JP2007210609A - Controller and control method for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve satisfactory accelerating performance in a hybrid car. <P>SOLUTION: A controller for a vehicle is provided with: an engine 100; a motor generator 500 for assisting the engine 100; and a fluid coupling 200 for transmitting a driving power inputted from the engine and the motor to an automatic transmission 300. The controller also includes an ECT_ECU 400 for setting the level of the assist of the driving power by the motor generator 500 so as to correspond to the rate of the input number of revolutions and the output number of revolutions in the fluid coupling, and to a gear ratio in the start, and for adjusting the level of the assist of the driving force by the motor generator 500 so as to correspond to the level of acceleration and the start gear ratio required for the vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device and a control method for improving the acceleration performance of a vehicle, and more particularly to a control device and a control method for improving acceleration performance at the time of start of a vehicle having two power sources.

  There is a vehicle called a hybrid type equipped with an engine and an electric motor. This vehicle controls the engine and the electric motor so as to improve the fuel consumption according to the driving situation.

  Japanese Patent Laid-Open No. 3-121928 (Patent Document 1) discloses such a hybrid powertrain. The power train disclosed in this publication includes an engine, a motor, and a control circuit that assists the engine by driving the motor when the load on the engine exceeds a predetermined value.

According to the power train disclosed in this publication, when the engine load exceeds a predetermined value, the motor is driven and the engine is assisted. Therefore, the vehicle is driven without using the full load region of the engine. be able to. Further, when the vehicle is braked, the secondary battery is charged with electric power generated by causing the motor to function as a generator, and electric power is supplied from the secondary battery to the motor when assisting the engine. Thereby, the content of nitrogen oxides and carbon monoxide contained in the exhaust gas discharged from the engine can be reduced, and the fuel efficiency can be improved.
Japanese Patent Laid-Open No. 3-121928

  However, in the power train described in the above-mentioned publication, the torque transmitted to the drive wheels differs depending on the gear ratio at the start of the vehicle. Therefore, the desired torque can be appropriately transmitted without considering the gear ratio of the start gear. become unable.

  The present invention has been made to solve the above-described problems, and has sufficient acceleration performance in a vehicle equipped with a first power source and a second power source that assists the first power source. It is to provide a vehicle control device and a control method that are realized.

  A control device according to a first aspect of the present invention is a vehicle equipped with a first power source, a second power source that assists the first power source, and a transmission that transmits the driving force from the power source. It is a control device. The control device includes setting means for setting the degree of assist of the driving force by the second power source in accordance with the gear ratio of the transmission when the vehicle starts.

  According to the first invention, the setting means is configured such that, for example, the smaller the gear ratio of the transmission used when the vehicle starts, the smaller the torque transmitted to the drive wheels by the first power source. The assist amount is set so as to increase the degree of assisting the first power source by the power source. That is, a desired acceleration can be generated by assisting the driving force by the second power source in accordance with the gear ratio of the transmission when the vehicle starts. As a result, it is possible to provide a vehicle control device that realizes sufficient acceleration performance in a vehicle equipped with two power sources.

  A control device according to a second aspect of the present invention is a vehicle equipped with a first power source, a second power source that assists the first power source, and a transmission that transmits driving force from the power source. It is a control device. The control device includes a calculating means for calculating the degree of acceleration required for the vehicle, a second speed according to the degree of acceleration calculated by the calculating means and the gear ratio of the transmission when the vehicle starts. Setting means for setting the degree of assist of the driving force by the power source.

  According to the second invention, for example, in order to achieve a good acceleration, the setting means causes the second power source to increase as the degree of acceleration increases or as the gear ratio of the transmission when the vehicle starts. The assist amount is set so as to increase the degree of assisting the first power source. That is, a desired acceleration can be generated by assisting the driving force by the second power source in accordance with the degree of acceleration demand by the driver and the gear ratio of the transmission when the vehicle starts. it can. As a result, it is possible to provide a vehicle control device that realizes sufficient acceleration performance in a vehicle equipped with two power sources.

  In the control device according to the third invention, in addition to the configuration of the second invention, the calculating means includes a ratio satisfied by the actual acceleration with respect to the requested acceleration required for the vehicle, the requested acceleration, and the actual acceleration. Means for calculating a degree of acceleration representative of any of the differences.

  According to the third invention, in a vehicle equipped with two power sources, using the ratio of the actual acceleration to the requested acceleration and the degree of acceleration calculated based on either the difference between the requested acceleration and the actual acceleration. It is possible to provide a vehicle control device that realizes sufficient acceleration performance.

  In the control device according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the setting means is means for setting a plurality of change characteristics having different degrees of assist corresponding to the gear ratio. including.

  According to the fourth invention, the setting means sets a plurality of change characteristics having different degrees of assist with respect to the gear ratio. Depending on the degree of acceleration requested by the driver of the vehicle, the degree of assist is set by selecting one change characteristic from among a plurality of change characteristics. Thus, the degree of assist can be set so that the most suitable acceleration is obtained based on the accelerator opening representing the degree of acceleration and the rate of change of the accelerator opening.

  In the control device according to the fifth invention, in addition to the configuration of any one of the first to third inventions, the setting means sets means for setting a plurality of change characteristics having different degrees of assist corresponding to the gear ratio. And means for setting the degree of assist of the driving force by the second power source by selecting one of the plurality of change characteristics.

  According to the fifth invention, the setting means sets a plurality of change characteristics having different degrees of assist with respect to the gear ratio. The setting means sets the degree of assist by selecting one change characteristic from a plurality of change characteristics according to the degree of acceleration requested by the driver of the vehicle. Thus, the degree of assist can be set so that the most suitable acceleration is obtained based on the accelerator opening representing the degree of acceleration and the rate of change of the accelerator opening.

  In the control device according to the sixth invention, in addition to the configuration of any one of the second to fifth inventions, the setting means assists the driving force by the second power source in response to the high degree of acceleration. Means for setting so as to increase the degree of.

  According to the sixth aspect of the invention, the desired acceleration feeling can be obtained by setting the degree of assist of the driving force by the second power source to be greater as the requested degree of acceleration is greater.

  In the control device according to the seventh invention, in addition to the configuration of any one of the second to fifth inventions, the setting means assists the driving force by the second power source in response to a small degree of acceleration. Means for setting so as to reduce the degree of.

  According to the seventh aspect, the desired acceleration feeling can be obtained by setting the degree of assist of the driving force by the second power source to be smaller as the requested degree of acceleration is smaller.

  In addition to the configuration of any one of the first to seventh inventions, the control device according to the eighth invention controls a vehicle in which the first power source is an engine and the second power source is an electric motor. The setting means includes means for setting the amount of torque generated by the electric motor.

  According to the eighth invention, a desired acceleration feeling can be obtained in a hybrid vehicle equipped with an engine and an electric motor.

  In addition to the configuration of any one of the first to eighth aspects, the control device according to the ninth aspect determines whether to set the degree of assist of the driving force by the second power source by the setting means. The determination means is further included.

  According to the ninth invention, even if acceleration is required by the driver, for example, when the speed is relatively high, assisting the first power source with the second power source may cause energy loss. obtain. At this time, since there are cases where it is disadvantageous in terms of acceleration time and fuel efficiency, the determination means determines whether or not to execute the assist by the second power source.

  In addition to the structure of 9th invention, the control apparatus which concerns on 10th invention further contains the detection means for detecting the vehicle speed of a vehicle. The determining means includes means for determining whether or not to set the degree of assist of the driving force by the second power source based on the vehicle speed detected by the detecting means.

  According to the tenth invention, even if acceleration is required by the driver, when the vehicle speed is relatively high, assisting the first power source with the second power source causes energy loss. At this time, since there are cases where it is disadvantageous in terms of acceleration time and fuel efficiency, the determination means determines whether or not to execute the assist by the second power source based on the speed of the vehicle.

  In addition to the configuration of the tenth invention, the control device according to the eleventh invention is configured such that when the vehicle speed is low, the determination means sets the degree of assist of the driving force by the second power source by the setting means. When the value is high, the setting means includes a means for determining to stop the setting of the degree of assist of the driving force by the second power source.

  According to the eleventh aspect, even if acceleration is requested by the driver, when the vehicle speed is relatively high, assisting the first power source with the second power source causes energy loss. Therefore, the determination means causes the second power source to assist when the vehicle speed is low, and stops the assist execution by the second power source when the vehicle speed is high. Assist by the power source can be executed.

  A control method according to a twelfth aspect of the invention is a vehicle equipped with a first power source, a second power source that assists the first power source, and a transmission to which driving force from the power source is transmitted. It is a control method. This control method includes a setting step of setting the degree of assist of the driving force by the second power source in accordance with the gear ratio of the transmission when the vehicle starts.

  According to the twelfth invention, the setting step includes the second power source because, for example, the smaller the gear ratio of the transmission when the vehicle starts, the smaller the torque transmitted to the drive wheels by the first power source. Thus, the assist amount is set so as to increase the degree of assisting the first power source. That is, a desired acceleration can be generated by assisting the driving force by the second power source in accordance with the gear ratio of the transmission when the vehicle starts. As a result, it is possible to provide a vehicle control method that realizes sufficient acceleration performance in a vehicle equipped with two power sources.

  According to a thirteenth aspect of the present invention, there is provided a control method for a vehicle equipped with a first power source, a second power source that assists the first power source, and a transmission to which driving force from the power source is transmitted. It is a control method. This control method includes a calculation step for calculating a degree of acceleration required for the vehicle, a second power according to the degree of acceleration calculated in the calculation step and the gear ratio of the transmission when the vehicle starts. And a setting step for setting the degree of assist of the driving force by the source.

  According to the thirteenth aspect, the setting step is performed by the second power source, for example, in order to achieve good acceleration, the greater the degree of acceleration, the smaller the gear ratio of the transmission when the vehicle starts. The assist amount is set so as to increase the degree of assisting the first power source. That is, a desired acceleration can be generated by assisting the driving force by the second power source in accordance with the degree of acceleration demand by the driver and the gear ratio of the transmission when the vehicle starts. it can. As a result, it is possible to provide a vehicle control method that realizes sufficient acceleration performance in a vehicle equipped with two power sources.

  In the control method according to the fourteenth invention, in addition to the configuration of the thirteenth invention, the calculating step includes a ratio satisfied by the actual acceleration with respect to the requested acceleration required for the vehicle, the requested acceleration, and the actual acceleration. Calculating a degree of acceleration representing any of the differences.

  According to the fourteenth aspect of the invention, in a vehicle equipped with two power sources, using the ratio of the actual acceleration to the requested acceleration and the degree of acceleration calculated based on either the difference between the requested acceleration and the actual acceleration. It is possible to provide a vehicle control method that realizes sufficient acceleration performance.

  In the control method according to the fifteenth invention, in addition to the configuration of any of the twelfth to fourteenth inventions, the setting step includes a step of setting a plurality of change characteristics having different degrees of assist corresponding to the gear ratio. .

  According to the fifteenth aspect, in the setting step, a plurality of change characteristics having different degrees of assist with respect to the gear ratio are set. Depending on the degree of acceleration requested by the driver of the vehicle, the degree of assist is set by selecting one change characteristic from among a plurality of change characteristics. Thus, the degree of assist can be set so that the most suitable acceleration is obtained based on the accelerator opening representing the degree of acceleration and the rate of change of the accelerator opening.

  In the control method according to the sixteenth invention, in addition to the configuration of any one of the twelfth to fourteenth inventions, the setting step includes a step of setting a plurality of change characteristics having different degrees of assist corresponding to the gear ratio; Selecting a change characteristic of one from a plurality of change characteristics to set the degree of assist of the driving force by the second power source.

  According to the sixteenth aspect, a plurality of change characteristics having different degrees of assist are set in the setting step. The setting step sets the degree of assist by selecting one change characteristic from among a plurality of change characteristics according to the degree of acceleration requested by the driver of the vehicle. Thus, the degree of assist can be set so that the most suitable acceleration is obtained based on the accelerator opening representing the degree of acceleration and the rate of change of the accelerator opening.

  In the control method according to the seventeenth invention, in addition to the configuration of any of the thirteenth to sixteenth inventions, the setting step assists the driving force by the second power source in response to a high degree of acceleration. A step of setting so that the degree of is increased.

  According to the seventeenth aspect, the desired acceleration feeling can be obtained by setting the degree of assist of the driving force by the second power source to be larger as the requested degree of acceleration is larger.

  In the control method according to the eighteenth invention, in addition to the configuration of any of the thirteenth to sixteenth inventions, the setting step assists the driving force by the second power source in response to a small degree of acceleration. A step of setting so that the degree of is reduced.

  According to the eighteenth aspect, the desired acceleration feeling can be obtained by setting the degree of assist of the driving force by the second power source to be smaller as the requested degree of acceleration is smaller.

  A control method according to a nineteenth aspect of the invention controls a vehicle in which the first power source is an engine and the second power source is an electric motor in addition to the configuration of any of the twelfth to eighteenth aspects of the invention. The setting step includes a step of setting the amount of torque generated by the electric motor.

  According to the nineteenth invention, a desired acceleration feeling can be obtained in a hybrid vehicle equipped with an engine and an electric motor.

  In the control method according to the twentieth invention, in addition to the configuration of any of the twelfth to nineteenth inventions, it is determined whether or not to set the degree of assist of the driving force by the second power source in the setting step. A determination step is further included.

  According to the twentieth invention, even if acceleration is requested by the driver, for example, when the speed is relatively high, assisting the first power source with the second power source may cause energy loss. obtain. At this time, since there may be disadvantages in terms of acceleration time and fuel efficiency, it is determined in the determination step whether or not to assist with the second power source.

  The control method according to the twenty-first aspect of the invention further includes a detection step of detecting the vehicle speed in addition to the configuration of the twentieth aspect of the invention. The determination step includes a step of determining whether or not to set the degree of assist of the driving force by the second power source based on the vehicle speed detected in the detection step.

  According to the twenty-first aspect, even if acceleration is requested by the driver, when the vehicle speed is relatively high, assisting the first power source with the second power source causes energy loss. At this time, since there are cases where it is disadvantageous in terms of acceleration time and fuel efficiency, it is determined in the determination step whether or not the assist by the second power source is executed based on the speed of the vehicle. .

  In the control method according to the twenty-second invention, in addition to the structure of the twenty-first invention, the determining step sets the degree of assist of the driving force by the second power source in the setting step when the vehicle speed is low. When the vehicle speed is high, the setting step includes a step of determining to stop the setting of the degree of assist of the driving force by the second power source.

  According to the twenty-second aspect, even if acceleration is requested by the driver, when the vehicle speed is relatively high, assisting the first power source with the second power source causes energy loss. Therefore, in the determination step, the assist by the second power source is executed when the vehicle speed is low, and the assist execution by the second power source is stopped when the vehicle speed is high. Assist by two power sources can be executed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  Hereinafter, a power train of a vehicle equipped with a control device according to an embodiment of the present invention will be described. In the following description, the fluid coupling is described as a fluid coupling with a lock-up clutch, and the transmission is described as an automatic transmission. However, the present invention is not limited to this. For example, the fluid coupling may be a torque converter having a torque amplification function, and the transmission may be a continuously variable transmission (CVT).

  With reference to FIG. 1, the power train of the vehicle including the control device according to the present embodiment will be described. The control apparatus according to the present embodiment is realized by ECT_ECU (Electronic Controlled Automatic Transmission_Electronic Control Unit) 400 shown in FIG.

  As shown in FIG. 1, this vehicle includes an engine 100, a fluid coupling 200, an automatic transmission 300, a motor generator 500 that assists the engine 100, and an inverter 600 that controls the motor generator 500. . The output shaft of the engine 100 is connected to the input shaft of the fluid coupling 200 via the engine inertia 110 schematically represented. Engine 100 and fluid coupling 200 are connected by a rotating shaft 150. Therefore, the output shaft rotational speed N (E) of the engine 100 and the input shaft rotational speed N (P) of the fluid coupling 200 are the same. Further, the output torque of engine 100 is represented as T (E), and the input torque to fluid coupling 200 is represented as T (P).

  Motor generator 500 is configured to transmit torque to rotating shaft 150 that connects engine 100 and fluid coupling 200. The motor generator 500 operates as a motor to assist the engine 100 in order to obtain a desired acceleration when the vehicle starts. Also, during regenerative braking, it operates as a generator to convert kinetic energy into electrical energy and recover it.

  The fluid coupling 200 includes a lock-up clutch 210 and includes a pump impeller 220 and a turbine impeller 230. The fluid coupling 200 and the automatic transmission 300 are connected by a rotating shaft 250. The output shaft rotational speed of the fluid coupling 200 is represented as N (T), and the output torque of the fluid coupling 200 is represented as T (T).

  The ECT_ECU 400 that controls these powertrains receives the pump rotation speed N (P), turbine rotation speed N (T), accelerator opening, vehicle speed, vehicle acceleration, throttle opening, AT signal, and shift position signal. . Further, a lockup clutch engagement pressure signal is output from the ECT_ECU 400 to the lockup clutch 210 of the fluid coupling 200. An AT control signal is output from the ECT_ECU 400 to the automatic transmission 300. An assist amount instruction signal is output from the ECT_ECU 400 to the inverter 600.

  In FIG. 1, the power of the engine 100 or the engine 100 and the motor generator 500 is transmitted to drive wheels connected via an automatic transmission 300 including a fluid coupling 200 with a lock-up clutch. The fluid coupling 200 is connected to a pump impeller 220 fixed to a crankshaft (input shaft of the fluid coupling 200) 150 of the engine 100 and an input shaft (output shaft of the fluid coupling 200) 250 of the automatic transmission 300. And a lockup clutch 210 that directly connects the pump impeller 220 and the input shaft 250.

  When the vehicle starts, the lockup clutch 210 is unlocked and the lockup clutch 210 is slip-controlled, so that the torque transmitted from the engine 100 to the automatic transmission 300 is increased smoothly. When the vehicle is stopped, the lock-up clutch 210 is disengaged to allow the engine 100 to rotate regardless of whether the automatic transmission 300 rotates or stops. During normal running, the pump impeller 220 and the turbine impeller 230 are connected by the lockup function of the lockup clutch 210 to prevent rotation loss.

  FIG. 2 shows a skeleton diagram of the automatic transmission 300, and FIG. 3 shows an operation table of the automatic transmission 300. According to the skeleton diagram shown in FIG. 2 and the operation table shown in FIG. 3, clutch elements (C (0) to C (2) in the figure) and brake elements (B (0) to B (4)) ), In which gear stage the one-way clutch elements (F (0) to F (2)) are engaged and released. At the first speed used when the vehicle starts, the clutch elements (C (0), C (1)), brake elements (B (4)), and one-way clutch elements (F (0), F (2)) are engaged. Match.

  Note that the ECT_ECU 400, which is a control device according to the present embodiment, changes the capacity coefficient C of the fluid coupling 200 by slip control of the lockup clutch 210 in order to give a desired acceleration time to the vehicle at the start, The motor generator 500 assists the engine 100 in order to satisfy an acceleration request that cannot be satisfied by such capacity coefficient control. For this reason, it is assumed that the lock-up clutch 210 is in a released state at the time of starting. This is consistent with the fact that the lock-up clutch 210 is in the released state because the engine is stalled when the lock-up clutch 210 is locked when the vehicle starts.

  Referring to FIG. 4, the capacity coefficient characteristic curve of capacity coefficient C of fluid coupling 200 with respect to speed ratio e in the high speed ratio region, stored in the internal memory of ECT_ECU 400 that is the control apparatus according to the present embodiment. explain. In the ECT_ECU 400 that realizes the control device according to the present embodiment, the lockup clutch engagement pressure of the lockup clutch 210 is controlled in order to make the capacity coefficient C of the fluid coupling 200 with the lockup clutch 210 variable. The slip-up clutch 210 is slip-controlled. Thereby, the engagement pressure of the lockup clutch 210 is variable, and the capacity coefficient C of the fluid coupling 200 is variable.

  As shown in FIG. 4, for the speed ratio e, the capacity coefficient C is different from the normal capacity coefficient characteristic curve (1) and capacity coefficient characteristics in the high speed ratio region. Two characteristics of curve (3) are further stored. In the present embodiment, two types of characteristic curves different from normal characteristic curves are further described. However, the present invention is not limited to this. Further, such a characteristic curve may be included in a map including the other characteristic curves described below, or may be included in a mathematical expression.

  As shown in FIG. 4, both the capacity coefficient characteristic curve (2) and the capacity coefficient characteristic curve (3) with respect to the normal capacity coefficient characteristic curve (1), even if the speed ratio e exceeds 0.5, the capacity coefficient C keeps the initial value as long as possible.

Here, the capacity coefficient C is expressed by C = T (P) / N (P) ² where T (P) is the transmission torque of the fluid coupling 200 and N (P) is the rotational speed of the pump impeller 220. It is. The speed ratio e is e = N (T) / N (P) where N (T) is the output shaft rotational speed of the fluid coupling 200 and N (P) is the input shaft rotational speed of the fluid coupling 200. Represented.

A relationship between output torque T (E) of engine 100 and input torque T (P) of fluid coupling 200 will be described. When the inertia of the engine 100 is I, the angular velocity is ω, and the angular acceleration is dω / dt, the relationship {T (E) −T (B)} = (I · dω / dt) is established. The angular velocity ω is {(2π / 60) · N (E)}, and the angular velocity ω and the engine speed N (E) (= N (P)) are in a one-to-one relationship. ) And {C · ω ² } are in a proportional relationship. From this, the magnitude of the capacity coefficient C corresponds to the magnitude of the input torque T (P) of the fluid coupling 200, in other words, for the same input torque T (P) when the capacity coefficient C is large. It can be seen that the input rotational speed N (P) becomes smaller.

  As described above, the torque represented by {T (E) −T (P)} is a torque used to increase the rotational speed of engine 100 by acting on engine inertia 110. That is, the torque that has not been transmitted to the connected drive wheels. When the gear ratio of “1st” shown in FIG. 3 is as large as 5.0 to 6.0, the time during which the capacity coefficient C is large in the region where the speed ratio e is large as shown in FIG. 4 is extended. Thus, the torque generated in the engine 100 is not used to increase the engine speed N (E) by acting on the engine inertia 110 but to transmit it to the connected drive wheels. become. As a result, the time during which a relatively large acceleration is generated in the vehicle can be extended immediately after the vehicle starts.

  That is, as shown in FIG. 4, in a region where the speed ratio e is large, the capacity coefficient C is usually decreased as the speed ratio e is larger. When the capacity coefficient C decreases, the torque generated in the engine 100 works on the engine inertia 110 rather than being transmitted to the connected drive wheels, thereby increasing the rotational speed N (E) of the engine 100. On the high speed ratio side, if a large value is maintained without decreasing the capacity coefficient as shown in FIG. 4, the torque generated in the engine 100 works on the engine inertia 110 and the engine speed N (E ) Is not used for raising, so that it is transmitted to the connected drive wheels. As a result, the time during which a relatively large acceleration is generated can be prolonged.

  As shown in FIG. 5, when the capacity coefficient C is the normal capacity coefficient characteristic curve (1), the engine speed increases (the torque generated in the engine 100 works against the engine inertia 110 and the engine Therefore, the torque generated in the engine 100 is not transmitted to the connected drive wheels, and the acceleration G peak does not continue. On the other hand, as shown in FIG. 4, in the region where the speed ratio e is large as in the capacity coefficient characteristic curve (2) or the capacity coefficient characteristic curve (3), the timing for decreasing the capacity coefficient C is delayed. The timing at which the number of revolutions rises is delayed. Accordingly, as shown in FIG. 5, the torque generated in the engine 100 does not work on the engine inertia 110 to increase the rotational speed of the engine 100, but the torque generated in the engine 100 is applied to the connected drive wheels. The peak of the acceleration G is sustained by being transmitted.

  With reference to FIG. 6, the relationship between the acceleration request degree and the lockup clutch slip amount will be described. The ECT_ECU 400 according to the present embodiment makes the capacity coefficient C of the fluid coupling 200 variable by controlling the engagement pressure of the lock-up clutch 210 and slip-controlling the lock-up clutch. As shown in FIG. 6, the greater the degree of acceleration request, the smaller the slip amount of the lock-up clutch 210 (without slipping), and the slip that transmits the torque generated in the engine 100 to the connected drive wheels as much as possible. Be controlled. Conversely, when the acceleration request degree is small, the slip amount of the lock-up clutch 210 is increased (slipped), and the torque generated in the engine 100 is applied to the engine inertia 110 to rotate the engine 100 itself. Slip control is performed so that the number N (E) increases.

  Referring to FIG. 7, the capacity coefficient characteristic curve of capacity coefficient C of fluid coupling 200 with respect to speed ratio e in the low speed ratio region, stored in the internal memory of ECT_ECU 400 serving as the control apparatus according to the present embodiment. explain.

  As shown in FIG. 7, for the speed ratio e, the capacity coefficient C is different from the normal capacity coefficient characteristic curve (1) and the capacity coefficient characteristics in the low speed ratio region. Two characteristic curves of the curve (3) are further stored. In the present embodiment, two types of characteristic curves different from normal characteristic curves are further described. However, the present invention is not limited to this.

  As shown in FIG. 7, both the capacity coefficient characteristic curve (2) and the capacity coefficient characteristic curve (3) with respect to the normal capacity coefficient characteristic curve (1) until the speed ratio e exceeds about 0.5. The rise of C is suppressed as much as possible. In the low speed ratio region, the smaller the capacity coefficient C, the faster the rotational speed of the engine 100 increases and the torque of the engine 100 itself increases. If the capacity coefficient C is kept from increasing in the low speed ratio region, the rotational speed of the engine 100 increases rapidly, the speed ratio e increases, and the capacity coefficient C begins to increase gradually. Torque is transmitted in this state. At that time, since the rotational speed is sufficiently increased (because the torque is large and the power is large), the peak value of acceleration can be increased.

  When the gear ratio of “1st” shown in FIG. 3 is relatively small such as 2.0 to 3.0, the capacity coefficient C is small in the region where the speed ratio e is small as shown in FIG. Thus, the torque generated in the engine 100 can be used for the engine inertia 110 to increase the engine speed N (E). As a result, the peak value of acceleration generated in the vehicle can be increased immediately after the vehicle starts.

  That is, as shown in FIG. 7, in a region where the speed ratio e is small, the capacity coefficient C is usually increased as the speed ratio e increases. When the capacity coefficient C increases, the torque generated in the engine 100 is transmitted to the connected drive wheels rather than acting on the engine inertia 110 to increase the rotational speed N (E) of the engine 100. On the low speed ratio side, if a small value is maintained without increasing the capacity coefficient as shown in FIG. 7, the torque generated in the engine 100 is not used for being transmitted to the connected driving wheels, It is used to increase the rotational speed N (E) of the engine 100 by acting on the inertia 110. Since torque is transmitted in a state where the rotational speed of engine 100 is sufficiently increased, the peak value of acceleration can be increased.

  As shown in FIG. 8, when the capacity coefficient C is the normal capacity coefficient characteristic curve (1), the engine speed does not increase (the torque generated in the engine 100 is transmitted to the connected drive wheels. Therefore, the rotational speed of the engine 100 does not increase), and the torque generated in the engine 100 is transmitted to the connected drive wheels. The peak value of acceleration G is small. On the other hand, as shown in FIG. 7, in the region where the speed ratio e is small as in the capacity coefficient characteristic curve (2) or the capacity coefficient characteristic curve (3), the timing for increasing the capacity coefficient C is delayed. The timing at which the number of revolutions increases increases. Accordingly, as shown in FIG. 8, the torque generated in the engine 100 is transmitted to the engine inertia 110 after increasing the rotation speed of the engine 100 by acting on the engine inertia 110. Therefore, the large power and torque generated in the engine 100 are transmitted. Is transmitted to the connected driving wheel, and the peak value of the acceleration G is increased.

  With reference to FIG. 9, the relationship between the acceleration request degree and the lockup clutch slip amount in the low speed ratio region will be described. The ECT_ECU 400 according to the present embodiment makes the capacity coefficient C of the fluid coupling 200 variable by controlling the engagement pressure of the lock-up clutch 210 and slip-controlling the lock-up clutch. As shown in FIG. 9, as the degree of acceleration request increases, the slip amount of the lockup clutch 210 is increased (slipped), and the torque N (E) of the engine 100 increases with the torque generated in the engine 100. So that it is slip controlled. Conversely, when the degree of acceleration request is small, slip control is performed so that the slip amount of the lockup clutch 210 is reduced (not slipped) and torque generated in the engine 100 is transmitted to the connected drive wheels. .

  With reference to FIG. 10, the relationship between the speed ratio and the torque assist amount stored in the internal memory of ECT_ECU 400 serving as the control device according to the present embodiment will be described. As shown in FIG. 10, the torque assist amount is a function of the speed ratio, and the torque assist amount varies depending on the gear ratio at the start. The torque assist amount when the gear ratio is the smallest is indicated by the characteristic curve (1), and the torque assist amount when the gear ratio is the largest is indicated by the characteristic curve (6). For the other characteristic curves, the gear ratio increases in the order of the characteristic curve (2), the characteristic curve (3), the characteristic curve (4), and the characteristic curve (5). The amount of torque assist varies depending on the gear ratio at the start.

  With reference to FIG. 11 and FIG. 12, the relationship between the 1st gear ratio and the torque assist amount stored in the internal memory of ECT_ECU 400 which is the control apparatus according to the present embodiment will be described. As shown in FIGS. 11 and 12, the torque assist amount varies depending on the gear ratio at the time of start. When the 1st gear ratio is set on the horizontal axis, the torque assist amount has a downward-sloping characteristic. Further, as shown in FIG. 11, the torque assist amount tends to decrease as the low speed side capacity coefficient decreases or as the driving force source torque (engine torque) increases. Further, as shown in FIG. 12, the torque assist amount with respect to the change in the high speed side capacity coefficient is influenced by the inertia of the engine and the motor. For this reason, when the inertia is relatively small, the torque assist amount decreases as the capacity coefficient on the high speed side increases. On the other hand, when the inertia is relatively large, the torque assist amount becomes large.

  Referring to FIG. 13, a control structure of a program executed by ECT_ECU 400 that is the control device according to the present embodiment will be described.

  In step (hereinafter step is abbreviated as S) 10, ECT_ECU 400 detects the vehicle speed. This detection is performed based on a vehicle speed detection signal input to the ECT_ECU 400.

  In S12, ECT_ECU 400 determines whether or not the detected vehicle speed is equal to or less than the start threshold value. The start threshold value is stored in advance in a memory built in the ECT_ECU 400. If the vehicle speed is less than or equal to the start threshold value (YES in S12), the process proceeds to S14. If not (NO in S12), the process proceeds to S38.

  In S14, ECT_ECU 400 detects the accelerator opening. This detection is performed based on an accelerator opening signal input to the ECT_ECU 400. In S16, ECT_ECU 400 determines whether or not the detected accelerator opening is equal to or greater than a predetermined opening threshold value. The opening degree threshold value is stored in advance in a memory built in the ECT_ECU 400. If the accelerator opening is larger than the opening threshold (YES in S16), the process proceeds to S18. If not (NO in S16), the process proceeds to S38.

  In S18, ECT_ECU 400 calculates the accelerator opening change rate. This calculation is performed by calculating a time change rate of the accelerator opening based on the detected accelerator opening and a clock signal generated by a clock included in the ECT_ECU 400.

  At S20, ECT_ECU 400 determines whether or not the calculated accelerator opening change rate is smaller than a predetermined opening change rate threshold value. If the accelerator opening change rate is equal to or less than a predetermined opening change rate threshold value (YES in S20), the process proceeds to S38. If not (NO in S20), the process proceeds to S22.

  At S22, ECT_ECU 400 identifies the start gear ratio. This start gear ratio is determined by the ECT_ECU 400 itself. At S24, ECT_ECU 400 moves the process according to the identified start gear ratio.

  In S26, ECT_ECU 400 selects torque assist characteristic (1) for start gear ratio control (characteristic curve (1) in FIG. 10) to control motor generator 500. At this time, ECT_ECU 400 outputs an instruction signal to generate an assist amount of torque to inverter 600 connected to motor generator 500. Thereafter, this process ends.

  At S28, ECT_ECU 400 controls motor generator 500 by selecting torque assist characteristic (2) for start gear ratio control (characteristic curve (2) in FIG. 10). At this time, ECT_ECU 400 outputs an instruction signal to generate an assist amount of torque to inverter 600 connected to motor generator 500. Thereafter, this process ends.

  At S30, ECT_ECU 400 controls motor generator 500 by selecting torque assist characteristic (3) for start gear ratio control (characteristic curve (3) in FIG. 10). At this time, ECT_ECU 400 outputs an instruction signal to generate an assist amount of torque to inverter 600 connected to motor generator 500. Thereafter, this process ends.

  At S32, ECT_ECU 400 controls motor generator 500 by selecting torque assist characteristic (4) for start gear ratio control (characteristic curve (4) in FIG. 10). At this time, ECT_ECU 400 outputs an instruction signal to generate an assist amount of torque to inverter 600 connected to motor generator 500. Thereafter, this process ends.

  In S34, ECT_ECU 400 controls motor generator 500 by selecting torque assist characteristic (5) for start gear ratio control (characteristic curve (5) in FIG. 10). At this time, ECT_ECU 400 outputs an instruction signal to generate an assist amount of torque to inverter 600 connected to motor generator 500. Thereafter, this process ends.

  At S36, ECT_ECU 400 controls motor generator 500 by selecting torque assist characteristic (6) for start gear ratio control (characteristic curve (6) in FIG. 10). At this time, ECT_ECU 400 outputs an instruction signal to generate an assist amount of torque to inverter 600 connected to motor generator 500. Thereafter, this process ends.

  In S38, ECT_ECU 400 sets that there is no torque assist processing by motor generator 500. Thereafter, this process ends.

  An operation of the power train according to the present embodiment based on the above-described structure and flowchart will be described.

  When the control is started, the vehicle speed is detected (S10). If the vehicle speed is equal to or less than the start threshold, it is determined that the vehicle is starting (YES in S12), and the accelerator opening is detected (S14). ). If the accelerator opening is equal to or greater than a predetermined opening threshold (YES in S16), the accelerator opening change rate is calculated (S18). If the accelerator opening change rate is larger than a predetermined opening change rate threshold value (YES in S20), the start gear ratio is detected (S22).

  When the start gear ratio identification number obtained from the start gear ratio is (1) (“1” in S24), the ECT_ECU 400 causes the torque assist characteristic (1) of the start gear ratio control (characteristic curve (1) in FIG. 10). Is selected and the motor generator 500 is controlled (S26).

  When the start gear ratio identification number obtained from the start gear ratio is (2) (“2” in S24), the ECT_ECU 400 causes the torque assist characteristic (2) of the start gear ratio control (characteristic curve (2) in FIG. 10). Is selected and the motor generator 500 is controlled (S28).

  When the start gear ratio identification number obtained from the start gear ratio is (3) (“3” in S24), the ECT_ECU 400 causes the torque assist characteristic (3) of the start gear ratio control (characteristic curve (3) in FIG. 10). Is selected and the motor generator 500 is controlled (S30).

  If the start gear ratio identification number obtained from the start gear ratio is (4) (“4” in S24), the ECT_ECU 400 causes the start gear ratio control torque assist characteristic (4) (characteristic curve (4) in FIG. 10). Is selected and the motor generator 500 is controlled (S32).

  When the start gear ratio identification number obtained from the start gear ratio is (5) (“5” in S24), the ECT_ECU 400 causes the torque assist characteristic (5) of the start gear ratio control (characteristic curve (5) in FIG. 10). Is selected and the motor generator 500 is controlled (S34).

  When the starting gear ratio identification number obtained from the starting gear ratio is (6) (“6” in S24), the ECT_ECU 400 causes the torque assist characteristic (6) of the starting gear ratio control (characteristic curve (6) in FIG. 10). Is selected and the motor generator 500 is controlled (S36).

  Thus, the torque assist amount is changed depending on the difference in the start gear ratio. By appropriately selecting the characteristic curves (1) to (6) in FIG. 10 based on the starting gear ratio with respect to the normal capacity coefficient characteristic curve (1) in FIG. 7, the difference in the starting gear is compensated. The same acceleration performance can be realized.

  As described above, according to the power train according to the present embodiment, the capacity coefficient of fluid coupling is changed in accordance with the speed ratio. At this time, the characteristics of the capacity coefficient are stored separately for the low speed ratio area and the high speed ratio area. The acceleration generated in the vehicle is determined according to the characteristics of these capacity coefficients. On the other hand, the torque assist characteristic of the motor that assists the engine with respect to the gear ratio at the time of start is defined. At this time, it is defined separately for each gear ratio at the time of start. The ECT_ECU causes the motor to assist the acceleration expressed by the capacity coefficient defined corresponding to the speed ratio, corresponding to the start gear ratio. At this time, the torque assist characteristics are divided according to the magnitude of the gear ratio. As a result, in a vehicle equipped with a fluid coupling with a lock-up clutch, it is possible to provide a vehicle powertrain that realizes sufficient acceleration performance regardless of the gear ratio at the time of start.

  Moreover, although the example which applied the control apparatus which concerns on this invention to the fluid coupling with a lockup clutch was demonstrated in embodiment mentioned above, the control apparatus of this invention is not limited to this. For example, instead of the fluid coupling with a lock-up clutch, the control device according to the present invention may be applied to a torque converter with a lock-up clutch. Even if a torque converter is used in place of the fluid coupling, a desired acceleration can be realized by compensating for the difference in the starting gear ratio by assisting the engine with torque by a motor.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the structure of the power train of the vehicle by which the control apparatus which concerns on embodiment of this invention is mounted. FIG. 2 is a skeleton diagram of the automatic transmission shown in FIG. 1. It is a figure showing the operation | movement engagement state of the automatic transmission shown in FIG. It is a figure which shows the relationship of the capacity | capacitance coefficient of fluid coupling with respect to the speed ratio in a low speed ratio area | region. It is a figure which shows the change of the acceleration with respect to time in a low speed ratio area | region. It is a figure which shows the relationship of the slip amount of the lockup clutch of a fluid coupling with respect to the acceleration request | requirement degree. It is a figure which shows the relationship of the capacity | capacitance coefficient of fluid coupling with respect to the speed ratio in a low speed ratio area | region. It is a figure which shows the change of the acceleration with respect to time in a high speed ratio area | region. It is a figure which shows the relationship of the slip amount of the lockup clutch of a fluid coupling with respect to the acceleration requirement degree in a high speed ratio area | region. It is a figure which shows the torque assist characteristic curve with respect to speed ratio memorize | stored in the control apparatus which concerns on embodiment of this invention. It is a figure which shows the torque assist characteristic curve (the 1) with respect to 1st gear ratio memorize | stored in the control apparatus which concerns on embodiment of this invention. It is a figure which shows the torque assist characteristic curve (the 2) with respect to 1st gear ratio memorize | stored in the control apparatus which concerns on embodiment of this invention. It is a flowchart which shows the control structure of the process performed by ECT_ECU which concerns on embodiment of this invention.

Explanation of symbols

  100 engine, 110 engine inertia, 200 fluid coupling, 210 lock-up clutch, 220 pump impeller, 230 turbine impeller, 300 automatic transmission, 400 ECT_ECU, 500 motor generator, 600 inverter.

Claims (26)

A vehicle control device including a first power source, a second power source that assists the first power source, and a transmission that transmits a driving force from the power source through a fluid coupling. There,
The degree of assist of the driving force by the second power source is set so as to increase as the gear ratio of the transmission at the time of starting the vehicle decreases and according to the capacity coefficient of the fluid coupling. A control device including setting means. A vehicle control device including a first power source, a second power source that assists the first power source, and a transmission that transmits a driving force from the power source through a fluid coupling. There,
Calculating means for calculating the degree of acceleration required for the vehicle;
In accordance with the capacity coefficient of the fluid coupling, the larger the degree of acceleration calculated by the calculating means, the larger the gear ratio of the transmission when the vehicle starts, and the larger the gear ratio of the fluid coupling. And a setting unit for setting the degree of assist of the driving force by the second power source.   The calculating means includes means for calculating a ratio satisfied by the actual acceleration with respect to the required acceleration required for the vehicle and a degree of acceleration representing any difference between the required acceleration and the actual acceleration. The control device according to claim 2.   The control device according to claim 1, wherein the setting unit includes a unit for setting a plurality of change characteristics having different degrees of assistance corresponding to the gear ratio. The setting means includes
Means for setting a plurality of change characteristics having different degrees of assist corresponding to the gear ratio;
Means for setting the degree of assist of the driving force by the second power source by selecting one change characteristic from among the plurality of change characteristics. The control device described. The first power source is an engine, and the second power source is an electric motor;
The control device according to claim 1, wherein the setting unit includes a unit for setting a torque amount generated by the electric motor.   7. The control device according to claim 1, further comprising a determination unit configured to determine whether or not the setting unit sets a degree of assist of the driving force by the second power source. Control device. The control device further includes detection means for detecting a vehicle speed of the vehicle,
The determination means includes means for determining whether or not to set the degree of assist of the driving force by the second power source based on the vehicle speed detected by the detection means. Control device.   The determining means sets the degree of assist of the driving force by the second power source by the setting means when the vehicle speed is low, and the driving by the second power source by the setting means when the vehicle speed is high. The control device according to claim 8, comprising means for determining to cancel the setting of the force assist level.   The setting means increases the capacity ratio, speed ratio, the first power source and the second power source of the fluid coupling so that the gear ratio of the transmission when the vehicle starts is smaller. The control device according to claim 1, further comprising means for setting a degree of assist of the driving force by the second power source in accordance with inertia of the second power source.   The setting means increases as the degree of acceleration calculated by the calculation means increases, and increases as the gear ratio of the transmission when the vehicle starts to decrease, and the capacity of the fluid coupling. The apparatus according to claim 2, further comprising means for setting a degree of assist of the driving force by the second power source according to a coefficient, a speed ratio, and inertia of the first power source and the second power source. The control device described.   When the speed ratio of the fluid coupling is low, the setting means increases the amount of increase in the degree of assist of the driving force with respect to the amount of increase in the capacity coefficient of the fluid coupling. The control device according to claim 10 or 11, comprising means for setting the degree of assist of the driving force by the power source.   When the inertia of the first power source and the second power source is large, the setting means has an increase amount of the degree of assist of the driving force with respect to the increase amount of the capacity coefficient of the fluid coupling. The control device according to claim 10 or 11, further comprising means for setting a degree of assist of the driving force by the second power source so as to increase. A control method for a vehicle equipped with a first power source, a second power source that assists the first power source, and a transmission to which driving force from the power source is transmitted through a fluid coupling. There,
A setting step of setting the degree of assist of the driving force by the second power source so that the gear ratio of the transmission when the vehicle starts is smaller and the capacity coefficient of the fluid coupling is larger. Including a control method. A control method for a vehicle equipped with a first power source, a second power source that assists the first power source, and a transmission to which driving force from the power source is transmitted through a fluid coupling. There,
A calculation step for calculating a degree of acceleration required for the vehicle;
The larger the degree of acceleration calculated in the calculating step, the higher the degree, and the smaller the gear ratio of the transmission when starting the vehicle, the larger the degree of acceleration, and according to the capacity coefficient of the fluid coupling. And a setting step for setting the degree of assist of the driving force by the second power source.   The calculating step includes a step of calculating a ratio satisfied by an actual acceleration with respect to a required acceleration required for the vehicle and a degree of acceleration representing any difference between the required acceleration and the actual acceleration. Item 16. The control method according to Item 15.   The control method according to any one of claims 14 to 16, wherein the setting step includes a step of setting a plurality of change characteristics having different degrees of assistance corresponding to the gear ratio. The setting step includes
Setting a plurality of change characteristics with different degrees of assist corresponding to the gear ratio;
The step of setting the degree of assist of the driving force by the second power source by selecting one change characteristic from among the plurality of change characteristics is included. Control method. The first power source is an engine, and the second power source is an electric motor;
The control method according to any one of claims 14 to 18, wherein the setting step includes a step of setting a torque amount generated by the electric motor.   The control according to any one of claims 14 to 19, wherein the control method further includes a determination step of determining whether or not to set a degree of assist of the driving force by the second power source in the setting step. Method. The control method further includes a detection step of detecting a vehicle speed of the vehicle,
21. The step according to claim 20, wherein the determination step includes a step of determining whether or not to set the degree of assist of the driving force by the second power source based on the vehicle speed detected in the detection step. Control method.   When the vehicle speed is high, the determination step sets the second power source in the setting step so that the setting step sets the degree of assist of the driving force by the second power source when the vehicle speed is low. The control method according to claim 21, further comprising a step of determining to cancel the setting of the degree of assist of the driving force by.   The setting step is such that the smaller the gear ratio of the transmission when the vehicle starts, the larger the capacity coefficient of the fluid coupling, the speed ratio, the first power source, and the second power source. The control method according to claim 14, further comprising a step of setting a degree of assist of the driving force by the second power source in accordance with inertia of the second power source.   In the setting step, the larger the degree of acceleration calculated by the calculating means, the larger the gear ratio of the transmission when the vehicle starts, and the larger the capacity of the fluid coupling. The method according to claim 15, further comprising: setting a degree of assist of the driving force by the second power source according to a coefficient, a speed ratio, and inertia of the first power source and the second power source. Control method.   In the setting step, when the speed ratio of the fluid coupling is low, the amount of increase in the degree of assist of the driving force with respect to the amount of increase in the capacity coefficient of the fluid coupling is increased as compared with the case where the fluid coupling is high. The control method according to claim 23, comprising a step of setting a degree of assist of the driving force by the power source.   When the inertia of the first power source and the second power source is large, the setting means has an increase amount of the degree of assist of the driving force with respect to the increase amount of the capacity coefficient of the fluid coupling. The control method according to claim 23, comprising a step of setting a degree of assist of driving force by the second power source so as to increase.

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