Vehicle control system

Abstract

This invention provides a vehicle control device that performs the gear shift control required when driving in high-speed driving environments such as racetracks. [Solution] When the electronic control unit 60 performs an upshift to switch the gear ratio γ of the automatic transmission 22 to a smaller gear GP while the vehicle 10 is driving with the accelerator fully depressed, it controls the gear shift determination time TJP so that the gear shift execution time TGP and the time when the engine rotation speed Ne rises to the set target engine rotation speed Net occur simultaneously. When the vehicle 10 is driving uphill, the target engine rotation speed Net is set to a second predetermined value N2 which is greater than the first predetermined value N1 set when driving on a flat road. As a result, when the vehicle 10 is driving uphill, it continues to drive in the current gear GP until the engine rotation speed Ne rises to the second predetermined value N2, so that the gear shift control required when driving in a high-speed driving environment such as a circuit is performed.

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle including an engine and an automatic transmission.

Background Art

[0002] Vehicles including an engine and an automatic transmission that is provided in a power transmission path between the engine and drive wheels and in which a plurality of gear stages with different gear ratios are selectively established are well known. In shifting of the automatic transmission, for example, there is a predetermined delay time from the time point at which shifting is performed, that is, the start of gear stage switching is determined and an instruction to start is issued (hereinafter referred to as a shift determination point) to the time point at which shifting is actually performed (hereinafter referred to as a shift execution point) due to response delay of hydraulic control and the like, so shift control is performed in consideration of this delay time. For example, when performing an upshift that switches the gear ratio of the automatic transmission to a gear stage one step smaller while the vehicle is traveling on an uphill road with the accelerator fully open, the rate of change in vehicle speed during the period from the shift determination point to the shift execution point (hereinafter referred to as vehicle acceleration) is different from that when traveling on a flat road, so the vehicle speed at the shift execution point also changes accordingly, which may prevent an optimal shift operation from being obtained. As a countermeasure against this, Patent Document 1 describes a technique of calculating a predicted value of the vehicle speed at the shift execution point from the vehicle acceleration and the delay time, and performing shift control such that the predicted value becomes the same target vehicle speed as when traveling on a flat road. Further, Patent Document 2 discloses a technique of switching the shift determination point (shift map) to one for uphill roads and correcting the shift execution point to be equivalent to that when traveling on a flat road when the vehicle is traveling on an uphill road.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of Invention

[0004] For vehicles traveling on public roads, the point at which an upshift is executed with the accelerator fully depressed is determined by the relationship between the engine's torque characteristics and the automatic transmission's gear ratio. This point is where the engine torque is greatest, resulting in a smoother connection of the driving force. In other words, the gear change is performed at the point where the target vehicle speed (= target engine rotational speed) corresponds to the point where the engine torque is greatest. Since the engine has a torque characteristic where torque increases with increasing rotational speed and then decreases with increasing rotational speed after exceeding the rotational speed at which torque is maximum, the target engine rotational speed set for the shift execution point is set lower than the maximum engine rotational speed, which is set as the upper limit of the engine's rotational speed.

[0005] On the other hand, in high-speed driving environments such as circuits, and when driving on paved roads, there was a demand to increase the target engine speed set at the shift point to the maximum engine speed when shifting with the accelerator fully open. This is because, in circuit driving, it is desirable to prevent busy shifting during cornering and because the driving force decreases when a gear change is performed. Therefore, when driving on paved roads, it is desirable to continue driving in the current gear until the engine speed approaches the maximum engine speed. Thus, different gear shift control is required when driving in high-speed driving environments such as circuits and when driving on ordinary roads.

[0006] This invention was made against the above circumstances, and its objective is to provide a vehicle control device that performs the gear shift control required when driving in high-speed driving environments such as racetracks. [Means for solving the problem]

[0007] The gist of the first invention is a control device for a vehicle, comprising: (a) an engine and an automatic transmission provided in a power transmission path between the engine and the drive wheels, which selectively sets up a plurality of gears with different gear ratios, wherein the automatic transmission performs gear switching at a gear execution time predetermined after a gear shift determination time in which a gear shift is determined; (b) when an upshift is performed to switch the gear ratio of the automatic transmission to a smaller gear while the vehicle is traveling with the accelerator fully open, the gear shift determination time is controlled so that the gear shift execution time and the time when the engine speed rises to a set target engine speed are simultaneous; and (c) when the vehicle is traveling uphill, the target engine speed is set to a second predetermined value which is greater than the first predetermined value which is set when the vehicle is traveling on a flat road. [Effects of the Invention]

[0008] According to the first invention, when the control device performs an upshift to switch the gear ratio of the automatic transmission to a smaller gear while the vehicle is traveling with the accelerator fully depressed, it controls the timing of the gear shift determination so that the time of the gear shift execution and the time when the engine speed rises to a set target engine speed are simultaneous. When the vehicle is traveling uphill, the target engine speed is set to a second predetermined value which is greater than the first predetermined value which is set when the vehicle is traveling on a flat road. As a result, when the vehicle is traveling uphill, it continues to travel in the current gear until the engine speed rises to the second predetermined value, so that the gear shift control required when driving in a high-speed environment such as a circuit is performed. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram illustrates the schematic configuration of a vehicle to which the present invention is applied. [Figure 2] This is a schematic diagram illustrating the torque converter and automatic transmission installed in the vehicle shown in Figure 1. [Figure 3]Figure 2 is an operation table explaining the operating state of the friction engagement device when setting up the multiple gear stages of the automatic transmission. [Figure 4] This is a time chart illustrating an example of the control operation of an electronic control unit during upshifts when driving with the accelerator fully depressed. [Figure 5] This figure illustrates an example of a setting map when the second predetermined value is set according to the gradient of the uphill road. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Examples]

[0011] Figure 1 is a diagram illustrating the schematic configuration of a vehicle 10 to which the present invention is applied, as well as a diagram illustrating the main parts of the control system in the vehicle 10. In Figure 1, the vehicle 10 includes an engine 12 such as a gasoline engine or diesel engine that functions as a prime mover for driving, drive wheels 14, and a power transmission device 16 provided in the power transmission path between the engine 12 and the drive wheels 14. The power transmission device 16 is contained within a transmission case 18 (hereinafter referred to as case 18) which is a non-rotating member attached to the vehicle body and includes a known torque converter 20 as a fluid-type transmission device connected to the engine 12, an automatic transmission 22 connected to the torque converter 20, a propeller shaft 26 connected to an output shaft 24 which is the output rotating member of the automatic transmission 22, a differential gear 28 connected to the propeller shaft 26, and a pair of axles 30 connected to the differential gear 28.

[0012] Figure 2 is a schematic diagram illustrating the torque converter 20 and automatic transmission 22. The torque converter 20 and automatic transmission 22 are configured approximately symmetrically with respect to the centerline (axis RC), and the lower half of the centerline is omitted in Figure 2. Furthermore, the axis RC in Figure 2 represents the rotational axis of the engine 12 and the torque converter 20.

[0013] In Figure 2, the torque converter 20 is arranged to rotate around its axis RC and includes a pump impeller 20p connected to the engine 12, a turbine impeller 20t connected to the input shaft 32, which is the input rotating member of the automatic transmission 22, and a lock-up clutch 20c. The pump impeller 20p is connected to a mechanical oil pump 34, which is generated by the rotational drive of the engine 12 to generate hydraulic pressure for controlling the shifting of the automatic transmission 22 and supplying lubricating oil to various parts of the power transmission path of the power transmission device 16. The lock-up clutch 20c is, for example, a known hydraulic friction engagement device that connects the pump impeller 20p and the turbine impeller 20t. The lock-up clutch 20c can switch between control states such as engaged state, slip state, and released state by changing the engagement pressure from the linear solenoid valve SLU of the hydraulic control circuit 50 provided in the automatic transmission 22.

[0014] The automatic transmission 22 is a multi-stage planetary gear type automatic transmission that forms part of the power transmission path from the engine 12 to the drive wheels 14 and functions as a stepped automatic transmission that performs so-called clutch-to-clutch shifting, selectively setting up multiple gear stages GP with different gear ratios γ by releasing the release-side engaging device (release-side clutch) and engaging the engaging-side engaging device (engaging-side clutch) among the multiple friction engaging devices. The automatic transmission 22 has a double-pinion type first planetary gear unit 36, a Ravigneau-type single-pinion type second planetary gear unit 38 and a double-pinion type third planetary gear unit 40 on the same axis (on the axis RC), and shifts the rotation of the input shaft 32 to output power from the output shaft 24.

[0015] The first planetary gear unit 36, the second planetary gear unit 38, and the third planetary gear unit 40 are each composed of three rotating elements (rotating members), consisting of a sun gear (S1, S2, S3), a carrier (CA1, CA2, CA3) that supports the pinion gear (P1, P2, P3) so that it can rotate and revolve, and a ring gear (R1, R2, R3) that meshes with the sun gear via the pinion gear.

[0016] The above clutches C1, C2, C3, C4, and brakes B1, B2 (hereinafter simply referred to as clutches C, brakes B, or engagement devices when no particular distinction is made) are hydraulically driven friction engagement devices commonly used in known vehicular automatic transmissions, and are configured by wet multi-plate clutches or brakes pressed by a hydraulic actuator, band brakes tightened by a hydraulic actuator, and the like. The clutch C and brake B configured in this manner have their respective torque capacities (that is, engagement forces) varied by engagement pressures from linear solenoid valves SL1 to SL6 and the like included in a hydraulic control circuit 50 provided in the automatic transmission 22, so that engagement and disengagement are switched.

[0017] By controlling the engagement and disengagement of the clutches C and brakes B by the hydraulic control circuit 50, as shown in the engagement operation table of Figure 3, eight forward speeds (1st gear 1st, 2nd gear 2nd, 3rd gear 3rd, 4th gear 4th, 5th gear 5th, 6th gear 6th, 7th gear 7th, and 8th gear 8th) and one reverse speed (reverse gear Rev) gear stages GP are established in accordance with the driver's accelerator operation, vehicle speed V, and the like. The engagement operation table of Figure 3 summarizes the relationship between the gear stages GP and the respective operation states of the clutches C and brakes B, where "○" represents engagement, "◎" represents engagement only during, for example, driven operation, and a blank space represents disengagement.

[0018] Returning to Figure 1, the vehicle 10 is provided with an electronic control unit 60 including a control device for the automatic transmission 22 related to, for example, shift control of the automatic transmission 22. The electronic control unit 60 is configured to include a so-called microcomputer, and executes output control of the engine 12, shift control of the automatic transmission 22, and the like.

[0019] To the electronic control device 60, various actual values (for example, engine rotational speed Ne, transmission input shaft rotational speed Nin that is turbine rotational speed Nt, output shaft rotational speed Nout corresponding to vehicle speed V, accelerator opening degree θacc, throttle valve opening degree θth, operation position (also referred to as shift position or lever position) Psh of a shift lever 82 as a shift operation member, longitudinal acceleration Gx of the vehicle 10, travel mode signal Dmd, etc.) based on detection signals from various sensors provided in the vehicle 10 (for example, an engine rotational speed sensor 70, a turbine rotational speed sensor 72, an output shaft rotational speed sensor 74, an accelerator opening degree sensor 76, a throttle sensor 78, a shift position sensor 80, a G sensor 84, a travel mode setting switch 86, etc.) are respectively supplied.

[0020] The travel mode setting switch 86 is a switch for the driver to set the travel mode of the vehicle 10, and can switch between, for example, a first travel mode MD1 for traveling on general roads, and a second travel mode MD2 for traveling at a higher speed than the first travel mode on, for example, a circuit or the like. The set content is supplied to the electronic control device 60 as the travel mode signal Dmd.

[0021] From the electronic control device 60, an engine output control command signal Se for output control of the engine 12, a lockup hydraulic control command signal Sl for hydraulic control of the control states (engaged state, slip state, and released state) of the lockup clutch 20c, a shift hydraulic control command signal Sp for hydraulic control related to shifting of the automatic transmission 22, and the like are respectively output. For example, as the shift hydraulic control command signal Sp, command signals (instructed pressures) for driving the linear solenoid valves SL1 to SL6 that regulate the respective hydraulic pressures supplied to the hydraulic actuators of the clutch C and the brake B are output to the hydraulic control circuit 50.

[0022] The electronic control unit 60 performs gear shift control of the automatic transmission 22. For example, when the vehicle 10 is driving with the accelerator fully open (accelerator opening θacc = 100%), the electronic control unit 60 controls the automatic transmission 22 to perform an upshift, switching the gear ratio γ to a smaller gear GP, by instructing the gear GP switch at the gear shift determination point TJP, and so that the gear GP switch is performed at the gear shift execution point TGP, which is delayed by time Td from the gear shift determination point TJP. The gear shift determination point TJP is the point in time when the start of the gear GP switch is determined and a gear shift hydraulic control command signal Sp instructing the switch is output to the hydraulic control circuit 50, and corresponds to the "gear shift determination point" of the present invention. The gear shift execution point TGP is the point in time when the gear GP switch is actually performed, that is, when the inertia phase begins, and corresponds to the "gear shift execution point" of the present invention. The delay time Td is the time (period) required from the gear shift determination point TJP to the gear shift execution point TGP due to factors such as the response delay of the hydraulic control, and corresponds to the "predetermined period" in this invention. The delay time Td is a set value that has been determined in advance through design or experimentation. Furthermore, the delay time Td is kept constant by performing control that compensates for the effects of factors such as variations in hydraulic control and changes in oil temperature.

[0023] When the electronic control unit 60 performs an upshift while the vehicle is running with the accelerator fully depressed, it takes into account the delay time Td and controls the gear shift determination point TJP so that the gear shift execution point TGP, which occurs after the delay time Td from the gear shift determination point TJP, and the point at which the gear shift input shaft rotation speed Nin rises to the set target engine rotation speed Net occur simultaneously. Furthermore, the upshift here is an upshift while the vehicle 10 is running, and the lock-up clutch 20c is engaged. That is, the gear shift input shaft rotation speed Nin = engine rotation speed Ne, and the electronic control unit 60 controls the gear shift determination point TJP so that the gear shift execution point TGP and the point at which the engine rotation speed Ne rises to the target engine rotation speed Net occur simultaneously.Hereafter, the explanation will use the engine rotation speed Ne as the gear shift input shaft rotation speed Nin.

[0024] Figure 4 is a time chart illustrating an example of the control operation of the electronic control unit 60 when driving with the accelerator fully open, showing an example of the control operation when upshifting gear GP from 2nd gear to 3rd gear. In the time chart, the dashed line represents driving on a flat road with conventional control (hereinafter referred to as standard driving SD), the dotted line represents driving on an uphill road with conventional control (hereinafter referred to as uphill driving UD1), and the solid line represents driving on an uphill road with control to which the present invention is applied (hereinafter referred to as uphill driving UD2).

[0025] The detection of driving on an uphill road can be performed, for example, by calculating the actual acceleration αr, which is the current acceleration of the vehicle 10, from the rate of change of the engine rotational speed Ne during driving, i.e., the engine rotational acceleration αe. If the actual acceleration αr is less than or equal to a predetermined threshold than the flat road acceleration αv, which is obtained by dividing the driving torque to the vehicle 10 by the vehicle mass, it is determined that the vehicle is driving on an uphill road. Alternatively, the actual acceleration αr may be obtained from the rate of change of the vehicle speed V or the longitudinal acceleration Gx of the vehicle 10 from the G sensor 84.

[0026] In Figure 4, for standard driving SD and uphill driving UD1, the target engine speed Net for the upshift from 2nd gear to 3rd gear is set to a first predetermined value N1, which is initially set including driving on a flat road (Net=N1). In the case of standard driving SD (dash-dotted line), the gear shift hydraulic control command signal Sp is output at t10, which is the gear shift determination point TJP, and after a delay time Td, the gear shift GP is switched (switching from 2nd gear to 3rd gear) at t20, which is the gear shift execution point TGP, when the engine speed Ne rises to the first predetermined value N1.

[0027] The control of the gear shift determination point TJP, i.e., the detection of the gear shift determination point TJP, is performed, for example, by the following method. The gear shift determination point TJP is detected by detecting the point in time when the following equations (1) and (2) are satisfied, for example, with respect to the engine speed Ne, using the engine rotational accelerations αs and αu in the acceleration state before gear shifting and the delay time Td. Ne = Nsd = N1 - αs × Td ... (1) Ne = Nud1 = N1 - αu × Td ... (2)

[0028] Here, equation (1) is the judgment formula for standard driving SD, and equation (2) is the judgment formula for uphill driving UD1. Engine rotational acceleration αs is the engine rotational acceleration when driving on a flat road, and engine rotational acceleration αu is the engine rotational acceleration when driving on an uphill road. In Figure 4, in the case of standard driving SD, the shift judgment point TJP where equation (1) is true is detected at time t10 when the engine speed Ne rises to the value Nsd, and in the case of uphill driving UD1, the shift judgment point TJP where equation (2) is true is detected at time t11 when the engine speed Ne rises to the value Nud1.

[0029] In the case of uphill driving UD1 (dash-dot line), the engine rotational acceleration αe is smaller than the engine rotational acceleration αs when driving on a flat road. Therefore, the gear shift judgment point TJP is later at t11 ​​than at t10, and the gear shift execution point TGP is also later at t21 than at t20, when the gear position GP is switched (2nd gear → 3rd gear).

[0030] When the vehicle 10 is driving on a public road, the shift execution point TGP for upshifting with the accelerator fully open is set at a point where the engine torque is high, resulting in a good connection of the driving force, based on the relationship between the torque characteristics of the engine 12 and the gear ratio γ of the automatic transmission 22. In other words, it is set at a point where the target engine speed Net is high with high engine torque. The engine 12 has a torque characteristic where the torque increases with increasing engine speed Ne, and then decreases with increasing engine speed Ne after exceeding the rotational speed at which the torque is maximum. Therefore, the target engine speed Net, i.e., the first predetermined value N1, set at the shift execution point TGP is set to a suitable rotational speed that is lower than the maximum engine speed Nemax, which is set as the upper limit of engine speed Ne, and where the engine torque is high, which is determined through design or experimentation.

[0031] On the other hand, in high-speed driving environments such as circuits, and when driving on paved roads, there was a demand to increase the target engine speed Net set at the shift execution point TGP to the maximum engine speed Nemax when shifting with the accelerator fully open. This is because, in circuit driving, it is necessary to prevent busy shifting in corners and because the driving force decreases when a shift is performed. Therefore, when driving on paved roads, it is desirable to continue driving in the current gear GP until the maximum engine speed Nemax is reached. Thus, different shift control is required when driving in high-speed driving environments such as circuits and when driving on general roads.

[0032] Therefore, in the case of the electronic control device 60 of this embodiment, when the vehicle 10 is traveling uphill and the accelerator is fully open, the target engine speed Net is set to a second predetermined value that is greater than the first predetermined value N1, as shown in the uphill driving UD2 (solid line) in Figure 4 (Net=N2>N1). In the case of uphill driving UD2 (solid line), as in the case of standard driving SD and uphill driving UD1, the gear shift determination point TJP (time t12) is detected by detecting the time when the following equation (3) is satisfied. Ne = Nud2 = N2 - αu × Td ... (3)

[0033] In the case of uphill driving UD2 (solid line), the gear shift hydraulic control command signal Sp is output at t12 (gear shift judgment point TJP), which is later than t11, and the gear shift (2nd gear → 3rd gear) is performed at t22 (gear shift execution point TGP), when the engine rotation speed Ne rises to the second predetermined value N2 after a delay time Td. As a result, when vehicle 10 is driving on an uphill road, it continues to drive in the current gear GP (2nd gear) until the engine rotation speed Ne rises to the second predetermined value N2, so that the gear shift control required when driving in high-speed driving environments such as circuits is performed.

[0034] Furthermore, while Figure 4 shows an example of upshifting gear GP from 2nd gear to 3rd gear, the same applies to upshifts between other gear GPs, such as 1st gear → 2nd gear → 4th gear → 4th gear → 4th gear → 5th gear, ..., 7th gear → 8th gear. In these cases, a first predetermined value N1 or a second predetermined value N2 is set as the target engine speed Net.

[0035] Preferably, the first predetermined value N1 is individually set to a suitable value that has been determined in advance through design or experimentation for each step between gear stages GP. This allows for suitable upshifting based on the setting of the first predetermined value N1 for each step between gear stages GP.

[0036] Preferably, the target engine speed Net is set to a second predetermined value N2 when the vehicle 10 is in the second driving mode MD2 and is traveling uphill, and to a first predetermined value N1 when at least one of the following conditions is met: the vehicle is in the first driving mode MD1 or is not traveling uphill. For example, even when the vehicle 10 is traveling downhill, the target engine speed Net is set to the first predetermined value N1. This ensures that the gear shift control required for both driving on public roads and driving in high-speed environments such as circuits is performed.

[0037] Preferably, the second predetermined value N2 is set to the maximum engine speed Nemax, which is set as the upper limit of the engine speed Ne. As a result, when the vehicle 10 is traveling uphill, it continues to travel in the current gear GP until the engine speed Ne rises to the maximum engine speed Nemax, thus providing the gear shift control required when driving in high-speed environments such as a circuit.

[0038] Also, preferably, the second predetermined value N2 is set such that when the climbing gradient Slo of the uphill road during traveling is equal to or less than a predetermined gradient Nslo (Slo≦Nslo), the second predetermined value N2 increases as the climbing gradient Slo increases and does not exceed the maximum engine rotation speed Nemax, and when the climbing gradient Slo is greater than the predetermined gradient Nslo (Slo>Nslo), the second predetermined value N2 is set to the maximum engine rotation speed Nemax. The climbing gradient Slo is calculated, for example, by applying the actual acceleration αr and the flat road acceleration αv to a gradient calculation map prepared in advance. FIG. 5 shows an example of a setting map when the second predetermined value is set according to the climbing gradient Slo. As described above, the second predetermined value N2 increases from the first predetermined value N1 to the maximum engine rotation speed Nemax (N1<N2≦Nemax) while the climbing gradient Slo is up to the predetermined gradient Nslo (0<Slo≦Nslo), and is set to the maximum engine rotation speed Nemax (N2=Nemax) when the climbing gradient Slo is greater than the predetermined gradient Nslo (Slo>Nslo). As the predetermined gradient Nslo, a suitable value obtained in advance by design or experiment is set. Thereby, when the vehicle 10 is traveling on an uphill road, the second predetermined value N2 is increased as the climbing gradient Slo increases, and traveling is continued at the current gear stage GP until the engine rotation speed Ne rises to the second predetermined value N2, so that shift control required when traveling in a high-speed traveling environment such as a circuit is performed.

[0039] As described above, according to the present embodiment, when performing an upshift for switching the gear ratio γ of the automatic transmission 22 to the gear stage GP that is one step smaller during traveling of the vehicle 10 in the accelerator fully opened state, the electronic control device 60 controls the shift determination time point TJP such that the shift execution time point TGP and the time point at which the engine rotation speed Ne rises to the set target engine rotation speed Net coincide with each other, and when the vehicle 10 is traveling on an uphill road, the target engine rotation speed Net is set to the second predetermined value N2 that is larger than the first predetermined value N1 set when traveling on a flat road. Thereby, when the vehicle 10 is traveling on an uphill road, traveling is continued at the current gear stage GP until the engine rotation speed Ne rises to the second predetermined value N2, so that shift control required when traveling in a high-speed traveling environment such as a circuit is performed.

[0040] Furthermore, according to this embodiment, the first predetermined value N1 is individually set to a suitable value that has been determined in advance through design or experimentation for each step between gear stages GP. This ensures that upshifts based on the setting of the first predetermined value N1 are performed suitably for each step between gear stages GP.

[0041] Furthermore, according to this embodiment, the vehicle 10 can switch between a first driving mode MD1 and a second driving mode MD2 that drives at a higher speed than the first driving mode. The target engine speed Net is set to a second predetermined value N2 when the vehicle 10 is in the second driving mode MD2 and is driving uphill, and to a first predetermined value N1 when the vehicle 10 is in the first driving mode MD1 and is not driving uphill. This enables the shift control required for both driving on public roads and driving in high-speed environments such as circuits.

[0042] Furthermore, according to this embodiment, the second predetermined value N2 is set to the maximum engine speed Nemax, which is set as the upper limit of the engine speed Ne. As a result, when the vehicle 10 is traveling uphill, it continues to travel in the current gear GP until the engine speed Ne rises to the maximum engine speed Nemax, thus providing the gear shift control required when driving in high-speed environments such as a circuit.

[0043] Furthermore, according to this embodiment, the second predetermined value N2 is set such that, when the uphill gradient Slo of the uphill road during driving is less than or equal to the predetermined gradient Nslo (Slo ≤ Nslo), the value increases as the uphill gradient Slo increases, and does not exceed the maximum engine speed Nemax. When the uphill gradient Slo is greater than the predetermined gradient Nslo (Slo > Nslo), the value is set to the maximum engine speed Nemax. As a result, when the vehicle 10 is driving on an uphill road, the second predetermined value N2 increases as the uphill gradient Slo increases, and driving continues in the current gear GP until the engine speed Ne rises to the second predetermined value N2, thus providing the gear shift control required when driving in high-speed driving environments such as circuits.

[0044] Although embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other embodiments.

[0045] For example, in the above-described embodiment, the vehicle 10 was a vehicle powered by an engine 12, but it may also be a hybrid electric vehicle (HEV) powered by both an engine and an electric motor. The present invention can be applied by considering the rotational speed input from the power source to the automatic transmission as the engine rotational speed Ne.

[0046] Furthermore, although the automatic transmission 22 in the above embodiment was an 8-speed stepped transmission, the number of gears may be different from 8. It is sufficient that multiple gears GP with different gear ratios γ can be selectively established during stepped shifting.

[0047] Furthermore, although the vehicle 10 was equipped with a torque converter 20 in the above-described embodiment, the torque converter 20 is not required, and a clutch or the like may be provided instead of the torque converter 20.

[0048] It should be noted that the above-described embodiment is merely one example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of Symbols]

[0049] 10: Vehicle 12: Engine 14: Drive wheels 22: Automatic transmission 60: Electronic control unit (control unit) GP: Gear stage MD1: First driving mode MD2: Second driving mode N1: First predetermined value N2: Second predetermined value Ne: Engine rotational speed Nemax: Maximum engine rotational speed Net: Target engine rotational speed Nslo: Predetermined gradient Slo: Climbing gradient Td: Delay time (predetermined period) TGP: Gear shift execution point (time of gear shift execution) TJP: Gear shift judgment point (time of gear shift judgment) γ: Gear ratio

Claims

1. A control device for a vehicle comprising an engine and an automatic transmission provided in the power transmission path between the engine and the drive wheels, which selectively enables a plurality of gears with different gear ratios, wherein the automatic transmission performs the gear change at a gear execution time predetermined after a gear change determination time when a gear change is determined, When the vehicle is being driven with the accelerator fully depressed, and an upshift is performed to switch the gear ratio of the automatic transmission to a lower gear, the timing of the gear shift determination is controlled so that the time of the gear shift execution and the time when the engine speed increases to a set target engine speed occur simultaneously. When the vehicle is traveling uphill, the target engine speed is set to a second predetermined value that is greater than the first predetermined value set when the vehicle is traveling on a flat road. A vehicle control device characterized by the following features.

2. The first predetermined value is set to a separate value for each step between the multiple gear stages that are upshifted. The vehicle control device according to feature 1.

3. The vehicle is capable of switching between a first driving mode and a second driving mode that operates at a higher speed than the first driving mode. The target engine speed is set to the second predetermined value when the second driving mode is in use and the vehicle is traveling uphill, and to the first predetermined value when at least one of the following conditions is met: the first driving mode is in use and the vehicle is not traveling uphill. The vehicle control device according to feature 2.

4. The second predetermined value is set to the maximum engine speed, which is set as the upper limit of the engine speed. A vehicle control device according to any one of claims 1 to 3.

5. The second predetermined value is set such that, if the incline of the uphill road during driving is less than or equal to the predetermined incline, it increases as the incline increases, and does not exceed the maximum engine speed set as the upper limit of the engine speed; if the incline is greater than the predetermined incline, it is set to the maximum engine speed. A vehicle control device according to any one of claims 1 to 3.

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