JP3621302B2 - Shift control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shift control device for an automatic transmission, and more particularly to a device configured to output a torque change request signal to an engine at the time of shifting.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known a shift control device for an automatic transmission configured to output a torque change request signal (torque down request signal) to an engine for the purpose of mitigating shift shock (Japanese Patent Laid-Open No. 10-018877). Etc.).
[0003]
[Problems to be solved by the invention]
By the way, a positive inertia torque is generated along with a decreasing change of the gear ratio (input shaft rotational speed / output shaft rotational speed) at the time of upshifting, and a negative inertia torque is generated with an increasing change of the gear ratio at the time of downshifting. It is known.
[0004]
Here, for example, at the time of downshift accompanying the accelerator depression from the low load state of the engine, a negative inertia torque Tinr is generated, so that the input shaft torque Tt of the transmission mechanism is positive as shown in FIG. On the other hand, the output shaft torque of the speed change mechanism turns negative, and the driver may feel a sense of deceleration (torque pulling) even though he is trying to accelerate.
[0005]
Further, at the time of upshifting accompanying the closing operation of the accelerator, the engine is driven reversely from the driving wheel side, and the input shaft torque Tt of the transmission mechanism becomes negative. However, as shown in FIG. Due to the positive inertia torque Tinr, the output shaft torque of the speed change mechanism may turn positive, causing the driver to feel acceleration.
[0006]
The conventional torque change request to the engine at the time of shifting is intended to alleviate the shifting shock, and the influence of the inertia torque as described above cannot be avoided, and the driver may feel uncomfortable. It is a thing.
[0007]
The present invention has been made in view of the above problems, and avoids reversal of the positive / negative output shaft torque due to inertia torque that occurs in association with a shift (gear ratio change), and does not give the driver a sense of incongruity. It aims to be able to do it.
[0008]
[Means for Solving the Problems]
Therefore, according to the first aspect of the present invention, the input shaft torque of the speed change mechanism and the inertia torque generated with the shift are estimated , and the result of adding the inertia torque to the positive / negative of the input shaft torque and the input shaft torque. By comparing the positive and negative with each other, it is determined whether or not the output shaft torque of the speed change mechanism is reversed with a shift. When the positive and negative of the output shaft torque is reversed , the torque being changed with respect to the engine is determined. It was configured to output a change request signal.
[0009]
According to such a configuration, the input shaft torque of the speed change mechanism is estimated as a negative torque when the engine is driven from the drive wheel side, and the inertia torque is estimated to be positive and negative according to the change direction of the gear ratio, From these input shaft torque and inertia torque, it is determined whether or not a change in engine torque is required, and a torque change request signal is output to the engine.
[0011]
That is, by adding the inertia torque to the input shaft torque, it is estimated whether the output shaft torque is positive or negative when the inertia torque is generated with a shift, and when the input shaft torque is positive, the output shaft torque is negative. Or when the output shaft torque is positive when the input shaft torque is negative, the torque positive / negative is determined to be reversed, and a torque change request signal is output to the engine at a shift where such positive / negative reversal occurs. To do.
[0012]
The negative state of the input shaft torque indicates a torque in a decelerating state where the engine is driven from the driving wheel side, not in a state where the driving wheel is driven by the engine.
According to the second aspect of the present invention, when it is determined that the sign of the output shaft torque is reversed during the upshift, a torque down request signal is output to the engine, and the sign of the output shaft torque is determined during the downshift. When it is determined to reverse, a torque up request signal is output to the engine.
[0013]
According to such a configuration, at the time of upshifting, a positive inertia torque is generated as the gear ratio (input shaft rotational speed / output shaft rotational speed) decreases, so the result of adding the positive inertia torque to the input shaft torque When it is determined that the output shaft torque is positively reversed with respect to the negative input shaft torque, a torque down request signal is output to the engine, and the output shaft torque is positive even if a positive inertia torque occurs. The input shaft torque is further reduced so as not to reverse. Further, during downshifting, a negative inertia torque is generated as the gear ratio (input shaft rotational speed / output shaft rotational speed) increases. As a result of subtracting the negative inertia torque from the input shaft torque, a positive When it is determined that the output shaft torque is negatively reversed with respect to the input shaft torque, a torque up request signal is output to the engine, and the output shaft torque is not reversed negatively even if a negative inertia torque occurs. As described above, the input shaft torque is further increased.
[0014]
According to a third aspect of the present invention, the request for the torque change amount is changed according to the inertia torque.
According to such a configuration, the request for the torque change amount for preventing the positive / negative reversal of the output shaft torque due to the occurrence of the inertia torque differs depending on the inertia torque, so that the torque change request for the engine is changed according to the inertia torque.
[0015]
According to a fourth aspect of the invention, the inertia torque is estimated according to the target shift time.
According to such a configuration, the inertia torque generated with the shift is estimated according to the target shift time in the shift at that time, and the inertia torque whose absolute value increases as the target shift time is shorter is estimated.
[0016]
According to the fifth aspect of the present invention, the output shaft torque of the engine is estimated based on the intake air amount and the rotational speed of the engine, and the torque ratio of the torque converter interposed between the engine and the speed change mechanism is compared with the engine. The input shaft torque of the transmission mechanism is estimated based on the output shaft torque.
[0017]
According to this configuration, the engine output shaft torque is estimated from the air amount and the rotational speed, assuming that the engine is driven from the drive wheel side, and the estimated engine output shaft torque is calculated by the torque converter torque ratio. , Converted into the input shaft torque of the transmission mechanism.
[0018]
The torque ratio of the torque converter is obtained from the speed ratio, and the speed ratio is obtained from the pump rotational speed (engine rotational speed) and the turbine rotational speed.
[0019]
【The invention's effect】
According to the first aspect of the present invention, the output shaft torque of the speed change mechanism can be prevented from reversing positive and negative due to inertia torque generated with the speed change, thereby giving the driver a feeling of deceleration during acceleration, There is an effect that it is possible to avoid giving a feeling of acceleration during deceleration.
[0021]
According to the second aspect of the present invention, it is possible to prevent the driver from feeling acceleration due to generation of a positive inertia torque during deceleration, and to give the driver a feeling of deceleration due to generation of negative inertia torque during acceleration. There is an effect that it can be prevented.
[0022]
According to the third aspect of the present invention, there is an effect that the influence of the inertia torque can be surely avoided by the request for changing the engine torque.
According to the fourth aspect of the present invention, there is an effect that the inertia torque generated with the shift can be easily obtained.
[0023]
According to the fifth aspect of the invention, there is an effect that the input shaft torque of the speed change mechanism can be estimated with high accuracy.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 shows an engine 1 mounted on a vehicle and an automatic transmission 2 combined with the engine 1.
[0025]
The automatic transmission 2 is configured such that a gear-type transmission mechanism 2a is connected to the engine 1 via a torque converter 2b, and controls hydraulic pressure supplied to various friction engagement elements by solenoid valves 3A to 3E. The solenoid valves 3 </ b> A to 3 </ b> E are controlled by a control signal from the A / T control unit 10.
[0026]
The A / T control unit 10 receives detection signals from an accelerator sensor 11 for detecting an accelerator pedal opening (accelerator opening) AP operated by a driver and a vehicle speed sensor 12 for detecting a vehicle speed VSP. The Then, the shift stage is determined with reference to a shift map in which the shift stage is set in advance according to the accelerator opening AP and the vehicle speed VSP, and the operation state (engagement) of each friction engagement element set in advance for each shift stage. The solenoid valves 3A to 3E are controlled in response to the release, and the gears are automatically shifted to gear positions corresponding to the accelerator opening AP and the vehicle speed VSP.
[0027]
Further, the A / T control unit 10 detects a turbine sensor 13 for detecting the turbine rotational speed Nt of the torque converter 2a, an air flow meter 14 for detecting the intake air amount Qa of the engine 1, and a crank angle of the engine 1. A detection signal from the crank angle sensor 15 is input.
[0028]
The rotational speed Ne of the engine 1 is calculated based on the detection signal from the crank angle sensor 15.
The engine 1 is a four-cycle gasoline engine, the amount of intake air is adjusted by a throttle valve 4 that opens and closes in conjunction with an accelerator pedal, and the fuel injected from a fuel injection valve (not shown) and the intake through the throttle valve 4 Combustion mixture is formed by the air to be ignited, and the combustion mixture is ignited and burned by spark ignition by a spark plug (not shown).
[0029]
The engine control unit 21 receives detection signals from the air flow meter 14, the crank angle sensor 15, etc., and controls the fuel injection amount by the fuel injection valve based on these signals, and controls the ignition timing of the spark plug. Control.
[0030]
Here, the A / T control unit 10 is configured to output a torque change request signal to the engine control unit 21 as necessary at the time of shifting. The output control of the torque change request signal according to will be described.
[0031]
In the flowchart of FIG. 2, first, in step S1, the vehicle speed VSP, the accelerator opening AP, the intake air amount Qa, the engine rotational speed Ne, the turbine rotational speed Nt, and the like are read.
[0032]
In step S2, the shift speed required corresponding to the current vehicle speed VSP and the accelerator pedal opening AP is obtained by referring to the shift map.
In step S3, it is determined whether or not a shift is necessary by comparing the current shift speed with the required shift speed determined in step S2.
[0033]
Here, when it is determined that the current shift speed is the same as the required shift speed obtained in step S2 and that no shift is necessary, this routine is terminated.
On the other hand, if the current shift speed is different from the required shift speed determined in step S2, and the upshift or the downshift is necessary, the process proceeds to step S4.
[0034]
In step S4, the input shaft torque Tt of the speed change mechanism 2a is estimated.
As shown in FIG. 3, the A / T control unit 10 is set in advance with a map that stores the engine output shaft torque Te corresponding to the intake air amount Qa and the engine rotational speed Ne. Then, the engine output shaft torque Te at that time is obtained. The map storing the engine output shaft torque Te represents the output shaft torque Te in a state where the engine 1 is driven reversely from the drive wheel side by deceleration as negative.
[0035]
When the engine output shaft torque Te is obtained, the torque ratio of the torque converter 2a is obtained from the speed ratio of the torque converter 2a obtained from the engine rotation speed Ne and the turbine rotation speed Nt, and the torque ratio and the engine output shaft torque Te are calculated. Then, the input shaft torque Tt of the speed change mechanism 2b is obtained.
[0036]
In step S5, as shown in FIG. 4, a table in which the absolute value of inertia torque Tinr is stored in advance according to the target shift time is obtained, and the absolute value of inertia torque Tinr generated in association with the shift is obtained.
[0037]
In step S6, it is determined whether or not the current shift is an upshift, and if it is an upshift, the process proceeds to step S7.
In step S7, it is determined whether or not the input shaft torque Tt of the speed change mechanism 2b is negative and the result obtained by adding the inertia torque Tinr to the input shaft torque Tt is positive.
[0038]
At the time of upshifting, a positive inertia torque Tinr is generated along with the shift (rotation reduction), and the transmission torque (output shaft torque of the transmission mechanism 2b) in the transmission mechanism 2b becomes the input shaft torque Tt + the inertia torque Tinr. Here, when the input shaft torque Tt is negative but the input shaft torque Tt + the inertia torque Tinr is positive, as shown in FIG. 5, the transmission mechanism 2b is driven by the inertia torque Tinr generated in association with the shift. Output shaft torque reverses from negative (deceleration) to positive (acceleration). For example, in an upshift accompanying an accelerator closing operation, there is a possibility of giving the driver a feeling of jumping out (acceleration feeling).
[0039]
Therefore, when the input shaft torque Tt of the speed change mechanism 2b is negative and the result of adding the inertia torque Tinr to the input shaft torque Tt is positive, the process proceeds to step S8, and the engine output shaft torque is changed during the shift. A torque change request signal (torque down request signal) for forcibly decreasing Te is output to the engine control unit 21 side.
[0040]
That is, by forcibly reducing the engine output shaft torque Te during the shift, even if the inertia torque Tinr is added, the output shaft torque of the transmission mechanism 2b does not reverse from negative (deceleration) to positive (acceleration). To do.
[0041]
The torque change amount (torque down amount) for reducing the engine output shaft torque Te may be a fixed value, but preferably, the engine control unit 21 side is requested to use the inertia torque Tinr + margin as the torque down change amount. Is preferred.
[0042]
Upon receiving the torque down request signal, the engine control unit 21 side corrects the ignition timing and corrects the reduction of the engine intake air amount to reduce the engine output shaft torque Te. This is controlled by the retard correction amount and the reduction correction amount of the intake air amount.
[0043]
On the other hand, if the input shaft torque Tt of the speed change mechanism 2b is positive, or if the input shaft torque Tt is negative but negative even if the inertia torque Tinr is added, a torque change request signal is output. Instead, this routine is terminated.
[0044]
However, during an upshift where the input shaft torque Tt of the speed change mechanism 2b is negative, the torque reduction request signal is sent to the engine regardless of whether the result of adding the inertia torque Tinr to the input shaft torque Tt is positive or negative. It is good also as a structure output to the control unit 21 side. This is because, at the time of up-shifting in which the input shaft torque Tt of the speed change mechanism 2b is negative, deceleration is weakened by the inertia torque Tinr even if the result of adding the inertia torque Tinr to the input shaft torque Tt is negative. It is.
[0045]
Further, when it is determined in step S6 that the upshift is not performed, that is, when the downshift is performed, the process proceeds to step S9.
In step S9, it is determined whether or not the input shaft torque Tt of the speed change mechanism 2b is positive and the result obtained by subtracting the inertia torque Tinr from the input shaft torque Tt is negative.
[0046]
During the downshift, a negative inertia torque Tinr is generated along with the shift (rotation increase), and the transmission torque in the transmission mechanism 2b (the output shaft torque of the transmission mechanism 2b) becomes the input shaft torque Tt−the inertia torque Tinr. Here, when the input shaft torque Tt is positive but the input shaft torque Tt−the inertia torque Tinr is negative, as shown in FIG. 6, the transmission mechanism is generated by the inertia torque Tinr generated along with the shift. 2b indicates that the output shaft torque reverses from positive (acceleration) to negative (deceleration). For example, in a downshift accompanying an accelerator operation, there is a possibility of giving the driver a feeling of deceleration (feeling of poor acceleration).
[0047]
Therefore, when the input shaft torque Tt of the speed change mechanism 2b is positive and the result obtained by subtracting the inertia torque Tinr from the input shaft torque Tt is negative, the process proceeds to step S10, and the engine output shaft torque is changed during the shift. A torque change request signal (torque up request signal) for forcibly increasing Te is output to the engine control unit 21 side.
[0048]
That is, by forcibly increasing the engine output shaft torque Te during shifting, the output shaft torque of the transmission mechanism 2b does not reverse from positive (acceleration) to negative (deceleration) even when the inertia torque Tinr is subtracted. To do.
[0049]
In this case as well, the torque change amount (torque up amount) that increases the engine output shaft torque Te may be a fixed value. However, preferably, the inertia torque Tinr + margin is set as the torque up change amount and the engine control unit 21 side is set. It is preferable to request.
[0050]
The engine control unit 21 that has received the torque-up request signal performs an advance correction of the ignition timing, an increase correction of the engine intake air amount, and the like to increase the engine output shaft torque Te. This is controlled by the advance angle correction amount and the intake air amount increase correction amount.
[0051]
On the other hand, if the input shaft torque Tt of the speed change mechanism 2b is negative, or if the input shaft torque Tt is positive but positive even if the inertia torque Tinr is subtracted, a torque change request signal is output. Instead, this routine is terminated.
[0052]
However, during a downshift where the input shaft torque Tt of the speed change mechanism 2b is positive, the torque increase request signal is sent to the engine regardless of whether the result of subtracting the inertia torque Tinr from the input shaft torque Tt is positive or negative. It is good also as a structure output to the control unit 21 side. This is because, when downshifting in which the input shaft torque Tt of the speed change mechanism 2b is positive, even if the result of subtracting the inertia torque Tinr from the input shaft torque Tt is positive, acceleration is weakened by the inertia torque Tinr. It is.
[0053]
In the above embodiment, the A / T control unit 10 and the engine control unit 21 are individually provided. However, the engine and the automatic transmission may be controlled by one control unit.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an embodiment.
FIG. 2 is a flowchart showing torque-up / torque-down control during shifting according to the embodiment.
FIG. 3 is a diagram showing a map for obtaining engine output shaft torque.
FIG. 4 is a diagram showing a table for obtaining inertia torque.
FIG. 5 is a time chart showing a torque down request state in an upshift.
FIG. 6 is a time chart showing a torque-up request state in a down shift.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Automatic transmission 2a ... Transmission mechanism 2b ... Torque converter 10 ... A / T control unit 11 ... Accelerator sensor 12 ... Vehicle speed sensor 13 ... Turbine sensor 14 ... Air flow meter 15 ... Crank angle sensor 21 ... Engine control unit

Claims (5)

By estimating the input shaft torque of the speed change mechanism and the inertia torque generated with the speed change , comparing the positive / negative of the input shaft torque with the positive / negative of the result of adding the inertia torque to the input shaft torque. Accordingly, it is determined whether or not the sign of the output shaft torque of the speed change mechanism is reversed, and when the sign of the output shaft torque is reversed , a torque change request signal during shifting is output to the engine. A shift control device for an automatic transmission, characterized in that When it is determined that the sign of the output shaft torque is reversed during upshifting , a torque down request signal is output to the engine,
2. The shift control apparatus for an automatic transmission according to claim 1, wherein a torque up request signal is output to the engine when it is determined that the sign of the output shaft torque is reversed during downshifting. The shift control device for an automatic transmission according to claim 1 or 2, wherein a request for a torque change amount is changed according to the inertia torque. The shift control apparatus for an automatic transmission according to any one of claims 1 to 3 , wherein the inertia torque is estimated according to a target shift time. The engine output shaft torque is estimated based on the intake air amount and the rotational speed of the engine, and based on the torque ratio of a torque converter interposed between the engine and the transmission mechanism and the engine output shaft torque. The shift control device for an automatic transmission according to any one of claims 1 to 4 , wherein an input shaft torque of the transmission mechanism is estimated.

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