Vehicle control system

Abstract

The present invention provides a vehicle control device that can suppress the occurrence of rattling while quickly increasing the input torque from the drive source near the end of the gradual torque increase section. [Solution] In the electronic control device 30 of the electric vehicle 12, the timing control unit 38 controls the rise timing of the input torque Ti from the electric motor (drive source) 10 from the torque rise gradual change control unit 34, based on the sign direction of the waveform of the differential torque ΔT calculated by the differential torque calculation unit 36 ​​at the start of pulsation near the end of the torque rise gradual change control section Tf. This allows the input torque Ti from the electric motor 10 to rise quickly while suppressing the occurrence of rattling shock S.

Description

Technical Field

[0001] The present invention relates to a vehicle control device that alleviates an increase in driving torque in order to reduce rattling noise and shock in a drive system when switching from a non-driving state to a driving state of a vehicle.

Background Art

[0002] In Patent Document 1, driving torque from an internal combustion engine is transmitted via a gear-type power transmission device such as a transmission, and while detecting the output-side rotational speed in the gear-type power transmission device during the transition process from a decelerating state to an accelerating state of the vehicle, a torque increase slow change control section is provided to alleviate an increase in input torque from the internal combustion engine in order to suppress a backlash jamming shock that occurs when the backlash of the gears jams. When the rotational speed increases by a predetermined amount, the vehicle control device that cancels the driving torque increase slow change control is disclosed. Thereby, it is possible to end the driving torque increase slow change control at an appropriate timing, appropriately suppress the occurrence of gear rattling shock, and improve the responsiveness to an acceleration request.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the vehicle control device described in Patent Document 1, the moment when the backlash of the gears jams is determined from an increase in the output-side rotational speed in the gear train. Since the change in rotational speed appears as an integral value with respect to the torque amount, there is a delay until the actual rattling shock appears in the change in rotational speed, so sufficient responsiveness could not be obtained.

[0005] The present invention was made against the above circumstances, and its objective is to provide a vehicle control device that can quickly increase the input torque from the drive source near the end of the slow torque increase section while suppressing the occurrence of rattling.

[0006] Based on the circumstances described above, the inventors conducted various studies and found that when the difference torque (= output torque - input torque) between the input torque from a drive source such as an engine or electric motor and the output torque of a gear-type power transmission device is converted onto a common axis and calculated, the difference torque pulsation starts with a downward convex waveform if there is no play near the end of the torque increase gradual change control section, or if the input torque rises earlier than the play occurs. On the other hand, if the timing of the play near the end of the torque increase gradual change control section coincides with the rise of the input torque, the difference torque pulsation starts with an upward convex waveform. The present invention is based on this finding. [Means for solving the problem]

[0007] In other words, the gist of the first invention is a vehicle control device that includes (a) a gear-type power transmission device in the power transmission path between a drive source and a drive wheel, and performs torque rise gradual change control to gradually change the increase in input torque from the drive source when switching from a non-driving state to a driving state, and (b) a differential torque calculation unit that calculates the difference torque between the input torque from the drive source and the output torque of the gear-type power transmission device by converting it onto a common shaft, and (c) a timing control unit that controls the rising timing of the input torque from the drive source from the torque rise gradual change control based on the sign direction of the waveform at the start of pulsation of the differential torque from the end of the torque rise gradual change control.

[0008] The gist of the second invention is that, in the first invention, when the differential torque is defined as "output torque - input torque", the timing control unit delays the rise time of the input torque from the drive source by a certain amount if the waveform at the start of pulsation of the differential torque is in the negative direction, advances the rise time of the input torque from the drive source by a certain amount if the waveform at the start of pulsation of the differential torque is in the positive direction, and does not change the rise time of the input torque from the drive source if the waveform at the start of pulsation of the differential torque changes from the negative direction to the positive direction. [Effects of the Invention]

[0009] According to the vehicle control device of the first invention, the timing control unit controls the rise timing of the input torque from the drive source from the torque rise gradual change control, based on the sign direction of the waveform of the differential torque calculated by the differential torque calculation unit at the start of pulsation from the end of the torque rise gradual change control. This makes it possible to quickly rise the input torque from the drive source while suppressing the occurrence of rattling.

[0010] According to the vehicle control device of the second invention, the timing control unit delays the rise time of the input torque from the drive source by a certain amount if the waveform at the start of differential torque pulsation is in the negative direction, advances the rise time of the input torque from the drive source by a certain amount if the waveform at the start of differential torque pulsation is in the positive direction, and does not change the rise time of the input torque from the drive source if the waveform at the start of differential torque pulsation changes from the negative direction to the positive direction. As a result, the input torque from the drive source can be quickly brought up while suppressing the occurrence of rattling. [Brief explanation of the drawing]

[0011] [Figure 1] This figure schematically illustrates the vehicle drive system of the present invention and illustrates the main components of the electronic control device provided in the vehicle drive system. [Figure 2]This is a time chart that schematically explains the phenomenon of change in output torque, including the change in input torque accompanying the change in accelerator opening, and the change in output torque due to rattling that occurs near the end of the torque increase gradual change control section, in the drive system of the vehicle shown in Figure 1. [Figure 3] Figure 1 is a time chart showing the torque change in a vehicle where no rattling occurs near the end of the torque increase gradual change control. The changes in input torque and output torque are shown in the upper section, and the changes in differential torque are shown in the lower section. [Figure 4] Figure 3 is a simulation diagram showing the waveforms when the input torque is increased at multiple rise timings relative to the rattle timing. The changes in input torque and output torque are shown in the upper panel, and the changes in differential torque are shown in the lower panel. [Figure 5] Figure 1 is a flowchart illustrating the key aspects of the control operation of the electronic control unit installed in the vehicle. [Modes for carrying out the invention]

[0012] The vehicle's power transmission system is a device that transmits power from the drive source to the drive wheels. The drive source is, for example, an electric motor in an electric vehicle, or an engine in an engine-powered vehicle. Between the drive source and the drive wheels, there is a transmission or differential gear system, and backlash exists due to the gap (play) between the tooth surfaces based on the meshing gear or spline fitting structure. When power transmission is interrupted between a non-driven state and a driven state and then resumed, the tooth surfaces collide due to the reduction of backlash, causing what is known as rattling (shock).

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings have been simplified or modified as appropriate, and the dimensional ratios and shapes of each part are not necessarily accurately depicted. [Examples]

[0014] Figure 1 is a schematic diagram illustrating the configuration of a power transmission device 14 of an electric vehicle 12 equipped with an electric motor 10 as a drive source. In Figure 1, the power transmission device 14 is configured as a gear-type power transmission device, with an input shaft 16 to which power from the electric motor 10 is input, and a reduction gear 22 that reduces the rotation of the input shaft 16 and transmits it to the drive wheels 20 via an output shaft 18. The reduction gear 22 is representative of a transmission or differential gear system. The output shaft 18 is representative of a power transmission shaft within a transmission or between a transmission and a differential gear system, or a drive shaft between a differential gear system and the drive wheels 20. Equivalently, the output shaft 18 is equipped with a spring element 24 having a spring constant K and a capacitive element 26 having a capacity coefficient C, arranged in parallel.

[0015] The power transmission device 14 is equipped with an electronic control device 30 that quickly raises the output torque To while mitigating the rattling shock S when switching from a non-driven state to a driven state. The electronic control device 30 is supplied with signals representing the input torque Ti and output torque To from torque sensors provided on the input shaft 16 and output shaft 18, respectively. The torque sensors acquire signals corresponding to the torque from strain cages attached to the input shaft 16 and output shaft 18, for example, via a rotary transformer or the like. The input torque Ti may be calculated based on the drive current value of the electric motor 10. The electronic control device 30 is also supplied with a signal representing the accelerator opening θacc from a well-known accelerator opening sensor.

[0016] The electronic control unit 30 is composed of a so-called microcomputer that functions as a control device for the electric vehicle 12, and functionally includes a drive control unit 32, a torque increase gradual change control unit 34, a differential torque calculation unit 36, and a timing control unit 38.

[0017] As shown in Figure 2, the drive control unit 32 basically controls the driving force of the electric vehicle 12 by increasing the input torque Ti input from the electric motor 10 to the input shaft 16 in accordance with the increase in the accelerator opening θacc.

[0018] The torque increase slow change control unit 34 suppresses the increase in the input torque Ti input from the electric motor 10 to the input shaft 16 in a predetermined torque increase slow change control section Tf in response to an increase from a zero value of the accelerator opening θacc. As shown in FIG. 2, the torque increase slow change control unit 34 suppresses the increase in the input torque Ti in the torque increase slow change control section Tf from the start point of increase (accelerator on) of the accelerator opening θacc until a prediction point that is experimentally predicted in advance to generate the backlash shock S, according to the increase rate of the input torque Ti (input torque Ti value and its time), and preferably makes the increase rate zero. That is, the torque increase slow change control unit 34 suppresses the increase in the input torque Ti within the torque increase slow change control section Tf experimentally set in advance at the prediction point.

[0019] The differential torque calculation unit 36 calculates the differential torque ΔT (= To - Ti) between the output torque To transmitted from the speed reducer 22 to the output shaft 18 and the input torque Ti input from the electric motor 10 to the input shaft 16, by converting it onto a common shaft that is either the input shaft 16 or the output shaft 18.

[0020] When the waveform of the differential torque ΔT at the rising of the input torque Ti (when the pulsation of the differential torque ΔT starts) after passing near the end (backlash region) of the torque increase slow change control section Tf is in the negative direction (downward convex), the timing control unit 38 delays the rising timing of the input torque Ti from the electric motor 10 by a certain amount compared to the previous control. When the waveform of the differential torque ΔT is in the positive direction (upward convex), the timing control unit 38 advances the rising timing of the input torque Ti from the electric motor 10 by a certain amount compared to the previous control. Also, when the waveform of the differential torque ΔT changes from the previous negative direction (downward convex) to the positive direction (upward convex) at the rising of the input torque Ti (when the pulsation of the differential torque ΔT starts), the timing control unit 38 does not change the rising timing of the input torque Ti from the electric motor 10.

[0021] Fig. 3 shows, in the upper part, the change waveforms of the input torque Ti and the output torque To when the backlash shock S does not occur at the end of the torque rise slow change control section Tf, and shows, in the lower part, the change waveform of the differential torque ΔT. Thus, even when the backlash shock S does not occur, since the response of the output torque To to the input torque Ti is delayed, the pulsation of the waveform of the differential torque ΔT starts from the negative direction (downward convex).

[0022] Fig. 4 shows, in the upper part, the torque change waveforms in the cases of the input torques Ti1, Ti2, and Ti3 with the rising timing of the input torque Ti shifted by 0.1 second in a state where the backlash shock S occurs at the end of the torque rise slow change control section Tf, and shows, in the lower part, the change waveforms of the differential torques ΔT1, ΔT2, and ΔT3. As shown in these waveforms, it can be seen that the rising of the input torque Ti can be optimally controlled based on either the positive direction (upward convex) or the negative direction (downward convex) of the waveform of the differential torque ΔT at the rising of the input torque Ti (at the start of the pulsation of the differential torque ΔT). In Fig. 4, in the case of the input torque Ti2 whose rising timing is in the same period as the backlash shock S, it becomes optimal, and the input torque Ti from the motor 10 can be quickly raised while suppressing the occurrence of the backlash shock S, and the responsiveness is enhanced.

[0023] Figure 5 is a flowchart illustrating the main parts of the control differential of the electronic control unit 30. In S1 of Figure 5, a signal representing the input torque Ti, a signal representing the output torque To, and the accelerator opening θacc are read. Next, in S2, the input torque Ti is converted onto the output shaft 18 based on the gear ratio of the reduction gear 22, or the output torque To is converted onto the input shaft 16 based on the gear ratio. In S3, the differential torque ΔT is calculated from the input torque Ti and output torque To converted onto the output shaft 18, or from the input torque Ti and the output torque To converted onto the input shaft 16. In S4, it is determined whether the pulsation waveform of the differential torque ΔT near the end of the torque increase gradual change control section Tf (backlash region) starts with an upward convexity. If this determination in S4 is denied (it is convex downward), in S5, the rising timing of the input torque Ti near the end of the torque increase gradual change control section Tf (backlash region) is delayed by a certain amount compared to the previous value.

[0024] However, if the judgment in S4 is affirmed, in S6 it is determined whether the waveform of the previous differential torque ΔT was a downward convex shape. If the judgment in S6 is denied, in S7 the rise timing of the input torque Ti near the end of the torque increase gradual change control section Tf (backlash region) is advanced by a certain amount compared to the previous value. However, if the judgment in S6 is affirmed, in S8 the rise timing of the input torque Ti near the end of the torque increase gradual change control section Tf (backlash region) is not changed, and the timing up to that point is maintained.

[0025] As described above, according to the electronic control device (control device) 30 of the electric vehicle (vehicle) 12 of this embodiment, the timing control unit 38 controls the rise timing of the input torque Ti from the electric motor (drive source) 10 from the torque rise gradual change control unit 34, based on the sign direction of the waveform of the differential torque ΔT calculated by the differential torque calculation unit 36 ​​at the start of pulsation near the end of the torque rise gradual change control section Tf. This makes it possible to quickly rise the input torque Ti from the electric motor 10 while suppressing the occurrence of rattling shock S.

[0026] Furthermore, according to the electronic control device 30 of the electric vehicle 12 of this embodiment, the timing control unit 38 delays the rise time of the input torque Ti from the electric motor 10 by a certain amount if the waveform at the start of pulsation of the differential torque ΔT is convex in the negative direction, advances the rise time of the input torque Ti from the electric motor 10 by a certain amount if the waveform at the start of pulsation of the differential torque ΔT is convex in the positive direction, and does not change the rise time of the input torque Ti from the electric motor 10 if the waveform at the start of pulsation of the differential torque ΔT changes from a convex negative direction in the previous instance to a convex positive direction in the current instance. As a result, the input torque Ti from the electric motor 10 can be quickly brought up while suppressing the occurrence of rattling shock S.

[0027] The above-described examples are embodiments of the present invention, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, without departing from its spirit. [Explanation of symbols]

[0028] 10: Electric motor (drive source), 12: Electric vehicle (vehicle), 14: Power transmission device (gear-type power transmission device), 20: Drive wheel, 30: Electronic control device (control device), 36: Differential torque calculation unit, 38: Timing control unit, Ti: Input torque, To: Output torque, ΔT: Differential torque

Claims

[Claim 1] A vehicle control device that includes a gear-type power transmission device in the power transmission path between a drive source and a drive wheel, and performs torque increase gradual change control to gradually change the increase in input torque from the drive source when switching from a non-driven state to a driven state, A differential torque calculation unit calculates the difference torque between the input torque from the drive source and the output torque of the gear-type power transmission device by converting it onto a common shaft, Includes a timing control unit that controls the rise timing of the input torque from the drive source from the torque rise control based on the sign direction of the waveform at the start of pulsation of the differential torque from the end of the torque rise control. A vehicle control device characterized by the following features.

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