JPH0581452B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a shift control method for an automatic transmission for a vehicle, and in particular, a main transmission that can automatically change gears in relation to at least vehicle speed and engine load;
An automatic transmission for a vehicle, comprising an auxiliary transmission capable of automatically switching between at least a low speed side and a high speed side, and achieving multi-speed shifting by simultaneously or alternately shifting the main transmission and the auxiliary transmission. This invention relates to improvements in the speed change control method for aircraft.

[Conventional technology]

In an automatic transmission for a vehicle, when the number of gears achieved is increased, the amount of fluctuation in engine rotational speed during gear shifting is reduced, so the amount of energy that the frictional engagement device must absorb is reduced, and the frictional engagement The durability of the device can be improved, and torque fluctuations during gear shifting (shift shock) can be reduced. Conventionally, in order to increase the number of gears achieved and to reduce design changes to existing automatic transmissions and to provide manufacturing advantages, gears may be automatically shifted at least in relation to engine load. Based on the existing automatic transmission, this is used as the main transmission, and an auxiliary transmission that can automatically switch between the low speed side and the high speed side independently of the main transmission is connected in series on the power transmission system. There is an automatic transmission that achieves a large number of gears by arranging the gears in the gears. For example, an overdrive device (O/D) that automatically switches between overdrive as a high speed gear and non-overdrive as a low gear (non-overdrive is a reduction ratio of 1, for example) is connected to the main transmission as an auxiliary transmission. In the case of automatic transmissions connected in series to the input side or output side of It is possible to achieve 6-stage multi-stage shifting. By increasing the number of gears achieved in this way, it becomes possible to improve the durability of the frictional engagement device and reduce the shift shock during gear shifting, as described above, and also to prevent excessive load on the engine. Since the fuel consumption is eliminated, good results can be obtained in terms of fuel efficiency and power performance.

[Problems to be solved by the invention]

However, in such an automatic transmission that achieves multi-speed shifting by shifting the main transmission and the auxiliary transmission simultaneously or alternately, the effect of the friction engagement device for high gear shifting of the auxiliary transmission is It is difficult to obtain good shift characteristics for all shifts involving high gear shifts in the auxiliary transmission by simply changing the force according to the throttle opening as is done in a general upshift. There was a problem. That is, as is clear from FIG. 3, for example, the first
Shifting from gear to 2nd gear, shifting from 5th gear to 6th gear
When shifting to gear, the main transmission remains the same.
Upshifting of the entire automatic transmission is achieved only by shifting the auxiliary transmission to a high gear, but in this case, as schematically shown in Figure 4, the gear ratio on the main transmission side is higher than the former. Therefore, if a similar shift shock occurs in the friction engagement device on the auxiliary transmission side, the shift shock on the former side will be increased accordingly and will be reflected on the output side. In order to avoid this large shift shock, the acting force on the friction engagement device of the auxiliary transmission should be kept low in accordance with the shift from the first gear to the second gear. As a result, the oil pressure is lowered, and it takes an excessively long time to shift gears, which should be possible in a short time without any problems. Generally, it is not preferable to take a long time for the engagement because it will reduce the durability of the frictional engagement device. On the other hand, in the case of shifting from the first gear to the second gear, if the working oil pressure in the friction coupling device of the auxiliary transmission is kept low in order to reduce the shift shock based on the above-mentioned reason, then Since the shift time becomes longer, durability problems also arise. [Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and it is an object of the present invention to provide good shifting characteristics and good durability during all shifting operations involving high gear shifting of the auxiliary transmission. It is an object of the present invention to provide a shift control method for an automatic transmission for a vehicle that can achieve both of the above.

[Means for Solving the Problems] The present invention provides a main transmission that can automatically change gears depending on at least vehicle speed and engine load;
An automatic transmission for a vehicle, comprising an auxiliary transmission capable of automatically switching between at least a low speed side and a high speed side, and achieving multi-speed shifting by simultaneously or alternately shifting the main transmission and the auxiliary transmission. A method for controlling the speed change of an aircraft, which achieves the above object by changing the engine torque during a speed change accompanied by a high gear shift of the auxiliary transmission, and changing the amount of change in the engine torque according to at least the type of speed change. It is.

[Effect]

In the present invention, the engine torque is changed during a shift involving a high gear shift of the auxiliary transmission, and the amount of change in the engine torque can be changed at least according to the type of shift. By changing the engine torque, the shift time when shifting from the fifth gear to the sixth gear, which is less problematic, can be shortened, and the durability can be improved accordingly. Also, when shifting from the first gear to the second gear,
If the working oil pressure is kept low in order to reduce the shift shock, and as a result the shift time becomes longer and durability problems arise, it is possible to reduce the shift time by changing the engine torque. It is possible to shorten the time and improve durability. Furthermore, the following situations can also be dealt with. That is, the shift command to shift completion time is 1 to
It takes about 1.5 seconds, but the rotational speed of the automatic transmission's output shaft generally increases during this time. This rate of increase is determined by the output shaft torque of the automatic transmission, and its value is 1st gear → 2nd gear > 3rd gear → 4th gear >
5th speed → 6th speed. Therefore, if the engine rotational speed at the time of the shift command is the same, the larger the rate of increase in the output shaft rotational speed of the automatic transmission is, the higher the turbine synchronous rotational speed after the shift is completed. This means that when shifting from 1st gear to 2nd gear, the amount of change in engine speed due to gear shifting is the smallest.
This means that the amount of work of the frictional engagement device is small. Therefore, 1st speed → 2nd speed < 3rd speed → 4th speed
The workload of the frictional engagement device increases in the order of speed < 5th speed → 6th speed, and since the oil pressure level is the same, the shift time increases in this order. In the present invention, even under such circumstances, the amount of engine torque reduction is reduced from 1st gear to 2nd gear < 3rd gear to 4th gear < 5th gear to 6th gear.
By changing the speed to be faster, it is possible to deal with the problem more accurately.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 is an overall schematic diagram of an automatic transmission combined with an intake air amount sensing type electronic fuel injection engine for an automobile, to which the present invention is applied. Air taken in from the air cleaner 10 is sent to an air flow meter 12, a throttle valve 14, a surge tank 16, and an intake manifold 18 in sequence. This air is mixed with fuel injected from the injector 22 near the intake port 20, and
Further, the fuel chamber 26A of the engine main body 26 via 4
sent to. Exhaust gas generated as a result of combustion of the air-fuel mixture in the combustion chamber 26A passes through the exhaust valve 2.
8, exhaust port 30, exhaust manifold 32 and exhaust pipe 34 to the atmosphere. The air flow meter 12 is provided with an intake temperature sensor 100 for detecting intake temperature. The throttle valve 14 rotates in conjunction with an accelerator pedal (not shown) provided at the driver's seat.
This throttle valve 14 is provided with a throttle sensor 102 for detecting its opening degree. Further, a water temperature sensor 104 for detecting the engine cooling water temperature is disposed in the cylinder block 26B of the engine main body 26, and a water temperature sensor 104 for detecting the oxygen concentration in the collecting part of the exhaust manifold 32 is disposed in the collecting part of the exhaust manifold 32. An O ₂ sensor 106 is provided. Further, the distributor 38 having a shaft rotated by the crankshaft of the engine body 26 is provided with a crank angle sensor 108 for detecting a crank angle from the rotation of the shaft. The automatic transmission also includes a vehicle speed sensor 11 for detecting the vehicle speed from the rotational speed of its output shaft.
0 and a shift position sensor 112 for detecting the shift position. Each of these sensors 100, 102, 104, 1
The outputs of 06, 108, 110, and 112 are input to an engine computer (hereinafter referred to as ECU) 40. The ECU 40 calculates the fuel injection amount using input signals from each sensor as parameters, and controls the injector 22 to inject fuel for a predetermined time corresponding to the fuel injection amount. Note that an idle rotation control valve (ISCV) 42 is provided in the circuit that communicates the upstream side of the throttle valve 14 and the surge tank 16, and the ECU 40
The idle speed is controlled by a signal from the engine. On the other hand, the transmission section of the automatic transmission in this embodiment includes a torque converter 910,
It includes a sub-transmission 912 and a main transmission mechanism 914 with three forward speeds and one reverse speed. The torque converter 910 includes a pump 91
6, turbine 918, stator 920 and lock-up clutch 921.
Pump 916 is coupled to engine crankshaft 922 and turbine 918 is coupled to turbine shaft 924. The turbine shaft 924 is the output shaft of the torque converter 910 and also serves as the output shaft of the auxiliary transmission 9.
12, and is connected to a carrier 926 of a planetary gear device in the auxiliary transmission 912. In the sub-transmission 912, this carrier 92
A planetary pinion 928 rotatably supported by a sun gear 930 and a ring gear 9
It meshes with 34. Further, a clutch C ₀ and a one-way clutch F ₀ are provided between the sun gear 930 and the carrier 926, and a housing surrounding the sun gear 930 and the sub-transmission 912 is provided.
A brake _B0 is provided between the brake and the Hu. A ring gear 934 of the sub-transmission 912 is connected to an input shaft 936 of the main transmission mechanism 914,
A clutch C ₁ is provided between the input shaft 936 and the intermediate shaft 938. The main transmission mechanism 914 is provided with two rows of planetary gears, one on the front side and the other on the rear side. The front planetary gear device has a sun gear 9 provided on a sun gear shaft 940 common to the front and rear sides.
42, a planetary pinion 944 that meshes with the sun gear 942, and the planetary pinion 244.
a carrier 946 that rotatably supports the ring gear 9, and a ring gear 9 that meshes with the planetary pinion 944.
48. The rear planetary gear device includes a planetary pinion 950 that meshes with the sun gear 942, and a carrier 952 that rotatably supports the planetary pinion 950.
and a ring gear 954 that meshes with the planetary pinion 950. A clutch _C2 is provided between the input shaft 936 and the sun gear shaft 940. Further, a ring gear 948 in the front planetary gear device is connected to the intermediate shaft 938. Further, the carrier 946 in the front planetary gear device is connected to a ring gear 954 in the rear planetary gear device, and the carrier 946 and ring gear 954 are connected to an output shaft 956. or,
A brake B ₃ and a one-way clutch F ₂ are provided between the carrier 952 and the housing Hu in the rear planetary gear set. Further, a brake B ₂ is connected between the sun gear shaft 940 and the housing Hu via a one-way clutch F ₁ .
A brake _B1 is provided between the sun gear shaft 940 and the housing Hu. This automatic transmission includes a transmission section as described above, and receives signals from a throttle sensor 102 that detects the throttle opening that reflects the load condition of the engine body 26, a vehicle speed sensor 110 that detects vehicle speed, etc. The input central processing unit (ECU) 40 drives and controls the electromagnetic solenoid valves S ₁ to _{S 4} in the hydraulic control circuit 60 according to a preset shift pattern, as shown in part B of FIG. Shift control is performed by combining the couplings of each clutch, brake, etc., as shown in FIG. In addition, in Fig. 3, the ○ mark indicates the operating state,
Further, the △ mark indicates that the brake is activated only when the engine brake is in use, and the × mark indicates that the brake is activated only when the engine brake is used. The electromagnetic solenoid valves S ₁ and S ₂ control the speed change of the main transmission 914, and the electromagnetic solenoid valve S ₃ controls the high-speed side and low-speed side of the sub-transmission 912. _S4 controls the lock-up clutch 921 of the torque converter 910, respectively. In such a device, the ECU 40 includes:
Upon receiving the shift information (shift determination, shift command, lock-up clutch engagement permission, etc.) from the ECT computer 50, it executes engine torque down control and transmits this control information to the ECT computer 5.
Output to 0. Based on this information, the ECT computer 50 issues a lock-up clutch release command and checks whether the above control is being performed reliably. In this embodiment, the ECU 40 and the ECT computer 50 are separate units, and the ECU 40 determines and executes the amount and timing of engine torque down. However, in the present invention, the number of control devices or their control areas It is not limited to. Next, the operation of this embodiment will be explained using FIG. First, in step 300, a shift decision is made in accordance with the vehicle speed, engine load (throttle opening degree), etc., as in the conventional case. When the gear shift determination is made, it is determined in step 302 whether or not the gear shift determination is a gear shift in which the auxiliary transmission 912 is engaged (however, this step does not actually exist as one step). do not have). When it is determined that the gear change is one in which the sub-transmission 912 is engaged, the process proceeds to step 304 where the electromagnetic solenoid valve _S3 is turned on, and at the same time, in step 306, the timing for starting torque reduction of the engine is detected. Monitoring of the engine rotational speed Ne starts. As a result of this monitoring, when it is determined in step 308 that the currently measured engine rotational speed Nei is smaller than the previously measured engine rotational speed _Nei-1 , engine torque reduction is started. At this time, first, in step 310, it is confirmed what type of shift was determined in step 300. As a result, when it is confirmed that a shift from 1st gear to 2nd gear has been determined, the engine torque is reduced by 20% in step 312, and similarly, when shifting from 3rd gear to 4th gear, the engine torque is reduced by 20%. When it is confirmed that the torque has increased, the torque is reduced by 40% in step 314.
Further, when it is confirmed that the gear has changed from the fifth gear to the sixth gear, the torque is reduced by 60% in step 316. These torque reductions are continued in step 318 until the engine rotational speed Nei becomes smaller than the value obtained by multiplying the output shaft rotational speed _N0 of the automatic transmission by the gear ratio _IH plus the constant _N1 , When the torque becomes smaller, the torque is restored in step 320. Note that steps 402 and 404 are
Stop the flow until conditions 308 and 318 are met.
This shows the flag setting steps to maintain the state. As long as these conditions are not met, flag F is set to 1 or 2 and then reset, and then the flag is reset through steps 401 and 403 in the flow. Each flow is configured to proceed directly before each flow. Note that these flags 1 or 2 are reset to zero in step 405. Next, the effectiveness of this embodiment will be explained using the speed change transient characteristic diagram shown in FIG. The two-dot chain _line
6 shift). The oil pressure level at this time was P _B0 , and there were no problems with the gear shifting shock or durability. If a six-speed 1-2 shift is performed at the same oil pressure level, a very large shift shock will occur as shown by the two-dot chain line _Y1 in the figure. This is because, as described above, fluctuations in the output shaft torque of the auxiliary transmission are greatly amplified by the first gear ratio of the main transmission. Therefore, in order to reduce the shift shock to an acceptable level in an automatic transmission that achieves multi-speed shifting by shifting the main transmission and the auxiliary transmission simultaneously or alternately, it is necessary to adjust the oil pressure level as shown in the figure. must be reduced to the level of P _B0 ′. When the oil pressure level is lowered to the level of P _B0 ′, 1 → 2
The gear shift shock during shifting is shown by the dashed line _Y2 in the figure. However, when the oil pressure level is lowered in this way, although the shift shock can be made smaller, the shift time is extended to _t1 , which increases the amount of energy absorbed and causes problems in terms of durability.
A first requirement arises that the engine torque should be reduced during gear shifting to shorten the gear shifting time.
Therefore, in the above embodiment, when shifting from 1 to 2,
Reduce the torque by 20% and change the gear shift time from _t1.
It is reduced to t ₃ (dashed line Y ₃ ). On the other hand, by reducing the oil pressure level from P _B0 to P _B0 ', the shift time during the 5th to 6th shift, which had no problem with the shifting mechanism, was extended to t ₂ as shown by the dashed line X ₂ . A situation arises where this happens.
The reason why t ₂ is longer than t ₁ is as follows. That is, in the member rotation speed column, the increase rate of the output shaft rotation speed N ₀ of the automatic transmission is 1 → 2>
It goes from 5 to 6. This is because the output shaft torque levels before and after the shift are different. Therefore, if the turbine rotational speed N _T at the start of gear shifting is the same, the output shaft rotational speed _N
→Turbine synchronous rotation speed n ₀ ' during 2nd shift is 5→
The turbine synchronous rotation speed during the 6th shift is higher than n ₀ (t ₁ if there is no increase in the output shaft rotation speed N ₀
= t ₂ ). As a result of these, regarding the 5th to 6th shift, even though there is no problem with the gear shifting mechanism, 1 in Figure 1.
As shown by the dotted chain line X ₂ , shifting takes an extremely long time t ₂ , so in order to improve durability, it is necessary to significantly reduce the torque and significantly reduce the shifting time to improve durability. A second request arises. Therefore, in the above embodiment, by reducing the torque by 60% during the 5th to 6th shift, the shift time is shortened from _t2 to _t4 , as shown by the broken line in the figure. Dashed line X ₃ ). Regarding the 3→4 shift, which is considered to be in an intermediate position based on the first and second requests,
Torque is reduced by 40% to balance the effects of both. In the above embodiment, the success or failure of Nei<Ne _i-1 is used as the condition for starting torque down, and the success or failure of Nei<N ₀ ×I _H +N ₁ is used as the condition for torque restoration. However, in the present invention, the timing of starting engine torque change or the method of setting the return time is limited. It's not a thing.

【Effect of the invention】

As explained above, according to the present invention, during a shift involving a high gear shift of the auxiliary transmission, torque reduction control is performed by a different amount for each shift, thereby improving durability and improving durability for each shift. An excellent effect can be obtained in that it is possible to purposefully achieve both the reduction of the shift shock and the reduction of the shift shock.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment of a speed change control method for an automatic transmission for a vehicle according to the present invention, and FIG. 2 is an electronic fuel injection engine for an automobile with an intake air amount sensing type for realizing the above embodiment. FIG. 3 is a diagram showing the state of engagement and combination of the frictional engagement device in the automatic transmission, and FIG. 4 is a diagram showing the gear change in the automatic transmission. A schematic block diagram to show the state of occurrence of shock,
FIG. 5 is a speed change transient characteristic diagram in the above embodiment. 26...Engine body, 912...Sub-transmission,
914...Main transmission, _S3 ...Sub-transmission control electromagnetic solenoid valve, 40...Engine computer, 50...ECT computer.

Claims (1)

[Scope of Claims] 1. A main transmission capable of automatically switching gears in relation to at least vehicle speed and engine load, and a sub-transmission capable of automatically switching at least a low speed side and a high speed side, In the shift control method for a vehicle automatic transmission, which achieves multi-speed shifting by simultaneously or alternately shifting the main transmission and the auxiliary transmission, the engine torque is reduced during a shift accompanied by a high gear shift of the auxiliary transmission. 1. A method for controlling a shift in an automatic transmission for a vehicle, characterized in that the amount of change in the engine torque is changed in accordance with at least the type of shift.