 21 is one of P, N, R, and D switches according to the set position of a select lever (not shown) that switches to any range of parking P, neutral N, reverse R, and drive D. Is turned on.
[0024]
The accelerator pedal sensor 22 detects the amount of depression of the accelerator pedal, and the brake switch 23 detects the amount of depression of the brake pedal (switch ON at this time). The vehicle speed sensor 24 detects the traveling speed of the vehicle, and the battery temperature sensor 25 detects the temperature of the high-power battery 15. Further, the battery SOC detection device 26 detects SOC (State Of Charge) which is a representative value of the actual capacity of the high-power battery 15. Further, the engine rotation speed sensor 27 detects the rotation speed of the engine 2, and the throttle opening sensor 28 detects the throttle valve opening of the engine 2.
[0025]
Also connected to the controller 16 are a fuel injection device 41 of the engine 2, an ignition device 42, a variable valve operating device 43, an electronically controlled throttle control device (driving a butterfly throttle valve using a DC motor as a throttle actuator), and the like. Is done. The controller 16 controls the throttle control device 44 and the fuel injection device 41 so as to obtain a predetermined target torque with the stoichiometric air-fuel ratio or an air-fuel ratio leaner than that as a target to control the throttle valve opening and the fuel to the engine 2. While adjusting the supply amount, the ignition device 42 is driven to control the ignition timing of the engine 2. The controller 16 controls the variable valve operating device 43 to adjust the operating state of the intake / exhaust valves of the engine 2. The controller 16 is supplied with power from a low-voltage auxiliary battery (12V battery) 33.
[0026]
The controller 16 also generates a motor torque having a phase opposite to that of the engine torque in order to suppress vibration associated with fluctuations in engine torque during idling, and cancels periodic fluctuations in engine torque with this motor torque. Next, the rotational speed control of the motor 1 is performed (see FIG. 3). Since the method of controlling the rotational speed using the motor 1 is well known, it will not be described in detail.
[0027]
In this case, when the motor average torque becomes a positive value, the power of the high-power battery 15 is consumed. Therefore, in order to avoid this, the controller 16 sets the motor average torque during the rotation speed control of the motor 1 to a positive value. At this time, the engine torque is controlled to be increased (for example, the intake air amount is increased) so that the motor average torque becomes zero. In this case, since the intake air amount changes according to the throttle valve opening, the intake air amount of the engine is increased by increasing the throttle valve opening.
[0028]
The contents of this control executed by the controller 16 will be described using the flowchart of FIG.
[0029]
FIG. 4 is for calculating the throttle valve target opening during idling, and is executed at regular intervals (for example, every 10 ms).
[0030]
In Step 1, it is checked whether or not the idle speed feedback control condition is satisfied. The feedback control condition is when the following two conditions are satisfied. If any one of them is canceled, the feedback control condition is not satisfied, and the feedback control is stopped.
[0031]
(1) The throttle valve opening is in the idle position.
[0032]
(2) The vehicle speed is below the specified value or the select lever is in the neutral position.
[0033]
When the feedback control condition is satisfied, the process proceeds to step 2 and a flag (additional idle air amount learned flag to be described later in step 11) is used to determine whether or not learning of the additional idle air amount has been completed. When learning of the additional idle air amount is not completed (additional idle air amount learned flag = 0), the process proceeds to step 3 and subsequent steps to learn the additional idle air amount. Specifically, first, in Step 3, the motor 1 current value is sampled. However, it is assumed that the rotational speed control for vibration suppression by the motor 1 is performed during idling. Therefore, the motor 1 current value here is the motor 1 current value during rotation speed control for vibration suppression.
[0034]
The process proceeds to steps 5, 6, and 7 until the number of samples of the motor 1 current value is accumulated. That is, in step 5, the base idle air amount is set as the target idle air amount. The base idle air amount is a value set in advance so as to obtain the target idle rotation speed NSET. Since the target idle speed NSET is a value that varies depending on the water temperature, the air conditioner, the gear position, and the like, the base idle air amount also varies depending on the water temperature, the air conditioner, the gear position, and the like. Here, for simplicity, the case where NSET is a constant value will be described. At this time, the base idle air amount becomes a fixed value.
[0035]
In Steps 6 and 7, the value obtained by searching the table containing FIG. 5 from this target idle air amount is calculated as the throttle valve target opening area, and the value obtained by searching the table containing FIG. 6 from this target opening area is calculated. Calculated as the throttle valve target opening.
[0036]
The throttle valve target opening calculated in this way is converted into a command signal for a DC motor (throttle actuator) and output. If the actual throttle valve opening detected by the throttle opening sensor 28 does not coincide with the target opening, feedback control is performed so as to coincide.
[0037]
On the other hand, when the number of samples of the motor 1 current value has reached a predetermined number, the process proceeds to steps 8-12. That is, in step 8, the motor 1 average torque is calculated using a predetermined number of motor 1 current values (sample values). Since the calculation method of the motor 1 average torque is publicly known, description thereof is omitted.
[0038]
In step 9, a value obtained by searching a table having the contents shown in FIG. 7 from this motor 1 average torque is calculated as an additional idle air amount, and this value is stored in a memory (RAM) in the controller 16 in step 10. This completes the learning of the additional idle air amount, so that the additional idle air amount learned flag is switched from 0 to 1 in step 11.
[0039]
The above-mentioned additional idle air amount is an air amount for additionally generating the motor 1 average torque component (however, the motor average torque is a positive value) during the rotational speed control for vibration suppression. In step 12, the value obtained by adding the additional idle air amount to the base idle air amount is calculated as the target idle air amount, and then the processing in steps 6 and 7 is executed.
[0040]
As shown in FIG. 7, when the motor 1 average torque is a negative value, the additional idle air amount is given as a negative value. This is due to the following reason. When the average torque of the motor 1 is a negative value, the high-power battery 15 is overcharged, and the deterioration of the high-power battery is accelerated, so that the vibration suppression control using the motor is stopped in order to avoid this. The opportunity to perform vibration suppression control is limited. Therefore, in order to make the motor 1 average torque zero even when the motor 1 average torque is a negative value, the engine is obtained by giving a negative value to the additional idle air amount, contrary to when the motor average torque is a positive value. The control is performed so that the torque decreases (see FIG. 10). As a result, deterioration of the high-power battery 15 can be prevented, and the opportunity to perform vibration suppression control is not limited.
[0041]
If the feedback control condition is satisfied even after the additional idle air amount learned flag = 1, the process proceeds from step 2 to steps 13 and 14 from the next time, and the additional idle air amount read from the above memory is set. The target idle air amount is calculated by adding to the base idle air amount. In steps 6 and 7, the throttle valve opening is controlled so that the target idle air amount flows.
[0042]
Thereafter, when the engine 2 is stopped, the additional idle air amount stored in the memory is transferred to the EEPROM so that the value is not lost.
[0043]
Here, the operation of the present embodiment will be described with reference to FIG. 3. The right half of the figure is the case of the present embodiment. According to the present embodiment, when the rotational speed control is performed by the motor 1 for vibration suppression during idling, when the motor 1 average torque is a positive value, the motor 1 having the positive value is increased by increasing the idle air amount. Since an extra amount of the average torque is generated in the engine, it becomes possible to control the rotation speed by the motor 1 in a state where the average torque of the motor 1 becomes zero, and thereby the rotation by the motor 1 at the time of idling. The power consumption of the high-power battery 15 can be suppressed while performing vibration suppression to the maximum by speed control.
[0044]
Since the idle rotation speed is determined by the sum of the engine torque and the motor torque, the idle rotation speed does not change even if the engine is generated in excess by the motor average torque.
[0045]
In an engine equipped with an electronically controlled throttle device, the throttle valve opening is adjusted for each vehicle at the time of shipment from the factory to prevent the target idle speed from being obtained due to a throttle valve installation error or the like. Then, after the target idle rotation speed is obtained, the air amount at this time (that is, the base idle air amount) is learned. In this case as well, the rotation speed control by the motor 1 is performed for vibration suppression. In this case, erroneous learning occurs when the motor average torque has a non-zero value. This is because the base idle air amount should be the value for the engine alone, but during the operation of the motor, the idle rotation speed is determined by the sum of the engine torque and the motor torque. Because it comes. For example, even if the throttle valve opening is the same, when the motor average torque is a positive value, the idle rotation speed increases correspondingly, and when the motor average torque is a negative value, the idle rotation speed decreases correspondingly. To do.
[0046]
Therefore, the rotation speed control by the motor 1 is stopped when learning the base idle air amount at the time of factory shipment.
[0047]
The details of the control executed by the controller 16 will be described in detail with reference to FIG. 8. In step 21, it is determined whether or not an instruction for learning the base idle air amount has been received. The learning instruction is executed by a diagnostic tool or a similar hand tool (not shown). That is, a hand tool communicable with the controller 16 is connected to the controller 16, and the hand tool is operated to instruct the controller 16 to learn the base idle air amount.
[0048]
When the learning instruction is received, the motor 1 torque is set to zero in order to stop the rotational speed control by the motor 1 in step 22.
[0049]
In step 23, whether or not the base idle air amount has been learned is determined from a flag (base idle air amount learned flag in step 35 described later). If the base idle air amount has not yet been learned (base idle air amount learned flag = 0), the routine proceeds to step 24, where it is determined whether or not the idle rotational speed feedback control condition is satisfied. If the feedback control condition is not satisfied, the routine proceeds to step 36 where the throttle valve target opening is maintained the same as the previous time (tTVOz which is the previous value of the throttle valve target opening is directly changed to tTVO which is the current value of the throttle valve target opening. Transfer). A predetermined fixed value is included in the initial value of the throttle valve target opening.
[0050]
When the feedback control condition is satisfied, the routine proceeds to step 25, where the actual engine rotational speed Ne detected by the rotational speed sensor 27 is read, and the absolute value of the deviation between this and the target idle rotational speed NSET is compared with the allowable value ε at step 26. Here, the case where Ne is outside the allowable value beyond NSET will be described. At this time, the process proceeds to step 27, where NSET and Ne are compared. When Ne is lower than NSET, in order to increase Ne to NSET, the throttle valve target opening degree tTVO is increased by a constant value ΔTVO in step 28. As the throttle valve opening increases, the intake air amount increases and the engine speed increases. If the value is still outside the allowable value ε, the process of step 28 is repeated. As a result, Ne eventually settles within the allowable value ε centered on NSET.
[0051]
The same applies when Ne is higher than NSET. In order to lower Ne to NSET, the throttle valve target opening tTVO is decreased by a constant value ΔTVO in step 29. As the throttle valve opening decreases, the amount of intake air decreases and the engine speed decreases. If it is still outside the allowable value ε, the process of step 29 is repeated. As a result, Ne eventually settles within the allowable value ε centered on NSET.
[0052]
When Ne settles within the allowable value ε centered on NSET in this way, the routine proceeds to step 30, and the throttle valve target opening is maintained the same as the previous time. Then, in steps 31 and 32, the throttle valve opening area is calculated by searching a table having the contents shown in FIG. 6 from the throttle valve target opening at that time, and the table having the contents shown in FIG. 5 is further searched from the opening area. By doing so, the idle air amount is calculated. In steps 33 and 34, this idle air amount is put into the base idle air amount, and this base idle air amount is stored in a memory (RAM) in the controller 16. This completes the learning of the base idle air amount. In step 35, the base idle air amount learned flag is switched from 0 to 1.
[0053]
With this base idle air amount learned flag = 1, the process proceeds from step 23 to step 36 from the next time, and the throttle valve target opening is maintained the same as the previous time.
[0054]
When learning of the base idle air amount at the time of shipment from the factory is completed in this way, an instruction to cancel the learning of the base idle air amount is given by the hand tool, and then the hand tool is removed from the controller 16.
[0055]
Thereafter, when the engine 2 is stopped, the base idle air amount stored in the memory (RAM) is transferred to the EEPROM so that the value is not lost.
[0056]
As described above, according to the second embodiment, since the rotation speed control by the motor 1 is stopped when learning the base idle air amount at the time of factory shipment, the rotation speed by the motor 1 is also learned at the time of learning the base idle air amount at the time of factory shipment. Incorrect learning due to control can be prevented.
[0057]
In the embodiment, the additional idle air amount is calculated so that the motor average torque becomes zero when the motor average torque is a positive value, and the additional idle air amount is transferred to the EEPROM so that the value is not lost when the engine is stopped. As explained above, the throttle valve opening when the engine torque is increased so that the motor average torque becomes zero when the motor average torque is a positive value is stored in the EEPROM so that the value does not disappear when the engine is stopped. You can move it.
[0058]
In the embodiment, the torque waveform at the time of rotational speed control by the motor for vibration suppression has been described as a sine curve approximation (see FIG. 3), but is not limited to this, as shown in FIG. The torque waveform may be a rectangular waveform, or the motor rotational speed control may be performed by chopper driving or PWM driving. The point is that the motor torque may be generated so that the phase is opposite to the periodically varying engine torque and the fluctuation of the engine torque is offset.
[0059]
Although the embodiment has been described in the case where an electronically controlled throttle control device is provided, the present invention is also applied to a device provided with an auxiliary air control valve controlled by a controller in a passage that bypasses the throttle valve interlocked with the accelerator pedal. it can.
[0060]
Although the embodiment has been described at the time of idling, the present invention is not limited to idling, but can be similarly applied as long as it is a low load state close to idling.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a configuration example of a hybrid vehicle to which the present invention can be applied.
FIG. 2 is a block diagram of a controller.
FIG. 3 is a waveform diagram showing the operation of the first embodiment when the motor average torque is a positive value.
FIG. 4 is a flowchart showing a control operation performed by a controller.
FIG. 5 is a characteristic diagram showing a relationship between an idle air amount and a throttle valve opening area.
FIG. 6 is a characteristic diagram showing the relationship between the throttle valve opening area and the throttle valve opening.
FIG. 7 is a characteristic diagram showing a relationship between a motor average torque and an additional idle air amount.
FIG. 8 is a flowchart showing a control operation performed by the controller of the second embodiment.
FIG. 9 is a waveform diagram showing the operation of the third embodiment.
FIG. 10 is a waveform diagram showing the operation of the first embodiment when the motor average torque is a negative value.
FIG. 11 is a diagram corresponding to claims of the first invention.
[Explanation of symbols]
1 Motor (motor that rotates with the engine)
2 Engine 15 High-power battery 16 Controller 27 Rotational speed sensor 44 Throttle control device

Claims (5)

Engine,
A motor that goes around with the engine,
A high-power battery that powers this motor,
In an idle rotational speed control device for a hybrid vehicle, comprising: means for performing rotational speed control by the motor in a direction to eliminate fluctuations in engine torque during idling,
Means for controlling the engine torque to be increased so that the motor average torque becomes zero when the motor average torque during the rotation speed control by the motor is a positive value ;
Storing the amount of idle air when the engine torque is increased, even after the engine is stopped,
An idle rotation speed control device for a hybrid vehicle characterized by the above. Engine,
A motor that goes around with the engine,
A high-power battery that powers this motor,
Means for controlling the rotational speed by the motor in such a direction as to eliminate fluctuations in engine torque during idling;
In an idle rotation speed control device for a hybrid vehicle comprising:
Means for controlling the engine torque to be increased so that the motor average torque becomes zero when the motor average torque during the rotation speed control by the motor is a positive value;
The means for controlling the engine torque to increase is as follows:
A throttle control device;
And means for instructing the throttle control device to control the throttle valve opening to the increasing side,
The throttle valve opening when the throttle valve opening is controlled to be increased is stored even after the engine is stopped.
Idle speed control characteristics and to Ruha hybrid vehicle that. The idle air quantity, the positive additional idle air amount corresponding to the average motor torque value and the base idle air amount and the engine idle speed control device for a hybrid vehicle according to claim 1, characterized in that the sum of . 4. The idle rotation speed control device for a hybrid vehicle according to claim 3 , wherein the base idle air amount is a value set in advance so as to obtain a target idle rotation speed. 4. The hybrid vehicle according to claim 3 , wherein the base idle air amount is a value learned so that a target idle rotation speed can be obtained in a state where the motor does not generate torque at the time of factory shipment. Idle speed control device.

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