JP2001304385A - Line-pressure controller for belt-type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a line-pressure controller for a belt-type continuously variable transmission, capable of accurately calculating an engine torque which is actually inputted in a CVT for constantly realizing proper line pressure control. SOLUTION: In this line-pressure controller, an output torque Te of an engine is detected (map A), a refrigerant pressure Pac of a compressor for an air conditioner is detected as a parameter value changing in accordance with loaded degrees of auxiliary machines for determining a driving loss ΔT, due to the auxiliary machines from this refrigerant pressure Pac (map B), and the engine torque Te is corrected by the driving loss ΔT for calculating a corrected engine torque Tcvt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line pressure control device for controlling a line pressure acting on a pulley of a belt type continuously variable transmission (hereinafter referred to as "CVT") to adjust a clamping force of the pulley to the belt. It is.

[0002]

[Related Background Art] CVT widely practiced in recent years
Supplies hydraulic oil from an oil pump to a primary pulley and a secondary pulley connected by a belt, adjusts the effective diameter of both pulleys, and applies driving force from the engine to a driving wheel side with a gear ratio according to a traveling state of the vehicle. It is configured to transmit to. In order to prevent belt slip caused by power transmission, both pulleys always receive a line pressure from an oil pump to apply a clamping force to the belt. In order to prevent slippage, it is necessary to set a high line pressure to apply a strong clamping force to the belt.However, an increase in the line pressure not only leads to a drive loss of the engine driving the oil pump but also causes excessive clamping. Since the force causes a reduction in the durability of the belt, it is desirable to adjust the pinching force by controlling the line pressure according to the transmission torque between the two pulleys (in other words, the torque input to the CVT). .

[0003] Therefore, for example, in a line pressure control device described in Japanese Patent Publication No. 5-48386, an engine torque is calculated from a throttle opening and an engine rotation speed, and the line pressure is controlled in accordance with the engine torque. I have. Further, when an air conditioner (hereinafter, referred to as an air conditioner) mounted on a vehicle is operated, the torque input to the CVT is reduced by the drive loss of the compressor. By subtracting the torque from the torque, the holding force is reduced with a decrease in the line pressure to prevent unnecessary drive loss of the oil pump.

[0004]

As is well known, since the capacity of a compressor during air conditioner operation is variably controlled based on the temperature in the passenger compartment, the driving loss of the compressor greatly changes according to the control state. . However,
In the line pressure control device described in the above publication, the engine torque is simply corrected by a predetermined value uniquely set as the drive loss according to the operation and stop of the compressor, so that the actual drive loss and In some cases, far-off corrections were applied. As a result, improper control of the line pressure is performed, and there is a possibility that the drive loss of the oil pump is increased due to an excessive belt clamping force, and conversely, a belt slip is caused due to an excessively small clamping force.

SUMMARY OF THE INVENTION It is an object of the present invention to accurately calculate the engine torque actually input to the CVT, always realize proper line pressure control, and prevent various adverse effects due to inappropriate belt clamping force. It is an object of the present invention to provide a line pressure control device for a belt-type continuously variable transmission that can prevent such a problem.

[0006]

According to a first aspect of the present invention, there is provided a belt-type continuously variable transmission connected to an engine and capable of continuously changing a gear ratio. An engine torque detecting means for detecting, a load degree detecting means for detecting a parameter value which changes according to a load degree of the auxiliary equipment driven by the engine, and an output value from the engine torque detecting means to an output value from the load degree detecting means. And a target line pressure setting means for setting a target value of the line pressure capable of adjusting the belt clamping force in accordance with the corrected engine torque corrected by the correction means. Line pressure control means for controlling the line pressure.

Therefore, the engine torque detected by the engine torque detecting means is corrected by the correcting means based on the parameter value detected by the load degree detecting means, and the target line pressure setting means is set in accordance with the corrected engine torque. The actual line pressure is controlled by the line pressure control means based on the target line pressure thus set. Then, since the engine torque is corrected by the parameter value correlated with the degree of load of the auxiliary components of the engine, it is possible to reflect the net drive loss according to the operating state of the auxiliary devices in the corrected engine torque. It becomes possible.

According to the second aspect of the present invention, the engine torque detecting means outputs a positive detection value when the driving wheels are driven by the engine, and outputs a negative value when the driving wheels are driving the engine. Output detection value,
The correction means is configured to correct the output value of the engine torque detection means by subtracting the output value of the load degree detection means from the output value, and to set a value corresponding to the absolute value as the corrected engine torque.

Therefore, when the driving wheels are driven by the engine, for example, when the vehicle is driven at a constant speed or during acceleration, the driving loss caused by the auxiliary components acts in the direction of reducing the engine torque. Since the parameter value of the load degree detecting means is subtracted from the value of the engine torque, the absolute value of the corrected engine torque is corrected to be reduced in accordance with the actual direction of the drive loss. Also, for example, when the engine side is driven by driving wheels such as during deceleration,
The drive loss caused by the accessories acts in the direction of increasing the engine torque. At this time, since the parameter value of the load degree detecting means is subtracted from the negative engine torque, the action direction of the actual drive loss , The absolute value of the input torque is corrected to increase.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a line pressure control device for a belt-type continuously variable transmission according to the present invention will be described below. As shown in the overall configuration diagram of FIG. 1, a compressor 3 of an air conditioner is connected to an engine 1 mounted on a vehicle via a belt 2, and the compressor 3 is connected to the engine 1 via an electromagnetic clutch 3a when the air conditioner operates. The cooling and the dehumidification using the refrigeration cycle are performed by compressing the refrigerant circulating in the piping (not shown) by being rotationally driven.
In addition, an alternator, a power steering pump, and the like are also connected to the engine 1 and are each driven to rotate.

The engine 1 is combined with a CVT 4 as a transmission. Engine 1 crankshaft 1a
Is connected to a primary pulley 7 via a torque converter 5 of the CVT 4 and a clutch 6 for switching between forward and backward movement (detailed description is omitted). The primary pulley 7 is connected to a secondary pulley 9 by an endless belt 8, and the secondary pulley 9 is connected to a driving wheel 12 via a secondary reduction mechanism 10 and a differential gear 11. C
The oil pump 14 of the VT 4 is rotationally driven by the crankshaft 1a of the engine 1 via a transmission mechanism (not shown), and the hydraulic oil is adjusted as a line pressure by a hydraulic control device 13 as a line pressure control means. In accordance with the switching of the circuit 13, the hydraulic fluid is supplied to the hydraulic actuators 7a, 9a of the primary pulley 7 and the secondary pulley 9.

The effective diameters of both pulleys 7, 9 are changed by hydraulic actuators 7a, 9a according to the supply state of hydraulic oil from hydraulic control device 13, and the driving force of engine 1 is reduced according to the speed ratio. The power is transmitted to the drive wheels 12.
Further, in response to the line pressure adjusted by the hydraulic control circuit 13 as described above, the pulleys 7 and 9 always apply a clamping force to the belt 8 to prevent slippage.

On the other hand, an input / output device (not shown) is provided in the vehicle interior.
An ECU (electronic control unit) 2 including a storage device (ROM, RAM, etc.) for storing control programs, control maps, and the like, a central processing unit (CPU), a timer counter, and the like.
The ECU 21 is provided with the engine 1
And CVT4 are controlled comprehensively. On the input side of the ECU 21, an opening TP of a throttle valve of the engine 1 is provided.
The throttle sensor 22 detects S, the engine speed sensor 23 detects the rotation speed Ne of the engine 1, the primary rotation speed sensor 24 detects the rotation speed Np of the primary pulley 7, and the rotation speed Ns of the secondary pulley 9.
, A refrigerant pressure sensor 26 as load degree detecting means for detecting the refrigerant pressure Pac of the compressor 3, and various sensors are connected, and information on their detection is input. .

The refrigerant pressure sensor 26 is installed, for example, on the discharge side (high pressure side) of the compressor 3 and detects the pressure Pac of the refrigerant discharged from the compressor 3. Also EC
The output side of U21 is connected to an ignition igniter, a fuel injection valve and the like (not shown) of the engine 1 and a CVT.
Four hydraulic control devices 13 are connected. And EC
U21 performs the ignition timing control and the fuel injection control of the engine 1 based on the information from these sensors and switches, and also executes the speed ratio control and the line pressure control of the CVT 4. Hereinafter, the control of the CVT 4 will be described in detail.

First, the gear ratio control will be described. A target gear ratio is set based on the vehicle speed V calculated from the secondary rotational speed Ns and the throttle opening TPS, and the actual gear ratio R is set.
The hydraulic control device 13 is controlled so that (the primary rotation speed Np / the secondary rotation speed Ns) becomes the target gear ratio. Also, regarding the line pressure control, the target line pressure Plin is determined from the absolute value of the input torque Tcvt of the CVT 4 and the actual speed ratio R.
e is set (target line pressure setting means), and the hydraulic control device 32 is controlled so that the actual line pressure becomes the target line pressure Pline (line pressure control means). Input torque Tcv of CVT4
Although t is obtained by correcting the driving loss ΔT of the compressor 3 of the air conditioner based on the engine torque Te, in the present embodiment, a specific driving loss ΔT is calculated from the refrigerant pressure Pac of the compressor 3 and the calculation result is expressed by the engine. Torque T
Applied to the correction of e.

Hereinafter, the procedure for setting the target line pressure Pline will be described in detail with reference to FIG.
The engine torque Te is calculated from the PS and the engine rotation speed Ne (engine torque calculation means). This calculation process is performed according to the map A set from the specifications of the engine 1 and the like. For example, when the driving wheel 12 side is driven by the engine 1 via the CVT 4 such as at the time of running at a constant speed or during acceleration, the engine torque Te is calculated as a positive value. When the engine 1 is driven via the CVT 4 by the drive wheels 12 rotating by the inertia of the vehicle, the engine torque Te is calculated as a negative value.

On the other hand, a drive loss ΔT is calculated from the refrigerant pressure Pac detected by the refrigerant pressure sensor 26 and the engine speed Ne (load degree detecting means). This calculation process is performed according to the map B set based on the specifications of the compressor 3 and the like, and the higher the refrigerant pressure Pac, the larger the drive loss ΔT is calculated. Then, the drive loss ΔT obtained in this way is subtracted from the engine torque Te and subjected to an absolute value processing, and the input torque Tcvt of the CVT 4 is calculated (correction means). When the input torque Tcvt of the CVT 4 is calculated, a correction according to the drive loss of the alternator, the power steering pump, and the like is also performed. This correction process is well known, and when any of the accessories operates, a value preset for the accessory is subtracted from the engine torque Te.

Here, when the drive wheels 12 are driven by the engine 1, the drive loss ΔT of the compressor 3 acts in the direction of reducing the input torque of the CVT 4 to the primary pulley 7 side. Since the drive loss ΔT is subtracted from the value of the engine torque Te,
The input torque T corresponding to the working direction of the actual drive loss ΔT
The absolute value of cvt will be corrected to decrease. Also, when the engine 1 is driven by the drive wheels 12, the drive loss ΔT of the compressor 3 acts in a direction to increase the input torque of the CVT 4 to the secondary pulley 9 (the driving of the compressor 3 in addition to the engine 1 is also performed). Cost)
At this time, the drive loss ΔT is subtracted from the negative value of the engine torque Te, so that the absolute value of the input torque Tcvt is corrected to increase in accordance with the actual action direction of the drive loss ΔT.

In the line pressure control device of this embodiment, when calculating the input torque Tcvt of the CVT 4, a specific drive loss ΔT obtained from the refrigerant pressure Pac of the compressor 3 is used.
Has been applied. That is, the drive loss ΔT of the compressor 3
Varies according to the capacity control of the compressor 3 based on the vehicle interior temperature and the like. However, since the drive loss ΔT is the work done to compress the refrigerant, the refrigerant pressure Pac and the rotational speed of the compressor (engine (Proportional to the rotational speed Ne), and the net drive loss ΔT in accordance with the operating state of the compressor 3 is applied to the calculation of the input torque Tcvt of the CVT 4.
4, the input torque Tcvt can be accurately calculated, and appropriate line pressure control can always be realized.

Therefore, for example, at the time of constant speed running or acceleration, the input torque Tcvt is accurately reduced and corrected by the obtained drive loss ΔT, so that the belt clamping force is reduced to the minimum necessary. In addition, it is possible to prevent a drive loss of the oil pump 14 due to an unnecessary increase in the line pressure Pline, thereby achieving an improvement in fuel efficiency. In addition, at the time of deceleration, for example, the input torque Tcvt is appropriately increased and corrected by the obtained drive loss ΔT, so that the belt clamping force is increased to a value that allows for the drive loss of the compressor 3, and as a result, the belt slip is reduced. Can be prevented beforehand.

Although the embodiment has been described above, aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the drive loss ΔT is obtained from the refrigerant pressure Pac of the compressor 3 of the air conditioner, and the drive loss ΔT is applied to the correction of the engine torque Te. It is not limited to three. Therefore, for example, the drive loss of the alternator or the power steering pump is not set as a predetermined value as in the above embodiment, and the drive loss of the alternator is determined by the charging current, and the drive loss of the power steering pump is determined by the driver. From the steering, a net drive loss according to each driving state may be obtained.

[0022]

As described above, according to the line pressure control apparatus for a belt-type continuously variable transmission according to the first aspect of the present invention, the engine torque is corrected by the parameter value that changes depending on the load of the auxiliary equipment. Therefore, it is possible to reflect the net drive loss in accordance with the operating state of the accessories in the corrected engine torque, and always realize appropriate line pressure control based on the corrected engine torque.

According to the line pressure control apparatus for a belt-type continuously variable transmission according to the second aspect of the present invention, the correction processing is performed in accordance with the direction in which the drive loss of the auxiliary equipment acts on the engine torque. When the drive loss acts in the direction of reducing the engine torque, the belt clamping force is reduced to prevent the drive loss of the oil pump due to an unnecessary increase in the line pressure, and the drive loss acts in the direction of increasing the engine torque. In this case, the belt holding force can be increased to prevent the belt slip.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating a line pressure control device of a belt-type continuously variable transmission according to an embodiment.

FIG. 2 is an explanatory diagram showing a procedure for setting a target line pressure.

[Explanation of symbols]

13 hydraulic control device (line pressure control means) 21 ECU (engine torque detection means, load degree detection means, correction means, target line pressure setting means, line pressure control means) 26 refrigerant pressure sensor (load degree detection means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kaoru Kondo 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Toru Hashimoto 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi F term (reference) 3J552 MA07 MA12 MA26 NA01 NB01 PA12 PA51 PA63 QA14C QC09 RB14 RB15 RB18 SA36 SA52 TA01 VA18W VA18Y VA32Z VA37Z VA53Y VA74Y VC01Z VC02W VC03Z VC10W

Claims (2)

[Claims] 1. A belt-type continuously variable transmission connected to an engine and capable of changing a gear ratio steplessly, an engine torque detecting means for detecting an output torque of the engine, and accessories driven by the engine. Load degree detecting means for detecting a parameter value which changes according to the load degree, correction means for correcting an output value from the engine torque detecting means with an output value from the load degree detecting means, and correction by the correction means. Target line pressure setting means for setting a target value of the line pressure capable of adjusting the clamping force of the belt according to the corrected engine torque; and line pressure control means for controlling the line pressure so as to be the target line pressure. A line pressure control device for a belt-type continuously variable transmission, comprising: 2. The engine torque detecting means outputs a positive detection value when a driving wheel side is driven by an engine, and outputs a negative detection value when the engine side is driven by a driving wheel. 2. The correction means according to claim 1, wherein the correction means corrects by subtracting an output value of the load degree detection means from an output value of the engine torque detection means, and sets a value corresponding to the absolute value as a corrected engine torque.
4. The line pressure control device for a belt-type continuously variable transmission according to <1>.