JPH02203066A - Control device for vehicle with automatic transmission - Google Patents

Abstract

PURPOSE:To improve durability of each friction element in an automatic transmission by decreasing a line pressure, adjusted by a line pressure adjusting means, after an engine is confirmed to execute a change of its generation torque in a speed change process of the automatic transmission. CONSTITUTION:When an automatic transmission is in its up or down shift, in principle while the action of speed change is performed, reduction of a speed change shock is contrive by changing ignition timing and generation torque of an engine. When execution is confirmed of changing the generation torque by a torque change confirming means from change of a turbine speed in a torque converter, a line pressure control means controls a line pressure adjusting means, consisting of a duty solenoid valve or the like, decreasing a line pressure. While in a speed change in coil time with the change not preferable of the generation torque, the speed change is controlled by a relatively high line pressure. In this way, durability can be ensured of a friction element in the automatic transmission.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a control device for a heavy vehicle equipped with an automatic transmission. Regarding what to change.

(Prior Art and its Problems) Vehicles equipped with automatic transmissions have a built-in problem of torque shock that accompanies gear shifting, that is, gear shift shock. That is, during the gear shifting process, the inertia of the rotating members of the automatic transmission is likely to have a temporary peak in the driving torque, and this temporal peak appears as a gear shifting shock. Therefore, in order to reduce the shift shock, it is sufficient to suppress the occurrence of the temporary peak of the driving torque described in (1).

Conventional - A common method for reducing shift shock is to engage a frictional element with the rotating members of the transmission to dissipate part of the energy held by the transmission as frictional heat, which transfers it to the drive torque side. Efforts are being made to reduce the rate of outflow.

However, now that engines are becoming more powerful,
! However, it is becoming increasingly difficult to balance the reliability of friction elements with gear shifting and traction. That is, the greater the output generated by the engine, the greater the amount of energy that must be dissipated as frictional heat, which poses a problem in the durability of the friction element.

Regarding the durability problem of this friction element, for example, Japanese Patent Application Laid-Open No. 59
Japanese Patent Publication No. 97350 discloses a technique for reducing shift shift and ivy by changing the torque itself generated by the engine as an auxiliary means. In other words, originally, the friction elements should be engaged slowly to suppress gear shift shock, but in high-output engines, problems arise with the durability of the friction elements, so by changing the engine output, the friction elements should be engaged slowly. This is an attempt to reduce the burden. This technique has the advantage that even if the friction element is operated slowly, its durability can be easily ensured.

However, depending on the operating state of the engine, it may be impossible or undesirable to change the torque generated by the engine. For example, if the torque generated by the engine is intentionally lowered by manipulating the fuel injection knee and ignition timing in order to reduce the shock of upshifting when the engine is cold, there is a risk that the engine will misfire. Alternatively, if the ignition timing is retarded to compensate for the torque generated by the engine when the exhaust temperature is high, the exhaust temperature will further rise due to so-called afterburning, and this will cause the reliability of the catalyst for exhaust gas purification. In addition, problems such as damage to the turbine blades occur when a turbocharger is attached.

If this engine control is not performed under such operating conditions because it is undesirable to change the engine torque, the negative phase of the frictional elements of the automatic transmission will increase, making it difficult to ensure this durability. It becomes difficult.

Therefore, the purpose of the present invention is to ensure the durability of the friction elements of the automatic transmission, even if the torque generated by the engine is not changed depending on the operating condition. An object of the present invention is to provide a control device for a vehicle.

(Means and effects for solving the problem) In order to achieve the above technical problem, the present invention includes a hydraulic automatic transmission, as shown in Fig. pJS1, and the automatic transmission The control device for a vehicle with an automatic transmission is designed to reduce shift shock by changing the torque generated by the engine during the gear shifting process, and the torque generated by the engine is actually changed during the gear shifting process of the automatic transmission. a torque change confirmation means for detecting that a change has been made; a line pressure adjustment means for adjusting line pressure in a hydraulic circuit of the automatic transmission; and a line pressure adjustment means for adjusting a line pressure in a hydraulic circuit of the automatic transmission; and a line pressure control means for reducing the line pressure after confirming that the line pressure is correct.

That is, the line pressure is lowered only after confirming that the engine torque has been changed.

With such a configuration, if, for example, the torque generated by the carrot is not changed in response to a gear shift when the engine is cold, the gear shift control will be performed at a relatively high line pressure.

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.

In FIG. 2, l is a cyclic reciprocating type o;
It is a toe-type engine body, and as is known, this engine body l is a so-called V-type engine in which the - bank 2 and the other back 3 are arranged in a V-shape 6. Bank 2 and the other bank 3 each have three cylinders 4.
It is said to be a 6-cylinder engine with a total of 6 air.

Each cylinder 4 has a combustion chamber 6 defined by a piston 5, and a spark plug (not shown) is disposed in the combustion chamber 6, and an intake boat 7 and an exhaust port 8 are opened [1]. Each boat 7.8 is opened and closed by an intake valve 9 or an exhaust valve 10 at known timings in synchronization with the engine output shaft (f2 omitted in the figure).

The intake ports 7 are opened at opposite sides of the - bank 2 and the other bank 3, and each intake port 7 is provided with a fuel injection valve 11.

The independent intake passages 12 connected to each intake port 7 are
Approximately 18 mm after extending away from the side of each bank 2.3
The passage has a shape that is reversed by 0 degrees. In other words, the central space 1 of the V bank sandwiched between the negative bank 2 and the other bank 3
3, long independent intake pipes 14 forming the independent intake passage 12 are arranged to intersect with each other. A surge tank 15 forming an intake expansion chamber is disposed in the V bank central space 13, and an L independent intake pipe 14 is connected to the surge tank 15.

In addition, in the intake passage 16 upstream of the tank 15 shown in E, from the upstream side to the downstream side, an air cleaner 17, an intake air temperature sensor 18 that detects the intake air temperature, and an air flow meter 19 that detects the intake air amount are installed in order. , throttle valve 20
A throttle position sensor 21 for detecting the opening degree of the throttle valve 20 is provided.

The internal space of the surge tank 15 is divided by a partition wall 22 into two chambers: an expansion chamber 15a for the bank 2 of - and an expansion chamber 15b for the other banks 3. Communication hole 2 between the enlarged chamber 15a and another enlarged chamber 15b
2a, and an on-off valve 24 that is opened and closed by a diaphragm 23 as an actuator is disposed in the communication hole 22a. This on-off valve 24 forms intake resonance tuning conditions according to the engine speed. Furthermore, the expansion chamber 15a mentioned above and the other expansion chamber 15b are as follows:
Bypass passage 2 that bypasses the throttle valve P20
5, the upstream upstream intake passage 16 of Iij is passed through,
A solenoid valve 26 is disposed in the bypass passage 25, and by adjusting the opening degree of the solenoid valve 26 to one position, the engine speed during idling operation can be adjusted.

On the other hand, in the exhaust passage 28 connected to the exhaust boat 8, an air-fuel ratio sensor 29,
Three-way catalyst 3O1 as an exhaust gas saving device A so-called catalyst sensor 31 is arranged to detect the temperature of this three-way catalyst 30. The air-fuel ratio sensor 29 is a so-called lean sensor that outputs a signal corresponding to the air-fuel ratio (oxygen surplus rate) of exhaust gas (there is already a sensor that outputs a signal approximately proportional to the air-fuel ratio). has been put into practical use).

The engine main body 1 has an automatic transmission 32 connected to its output shaft, and here the engine output shaft and the automatic transmission 4! ! A torque converter 33 is interposed between the torque converter 32 and the torque converter 33 . The automatic transmission 32 is composed of a multi-stage transmission consisting of a planetary gear mechanism and a hydraulic control circuit (see FIG. 4), and its gear shifting operation is controlled by a plurality of solenoid valves 34.
This is done by appropriately operating friction elements such as clutches and brakes based on the on/off combinations of the above.

As shown in FIG. 4, the multi-stage transmission has a forward clutch 80.2-4 brake 81.3-4 clutch 82 and a reverse clutch 83. ! 2 elements)'
By operating the r, the required gear stage is shifted. The hydraulic circuit for controlling these elements 80 to 83 schematically includes an oil pump 85, as shown in the figure, and a pressure line 8 from this oil pump 85.
The pressure of the hydraulic oil discharged into the valve 6 is adjusted by a pressure regulating valve 87 and guided to a select valve 88 . That is, line pressure adjustment by the pressure regulating valve 87 is performed by a pilot pressure regulating duty solenoid 89, and this pressure regulating valve 87
The line pressure adjusted by is supplied to each friction element 80 to 83 via a select valve 88. Accumulators 89-92 are provided on the lines L1-L4 connecting the select valve 88 and each of the diagonals 80-83, and solenoid valves 93 and 94 are provided on the lines L3 and L4. In addition, a solenoid valve 95 is also provided in the release line L5 of the 2-4 brake 81, for example, the SELEG L-valve 88
is in the D range position, solenoid valves 93 to 95
The required gear stage can be obtained by changing one combination of roN4 and rOFF.
6 is a timing valve. Each gear stage and each friction element 8
The operational relationship between the numbers 0 to 83 is shown in FIG.

In FIG. 2, reference numerals 40 and 41 indicate a control unit constituted by a microcomputer, and as is known, the CPU
, RAM, and ROM, the - control unit 40 is used for main control of the engine, etc., and the other control unit 41 is used for speed change control of the automatic transmission 32 (including lock-up control of the torque converter 33). has been done.

Signals from each of the sensors 18, 19, 21, 29, 31 are input manually to the L engine control unit 40, and signals from sensors 42 to 49 are also input to this main control unit 40. It looks like this. Above sensor 4
2 is a stop lamp switch attached to the brake pedal 51. Further, the sensor 44 is attached to the destroyer 54 to detect the crank angle, that is, the engine rotation speed, and the sensor 49 is to detect the engine cooling water temperature. And this main control unit 4
From 0, a control signal is output to the fuel injection valve 11, the solenoid valve 26, and the igniter 53. For example, when a predetermined ignition timing control is output from the control unit 40 to the igniter 53, the ignition coil 54 The secondary current is cut off and a high voltage is generated on the secondary side, and this high voltage on the secondary side is supplied to the spark plug (not shown) via the detripulator 52.

Signals from sensors 60 to 62 are input to the speed change control unit 41. The sensor 60 is the accelerator pedal 6
4 is a kick-down switch attached to sensor 6.
1 is an inhibitor switch attached to a select lever unit 65, and a sensor 62 is a torque converter 3
3 to detect the turbine rotation speed.

The main control unit 40 is configured to perform ignition timing control, air-fuel ratio control, idle rotation speed control, and intake inertia supercharging control. For example, air-fuel ratio control is the same as before.
The basic fuel injection amount is determined based on the intake air amount and the engine rotation speed, and this basic fuel injection amount is corrected according to the intake air temperature, engine cooling water temperature, acceleration/deceleration, etc., and the output from the air-fuel ratio sensor 29 is determined. This system performs feedback control to achieve the desired air-fuel ratio while receiving the In addition, the intake inertial supercharging control is performed using the on-off valve 24 according to the engine speed.
By opening and closing, resonance tuning conditions are created between the low-speed operating range and the high-speed operating range. That is, the diaphragm 23 as an actuator of the closing valve 24
The intake negative pressure is used as its operating source, and by controlling a renoid valve (not shown) attached to the air guide pipe 63, the on-off valve 22 is closed in the low rotation range, and closed in the high rotation range. The on-off valve 2z is opened. Other ignition timing control and idle rotation speed control are basically the same as conventional ones, so a detailed explanation thereof will be omitted, and only the parts related to the present invention will be described later.

Basically, the shift control unit 41 selects a predetermined shift stage based on the control map shown in FIG. 3 in accordance with the throttle opening and medium speed. In addition, in the same figure, solid lines u1 to u3 indicate the shift change line in the case of upshift, and broken lines d1 to d3 indicate the shift change line in the case of downshift.More specifically, the upshift change line u1 is It is for shifting from L speed to 2nd speed, and U
2 is for shifting from 2nd speed to 3rd speed, and U3 is for shifting from 3rd speed to 4th speed. The downshift switching line d1 is for shifting from 2nd speed to 1st speed, d2 is for shifting from 3rd speed to 2nd speed, and d3 is for shifting from 4th speed to 3rd speed.

In addition, in 1- above shift or town shift, the ignition timing is basically changed during the gear shifting operation to change the generated torque of the engine, thereby reducing gear shifting shock. is being used. still,
In this embodiment, a...

The ignition timing is changed only during gearshifting, and therefore, during the gearshifting process, the ignition timing is retarded by a predetermined amount to reduce the torque generated by the engine.
The line pressure of the automatic transmission a32 is reduced. However, when the engine is in a specific operating state in which it is not desirable to change the ignition timing, control to increase the line pressure of the automatic transmission 32 is performed instead of the retard control.

Based on the above-mentioned premise, engine control and shift control (line pressure adjustment control) accompanying a shift will be explained in detail based on the flowcharts shown in FIGS. 6 and 7.

FIG. 6 shows the retard control of the ignition timing accompanying the speed change, which is part of the engine control.

First, in step Sl, it is determined whether or not a gear shift is being executed. In other words, it is determined whether or not the switching of the friction elements 80 to 82 in the automatic transmission a32 is actually started and ends. Here, the shift start point (indicated by Pl in Figure 8) and the shift end point (P2 in Figure 8)
As shown in FIG. 8, since a large change appears in the turbine rotation speed of the torque converter 33, the shift start point Pt is determined by the rate of change in the turbine rotation speed.
, the end point P2 is detected.

Since this specific detection method is conventionally known, further explanation will be omitted.

[-When it is determined in step S1 that the shift has started, the process proceeds to step S2, where it is confirmed whether or not the detection of the start of the shift is correct.
Proceeding to step 3, on the condition that the engine is sufficiently warmed up, retard control is performed to retard the ignition timing by a predetermined amount in step S4, and in addition to this, in step S5, a retardation confirmation signal is generated. is sent from the main control unit 40 to the transmission control unit 41.

FIG. 7 shows the contents of the speed change control, particularly the contents of the line pressure adjustment control.

In step SIO, the vehicle speed and throttle opening are manually adjusted, and in the next step Sll, a gear position corresponding to the current driving condition is selected from the map shown in FIG. control is performed. Then, in the next step S13, it is determined whether or not there is the above-mentioned retard angle confirmation signal.
If it is determined that the line pressure is present, the process proceeds to step $14, where the duty solenoid 89 for regulating the pilot pressure iA is controlled so that the line pressure is increased. In step S13, when it is determined that the retardation confirmation signal is "I!lij", the process proceeds to step S15, where the duty solenoid 89 is controlled so that the line pressure is lowered.

FIG. 8 shows these controls over time.

With the above control, when the engine is warmed up, the ignition timing is retarded as the gear is changed, and the line pressure of the automatic transmission 32 is Since control is performed to lower f, the shift shock is reduced while improving the reliability of the friction elements 80 to 82. In other words, in cold conditions when no retard control is performed, the retard confirmation signal is not output, so it is possible to reliably prevent the line pressure from decreasing at such times. It is possible to prevent the line pressure from being uneasily lowered and imposing a stress burden on the friction elements.

In addition, Fig. 9 shows the relationship between the level of line pressure and the shift line - r time. tl represents the time required for shifting when the pilot pressure is high, that is, when the line pressure is high, and t2 represents the time required for shifting when the pilot pressure is high. This represents the time required for shifting when the pressure is low, that is, when the line pressure is low.

(Effects of the Invention) As is clear from the following explanation, according to the present invention, the line pressure of the automatic transmission is reduced only when there is engine control for gear shifting. In an operating state in which accompanying engine control is not performed, the gear shifting operation is performed with a high line pressure, so that the durability of the friction elements of the two-way automatic transmission can be ensured.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention. FIG. 2 is an overall configuration diagram of the embodiment. Figure 3 is a map for speed change control. Figure 4 is a schematic diagram of the hydraulic control circuit of the automatic transmission. FIG. 5 is an operational relationship diagram showing the relationship between the action of the friction element and the gear position. FIGS. 6 and 7 are flowcharts showing control details. FIG. 8 is a timing chart showing control details over time. FIG. 9 is an explanatory diagram of the operation of the embodiment. 80 to 83: Engine: Automatic transmission: Engine control i unit: Shift control unit: Engine cooling water temperature sensor: Igniter: Turbine rotation speed sensor: Friction element: Pressure regulating valve Figure 89: Duty solenoid for pilot pressure regulation Vehicle speed (km) Figure 7 Figure 6

Claims (1)

[Claims] (1) A control device for a vehicle with an automatic transmission, which is equipped with a hydraulic automatic transmission, and which changes the torque generated by the engine to reduce shift shock when the automatic transmission is in the process of shifting, comprising: a torque change confirmation means for detecting that the torque generated by the engine has actually been changed during the shift process of the automatic transmission; a line pressure adjustment means for adjusting the line pressure in the hydraulic circuit of the automatic transmission; A vehicle with an automatic transmission, comprising: line pressure control means that reduces the line pressure after confirming that a change in the torque generated by the engine has been executed during a shift process of the automatic transmission. control device.