Vehicle control device

Abstract

To provide a vehicle control device capable of improving responsiveness when switching from a non-power transmission range to a power transmission range while suppressing deterioration in fuel efficiency.SOLUTION: A vehicle 10 includes an automatic transmission 20 provided in a power transmission route PT between an engine 12, which is a drive source, and a pair of driving wheels 24, in which when a predetermined number of engagement devices CB for speed change of a plurality of engagement devices for speed change are brought into an engagement state in a power transmission range, a predetermined shift stage is selectively formed out of a plurality of shift stages. In a case where a part (a clutch C2 and a brake B2) of the predetermined number of engagement devices CB for speed change brought into the engagement state in the power transmission range is brought into the engagement state in an N range or a P range, an electronic control device 90 maintains the part in the engagement state if a rotational speed difference ΔNin(=|Nin-Ne|), which is a drag amount in the automatic transmission 20, is less than a speed difference determination value ΔNin_jdg, and, if not, returns it in a release state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle equipped with an automatic transmission, which is provided in a power transmission path between a drive source and a pair of drive wheels, and in which a predetermined gear shift stage is selectively formed from among a plurality of gear shift stages by engaging a predetermined number of a plurality of gear shift engagement devices in a power transmission range. [Background technology]

[0002] There is known a control device for a vehicle equipped with an automatic transmission that is provided in a power transmission path between an engine and a pair of drive wheels, and in which a predetermined number of a plurality of shift engagement devices are brought into an engaged state in a power transmission range to selectively establish a predetermined shift stage from among a plurality of shift stages. For example, the device described in Patent Document 1 is such a control device. In the vehicle described in Patent Document 1, the engagement and disengagement state (engaged state or released state) of the shift engagement devices is controlled according to a predetermined engagement operation table according to the shift range (power transmission range or non-power transmission range) of the automatic transmission. For example, when it is in the non-power transmission range, all the shift engagement devices are brought into a released state. On the other hand, when it is in the power transmission range, a predetermined number of the shift engagement devices are brought into an engaged state so that a predetermined shift stage is selectively established. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-146777 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in order to improve responsiveness when switching from the non-power transmission range to the power transmission range due to garage operation, etc., it is conceivable to have some of the predetermined number of shift engagement devices that are engaged in the power transmission range be in an engaged state even when in the non-power transmission range. However, in such an embodiment, there is a risk of fuel economy decreasing if drag occurs for some reason within the automatic transmission.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that suppresses a decrease in fuel efficiency and improves responsiveness when switching from the non-power transmission range to the power transmission range. [Means for solving the problem]

[0006] The gist of the present invention is a control device for a vehicle that includes a drive source and an automatic transmission that is provided in a power transmission path between the drive source and a pair of drive wheels, and in which a predetermined gear stage is selectively formed from a plurality of gear stages by engaging a predetermined number of a plurality of gear shift engagement devices in a power transmission range, wherein, in a non-power transmission range, when a portion of the predetermined number of the gear shift engagement devices that are engaged in the power transmission range are engaged, the portion is maintained in an engaged state when the drag amount within the automatic transmission is less than a predetermined judgment value, and the portion is returned to a disengaged state when this is not the case. Effect of the Invention

[0007] According to the vehicle control device of the present invention, in the non-power transmission range, when some of the predetermined number of the shift engagement devices that are engaged in the power transmission range are engaged, the some are maintained in the engaged state when the amount of drag in the automatic transmission is less than a predetermined judgment value, and otherwise the some are returned to a disengaged state, thereby ensuring responsiveness when switching from the non-power transmission range to the power transmission range and suppressing deterioration of fuel efficiency due to drag in the automatic transmission. [Brief description of the drawings]

[0008] [Figure 1] 1A is a schematic diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, in which (a) is a schematic diagram of the vehicle and a functional block diagram showing the main parts of the control functions for various controls in the vehicle, and (b) is an engagement operation table that explains the relationship between the shift operation of an automatic transmission and the combination of the engagement and disengagement states of the shift engagement devices used therein. [Diagram 2] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to an embodiment of the present invention, in which (a) is a schematic diagram of the vehicle 10 and a functional block diagram showing the main parts of the control functions for various controls in the vehicle 10, and (b) is an engagement operation table that explains the relationship between the shift operation of the automatic transmission 20 and the combinations of the engagement and disengagement states of the shift engagement device CB used therein.

[0011] The vehicle 10 includes, in a power transmission path PT between the engine 12, which is a drive source for traveling, and a pair of drive wheels 24, in order from the engine 12 side, an engine connecting shaft 30, a torque converter 14, an input shaft 32, an automatic transmission 20, an output shaft 34, a differential 22, etc., in a case 16, as well as a pair of axles 36 connected to the differential 22, all of which are well-known configurations. A lock-up clutch LU is provided between the pump wheel and turbine wheel of the torque converter 14. The vehicle 10 also includes a hydraulic control circuit 40, a shift lever 50, and an electronic control device 90.

[0012] The vehicle 10 has, for example, a P range, an R range, an N range, and a D range as shift ranges. The shift lever 50 is an operator for operating to each of the operating positions POSsh, for example, "P", "R", "N", and "D". "P" is an operating position for setting the automatic transmission 20 to the P range (= a parking range in which the automatic transmission 20 is in a neutral state and the pair of drive wheels 24 are mechanically fixed so as not to rotate). "R" is an operating position for setting the automatic transmission 20 to the R range (= a range that allows the vehicle 10 to travel backwards). "N" is an operating position for setting the automatic transmission 20 to the N range (= a range in which the automatic transmission 20 is in a neutral state). "D" is an operating position for setting the automatic transmission 20 to the D range (= a range that allows forward travel by executing shift control of the automatic transmission 20). The R range and the D range are "power transmission ranges" in which the automatic transmission 20 transmits the power transmitted from the engine 12 to the pair of drive wheels 24. The P range and N range are “non-power transmission ranges” in which the automatic transmission 20 does not transmit the power transmitted from the engine 12 to the pair of drive wheels 24 but blocks it.

[0013] The automatic transmission 20 is, for example, a planetary gear type multi-stage transmission having a plurality of hydraulic friction engagement devices (hereinafter referred to as "shift engagement devices CB") and performing so-called clutch-to-clutch shifting by switching between engagement and disengagement of one of the plurality of shift engagement devices CB. In the automatic transmission 20, a predetermined gear stage is formed according to a shift range and, for example, an accelerator opening θacc [%], a vehicle speed V [km / h], etc.

[0014] The gear shifting engagement devices CB include, for example, clutches C1 to C4 and brakes B1 to B2. In the engagement operation table shown in FIG. 1(b), "◯" indicates an engaged state, "blank" indicates a released state, and "△" indicates a state in which either the engaged state or the released state is possible. In the automatic transmission 20, a predetermined gear shift stage is selectively formed from eleven gear shift stages (ten gear shift stages for the D range and one gear shift stage for the R range) having different gear ratios γ by selectively engaging three of the multiple gear shifting engagement devices CB in the D range and the R range. The gear shift ratio γ is the ratio (=Nin / Nout) between the input shaft rotation speed Nin [rpm] and the output shaft rotation speed Nout [rpm]. The input shaft rotation speed Nin is the rotation speed of the input shaft 32, and the output shaft rotation speed Nout is the rotation speed of the output shaft 34. The "three" selectively engaged corresponds to the "predetermined number" in the present invention. In the D range, the gear ratio γ of the first gear 1st, which is the lowest gear, is the largest, and the gear ratio γ decreases as the gear becomes higher.

[0015] The hydraulic control circuit 40 uses, for example, hydraulic oil discharged by the oil pump 18 as the source pressure and supplies regulated hydraulic pressure to actuators that control the engagement and disengagement states of the lock-up clutch LU of the torque converter 14 and the gear shift engagement device CB.

[0016] The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 90 corresponds to the "control device" of the present invention.

[0017] The electronic control device 90 receives various signals (e.g., engine speed Ne [rpm] which is the rotation speed of the engine 12, input shaft rotation speed Nin, output shaft rotation speed Nout corresponding to vehicle speed V, accelerator opening θacc, operation position POSsh, oil temperature THoil [°C] which is the temperature of the hydraulic oil, etc.) based on detection values ​​by various sensors provided on the vehicle 10 (e.g., engine speed sensor 70, input shaft rotation speed sensor 72, output shaft rotation speed sensor 74, accelerator opening sensor 76, operation position sensor 78, oil temperature sensor 80, etc.).

[0018] The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, an LU control signal Slu for controlling the engagement and disengagement of the lock-up clutch LU, and a shift control signal Sat for controlling the shifting of the automatic transmission 20) to each device (e.g., the engine 12, the hydraulic control circuit 40, etc.) provided in the vehicle 10.

[0019] The electronic control unit 90 functionally comprises a range determination unit 92, a condition determination unit 94, a drag determination unit 96, and an engagement control unit 98.

[0020] The range determination unit 92 determines whether the range is N range or P range based on the operation position POSsh.

[0021] The condition determination unit 94 determines whether or not predetermined conditions are met for executing a "partial engagement control" described below regardless of the presence or absence of drag in the automatic transmission 20. The predetermined conditions are: (a) the vehicle speed V is equal to or greater than a vehicle speed determination value V_jdg, (b) the accelerator opening θacc is equal to or greater than an opening determination value θacc_jdg, (c) the oil temperature THoil is less than the oil temperature determination value THoil_jdg, and (d) the difference between the engine rotation speed Ne and the target idle rotation speed Nidl_tgt (=|Ne-Nidl_tgt|) is equal to or greater than the rotation speed determination value Ne_jdg. If any of (a) to (d) is met, it is determined that the predetermined conditions are met.

[0022] The satisfaction of the predetermined condition (a) is, for example, when the range is set to N while driving, and is a situation in which priority is given to responsiveness when switching from N range to D range (hereinafter, referred to as "drivability"). The vehicle speed determination value V_jdg is a predetermined value (for example, a value close to zero) that is experimentally or design-wise determined in advance in order to determine whether or not the vehicle is driving. The satisfaction of the predetermined condition (b) is a situation in which priority is given to drivability, since it is considered that the driver intends to drive the vehicle 10. The opening determination value θacc_jdg is a predetermined value (for example, a value close to zero) that is experimentally or design-wise determined in advance in order to determine whether or not the driver intends to drive the vehicle 10. The satisfaction of the predetermined condition (c) is a situation in which priority is given to drivability, since a longer time is required to switch the shift engagement device CB from a released state to an engaged state, compared to a case in which the predetermined condition (c) is not satisfied. The oil temperature determination value THoil_jdg is a predetermined value determined experimentally or by design in order to determine whether the time required to switch the gear shift engagement device CB from a released state to an engaged state falls outside the allowable range and thus has a large impact on the deterioration of drivability. When the oil temperature THoil is low, the viscosity of the hydraulic oil increases, and the time required to switch the gear shift engagement device CB from a released state to an engaged state falls outside the allowable range. The establishment of the predetermined condition (d) is a situation in which the operation of the engine 12, which is the driving source, is unstable, and the determination by the drag determination unit 96, which will be described later, becomes inaccurate. The rotation speed determination value Ne_jdg is a predetermined value (for example, a value close to zero) determined experimentally or by design in order to determine whether the operation of the engine 12 is unstable. Therefore, when any of the predetermined conditions (a) to (c) is established, partial engagement control is executed to prioritize drivability over fuel economy. When the predetermined condition (d) is met, the determination by the drag determination unit 96 becomes inaccurate, and therefore partial engagement control is executed, giving priority to drivability.

[0023] When the range determination unit 92 determines that the range is the N range or the P range and the condition determination unit 94 determines that the predetermined condition is not satisfied, the engagement control unit 98 executes partial engagement control. The "partial engagement control" is a control in which, in the non-power transmission range, some of the three shift engagement devices CB that are engaged when the range is switched to the power transmission range are engaged. In this embodiment, for example, in the P range, the clutch C2 and the brake B2, which are two of the three shift engagement devices CB that are engaged in the first gear shift stage 1st of the D range or the R range, are engaged. In the partial engagement control, while maintaining the P range, two of the three shift engagement devices CB that are engaged in the first gear shift stage 1st of the D range or the R range are engaged in advance. As a result, the three shift engagement devices CB are engaged more quickly when the range is switched from the P range to the D range or the R range compared to when the partial engagement control is not executed, thereby improving drivability.

[0024] When the engagement control unit 98 executes the partial engagement control, the drag determination unit 96 determines whether the rotation speed difference ΔNin (=|Nin-Ne|) [rpm] is less than the speed difference determination value ΔNin_jdg. The speed difference determination value ΔNin_jdg is a predetermined value that is experimentally or design-wise determined in advance to determine whether the drag in the automatic transmission 20 is within an allowable range. When there is no drag in the automatic transmission 20, the rotation speed difference ΔNin is determined by the difference between the rotation speed Np (=Ne) of the pump impeller and the rotation speed Nt (=Nin) of the turbine impeller. For example, the difference between the rotation speed Np and the rotation speed Nt when the lock-up clutch LU is in a released state is determined in advance by the performance of the torque converter 14. When there is drag in the automatic transmission 20, the rotation speed difference ΔNin becomes even larger than the difference between the rotation speed Np and the rotation speed Nt that is determined in advance by the performance of the torque converter 14. It should be noted that the "rotation speed difference ΔNin" and the "speed difference judgment value ΔNin_jdg" correspond to the "drag amount" and the "predetermined judgment value" in the present invention, respectively.

[0025] When the engagement control unit 98 determines that the rotational speed difference ΔNin is less than the speed difference determination value ΔNin_jdg, the engagement control unit 98 maintains the engaged state of the clutch C2 and the brake B2. When the engagement control unit 98 determines that the rotational speed difference ΔNin is equal to or greater than the speed difference determination value ΔNin_jdg, the engagement control unit 98 returns the clutch C2 and the brake B2 from the engaged state to the released state.

[0026] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control device 90 shown in Fig. 1. The flowchart in Fig. 2 is repeatedly executed.

[0027] First, in step (hereinafter, step will be omitted) S10, it is determined whether the range is N or P. If the determination in S10 is YES, it is determined in sequence in S20 to S50 whether a predetermined condition is satisfied. If the determinations in S20 to S50 are all NO, partial engagement control is executed in S60, and it is determined in S70 whether the rotation speed difference ΔNin is less than the speed difference determination value ΔNin_jdg. If any of the determinations in S20 to S50 are YES, partial engagement control is executed in S80. If the determination in S70 is YES, the clutch C2 and the brake B2 are maintained in an engaged state in S90. If the determination in S70 is NO, the clutch C2 and the brake B2 are returned from an engaged state to a released state in S100. If the determination in S10 is NO, in S110, the engagement / disengagement control of the gear shift engagement device CB is executed according to the shift range based on the engagement operation table. After execution of S80 to S110, all of the processes are returned.

[0028] According to this embodiment, in the N range or P range, when the clutch C2 and the brake B2, which are two of the three shift engagement devices CB that are engaged in the first gear 1st in the D range or the R range, are engaged, if the rotational speed difference ΔNin is less than the speed difference determination value ΔNin_jdg, the clutch C2 and the brake B2 are maintained in the engaged state, and otherwise the clutch C2 and the brake B2 are returned to the released state. This ensures drivability while suppressing deterioration of fuel economy due to dragging in the automatic transmission 20.

[0029] It should be noted that the above is an embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0030] In the above embodiment, the difference such as the rotation speed difference ΔNin (=|Nin-Ne|) corresponds to the "drag amount" in the present invention, but this is not limited thereto. For example, a rotation speed ratio such as |Nin / Ne| may correspond to the "drag amount" in the present invention. In this embodiment, the drag determination unit 96 determines whether |Nin / Ne| is less than a predetermined rotation speed ratio. For example, the predetermined rotation speed ratio is "1-ΔNin_jdg / Ne".

[0031] In the above-described embodiment, two of the engagement devices CB for shifting, the clutch C2 and the brake B2, are engaged in the "partial engagement control", but this is not limited thereto. For example, one of the engagement devices CB for shifting, the clutch C2 and the brake B2, may be engaged.

[0032] In the above embodiment, it is determined whether any of the predetermined conditions (a) to (d) for executing the "partial engagement control" is satisfied regardless of the presence or absence of dragging in the automatic transmission 20, but this is not limiting. For example, it may be determined whether only some of the predetermined conditions (a) to (d) are satisfied, or it may be determined that none of the predetermined conditions (a) to (d) are satisfied.

[0033] In the above-described embodiment, the torque converter 14 is provided between the engine 12, which is the driving source, and the automatic transmission 20, but the present invention is not limited to this. For example, the present invention is also applicable to an embodiment in which a starting clutch that connects and disconnects the power transmission between the driving source and the automatic transmission 20 is provided instead of the torque converter 14.

[0034] For example, in a configuration in which a starting clutch is provided, when the starting clutch is engaged in the non-power transmission range, it is possible to execute substantially the same control as in the above-described embodiment. When the starting clutch is engaged, the input shaft rotation speed Nin is equal to the engine rotation speed Ne. Therefore, the method of determining whether dragging in the automatic transmission 20 is within an allowable range is different. For example, when the clutch C2 and the brake B2 are engaged and dragging is present, it is determined whether the rotation speed of the gears rotated in the automatic transmission 20 is less than a predetermined rotation speed.

[0035] For example, in a mode in which a starting clutch is provided, even when the starting clutch is released in the non-power transmission range, substantially the same control as in the above embodiment can be executed, but the method of determining whether the drag in the automatic transmission 20 is within the allowable range is different. For example, when the vehicle 10 is changed from a running state to a stopped state and the operating position POSsh is operated from "D" to "N", the starting clutch is released and the automatic transmission 20 is set to the N range. When the automatic transmission 20 is set to the N range, the gears and the like in the automatic transmission 20 maintain the rotation when the vehicle was in the running state due to inertia. Therefore, when the rate of decrease in the rotation speed of the gears and the like in the automatic transmission 20 when the partial engagement control is executed (= the amount of decrease in the rotation speed per hour) is smaller than a predetermined decrease determination value, it is determined that the drag in the automatic transmission 20 is within the allowable range. [Explanation of symbols]

[0036] 10: vehicle, 12: engine (drive source), 20: automatic transmission, 24: pair of drive wheels, 90: electronic control device (control device), CB: gear shift engagement device, PT: power transmission path, ΔNin: rotational speed difference (drag amount), ΔNin_jdg: speed difference judgment value (predetermined judgment value)

Claims

[Claim 1] A control device for a vehicle including a drive source and an automatic transmission that is provided in a power transmission path between the drive source and a pair of drive wheels, and in which a predetermined gear shift stage is selectively established from among a plurality of gear shift stages by bringing a predetermined number of a plurality of gear shift engagement devices into an engaged state in a power transmission range, In a non-power transmission range, when a part of the predetermined number of the shift engagement devices that are engaged in the power transmission range is engaged, if a drag amount in the automatic transmission is less than a predetermined judgment value, the part is maintained in an engaged state, and if not, the part is returned to a released state. A vehicle control device comprising:

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