JPS62246649A - Automatic transmission for automobile - Google Patents

Abstract

PURPOSE:To enhance moving performance under an atmospheric depression, by providing a shift schedule adjusting means which varies speed change points based on detected signals of atmospheric pressure. CONSTITUTION:The first data table which stores an ordinary shift schedule and the second data table storing a shift schedule for an atmospheric depression of which speed change points are set up for a higher car speed side are read in an electronic controller 800. The electronic controller 800 is connected with respective sensors of a car speed sensor 802, an atmospheric pressure detecting sensor 801, an accel sensor 803 and the like as well as respective electromagnetic valves, so that the electromagnetic valves are electrically controlled being based on the output signals of the respective sensors. In case that atmospheric pressure detected by the atmospheric pressure sensor 801 is a depression, the second data table is selected and the speed change points were set up for the higher speed side, so that the on-off control of the electromagnetic valves is carried out at a higher speed side. Therefore, an engine is operated on a high-powered condition, so that travelling performance is not deteriorated.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to automatic transmissions for automobiles, and more specifically, to changing the shift schedule according to atmospheric pressure to improve driving performance under low pressure conditions such as when driving at high altitudes. Related to automatic transmissions.

(Prior Art) Conventional automatic transmissions for automobiles include, for example, Automotive Engineering Book Shu, Volume 9, "Power Transmission Device" (November 2, 1980).
The one described on pages 238 to 251 of the publication (published by Sankaido) is known. The automatic transmission of this automobile is constructed by combining a torque converter and a speed change gear mechanism in which components are connected by a clutch or the like, and the clutch is connected/disconnected under electronic control. In this type of automatic transmission, when the shift lever is operated to a predetermined position (normal position), the clutch is automatically engaged/disconnected at a shift point determined by the amount of depression of the accelerator pedal and the vehicle speed. Ru. This shift point is set to a characteristic (shift schedule) according to the performance of the engine installed in the vehicle, the specifications of the vehicle, etc., so that each vehicle can obtain an appropriate gear ratio.

(Problem to be solved by this invention) However,
In the automatic transmission of such a car, when the car drives in a place with thin air such as a high altitude where atmospheric pressure is low, the output of the engine decreases compared to when driving in a normal lowland, so the driver There was a problem in that the vehicle's driving performance seemed to have deteriorated.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an automatic transmission for an automobile that compensates for a decrease in the driving performance of the automobile due to a decrease in engine output when driving at high altitudes by correcting the shift point. It is an object.

(Means for Solving the Problem) This invention detects the vehicle speed and the valve opening of the throttle valve, and selectively switches between each element of the transmission gear mechanism at a transmission point determined by the vehicle speed and the valve opening of the throttle valve. An automatic transmission for an automobile that performs a gear shifting operation by connecting and disconnecting is provided with an atmospheric pressure detecting means for detecting atmospheric pressure, and a shift schedule adjusting means for changing the shift point based on an output signal of the atmospheric pressure detecting means. The gist is that.

(Function) According to the automatic transmission for an automobile according to the present invention, the shift point is changed to the high speed side when the atmospheric pressure decreases, so the same gear stage is maintained up to a higher speed rotation range of the engine.

As a result, the engine is operated at high output, and the driving performance of the vehicle does not deteriorate.

(Example) Hereinafter, embodiments will be described based on the accompanying drawings.

1 to 4 show an automatic transmission for an automobile according to an embodiment of the present invention, in which FIG. 1 is a skeleton diagram showing a power transmission system, FIG. 2 is a hydraulic circuit diagram, and FIG. 3 is a flow chart. , FIG. 4 is a diagram showing the shift schedule.

First, to explain the outline based on Fig. 1, (E) is an engine, and the engine (E) has a crankshaft (1), a torque converter (T), a transmission gear mechanism (M), and a differential gear (Of ), etc., to the left and right drive wheels (W).

As is well known, the torque converter (T) consists of a pump impeller (2), a turbine launch (4) and a stator (5).
and an engine (E) input to the pump impeller (2).
) is output from the turbine launch (4) to the speed change gear mechanism (M) by the action of fluid. This torque converter (T
) is provided between the pump impeller (2) and the turbine launch (4) with a direct coupling clutch (cd) that can directly connect the turbine launch (0) and the pump impeller (2).This direct coupling clutch (Cd) is supplied with hydraulic pressure from a hydraulic control circuit described later to directly connect the pump impeller (2) and the turbine launch (4).The torque converter (
Details of T) and the transmission gear mechanism (M) explained below.
For details of the hydraulic control circuit, please refer to the patent application filed by the applicant on June 13, 1985. The following explanation will be simplified as it is described in detail in the book.

The speed change gear mechanism (M) consists of a main shaft 7) (3) connected to the turbine launch (4) of the torque converter (T) and a counter shirt (1) connected to the differential gear (Dr).
B) are arranged in parallel, and these shirts) (3).

(1B) 5 gear trains (G+) corresponding to the number of gears between
.

(G2), (G3), (G4), (Gr)
are arranged side by side. The gear train (G gear) for the first forward speed is connected to the driving gear (17) connected to the main shaft (3) via the first speed clutch (C1), and the countershaft ( 16) One-way clutch (G
and a driven gear (18) connectable via o). Similarly, the second forward gear train (G2) includes a drive gear (18) connected to the main shaft (3) via a second speed clutch (C2), and a countershaft (1).
The third forward speed gear train (G3) consists of a driven gear (20) that is fixed to the main shaft (3) and meshes with the drive gear (19). 21)
and the third speed clutch (C3) is connected to the countershaft (1B).
) and a driven gear (22) that meshes with the driving gear (21).
G) is connected to the main shaft (3) by the 4th speed clutch (C).
The driving gear (23) is connected to the main shaft (3) via a switching clutch (Cs), and the driven gear (20) is connected to the counter shaft (1B) via a switching clutch (Cs) and meshes with the gear (23). .Furthermore, the reverse gear train (Gr
) is a driving gear (25) provided integrally with the driving gear (23) of the fourth speed gear train (G4), and a driven gear connected to the countershaft (1B) via the switching clutch (Cs). Gear (2B) and both gears (25), (2f()
and an idle gear (27) meshing with the idler gear (27). Each clutch (C+), (C2), (03) mentioned above.

(C4) is connected to a hydraulic control circuit, and is connected or disconnected according to the hydraulic pressure supplied from the hydraulic control circuit. Switching craft (C
s) is provided between the driven gear (20) and the idle gear (27) of the fourth speed gear train (G4), and the clutch (C
g) By shifting the selector sleeve (S) to the forward position on the left or the reverse position on the right in FIG. (113) by selectively connecting to (113). One-way clutch (Go
) transmits only the driving torque from the engine (E) to the driving wheels (W), and does not transmit torque in the opposite direction.

This speed change gear mechanism (M) can be operated by connecting only the first speed clutch (CI) when the selector sleeve (S) is held in the forward position as shown in FIG. is connected to the main shaft (3) to establish a first speed gear train (G]), and torque is transmitted from the main shaft (3) to the countershaft (lfl) via this gear train (G+). Next, if the second speed clutch (C2) is connected while the first speed clutch (-) is connected, its drive gear (18) is connected to the main shaft (3) and the second speed gear train (G2) is connected. ) is established, and this gear train (C9)
from the main shaft (3) to the counter shaft (
Torque is transmitted to 16). At this time, the first gear clutch (C1) is also engaged, but the one-way clutch (C1) is also engaged.
Due to the movement of
2) is established, and the same holds true for third and fourth speeds. When the second speed clutch (C2) is released and the third speed clutch (C3) is connected, the driven gear (22) is connected to the countershaft (IB) and the third speed gear train (G3) is connected.
is established, and if the third gear clutch (C3) is released and the fourth gear clutch (C4) is connected, the drive gear (2
3) is connected to the main shaft (3) to establish a fourth speed gear train (G4). Furthermore, by moving the selector sleeve (S) of the switching clutch (Cs) to the right as shown in Fig. 1 and connecting only the 4th speed clutch (C4), its drive gear (23)
is connected to the main shaft (3), and the driven gear (24)
is connected to the countershaft (1B) and the reverse gear train (
Cy) is established, and reverse torque is transmitted from the main shaft (3) to the counter shirt (1B) via this gear train (Gy).

The torque transmitted to the countershaft (IEI) is transferred to the output gear (28) provided at the end of the shirt (113).
is transmitted to the large diameter gear (portion g) of the differential gear (Of). One end of a speedometer cable (30) is fixed to the gear (28) that meshes with the gear (Os) fixed to the gear (Dg), and a vehicle speed detector ( A speedometer (32) is connected via the magnet (31a) of the gear (Ds), (29) and the cable (31).
30) and displays the vehicle speed. In addition, the vehicle speed detection 41 (31) is operated by the magnet! (31a) and the magnet (31a), for example, a reed switch (3lb), which rotates together with the speedometer cable (30).
The reed switch (31b) is opened and closed, and the on and off signals associated with this opening and closing are sent to the electronic control device (33), which will be described later.
supplied to

FIG. 2 represents a hydraulic control circuit.

In the figure, (P) is the aforementioned hydraulic pump that pressurizes and discharges the hydraulic oil in the reservoir (R), and the hydraulic pump (
P) discharges pressure oil to the regulator valve (Vr), manual valve (Vm), and governor valve (Vg). The regulator valve (Vr) has a spool (82a) as a port (eob).
In response to the pressure of pressure oil supplied from the pump (P) and the elastic force of the spring (82b), the boat (130a)
, a part of the pressure oil supplied from the pump (P) to (lllOb) is transferred from (lllOc) to the torque converter (T), on-off valve (230), and timing valve (230).
10), and the hydraulic pressure is regulated to line pressure (PF) by flowing back from the valve (80d) to the reservoir (R) and supplied to the manual valve (V■), etc. In addition, (25
3) is the regulator valve (Vr) bow) (llod
) is a relief valve installed in the

As is well known, in the torque converter (T), supplied pressure oil flows from the pump impeller (2) through the stator (5) to the turbine launch (4), and torque is transmitted using this pressure oil as a medium. do. The oil pressure of this torque converter (T) is controlled by a pressure holding valve (250) and an oil cooler (211).
0) to the reservoir (R). Pressure holding valve (250
) is guided by the governor pressure (described later) generated by the governor valve (Vg) (250b), and the spool (251) responds to the governor pressure and the elastic force of the spring (252),
Torque converter (T) flowing into (250a)
) by applying resistance proportional to the vehicle speed to the pressure oil from ) (
250c) to the reservoir (R). This pressure holding valve (250) is connected to the torque converter (
It functions to reduce the internal pressure of T).

The manual valve (V■) responds to the manual operation of the shift lever by the spool (71), and moves to the drive position (P) and the reverse position (R).
), neutral position (N), automatic transmission position with 4 forward gears (C4)
, 6 shift positions: automatic shift position (C3) of 3 forward speeds excluding 4th speed and fixed position (2) of 2nd speed -
Depending on each clutch (C+), (C2), (C3
), (C4) and each boat (7oa) to (70n) connected to the servo piston (80) etc. 0 For example, when the shift lever is operated to the N position, the manual valve (Vm) The spool (71) is in the illustrated position to close the boat (70b) and all other boats (70a).

(70c) to (70n) are communicated with the drain port (EX). Therefore, as is clear from the figure, each clutch (C+), (C2), (
No pressure oil is introduced into C3) and (C4),
These clutches (C1) to (C4) are placed in a disconnected state. Further, for example, when the shift lever is operated to the (04) position, the spool (71) moves to the left by one position in the figure, and the servo piston (90), the first throttle valve (V), and the pressure reducing valve (270) move to the left. Connect the boat (1?Oc) connected to the flow control valve (400) and the non-creep valve (Vc) (70h) to the boat (?Ob) connected to the pump (P), Connecting the boat (70g) connected to the second gear clutch (C2) and the boat (70f) connected to the second shift valve (v2),
Furthermore, the fourth speed clutch (C4) and timing valve (
The boat (70k) connected to the boat (70k) and the boat (70n) connected to the second shift valve (v2) are isolated from and communicated with the boat (704). Note that a description of the case where the shift lever is operated to another position will be omitted.

The servo piston (90) has each boat (SOa)
.

(90b) and (90c) are the manual valve (Vm) boats (70i).

(70c), the pressure in the chamber where pressure oil is introduced from (?Oa) and the spool (91a) communicates with the boat (IllOb), the pressure in the chamber that communicates with (90c) and the elastic force of the spring (91b) Displaced according to. This servo piston (80) has a spool (91a) whose right end in the figure is the selector sleeve (Cs) of the aforementioned switching clutch (Cs).
S) and connect the manual valve (V) to the bow) (90b).
), the selector sleeve (S) is held in the position shown in FIG.
Connect to.

The governor valve (Vg) connects the pump (P) to the boat (80a).
of the discharged oil is guided, and this discharged oil is subjected to a pressure proportional to the vehicle speed (
The pressure is regulated to the governor pressure (Pg)) and output from the governor pressure (Pg) (80b) to the second shift valve (v2), the modulator valve (220), and the above-mentioned pressure holding valve (25G).

The first throttle valve (Vt) has a first spool (10) engaged with a cam (104) that interlocks with the throttle valve.
1) The second spool (102) coupled to the first spool (1o1) via the spring (103) is connected to the cam (
104) and is displaced by the manual valve (Vm).
The pressure oil supplied to (100a) is adjusted to create a pressure (throttle pressure (Pt)) proportional to the valve opening of the throttle valve, that is, the amount of depression of the accelerator pedal.
is generated on the boats (100b) and (100c).

The Strotz pressure (pt) generated by the first throttle valve (vt) is applied to the second accumulator (170) and the fourth throttle valve (pt).
Accumulator (tSO), modulator valve (220
), on-off valve (230), flow control valve (400)
, the first control valve (lflO), the second control valve (11
11) and the third control valve (1112).

Moreover, this first throttle valve (Vt)) is connected to the second shift valve (vt) by the displacement of the first spool (101).
X) to reduce the shift shock during kickdown.

The pressure reducing valve (270) is a well-known one. (270a)
The line pressure (P!L) introduced from the manual valve (Vl)
) is depressurized and output from (270b) to the first shift valve (vl).

The flow control valve (400) is
Boat (400b), (400
c) is the manual valve (Vm), and the boat (400d
) is connected to the throttle valve (Vt), and the spool (40
1) adjusts the amount of fIt supplied to the first shift valve (vl) in response to the throttle pressure (Pt) introduced from the throttle valve (Vt) and the elastic force of the spring (402). This flow control valve (400) controls the amount of oil supplied to the first shift valve (vl) in proportion to the throttle pressure (pt) to prevent multiple clutches from being connected at the same time. to reduce shift sluggishness.

The first shift valve (Vl) includes a boat (12Qa) connected to a pressure reducing valve (270), a boat (12Qa) constantly communicating with this boat (120a), and a boat (12Qa) connected to a first solenoid valve (item 0).
2b), a boat (120c) opened to a drain (EX) and connected to a second control valve (1131);
), boat (12
0d), (120e), baud) (120f) which is opened to the drain (EX) and communicated to the second throttle valve (110), and baud) (120g) which is communicated to the flow control valve (400). and a first solenoid valve (14
The spool (121a) responds to the oil pressure of the boat (120b) controlled by the boat (120b) (2?Ob) and the elastic force of the spring (121b), and the boat (120c), ( 120d), (120
e).

(120f, (120g)).In other words, in the illustrated position where the spool (221a) is at the right end in the figure, the boats (120c), (120d) and the boats (120e), (120g) communicate selectively. communication, and in the position where the spool is displaced to the left end in the figure, the bow)
(120d) (120g) and boat (120e)
) and (120f) communicate with each other. First solenoid valve (104
), the solenoid (14,0a) is connected to the electronic control device described later, and when the solenoid (140a) is energized, it opens and the first shift valve (V+) no port (120b)
Open L/D (EX).

The second throttle valve (lie) has a spool (111) engaged with a cam (113) that communicates with the throttle valve.
is driven by the cam (113) and the spring (112)
is displaced against the elastic force of and connected to the first shift valve (vl) (110a), ! =! J server (E
X) Continuously change the flow path area between (EX) and (EX). This second throttle valve (
110) adjusts the pressure of the 117th shift valve (V+) (7) baud (120f) (7) to reduce shift shock when downshifting from 4th speed to 3rd speed.

The second shift valve (vt) is connected to the governor valve (Vg) (130a), the first throttle valve (Vt
) connected to the boat (130b), the first shift valve (
boat (13) connected to boat (120d) of vl)
0c), Bau 1 connected to the second solenoid valve (150)
(+30d), baud of the first shift valve (Vl)) (1
Boat (130e) connected to 20e), -y=al valve (Vm) Boat (130e) connected to no boat (70f)
30f), boat 1 (70m) with manual valve (Vl), boat (13) connected to (70n)
0g), manual valve (Vl) bow) (70a) connected to the boat (13(H), first control valve (180)
(130k) and a boat (130h) connected to the third gear craft (C3), and the spool (131) is connected to the boat (130a), (130k).
The hydraulic pressure and spring (
132). This second shift valve (
vt) when the spool (131) is in the illustrated position at the right end in the figure, the bow ((130b) and the boat (130
h), Boat (130c) and Boat (130F),
and the boat (130g) and the drain boat (EX), and when the spool (131) is at the left end position in the figure, the boat (130c) and the boat (130
h) Connect the boat (130f) with the boat (130k) and the boat (130g). This second shift valve is controlled and the second solenoid valve (1
50) at the illustrated position, and the second solenoid valve (1
When the valve 50) is closed, it takes the leftmost position in the figure. In addition, (1
33) is a click motion mechanism that selectively limits the position of the spool (131).

The non-creep valve (Vc) is connected to the boat (300a), (300b) connected to the manual valve (V■), and the boat (300c) connected to the manual valve (V■) via the third solenoid valve (310). ), a boat (300d) connected to the first gear clutch (C1) and a boat (300d) connected in parallel to the check valve (50m) and the third control valve (182)
(300e), and the spool (301) is the boat (300e).
00a) and (300e) and the spring (30
2) in response to the elastic force. The spring (302) is
Bolt (30
3) and the spool ('101), and by changing the threaded length of the bolt (303), the spool (301)
) is adjusted. This non-creep valve (Vc) closes the boat (300C) to communicate between the boat (300b) and the boat (300d) in the illustrated position where the spool (301) is at the lower end in the figure, and When the spool (301) is at the upper end position in the figure, the boat (300C) is further communicated with the drain boat (EX). The third solenoid valve (310) includes a solenoid (310
a) is connected to the electronic control unit, and the solenoid (310a
) opens when energized.

The third control valve (IE12) controls the boat (300e) of the non-creep valve (Vc) when the slotting pressure (pt) is small.
) to introduce the throttle pressure (pt) into the throttle pressure (pt
) is large, the line pressure (Pi) is introduced.

The timing valve (210) is connected to a second gear clutch (C2) (210a), a fourth gear clutch (C2), and a fourth gear clutch (C2).
4), a boat (210b) connected to the regulator valve (Vr), a boat (210c) connected to the inlet port of the torque converter (T), and a boat (210c) connected to the inlet port of the torque converter (T).
d) and two boats (210e) and (210f) connected to the moshulator valve (220), and the spool (211) is connected to the spring (212) (7) and the elastic force of the boats (210a) and (210b). Respond to pressure. This timing valve (210) is connected to the second speed clutch (
When the 2nd speed clutch (C2) or the 4th speed clutch (C) is in the engaged state, the spool (211) moves to the left in the figure and assumes the leftmost position in the figure, and the 2nd speed clutch (C2) or the 4th speed clutch (C) is engaged.
When C4) is in the released state, the spool (211) moves to the right in the figure and assumes the position shown at the right end in the figure. This timing valve (
210) communicates between the boats (210c) and (210e) when repositioned at the left end in the figure and the right end in the figure, but in the middle of the transition, the boats (210c) and (216e) are disconnected, and the boat (210f ) from the drain boat (EX).

The modulator valve (220) is a first throttle valve (V
t) to which the throttle pressure (Pt) is introduced from the boat (2
20a), governor pressure (Pg) is introduced from the governor valve (Vg) (220b), timing valve (210
) (220c), (220
d) the boat (2) connected to the on-off valve (230);
20e) and a bow) (220f) connected to the direct coupling latch (Cd), and the spool (221) responds to the internal pressure of the direct coupling clutch (Cd), throttle pressure (Pt) and governor pressure (Pg). A pressure proportional to the vehicle speed and the opening degree of the throttle valve is output to the on-off valve (230).

The on-off valve (230) is a first throttle valve (Vt)
throttle pressure (pt) is introduced)
(230a), a boat (230b) connected to the regulator valve (Vr), a boat (230C) connected to the inlet boat of the torque converter (T), a boat (230C) connected to the outlet boat of the torque converter (↑) 230
d) and a bow (230e) connected to the modulator valve (220), the spool (231) responding to the throttle pressure (pt) and the elastic force of the spring (232). This on-off valve (2]0) is used when the engine is idling with a small throttle pressure (pt).
(230a) is connected to the drain boat (EX), and the boats (230b) and (230c) are connected to release the direct coupling clutch (Cd) and increase the amount of oil supplied to the torque converter (T). let

In the direct connection clutch (Cd), the outlet boat is also connected to the fourth solenoid valve (240), and this $4 solenoid valve (240) is connected to the fourth solenoid valve (240).
0). When the solenoid (240a) is connected to the electronic control device and the solenoid (240a) is energized and excited, the fourth solenoid valve (240) operates as a direct clutch (
The boat (241) that contacted the drain boat (E
X) to shift the direct coupling clutch (Cd) to the released state.

The second speed clutch (C2) is the 27th curator (170)
The third gear clutch (C3) is connected in parallel with the 37th gear clutch (C3).
Cumulator (180) and first control valve (ieo)
The fourth speed clutch (C4) is connected in parallel with the fourth accumulator (1110) and the second control valve (
As is well known, each space, AL/-ta (170), (180), (1110
) reduces gear shift shock, and the first control valve (16
0) and the second control valve (161) determine the characteristics when the clutch is released. In addition, in FIG. 2, (CI) represents an aperture.

(800) is an electronic quantity control device equipped with a one-chip microcomputer, etc., and this electronic control device (800) includes a vehicle speed sensor that detects vehicle speed and an atmospheric pressure sensor (atmospheric pressure detection means) that detects atmospheric pressure (801). , the above-mentioned electromagnetic valves (140) together with various sensors such as a vehicle speed sensor (802) that detects the vehicle speed or an accelerator sensor (803) that detects the valve opening of the throttle valve.

(150), (240), (310), etc. are connected, and the electronic control device (800) controls the energization of the solenoid valve based on the output signal of each sensor.This electronic control device (800) constitutes a shift schedule adjustment means. do.

As shown in the table below, in such a hydraulic control circuit, the solenoids (140a) and (150c) of the first and second solenoid valves (140) and (15G) are connected to the electronic control device (800).
) is selectively energized to open the valve, and each clutch (G
1) , (C2), (C3), and (C4) are controlled to establish any one of the first to fourth speeds of the transmission gear mechanism (M) according to the vehicle speed and the opening degree of the throttle valve. .

A detailed explanation of this hydraulic control circuit will be omitted.

Next, the operation of this embodiment will be explained.

The automatic transmission of this automobile is controlled by an electronic control unit (eoo) that repeatedly executes a series of processes shown in the flowchart of FIG. 3 at predetermined intervals.

First, when the ignition switch is turned on, initialization processing of the CPU of the electronic control unit (800) is performed in step (Pl). In the next step (P2), it is determined whether the engine (E) is in an operating state or not, that is, the rotational speed (Ne) of the engine (E) is a predetermined rotational speed (Neo) (for example, 300 [r, p, m, 1)], and determines whether the rotation speed (Ne) of the engine (E) exceeds the predetermined rotation speed (
If the engine (E) is in an operating state beyond Neo), the process advances to step (P3), and if the engine (E) rotational speed (Ne) is below the predetermined rotational speed (Men), the process proceeds to step (P4). move on.

In step (P3), the vehicle speed sensor and the atmospheric pressure sensor (
Input data is read from various sensors such as 801), and input data processing such as storage of the input data is performed in the following step (P5). Then, in the next step (P6),
Calculate the speed ratio (e) of the torque converter (T). This speed ratio (e) is obtained as the ratio of the rotation speed of the turbine launch (0) and the rotation speed of the pump impeller (2). In the following step (P7), non-creep control is performed based on vehicle speed data etc. In step (P7), the third
The current to be applied to the solenoid (310a) of the solenoid valve (310) is determined, and the energization of the third solenoid valve (1B2) is controlled by the output processing in step CP+a) to be described later, and the first speed clutch (lE+) is Adjust the hydraulic pressure supplied to.

In the next step (P8), atmospheric pressure (PA) is changed to a predetermined pressure (
PAO) (for example, 670 [mmHG]), and determines whether atmospheric pressure (PA) is smaller than a predetermined pressure (PAO
), the process proceeds to step (P9), and if the atmospheric pressure (PA) is equal to or higher than the predetermined pressure (PAD), the process proceeds to step (P+o). In step (P9), the shift schedule for low pressure is read from the second data table,
In step (Pro), the normal shift schedule for flat areas (for high pressure) is read from the first data table.
These low-pressure shift schedules and flatland shift schedules are shown in Figure 4 for forward 1st and 2nd speeds. is set on the higher speed side. In other words, downshift (2→
l) Also, regardless of the upshift (l→2), the shift point for flat terrain (solid line) is set to the lower vehicle speed side than the shift point for high altitude (broken line). After that, in step (P1), the automatic transmission is controlled based on the read shift schedule. That is, if the low pressure shift schedule is selected in step (P9), the solenoid valve (
By performing the on/off control of 140) and (150) in a higher vehicle speed range, processing is performed such that the automatic transmission maintains the same gear stage up to a higher vehicle speed position, and the engine (E) is kept in a high output state. Let them drive. Therefore, even if the vehicle travels in a place with low atmospheric pressure, such as at a high altitude, the vehicle's driving performance will not deteriorate.

In the next step (PI3), the capacity of the direct coupling clutch (Cd) of the torque converter (T) is controlled based on the speed ratio (e) etc. calculated in the above step (Pa).

On the other hand, in the aforementioned step (p4), processing is performed to maintain the gear position of the automatic transmission at the third forward speed, and the following step (h
Step a) performs the process of releasing the direct coupling clutch (Cd).

After this, in step (ha), output processing such as energizing the solenoid valve is performed based on the processing results of each step described above, and after the processing of this step (Plm) is completed,
The series of processes starting from step (P2) is repeated again.

In the embodiment described above, the shift schedule for low pressure is read from the data table when the atmospheric pressure is low, but it is also possible to calculate the shift schedule for low pressure from the normal shift schedule for flat terrain.

(Effects of the Invention) As explained above, according to the automatic transmission for a vehicle according to the present invention, when atmospheric pressure is low, shift control is performed based on a shift schedule in which the shift point is set in a high vehicle speed range. Since the engine is operated at high output, it prevents the vehicle's driving performance from deteriorating under low pressure.
can.

[Brief explanation of drawings]

1 to 4 show an automatic transmission for an automobile according to an embodiment of the present invention, in which FIG. 1 is a frame diagram of a power transmission system, FIG. 2 is a hydraulic circuit diagram, FIG. 3 is a flowchart, and FIG. Figure 4 is a data table showing the shift schedule. E... Engine Cd... Direct clutch T... Torque converter M... Speed change gear mechanism (C+), (Cri), (C3), (C4),
(Cs)...Clutch (140), (150), (
240), (310)...Solenoid valve (eoo)...Electronic control device (shift schedule adjustment means) (801)...Atmospheric pressure sensor (atmospheric pressure detection means) (80
2)...Vehicle speed sensor

Claims (2)

[Claims] (1) An automobile that detects the vehicle speed and the opening of the throttle valve and selectively connects and disconnects each element of the transmission gear mechanism at the shifting point determined by the vehicle speed and the opening of the throttle valve. An automatic transmission for an automobile, characterized in that the automatic transmission comprises an atmospheric pressure detection means for detecting atmospheric pressure, and a shift schedule adjustment means for changing the shift point based on an output signal of the atmospheric pressure detection means. Machine. (2) The seat schedule adjustment means stores a first data table storing a normal shift schedule, and a shift schedule for low pressure in which a shift point is set to a higher vehicle speed side than the shift schedule of the first data table. and a second data table in which the atmospheric pressure is stored, and when the atmospheric pressure is less than a predetermined value, a shift schedule for low pressure is read from the second data table and a shift point is set based on the shift schedule for the low pressure. An automatic transmission for a motor vehicle according to claim 1, characterized in that the automatic transmission for an automobile changes: