JP2001214771A - Throttle control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the shifting shock in the shift-up of an automatic transmission. SOLUTION: A throttle valve 14 having an actuator 20 is provided on the intake passage 12 of an engine 1, and the throttle valve opening is controlled by an electronic control unit(ECU) 30. The ECU detects the actual start timing and end timing of a torque phase in the shift-up on the basis of the change gear ratio of engine output torque to automatic transmission output shaft torque in the shift-up operation of the automatic transmission 40, and retains the start timing as learning value. When the shift-up operation is started, the ECU 30 predicts the start timing of the torque phase on the basis of the learning value and controls the actuator of the throttle valve so that the output torque of the engine starts to increase in conformation to the predicted start timing. According to this, the engine output torque increasing operation precisely conformed to the period of the torque phase is performed, and the shifting shock at the torque phase is surely suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle control device for an internal combustion engine, and more particularly, to a temporary decrease in output torque of an automatic transmission caused by a torque phase during a shift up operation of an internal combustion engine having an automatic transmission. The present invention relates to a throttle control device for an internal combustion engine that suppresses the occurrence of a throttle.

[0002]

2. Description of the Related Art In a vehicle equipped with an internal combustion engine equipped with an automatic transmission, when the automatic transmission is upshifted, that is, when a shift operation is performed to increase the transmission ratio from a low gear to a high gear of the transmission.
It is known that a so-called torque phase occurs in which the output torque (drive torque of the vehicle) of the automatic transmission temporarily decreases. Due to this torque phase, in a vehicle equipped with an internal combustion engine with an automatic transmission, torque shock occurs even during upshifting, and there is a problem that the driving sensation of the vehicle deteriorates. In order to solve this problem, various control devices have been proposed which increase the engine output torque at the time of an upshift operation of the automatic transmission and prevent the drive torque from decreasing.

An example of this type of control device is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-218911.
The control device disclosed in the above publication increases the throttle valve opening by an amount according to the state of the shift operation at the start of the upshifting operation of the automatic transmission, thereby reducing the drive torque by the torque phase by an amount necessary to compensate for the decrease. This is to increase the engine output torque.

[0004]

However, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 8-218911, although the engine output torque is increased as much as necessary to prevent a decrease in driving torque when a torque phase is generated, No detailed study has been made on when to start or when to increase the engine output torque. For this reason, in the device disclosed in the above publication, the period in which the drive torque is reduced due to the actual torque phase and the period in which the engine output torque is increased may not exactly match, and the torque shock at the time of the shift up operation of the automatic transmission may be effective. There is a problem that cannot be suppressed.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a throttle control device for an internal combustion engine capable of increasing the output of the engine exactly in accordance with the torque phase generation period at the time of upshifting. It is an object.

[0006]

According to the first aspect of the present invention, there is provided a throttle control device for an internal combustion engine having an automatic transmission, wherein a throttle valve opening degree is independent of a driver's operation of an accelerator pedal. Throttle valve driving means, a torque phase detecting means for detecting the occurrence of a torque phase in which the automatic transmission output torque temporarily decreases after the start of an upshift operation of the automatic transmission, and a torque phase detecting means for detecting the detected torque phase. Control means for controlling a throttle valve opening change operation by the throttle valve driving means such that the engine output torque increases in accordance with a period in which a torque phase is generated, based on the start time and the end time. And a throttle control device for an internal combustion engine.

That is, according to the first aspect of the present invention, the start and end times of the actual torque phase at the time of upshifting are detected by the torque phase detecting means, and based on the detected torque phase start and end times. Thus, while the torque phase is occurring, the throttle valve opening is controlled so that the engine output torque increases. As a result, the period during which the engine output torque is increased and the period during which the torque phase is generated accurately match, and torque shock during upshifting is suppressed.

According to the second aspect of the present invention, the control means learns the actual start time of the torque phase detected by the torque phase detection means, and predicts the torque phase start time based on the learning result. 2. The throttle according to claim 1, further comprising: controlling a throttle valve opening change operation by the throttle valve driving means so that the engine output torque starts increasing in accordance with the predicted torque phase start timing. 3. A control device is provided.

In other words, in the invention of claim 2, the control means predicts the torque phase start time at the time of the shift-up operation based on the learning result, and increases the engine output torque in accordance with the predicted start time. Controls the throttle valve opening. The operation of increasing the output torque by changing the throttle valve opening involves a delay time such as the time required for operating the throttle valve driving means or the time required for the engine output torque to change after the throttle valve opening is changed. Therefore, some time is required until the engine output torque actually increases after the start of the throttle valve opening change operation. For this reason,
If the operation for increasing the output torque by changing the opening of the throttle valve is actually started after the start of the torque phase, the decrease in the driving torque at the start of the torque phase cannot be effectively suppressed.
In the present invention, the start timing of the torque phase at the time of the upshifting operation is predicted, and the throttle valve opening change operation is performed so that the engine output torque starts increasing at the predicted start timing of the torque phase. As a result, the torque phase start timing and the engine output torque increase timing accurately match. In addition, the start timing of the torque phase at the time of the shift-up operation does not become a fixed value due to variations among products, aging, and the like, even for vehicles of the same type. According to the present invention, the actual torque phase start timing detected by the detecting means during operation is learned, and the torque phase start timing is predicted based on the learned value, so that variations and aging due to products occur. However, it is possible to accurately prevent the occurrence of a shift shock due to the torque phase.

According to the third aspect of the present invention, the torque phase detecting means determines the actual start time and end time of the torque phase based on the engine output torque change rate and the automatic transmission output torque change rate. A throttle control device for an internal combustion engine according to claim 1 or 2 for detecting the throttle control. That is, in the invention of claim 3, the torque phase detecting means detects the actual start and end times of the torque phase from the engine output torque change rate and the automatic transmission output torque change rate. Thus, the start time and the end time of the torque phase can be accurately detected. The rate of change between the engine output torque and the automatic transmission output torque may be directly detected by attaching a torque sensor to each output shaft, or a physical quantity equivalent to each torque change rate may be detected. May be detected (estimated) indirectly based on the torque change rate.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall view of an internal combustion engine with an automatic transmission to which the present invention is applied. In FIG. 1, reference numeral 1 denotes an internal combustion engine. In this embodiment, a gasoline engine is used as the internal combustion engine 1. In FIG. 1, reference numeral 3 denotes an engine 1
, 6 indicates an intake port of the engine, and 8 indicates an exhaust port. Each intake port 6 is connected to a surge tank 10 via an intake branch pipe 9, and each branch pipe 9 is provided with a fuel injection valve 11 for injecting fuel into each intake port 6.

The surge tank 10 is connected to an air cleaner 13 through an intake passage 12, and a throttle valve 14 is disposed in the intake passage 12. The throttle valve 14 of the present embodiment is provided with an electronic control unit (EC
U) An electronically controlled throttle valve having an appropriate type of actuator 20 such as a stepper motor which operates in response to a command from the ECU 30 and taking an opening in accordance with a command signal from the ECU 30. The ECU 30 controls the opening of the throttle valve 14 to an opening corresponding to the operation amount of the accelerator pedal (not shown) of the driver during normal driving, and applies a shift shock during an upshift operation of the automatic transmission 40 described later. To prevent this, the opening of the throttle valve 14 is controlled independently of the operation of the accelerator pedal by the driver.

The exhaust port 8 of the engine 1 is connected to the exhaust manifold 1
6 is connected to the exhaust passage 17. FIG.
Reference numeral 40 denotes an automatic transmission connected to an output shaft (not shown) of the engine 1. The automatic transmission 40 includes a torque converter 41 and a transmission 42, and an output shaft of the transmission 42 is connected to driving wheels of the vehicle via a differential gear (not shown).

The transmission 42 is of a known type including a planetary gear train and a friction element, and switches the control oil pressure to switch the engagement state of the friction element (brake, clutch, etc.) to change each of the planetary gear trains. The gear shifting operation is performed by fixing and connecting the elements. The torque converter 41 is of a known type including a pump directly connected to an engine output shaft and a turbine driven by the pump discharge fluid. Directly connected to the input shaft. The torque converter 41 performs a known torque amplifying operation of amplifying torque input from the engine output shaft and outputting the amplified torque to the converter output shaft. The automatic transmission 40 also includes a transmission output shaft rotation speed sensor 23 that outputs a pulse signal having a frequency corresponding to the rotation speed of the output shaft of the transmission 42, and a signal corresponding to the temperature of the automatic transmission control oil. An output oil temperature sensor 22 is provided.

In FIG. 1, reference numeral 30 denotes an electronic control unit (ECU) of the engine 1. The ECU 30 includes a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, a CPU (Microprocessor) 34, an input port 35, and an output port 36.
In addition to performing basic control such as fuel injection amount control and ignition timing control of the engine 1 in this embodiment, the digital computer according to the present embodiment controls the running state of the vehicle (throttle valve opening and running speed). The shift operation of the automatic transmission 40 is accordingly controlled, and the opening control of the throttle valve 14 is performed to prevent a shift shock when the transmission 40 is upshifted.

For the above purpose, the input port 35 of the control circuit 30 is supplied with a voltage signal indicating the vehicle running speed from the vehicle speed sensor 24 and a voltage signal indicating the automatic transmission control oil temperature from the oil temperature sensor 22. In addition to being input via a converter 37, a pulse signal representing the engine speed from a speed sensor 21 provided on a crankshaft (not shown) of the engine and a signal from a transmission output shaft speed sensor 23 are provided. Pulse signals are input.

The output port 36 of the control circuit 30
The control valve is connected to a control valve for controlling a shift operation of the automatic transmission 40 via a drive circuit 38, and controls the shift operation. In addition, the fuel injection valve 11, the spark plug, and the throttle are respectively connected via corresponding drive circuits 38. It is connected to a valve actuator 20 and controls the fuel injection from the fuel injection valve 11, the ignition timing of the engine, and the opening of the throttle valve 14.

Next, the upshift operation of the automatic transmission will be described with reference to FIGS. 2 (A) to 2 (C). FIG.
FIG. 2A is a timing chart showing variations of a transmission output shaft torque (drive torque), a converter output shaft rotation speed, and a shift control oil pressure during a shift-up operation of an automatic transmission. FIG. 5 shows a change in transmission output shaft torque (drive torque) during operation. FIG. 2B shows a change in the rotation speed of the converter output shaft (transmission input shaft rotation speed) during a shift-up operation, and FIG. 2C shows a change in the automatic transmission control oil pressure.

2 (A) to 2 (C), for example, if the relationship between the throttle valve opening and the vehicle running speed at the time of running satisfies the condition for upshifting, the ECU 30 will be described.
Outputs an upshift command signal at a point in time after a predetermined time has elapsed from the point in time. When a shift command signal is output at that time, the control valve of the control hydraulic circuit of the automatic transmission is switched, and the switching hydraulic pressure for controlling the shift clutch starts increasing as shown in FIG. 2 (C). The switching hydraulic pressure hardly increases during the period corresponding to the amount of bending of the return spring of the control valve after the transmission of the shift command (the period from FIG. 2 (A) to (C)). The ascent starts when the switching of the valve is completed (FIG. 2 (C)). Therefore, the shift operation of the automatic transmission is actually started in FIG.
(A) to (C). In addition, since the control hydraulic circuit is provided with an accumulator for preventing a sudden change in hydraulic pressure, if the hydraulic pressure rises to some extent after switching, the accumulator piston starts moving by compressing the spring (FIG. 2C). )) The rising speed of the hydraulic pressure decreases, and the switching hydraulic pressure of the transmission clutch gradually increases. When the accumulator piston fully compresses the spring and moves to the limit, the accumulator operation stops and the oil pressure rises rapidly (FIG. 2 (C)).

Next, a change in the transmission output shaft torque (drive torque) when the switching hydraulic pressure changes as described above will be described with reference to FIG. Before the switching hydraulic pressure starts to increase (before the time point), the driving torque is set to a value corresponding to the speed ratio of the low speed side of the transmission (exactly, engine output torque × converter torque amplification ratio × low speed side speed ratio). Has become. Next, when the switching hydraulic pressure starts to increase at the time, the driving torque temporarily decreases, increases again from the time, and increases in response to the change in the pressing force of the transmission clutch due to the increase in the switching hydraulic pressure (from). Then, when the switching hydraulic pressure reaches a certain value, the pressure suddenly decreases (), and thereafter, the drive torque (engine output torque × converter torque amplification ratio × high speed gear ratio) according to the gear ratio of the high gear.

That is, during an upshift operation of the automatic transmission from the low gear to the high gear, a period (from) when the driving torque temporarily decreases after the operation is started, and the driving torque temporarily increases thereafter. Periods (from) occur, and only after the lapse of these periods, a driving torque corresponding to the gear ratio of the high-speed stage after switching can be continuously obtained.

Here, during the period from the time point, when shifting to the high speed stage by gradually engaging the high speed stage clutch in the automatic transmission, the low speed stage clutch which has been engaged until now is engaged. Is a period until the engagement is released. In this period, the engine speed does not change because the clutch on the low speed side is engaged. Also, the period from the time point is a transitional period from the end of switching from the low speed side clutch to the high speed side clutch until the engine speed decreases, and after the time point, the decrease of the engine speed ends, This shows a period after the number of rotations has reached the speed corresponding to the gear ratio on the high speed side.

The period from the above, that is, the period in which the driving torque temporarily decreases, is a period from the start of engagement of the high-speed-stage-side clutch until a change in the engine speed appears. This period (phenomenon) is generally referred to as a torque phase because only the drive torque changes without performing this operation. During the period from the above, that is, during the period when the driving torque temporarily increases, after the completion of the switching to the high speed stage, the engine speed is increased from the high rotation speed before the switching to the reduction ratio of the high speed stage due to the inertia of the vehicle. This is a period until the number of revolutions decreases in accordance with the above. For this reason, this period (phenomenon) is generally called an inertia phase.

The cause of the decrease in the driving torque in the torque phase (period from the time point) is complicated, but simply, one of the clutches in the automatic transmission is gradually engaged while the other clutch is simultaneously engaged. When switching to the high speed stage by releasing the engagement, the torques transmitted by the two clutches cancel each other out and the transmission torque is consumed by the slipping of the clutches, so that the transmission output torque (drive torque) is reduced. It is considered that a phenomenon of reduction occurs. At the end of the torque phase (time point), the drive torque temporarily drops to the torque after the switching to the gear ratio on the high speed side (the drive torque after the end of the inertia phase).

Further, the reason why the drive torque once increases in the inertia phase (period from the time point) and then decreases to a value corresponding to the speed ratio on the high speed side is as follows. That is, when the power transmission path is switched from the low speed side to the high speed side at the time, the transmission input shaft is connected to the vehicle drive system via the high speed side power transmission path, and Attempts to rotate at a lower rotational speed than when connected to the vehicle driveline via the power transmission path. However, at this time, since the engine itself is operating at a high rotational speed when traveling on the low speed side, the rotation of the transmission input shaft (that is, the rotation of the converter output shaft) does not immediately decrease. On the other hand, since the transmission output shaft is connected to the vehicle drive system, the transmission output shaft attempts to continue rotating at a constant speed corresponding to the vehicle speed. Therefore, immediately after switching to the high-speed stage, the input shaft rotation speed of the transmission is higher than the value corresponding to the transmission output shaft rotation speed, and the rotation speed difference between the transmission input shaft and the output shaft is high. It is absorbed by the slip of the speed-change clutch. That is, at the end of the torque phase (time point), the drive torque is reduced to a torque (drive torque after the end of the inertia phase) corresponding to the gear ratio after the high-speed gear shift due to slippage of the high-speed gear shift clutch. On the other hand, the slip of the clutch causes a brake torque to decrease the input shaft rotation speed, that is, the engine rotation speed, from the vehicle drive system to the transmission input shaft side. As a result, the transmission output torque (drive torque) increases. Further, since the above-mentioned brake torque is generated by slippage of the switching clutch, the magnitude thereof increases as the switching hydraulic pressure (clutch pressing force) increases. Therefore, in the period from the time of FIG. 2A, the brake torque increases with the increase of the switching hydraulic pressure (FIG. 2C), and the reaction torque causes the phenomenon that the driving torque increases. This inertia phase is determined by the above-mentioned brake torque.
As shown in (B), when the engine speed (converter output shaft speed) decreases and the rotations of the transmission output shaft and input shaft are synchronized (time point), the process ends.

As described above, during an upshift operation of the automatic transmission, a decrease in drive torque due to the torque phase and an increase in drive torque due to the inertia phase occur continuously.
There is a problem that torque shock occurs during gear shifting and the driving sensation of the vehicle deteriorates. As described above, conventionally, an attempt has been made to increase the engine output torque during a shift-up operation to compensate for a decrease in drive torque due to a torque phase. However, for this purpose, it is necessary to accurately match the start and end of the increase in the engine output torque with the start and end times of the torque phase. However, it is actually difficult to accurately determine the start and end times of the torque phase, and the start and end times of the torque phase are likely to be varied due to individual differences between products and aging and are not constant. Therefore, in the conventional method, the timing of the torque phase and the timing of the increase of the engine output do not exactly match, and conversely, there is a case where the torque shock at the time of shifting is amplified.

In this embodiment, the start and end timings of the torque phase are actually detected by the method described below, and the engine output torque increasing operation is performed based on the detected start and end timings of the torque phase. It is possible to prevent torque shock when shifting up the transmission. First, the actual torque phase detection operation in the present embodiment will be described.

In the torque phase, the driving torque is reduced.
For example, it is also possible to provide a torque sensor for detecting the shaft torque on the output shaft (drive shaft) of the automatic transmission to monitor the shaft torque, and set the point at which the shaft torque starts to decrease at the time of upshifting as the torque phase start point. . However, actually, it is not preferable to install a torque sensor because the cost of the apparatus is increased. Therefore, in this embodiment, the rate of change between the engine output torque and the drive torque is indirectly detected, and the start and end of the torque phase are determined based on the detected rate of change.

FIG. 3 is a diagram schematically showing changes in the engine output torque Te and the drive shaft torque To before and after the start of the torque phase. In FIG. 3, the vertical axis represents torque, and the horizontal axis represents time. In the state where the clutch does not slip before the shift of the automatic transmission starts (that is, before the start of the torque phase), the engine output torque Te and the drive shaft torque To are balanced, and the relationship between the two is expressed by the following equation. .

Te × A × B = To where A is the amplification ratio of the torque converter, and B is the speed ratio before shifting (low speed stage). Therefore, before the start of the torque phase, the slope (change rate with respect to time) between the curve Te × A × B and the curve To matches. That is, (Te) ₍₁₎ × A × B− (To) ₍₁₎ = 0 where (Te) ₍₁₎ and (To) ₍₁₎ are the first order differential values of Te and To with respect to time, respectively. Represents.

However, as described above, the torque phase is caused by the consumption of the driving torque due to the slippage of the transmission clutch. Therefore, when the torque phase starts, only the driving torque decreases although the engine output torque does not decrease. I will be. Therefore, when the torque phase starts, FIG.
As schematically shown in FIG. 5, the slope of To is represented by a curve Te × A × B.
Is always smaller than the inclination of.

Therefore, (Te) ₍₁₎ × A × B− (T
o) ₍₁₎ It can be determined that the time when> 0 is the start time of the torque phase. Also, at the end of the torque phase, contrary to the start, only the drive torque increases although the engine output torque does not increase. For this reason,
(Te) ₍₁₎ × A × B− (To) ₍₁₎ It can be determined that the time when <0 is the end time of the torque phase.

That is, if (Te) ₍₁₎ × A × B− (To) ₍₁₎ = C (1), the change rate (Te) ₍₁₎ of the engine output torque at the time of upshifting is expressed by By detecting the drive shaft torque change rate (To) ₍₁₎ and monitoring the value of C calculated by the equation (1), when the value of C changes from C = 0 to C> 0 Is the start time of the torque phase (FIG. 2, time point), from C> 0 to C <
The time when it changes to 0 is the end time of the torque phase (Fig. 2, time point)
Can be determined.

Although it is possible to directly detect the engine output torque and the drive shaft torque by installing a torque sensor respectively, it is not practical to use the torque sensor as described above. Further, the engine output torque can be easily calculated based on the operating state of the engine (for example, the opening degree of the throttle valve 14 and the engine speed). Therefore, in the present embodiment, a physical amount equivalent to the drive shaft torque change rate is not directly detected but detected indirectly from the physical amount.

Now, assuming that the value obtained by converting the running resistance of the vehicle into the drive shaft torque (running resistance torque) is Tr and the drive shaft rotational speed is W, the rate of change (W) of the rotational speed W ₍₁₎ is It is represented by K2 × (W) ₍₁₎ = To−Tr (2) That is, if the running resistance torque Tr is larger than the drive shaft torque To, the drive shaft rotation speed W decreases (that is, the vehicle decelerates), and conversely, the drive shaft torque W decreases. If Tr is small, W increases (that is, the vehicle accelerates).

Here, when both sides of the equation (2) are differentiated with respect to time, K2 × (W) ₍₂₎ = (To) ₍₁₎ − (Tr) ₍₁₎ ((W) ₍₂₎ is the second-order time derivative of W, (Tr)
₍₁₎ is the first-order time derivative of Tr. Now, in a short time before and after the upshift operation, the running resistance T
Since r is considered to be substantially constant, (Tr) ₍₁₎ = 0 can be set. Therefore, the above equation is as follows: K2 × (W) ₍₂₎ = (To) ₍₁₎ (3)

By transforming the above-mentioned equation (1) for determining the torque phase using equation (3), the following equation is obtained: (Te) ₍₁₎ × A × B−K2 ×
(W) ₍₂₎ = C, and (Te) ₍₁₎ −K3 × (W) ₍₂₎ = D (4) is obtained.

That is, the value D calculated from the second-order time differential value of the drive shaft rotational speed W and the first-order time differential value of the engine output torque in the above equation (4) instead of C in the above equation (1). The start and end timings of the torque phase can be detected by judging the sign of the torque phase. In the present embodiment, the value of the engine output torque Te is determined in advance by the ECU 30 in the form of a two-dimensional numerical map using the throttle valve opening TH and the engine speed NE.
It is stored in the OM32. The ECU 30 calculates the throttle valve opening TH based on, for example, the number of steps of the stepper motor of the actuator 20 of the throttle valve 14 at regular intervals, and calculates the engine speed NE based on the output pulse of the speed sensor 21. At the same time, the engine output torque Te is calculated from the values of TH and NE based on the numerical map. Output torque Te change rate (Te)
₍₁₎ can be obtained as (Te) ₍₁₎ = ΔTe / Δt by calculating the amount of change ΔTe of Te during the time Δt.

The ECU 30 calculates the rotation speed W of the output shaft (drive shaft) of the automatic transmission based on the output of the rotation speed sensor 23, and calculates the amount of change ΔW of W during the time Δt. Then, using ΔW, (W) ₍₁₎ is converted to (W) ₍₁₎
= ΔW / Δt, and the value of the variation Δ (W) ₍₁₎ to (W) ₍₂₎ of (W) ₍₁₎ during the fixed time Δt is calculated as (W) ₍₂₎ = Δ (W) ₍₁₎ / Δt.

The ECU 30 further performs automatic shift upshifting.
Determined above during operation (Te) ₍₁₎And (W)₍₂₎When
Calculate the judgment value D from the equation (4) based on
Then, the start and end of the torque phase are determined. Note that the aforementioned
In the description, the value of D calculated by equation (4) is positive.
Time was the start time of the torque phase, but in actual operation
Due to fluctuations in the drive shaft torque due to the torque converter,
Before the start of the phase, D> 0 may be satisfied. For this reason,
In the embodiment, the drive shaft torque fluctuation by the torque converter
Is considered, when D becomes larger than the predetermined value E (E is
Positive value) It is determined that the torque phase has started
You.

Next, a shift shock prevention operation based on detection of the actual start and end timings of the torque phase will be described. FIG. 4 is a timing chart showing a shift shock prevention operation in the torque phase according to the present embodiment. In FIG. 4, (A) shows the shift command timing, (B) shows the change in the drive shaft torque, (C) shows the change in the throttle valve opening degree of the present embodiment, and (D) shows the change in the engine output torque. Is shown.

In this embodiment, the ECU 30 detects the start timing of the torque phase (FIG. 4) by the above-described method every time the upshift operation is performed during operation, and stores it as a learning value. Then, when a shift-up shift command is input during operation, a timing (FIG. 4) at which a torque phase actually occurs after the shift command is input is predicted based on the stored learning value. Further, the ECU 30 determines the delay time of the actuator of the throttle valve 14 (the time from when the throttle valve opening change signal is output until the throttle valve opening is actually changed) and the throttle valve opening based on the current operation state. Then, the sum of the time required for the output torque of the engine to actually increase after the change (the required time for torque change) is calculated.

Further, the ECU 30 starts the prediction control for increasing the throttle valve opening by a predetermined amount in advance of the torque change required time before the torque phase start prediction time (T in FIG. 4).
₁ point). That is, the ECU 30 opens the throttle valve by a predetermined opening before the torque phase start time so that the engine output starts increasing at a time that matches the predicted torque phase start time. It should be noted that the throttle valve opening in this predictive control is set smaller than the opening that only compensates for the amount of torque reduction due to the torque phase.

When the torque phase actually starts within a predetermined time after the start of the predictive control, the ECU 30 performs an opening increasing operation for opening the throttle valve to an amount sufficient to compensate for the amount of torque reduction. performed (Fig. 4, T ₂ points). And EC
When U30 detects the end of the torque phase (FIG. 4), it lowers the throttle valve opening to lower the engine output torque.

As described above, by controlling the throttle valve opening, the actual engine output torque increases exactly in the period of the torque phase as shown in FIG. As a result, in contrast to the conventional driving torque change due to the torque phase as shown by the dotted line in FIG.
In the present embodiment, the drive torque is maintained substantially constant during the torque phase period as shown in FIG. 4B, and shift shock in the torque phase is prevented.

If the torque phase does not start within the above-mentioned predetermined time after the start of the prediction control, the prediction was inaccurate. May fluctuate. For this reason, in the present embodiment, when the torque phase does not start even after the lapse of the predetermined time, the prediction control is stopped, the throttle valve opening is temporarily returned to the state before the start of the prediction control, and the process waits. At the same time that the torque phase is detected, an operation of increasing the throttle valve opening is performed.

FIG. 5 is a flowchart for specifically explaining the shift shock prevention operation in the torque phase. This operation is executed by the ECU 30. FIG. 5, step 501 shows a standby operation for inputting an upshift command.
The operations after step 503 are started only when an upshift command for the automatic transmission is input.

When a shift-up command is input in step 501, the ECU 30 next calculates a learning value TL of a pre-stored torque phase start timing (a time until a torque phase starts after the shift-up command is input). In the present embodiment, the learning value of the torque phase start time is stored in the form of a numerical map using the upshift speed (the speed before and after the upshift) and the control oil pressure of the automatic transmission as parameters. It is updated according to the actual measured value of the time. FIG.
It is not a general relationship between the above parameters and the torque phase start timing. As shown in FIG. 6, the start timing tends to be shorter as the hydraulic pressure is higher or as the shift-up operation is performed at a higher gear.

The control oil pressure of the automatic transmission can be directly detected by providing a pressure sensor. However, the control oil pressure of the automatic transmission is supplied by a hydraulic pump driven by the torque converter input shaft, and the control oil pressure is expressed as a function of the torque converter input shaft rotation speed. Therefore,
The control oil pressure may be calculated from the torque converter input shaft rotation speed. Some automatic transmissions have a hydraulic control valve such as a linear solenoid valve that controls the hydraulic pressure supplied from the hydraulic pump according to operating conditions (engine speed, vehicle speed, throttle valve opening, etc.). However, in this case, the control oil pressure can be obtained as a function of the torque converter input shaft rotation speed and the control valve opening (for example, the duty ratio of the linear solenoid valve drive signal).

When the learning value of the torque phase start timing is obtained in step 503, then in step 505, the prediction control start timing of the throttle valve opening (after the shift-up command is input,
The time until the prediction control is started) TPL is calculated.
As described above, TPL is a throttle valve opening degree change command output time required for the engine output torque to start increasing at the same time as the start of the torque phase. The predictive control start timing TPL is calculated from the value obtained by multiplying the torque phase start timing learning value TL by the automatic transmission control oil temperature correction coefficient LTK from the above-described torque change required time (after the throttle valve opening change command is output, the engine output Time until the torque starts to change) is calculated as a value obtained by subtracting TRQ.

That is, TPL = TL × LTK-TRQ
Becomes FIG. 7 is a diagram showing a change in the oil temperature correction coefficient LTK with respect to the oil temperature. The operating speed of the transmission mechanism of the automatic transmission decreases as the viscosity of the control oil increases, and the time from the input of the upshift command to the start of the torque phase also increases as the control oil viscosity increases. For this reason, as shown in FIG. 7, the value of the correction coefficient LTK becomes a constant value (1.0) in a temperature range where the control oil temperature is sufficiently high (for example, 70 ° C. or more), but the temperature is low in a region below that. Is set to a larger value. In the present embodiment, L
The relationship between TK and oil temperature shown in FIG.
The ECU 30 stores the oil temperature sensor 22 in advance.
The correction coefficient LTK is determined from the relationship shown in FIG.

The required torque change time TRQ is obtained as a function of the engine speed NE and the throttle valve opening TH. The required torque change time TRQ is the operation delay time required for the actuator 20 to change the throttle valve opening after the throttle valve opening change command, and the actual engine output torque after the throttle valve opening changes. It is the total time with the time required. Here, while the operation delay time of the actuator can be regarded as substantially constant, the time from the change of the throttle valve opening to the actual change of the engine output torque is determined by the intake pressure before the change of the throttle valve opening (the throttle valve downstream side). (Intake pipe pressure) and the intake pressure after the opening degree changes. Further, since the intake pressure after the opening degree changes is in a substantially constant range, the time from the change of the throttle valve opening degree to the change of the engine output torque can be approximated as a function of the intake pressure before the change. Further, the intake pressure before the throttle valve opening changes is determined by the throttle valve opening TH.
And the engine speed NE.

Therefore, in the present embodiment, the total of the delay time of the throttle valve operation and the time required for the engine output torque to actually change after the throttle valve opening degree changes (torque change required time), and the engine speed The relationship between NE and the throttle valve opening TH before the change is obtained in advance by an experiment,
It is stored in the ROM 32 of the ECU 30. ECU 30
Is based on the engine speed NE and the throttle valve opening TH before the upshift, and the torque change required time T
Calculate RQ. FIG. 8 is a diagram showing a general relationship among the engine speed NE, the throttle valve opening TH, and the required torque change time TRQ. As shown in FIG. 8, the required torque change time TRQ is such that, when the rotation speed NE is the same, the throttle valve opening TH before the change is larger, and when the throttle valve opening TH is the same, the rotation speed NE is lower. It becomes bigger.

As described above, after calculating the predicted control start time TPL, in steps 507 and 509, the predictive control is started when the time from the input of the shift-up command to the calculated predicted control start time TPL elapses. In the prediction control, a throttle valve opening change command is output to the actuator 20 of the throttle valve 14 so that the opening of the throttle valve 14 becomes the predicted control opening THP. The predicted control opening THP of the throttle valve is equal to a set opening TH for increasing torque, which will be described later.
The opening is set to a value obtained by multiplying I by a predetermined coefficient (for example, 0.25). As a result, if the prediction of the torque phase start timing calculated in steps 503 and 505 is accurate, the engine output torque increases to a value corresponding to the predicted opening degree THP when the torque phase starts, and the torque phase start is started. The timing coincides with the start timing of the engine output increase.

Next, at step 511, the stop time TPS of the predictive control is calculated. As described above, in this operation, the start timing of the torque phase is predicted based on the learning value, and the throttle valve opening degree prediction control is performed so that the engine output starts increasing at this start timing. Therefore, if the actual torque phase does not start even when the predicted start time is reached, the engine output torque increases due to the predictive control even though the drive torque does not decrease due to the torque phase. May cause fluctuations in the driving torque. Therefore, in the present embodiment, if the actual start of the torque phase is not detected even after a predetermined stop time TPS has elapsed since the start of the predictive control, the predictive control of the throttle valve opening is stopped and the throttle valve is stopped. An operation of returning the opening to the opening before the start of the prediction control is performed. The suspension time is set so that the drive torque increase time by the prediction control when the torque phase does not start is within a predetermined time. As described above, the required torque change time TRQ described with reference to FIG. 8 is required from when the throttle valve opening is restored to when the engine output torque returns to the original value. Therefore, in step 511, the time TRQ from the stop of the prediction control to the return of the engine output torque to the original value is calculated again by using FIG. 8, and if the TRQ is short, the prediction control stop time TPS is set to be long. Is longer, the prediction control suspension time is set shorter. In other words, when the TRQ is short, if the actual torque phase start time is later than the predicted start time, the torque control may be continued for a relatively long time until the actual torque phase is started. The engine output torque can be reduced before the influence of the above becomes large. Therefore, the shorter the TRQ is, the longer the prediction control suspension time is set.

Next, in steps 511 to 521, it is determined whether or not the actual torque phase has been detected (step 517) before the elapse of the predictive control start suspension time TPS (step 513). If the torque phase is not detected, the prediction control is stopped at step 515, and the throttle valve opening TH is returned to the opening before the start of the prediction control.

If the torque phase is detected before the stop time TPS elapses (step 517), step 519 is executed, and the detected actual torque phase start timing is used in step 503. Start time learning value T
A learning operation for replacing L is performed. As described above, by learning the torque phase start timing using the actually detected value, even when the actual torque phase start timing changes due to variation due to individual differences or aging, the torque phase start timing can be accurately determined. Can be predicted. As described above, since the torque phase start timing greatly changes depending on the oil temperature of the control oil, the learning operation in step 519 is performed when the oil temperature is sufficiently high (for example, 80 ° C. or higher, see FIG. 7). Perform only in the temperature range that is not affected by the oil temperature.

After execution of the learning operation in step 519, in step 521, the opening of the throttle valve 14 is further increased to THI, and the engine output torque is increased until the drive torque reduction due to the torque phase can be compensated. The throttle valve opening THI after the increase in the throttle valve opening increasing operation in step 521 is set as follows.

That is, the decrease DTo of the drive torque in the torque phase is equal to the difference between the drive torque at the point in FIG. Further, the driving torque To ₃ at the time is
Is expressed as To ₃ = Te ₃ × (speed ratio before shifting) by using the engine output torque Te. Further, the drive To ₄ at the time point is equal to the torque after the end of the inertia phase, that is, the torque after the shift, as described above. For this reason TO
₄ = Te ₄ × (gear ratio after shifting) (Te
₃ and Te ₄ are engine output torques before and after shifting, respectively. Therefore, the drive torque decrease width DT in the torque phase
To compensate for the o, i.e. the engine output torque Te ₄ after the shift required in order to DTo = 0 is, DTo = To ₃ -T
From o ₄ = 0, Te ₃ × (speed ratio before shifting) −Te ₄ ×
(Speed ratio after shifting) = 0, so that Te ₄ = Te ₃ ×
(Speed ratio before speed change) / (speed ratio after speed change). Therefore, the engine output torque Te ₄ after the shift which is required to the driving torque decline DTo to _{0, Te 4 = Te 3 × (} S 3 / S 4) is calculated as (Te ₃ is shifted up The engine output torque before the start of operation, S ₃ and S ₄ are the gear ratios before and after the shift, respectively.

The engine output torque Te is equal to the engine speed N
Since the engine speed NE and the throttle valve opening TH before shifting are determined, the output torque T is maintained while the engine speed NE is kept constant.
e required throttle valve opening THI to increase to ₄
Can be calculated. In the present embodiment, the engine speed NE, the throttle valve opening TH and the engine output torque Te are determined in advance.
And is stored in the ROM 32 of the ECU 30. In step 521, the throttle valve opening THI required for increasing the torque is calculated based on this relationship, and an operation of increasing the throttle valve opening to THI is performed.

FIG. 9 is a diagram showing a general relationship between NE, TH and Te. In the present embodiment, first, an engine output torque Te ₃ before shifting is calculated from the engine speed NE ₃ before shifting and the throttle valve opening TH _3, and then the engine after shifting necessary to prevent a decrease in driving torque. The output torque Te ₄ is calculated as Te ₄ = Te ₃ × (S ₃ / S ₄ ). Throttle valve opening TH required to obtain Te ₄
I is obtained based on NE ₃ and Te ₄ from the relationship shown in FIG.

When the prediction control is stopped in Steps 513 and 515 because the torque phase has not started within the prediction control stop time, when the actual torque phase is detected in Step 517, the torque in Step 519 is determined. Learning operation of phase start timing and THI of throttle valve opening in step 521
Control is performed. Next, when the end of the torque phase is detected in step 521, the throttle valve opening is reduced by a predetermined value in step 525, and the shift shock prevention operation in the torque phase ends.

The determination of the torque phase end timing in step 521 is made based on whether or not the value of the determination value D has become D <0 in the above-mentioned equation (4).

[0064]

According to the invention described in each of the claims, the occurrence of the torque phase is actually detected at the time of the upshifting operation of the automatic transmission, and the engine output torque is increased accordingly, so that the engine output torque is increased. Thus, the engine output can be increased in accordance with the period of the torque phase, and the occurrence of a shift shock due to the torque phase can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment when the present invention is applied to an internal combustion engine for a vehicle.

FIG. 2 is a timing chart for explaining a conventional drive shaft torque fluctuation at the time of upshifting.

FIG. 3 is a diagram illustrating a principle of detecting a torque phase.

FIG. 4 is a timing chart for explaining a shift shock prevention operation of the embodiment of FIG. 1;

FIG. 5 is a flowchart specifically illustrating a shift shock prevention operation of the illustrated embodiment.

FIG. 6 is a diagram for explaining setting of constants used for the operation in FIG. 5;

FIG. 7 is a diagram illustrating setting of constants used for the operation in FIG. 5;

8 is a diagram illustrating setting of constants used for the operation in FIG.

FIG. 9 is a diagram illustrating setting of constants used for the operation in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 12 ... Intake passage 14 ... Throttle valve 20 ... Actuator 30 ... Electronic control unit (ECU) 40 ... Automatic transmission

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3D041 AA53 AC08 AC15 AD02 AD04 AD30 AD51 AE04 AF07 3G065 CA00 DA06 EA13 FA13 GA10 GA31 GA41 3G093 AA05 BA03 CB08 DA00 DA01 DA06 DB00 DB01 DB05 DB21 EA09 EC02 FA00 FA10 LA10 LC04 NC02 ND21 PA11Z PE01Z PE07Z PF08Z

Claims (3)

[Claims] 1. A throttle control device for an internal combustion engine having an automatic transmission, comprising: throttle valve driving means capable of changing a throttle valve opening independently of an operation of an accelerator pedal by a driver; A torque phase detecting means for detecting occurrence of a torque phase in which the output torque of the automatic transmission temporarily decreases after the start of the up-operation, and a torque phase is generated based on the start time and the end time of the detected torque phase. Control means for controlling a throttle valve opening change operation by the throttle valve driving means such that the engine output torque increases in accordance with a certain period. 2. The control means learns the actual start time of the torque phase detected by the torque phase detection means, and predicts the torque phase start time based on the learning result.
2. The throttle control device for an internal combustion engine according to claim 1, wherein the throttle valve opening change operation by the throttle valve driving means is controlled so that the engine output torque starts increasing in accordance with the predicted torque phase start timing. 3. The torque phase detecting means detects an actual start time and an end time of a torque phase based on an engine output torque change rate and an automatic transmission output torque change rate. 3. The throttle control device for an internal combustion engine according to claim 1.