JP2007198357A - Vehicle driving force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the generation of a driving force difference at finishing a speed change even if a driver operates an output amount operating member for a vehicle power source during the speed change. <P>SOLUTION: An ECU implements a program which includes a step (S400) of detecting an accelerator pedal opening (S200) when manual down-shift proceeds in off-acceleration (YES in S100) and calculating current turbine torque TT when the accelerator pedal opening is a threshold or greater (YES in S300), a step (S500) of calculating a shifting degree α, a step (S600) of estimating a current driving force F(NOW) on the basis of TT and α, a step (S700) of setting a target driving force F(TGT) as F(NOW), and a step (S800) of executing driving force control on the basis of F(TGT). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for a vehicle equipped with a stepped automatic transmission, and more particularly to a control device for avoiding a shock when a driver steps on an accelerator pedal during a shift in driving force request type control.

  In a power train having an engine mounted on a vehicle and an automatic transmission (a torque converter and a transmission mechanism (for example, a gear-type transmission mechanism)), the friction engagement element of the transmission mechanism is in a slipping state during a shift. The engine driving force is temporarily not transmitted to the driving wheels. Such a state in which no power is transmitted cannot be clearly recognized by the driver. Even if a driver who has an intention to accelerate depresses the accelerator pedal, if the timing of depressing the accelerator pedal is shifting, the driving force of the engine is not transmitted to the drive wheels. For this reason, the driver feels that the intention to accelerate is not reflected (for example, the play (play) of the accelerator pedal), and further depresses the accelerator pedal. As described above, when the opening degree of the accelerator pedal is changed during the shift, good shift characteristics cannot be realized.

  Japanese Patent Laid-Open No. 2003-343302 discloses an engine and automatic transmission control device that can achieve stable throttle control even when the accelerator pedal opening is changed by a driver during gear shifting. The control device includes a shift state detection unit that detects a shift state of the automatic transmission, and a storage unit that stores a throttle opening detected at the start of the shift, and the control unit detects that the shift is being performed. When the detected accelerator pedal opening is larger than the throttle opening at the start of shifting stored in the storage means, the engine is controlled so that the electronically controlled throttle is set to the throttle opening at the start of shifting.

According to this control device, even when the driver depresses the accelerator pedal during the shift, the throttle opening at the start of the shift is maintained. For this reason, since a large shock at the end of the shift is avoided and the throttle opening gradually corresponds to the accelerator pedal opening after the end of the shift, stable engine torque control can be achieved. It is possible to prevent the extension.
JP 2003-343302 A

  By the way, in a vehicle having an engine and an automatic transmission capable of controlling the engine output torque independently of the driver's accelerator pedal operation, based on the driver's accelerator pedal operation amount, vehicle driving conditions, etc. There is a concept of “driving force control” that realizes the calculated positive and negative target drive torque by the engine torque and the transmission gear ratio of the automatic transmission. In addition, control methods called “driving force request type”, “driving force demand type”, “torque demand method”, and the like are similar to this. In such driving force control, the target driving force is calculated based on the opening degree of the accelerator pedal operated by the driver, and the throttle opening degree of the engine is controlled.

  However, in Patent Document 1 described above, even if the accelerator pedal is depressed, the throttle opening is fixed to the throttle opening at the start of shifting without depending on the accelerator pedal opening. There is a possibility that a driving force step will occur at the end of the shift. In particular, a driver who has an intention to accelerate depresses the accelerator pedal during shifting, but since the friction engagement element is not engaged, the driving force is not transmitted to the drive wheels, and therefore the intention to accelerate is not reflected. Even when the pedal is stepped on, if the throttle opening is maintained at the throttle opening at the start of the shift, a larger driving force step at the end of the shift may occur. On the other hand, in Patent Document 1, when it is determined that the shift has been completed, if a deviation from the driver's required driving force occurs after the shift is completed as a result of fixing the throttle opening during the shift, all at once. It is merely disclosed that the throttle opening is not restored but is gradually restored, for example, via a temporary delay filter or the like (paragraph 0028 of Patent Document 1). Such a process not only eliminates the possibility of a large driving force step at the end of the shift, but also causes a delay time, so the driver's acceleration request (more driving force increases) (Request) cannot be met promptly.

  The present invention has been made to solve the above-described problems, and the object thereof is to provide a case where a member that operates an output amount of a power source of a vehicle is operated by a driver during gear shifting. It is an object of the present invention to provide a vehicle driving force control device that does not generate a driving force step at the end of shifting.

  According to a first aspect of the present invention, a vehicle driving force control apparatus controls a driving force of a vehicle including a power source and an automatic transmission. The control device controls at least a power source of the vehicle based on the setting means for setting a target driving force generated by the vehicle based on at least an operation amount of a member operated by the driver, and the target driving force. Control means, detection means for detecting that the automatic transmission is shifting, and calculation means for calculating the actual driving force actually generated in the vehicle. The setting means includes means for setting the actual driving force as the target driving force when it is detected that the automatic transmission is shifting.

  According to the first aspect of the invention, when such driving force control is executed, for example, a driver having an intention to accelerate starts a downshift by outputting a downshift command in the manual mode. Further, during the shift, the driver depresses the accelerator pedal as the operation member to try to realize the intention to accelerate. However, during the shift, the frictional engagement element of the automatic transmission is not completely engaged, so that no driving force is transmitted from the power source to the driving wheels. On the other hand, when the shift is completed, the friction engagement elements are completely engaged, and the driving force is transmitted from the power source to the driving wheels. The actual driving force is set as the target driving force during the shift including the end of the shift. By doing so, it is possible to avoid generating a large driving force corresponding to a large accelerator opening at the moment when the driving force is completely transmitted at the end of the shift. As a result, even when an operation for increasing the output is performed during the shift, it is possible to prevent a driving force step at the end of the shift from occurring.

  In the vehicle driving force control apparatus according to the second invention, in addition to the configuration of the first invention, the calculating means calculates the actual driving force based on the progress of the shift of the automatic transmission. including.

  According to the second invention, when the shift of the automatic transmission proceeds (especially the inertia phase), the driving force from the power source starts to be transmitted. The degree of progress of the shift can be calculated by, for example, a change in the turbine speed of the torque converter, and the actual driving force during the shift can be calculated based on the degree of progress.

  In the vehicle driving force control apparatus according to the third invention, in addition to the configuration of the first invention, the automatic transmission includes a torque converter, and the calculation means is based on turbine torque which is output torque from the torque converter. And means for calculating the actual driving force.

  According to the third invention, when the shift of the automatic transmission proceeds (especially the inertia phase), the driving force from the power source starts to be transmitted. The actual driving force during the shift can be calculated from the turbine torque of the torque converter, and the actual driving force during the shifting can be calculated based on the turbine torque.

  In the vehicle driving force control apparatus according to the fourth aspect of the invention, in addition to the configuration of any one of the first to third aspects, the setting means changes the speed when the actual driving force is set as the target driving force. When the medium is no longer detected, a means for gradually setting the target driving force based on the operation amount of the member is included.

  According to the fourth aspect of the invention, after the end of shifting, the target driving force is set by gradually changing the target driving force based on the operation amount of the member. For this reason, a driving force is generated corresponding to the accelerator pedal opening without causing a delay time as in the prior art. As a result, it is possible to realize a driving force in line with the driver's intention to accelerate.

  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.

  FIG. 1 illustrates a power train of a vehicle including an ECU that is a driving force control apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the vehicle includes an engine 100, a torque converter 200, a gear transmission mechanism 300, an ECU (Electronic Control Unit) 400 that controls these, and a manual that outputs a shift command signal to the ECU 400. It includes a mode-equipped shifting operation unit 500 and an accelerator pedal opening sensor 600 that inputs a signal representing the opening of the accelerator pedal to ECU 400.

  In the following description, the shift control applied to the power train having the engine 100, the torque converter 200, and the gear-type transmission mechanism 300 as shown in FIG. 1 will be described, but the present invention is not limited to this. is not. A power train including a motor, a motor generator, or the like may be used instead of the power train including the engine 100, the torque converter 200, and the gear-type transmission mechanism 300. In this case, the required driving force is a driving force generated by being assisted by a motor or a motor generator in addition to the engine, or a driving force generated by the motor or the motor generator when the engine is stopped.

  ECU 400 outputs a control signal such as a throttle opening command signal to engine 100 and receives a detection signal such as an engine speed signal. ECU 400 also outputs a control signal that commands engagement or disengagement (including slip) of the lock-up clutch of torque converter 200. The ECU 400 also outputs a control signal, which is a hydraulic pressure command signal for engaging and releasing the friction engagement element to the gear transmission mechanism 300, and the turbine speed from the gear transmission mechanism 300. Detection signals such as NT and output shaft rotational speed NOUT are input.

  The shift operation unit 500 with a manual mode receives a shift position of an automatic transmission operated by a driver or an upshift command or a downshift command of a shift gear stage in the manual mode. For example, the shift positions include P (parking), R (reverse travel), N (neutral), and D (forward travel).

  In the D position, when a predetermined shift diagram (upshift shift line and downshift shift line) is crossed from the vehicle speed and the throttle opening, the current shift gear stage is upshifted and the shift gear stage is 1 The gear shifts up to the high-speed gear, or downshifted, and the gear shifts down to the low-speed gear.

  Furthermore, it has a manual mode position (M position). At the M position, a shift command signal that causes a downshift by one step when the shift lever is tilted to the-side, and a shift lever is tilted to the + side. A shift command signal for upshifting by one stage is input to ECU 400.

  The accelerator pedal opening sensor 600 detects the opening of the accelerator pedal operated by the driver. The detected accelerator pedal opening is input to ECU 400.

  ECU 400, which is the driving force control apparatus according to the present embodiment, receives a downshift command signal in the manual mode, and the driver depresses the accelerator pedal more than a predetermined opening degree with an intention to accelerate during shifting. Even in this case, the driving force of engine 100 is controlled so as not to generate a driving force step at the end of shifting. Hereinafter, such control will be described in detail with reference to flowcharts.

  With reference to FIG. 2, a control structure of a program executed by ECU 400 that is the control device according to the present embodiment will be described.

  In step (hereinafter step is abbreviated as S) 100, ECU 400 determines whether or not a manual downshift is being performed with the accelerator off. This determination is based on a shift command signal input to the ECU 400 from the shift operation unit 500 with the manual mode, an accelerator pedal opening input from the accelerator pedal opening sensor 600, and a shift control signal output from the ECU 400 to the gear-type transmission mechanism 300. Etc. If manual downshift is being performed with the accelerator off (YES in S100), the process proceeds to S200. Otherwise (NO in S100), this process ends.

  In S200, ECU 400 detects the opening of the accelerator pedal. At this time, ECU 400 detects the opening of the accelerator pedal based on the signal input from accelerator pedal opening sensor 600.

  In S300, ECU 400 determines whether or not the accelerator pedal opening is equal to or greater than a threshold value. This threshold value is a constant or a value determined by a map or the like, and is set to a value that may cause a driving force step at least at the end of shifting. If the accelerator pedal opening is equal to or greater than the threshold value (YES in S300), the process proceeds to S400. Otherwise (NO in S300), this process ends.

  In S400, ECU 400 calculates currently generated turbine torque TT. The turbine torque TT is calculated by calculating the engine torque TE from a map using the engine speed NE or the like as a parameter, and considering the engine torque TE in consideration of the characteristics of the torque converter 200 (multiplying the torque ratio). . However, such a calculation method is an example, and the turbine torque TT may be calculated by another method.

  In S500, ECU 400 calculates shift progression degree α. This shift progression degree α is calculated by, for example, α = (NT−NOGEAR) / (NT−NOGEAR at the start of shift), where NT is the turbine rotation speed and NOGEAR is the synchronous rotation speed after the shift. Note that the turbine rotational speed NT changes after starting the inertia phase after the end of the torque phase during the shift (which gradually increases from the NT at the start of the shift to the current NT), and the shift progress rate α is 1. Calculated as a value between ˜0. As the inertia phase proceeds, a downshift is assumed, and the current turbine speed NT increases, so the shift progress rate α decreases from 1 to 0. However, such a calculation method is an example, and the shift progress degree α may be calculated by another method.

  In S600, ECU 400 estimates currently generated driving force F (NOW) based on turbine torque TT and shift progress rate α. For example, by multiplying the turbine torque TT by (1-shift progress degree α), or by correcting such calculation results or during calculation, the currently generated drive torque is calculated and divided by the tire radius. The driving force F (NOW) is estimated. However, such a calculation method is an example, and the currently generated driving force F (NOW) may be estimated by another method.

  In S700, ECU 400 sets target drive force F (TGT) to generated drive force F (NOW). In this manner, during the shift, the target driving force F (TGT) becomes the actually generated driving force estimated using the shift progress degree α as a parameter, and the target driving force F (TGT) after the shift is completed. Is the generated driving force F (NOW) immediately before the end of shifting.

  In S800, ECU 400 executes the driving force control of engine 100, for example, by controlling the throttle opening so that an engine torque corresponding to target driving force F (NOW) is generated.

  The operation of ECU 400 serving as the control device according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIG. Note that this program is repeatedly executed at a predetermined cycle time.

  FIG. 3A shows the time change of the accelerator pedal opening, and FIG. 3B shows the time change of the driving force. It is assumed that the manual downshift is started at time T (1) and the shift is completed at time T (4). It is assumed that the driver depresses the accelerator pedal at time T (2) during the shift, but does not accelerate, so that the driver further depresses the accelerator pedal at time T (3). The driver's operation at this time T (3) does not generate the desired driving force and the vehicle does not accelerate. Therefore, the amount of the accelerator pedal that was stepped on from time T (2) to time T (3) It is thought that there is a cause in judging that it corresponds to play. The driving force as intended is not generated because the driving force of the engine 100 is not transmitted to the driving wheels during the shift because the frictional engagement element of the gear-type transmission mechanism is not completely engaged. It is.

  When the driver does not step on the accelerator pedal and tries to accelerate the vehicle (for example), in the shift operation unit with manual mode 500 shown in FIG. 1, the shift lever is tilted to the-side of the M position (manual position) ( A downshift is started (this is time T (1)). At time T (2) during shifting, the driver depresses the accelerator pedal to accelerate the vehicle, and the intention to accelerate cannot be realized. Therefore, when the accelerator pedal is further depressed at time T (3), the accelerator pedal is further increased. The opening degree is equal to or greater than the threshold value (YES in S300).

  The currently generated turbine torque TT is calculated (S400), the shift progress rate α is calculated (S500), and the currently generated driving force F (NOW) is estimated based on the currently generated turbine torque TT and the shift progress rate α (S600). ). The target driving force F (TGT) is set to the currently generated driving force F (NOW) (S700). Engine 100 is controlled to achieve this target driving force F (TGT) (S800).

  In FIG. 3B, the time change of the driving force according to the prior art is indicated by a dotted line, and the time change of the driving force according to the present invention is indicated by a solid line. In the prior art, the frictional engagement element is completely engaged simultaneously with the end of the shift, and the driving force corresponding to the accelerator pedal opening increased at time T (3) is output from the engine 100. Therefore, a large driving force is generated at time T (4), and the driver obtains an acceleration feeling far greater than the intended acceleration intention as shown by the dotted line in FIG. (4) After that, the accelerator pedal is made constant or returned.

  On the other hand, in the present invention, the currently generated driving force F (NOW) using the turbine torque TT and the shift progress degree α is set as the target driving force F (TGT) during the shifting. For this reason, even at the end of the shift (time T (4)), the generated driving force F (NOW) generated immediately before is set as the target driving force F (TGT). Therefore, the generation of excessive driving force can be suppressed, and driving force control having a strong correlation with the accelerator pedal opening can be realized as shown by the solid line in FIG. Therefore, unlike the conventional case, since the driving force corresponding to the intention to accelerate is not generated, the driver does not perform the operation of returning the accelerator pedal.

  In this way, in response to the driver's intention to accelerate indicated by the two-dot chain line in FIG. 3 (A), the driver indicates the accelerator pedal opening by the solid line in FIG. 3 (A) until time T (4). To change. In the prior art, if a desired acceleration feeling cannot be obtained during a shift, a large driving force corresponding to the increased accelerator pedal opening is output from the engine 100 after the shift is completed, and the friction engagement element is also engaged in other words. Therefore, a remarkably large driving force is generated (dotted line in FIG. 3B), and the driver returns the accelerator pedal (dotted line after T (4) in FIG. 3A). In the present invention, the target driving force F (TGT) after the completion of the shift is the immediately preceding generated driving force F (NOW), so that a desired acceleration feeling can be obtained in a state where the friction engagement elements are completely engaged. It is done. For this reason, once the desired acceleration feeling is not obtained during shifting, the increased accelerator pedal is not returned, and a driving force corresponding to the driver's accelerator pedal opening is generated (see FIG. 3A). A solid line after T (4) and a solid line after T (4) in FIG. 3B). At this time, it is preferable to control the target driving force F (TGT) so as to gradually change so as not to generate a large shock. More preferably, at this time, the target driving force F (TGT) is controlled to gradually change in correspondence with the accelerator pedal opening so that the driver's intention to accelerate without realizing a large shock is realized. Is preferred.

  As described above, according to the ECU that is the driving force control apparatus according to the present embodiment, even when the accelerator pedal is operated during the shift, after the shift is completed in which the friction engagement element is completely engaged. It is possible to avoid the generation of a driving force step.

  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 control block diagram containing ECU which is a control device of vehicles concerning this embodiment. It is a flowchart which shows the control structure of the program performed by ECU. It is a timing chart which shows the time change of an accelerator pedal opening and a driving force.

Explanation of symbols

  100 engine, 200 torque converter, 300 gear-type speed change mechanism, 400 ECU, 500 speed change operation unit with manual mode, 600 accelerator pedal opening sensor.

Claims (4)

A driving force control device for a vehicle including a power source and an automatic transmission,
A setting means for setting a target driving force generated by the vehicle based on at least an operation amount of a member operated by a driver;
Control means for controlling at least a power source of the vehicle based on the target driving force;
Detecting means for detecting that the automatic transmission is shifting;
Calculating means for calculating the actual driving force actually generated in the vehicle,
The setting means includes a means for setting the actual driving force as the target driving force when it is detected that the automatic transmission is shifting.   The vehicle driving force control apparatus according to claim 1, wherein the calculating means includes means for calculating the actual driving force based on a progress degree of shifting of the automatic transmission. The automatic transmission includes a torque converter;
The vehicle driving force control apparatus according to claim 1, wherein the calculating means includes means for calculating the actual driving force based on a turbine torque that is an output torque from the torque converter.   When the actual driving force is set as the target driving force, the setting means gradually changes the target driving force based on the amount of operation of the member when it is no longer detected that shifting is being performed. The vehicle driving force control device according to any one of claims 1 to 3, further comprising means for setting the

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