JP2001090825A - Transmission input torque calculation device - Google Patents

Abstract

(57) [Problem] To provide an input torque calculation device for a transmission capable of calculating an input torque to a transmission appropriately and responsively. SOLUTION: The detection results (θacc, θacc,
Based on V), the target input shaft rotation speed (target Np) of the transmission is calculated by the target calculation means (S12). Then, based on the target input shaft rotation speed and the current input shaft rotation speed, the input shaft rotation speed change rate (dN
p / dt) (S14), and based on the predicted value of the input shaft rotational speed change rate, the inertia torque (Ti) input to the transmission is calculated.
Is calculated (S16).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input torque calculating device for a transmission, and more particularly, to an input torque calculating device for a transmission that uses the input torque as a parameter of a shift control.

[0002]

2. Description of the Related Art In recent years, automatic transmissions that transmit a driving force of an internal combustion engine (engine) to a drive wheel by changing the driving force according to a vehicle speed, an accelerator opening, and the like have been frequently used for vehicles. In such an automatic transmission, a high-pressure pump is operated by the driving force of an engine, and a high-pressure hydraulic pressure is applied by the high-pressure pump to engage and disengage a frictional engagement element (clutch) to switch gears. I have.

Further, recently, a continuously variable transmission (CVT) capable of continuously changing the speed has been put into practical use. In this CVT, a V-belt is wound around a primary pulley on the engine side and a secondary pulley on the wheel side. The primary and secondary pulleys are made effective by adjusting (narrowing or widening) the groove widths of the primary pulley and the secondary pulley by operating hydraulic pressure (line pressure or the like) from the high-pressure pump which also operates by the driving force of the engine. The diameter is changed to establish a desired rotational speed ratio, that is, a speed change ratio. In addition, in the CVT, in addition to such a speed ratio control, a line pressure control is performed so that a slip (slip) does not occur between the pulley and the V-belt. Thereby, a desired holding force is obtained between the pulley and the V-belt.

In such an automatic transmission in which the shift control and the line pressure control are performed using the operating oil pressure, when the input torque is larger than the hydraulic pressure, the clutch slips or the primary pulley or the secondary pulley is disengaged. V
There is a possibility that slippage may occur between belts, and there is a problem that the clutch, the pulley or the V-belt is damaged and the life is remarkably reduced. Therefore, normally, the operating oil pressure is adjusted to an appropriate value according to the input torque.

However, the input torque input to the automatic transmission includes not only the output torque of the engine but also the inertia torque (engine inertia torque) of the crankshaft and the drive shaft of the engine and the inertia of the input shaft of the automatic transmission. The torque (primary shaft inertia torque) is also included, and it is necessary to obtain the input torque by adding the engine inertia torque and the input shaft inertia torque to the engine output torque.

Therefore, particularly in a continuously variable transmission, a device having a structure in which an inertia torque is added to an engine output torque to properly obtain an input torque and a line pressure is set in accordance with the input torque is used. It is disclosed in Japanese Patent Publication No. 3-38517 and Japanese Patent Publication No. 4-40217.

[0007]

In the apparatus disclosed in the above publication, the inertia torque is obtained based on an actual change in the engine speed (such as ΔN).
It takes a certain amount of time to calculate the change in engine speed (detection time of change in rotation speed, computer calculation time)
Therefore, there is a response delay, and there is a problem that the inertia torque generated simultaneously with the change in the rotational speed cannot be obtained with good responsiveness. If the inertia torque cannot be obtained with good responsiveness in this way, the line pressure will be insufficient in time, for example, in a situation where the engine output increases and the engine rotation speed increases. In the case of CVT, the primary pulley or Slippage occurs due to insufficient clamping force between the secondary pulley and the V-belt, which also leads to deterioration of the V-belt and the like, which is not preferable.

Therefore, in the CVT, in order to secure the clamping force between the primary pulley or the secondary pulley and the V-belt to reliably prevent slippage, when the engine speed increases and the input torque changes to the increasing side, In view of the response delay, it has been considered to set the line pressure somewhat higher. That is, it is considered that a margin is provided for the line pressure.

However, setting the line pressure to a high value and providing a margin for the line pressure in this manner increases the engine speed more than necessary in order to increase the output of the high-pressure pump, which leads to deterioration of fuel efficiency and is therefore preferable. Not that. Further, if the line pressure is increased as expected, the clamping force may be increased more than necessary, and if the clamping force is too strong, the deterioration of the V-belt is accelerated, which is not preferable.

[0010] Even in the case of a stepped automatic transmission, problems similar to those in the case of the CVT described above occur with respect to the clutch for achieving the shift speed and the supply pressure for operating the clutch. SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and an object of the present invention is to provide an input torque calculating device for a transmission capable of calculating an input torque to the transmission properly and responsively. It is in.

[0011]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, a target is determined based on detection results of an acceleration instruction detecting means for detecting an acceleration instruction state to an internal combustion engine and a vehicle speed detecting means. The calculating means calculates a target input shaft rotation speed or a target gear ratio of the transmission. Then, the inertia torque calculating unit predicts the input shaft rotational speed change rate based on the target input shaft rotational speed or target gear ratio and the current input shaft rotational speed, and based on the predicted value of the input shaft rotational speed change rate. To calculate the inertia torque input to the transmission.

Here, the inertia torque input to the transmission depends on the rate of change of the input shaft rotation speed. The greater the rate of change of the input shaft rotation speed, the larger the value of the inertia torque input to the transmission. However, according to the above configuration, if the acceleration instruction detecting means knows the state of the acceleration instruction to the internal combustion engine and the vehicle speed detecting means knows the current vehicle speed, the speed change is performed before the input shaft rotation speed of the transmission actually changes. The input shaft rotation speed of the transmission corresponding to the target can be easily obtained based on a map or the like, and the input shaft rotation speed change rate can be easily predicted from the difference between the input shaft rotation speed and the current input shaft rotation speed. That is, based on the predicted input shaft rotational speed change rate, the inertia torque that is generated simultaneously with the change in the rotational speed and that is input to the transmission can be determined appropriately and with good responsiveness.

In a preferred embodiment, the transmission is a continuously variable transmission, and further includes an engine output torque calculating means for calculating an output torque of the internal combustion engine, and an output torque of the internal combustion engine calculated by the engine output torque calculating means. Transmission input torque calculation means for obtaining a transmission input torque to be input to the transmission based on the sum of the inertia torque, and control means for controlling a line pressure based on the transmission input torque obtained by the transmission input torque calculation means It is better to have.

In this case, the inertia torque which is generated simultaneously with the change in the rotational speed and is input to the transmission is determined with good responsiveness, so that the line pressure is controlled appropriately and without delay, and the line pressure is controlled as in the conventional case. There is no need to provide a margin for pressure. Therefore, the engine speed does not need to be increased more than necessary, and the deterioration of fuel efficiency is prevented. Further, since the clamping force is not increased more than necessary, the engine is rotated around the primary pulley and the secondary pulley. Also, the deterioration of the V belt can be suitably prevented.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Referring to FIG. 1, there is shown a schematic configuration diagram of an input torque calculation device for a transmission according to the present invention mounted on a vehicle, and the configuration of the input torque calculation device will be described below.

A continuously variable transmission (CVT) 10 is connected to a drive shaft 2 of an engine (internal combustion engine) 1 via a fluid coupling 4, a clutch 6, and an input shaft (primary shaft) 8.
The output shaft (secondary shaft) 30 of T10 has a gear 32,
A pair of wheels 38, 38 are connected via a differential gear unit 34 and an axle 36. Engine 1
Is, for example, a water-cooled gasoline engine. The fluid coupling 4 is a known one as a torque converter.
Switching between direct connection (lockup) and non-direct connection is possible according to the driving condition of the vehicle. The clutch 6 is a friction clutch, and can be disconnected when the engine 1 is in a neutral state, such as when starting.

Further, an oil pump 42 capable of generating high-pressure oil pressure is connected to the drive shaft 2 via a transmission member 40 such as a gear unit or a chain.
An oil passage 46 is connected to 2. That is, when the engine 1 is driven and the oil pump 42 operates, the oil pump 42 discharges the oil (operating oil) stored in the oil pan 44 to the high pressure hydraulic pressure, that is, the line pressure, to the oil passage 46.

The CVT 10 has a structure in which an endless V-belt 26 is wound around a primary pulley unit 12 and a secondary pulley unit 20, and the drive shaft 2 is connected to the primary pulley unit 12. More specifically, the primary pulley unit 12 and the secondary pulley unit 20 each have a fixed pulley 14 that is formed in a tapered shape such that the contact surface with the V-shaped both side surfaces of the V belt 26 is along the V-shaped both side surfaces. And a movable pulley 16, a fixed pulley 22, and a movable pulley 24. A hydraulic actuator 18 is provided on the primary movable pulley 16, and a hydraulic actuator 26 is provided on the secondary movable pulley 24. The movable pulley 16 and the movable pulley 24 are respectively operated by the hydraulic actuator 18 and the hydraulic actuator 26. When slid along the input shaft 8 and the output shaft 30, the groove width of the primary pulley unit 12 and the secondary pulley unit 20, that is, V
As a result, the effective diameter of the belt 26 changes, so that the speed ratio of the CVT 10 changes to perform the speed change.

More specifically, the oil passage 46 is connected to the hydraulic actuator 26 on the secondary side, and an electromagnetic type which is branched from the oil passage 46 and driven by a solenoid 51 is connected to the hydraulic actuator 18 on the primary side. The oil passage 48 in which the spool valve 50 is interposed is connected. In other words, the hydraulic pressure adjusted by the spool valve 50 for speed ratio control acts on the hydraulic actuator 18 on the primary side.

As shown in the figure, an electromagnetic spool valve 52 driven by a solenoid 53 is interposed in the oil passage 46. This spool valve 52 adjusts the magnitude of the line pressure supplied to the hydraulic actuator 26 on the secondary side, and the oil discharged from the spool valve 52 is sent to other parts requiring lubrication. Have been.

Since the CVT 10 is already known, a detailed description thereof will be omitted.
In the vicinity of the drive shaft 2 of the engine 1, an engine rotation sensor 6 for detecting the engine rotation speed Ne by the rotation of the drive shaft 2
In the vicinity of the primary pulley unit 12, a primary rotation sensor (input shaft rotation speed detecting means) 62 for detecting the rotation speed of the input shaft 8 of the CVT 10, that is, the primary rotation speed Np, is provided. In the vicinity of the gear 32 connected to the output shaft 30, the CVT 10
A vehicle speed sensor (vehicle speed detecting means) 64 for detecting the rotational speed of the secondary pulley unit 20, that is, the secondary rotational speed Ns, and detecting the vehicle speed V is provided. Further, a hydraulic pressure sensor 66 for detecting the hydraulic pressure in the oil passage 46 is provided near the hydraulic actuator 26 in the oil passage 46.

Electronic control unit (ECU) 70
Is a main control unit which comprises a central processing unit (CPU) and controls various controls of the vehicle such as the engine 1. The input side of the main control unit includes the above-described engine rotation sensor 60, primary rotation sensor 62, vehicle speed sensor 64, Various sensors such as a hydraulic pressure sensor 66 are connected, and an accelerator position sensor (APS, acceleration) for detecting an operation amount of an accelerator pedal 72 for adjusting the output of the engine 1, that is, an accelerator opening (acceleration instruction state) θacc. An instruction detecting means) 74 is connected.

On the other hand, the output side of the ECU 70 is connected to an electromagnetic throttle valve and an ignition coil (both not shown) of the engine 1 and the solenoids 51 and 53 of the electromagnetic spool valves 50 and 52. Hereinafter, the operation of the input torque calculating device for a transmission according to the present invention configured as described above, that is, the CVT line pressure control will be described.

Referring to FIG. 2, a control routine of the CVT line pressure control executed by the ECU 70 is shown in a flowchart, and will be described below with reference to the flowchart. The ECU 70 first determines in step S10 that the AP
The accelerator opening information θacc detected in S74, the vehicle speed information V detected by the vehicle speed sensor 64, and the primary rotation speed information (current input shaft rotation speed) Np detected by the primary rotation sensor 62 are read, respectively.

In step S12, step S
Accelerator opening information θacc and vehicle speed information V read in 10
Based on the accelerator opening information θacc and the vehicle speed information V, the primary rotational speed Np,
That is, the target Np (target input shaft rotation speed) is calculated (target calculation means). In the CVT 10, when the accelerator opening degree θacc indicating the acceleration instruction state changes, a shift is performed so that torque transmission is performed most efficiently without deteriorating fuel efficiency. That is, when the accelerator opening θacc is set, first, the secondary rotation speed N corresponding to the current vehicle speed V is set.
The gear ratio is set so that the output torque corresponding to the accelerator opening θacc can be transmitted most efficiently under s. Actually, the gear ratio is set in advance and mapped in accordance with the accelerator opening θacc and the vehicle speed V by an experiment or the like.
It is read from the map.

On the other hand, this speed ratio is determined by the secondary rotation speed N
s and the primary rotational speed Np, the vehicle speed V,
That is, when the gear ratio is set based on the secondary rotation speed Ns, the primary rotation speed Np, ie, the target Np
Will be determined. Therefore, the accelerator opening θac
c, the relationship between the vehicle speed V and the target Np is mapped in advance as a target Np map as shown in FIG. 3 similarly to the above-described speed ratio map, and in this case, the target Np is actually the target Np map. Read from.

In the next step S14, the deviation dNp (dNp) between the target Np obtained in this way and the actual primary rotation speed Np detected by the primary rotation sensor 62.
= Current Np-target Np) by calculation. Further, the deviation d with respect to the actual primary rotation speed Np
The time change rate of Np (input shaft rotation speed change rate) dNp / dt is predicted. Specifically, the change rate dNp / dt is obtained by dividing the deviation dNp by the time ta required until the primary rotation speed Np reaches the target Np. This time ta changes in accordance with the current primary rotational speed Np, and is set in advance by experiments or the like.

In step S16, an inertia torque Ti of the input shaft 8 including the drive shaft 2 and the primary pulley unit 12 as a part of the input torque of the CVT 10 is calculated (inertia torque calculating means). The inertia torque Ti is the sum of the engine inertia torque Tei of the engine system such as the drive shaft 2 and the fluid coupling 4 and the primary inertia torque Tpi of the primary pulley unit 12 and the input shaft 8 (Ti = Tei + Tpi), and the engine inertia torque Tei And the primary inertia torque Tpi are calculated from the following equations.

Engine inertia torque Tei = engine inertia coefficient · (2π / 60) · dNe / dt Primary inertia torque Tpi = primary shaft inertia coefficient
(2π / 60) · dNp / dt Here, the engine inertia coefficient is an inertia coefficient specific to an engine-system rotating member such as the drive shaft 2, and the primary shaft inertia coefficient is an inertia coefficient specific to the primary pulley unit 12 and the input shaft 8. It is a coefficient.

The engine inertia torque Tei is determined based on the time rate of change dNe / dt of the engine speed Ne, as shown in the above equation. When the CVT 10 is used even in a non-direct connection state, there is almost no difference in rotation between the pump side and the turbine side.
Therefore, it can be said that the drive shaft 2 and the input shaft 8 are substantially directly connected to each other. In this case, the change rate dNe / dt is set to the change rate dN
The operation is performed by substituting p / dt (dNe / dt = dNp / dt).
Thus, the engine inertia torque Tei together with the primary inertia torque Tpi can be easily calculated, that is, the inertia torque Ti can be easily obtained. Therefore, here, the change rate d of the primary rotational speed is
The primary inertia torque Tpi and the engine inertia torque Tei, that is, the inertia torque Ti are obtained based on Np / dt.

As described above, the primary rotation speed Np
Is changed in accordance with the current primary rotational speed Np. Therefore, the rate of change dNp / dt depends on the current primary rotational speed Np. That is, even if the deviation dNp is the same, the change rate dNp / dt increases as the current primary rotational speed Np increases.

In practice, the engine inertia coefficient, the primary shaft inertia coefficient, and the time ta are inherent values, and as shown in FIG. 4, the current primary rotational speed Np, the deviation dNp, and the inertia torque Ti are calculated. The relationship is set in advance as an experiment or the like and is mapped as an inertia torque map. The inertia torque Ti is based on the current primary rotational speed Np and the deviation dNp without calculating the rate of change dNp / dt one by one. It can be easily and immediately read from the torque map.

When the inertia torque Ti is obtained in this way, in step S18, the input torque to the CVT 10, that is, the CVT input torque TIN is calculated. That is,
As described above, the primary pulley unit 12 of the CVT 10 and the V belt 26 of the secondary pulley unit 20
Is determined by the input torque to the CVT 10, that is, the CVT input torque TIN, and the CVT input torque TIN is also affected by the inertia torque Ti. Therefore, here, the CVT input torque TIN is calculated from the following equation, including the inertia torque Ti (transmission input torque calculation means).

CVT input torque TIN = engine output torque Te + inertia torque Ti, where engine output torque Te
Can be easily obtained from the target average effective pressure calculated from the accelerator opening θacc and the engine rotation speed Ne, that is, the target Pe (engine output torque calculation means). Note that the engine output torque Te can also be obtained from the injection pulse width that determines the fuel injection amount.

When the CVT input torque TIN is obtained in this manner, in step S20, the CVT input torque TIN is determined.
IN is smaller than CVT allowable torque Ta (TIN <T
It is determined whether or not there is a). That is, in the CVT 10, in order to prevent the primary pulley unit 12, the secondary pulley unit 20, and the V-belt 26 from being damaged,
The clamping force of the V-belt 26 is limited, and the CVT input torque TIN obtained by calculation is equal to this limit value, that is, C
It is determined whether or not the VT allowable torque Ta has not been reached.
The determination result is true (Yes), and the CVT input torque TIN is C
If it is determined that the VT allowable torque Ta has not been reached, the process proceeds to step S22.

In step S22, the CVT input torque T
In accordance with IN, a line pressure, which is a source pressure of the operating hydraulic pressure supplied to the hydraulic actuator 18 and the hydraulic actuator 26 of the CVT 10, is adjusted (control means). That is, the line pressure is adjusted by adjusting the opening of the spool valve 52 by the solenoid 53. Note that the relationship between the CVT input torque TIN and an appropriate line pressure is set in advance, and in practice, the line pressure is adjusted while monitoring with the hydraulic pressure sensor 66.

On the other hand, if the determination result of step S20 is false (N
o), the CVT input torque TIN is equal to the CVT allowable torque Ta.
If it is determined as described above, the process proceeds to step S24, and C
In order to make the VT input torque TIN smaller than the CVT allowable torque Ta, correction control is performed so that the engine output torque Te is kept small. That is, the accelerator opening θacc is controlled to decrease. Thereby, the primary pulley unit 1
2. The breakage of the secondary pulley unit 20 and the V-belt 26 is prevented.

When step S24 is executed, the process proceeds to step S22 in the same manner as described above, and the line pressure is adjusted according to the CVT input torque TIN which is limited to be smaller than the CVT allowable torque Ta. As described above, according to the present invention, the change rate dNp of the primary rotation speed Np is obtained by calculating the deviation dNp, which is the rotation change amount of the primary rotation speed Np.
/ Dt is predicted, and based on the change rate dNp / dt, the inertia torque Ti is obtained by calculation before the primary rotation speed Np actually changes. Further, the input torque to the CVT 10, that is, the CVT input torque TIN is obtained based on the inertia torque Ti obtained by the calculation.

Therefore, according to the present invention, the inertia torque Ti can be obtained in a proper and responsive manner, so that it is possible to control the line pressure to an appropriate value without delay at the same time as the rotation change. V belt 2 based on line pressure
6, it is possible to adjust the holding force extremely appropriately without excess or shortage. As a result, it is not necessary to increase the engine rotational speed more than necessary by increasing the line pressure according to the expectation as in the related art and giving a margin to the line pressure, and it is possible to preferably prevent the fuel consumption from deteriorating. Since the clamping force of the V-belt 26 is not unnecessarily increased, the deterioration of the V-belt 26 can be suitably prevented.

In the above-described embodiment, the CVT in which the target primary rotational speed is set in the shift control is described as an example. However, the present invention is not limited to this method, and the target gear ratio is set in the shift control. It is also applicable to the CVT of the following method. In this case, a primary rotation speed corresponding to the target speed ratio is calculated based on the vehicle speed V and the target speed ratio, and the calculated target primary rotation speed is set to the target N in the above embodiment.
By substituting p, the inertia torque Ti can be calculated as in the above embodiment.

The input shaft rotation speed detecting means may calculate the current input shaft rotation speed based on the current gear ratio and the vehicle speed V. Further, in the above-described embodiment, an example in which the present invention is applied to a CVT is described. However, the present invention is not limited to this, and the present invention can be applied to a stepped automatic transmission.

[0042]

As described above in detail, according to the transmission input torque calculating apparatus of the first aspect of the present invention, before the input shaft rotation speed of the transmission is actually changed, the transmission map is used. The input shaft rotation speed of the transmission corresponding to the target can be easily obtained based on the target, and the input shaft rotation speed change rate can be easily predicted from the difference between the input shaft rotation speed and the current input shaft rotation speed. Therefore, the inertia torque which is generated simultaneously with the change in the rotation speed and is input to the transmission can be obtained appropriately and with good responsiveness.

Therefore, for example, when the transmission is a continuously variable transmission, the transmission input torque to be input to the transmission is obtained based on the sum of the output torque of the internal combustion engine and the inertia torque.
The line pressure is controlled based on the transmission input torque. The inertia torque which is generated simultaneously with the change in the rotational speed and is input to the transmission can be obtained with good responsiveness, so that the line pressure can be controlled properly and without delay. can do. Therefore, there is no need to provide a line pressure margin as in the past,
The engine speed does not need to be increased more than necessary, and deterioration of fuel efficiency can be prevented. Further, the holding force is not increased more than necessary, and the deterioration of the V-belt wrapped around the primary pulley and the secondary pulley can be suitably prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an input torque calculation device for a transmission according to the present invention mounted on a vehicle.

FIG. 2 is a flowchart showing a control routine of CVT line pressure control according to the present invention.

FIG. 3 is a target Np map showing a relationship between an accelerator opening θacc, a vehicle speed V, and a target Np.

FIG. 4 is an inertia torque map showing a relationship between a current primary rotational speed Np, a deviation dNp, and an inertia torque Ti.

[Explanation of symbols]

Reference Signs List 1 engine (internal combustion engine) 10 continuously variable transmission (CVT) 12 primary pulley unit 14 secondary pulley unit 18 hydraulic actuator 26 hydraulic actuator 42 oil pump 60 engine rotation sensor 62 primary rotation sensor (input shaft rotation speed detecting means) 64 vehicle speed sensor (Vehicle speed detecting means) 70 Electronic control unit (ECU) 74 Accelerator position sensor (APS, acceleration instruction detecting means)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Nobuaki Murakami, Inventor 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation F-term (reference) 3J052 AA09 AA17 AA20 CA21 CA31 GC13 GC23 GC44 GC46 HA11 KA01 LA01

Claims (1)

[Claims] 1. An input torque calculating device for a transmission mounted on a vehicle and transmitting a driving force of an internal combustion engine to a wheel by shifting the driving force, the input shaft rotation detecting a current input shaft rotation speed of the transmission. Speed detection means, acceleration instruction detection means for detecting an acceleration instruction state to the internal combustion engine, vehicle speed detection means for detecting a vehicle speed, and the transmission of the transmission based on the detection results of the acceleration instruction detection means and the vehicle speed detection means. Target calculating means for calculating a target input shaft rotational speed or a target gear ratio; a target input shaft rotational speed or a target gear ratio calculated by the target calculating means; and a current input shaft detected by the input shaft rotational speed detecting means. Inertia torque calculating means for predicting an input shaft rotation speed change rate based on the rotation speed and calculating an inertia torque input to the transmission based on a predicted value of the input shaft rotation speed change rate. An input torque calculation device for a transmission.