JPH09287651A - Automatic shift control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically provide excellent engine brake performance during running on an upward slope and excellent acceleration performance during running on a downward slope, without mounting a novel sensor on a vehicle. SOLUTION: The ECU of this system decides the target speed ratio of a CVT according to the grade of a running road for a vehicle calculated by using an output from a various sensors mounted on a vehicle. Namely, when a grade calculating part 47 estimates the grade of a running road by using acceleration resistance torque calculated by an acceleration torque calculating part 45, plane running resistance torque calculated by a running resistance calculating part 43, output shaft torque of the CVT calculated by a torque calculating part 42, a target shift calculating part 48 corrects the target shift ratio of the CVT by using a correction value ipc obtained from a given map according to the magnitude of a grade estimated by a running resistance detecting part 43. A shift operation command output part 49 controls the CVT by using a target shift ratio calculated by the target shift calculating part 48.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control system for improving drivability when traveling on a road with a steep slope.

[0002]

2. Description of the Related Art In a conventional CVT system, a continuously variable transmission (hereinafter referred to as CVT) that follows a shift schedule as shown in FIG. 8A by an ECU so as to suppress shift shock and transmission loss. ) Gear change control is being performed. However, the conventional CVT system has a drawback in that when the driver's driving skill is inadequate, safety cannot be ensured when the vehicle approaches a slope. That is, when the vehicle is approaching a steep downhill slope, the driver normally adjusts the accelerator pedal so that the vehicle speed does not accelerate. As a result, the throttle valve is closed in conjunction with the accelerator pedal, so in the shift schedule of FIG. 8 (a), the running state of the vehicle is lower than the operating point a when the vehicle is approaching a slope, Since the vehicle shifts to the operating point c, the vehicle accelerates against the driver's intention. Therefore, if the driver is skilled in driving, at this time, the range is switched to a mode in which the engine speed is set to a higher value, which is generally called a sports mode, and the engine brake is effectively used to effectively use the engine brake. Acceleration can be suppressed. That is, when the range is set to the sports mode, the traveling state of the vehicle changes in the area surrounded by O-A-B-C-E-F-A-O in FIG. 8B. As a result, the running state of the vehicle is
It shifts to an operating point D with a larger gear ratio. Therefore, the vehicle travels downhill while effectively applying engine braking.

However, a driver unfamiliar with driving who cannot switch the range in a timely manner tends to frequently use the foot brake rather than actively switching the range while traveling on a downhill. It is in. As a result, brake wear is promoted.

On the other hand, if the accelerator pedal is further pressed when traveling uphill, a phenomenon opposite to that when traveling downhill occurs. That is, in the shift schedule of FIG. 8 (a), the running state of the vehicle shifts to an operating point on the lower side than the operating point when the vehicle approaches a slope, but a considerable increase in accelerator or range Without switching, the vehicle will not perform the intended acceleration.

Therefore, in order to solve such a problem, a continuously variable transmission for a vehicle disclosed in Japanese Patent Laid-Open No. 63-121537 is proposed to improve engine braking performance and acceleration performance when traveling on a road surface having a slope. A control device has been proposed. The control device for a continuously variable transmission for a vehicle disclosed in Japanese Patent Laid-Open No. 63-121537 does not calculate a vehicle speed detected by an output shaft rotation sensor and a throttle valve opening detected by a throttle valve opening sensor. The target gear ratio of the gear transmission is appropriately corrected using a speed ratio correction amount determined by the vehicle body inclination angle that is sequentially detected by the vehicle inclination angle sensor. Therefore, the target speed ratio of the continuously variable transmission is set to a value that is suitable for the gradient of the vehicle's road, so that excellent engine braking performance is automatically exerted during uphill driving. Excellent acceleration performance is automatically exerted during driving. That is, if this control device is mounted on a vehicle, both traveling safety and traveling performance of the vehicle can be ensured.

[0006]

However, when the control device for a continuously variable transmission for a vehicle described in Japanese Patent Laid-Open No. 63-121537 is mounted on a vehicle, the vehicle inclination for detecting the gradient of the traveling path of the vehicle. The angle sensor needs to be attached to the vehicle. That is, the addition of such a new element directly leads to an increase in vehicle manufacturing cost.

Therefore, the present invention controls an automatic transmission that automatically exhibits excellent engine braking performance when traveling downhill and excellent acceleration performance when traveling uphill without installing a new sensor on the vehicle. The purpose is to provide a device.

[0008]

In order to solve the above problems, the present invention controls the gear ratio of a continuously variable transmission mounted on a vehicle in accordance with the traveling state of the vehicle detected during traveling. A shift control device, which stores a correspondence information that uniquely associates a target speed ratio of the continuously variable automatic transmission with a road gradient, and a running resistance torque and acceleration of the vehicle as a running state of the vehicle. Detection means for detecting torque and output shaft torque of the continuously variable transmission; gradient estimation means for estimating a gradient of a road surface on which the vehicle is traveling from the traveling state of the vehicle detected by the detection means; When the slope of the road surface estimated by the estimating means is within a predetermined range, the determining means determines that the road surface on which the vehicle is traveling is a slope, and the shift control device determines that the vehicle is Road surface When it is determined that the road is a slope, the target speed ratio of the continuously variable transmission associated with the slope of the road surface estimated by the slope estimating unit by the correspondence information stored in the storage unit is used. Provided is a shift control device characterized by controlling a gear ratio of the continuously variable transmission. Further, in accordance with a running state of the vehicle detected during running, a shift control method for controlling a gear ratio of a continuously variable transmission mounted on the vehicle, wherein the running state of the vehicle is:
Estimating the gradient of the road surface on which the vehicle is traveling from the detection step of detecting the traveling resistance torque, the acceleration torque of the vehicle, and the output shaft torque of the continuously variable transmission, and the traveling state of the vehicle detected in the detection step. And a step of determining whether the road surface on which the vehicle is traveling is a slope when the gradient of the road surface estimated in the gradient estimation step is within a predetermined range, When it is determined that the road surface on which the vehicle is running is a slope, the slope of the road surface estimated in the slope estimation step is determined by the correspondence information that uniquely associates the target gear ratio of the continuously variable transmission with the slope of the road surface. And a control step of controlling the speed ratio of the continuously variable transmission so that the target speed ratio of the associated continuously variable transmission is achieved. The law provides.

According to the gear shift control device and the gear shift control method of the present invention, the target gear ratio of the continuously variable transmission can be determined in consideration of the gradient of the traveling path of the vehicle. Regardless, the vehicle can always maintain an optimum traveling state. That is, from the correspondence information in which the proper target gear ratio (or the correction value of the target gear ratio) is stored for each gradient of the traveling road, the target gear ratio (or the
When the vehicle is approaching a downhill, the target gear ratio corrected with the correction value determined according to the gradient of the road is acquired, and the gear ratio of the continuously variable transmission is controlled using this. Since the appropriate engine brake automatically operates, the safety of the vehicle can be ensured, and when the vehicle is approaching an uphill road, an appropriate driving force according to the slope of the road is transmitted. Therefore, it is possible to automatically exhibit excellent acceleration performance.

Therefore, even when the range cannot be switched in a timely manner when the vehicle runs on a downhill road with a steep slope, a proper engine brake automatically operates, so that even a driver unfamiliar with driving can drive downhill roads. It eliminates the frequent use of foot brakes when traveling. In other words, it is possible to expect an effect of preventing the wear of the brake caused by the driving skill of the driver.

Further, without newly installing a special sensor,
Since the gradient of the traveling path of the vehicle is estimated from the output of the detection means which is an existing sensor, the manufacturing cost of the vehicle does not increase even if the present CVT system is adopted. If the vehicle body weight is estimated by calculation or the like as described above, a vehicle weight sensor for detecting the vehicle body weight becomes unnecessary, and the manufacturing cost can be further reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings, as an example in which the embodiment is applied to a CVT system.

First, the hardware configuration of the control system of the CVT system according to this embodiment will be described with reference to FIG.

This CVT system is a continuously variable automatic transmission (hereinafter referred to as CVT) that transmits the output of the engine 1 to the wheels 8 through the engine 1, the drive shaft 7, the differential gear 6, and the propeller shaft 5. Call 2
And various sensors for detecting the traveling state of the vehicle, and a CVT control unit (hereinafter referred to as CVT ECU) 40 for controlling the CVT 2 according to the outputs of the various sensors.
And an engine control unit (hereinafter, referred to as an engine ECU) 30 that controls the engine 1 according to the outputs of the various sensors. The various sensors for detecting the running state of the vehicle in the present embodiment are C
The primary rotation sensor 29 that detects the rotation speed (hereinafter, referred to as the primary rotation speed) Np of the primary pulley (input side pulley) 19 of the VT2, and the rotation speed of the secondary pulley (output side pulley) 20 of the CVT2 (hereinafter, the secondary rotation speed). Secondary rotation sensor 26 for detecting Ns
And an air flow sensor 21 for detecting a flow rate Qa of air purified by the air cleaner 10 passing through the intake manifold 11, and a throttle opening degree for detecting an opening degree of the throttle valve 12 (hereinafter referred to as a throttle valve opening degree) TVO. A sensor 22, a crank angle sensor 23 for detecting a rotation speed Ne of a crankshaft of the engine 1 (hereinafter, referred to as an engine rotation speed) Ne, and an oxygen sensor for detecting an oxygen concentration M in exhaust gas discharged from the exhaust manifold 14. 28 and a vehicle weight sensor 27 attached to a suspension (not shown) for detecting the weight of the vehicle body.

CV controlled by the CVT ECU 40
T2 is composed of a torque converter 3 directly connected to a crankshaft of the engine 1 and a continuously variable transmission mechanism 4 directly connected to an output shaft of the torque converter 3. And
The torque converter 3 includes a pump 3a directly connected to a crankshaft of the engine 1, a turbine 3b directly connected to an output shaft of the torque converter 3, and a pump 3a so as to amplify the rotation of the pump 3a accompanying the rotation of the crankshaft of the engine 1. And a turbine 3b, and a stator 3c that controls the flow of oil that circulates between the turbine 3b and the turbine 3b. By rotating the turbine 3b with the oil that is pumped as the pump 3a rotates, The transmission torque of is amplified and transmitted to the output shaft. On the other hand, the continuously variable transmission mechanism 4 includes an input side pulley (hereinafter, referred to as a pulley) connected to the turbine 3b of the torque converter 3.
(Referred to as primary pulley) 19 and primary pulley 1
An output-side pulley (hereinafter, referred to as a secondary pulley) 20 connected with a metal belt (or chain) 9
The diameter of the primary pulley 19 changes according to the hydraulic pressure of the hydraulic circuit 17, and an arbitrary gear ratio can be achieved. The shift control valve 18 that controls the hydraulic pressure of the hydraulic circuit 17 is controlled by a shift operation command output unit 49 of the CVT ECU 40 described later.

ECU 30 for engine and ECU for CVT
As shown in FIG. 5, reference numeral 40 denotes a CPU 71 that executes various processes described below, and a ROM 7 that stores programs that define various processes described below and various characteristic maps described below.
2, and a RAM 73 for temporarily storing data such as the program and various characteristic maps at the time of executing various processes described later,
The input / output interface circuit 75 that controls the reception of outputs from various sensors and the output of control signals described below, and the LA and itself.
A LAN control circuit 76 that controls data transfer with another control unit connected by N and a bus 74 that connects these units to each other are provided.

This completes the description of the hardware configuration of the control system of this CVT system.

The main functional configuration of the engine ECU 30 will be briefly described below. The functional configuration mentioned here is a process realized by the data stored in the RAM 73 and the CPU 71.

The engine ECU 30 includes various control units that control the state of the engine in accordance with outputs from various sensors, for example, the opening of a fuel injection valve 15 that injects fuel into each cylinder of the engine and the intake manifold 11. Of the engine 1 by controlling the opening degree of the idle speed valve 13 provided in the engine 1 and the fuel injection control unit that optimizes the air-fuel ratio on the intake side of the engine, and the amount of air that bypasses the intake manifold 11. An idle rotation control unit that optimizes the idle rotation speed, an ignition timing control unit that optimizes the ignition timing of the engine 1 by controlling the ignition advance angle of the igniter, and the like are provided.

This is the end of the description of the main functional configuration of the engine ECU 30 control.

Hereinafter, the functional configuration of the CVT ECU 40, which is a feature of the CVT system, will be described in detail with reference to FIG. The functional configuration mentioned here is a process realized by the data stored in the RAM 73 and the CPU 71.

The CVT ECU 40 calculates the vehicle acceleration α according to the outputs of various sensors.
4, an acceleration torque calculation unit 45 that calculates the acceleration resistance torque of the vehicle using the vehicle acceleration α calculated by the vehicle speed differential calculation unit 44 and the outputs of various sensors, and the output axis of the CVT 2 using the outputs of the various sensors. Torque calculation unit 4 for calculating torque
2, a running resistance detection unit 43 that calculates the level ground resistance torque of the vehicle using the outputs of various sensors, and the slope of the running path of the vehicle using the outputs of the various sensors and the outputs of the above units 44, 45, 42, 43. CVT2 according to the gradient calculation unit 47 for calculating
Target speed ratio calculating section 48 for calculating the target speed ratio of the CVT 2 and the target speed ratio finally calculated by the target speed ratio calculating section 48 for controlling the speed ratio of the CVT 2
9 is provided. Hereinafter, these parts 42, 43, 44, 4
Each processing performed by 5, 47, 48 and 49 will be described.

First, the processing performed by the vehicle speed differential calculation section 44 will be described.

The vehicle speed differential calculation unit 44 calculates the acceleration α of the vehicle by converting the secondary rotation speed Ns detected by the secondary rotation sensor 26 into the wheel speed V and further differentiating it with respect to time.

Next, the processing performed by the acceleration torque calculation unit 45 will be described with reference to FIG.

The acceleration torque calculation unit 45 uses the acceleration α calculated by the vehicle speed differential calculation unit 44 in the blocks 84 and 45, the vehicle body weight W sequentially detected by the vehicle weight sensor 27, and the formula 1 as follows: The acceleration resistance torque Tα is calculated.

Tα = (W + Wr) · α · Rt / g (1) Here, Wr is a rotational inertia weight, Rt is a radius of a wheel (tire) during traveling, and g is a gravitational acceleration.

In the present embodiment, the acceleration resistance torque Tα is calculated using the acceleration α calculated by the above calculation, but the actual acceleration detected by the existing acceleration sensor (or the newly installed acceleration sensor). The acceleration resistance torque Tα may be calculated using the acceleration α.
Further, in the present embodiment, the acceleration resistance torque Tα is calculated using the vehicle body weight W which is sequentially detected by the vehicle weight sensor 27. However, in the case of an ordinary passenger vehicle, there is little change in the vehicle body weight during traveling. It is not always necessary to use the vehicle body weight W actually detected by the vehicle weight sensor 27 as described above. For example, the standard vehicle body weight of the vehicle (ride capacity of 2 persons) defined by the standard or the like may be used, or
It is also possible to estimate the vehicle body weight from the acceleration α calculated by the vehicle speed differential calculation unit 44 when the vehicle is traveling on a road surface with a constant gradient with a constant drive torque, and use this. In addition, even in the processes performed by the other units described below, if the vehicle body weight estimated by the method illustrated here is used, it is not necessary to mount a special sensor on the vehicle in order to detect the vehicle body weight. .

Next, referring to FIG. 3, the torque calculation unit 4
The processing performed by 2 will be described.

In block 56, the torque calculation unit 42 uses the primary rotation speed Np detected by the primary rotation sensor 29, the secondary rotation speed Ns detected by the secondary rotation sensor 26, and the mathematical expression 2 to calculate CVT2.
The speed reduction ratio ip of is calculated.

Ip = Np / Ns (2) Further, in block 82, the throttle opening Tvo detected by the throttle opening sensor 22 is detected by the characteristic map (Ne-Te characteristic diagram) stored in the RAM 73 in advance.
And the engine torque Te associated with the engine speed Ne detected by the crank angle sensor 23 are acquired. In addition, the characteristic map here (Ne-Te characteristic diagram)
Is the engine speed Ne for each throttle opening Tvo.
And the engine torque Te in a one-to-one correspondence.

On the other hand, in block 57, the engine speed Ne detected by the crank angle sensor 23 and the primary speed Np detected by the primary rotation sensor 29.
And Equation 3 are used to calculate the speed ratio e of the torque converter.

E = Np / Ne (3) Then, in block 52, the torque ratio t associated with the speed ratio e of the torque converter by the characteristic map (et characteristic diagram) stored in the RAM 73 in advance.
And the RAM is previously acquired in block 53.
From the characteristic map (e-Cp characteristic diagram) stored in 72, the pump capacity coefficient Cp of the torque converter corresponding to the speed ratio e of the torque converter is obtained.
Note that the characteristic map (e-t characteristic chart) here is correspondence information in which the speed ratio e and the torque ratio t of the torque converter are associated one-to-one, and the characteristic map (e-Cp characteristic chart). ) Is correspondence information in which the speed ratio e of the torque converter and the pump capacity coefficient Cp are associated one-to-one.

Then, in block 55, using the pump capacity coefficient Cp, the engine speed Ne detected by the crank angle sensor 23, and the equation 4, the input torque Tp 'to the torque converter (hereinafter referred to as pump (Called torque).

Tp '= Cp.Ne.Ne ... Formula 4 Then, in block 57, in accordance with the value of the speed ratio e of the torque converter calculated in block 57, the pump torque Tp' calculated in block 55 and the block Either one of the engine torque Te obtained at 82 is selected, and this is estimated as the normal pump torque Tt. As a specific example, when the speed ratio e of the torque converter is smaller than a predetermined value E (for example, 0.9),
The pump torque Tp 'calculated by the equation 4 is estimated as the normal pump torque Tp, not the engine torque Te including the torque loss due to an accessory such as an air conditioner, but the speed ratio e of the torque converter is a predetermined value E. When the value exceeds, the error included in the pump capacity coefficient Cp obtained from the characteristic map (e-Cp characteristic diagram) increases, and rather the error resulting from this exceeds the torque loss amount, so The engine torque Te obtained from the characteristic map (Ne-Te characteristic diagram) is estimated as the normal pump torque Tp, instead of the pump torque Tp ′ calculated in Step 4.

Then, in block 58, the torque ratio t obtained from the characteristic map (e-t characteristic diagram) in block 52 and the regular pump torque T estimated in block 57 are obtained.
The turbine torque Tt of the torque converter is calculated using p and Equation 5.

Tt = Tp · t (5) In the torque calculation unit 42, the torque converter turbine torque Tt calculated in the block 58 and the reduction ratio ip of the CVT 2 calculated in the block 56 are finally calculated in the blocks 59 and 83. And the equation 6 calculate the output shaft torque To of the CVT 2.

To = ip · ipf · Tt (6) Here, ipf is a CVT stored in the ROM 72 in advance.
2 is the final reduction ratio. In this embodiment, the output shaft torque To of the CVT 2 is calculated by the above calculation, but it is not always necessary to calculate the output shaft torque Td of the CVT 2 by the same processing. For example, a torque sensor may be attached to the drive shaft 7 to directly detect the actual output shaft torque To of the CVT 2.

Next, the processing performed by the running resistance detector 43 will be described.

The running resistance detector 43 detects the vehicle speed V proportional to the secondary rotation speed Ns detected by the secondary rotation sensor 26 and the vehicle weight W sequentially detected by the vehicle weight sensor 27.
And the equation 7 are used to calculate the level ground resistance torque Tr.

Tr = (μ · W + ka · V · V) · Rt ... Equation 7 Here, μ is a rolling frictional resistance coefficient, Rt is a radius of a wheel (tire) during traveling, and ka is an air resistance coefficient. Is.

In the present embodiment, the vehicle body weight W detected by the vehicle weight sensor 27 is used to calculate the level ground resistance torque Tr, but it is obtained by the method exemplified in the description of the acceleration torque calculation unit 45. The ground resistance torque Tr may be calculated using the vehicle body weight W.

Next, referring to FIG. 4, the gradient calculating section 47
The processing performed by will be described.

In the blocks 46a and 46b, the gradient calculating section 47 includes the acceleration resistance torque Tα calculated by the acceleration torque calculating section, the level running resistance torque Tr calculated by the running resistance calculating section 43, and the torque calculating section 42. The gradient torque Tθ is calculated by using the output shaft torque To of the CVT 2 calculated in (4) and Expression 8.

T.theta. = To-Tr-T.alpha .... Equation 8 Then, in block 86 and block 85, the gradient torque T.theta., The equation 9 and the approximation (.theta..apprxeq.sin.theta.) Established on the general road are used. Calculate the slope θ of the traveling path.

Θ≈sin θ = Tθ / (W · Rt) Equation 9 In the present embodiment, the vehicle body weight W detected by the vehicle weight sensor 27 is used to calculate the gradient θ of the vehicle running path. However, the vehicle body weight W obtained by the method exemplified in the description of the acceleration torque calculation unit 45 may be used to calculate the gradient θ of the traveling path of the vehicle.

Next, the processing performed by the target shift calculation section 48 will be described.

The target shift calculating section 48 determines that the gradient θ of the vehicle running path calculated by the gradient calculating section 47 is within a predetermined range (A <
When θ <B, for example, −0.03 ° <θ <0.03 °), the throttle opening sensor 22 is used in the shift schedule (see FIG. 9A) used in the shift control of a general CVT. Throttle valve opening detected by TV
After obtaining the target primary rotation speed Npt associated with O and the secondary rotation speed Ns detected by the secondary rotation sensor 26, the target rotation speed Npt is set to the secondary rotation speed Npt as the target gear ratio ipt.
The ratio of s (Ns / Npt) is calculated. The shift schedule here means the throttle opening Tvo and the vehicle speed V.
(Or secondary rotation speed Ns) and engine rotation speed Ne
(Or primary rotation speed Np) is associated information. According to the CVT 2, the gear ratio can be changed steplessly within the range surrounded by ABCDA of the shift schedule of FIG.

On the other hand, when the gradient θ of the vehicle running path calculated by the running resistance detecting section 43 is not within the above predetermined range (A ≧
θ or θ ≧ B, if corresponding to the above range, −
0.03 ° ≧ θ or θ ≧ 0.03), the RAM 7
In the characteristic map (θ-ipt characteristic diagram) stored in No. 3, the target gear ratio ipt associated with the gradient θ of the vehicle running path calculated by the running resistance detection unit 43 is acquired. Note that the characteristic map (θ-ipt characteristic diagram) referred to here is correspondence information in which the gradient θ of the traveling path of the vehicle and the target gear ratio ipt of the CVT 2 are associated with each other, as shown in FIG. 6A. Is.

Next, the processing performed by the shift operation command output section 49 will be described.

The gear shift operation command output unit 49 controls the hydraulic pressure of the hydraulic circuit 17 so that the actual gear ratio IPT of the CVT 2 becomes the target gear ratio ipt of the CVT 2 calculated by the target gear shift calculation unit 48 according to the above conditions. The operation amount of the shift control valve 18 for controlling the shift control valve 18 is determined, and the shift control valve 18 is driven. As a result of the hydraulic pressure supplied by the hydraulic circuit 17, C
The diameter of the primary pulley 20 of the VT2 changes so that the gear ratio of the CVT2 becomes the target gear ratio ipt.

This completes the description of the functional configuration of the CVT ECU 40.

Finally, referring to FIG. 7, this CVT ECU 4
The flow of the process repeatedly executed at a predetermined timing of 0 is summarized. However, here, the slope θ of the road surface on which the vehicle travels
The flow of control after the state where is calculated will be mainly described.

In step 100, the gradient calculator 47
When the vehicle has calculated the gradient θ of the traveling path of the vehicle according to the above-described processing, in step 101, the target shift calculation unit 48
The state of the vehicle traveling path is determined based on the gradient θ of the vehicle traveling path calculated by the gradient calculating unit 47. That is, when the gradient θ of the vehicle running road calculated by the gradient calculating unit 47 is within a predetermined range (A <θ <B), the running road of the vehicle is determined to be a normal road, and the process of step 103 is performed. When the gradient θ of the vehicle running path calculated by the gradient calculating unit 47 is out of the predetermined range (A ≧ θ or θ ≧ B), the vehicle running path is determined to be a slope and step 102 is executed. The process of is executed.
Incidentally, the processing of step 103 referred to here is as shown in FIG.
Is the above-described process of calculating the target gear ratio ipt of the CVT 2 using the target primary rotation speed Npt acquired from the gear shift schedule of step 102, and the process of step 102 is
Target gear ratio ipt obtained from target gear ratio correction value map
It is the above-mentioned processing for correcting the target speed ratio ipt of the CVT 2 obtained from the characteristic map (θ-ipt characteristic diagram) using the correction value ipc of. Then, in step 104, the gear shift operation command output unit 49 uses the target gear ratio ipt of the CVT 2 calculated by the target gear shift calculation unit 48 by any of the processes described above according to the process described above.
Drive.

As described above, according to the CVT system of the present embodiment, the CVT 2 is taken into consideration in consideration of the gradient of the traveling path of the vehicle.
Since the target gear ratio can be determined, the vehicle can always maintain an optimum traveling state regardless of the ups and downs of the traveling road. That is, the target gear ratio correction value map (see FIG.
By properly creating (b)), when the vehicle is approaching a downhill, appropriate engine braking is automatically applied to ensure vehicle safety, and the vehicle is uphill. When approaching, an appropriate driving force corresponding to the gradient of the traveling road is transmitted and excellent acceleration performance is exhibited.

Therefore, even when the range cannot be switched in a timely manner when traveling on a downhill road with a steep slope, an appropriate engine brake automatically operates, so that even a driver unfamiliar with driving can drive downhill roads. It eliminates the frequent use of foot brakes when traveling. In other words, it is possible to expect an effect of preventing the wear of the brake caused by the driving skill of the driver.

Further, without newly installing a special sensor,
Since the gradient of the traveling path of the vehicle is estimated from the output of the existing sensor, the manufacturing cost of the vehicle does not increase even if this CVT system is adopted. If the vehicle body weight is estimated by calculation or the like as described above, a vehicle weight sensor for detecting the vehicle body weight becomes unnecessary, and the manufacturing cost can be further reduced.

By the way, in the above-described processing of FIG. 7, when the vehicle is approaching the slope (the slope θ of the traveling road).
Where A ≧ θ or θ ≧ B), the characteristic map (θ
The target gear ratio ipt obtained from the (ipt characteristic diagram) is corrected by the correction value ipc obtained from the target gear ratio correction value map, but this need not always be the case, and for example, as shown in FIG. As described above, even when the vehicle is approaching a slope, the target speed ratio i of the CVT 2 is calculated using the target primary rotation speed Npt obtained from the shift schedule.
It is also possible to calculate pt and further correct this with the correction value ipc obtained from the target gear ratio correction value map. The target gear ratio correction value map referred to here is as shown in FIG.
As shown in (b), the gradient θ of the vehicle running path and the CVT2
Is the correspondence information in which the target gear ratio ipt and the correction value ipc of the target gear ratio ipt are associated. In this case, after the gradient calculating unit 47 calculates the gradient θ of the vehicle traveling path in step 200, the target shift calculating unit 48 obtains the target shift calculating schedule from the shift schedule when approaching a downhill in step 201. After calculating the target gear ratio ipt of the CVT 2 using the target primary rotation speed Npt, further step 204
Alternatively, in any of step 205, step 2
The correction value ipc used when correcting the target speed ratio ipt of the CVT 2 may be set at 06. That is, when it is determined in step 203 that the traveling road of the vehicle is a normal road based on the same determination criteria as in step 101 of FIG. 7, the correction value ipc is set to 0 in step 205, which is the opposite. If it is determined in step 203 that the vehicle is running on a slope, the correction value ipc should be set to the value obtained from the target gear ratio correction value map of FIG. 6B in step 204. Good. The correction referred to in the present embodiment is to add the correction value ipc of the target speed ratio ipt of CVT2 obtained from the target speed ratio correction value map shown in FIG. 6B to the target speed ratio ipt of CVT2. That is.

Even in this case, the target speed change ratio of the CVT 2 can be set according to the slope change of the running road, so that a comfortable running state can be maintained.

This is the end of the description of the embodiment according to the present invention. The embodiment according to the present invention is a CVT.
Not only the system but also an AT control system using a stepped transmission can be applied.

[0061]

According to the automatic transmission control device for a vehicle of the present invention, the target speed change ratio of the CVT can be determined in consideration of the gradient of the vehicle running road, so that it does not depend on the ups and downs of the running road. The vehicle can always maintain an optimum traveling state. That is, an appropriate target gear ratio (or correction value of the target gear ratio) is stored in advance for each gradient of the traveling road, and the target gear ratio (or the gradient of the traveling road) determined according to the gradient of the traveling road is stored. (Target gear ratio corrected with the correction value determined accordingly)
By using the CVT to control the shift of the CVT, when the vehicle is approaching a downhill, an appropriate engine brake automatically operates, so that the safety of the vehicle can be ensured and the vehicle can be uphill. When approaching, an appropriate driving force corresponding to the gradient of the traveling road is transmitted, so that excellent acceleration performance can be automatically exerted.

Therefore, even when the range cannot be switched in a timely manner when driving on a downhill road with a steep slope, a proper engine brake automatically operates, so that even a driver unfamiliar with driving can drive downhill roads. It eliminates the frequent use of foot brakes when traveling. In other words, it is possible to expect an effect of preventing the wear of the brake caused by the driving skill of the driver.

Further, without newly installing a special sensor,
Since the gradient of the traveling path of the vehicle is estimated from the output of the existing sensor, the manufacturing cost of the vehicle does not increase even if this CVT system is adopted. If the vehicle body weight is estimated by calculation or the like as described above, a vehicle weight sensor for detecting the vehicle body weight becomes unnecessary, and the manufacturing cost can be further reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a CVT system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a functional configuration of a CVT ECU 40 of FIG.

FIG. 3 is a block diagram for explaining a process of a torque calculation unit in FIG.

FIG. 4 is a block diagram for explaining the processing until the gradient of the vehicle running path is calculated by the CVT ECU 40 of FIG. 1.

FIG. 5 is a CVT ECU 40 and an engine EC of FIG.
It is a figure showing the basic composition of U30.

FIG. 6A is a characteristic map (θ-ip) used by the target shift calculation unit 48 to obtain a target gear ratio of CVT2.
(Characteristic diagram of t), and FIG.
6 is a target gear ratio correction value map used to obtain a target gear ratio correction value for VT2.

7 is a flowchart for explaining a flow of processing performed by the CVT ECU of FIG.

8 is a flowchart for explaining a flow of processing performed by the CVT ECU of FIG.

9A is a shift schedule for a normal mode, and FIG. 9B is a shift schedule for a sports mode.

[Explanation of symbols]

1 ... Engine, 2 ... Continuously variable transmission type automatic transmission (CV
T), 3 ... Torque converter, 3a ... Pump of torque converter 3, 3b ... Turbine of torque converter 3, 3
c ... Stator of torque converter 3, 4 ... Continuously variable transmission mechanism, 5 ... Propeller shaft, 6 ... Differential gear, 7 ... Drive shaft, 8 ... Wheels, 9 ... CVT2 belt, 10 ... Air cleaner, 11 ... Intake manifold,
12 ... Throttle valve, 13 ... Idle speed valve, 14
... Exhaust manifold, 15 ... Fuel injection valve, 17 ... Hydraulic circuit, 18 ... Shift control valve, 19 ... Primary pulley of CVT2, 20 ... Secondary pulley of CVT2, 21 ... Airflow sensor, 22 ... Throttle opening sensor, 23 ...
Crank angle sensor, 25 ... Primary rotation sensor, 26
... secondary rotation sensor, 27 ... vehicle weight sensor, 28 ... oxygen sensor, 30 ... engine control unit, 40
... CVT control unit, 42 ... Torque calculation unit,
43 ... Running resistance detection unit, 44 ... Vehicle speed differential calculation unit, 45 ...
Acceleration torque calculation unit, 47 ... Gradient calculation unit, 48 ... Target gear ratio calculation unit, 49 ... Gear change operation command output unit

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Claims (6)

[Claims] 1. A shift control device for controlling a gear ratio of a continuously variable transmission mounted on a vehicle according to a traveling state of the vehicle detected during traveling, wherein a target of the continuously variable transmission is provided. A storage unit that stores correspondence information that uniquely associates a gear ratio with a road gradient, and detects a running resistance torque, an acceleration torque of the vehicle, and an output shaft torque of the continuously variable transmission as a running state of the vehicle. Detecting means, gradient estimating means for estimating the gradient of the road surface on which the vehicle is traveling from the traveling state of the vehicle detected by the detecting means, and the gradient of the road surface estimated by the gradient estimating means is within a predetermined range. In this case, the determining means for determining that the road surface on which the vehicle is traveling is a slope, and the shift control device, when the determination means determines that the road surface on which the vehicle is traveling is a slope, Recorded in the storage means Controlling the gear ratio of the continuously variable transmission by using the target gear ratio of the continuously variable transmission that is associated with the gradient of the road surface estimated by the gradient estimating means based on the obtained correspondence information. Characteristic shift control device. 2. A shift control method for controlling a gear ratio of a continuously variable transmission mounted on a vehicle in accordance with a running state of the vehicle detected while the vehicle is running, wherein: From the traveling state of the vehicle detected in the detecting step of detecting the traveling resistance torque of the vehicle, the acceleration torque, and the output shaft torque of the continuously variable transmission,
A gradient estimating step of estimating a gradient of a road surface on which the vehicle is traveling, and determining that the road surface on which the vehicle is traveling is a slope when the gradient of the road surface estimated in the gradient estimating step is within a predetermined range. And a step of determining whether the road surface on which the vehicle is traveling is a slope in the judgment step, the correspondence information uniquely associating the target speed ratio of the continuously variable transmission with the slope of the road surface To be the target gear ratio of the continuously variable transmission that is associated with the road surface gradient estimated in the estimation step,
And a control step of controlling a gear ratio of the continuously variable transmission. 3. Using the detected running state of the vehicle,
A shift control device for controlling a gear ratio of a continuously variable transmission mounted on a vehicle according to a predetermined shift schedule, wherein a running resistance torque, an acceleration torque, and the continuously variable torque of the vehicle are set as a running state of the vehicle. Detecting means for detecting the output shaft torque of the variable speed transmission, storage means for holding correspondence information in which the correction amount of the target speed change ratio of the continuously variable transmission is uniquely associated with the slope of the road surface; From the traveling state of the vehicle, the gradient estimation means for estimating the gradient of the road surface on which the vehicle is traveling, and the correspondence information stored in the storage means are associated with the gradient of the road surface estimated by the gradient estimation means. Correction means for correcting the gear ratio of the continuously variable transmission determined according to the predetermined gear shift schedule by using the correction value of the target gear ratio of the continuously variable transmission. When the determination means determines that the road surface on which the vehicle is traveling is a slope, the speed change of the continuously variable transmission is performed so that the target speed ratio of the continuously variable transmission corrected by the correction means is achieved. A shift control device characterized by performing a ratio control. 4. While using the detected running state of the vehicle,
A shift control method for controlling a gear ratio of a continuously variable transmission mounted on a vehicle according to a predetermined shift schedule, wherein a running resistance torque, an acceleration torque, and a continuously variable torque of the vehicle are set as a running state of the vehicle. Detection step of detecting the output shaft torque of the transmission, and from the traveling state of the vehicle detected in the detection step,
The gradient estimation step of estimating the gradient of the road surface on which the vehicle is running, and the gradient estimation step estimated by the correspondence information in which the correction amount of the target speed change ratio of the continuously variable transmission is uniquely associated with the gradient of the road surface. A correction step of correcting the gear ratio of the continuously variable transmission determined according to the predetermined gear shift schedule by using the correction value of the target gear ratio of the continuously variable transmission associated with the slope of the road surface, When it is determined in the determination step that the road surface on which the vehicle is traveling is a slope, the speed change of the continuously variable transmission is performed so that the target speed ratio of the continuously variable transmission corrected in the correction step is achieved. And a control step for controlling the ratio. 5. The shift control device according to claim 1 or 3, wherein the detection means uses the vehicle speed and the vehicle body weight detected during traveling to accelerate the vehicle and to measure the running resistance torque of the vehicle. A shift control device, wherein: 6. The shift control device according to claim 1, 3 or 6, wherein said detecting means is an engine speed detected during traveling, an accelerator opening detected during traveling, and And a gear ratio of the continuously variable transmission that is detected by the shift control device, the output shaft torque of the continuously variable transmission being calculated.