JPH0828674A - Method for gear shift of transmission for vehicle - Google Patents

Abstract

PURPOSE:To provide a transmission method which dispenses with a transmission schedule map required for the transmission of a conventional vehicle, and suppresses the capacity of a memory element, etc., to the minimum. CONSTITUTION:The turbine torque Tt in the present gear step is estimated by a block 1 relative to the throttle opening TVO when a driver steps in an accelerator pedal, and compared with the critical turbine torque Tt1m by a block 2 to judge the transmission. This operation is repeated until entering the condition of Tt<Tt1m, and when the condition Tt< Tt1m is met, the gear step in the block 1 is outputted. The transmission point is operated on the real time basis according to the engine load such as the throttle opening, the running condition of a vehicle, or the traveling condition of the vehicle, and the capacity of the memory element, etc., can be suppressed to the minimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shifting method for an automatic transmission, and more particularly to a shifting method for a vehicular transmission which is capable of realizing shifting without a shift schedule map by calculating shift points. is there.

[0002]

2. Description of the Related Art Conventionally, the shifting method of an automatic transmission has been tuned from a comprehensive aspect of fuel consumption characteristics and acceleration characteristics.
The shift schedule map was written in the storage element in advance and the shift was performed in accordance with the map. Here, JP-A-54
As shown in Japanese Patent Publication No. 5167, the shift line is defined by the load and the engine speed, and only the broken points approximate to the polygonal line are stored and read out and stored. The transmission line of the transmission can be changed according to the target torque. As shown in JP-A-1-238748, data such as accelerator pedal operation amount, brake operation amount, steering wheel operation amount, vehicle speed, etc. can be used according to road conditions. , Which determines the driving characteristics of the driver and selects a shift pattern suitable for the driver, as disclosed in Japanese Patent Laid-Open No. 62-246655, a corrected vehicle speed which is a function of the vehicle speed. It has been necessary to calculate and based on the corrected vehicle speed, several shift schedule maps used under each traveling condition and the like are written in the storage element in advance.

[0003]

The shift schedule map setting method described above is a shift schedule that is set in a unified manner by making adjustments from the overall aspects of fuel consumption characteristics, acceleration characteristics, etc., as described above. Moreover, tuning the shift schedule map took a lot of time.

Further, the shift schedule map does not take into account the individual preferences of the automobile user, driving and running conditions, that is, the shift schedule based on the acceleration characteristic and the engine braking characteristic, and the user writes it in the storage element in advance. Had to follow the map that is. Therefore, the problem to be solved by the present invention from the above-mentioned conventional technique is that the engine does not have a shift schedule map, and the engine load such as the throttle opening, the operating state or running state of the vehicle, and the shift point according to the user's request are set. It is an object of the present invention to provide a gear shift method for a vehicle transmission which is capable of being calculated in real time and being capable of driving, traveling, etc., of the vehicle based on the gear shift point.

[0005]

In order to achieve the above object, a means and an engine for measuring at least an engine load such as a throttle opening, a vehicle speed, a driving state of a vehicle such as a gear stage or a gear ratio, or a running state of the vehicle. A means for storing characteristics of the vehicle such as output characteristics and torque converter characteristics is provided, and a signal measured by the means is used to calculate the shift point of the transmission in real time to change the gear ratio of the vehicle. The task can be achieved.

[0006]

According to the present invention having the above-mentioned means, at least the engine load such as the throttle opening, the vehicle speed, the driving state of the vehicle such as the gear stage or the gear ratio, or the running state of the vehicle is measured,
Since the shift point of the transmission is calculated in real time according to the signal measured by the means, the shift schedule map that was conventionally required for shifting the vehicle becomes unnecessary, and the shift element such as the storage element that has written the shift schedule map becomes unnecessary. The capacity can be minimized, the manufacturing cost can be reduced, a large amount of time spent for tuning the shift schedule map can be eliminated, and the driving or running condition of the vehicle and the user's request It is possible to configure a shift method of a vehicle transmission that enables traveling at a shift point according to

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 2 is a system configuration diagram of a power train to which the present invention is applied. The output of the engine 3 is torque-amplified by a torque converter 5 in a stepped automatic transmission (AT) 4 and given to a gear train 6. The output of the engine 3 is passed through a propeller shaft 7 and a differential gear 8 which also serves as a final reduction gear. 9
It is transmitted to. 10 is an AT with a built-in microcomputer
4 control unit (electronic control unit: A here)
It is referred to as TCU). ATCU10 has a vehicle speed sensor 1
1, signals from a turbine rotation sensor 12, an AT oil pressure sensor, etc., and an engine rotation signal, a throttle opening signal, etc., from an engine control unit (electronic control unit: herein referred to as ECU) 13 are input, and various calculations are performed. Is executed to output the valve drive signals of the hydraulic control solenoid valves 15 (a) and 15 (b) mounted on the hydraulic circuit 14 of the AT. Information such as a crank angle sensor, an air flow sensor 16 for measuring the amount of intake air, and a throttle sensor 18 in a throttle controller 17 is input to the ECU 13,
The engine rotation signal and other calculations are executed to execute various controls.

FIG. 3 illustrates an ATCU1 for implementing the present invention.
0 shows the configuration of a zero microcomputer. Signals from various sensors are converted into digital signals by the input processing unit 19 and C
It is sent to the PU 20. CPU 20 receives the input signal and RO
The calculation and condition determination are performed using the control constants stored in M21, and the result is sent to the output processing unit 22. The output processing unit 22 converts the voltage to drive the hydraulic control solenoid valve 15. In the calculation process of the CPU 20, according to the method of the present invention, the engine output characteristic map 23 and the torque converter characteristic map 24 are stored in the ROM 21, the operating point of the engine is sequentially calculated, and the shift turbine torque is calculated and compared with the limit turbine torque. The characteristic feature is that the optimum shift point is calculated by doing this.

FIG. 1 is a block diagram showing a first embodiment of the present invention. Throttle opening TVO when the driver depresses the accelerator pedal (a signal that clearly indicates the engine state, such as accelerator pedal opening, intake air amount, injector pulse width, engine speed, engine torque, etc. (The opening signal is an example), the turbine torque Tt in the current gear stage is estimated in block 1, and in block 2 the shift judgment is performed by comparing with the limit turbine torque Ttlm. As a result, if the condition is Tt ≧ Ttlm, it is determined that the gear has been shifted to the next lower gear, the gear is set to a speed lower by one than the current gear, the turbine torque Tt is calculated in block 1, and the block 2 is calculated. The shift determination is performed by comparing with the limit turbine torque Ttlm. This operation is repeated until the condition of Tt <Ttlm is satisfied, and Tt <
When the condition of Ttlm is entered, at this time, that is, the gear stage in block 1 is output. This operation will be described with reference to FIG. FIG. 4 shows the turbine rotation speed Nt at a certain throttle opening TVO (a signal example that clearly shows the engine state).
3 shows a limit turbine torque Ttlm curve for the. Shift determination is performed based on the magnitude of Tt and Ttlm with respect to Nt at a TVO. As a result of performing simulations and various experimental studies, this Ttlm has a gear stage n,
That is, regardless of whether the shift is from the fourth speed to the third speed, the third speed to the second speed, or the second speed to the first speed, TVO and N
It became clear that it was decided by t. That is, the functional expression of Ttlm = f (TVO, Nt) is established. Therefore, this functional expression is used, or this functional expression is mapped and stored in advance, and TVO and Nt at that time are stored.
To calculate Ttlm or extract by searching,
Shift determination is performed by comparing with Tt. If the vehicle speed is constant from the current TVO position (provisionally, the current gear n is the fourth speed) and the vehicle speed is constant after the gear shift, the turbine torque Tt _4A is calculated when the TVO is depressed to the position (A). A comparison is made with the limit turbine torque Ttlmn at point (B). As a result, A
At the position of the point, since Tt _4A <Ttlmn, n holds the fourth speed. Then TVO to the position of point (C)
When stepping on, when the turbine torque Tt _4C is calculated, Tt _4C ≧ Ttlmn, so n should be shift-changed to the third speed, which is a gear speed one step lower than the current fourth speed. The speed change signal is not output. Before that, Tt ₃ and Nt ₃ are calculated with n being the third speed (as described above, since Vsp is a constant condition even after the gear shift, the calculated Tt ₃ is a value which takes into account the gear ratio, and Nt ₃ The same applies), and the value is at point (D) or point (F). First, if Tt ₃ is point (D),
Since t _3D <Ttlmx, the gear shift signal for the third speed is output for the first time. On the other hand, when Tt ₃ is the (F) point, Tt _3F ≧ Ttlmx, so that Tt ₂ and Nt ₂ are calculated by setting n to be the second speed, which is one speed lower than the third speed. If the ideal gear is selected and a shift signal is output by repeating the above-mentioned method every fixed time, skip shifting (for example, from 4th gear to 2nd gear)
Even when the gear is in the (high speed), it does not enter the gear stage between them, so the torque fluctuation during the gear shift is small and the gear shift time is short.

FIG. 5 shows the method of FIG. 1 in detail. N and x attached to each signal mean the value of the current gear and the value of the gear on the x-speed lower side than the current gear. Throttle opening signal T from the throttle sensor 18
VOn (an example of a signal that clearly indicates the engine state) and EC
The engine torque Ten is obtained by comparing the engine rotation signal Nen from U13 with the engine output characteristic 23. On the other hand, the turbine speed Ntn is obtained by multiplying the vehicle speed signal Vspn by the gear ratio gn. Therefore, the speed ratio e is calculated from this and Nen, and the torque ratio tn is obtained by referring to the torque converter characteristic 24. From this, the turbine torque Ttn is calculated. Then, from the relationship 25 between the limit turbine torque Ttlm and the turbine speed Nt described in FIG. 4, the limit turbine torque Ttlmn for Ntn at TVOn is extracted, and the turbine torque comparison processing unit 2 is extracted.
The comparison with the previously obtained Ttn is performed. Here, the condition Tt
When n ≧ Ttlmn is not established, the current gear stage n is held, and when the above condition is established, the gear stage is a gear on the x stage lower speed side (here, x = 1) than the current gear stage n. As a stage, the block 2 is used under the condition that the vehicle speed Vsp is constant immediately after the gear shift
The process of 6 is performed. For this, the current Vspn is multiplied by the gear ratio x on the x stage lower speed side than n (here, x = 1) to obtain the turbine speed Ntx. Here, the speed ratio ex of the torque converter that balances the turbine rotational speed with Ntx is obtained by maintaining the same throttle opening TVO (an example of a signal that clearly indicates the engine state) even after shifting. Therefore, a Ne map 27 in which the relationship between the engine speed Ne and the TVO and the speed ratio e is calculated in advance is provided. When a certain speed ratio ex is given, the engine speed Nex is calculated from the Ne map 27, and the correction value Δe is added to ex until it becomes equal to Ntx previously calculated in the turbine speed comparison processing unit 28, and the calculation is repeated. I do. Nt
Using the speed ratio ex when x2 and Ntx are equal,
By comparing the torque ratio tx from the torque converter characteristic 24 and the engine speed Nex and TVOn at this time with the engine output characteristic 23, the engine torque Tex is estimated, and the two are multiplied to calculate the turbine torque Ttx. Then, the limit turbine torque Ttl described in FIG.
From the relation 25 between m and turbine speed Nt, N at TV On
extract the limit turbine torque Ttlmx for tx,
The turbine torque comparison processing unit 2 compares with Ttx previously obtained. Here, when the condition Ttlmx> Ttx is satisfied, x gear lower speed side than the current gear (here, x = 1)
The gear shift signal is output to the gear stage of the gear and the gear is shifted. Conversely, condition T
If tlmx> Ttx is not satisfied, the block 2 is set at a low speed side (x = 2 in this case) of the x-th step, and the vehicle speed Vsp is kept constant even immediately after the shift at a small fixed time interval.
The process of 6 is repeated to select the ideal gear and output the shift signal. Note that instead of providing the Ne map, e
It can also be realized by using a method of repeatedly calculating while adding the correction values Δe and ΔNe to both x and Nex and scanning the entire area. Needless to say, instead of calculating the current turbine speed from the vehicle speed and obtaining it, the turbine speed may be directly detected. According to the method of the present embodiment, the turbine torque is calculated at every minute fixed time based on the throttle opening (an example of a signal that remarkably indicates the engine state) and the turbine speed, and the turbine torque is compared with the limit turbine torque. Turbine torque> Turbine torque is repeated until the gear is changed to the low speed side until the condition is met, and the gear when the condition is met is output as a gear shift signal for gear shifting. ), It does not enter the gear stage between them, so there is little torque fluctuation during gear shifting and the gear shifting time is short.

FIG. 6 is a logic diagram showing a second embodiment of the present invention. This method divides the pattern area by taking into consideration not only the magnitude of the throttle opening TVO (example of a signal that shows the engine state prominently) but also its time change dTVO / dt. Is continuously selected to calculate the shift point. TVO or dTVO / dt, TVO or dTVO /
In the determination processing unit 29 of dt, TVO or dTV
It is determined whether the magnitude of O / dt is a preset minimum value, a preset maximum value, or a value in between, and the pattern determination processing unit 30 performs calculation. Determine the pattern of methods.
That is, if the size of TVO or dTVO / dt is the minimum value, the maximum economy pattern, if it is the maximum value, the maximum power pattern, and if it is in the middle, the economy pattern and the power pattern are weighted and combined. In practice, the calculation method is based on the pattern signal and T
The VO is determined by the TVO area determination processing unit 31.
If the pattern signal is the most economical pattern, T
The shift points are calculated by the methods (1) to (3) according to the size of the VO, and if the pattern signal is the most power pattern, the methods (4) to (6) according to the size of the TVO. The shift point is calculated in step S1. If the pattern signal is between the maximum economy pattern and the maximum power pattern, the shift pattern is calculated by weighting and combining the economy pattern and the power pattern according to the size of TVO.

Here, the calculation methods (2) and (5) in the TVO area determination processing section 31 are adapted to the first embodiment of the present invention. The first embodiment compares the turbine torque Tt at the current gear stage with the limit turbine torque Ttlm obtained from the limit turbine torque Ttlm curve with respect to the turbine speed Nt to make a shift determination.
As a result, if Tt ≧ Ttlm, it is determined that the gear has been shifted to the next lower gear, the gear is set to a speed lower by one than the current gear, the turbine torque Tt is calculated, and comparison is made with the limit turbine torque Ttlm. Then, shift judgment is performed. This operation is repeated until the condition of Tt <Ttlm is entered, and when the condition of Tt <Ttlm is entered, the gear stage at this point is output.
lm differs between the maximum economy pattern of (2) and the maximum power pattern of (5), and is set to a lower vehicle speed side than the maximum power pattern of (5) during the maximum economy pattern of (2). Set the Ttlm curve to.

Further, the calculation methods (3) and (6) in the TVO area determination processing unit 31 are such that the vehicle speed at which the engine speed Ne becomes lower than the maximum limit value of the engine speed Ne by a predetermined value,
In the calculation methods (1) and (4), the vehicle speed near the maximum engine torque in the engine output characteristic or the vehicle speed in the stall rotation range of the torque converter is stored in advance, and when these vehicle speeds are reached, the next lower speed side The gear is switched to, that is, the gear is changed.

According to the method of this embodiment, not only the throttle opening but also the change can be taken into consideration to divide the pattern area, and the shift points can be selected in real time by continuously selecting between economy and power. Since the shift point is output based on the calculated value, there is no need to map the shift schedule, which has conventionally required a great amount of time for tuning, and the number of development steps can be greatly reduced.

FIG. 7 is a block diagram showing a third embodiment of the present invention. This embodiment discloses a method of estimating the engine torque Te and the turbine torque Tt using the characteristics of the torque converter without using the engine output characteristics. The output speed of the torque converter obtained by multiplying the engine speed Nen and the current vehicle speed Vspn by the gear ratio gn of the current engagement gear stage, so-called turbine speed Ntn, is input to the block 32, and from en = Ntn / Nen, The speed ratio en of the torque converter is calculated. This en is sent to blocks 33 and 24. In block 33, the pump capacity coefficient Cn corresponding to en is extracted from the pump capacity coefficient characteristic stored in advance. Then, Cn is multiplied by Nen ₂ which is the square of the engine speed, and Te =
The engine torque Ten is calculated from Cn · Nen ₂ . On the other hand, in block 24, the torque ratio tn corresponding to en is extracted from the torque converter characteristics stored in advance. The turbine torque Ttn is obtained by multiplying both of them, that is, Ten and tn. The limit turbine torque Ttlm and the turbine speed Nt described in FIG.
From the relationship 25, the limit turbine torque Ttlmn for Ntn at TVOn is extracted and compared with Ttn previously obtained by the turbine torque comparison processing unit 2. If the condition Ttn ≧ Ttlmn is not satisfied, the current gear stage n
If the above condition is satisfied, the gear speed is set to a gear speed lower than the current gear speed n by x speed (here, x = 1), and the vehicle speed Vsp is kept constant even immediately after the gear shift. The process of block 26 is performed. For this, the current Vspn is multiplied by the gear ratio x on the x stage lower speed side than n (here, x = 1) to obtain the turbine speed Ntx. Here, it is important that the gear position n is lower than the current gear position n by a speed lower than the current gear position n (here, x
= 1), what is the speed ratio e of the torque converter? As a result of simulations and various experimental investigations, the following was revealed. That is, this speed ratio e is equal to the throttle opening TVO
And the speed change state, that is, the speed change from the 4th speed to the 3rd speed, the speed change from the 3rd speed to the 2nd speed, or the speed change from the 2nd speed to the 1st speed. That is, in the case of shifting from 4th speed to 3rd speed, ex ₄₃ = f (TV
O ₄₃ ). When shifting from 3rd speed to 2nd speed. ex ₃₂ = f (T
VO ₃₂ ). In addition, in the case of shifting from 2nd speed to 1st speed, ex ₂₁
= F (TVO ₂₁ ) is satisfied. Therefore, in block 34, the relational expression is used, or this is mapped and stored in advance, and ex is calculated from TVO at that time or extracted by retrieval. Thus, the X-stage low speed side (here, x
= 1), the expected speed ratio ex is Nt calculated previously.
Multiplying by x, the engine speed Nex on the x stage low speed side (here, x = 1) is calculated from Nex = ex · Ntx. On the other hand, in block 34, the pump displacement coefficient Cx corresponding to ex is extracted from the pump displacement coefficient characteristic stored in advance. Then, Cx is multiplied by the above-described engine speed squared Nex ₂ to obtain Te = Cx · Ne.
The engine torque Tex is calculated from x ₂ . On the other hand, in block 24, the torque ratio tx corresponding to ex is extracted from the torque converter characteristics stored in advance. The turbine torque Ttx is obtained by multiplying both of them, that is, Tex and tx. From the relationship 25 between the limit turbine torque Ttlm and the turbine speed Nt described in FIG. 4, the limit turbine torque Tt with respect to Ntx at TVOn is obtained.
lmx is extracted and compared with Ttx previously obtained by the turbine torque comparison processing unit 2. Here, the condition Ttlmx>
When Ttx is established, a gear shift signal is output to the gear gear on the x-speed lower side (here, x = 1) than the current gear gear, and gear shifting is performed. On the contrary, when the condition Ttlmx> Ttx is not satisfied, the gear stage is further set to the x-stage low speed side (here, x = 2), and the processing of the block 26 is performed every minute constant time under the condition that the vehicle speed Vsp is constant immediately after the shift. Is repeated to select the ideal gear and output the shift signal.

The turbine torque Tt estimation logic shown in FIG. 7 has the engine torque Te characteristic (the Te for the engine speed Ne stored in advance, Te,
This is a method of utilizing only the characteristics of the torque converter without using the throttle opening TVO characteristics). Therefore, as in the lean burn type engine, even in the same TVO, the air-fuel ratio A / F of the air-fuel mixture uses the theoretical air-fuel ratio A / F = 14.7 and the lean air-fuel ratio A / F = 23 to 25. There is a region, that is, even in the engine having an operating region where the engine torque is greatly different, even when the operation that transits between these two regions is performed, the torque converter input torque, that is, the engine torque, Te It has a great advantage that can be estimated. The same applies to a turbo engine, a variable intake length engine, a variable valve timing engine, a variable compression ratio engine, and a variable expansion ratio engine. Needless to say, instead of calculating the current turbine speed from the vehicle speed and obtaining it, the turbine speed may be directly detected. Further, according to the method of the present embodiment, the turbine torque is calculated at every minute fixed time based on the throttle opening (a signal example that shows the engine state remarkably) and the turbine speed, and the turbine torque is compared with the limit turbine torque. , The limit turbine torque> turbine torque is satisfied until the condition is satisfied, the gear speed is changed to the low speed side repeatedly, and the gear speed when the condition is satisfied is output as a speed change signal and the speed is changed. Even in the 2nd speed), it doesn't enter the gears in between, so
Torque fluctuations during gear shifting are small and gear shifting time is short.

[0018]

According to the present invention, at least the engine load such as the throttle opening, the engine speed, the vehicle speed, the operating state of the vehicle or the running state of the vehicle at the gear stage or gear ratio is measured, and the measured signal is output. Accordingly, the calculation method is switched in the calculation process to calculate the shift point of the transmission in real time,
Since the shift point is output based on the calculated value, it is not necessary to map the shift schedule, which has conventionally required a great amount of time for tuning, and the development man-hours can be significantly reduced, and the shift schedule map can be written. It is possible to minimize the capacity of the memory elements and the like, which can reduce the manufacturing cost, and the optimum shift point (for example, even if the torque is reduced even if the engine changes over time or the engine machine difference is met. It is possible to determine a shift point at which the same acceleration performance as that of a new product can be obtained), and it is possible to drive and run at the shift point according to the driving state or running state of the vehicle, or the user's request. In addition, even if the engine has a characteristic in which the engine torque characteristic changes extremely depending on the operating condition, such as a lean burn engine, it is possible to easily set the shift point. The same applies to engines with long specifications, variable valve timing engines, variable compression ratios, variable expansion ratio engines, etc.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a system configuration diagram of a power train to which the present invention is applied.

FIG. 3 is a configuration diagram of a microcomputer used in the present invention.

FIG. 4 is a characteristic diagram of a limit turbine torque curve.

FIG. 5 is a block diagram showing a control method at the time of shifting with a limit turbine torque.

FIG. 6 is a logic diagram showing a second embodiment of the present invention.

FIG. 7 is a block diagram showing a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Turbine torque estimation part, 2 ... Turbine torque comparison processing part, 3 ... Engine, 4 ... AT, 5 ... Torque converter, 6 ... Gear train, 7 ... Propeller shaft, 8 ... Differential device also serving as a final reduction gear, 9 … Drive wheels, 10… ATC
U, 11 ... Vehicle speed sensor, 12 ... Turbine rotation sensor, 1
3 ... ECU, 14 ... AT hydraulic circuit, 15 ... Hydraulic control solenoid valve, 16 ... Air flow sensor, 17 ... Throttle controller, 18 ... Throttle sensor.

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[Procedure amendment]

[Submission date] September 5, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshimichi Minowa 1-1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory

Claims (1)

[Claims] 1. A power train for a vehicle comprising an engine, a torque converter and a stepped automatic transmission, a means for measuring a driving state or a running state of the vehicle, a characteristic storage means for storing engine output characteristics, torque converter characteristics and the like. A shift method of a vehicular transmission, comprising a calculation means for calculating a control signal for controlling the vehicular power train by inputting the signal measured by the measuring means into the characteristic storing means, The present turbine torque is obtained from the engine output characteristic of the characteristic storage means on the basis of the determined engine speed and the engine load signal, and when it is larger than the limit turbine torque of the present gear stage, the present gear at the same throttle opening and vehicle speed is obtained. Predict the turbine torque after shifting at a gear speed lower than the gear speed and determine the limit turbine torque for that gear speed. Transmission method for a vehicle transmission, characterized in that for shifting the stepped automatic transmission when was smaller.