JP2991532B2 - Control device for engine and automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an engine and an automatic transmission.

[0002]

2. Description of the Related Art Generally, an automatic transmission for an automobile is provided with a torque converter and a transmission gear mechanism. here,
The torque converter shifts the torque of the engine output shaft and transmits the torque to the turbine shaft, and the transmission gear mechanism further shifts the torque of the turbine shaft and reverses the rotation direction during reverse to transmit the torque to the drive wheels. It has become. The above-mentioned transmission gear mechanism usually comprises a planetary gear system including a sun gear, a ring gear, a pinion gear, and a carrier, and the transmission gear mechanism connects or disconnects (turns on and off) a turbine shaft and predetermined gears. A plurality of clutches and a plurality of brakes for fixing or releasing (on / off) a predetermined gear or carrier are provided. In the transmission gear mechanism, the on / off pattern of each clutch and each brake is switched by a hydraulic mechanism, whereby the power transmission path in the planetary gear system is switched, and the speed change and forward /
Reverse switching is performed.

In such an automatic transmission, when shifting,
For example, when downshifting from fourth speed to third speed, the coast clutch is turned on while the 2-4 brake is turned off. In such a shifting operation, when the coast clutch starts to be engaged in the middle stage of the shifting, the amount of transmission of the engine torque to the driving wheel side sharply increases, so that a phenomenon in which the longitudinal acceleration of the vehicle body sharply increases, so-called thrust up, There is a problem that a shift shock occurs. For this reason, generally, in vehicles equipped with an automatic transmission, the engine torque is reduced at the time of gear shifting in order to prevent the occurrence of shift shock due to such thrust. Since the shift shock generally depends on the torque input from the engine side to the transmission side (transmission side input torque), a torque down characteristic such as a torque down timing is changed according to the transmission side input torque. Is preferred. Therefore, there has been proposed a torque-down control unit that changes the timing of the torque-down based on the engine speed related to the output torque of the engine (see Japanese Patent Publication No. 2-20817).

[0004]

However, although the engine speed is related to the output torque of the engine, it cannot accurately grasp the output torque of the engine. It is not something you can grasp. For this reason, in the above-described conventional torque-down control means in which the timing of the torque-down is changed based on the engine speed, the torque-down is always performed at an appropriate timing according to the state of occurrence of the transmission input-side torque during gear shifting. Therefore, there is a problem that the occurrence of a shift shock cannot be effectively prevented.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and is intended to reduce the input torque of the transmission in a vehicle equipped with an automatic transmission in which the engine torque is reduced at the time of shifting. It is an object of the present invention to provide an engine and a control device for an automatic transmission, which can perform torque reduction at an appropriate timing in response thereto and effectively prevent occurrence of a shift shock.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the control apparatus for an engine and an automatic transmission according to the first aspect of the present invention includes: (a) reducing the torque of the engine when shifting the automatic transmission; In a control device for an engine and an automatic transmission provided with a torque changing means for performing
Timing change means for changing the timing of the torque reduction by the torque change means based on a state in which the transmission input torque follows the engine load change,
(C) The timing changing means grasps the follow-up state of the transmission input torque with respect to the engine load change based on the input / output characteristics of the torque converter at the beginning of the shift, and the speed ratio (torque converter speed ratio) representing the input / output characteristics is determined. When the speed ratio is smaller than the predetermined value, the torque reduction is started earlier than when the speed ratio is larger than the predetermined value.

The control apparatus for an engine and an automatic transmission according to the second invention of the present application includes: (a) control of an engine and an automatic transmission provided with torque changing means for decreasing the torque of the engine when shifting the automatic transmission; In the device,
(B) timing changing means for changing the timing of torque reduction by the torque changing means based on a state of the transmission input torque following the change in engine load; and (c) the transmission changing means for changing the engine load in response to the change in engine load. The follow-up state of the input torque is grasped based on the input / output characteristics of the torque converter in the initial stage of the shift, and when the speed ratio (torque converter speed ratio) representing the input / output characteristics is smaller than a predetermined value, the turbine rotation increases after the shift command. It is characterized in that torque reduction is started before turning.

The control device for the engine and the automatic transmission according to the third invention of the present application is the control device for the engine and the automatic transmission according to the second invention of the present application, wherein the timing changing means includes: This is characterized in that the start of the torque down is delayed only by.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below.
As shown in FIG. 1, an FF provided with a horizontally mounted power plant PT including a four-cylinder engine 1 and an automatic transmission T
In a vehicle (front engine / front drive vehicle), after the output torque of the engine 1 is shifted by the torque converter 2 and the multi-stage transmission gear mechanism 3 constituting the automatic transmission T, the output torque of the right and left The power is transmitted to the front axle shafts 5 and 6. In each cylinder of the engine 1, a mixture is supplied into the cylinder 8 from the independent intake passage 7, and the mixture is compressed by a piston (not shown) and then ignited and burned by a spark plug 9. And
Thereafter, the combustion gas is discharged through the independent exhaust passage 10. Here, each of the fuel injection valves 11 injects fuel into intake air, facing each independent intake passage 7.
Is provided. The ignition plug 9 is supplied with high-voltage ignition power at a predetermined timing by the distributor 13, the ignition coil unit 14, and the ignition control unit 15. Each independent intake passage 7 is gathered on the upstream side into one common intake passage 17, and a throttle valve 18 that opens and closes in conjunction with an accelerator pedal (not shown) is provided in the common intake passage 17. .

As shown in FIG. 2, in the automatic transmission T, the torque converter 2 changes the torque of the engine output shaft 21 and transmits it to the turbine shaft 22, and the transmission gear mechanism 3 controls the torque of the turbine shaft 22. Is further shifted, and when the reverse gear is selected, the rotation is reversed, and the differential device 4
(See FIG. 1). The turbine shaft 22 is formed in a pipe shape, and a pump shaft 26 connected to the engine output shaft 21 is provided in a hollow portion of the turbine shaft 22. The pump shaft 26 drives an oil pump 27 to rotate. I have.

The torque converter 2 is substantially composed of a pump 29 connected to the engine output shaft 21 through a connecting member 28 and a turbine connected to the turbine shaft 22 and rotationally driven by hydraulic oil discharged from the pump 29. 3
0 and a stator 3 for rectifying the hydraulic oil returning from the turbine 30 to the pump 29 in a direction to promote the rotation of the pump 29.
The torque of the engine output shaft 21 is shifted at a speed ratio according to a difference in the number of revolutions between the pump 29 and the turbine 30. Here, the stator 31 is connected to the transmission case 33 via the stator one-way clutch 32.
It is fixed to. A lock-up clutch 34 for directly connecting the engine output shaft 21 and the turbine shaft 22 is provided as needed.

The transmission gear mechanism 3 is a commonly known ordinary planetary gear system.
The small sun gear 35 having a relatively small diameter loosely fitted to the turbine shaft 22 and the large sun gear 36 having a relatively large diameter loosely fitted to the turbine shaft 22 behind the small sun gear 35 (right side in FIG. 2). , A plurality of short pinion gears 37 meshing with the small sun gear 35
(Only one is shown), a long pinion gear 38 whose front portion (left side in FIG. 2) meshes with the short pinion gear 37, and a rear portion meshes with the large sun gear 36, a ring gear 39 which meshes with this long pinion gear 38, a short pinion gear 37 and a long pinion gear. A carrier 40 rotatably supporting the pinion gear 38 is provided. In this transmission gear mechanism 3, the small sun gear 3
5, while the large sun gear 36 or the carrier 40 serves as a torque input section, the ring gear 39 serves as a torque output section at any speed. The ring gear 39 is connected to the output gear 24.
It is connected to.

A plurality of clutches and brakes are provided for switching the torque transmission path in the transmission gear mechanism 3, that is, for switching the gear ratio or switching the rotation direction of the output gear 24. Specifically, a forward clutch 41 and a first one-way clutch 42 are interposed between the turbine shaft 22 and the small sun gear 35 in series, and both clutches 4
A coast clutch 43 is interposed in parallel with 1, 42. Then, the turbine shaft 22 and the carrier 4
0, a 3-4 clutch 44 is interposed, and between the turbine shaft 22 and the large sun gear 36, a reverse clutch 45 is interposed. Further, between the large sun gear 36 and the reverse clutch 45, a band brake which is actuated by a servo piston for fixing the large sun gear 36 at a predetermined shift speed is formed.
Four brakes 46 are provided. In addition, carrier 4
A low reverse brake 47 for fixing the carrier 40 at a predetermined shift speed and a second one-way clutch 48 for receiving the reaction force of the carrier 40 are provided in parallel between the transmission case 33 and the transmission case 33 '. . In the following, these clutches and brakes will be referred to as "friction fastening elements" as appropriate.
Collectively.

The clutches 41, 43, 44, 45
By changing the ON / OFF patterns of the brakes 46 and 47 and the various ranges or shift speeds shown in Table 1, various ranges or shift speeds can be obtained. Hereinafter, with reference to Table 1, a description will be given of a torque transmission path and a shift characteristic thereof in each range or shift speed.

[0015]

[Table 1]

(1) P range (parking range): All the friction engagement elements are turned off. In this case, the torque of the turbine shaft 22 is not transmitted to the transmission gear mechanism 3. (2) R range (reverse range) ... reverse clutch 45
And the low reverse brake 47 are turned on, and the other frictional engagement elements are turned off. Since the low reverse brake 47 is turned on, the second one-way clutch 48 disposed in parallel with the low reverse brake 47 has no particular effect. The first one-way clutch 42 deviates from the torque transmission path, and does not exert any special action. In this case, the turbine shaft 22
Is input to the large sun gear 36 via the reverse clutch 45. Since the carrier 40 is fixed by the low reverse brake 47, the large sun gear 36, the long pinion gear 38, and the ring gear 39 function as a fixed gear train that meshes in this order. Accordingly, the torque input to the large sun gear 36 is transmitted through the gear train in the above order, and is shifted at a large reduction ratio determined by the number of teeth of the large sun gear 36 and the number of teeth of the ring gear 39. Is output. In this R range, the ring gear 39 (output gear 2)
4) rotates in the opposite direction to the large sun gear 36 (turbine shaft 22), and the front axle shafts 5, 6 (FIG.
) Is driven to the reverse side. (3) N range (neutral range) ... similar to the case of the P range.

(4) D range (drive range) first speed: The forward clutch 41 is turned on, and the other frictional engagement elements are turned off. The first and second one-way clutches 42 and 48 are normally in a locked state, but idle during coasting. In this case, the torque of the turbine shaft 22 is sequentially increased by the forward clutch 41 and the first one-way clutch 42.
And is input to the small sun gear 35 through. Then, the carrier 40 is controlled by the second one-way clutch 48.
Is fixed, the small sun gear 35, the short pinion gear 37, the long pinion gear 38, and the ring gear 39 function as a fixed gear train that meshes in this order. Accordingly, the torque input to the small sun gear 35 is transmitted through this gear train in the above order, and is shifted at a large reduction ratio determined by the number of teeth of the small sun gear 35 and the number of teeth of the ring gear 39, and transmitted to the output gear 24. Is output. In this case, the ring gear 39 (output gear 24) rotates in the same direction as the small sun gear 35 (turbine shaft 22), and the front axle shafts 5, 6 (see FIG. 1) are driven forward. In the first range of the D range, engine braking cannot be obtained due to the action of the first one-way clutch 42.

(5) D range 2nd speed: forward clutch 4
The 1 and 2-4 brakes 46 are turned on, and the other frictional engagement elements are turned off. The first one-way clutch 42 is normally locked, but idles during coasting. Note that the second one-way clutch 48 always idles. In this case, since the large sun gear 36 is fixed, the long pinion gear 38 revolves around the large sun gear 36 while rotating. Therefore, basically, the D range 1
Torque is transmitted along the same route as in the case of the high speed, but since the rotation speed of the ring gear 39 is increased by the revolution of the long pinion gear 38, the reduction ratio is slightly smaller than in the first range of the D range. In the second range of the D range, engine braking cannot be obtained due to the action of the first one-way clutch 42.

(6) D range 3rd speed: forward clutch 4
1, the coast clutch 43 and the 3-4 clutch 44 are turned on, and the other frictional engagement elements are turned off. Since the coast clutch 43 is turned on, the forward clutch 41 and the first one-way clutch 42 arranged in parallel therewith have no particular effect. Note that the second one-way clutch 48 always idles. In this case, the small sun gear 35 and the carrier 40 are
Are locked together via the turbine shaft 22 and the 3-4 clutch 44, so that all the gears 35 to 39 and the carrier 40 are fixed and rotate together according to the general properties of the planetary gear system. , The turbine shaft 22 and the output gear 24 are directly connected, so that the torque of the turbine shaft 22 is not changed.
(Reduction ratio 1) is transmitted to the output gear 24. In this case, the output gear 24 rotates in the same direction as the turbine shaft 22,
The front axle shafts 5, 6 (see FIG. 1) are driven forward. It is natural that engine braking can be obtained in the third range of the D range in the directly connected state.

(7) D range 4th speed: forward clutch 4
The 1 and 3-4 clutches 44 and the 2-4 brake 46 are turned on, and the other frictional engagement elements are turned off. The first and second one-way clutches 42 and 48 always idle. The first
Since the one-way clutch 42 always idles, the forward clutch 41 is ON but has no particular effect. In this case, the torque of the turbine shaft 22 is input to the carrier 40 via the 3-4 clutch 44, and the torque of the carrier 40 is sequentially transmitted to the output gear 24 via the long pinion gear 38 and the ring gear 39. . Since the large sun gear 36 is fixed by the 2-4 brake 46, the long pinion gear 38
Revolves around the large sun gear 36 while rotating.
Therefore, the rotation speed of the ring gear 39 is
From the rotation speed of the turbine shaft 22, that is,
The speed is increased by the rotation of the long pinion gear 38, and the transmission gear mechanism 3 enters an overdrive (increased) state. In addition,
The ring gear 39 is a carrier 40 (turbine shaft 22)
, And the drive wheels are driven forward.

(8) 2nd range 1st speed: The same as in the case of the D range 1st speed. (9) 2nd range 2nd speed: The forward clutch 41, the coast clutch 43, and the 2-4 brake 46 are turned on, and the other friction engagement elements are turned off. Since the coast clutch 43 is turned on, the forward clutch 41 and the first one-way clutch 42 arranged in parallel therewith have no particular effect. In this case, the torque transmission path and the shift characteristics are basically the same as those in the case of the second speed in the D range, but since the first one-way clutch 42 does not operate, engine braking can be obtained. (10) 2nd range 3rd speed: The same as in the case of the D range 3rd speed. (11) 1st range 1st speed: The forward clutch 41, the coast clutch 43, and the low reverse brake 47 are turned on, and the other frictional engagement elements are turned off. Since the coast clutch 43 is on, the forward clutch 41 and the first one-way clutch 42 arranged in parallel with the coast clutch 43
Has no special effect, and the second one-way clutch 48 disposed in parallel with the low reverse brake 47 has no special effect since the low reverse brake 47 is on. In this case, the torque transmission path and the shift characteristics are basically the same as those in the case of the first speed in the D range, but since the first and second one-way clutches 42 and 48 do not work, engine braking can be obtained. . (12) 1st range 2nd speed: Same as 2nd range 2nd speed.

As shown in FIG. 3, the hydraulic circuit unit 50 is used to switch the on / off pattern (see Table 1) of each frictional engagement element of the multi-speed transmission gear mechanism 3, that is, to switch the select range or the shift speed. Is provided. The hydraulic circuit unit 50 is a commonly used hydraulic mechanism for controlling a normal transmission. Although not shown in detail, hydraulic oil is supplied from an oil pump 27 (see FIG. 2). Is adjusted by the pressure regulator valve 52 in accordance with the operation state of the vehicle to form a line pressure, and this line pressure is adjusted according to the select range position of the manual valve and the shift position of each shift valve.
A predetermined frictional engagement element of the transmission gear mechanism 3 is supplied or released to switch a select range or a shift speed. In this hydraulic circuit section 50,
The pressure regulator valve 52 generates a line pressure corresponding to the pilot pressure generated by the line pressure control duty solenoid valve 51. Also, each shift valve (not shown) includes first to fourth
The shift is performed by solenoid valves 53 to 56 (see FIG. 1). The line pressure control duty solenoid valve 51 and the first to fourth solenoid valves 53 to 56 are controlled by a transmission control unit 58 as described later.

As shown in FIG. 1 again, an engine control unit 57 for performing predetermined various controls on the engine 1 is provided, and a transmission control unit 58 for performing predetermined shift control on the automatic transmission T is provided. Is provided. Note that the engine control unit 57 and the transmission control unit 58 are comprehensive control devices including a microcomputer including the torque changing unit and the timing changing unit described in claims 1 to 3. The engine control unit 57 outputs an engine speed signal Sn output from an engine speed sensor 61 provided for the distributor 13, a crank angle signal Sc output from a crank angle sensor 62, and an output from a water temperature sensor 63. The cooling water temperature signal Sw, the knocking intensity signal Sk output from the knocking sensor 64, the throttle valve 18
, A throttle opening signal St output from a throttle opening sensor 65 provided to the common intake passage 17, a boost signal Sb output from a boost sensor 66 provided to the common intake passage 17, and other intake air amount signals. The information is entered as information. The engine control unit 57 is also provided with a predetermined signal indicating a shift state and the like from the transmission control unit 58.
The engine control unit 57 performs normal engine control such as fuel injection control and ignition timing control based on the control information, and also prevents occurrence of a shift shock or the like during shifting of the automatic transmission T. Then, a torque down control as described later is performed.

Here, the fuel injection control is set in accordance with the operating state of the engine 1 based on the amount of air charged into the cylinder 8 calculated based on the engine speed, the intake air amount, the intake air temperature and the like. This is performed by adjusting the fuel injection pulse width of the fuel injection valve 11 so as to obtain a mixture having a predetermined air-fuel ratio (A / F). In the ignition timing control, an ignition advance value is calculated according to the operation state of the engine 1, and the ignition control unit 15 controls the ignition timing at a timing set based on the ignition advance value and the crank angle signal. A signal is output, and the ignition coil unit 14 supplies a high-voltage ignition power to each ignition plug 9 via the distributor 13 at a predetermined timing in accordance with the signal. And generally, the ignition timing is retarded
Since the output torque of the engine 1 decreases as the angle is retarded, the ignition timing is forcibly retarded by a predetermined amount when the torque of the engine 1 is reduced at the time of shifting by using this. The torque down control is performed by a method as shown in the flowcharts of FIGS.

The transmission control unit 58 includes a cooling water temperature signal Sw output from a water temperature sensor 63, a throttle opening signal St output from a throttle opening sensor 65, and a turbine speed output from a turbine speed sensor 67. The signal Su, the vehicle speed signal Sv output from the vehicle speed sensor 68,
A select position signal Ss of the select lever output from the position sensor 69 and the like are input as control information. Then, the transmission control unit 58
A predetermined shift control is performed based on these control information. This shift control is basically performed by selecting the position signal, that is, the selected range (P,
R, N, D, 2, 1 range), and the line pressure control duty solenoid valve 5 according to the throttle opening and the vehicle speed.
1 and the drive signals Ca, Cb, Cc, Cd, and Ce are applied to the first to fourth solenoid valves 53 to 56, respectively, to switch the on / off pattern of each friction engagement element of the transmission gear mechanism 3, The speed change gear mechanism 3 is switched to a select range or a speed step according to the driving state of the vehicle. For example, when the forward range, that is, the D, 2, 1 range is selected, the shift speed is automatically switched according to the throttle opening and the vehicle speed according to the shift map as shown in FIG. . Note that the line pressure control duty solenoid valve 51 is, as described above, for controlling the pilot pressure for the pressure regulator valve 52 (see FIG. 3). It is a hydraulic control means for controlling the line pressure, and includes first to third solenoid valves 53 to
Reference numeral 55 denotes a hydraulic control unit for switching a gear position, and a fourth solenoid valve 56 is a hydraulic control unit for switching on / off of the lock-up clutch 34 (see FIG. 2).

By the way, the engine control unit 57
In addition to performing normal various engine controls as described above,
At the time of shifting of the automatic transmission T, various signals applied from the transmission control unit 58 are received, and torque down control is performed so as to prevent occurrence of a shift shock due to pushing up. Hereinafter, the control method of the torque down control will be described with reference to the flowcharts shown in FIGS. 5 and 6 and appropriately referring to FIGS. It is to be noted that since such torque down control is performed at the time of all types of shifts, a control routine for torque down control is provided individually for each shift up or down shift, although not shown. I have. The meanings of the symbols used in the flowcharts shown in FIGS. 5 and 6 are summarized below. (1) NE: engine speed detected by engine speed sensor 61 (2) TVO: throttle opening detected by throttle opening sensor 65 (3) TREV: turbine rotation The turbine speed detected by the number sensor 67 (4) VSP... The vehicle speed detected by the vehicle speed sensor 68 (5) VTREV... (6) CXE: A torque-down prohibition timer for delaying the start of torque-down for a predetermined time during downshifting. (7) CRE: A torque-down end timer (8) for determining the end timing of torque-down. ) XETR... When 1 is set, the torque is reduced by retarding the ignition timing. (9) XY ........... When 1 is set, a switching flag that skips steps # 25, # 26, and # 13. (8) SFTDWN ... A downshift flag that is set to 1 when the gearshift from the third gear to the third gear is to be performed. (9) XTREV1... Torque-down start turbine speed (10) TREVn.

When the control is started, first, in step # 1
Then, the torque down end timer CRE, the torque down prohibition timer CXE, the torque down flag XETR, and the switching flag XY are initialized (all 0s are set). In step # 2, the vehicle speed VSP, the turbine speed TREV, the throttle opening TVO, the engine speed NE, and the turbine speed change rate VTREV are read. In step # 3, the shift down flag SFT
It is determined whether DWN is set to 1 or whether the torque-down end timer CRE is positive or not. The shift down flag SFTDWN is set by the transmission control unit 58.
When the driving state of the vehicle becomes a state where the downshift from the 4th speed to the 3rd speed should be performed according to the shift map as shown in FIG. 4, 1 is set, and the downshift to the 3rd speed is completed. This flag is sometimes returned to 0. The shift-down flag SFTDWN is always input from the transmission control unit 58 to the engine control unit 57. Here, if SFTDWN ≠ 1 (SFTDWN = 0) and CRE ≦ 0 (NO), there is no need to perform torque down, so in step # 21, a torque down end timer CRE and a torque down prohibition timer CXE, The torque down flag XETR and the switching flag XY are set to 0, ignition control for normal operation is performed in step # 20, and thereafter, the process returns to step # 2.

On the other hand, in step # 3, SFTDWN = 1
Alternatively, if it is determined that CRE> 0 (YES), the throttle opening TVO is less than the predetermined value TVO1 in step # 4, or the transmission control unit 58 determines that the shift-down (other than the fourth gear to the third gear) is performed. It is compared and determined whether a shift signal has been output or none of the above. In the present embodiment, in a low load state where TVO is less than the predetermined value TVO1 (hereinafter referred to as a low load state), the torque is not reduced at the time of shifting. However, at such a low load, the output torque of the engine 1 is originally small, so that the thrust-up or the shift shock can be suppressed only by adjusting the hydraulic pressure applied to each frictional engagement element of the transmission gear mechanism 3. On the other hand, if the torque is reduced, the engine torque becomes too low, and it may not be possible to secure even a torque for causing a proper slip when the frictional engagement element is turned on and off. Further, a transmission signal other than the downshift from the fourth gear to the third gear is transmitted to the transmission control unit 58.
Is output to the engine control unit 57 from
Instead of the control routine shown in this flowchart, another shift control routine (not shown) is executed, so there is no need to reduce the torque in this control routine. In step # 4, if TVO <TVO1 or another shift signal is output (YES), it is not necessary to perform torque reduction in at least this control routine. As in the case, after Steps # 21 and # 20 are executed, the process returns to Step # 2.

If it is determined in step # 4 that TVO ≧ 0 and that no other shift signal is output, (N
O), Step # 5 to Step # 9 and Step # 22
In the control routine of steps # 23 to # 23, the torque reduction start turbine speed XTREV1 is calculated, and
REV / NE is a predetermined value T ₁ is is set to the torque reduction inhibit timer CXE only if it is smaller than the predetermined value E1.

In this embodiment, the ratio TR between the turbine speed TREV and the engine speed NE in the initial stage of downshifting is shown.
When EV / NE, that is, the speed ratio of the torque converter 2 (hereinafter, referred to as the torque converter speed ratio) is less than a predetermined value E1, as described later, the torque ratio of the torque converter 2 is large, and thus the transmission gear Since the torque input to the mechanism 3 increases, the torque down is started from the beginning of the downshift so as to effectively prevent thrust up or shift shock. However, immediately after the start of downshifting, the transmission gear mechanism 3 temporarily (for a moment) becomes idle, causing a sudden drop in the longitudinal acceleration of the vehicle body. Then, such retraction is further promoted. Therefore, after the start of downshifting, so that delay the start of the torque-down by a predetermined time T _1.

During downshifting, such an operation state (TREV / NE <E1) is caused by, for example, the accelerator pedal being depressed slowly, and the change in the throttle opening, that is, the change in the engine load, the output torque of the engine or the engine rotation. This occurs when the number, and thus the input torque to the transmission gear mechanism 3, rises following. As shown in FIG. 4, since the shift map is generally created based on the throttle opening and the vehicle speed, the downshift is also performed based on the throttle opening and the vehicle speed. However, even when the throttle opening is equal, if the accelerator pedal is depressed slowly, the output torque or the engine speed of the engine is increased following the change in the throttle opening. Therefore, the torque input to the transmission gear mechanism 3 via the torque converter 2 increases. On the other hand, when the accelerator pedal is rapidly depressed, the output torque or the engine speed of the engine does not follow the change in the throttle opening and is relatively low. Therefore, the transmission gear mechanism 3
The torque input to the motor decreases. Therefore, the following state of the input torque to the transmission gear mechanism 3 with respect to the change in the throttle opening degree, that is, the change in the engine load, is grasped from the torque converter speed ratio, whereby the input torque to the transmission gear mechanism 3 is grasped. The timing at which the torque is reduced is changed to improve the shift characteristics. FIG. 7 shows a turbine speed (curve G ₁ ), an engine speed (curve G ₂ ) and a torque down signal (line G) at the time of downshifting when the torque converter speed ratio is small.
₃ ) shows the characteristics with respect to time. Hereinafter, these seven figures will be referred to as appropriate.

When the torque converter speed ratio TREV / NE in the initial stage of the downshift is equal to or more than the predetermined value E1, the torque ratio of the torque converter 2 is relatively small, so that the torque input to the transmission gear mechanism 3 is relatively small. No, the push is not so strong. For this reason, in the middle period of the downshift, the torque down is started from the time when the turbine speed TREV rises to a torque down start turbine speed XTREV1 described later. As described above, such an operation state occurs, for example, when the accelerator pedal is rapidly depressed, and the input torque to the transmission gear mechanism 3 does not follow the change in the throttle opening very much. FIG. 8 shows the relationship between the turbine speed (curve G ₁ ′), the engine speed (curve G ₂ ′) and the torque down signal (polyline G ₃ ′) during downshifting when the torque converter speed ratio is large. Shows characteristics over time.
Hereinafter, FIG. 8 will be referred to as appropriate.

The above-mentioned torque reduction start turbine speed XT
Basically, when the torque converter speed ratio is large, REV1 indicates the turbine speed TREV at the time of downshifting.
Is the turbine speed at which torque reduction is to be started when the turbine speed has increased to XTREV1,
In step # 9, calculation is performed using the following equations 1 and 2. When the torque converter speed ratio is small, the XTR
EV1 does not determine the timing of starting the torque down, but merely serves as a reference for starting the torque down end timer CRE. XTREV1 = TREV ₀ + OTR · (TREVn−TREV ₀ ) Equation 1 TREVn = TREV ₀ GR3 / GR4 Equation 2 TREV ₀ Turbine speed at start of change OTR ... A constant less than 1 that is set according to the type of shift TREVn... Expected turbine speed after downshift GR3... Gear ratio after shift (3rd speed) GR4... Gear before shift (4th speed) The ratio TREV ₀ is basically determined in step # 23.
Is executed (executed only once in one downshift) and is the turbine speed at the time when the turbine speed starts to increase by the downshift operation.

In the control routine of steps # 5 to # 9 and steps # 22 to # 23, in step # 5, the previous shift down flag SFTDWN
(i-1) is 0 and the current downshift flag SF
It is determined whether or not TDWN (i) is 1, that is, whether or not TDWN (i) is the first time after downshifting is started.
If it is the first time (YES), in step # 6, it is determined whether the vehicle speed VSP is less than the predetermined value VSP1 and whether the torque converter speed ratio TREV / NE in the initial stage of downshifting is less than the predetermined value E1. . Here, VSP <VS
If P1 and TREV / NE <E1 (YES), torque down control when the torque converter speed ratio is small,
That is, since the torque down control for starting the torque down from the initial stage of the shift down is performed, the predetermined value T ₁ is set in the torque down inhibition timer CXE in step # 7.
Is set. Here, the torque down control is
The reason for limiting the vehicle speed at low speed running such that VSP <VSP1 is that the kinetic energy of the vehicle body is large at the time of high speed running, so even if torque is suddenly transmitted from the engine 1 side to the transmission gear mechanism 3 side, the vehicle body speed is limited. Is hardly changed, so that a shift shock is unlikely to occur. On the other hand,
In step # 6, VSP ≧ VSP1 or TREV / NE
If it is determined that .gtoreq.E1 (NO), the torque-down control in the case where the torque converter speed ratio is large, that is, the torque-down control for starting the torque-down from the middle stage of the torque-down, is performed, so that step # 7 is skipped. I do.

In step # 8, the turbine rotational speed TREV (i) at this time is temporarily changed at the start of turbine start TR
Stored as EV ₀ . This TREV ₀ is a temporary value and is used for backup in the event that step # 23 described below fails. At the time of the downshift, step # 22 is executed after step # 5 from the second time.
Then, in step # 22, it is determined that the previous turbine speed change rate VTREV (i-1) is negative and the current turbine speed change rate VTREV (i) is larger than a predetermined value VTREV1 (a value equal to or greater than 0). (YES), that is, when the turbine speed TREV starts to substantially increase
(Figure 7, time t ₃ is in FIG. 8), step # 23 once is executed, the turbine speed TREV of this time (i) is stored as the real change start turbine speed TREV _0. Based on this TREV ₀ , in step # 9, equation 1
According to equation 2, the torque reduction start turbine speed XTREV
1 is calculated.

In step # 10, it is determined whether or not the torque down prohibition timer CXE (i) is larger than 0. Here, if CXE (i)> 0 (YES), torque down control is performed when the torque converter speed ratio is small (TREV / NE <E1). Hereinafter, the torque down control when the torque converter speed ratio is small will be described. In this case, in step # 11, CXE (i) is decremented by one each time, and in step # 12, the previous torque-down prohibition timer CXE (i-1) is positive and the current torque-down prohibition timer CXE (i) ) when is determined to be 0 (YES), i.e. when the torque reduction starts after T ₁ has elapsed, the torque down flag XET in step # 13
R is set to 1 and torque down is started. In this way, as also shown in FIG. 7, the shift-down after the start T ₁ has passed since the beginning torque down from t ₂ to starts, wherein since CXE is zero, always the next No is determined in step # 10, and steps # 24 to # 26 are executed (partially skipped depending on conditions). In this case, (YES) once step # 26 when it is determined that the TREV> XTREV1 in step # 25 is executed, with a predetermined value T ₂ is set to the torque-down end timer CRE, switching flag XY 1 is set. In addition,
The switching flag XY is a flag for skipping Step # 25 to Step # 26 from the next time when Step # 26 is executed once. Here, the torque-down end timer CRE is from the time when a TREV> XTREV1, used to terminate the torque down upon lapse of time T _2.

Steps # 14 to # 17 are performed in the TR
EV> XTREV1 (at time t in FIG. 7)
₄₎ 0 to torque down flag XETR after a time T ₂ has elapsed
This is a control routine for returning to. Specifically, step # 1
If it is determined at 4 that the torque-down end timer CRE (i) is positive (YES), CRE (i)
Is decremented by one, and in step # 16, the CRE is decremented.
When it is determined that (i) has reached 0 (YES), the torque down flag XETR is returned to 0 in step # 17. If it is determined in step # 14 that CRE (i) ≦ 0 (NO), steps # 15 to # 17 are skipped.

In step # 18, it is determined whether the torque down flag XETR is 1 or not.
If = 1 (YES), a torque-down signal is output in step # 19, the torque is reduced by retarding the ignition timing, and then the normal shift control is performed in step # 20. Return to 2. On the other hand, XE
If TR = 0 (NO), step # 19 is skipped, that is, the torque is not reduced, and step # 2 is not performed.
0, only normal shift control is performed.
Return to 2.

[0039] That is, in this case a TREV / NE <E1, i.e. torque input to the transmission gear mechanism 3 is relatively large in this case, as shown in FIG. 7, the shift-down at time t ₁ Time T
_At time t ₂ (the initial stage of downshifting), the torque down is started at a delay of ₁ and the turbine speed increases to TREV / NE
<Torque down is stopped from the time t ₄ when became E1 at time t ₅ after T ₂ has elapsed. As described above, in the case where TREV / NE <E1 at which the torque input to the transmission gear mechanism is large, and therefore the thrust is strong, the start timing of the downshift is set to the initial stage of the downshift, so that the strong downshift is performed. Is effectively suppressed,
The occurrence of a shift shock is prevented. The torque down may be started at the same time as the shift down is started.
(I.e. T ₁ is set to 0). In this embodiment,
At the end torque down, but be stopped at once torque reduction at time t _5, from time t _5, the ignition timing retard amount gradually or stepwise changed, so as to terminate gradually torque reduction Is also good.

Hereinafter, when the torque converter speed ratio is large (TR
EV / NE ≧ E1), that is, the torque down control when the torque input to the transmission gear mechanism 3 is small will be described. In this case, as described above, Step # 7 is not executed, and CXE is always set to 0. Therefore, NO is always determined in Step # 10. Therefore, Steps # 24 to # 26 are executed (partially skipped depending on the conditions). At this point, the torque down flag XETR is set to 0, so that TR # is set at Step # 25.
EV> XTREV1 (YES), step # 26
In after a predetermined value T ₂ is set to CRE, Step # 1
3 is executed, the torque down flag X
ETR is set to 1. That is, TREV> XTR
Initiated torque reduction after the timing when the EV1 (time t ₄ in FIG. 8). Incidentally, the torque down, as if the torque converter speed ratio is small, is stopped when the elapsed T ₂ from the time when a TREV> XTREV.

[0041] That is, in this case a TREV / NE ≧ E1, i.e. in this case the torque input to the transmission gear mechanism 3 is relatively small, as shown in FIG. 8, the shift-down at time t ₁ Is started, the turbine rotation speed rises and TREV> XTREV1 at a time t ₄
Started the torque down from (torque down metaphase), torque down at time t ₅ after T ₂ after this is stopped. Thus, the torque input to the transmission gear mechanism is small,
Therefore, TREV / NE is not so strong
If ≧ E, the shift-down start timing is set to the middle stage of the shift-down, so that the appropriate torque-down according to the input torque to the transmission gear mechanism 3 is performed, the thrust is suppressed, and the shift shock is generated. Is prevented.

In short, in this embodiment, the follow-up state of the input torque to the transmission gear mechanism 3 with respect to the change in the throttle opening, that is, the change in the engine load is grasped by the torque converter speed ratio TREV / NE, and the torque is reduced based on the follow-up state. Is changed so that an appropriate torque reduction corresponding to the input torque to the transmission gear mechanism 3 is performed. In this embodiment, the follow-up state of the transmission gear mechanism 3 with respect to the change in the engine load, that is, the change in the throttle opening is grasped by the torque converter speed ratio TREV / NE, but the rate of change of the throttle opening TVO with respect to time ( The differential value) dTVO / dt may be used. In this case, in step # 6, the dTV
It is determined whether O / dt is smaller than a predetermined value N or not.
If TVO / dt <N, the engine output follows the change in throttle opening, so that step # 7 is executed, and dTV
If O / dt ≧ N, no tracking is performed, so that step # 7 may be skipped.

It is to be noted that the torque reduction is performed not by changing the ignition timing as in the present embodiment but by changing the fuel injection amount of the fuel injection valve 11, for example, by stopping the fuel supply to all or some of the cylinders. May be performed.

[0044]

According to the control apparatus for an engine and an automatic transmission according to the first invention of the present application, when the speed ratio representing the input / output characteristics of the torque converter is smaller than a predetermined value, that is, the transmission mechanism of the automatic transmission. When the torque input to the motor is large and the thrust is strong, the start timing of the torque down is set earlier than when the speed ratio is smaller than the predetermined value. Is effectively suppressed, and the occurrence of a shift shock is prevented.

According to the control device for the engine and the automatic transmission according to the second aspect of the present invention, when the speed ratio representing the input / output characteristics of the torque converter is smaller than a predetermined value, that is, the speed ratio is input to the transmission mechanism of the automatic transmission. When the torque is large and the thrust is strong, the start timing of the torque down is set at the beginning of the downshift,
A strong torque reduction is performed, the thrust is effectively suppressed, and the occurrence of a shift shock is prevented.

According to the control device for the engine and the automatic transmission according to the third invention of the present application, basically, the same operation and effect as in the case of the second invention of the present application can be obtained. Furthermore, since the start of the torque down is delayed for a predetermined time after the start of the downshift, a state in which the longitudinal acceleration of the vehicle body suddenly decreases immediately after the start of the downshift,
The occurrence of so-called pull-in is suppressed (not promoted).

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of an engine / automatic transmission assembly (power plant) provided with a control device according to the present invention.

FIG. 2 is a schematic diagram of a torque transmission mechanism of the automatic transmission.

FIG. 3 is a conceptual diagram of a hydraulic control mechanism of the automatic transmission.

FIG. 4 is a shift map of the automatic transmission, showing shift conditions as a function of a throttle opening and a vehicle speed.

FIG. 5 is a part of a flowchart showing a control method of torque down control at the time of downshift.

FIG. 6 is a part of a flowchart showing a control method of torque down control at the time of downshift.

FIG. 7 is a diagram illustrating characteristics of a turbine speed, an engine speed, and a torque down signal with respect to time during downshifting when the torque converter speed ratio is less than a predetermined value.

FIG. 8 is a diagram showing characteristics of a turbine speed, an engine speed, and a torque down signal with respect to time during downshifting when the torque converter speed ratio is equal to or more than a predetermined value.

[Explanation of symbols]

 PT: Power plant T: Automatic transmission 1 ... Engine 3: Transmission gear mechanism 9: Spark plug 11: Fuel injection valve 13: Distributor 18: Throttle valve 57: Engine control unit 58: Transmission control unit

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Okamoto 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (56) References JP-A-2-3545 (JP, A) JP-A-1 -261558 (JP, A) JP-A-3-81538 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 29/00 B60K 41/06

Claims (3)

(57) [Claims] An engine and a control device for an automatic transmission provided with a torque changing means for reducing the torque of the engine during a shift operation of the automatic transmission, based on a state in which the transmission input torque follows a change in engine load. Timing change means for changing the timing of torque down by the torque change means is provided, and the timing change means determines a follow-up state of the transmission input torque with respect to an engine load change based on an input / output characteristic of the torque converter at the beginning of a shift. When the speed ratio representing the input / output characteristics is smaller than a predetermined value,
A control device for an engine and an automatic transmission, wherein torque reduction is started earlier than when the speed ratio is larger than the predetermined value. 2. A control device for an engine and an automatic transmission provided with a torque changing means for reducing the torque of the engine at the time of shifting of the automatic transmission, based on a state in which the transmission input torque follows a change in engine load. Timing change means for changing the timing of torque down by the torque change means is provided, and the timing change means determines a follow-up state of the transmission input torque with respect to an engine load change based on an input / output characteristic of the torque converter at the beginning of a shift. When the speed ratio representing the input / output characteristics is smaller than a predetermined value,
A control device for an engine and an automatic transmission, wherein torque reduction is started before a turbine rotation starts to increase after a shift command. 3. The control device for an engine and an automatic transmission according to claim 2, wherein the timing changing means delays the start of the torque reduction for a predetermined time after the start of the downshift. Engine and automatic transmission control device.