JPH0674331A - Control device for internal combustion engine with automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To provide a control device for an internal combustion engine with automatic transmission for a vehicle whereby, for instance, both lean burn control and lockup control can be simultaneously performed without worsening riding comfortableness and drivability of the vehicle. CONSTITUTION:At the time of LC capacity feedback control by the second ECU, when an engine is transferred to a lean burn control condition, in the case of calculating target ME values MEFB3, MEFB4, by subtracting a target engine speed increasing predetermined value DMELEAN from a value of multiplying a car speed Vn by a 3rd-speed coefficient K3FB or a 4th-speed coefficient K4FB (step S6, S10), connecting force of a lockup clutch is adjusted to a level of connecting force or less before a transfer to lean burn control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for an internal combustion engine equipped with an automatic transmission having a direct coupling means such as a lockup clutch, and more particularly to an automatic transmission in an internal combustion engine for performing lean burn control. The present invention relates to a control device for an internal combustion engine with an automatic transmission for a vehicle, which controls a fastening force of a direct coupling means.

[0002]

2. Description of the Related Art Conventionally, as a technique for improving fuel economy characteristics, an air-fuel ratio control method for controlling an air-fuel ratio of an air-fuel mixture supplied to an engine to a lean side from a stoichiometric air-fuel ratio in a predetermined engine operating state, There is so-called lean burn control technology. Further, by providing a lock-up clutch that connects the input side and the output side of the automatic transmission, and in a predetermined vehicle running state and engine operating state, the torque converter is directly connected by the lock-up clutch to achieve a power transmission effect. Widely used are automatic transmissions designed to improve the transmission.
As a method of controlling the engagement force of this lockup clutch,
A lock such as an LC capacity control method for controlling the engagement force of the lockup clutch, that is, the transmission capacity of the lockup clutch (hereinafter referred to as "LC capacity") by controlling the back pressure of the lockup clutch according to the running state of the vehicle. Up control is being performed. Further, in the above-mentioned LC capacity control method, for example, LC capacity feedback control is also performed in which the LC capacity is feedback controlled so that the slip ratio of the lockup clutch becomes the target slip ratio based on the traveling speed of the vehicle. It is being appreciated.

An internal combustion engine for a vehicle to which both the lean burn control and the lockup control are applied is also used.
The air-fuel ratio control and ignition timing control of the internal combustion engine including the lean burn control and the lockup clutch control are independent of each other. In such a case, if the torque converter is directly connected by the lockup clutch during the lean burn control, the load acting on the internal combustion engine increases, and the engine speed is increased by the lean burn control. Since it greatly decreases, the operation of the internal combustion engine tends to become unstable. Moreover,
In the direct connection state of the torque converter, torque fluctuations and vibrations caused by such instability of the operation of the internal combustion engine are directly transmitted to the vehicle, which causes a problem that the riding comfort and drivability of the vehicle deteriorate.

Lock-up control, for example, the above LC
When the air-fuel ratio control shifts to the lean burn control during the capacity feedback control, the rotation speed between the input and output of the lockup clutch decreases due to the decrease in the engine speed, that is, the decrease in the input side speed of the lockup clutch. The difference decreases. At this time, since the LC capacity is feedback-controlled to obtain the target slip ratio set before shifting to the lean burn control, the direct coupling ratio of the torque converter is desired at the time of shifting the lean burn. It will be larger than the value. For example, even if feedback control (slip control) is performed on the LC capacity so that the lockup clutch is slipped to some extent, the LC capacity becomes excessive due to a decrease in the engine speed when shifting to the lean burn control. The direct coupling ratio of the torque converter increases, and the torque converter is in the direct coupling state. As a result, torque fluctuations and vibrations resulting from the instability of the internal combustion engine as described above are directly transmitted to the vehicle, which causes a problem that the riding comfort and drivability of the vehicle deteriorate.

In order to solve such a problem, the following techniques have been proposed.

I) A lean burn control means for outputting a lean burn signal for performing a lean burn control within a predetermined lean burn control region, and a torque converter for an automatic transmission. -The lock-up mechanism provided in the torque converter and the torque converter in the lock-up mechanism within a predetermined lock-up area.
In a control device for an internal combustion engine with an automatic transmission, which comprises a lockup control means for outputting a lockup signal for putting the lockup signal into a lockup state, the lockup signal A control device that prohibits output, that is, prohibits the operation of the lockup mechanism during lean burn control (Japanese Patent Laid-Open No. 64-46062).

Ii) A control device for an automatic transmission for a vehicle, which releases a lockup clutch when changing a combustion state such as changing to a lean burn control state (Japanese Patent Laid-Open No. 62-200069). In this device, for example, when performing the lean burn control, the lean burn control is started after the lockup clutch is released (turned off).

Iii) When the lockup mechanism is on,
A control device for an internal combustion engine with an automatic transmission, which corrects a target air-fuel ratio of lean burn control to a small value or near a stoichiometric air-fuel ratio, that is, to a rich direction (JP-A-64-45933).
Issue).

[0009]

However, in the case of the above-mentioned prior arts i) to iii), it is possible to prevent deterioration of the riding comfort and drivability of the vehicle, but it is an effective fuel reduction technique. There is a problem in that it is not possible to utilize both the burn-in control and the lockup control at the same time, and the fuel consumption reduction effect is limited.

The present invention has been made to solve the above-mentioned problems of the prior art, and the purpose thereof is to:
An automatic gear shift for a vehicle capable of simultaneously changing the combustion state of an internal combustion engine and using a direct coupling means, such as both lean burn control and lockup control, without deteriorating the ride comfort and drivability of the vehicle. An object is to provide a control device for an internal combustion engine with an engine.

[0011]

In order to achieve the above object, in the present invention, a combustion state control means for controlling the combustion state of the internal combustion engine according to the operating state of the internal combustion engine, and the internal combustion engine Fluid transmission means that is connected to the output shaft of the internal combustion engine and that transmits the rotational force of the output shaft of the internal combustion engine through fluid, and direct connection means that connects the input side member and the output side member of the fluid transmission means with a fastening force. In a control device for an internal combustion engine with an automatic transmission for a vehicle, the combustion state change detecting means for detecting a change in the combustion state of the internal combustion engine, and the combustion state is changed according to the output of the combustion state change detecting means. And a fastening force adjusting means for adjusting the fastening force of the direct coupling means at that time to a magnitude equal to or less than the fastening force before the combustion state is changed.

In the above apparatus, the combustion state may be changed to a lean burn control state in which the air-fuel ratio of the air-fuel mixture is controlled to a target air-fuel ratio on the lean side of the stoichiometric air-fuel ratio.

Further, according to the present invention, the combustion state control means for controlling the combustion state of the internal combustion engine according to the operating state of the internal combustion engine, and the output shaft of the internal combustion engine are connected to each other through a fluid. The fluid transmission means for transmitting the rotational force of the output shaft of the internal combustion engine, the direct coupling means for coupling the input side member and the output side member of the fluid transmission means by the fastening force, and the rotation speed of the input side member of the direct coupling means A rotation speed detecting means for detecting, a target rotation speed determining means for determining a target rotation speed on the input side of the direct coupling means according to a running state of the vehicle and an operating state of the internal combustion engine, and an output of the rotation speed detecting means. The comparing means for comparing the output of the target rotation speed determining means, and the fastening force of the direct connecting means so that the rotation speed of the input side member of the direct connecting means becomes the target rotation speed according to the comparison result by the comparing means. Fastening with feedback control In a control device for an internal combustion engine with a vehicle automatic transmission having a control means, a combustion state change detecting means for detecting a change in a combustion state of the internal combustion engine, and the target according to an output of the combustion state change detecting means. Fastening by correcting at least one of the rotation speed and the comparison result so that the fastening force of the direct coupling means when the combustion state is changed is adjusted to be equal to or less than the fastening force before the combustion state is changed. And a force adjusting means.

The fastening force adjusting means may adjust the fastening force by increasing the target rotational speed by a predetermined amount. Further, the state in which the target rotation speed is increased by a predetermined amount may be maintained for a predetermined period.

Further, the engagement force adjusting means may decrease the increased target rotation speed by a predetermined amount after maintaining the state where the target rotation speed is increased by a predetermined amount for a predetermined period.

[0016]

In the control device for an internal combustion engine with an automatic transmission for a vehicle according to the present invention having the above structure, when the combustion state of the internal combustion engine is changed, the fastening force of the direct coupling means is set before the combustion state is changed. Since the magnitude is adjusted to be less than the force, even if the rotation speed of the output shaft of the engine is reduced by changing the combustion state, the direct coupling ratio of the direct coupling means is prevented from increasing more than necessary.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram showing a control device for an internal combustion engine with an automatic transmission for a vehicle according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a DOHC in-line 4-cylinder internal combustion engine in which each cylinder is provided with an intake valve and an exhaust valve (not shown). Is provided with a throttle body 3, and a throttle valve 301 is arranged inside thereof. Also, the throttle valve 30
A throttle valve opening (θTH) sensor 4 is connected to the first electronic control unit 1 and outputs an electric signal corresponding to the opening of the throttle valve 301 to output a first electronic control unit (hereinafter referred to as “EC
U ”) 5. The first ECU 5 is an engine control ECU that performs air-fuel ratio control, ignition timing control, and the like by controlling the amount of fuel supplied to the engine 1.

The fuel injection valve 6 is provided for each cylinder in the middle of the intake pipe 2 between the engine 1 and the throttle valve 301, is connected to a fuel pump (not shown), and is electrically connected to the first ECU 5. Connected to each other, and the first ECU 5
The valve opening time of the fuel injection valve 6 is controlled by the control signal from. The ignition plug 13 of each cylinder of the engine 1 is also electrically connected to the first ECU 5, and the ignition timing is controlled by the first ECU 5.

An absolute pressure (PBA) sensor 8 is provided on the downstream side of the throttle valve 301 of the intake pipe 2 via a branch pipe 7, and the intake wall temperature of the intake pipe 2 on the further downstream side is increased by the intake air temperature. The (TA) sensor 9 is attached. The PBA sensor 8 and the TA sensor 9 are respectively the absolute pressure PB in the intake pipe 2.
An electric signal according to A and an electric signal according to the intake air temperature TA are output and supplied to the first ECU 5.

An engine water temperature (TW) sensor 10 composed of a thermistor or the like is mounted on the cylinder peripheral wall filled with the cooling water of the cylinder block of the engine 1, and the TW sensor 10 has an electric power corresponding to the engine cooling water temperature TW. The signal is supplied to the first ECU 5.

Further, an engine speed (NE) sensor 11 and a cylinder discrimination (CYL) sensor 12 as a rotation speed detecting means are mounted around a cam shaft (not shown) of the engine 1 or around a crank shaft 20. The NE sensor 11 outputs a signal pulse (hereinafter referred to as “TDC”) at a predetermined crank angle position every 180 ° rotation of the crankshaft 20 of the engine 1.
Signal pulse "), and the CYL sensor 12 outputs a TDC signal pulse at a predetermined crank angle position of a specific cylinder. Each of these TDC signal pulses is the first EC
Supplied to U5.

Further, a wide range oxygen concentration sensor (hereinafter referred to as "LAF sensor") 16 is provided in the exhaust pipe 14 of the engine 1.
The LAF sensor 16 outputs an electric signal having a value substantially proportional to the oxygen concentration in the exhaust gas and supplies the electric signal to the first ECU 5.

The first ECU 5 shapes the input signal waveforms from the various sensors described above, corrects the voltage level to a predetermined level, and converts the analog signal value into a digital signal value. A central processing circuit (hereinafter referred to as "CPU") 5b, a storage unit 5c including a ROM and a RAM for storing various calculation programs executed by the CPU 5b, various maps to be described later, calculation results, and the like;
An output circuit 5d for supplying a drive signal to the fuel injection valve 6 and the spark plug 13 is provided. This first ECU 5
Plays a role as combustion state control means for controlling the combustion state of the engine.

On the other hand, the crankshaft 20 of the engine 1 has
The automatic transmission 21 is connected. The automatic transmission 21
A torque converter 22 connected to the crankshaft 20;
Pump blade 22a and turbine blade 2 of the torque converter 22
2b, a lockup clutch 23 as a direct connecting means, a gear mechanism 24 connected to the output side of the torque converter 22, and a hydraulic control circuit 25 for controlling the operations of the lockup clutch 23 and the gear mechanism 24. I have it. A gear position sensor 27 that detects the shift position of the automatic transmission 21 is provided.
Is output to the second ECU 35. This second E
The CU 35 is provided separately from the first ECU 5,
It is an ECU for an automatic transmission that performs various controls of the automatic transmission 21.

The hydraulic control circuit 25 controls the hydraulic pressure supplied to the lockup clutch 23 and the operating portion of the gear mechanism 24 by a solenoid (not shown) according to a control signal from the second ECU 35, whereby the lockup clutch 23 is operated. Control operation, LC capacity and gear position.

The output of the engine 1 is transmitted from the crankshaft 20 through the torque converter 22, the gear mechanism 24 and the differential device DF to the left and right drive wheels WL and WR to drive them. A vehicle speed sensor 28 that detects the vehicle speed V of the vehicle is provided on the output side of the automatic transmission 21, and the output of the vehicle speed sensor 28 is the second ECU 35.
Is supplied to.

The second ECU 35 is also the first ECU 5 described above.
Similarly to the above, the input circuit 5a, the CPU 5b, the storage means 5
c, and an output circuit 5d having the same function as the output circuit 5d, an input circuit 35a, a CPU 35b, a storage means 35c composed of a ROM and a RAM, and an output circuit 35d for supplying a drive signal to the hydraulic control circuit 25. . This second E
The CU 35 is a combustion state change detection means for detecting a change in the combustion state of the engine 1, in this embodiment, a change to the lean burn control state, a fastening force control means for controlling the fastening force of the lockup clutch 23, Target rotation speed of the input side of the torque converter 22 (MEFB3, MEFB4) described later
Target rotation speed determining means, comparing means for comparing the output (ME) of the NE sensor 11 with the target rotation speeds (MEFB3, MEFB4), and the engagement force of the lockup clutch 23 at the time of transition to lean burn control. It plays a role as a fastening force adjusting means for adjusting.

The outputs of the θTH sensor 4, TA sensor 9, TW sensor 10 and NE sensor 11 are also supplied to the second ECU 35.

The CPU 5b of the first ECU 5 performs various operations such as a feedback control operation area and an open-loop control operation area according to the oxygen concentration in the exhaust gas based on the above-mentioned various engine parameter signals. Of the TDC signal pulse based on the equation (1) in the basic mode and the equation (2) in the starting mode according to the engine operating state. The fuel injection time TOUT of the fuel injection valve 6 is calculated synchronously.

TOUT = Ti × KCMDM × KLAF × K1 + K2 (1) Here, Ti is set according to the basic fuel injection time of the fuel injection valve 6, specifically, the engine speed NE and the intake pipe absolute pressure PBA. Is the basic fuel injection time
The Ti map for determining the value is stored in the storage means 5c (RO
M).

KCMDM is a corrected target air-fuel ratio coefficient set by correcting the target air-fuel ratio coefficient KCMD corresponding to the target air-fuel ratio in consideration of the cooling effect of fuel injection and the like. The target air-fuel ratio coefficient KCMD is calculated based on the operating state of the engine (described later), and as is clear from the above equation (1), the fuel injection time TOUT increases as the target air-fuel ratio coefficient KCMD increases. That is, the KCMD value becomes a value proportional to the reciprocal of the air-fuel ratio, and when the KCMD value is smaller than a predetermined lean burn control determination value KCMDL which will be described later, the air-fuel ratio is in the lean state. Therefore, KCM
When D <KCMDL, it can be determined that the lean burn control is being performed.

KLAF is an air-fuel ratio correction coefficient, and is set so that the air-fuel ratio detected by the LAF sensor 16 matches the target air-fuel ratio during air-fuel ratio feedback control, and during open-loop control. It is set to a predetermined value according to the engine operating state.

K1 and K2 are other correction coefficients and correction variables calculated according to various engine parameter signals, respectively, and optimize various characteristics such as fuel consumption characteristics and acceleration characteristics according to the operating state of the engine. Is set to a predetermined value.

When the air-fuel ratio feedback control is performed, the target air-fuel ratio is usually set to a theoretical air-fuel ratio (14.7) or a value near the theoretical air-fuel ratio, but the engine 1 is brought into a predetermined operating state. At certain times, lean burn control is performed to set the target air-fuel ratio to the lean side (22.0) of the stoichiometric air-fuel ratio in order to reduce fuel consumption. The lean burn control method and the method of calculating the target air-fuel ratio coefficient KCMD include, for example, the method disclosed in Japanese Patent Application No. 2-414934.

On the other hand, the CPU 35 of the second ECU 35
b is the throttle valve opening θT supplied from the θTH sensor 4, the gear position sensor 27, the vehicle speed sensor 28, and the like.
A lockup control region for controlling the LC capacity of the lockup clutch 23 of the torque converter 22 is determined based on the engine operating state such as H, gear position, and vehicle speed V and the vehicle running state, and the determination result is determined according to the determination result. Then, the LC capacity of the lockup clutch 23 is controlled via the hydraulic circuit 25. In this LC capacity control, in the cruise range defined by the vehicle speed V and the throttle valve opening θTH, the engine speed NE is adjusted to the target speed L.
LC capacity feedback control for feedback controlling the C capacity is performed. That is, since the engine speed NE also changes according to the LC capacity, by controlling the LC capacity so that the engine speed NE becomes the target speed,
The slip ratio of the lockup clutch 23 is controlled to the optimum value.

When the air-fuel ratio control by the first ECU 5 shifts to the lean burn control during the LC capacity control by the second ECU 35, the engine speed NE decreases. When the LC capacity feedback control as described above is performed without considering this point, even if the LC capacity is controlled so that the engine speed NE becomes the target speed, even when the lean burn control is transitioned, Engine speed N
Due to the decrease of E, the engagement force of the lockup clutch 23 becomes larger than the target engagement force. Therefore, in the LC capacity feedback control according to the present embodiment, the target rotation speed is increased by a predetermined amount at the time of shifting to the lean burn control, that is, the target lockup clutch 23.
By increasing the slip ratio of the lock-up clutch 23, the engaging force of the lockup clutch 23 at the time of transition to the lean burn control is increased.
The force is controlled to be less than the fastening force before shifting to control.

The LC capacity feedback control will be described in detail below.

2 and 3 show the CP of the second ECU 35.
It is a flowchart which shows the main routine of LC capacity feedback control performed by U35b. This program is executed every predetermined period set by the timer.

First, in step S1, it is determined whether or not various conditions for performing LC capacity feedback control are satisfied. That is, the intake air temperature TA is a predetermined value (for example, -1
0 ° C. or higher, the cooling water temperature TW is a predetermined value (for example, 75
Or more), whether the vehicle speed V determined for each gear (gear position) is within a predetermined range (for example, 30 to 60 km / H), and the throttle valve opening θTH is set according to the vehicle speed. When the answer to whether or not it is within the predetermined range (for example, 10 to 15 °) is affirmative (YES) for a predetermined period of time, it is determined to be the LC feedback control region.

If the answer to step S1 is negative (NO), this program is terminated without performing LC capacity feedback control, and if affirmative (YES), the LC capacity feedback at the previous loop is performed. -It is determined whether or not the control mode is the feedback control mode (step S2). The answer is affirmative (YE
In the case of S), the process proceeds to step S3, and the target rotation speed increasing predetermined value DMELEAN is calculated. This DMELEA
N is the engine speed NE at the time of transition to lean burn control.
Is a predetermined value for decreasing the target value of the reciprocal ME of the above, that is, increasing the target rotational speed of the engine 1. The predetermined value DMELEAN for increasing the target rotation speed is calculated by executing the DMLEEAN calculation processing routine shown in FIG. 4, as will be described later.

Next, it is judged whether or not the gear position detected by the gear position sensor 27 is the fourth gear (step S4). If the answer is negative (NO), the gear position is the third gear. It is determined and the process proceeds to step S5. Here, step S
When the answer to No. 4 is negative (NO), it is determined that the third speed is selected. The LC capacity control program (not shown) prevents the LC feedback control from being performed when the gear position is the first speed or the second speed. This is because only 3rd speed or 4th speed is possible during LC capacity feedback control.

In step S5, the third speed coefficient K3FB is calculated in accordance with the throttle valve opening θTH and the like at the current loop in accordance with a predetermined relationship depending on the throttle valve opening θTH and the like indicating the engine load. . Next, the calculated third speed coefficient K3FB, the vehicle speed Vn during the current loop, and the target rotational speed increase predetermined value DME calculated in step S3.
The target ME value MEFB3 for the third speed is calculated by the mathematical expression (2) using LEAN (step S6).

MEFB3 = K3FB × Vn-DMELEAN (2) Subsequently, the target ME value MEF for the third speed MEF according to the equation (3).
The difference DMFB between B3 and the current ME value MEn is calculated (step S7).

DMFB = MEFB3-MEn (3) Next, the proportional control amount (P term) DP and the integral control amount (I term) DI of the output duty DOUT to the solenoid for LC capacity control of the hydraulic control circuit 25. KPF for calculating
As B and KIFB, constants KP3FB and KI3FB for the third speed, which are predetermined for each gear stage, are set (step S8), and the process proceeds to step S13.

On the other hand, the answer in step S4 is affirmative (YE
In the case of S), that is, when the gear position is the 4th speed, as in the case of the 3rd speed, the current loop time is set in accordance with a predetermined relationship according to the throttle valve opening θTH indicating the engine load. The fourth speed coefficient K4FB is calculated according to the throttle valve opening degree θTH and the like (step S9), and the fourth speed target ME value MEFB4 is calculated by the mathematical expression (4) (step S1).
0).

MEFB4 = K4FB × Vn-DMELEAN (4) Subsequently, the target ME value MEF for the fourth speed MEF according to Expression (5).
The difference DMFB between B4 and the current ME value MEn is calculated (step S11).

DMFB = MEFB4-MEn (5) Next, the proportional control amount (P term) DP and the integral control amount (I
Term) As coefficients KPFB and KIFB for calculating DI, predetermined constants for fourth speed KP4FB and KP4FB, respectively
Set I4FB (step S12), step S1
3 and proceed to S14.

In step S13, the P term DP and the I term DI are calculated according to equation (6) and step S14 according to equation (7), respectively.

DP = KPFB × DMFB (6) DI = DI + KIFB × DMFB (7) DI in the right side of the equation (7) indicates the I term DI calculated at the previous loop time.

Subsequently, the output duty DOUT to the LC capacity control solenoid for controlling the LC capacity of the lockup clutch 23 is calculated according to the equation (8) (step S15).

DOUT = DI + DP (8) Subsequently, the limit check of the calculated output duty DOUT is performed. That is, DOUT is the predetermined upper limit value D
It is determined whether or not it is larger than LMT (step S16),
The answer is no (NO), that is, DOUT ≤ DLMT
If it is, the process proceeds to step S18 without correcting the output duty DOUT, and if affirmative (YES),
That is, when the output duty DOUT> DLMT, the output duty DOUT is set to the upper limit value DLMT (step S17), and the process proceeds to step S18.

In step S18, it is determined whether or not the predetermined value DMELEAN for increasing the target rotation speed calculated in step S3 is greater than 0, and if the answer is affirmative (YES), that is, if DMELEAN> 0. , DMELE when calculating target ME values MEFB3, MEFB4
This is the case where the subtraction (increase of the target rotational speed NE) is being performed by AN, which is not suitable for learning the output duty DOUT which will be described later. Therefore, this program ends without learning DOUT. To do.

On the other hand, as will be described later, since the predetermined value DMELEAN for increasing the target rotation speed is set to a value of 0 or more,
If the answer to step S18 is negative (NO), DME
When LEAN = 0, that is, the target ME value MEF
This is a case where the subtraction (increase of the target rotational speed NE) by DMELEAN is not performed when calculating B3 and MEFB4.
Since it is appropriate to learn the output duty DOUT, the process proceeds to step S19 and thereafter, and the output duty DOU
Learn T.

First, in step S19, it is determined whether or not the gear position is the 4th speed. If the answer is negative (NO), that is, if the gear position is the 3rd speed, the current value DOU of the output duty is determined.
Using T, the learning value LREFFB3 for the third speed for calculating the output duty DOUT for LC capacity control in the area other than the cruise area is calculated by the equation (9) (step S20).

LREFFB3 = B / A × DOUT + (A
-B) / A * LREFFB3n-1 (9) A and B on the right side of the equation (9) are constants set in advance, and LREFFB3n-1 is 3 calculated in the previous loop.
The learning value for speed is shown.

On the other hand, the answer in step S19 is affirmative (YE
S), that is, when the gear position is the fourth speed, the formula (1
The learning value LREFFB4 for the fourth speed is calculated by 0) (step S21).

LREFFB4 = B / A × DOUT + (A
-B) / A * LREFFB4n-1 (10) LREFFB4n-1 on the right side of the equation (10) indicates the learning value for the fourth speed calculated in the previous loop.

Next, after performing a limit check on the learning values LREFFB3 and LREFFB4 calculated in steps S20 and S21 (step S22), each learning value LRE is checked.
The FFB3 and LREFFB4 are stored in the storage means 35c of the second ECU 35, and the present program ends.

If the answer to step S2 is negative (NO), that is, if the LC capacity feedback control is not performed at the previous loop and the LC capacity feedback control is performed this time, Output duty DOUT and I term DI at the initial stage of LC capacity feedback mode
As the learning value L for the third speed calculated by the time of the previous loop
REFFB3 or learning value LREFFB4 for fourth speed is set according to the gear position (steps S23 and S24), and DM
ELEAN is set to 0 (step S25), and the process proceeds to step S16.

In the above program, at the time of initial reset, the learning value LREFFB3 for the third speed and the learning value LREFFB4 for the fourth speed are respectively set to predetermined initial values LOREFFB.

Next, the DME executed in step S3.
The LEAN calculation processing routine will be described.

FIG. 4 is a flowchart showing a DMLEEAN calculation processing routine executed by the CPU 35b as so-called background processing.

First, in step S31, it is determined whether or not the current value KCMDn of the target air-fuel ratio coefficient KCMD is equal to or greater than a predetermined lean burn control determination value KCMDL. Here, the target air-fuel ratio coefficient KCMD is a value calculated by the CPU 5b of the first ECU 5 in the air-fuel ratio control program, and is usually a value set according to the engine speed NE and the intake pipe absolute pressure PBA. Illustrated KCMD
Although it is read from the map, it is appropriately corrected when the vehicle starts, when the water temperature is low, or when a predetermined high load operation is performed. Specifically, by executing a KCMD calculation routine (not shown), these values are calculated. It is set to a value that suits the operating conditions. This target air-fuel ratio coefficient KCMD is equal to the first ECU 5
From the second ECU 35 to the second ECU 35 and stored in the storage means 35c of the second ECU 35. Further, the predetermined value KCMDL for lean burn control determination is the theoretical air-fuel ratio (14.7).
A value corresponding to the air-fuel ratio on the leaner side (for example, the air-fuel ratio 18
Equivalent value), and as described above, the target air-fuel ratio coefficient K
CMD is the predetermined value KCMDL for this lean burn control determination
When it is smaller, it is determined that the engine 1 is in the lean burn control state.

The answer in step S31 is affirmative (YES),
That is, when KCMDn ≧ KCMDL, it is determined that the engine 1 is not in the lean burn control state, and the predetermined value DMELEAN for increasing the target rotation speed and the rotation speed increasing period nMELEAN (which will be described later) that is the timer value are set. It is set to 0 (steps S33 and S34), this program is terminated, and the process returns to the main routine (FIGS. 2 and 3).

If the answer to step S31 is negative (NO), that is, KCMDn <KCMDL, and the engine 1 is in the lean burn control state, the previous target air-fuel ratio coefficient KCMDn-1 is further reset. It is determined whether or not the value is equal to or more than the predetermined value KCMDL for the control for the control of the controller (step S3
2). If the answer in step S32 is affirmative (YES), that is, if KCMDn-1 ≧ KCMD, it is determined that the air-fuel ratio control state other than the lean burn control has shifted to the lean burn control state this time. , Rotational speed increase period nMEL
EAN is set to a predetermined value Tn (step S35), and the target rotation speed increasing predetermined value DMELEAN is set to a predetermined value DMELE.
After setting to ANH (step S36), this program is terminated and the process returns to the main routine (FIGS. 2 and 3). These predetermined values Tn and DMELENH are both values greater than 0, and are values that ensure that the lockup clutch 23 obtains an optimum slip ratio during the transition to the lean burn control state (for example, Tn = 2 sec. , DMEREANH =
(Value corresponding to 100 rpm increase in engine speed NE)
Is set to.

If the answers to both steps S31 and S32 are negative (NO), that is, if KCMDn <KCMDL and KCMDn-1 <KCMD, it is determined that the lean burn control is being performed both last time and this time. Step S
Proceeding to 37, it is determined whether or not the rotational speed increasing period nMELEAN is greater than zero. When the answer is affirmative (YES), that is, when nMELEAN> 0, the rotational speed increasing period nMELEAN is decremented by 1 (step S38), and the process proceeds to step S39.

On the other hand, the answer in step S37 is negative (N
O), that is, when nMELEAN ≦ 0, this rotation speed increase period nMELEAN is set to 0 (step S40), and the target rotation speed increase predetermined value DMELEAN is preset from the previous value by equation (11). The value obtained by subtracting the determined predetermined value DDLEAN is set as the current value of DMELEAN (step S41).

DMELEAN = DMELEAN−DDLEAN (11) DMELEAN on the right side of the equation (11) is the previous rule.
It is a predetermined value for increasing the target rotation speed calculated in the above.

Then, it is judged whether or not the calculated predetermined value DMELEAN for increasing the target rotation speed is larger than 0 (step S39), and the answer is affirmative (YES), that is, DM.
If ELEAN> 0, the program is immediately terminated and the main routine (FIGS. 2 and 3) is returned to. The answer to step S39 is negative (NO), that is, DMELEAN.
If ≦ 0, the process proceeds to steps S33 and S34,
After setting both the target rotational speed increasing predetermined value DMELEAN and the rotational speed increasing period nMELEAN to 0, this program is terminated and the process returns to the main routine.

FIG. 5 shows the predetermined value DME for increasing the target speed.
It is a figure which shows the time change of LEAN, and FIG. 6 is a target ME value MEF corresponding to the change of the said target air-fuel ratio coefficient KCMD.
FIG. 7 is a diagram showing changes in Bn, output duty DOUT, and the like. MEFBn shown in FIG. 6 represents the ME gear MEFB3 for the third speed MEFB3 or the target ME value MEFB4 for the fourth speed for convenience.

As can be seen from FIG. 5, the engine 1 is
At the time point t1 when shifting to the inverter control state, the target rotation speed increasing predetermined value DMELEAN is set to the predetermined value DMELEANH, and thereafter the value is held for the predetermined period Tn. After the time t2 when the predetermined period Tn has passed, the predetermined value DMELEAN for increasing the target rotation speed is the predetermined value DDLEEAN.
It gradually decreases and is set to 0 after time t3.

Therefore, as shown in FIG. 6, the target air-fuel ratio coefficient KCMD is the predetermined value KCMDL for the lean burn control determination.
When it becomes smaller, the target ME value MEFBn decreases by the maximum value DMELENH of the predetermined value for increasing the target rotation speed, and thereafter does not change for the predetermined period Tn, and the predetermined period Tn
After the lapse of time, increase by a predetermined value DDLEAN
It converges to the target ME value MEFBn before the transition to the inverter. That is, the target rotation speed of the engine 1 increases by a predetermined amount at the time of transition to the lean burn control, and after a predetermined period Tn has elapsed,
It will gradually decrease and converge to the original value. As a result, at the time of shifting to the lean burn mode, in order to reduce the LC capacity of the lock-up clutch 23 in response to the increase in the target rotation speed of the engine 1, the output duty DO for controlling the LC capacity is reduced.
UT decreases by a predetermined amount and then gradually increases to reach
Return to the value before control transfer.

The engagement force of the lock-up clutch 23 corresponding to the above LC capacity control will be described below.
When the engine control is transferred, the engine speed NE of the engine 1 decreases,
That is, since the engagement force of the lockup clutch 23 increases under the same LC capacity, even if the LC capacity of the lockup clutch 23 is reduced as described above, the actual engagement force of the lockup clutch 23 is the The fastening force will be the same as or smaller than that before the shift to the control.

As described above, in the above embodiment,
Even if the engine 1 shifts to the lean burn control state during the LC capacity feedback control, the lockup clutch 23
Is adjusted to a value equal to or less than the fastening force before the transition to the lean burn control, so that even if the engine 1 speed decreases due to the shift to the lean burn control, the lockup clutch It is possible to prevent the fastening force from increasing more than necessary. For example, in a region where the lock-up clutch 23 should be slip-controlled, the lock-up clutch 2 is reduced due to a decrease in the rotational speed of the engine 1 which causes a shift to lean burn control.
It is possible to avoid a situation where 3 is directly connected. Therefore, it is possible to perform both the lean burn control and the LC capacity feedback control at the same time without deteriorating the riding comfort and drivability of the vehicle. As a result, the fuel consumption characteristics can be significantly improved.

Further, in the above embodiment, the predetermined value DMELEAN for increasing the target rotational speed after the transition to the lean burn control is set.
Is decreased by a predetermined value DDLEAN, the target M
E value MEFBn is a predetermined value DMEL during lean burn control
After decreasing by EANH, it gradually increases and then returns to the original value. Therefore, after shifting to the lean burn control, the engine speed can be smoothly returned to the original value without causing torque fluctuation. The effect that it can be obtained is also obtained.

It should be noted that, after a certain period of time has passed after the transition to the lean burn control, the engine speed NE stabilizes, so the lean burn control is not performed without adjusting the LC capacity as described above. Both the normal LC capacity feedback control and the normal LC capacity feedback control can be performed at the same time.

The embodiment of the present invention has been described above.
The present invention is not limited to this, and various modifications can be made. For example, in the above embodiment, the case where the target ME values MEFB3 and MEFB4 of the engine 1 are corrected (increased) is taken as an example, but the engine speed used in the LC capacity feedback control and the target speed of the engine are It is also possible to adjust the LC capacity of the lockup clutch by correcting the comparison result (difference DMFB in the above embodiment). Further, in the above embodiment,
The target ME value (MEFB
3, MEFB 4) and the actual ME value (MEn) are used as an example, but a ratio may be used instead of the difference.

[0080]

As described above, in the control device for an internal combustion engine with an automatic transmission for a vehicle according to the present invention, even if the rotation speed of the output shaft of the engine is decreased by changing the combustion state of the engine,
Since the fastening force of the direct coupling means is prevented from increasing more than necessary, both the change of the combustion state of the engine and the use of the direct coupling means can be performed without deteriorating the riding comfort and drivability of the vehicle. It is possible to perform both the burn-in control and the lockup control at the same time. As a result, the fuel consumption characteristics can be significantly improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a control device for an internal combustion engine with an automatic transmission for a vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a main routine of LC capacity feedback control in the same embodiment.

FIG. 3 is a flowchart showing a main routine of LC capacity feedback control in the same embodiment.

FIG. 4 is a flowchart showing a DMLEEAN calculation processing routine in the LC capacity feedback control of FIGS. 2 and 3.

FIG. 5 is a predetermined value DMELEAN for increasing the target rotation speed.
It is a figure which shows the time change of.

FIG. 6 is a diagram showing changes in the target ME value MEFBn and the like corresponding to changes in the target air-fuel ratio coefficient KCMD.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Internal combustion engine (internal combustion engine) 5 1st ECU (combustion state control means) 11 NE sensor (rotation speed detection means) 20 Crankshaft (output shaft of internal combustion engine) 21 Automatic transmission 22 Torque converter (fluid transmission means) 22a Pump blade (input side member of fluid transmission means) 22b Turbin blade (output side member of fluid transmission means) 23 Lockup clutch (direct connection means) 35 Second ECU (combustion state change detection means, fastening force control means) , Target rotation speed determination means, comparison means, fastening force adjustment means)

Claims (6)

[Claims] 1. A combustion state control means for controlling a combustion state of the internal combustion engine according to an operating state of the internal combustion engine, and a rotation of the output shaft of the internal combustion engine connected to an output shaft of the internal combustion engine via a fluid. A controller for an internal combustion engine with an automatic transmission for a vehicle, comprising: a fluid transmission means for transmitting a force; and a direct coupling means for coupling an input side member and an output side member of the fluid transmission means with a fastening force. Combustion state change detection means for detecting a change in combustion state, and according to the output of the combustion state change detection means,
An automatic transmission for a vehicle, comprising: fastening force adjusting means for adjusting a fastening force of the direct coupling means when the combustion state is changed to a magnitude equal to or less than a fastening force before the combustion state is changed. Control device for internal combustion engine. 2. The change of the combustion state is performed by controlling the air-fuel ratio of the air-fuel mixture to a target air-fuel ratio on the lean side of the stoichiometric air-fuel ratio.
The control device for an internal combustion engine with an automatic transmission for a vehicle according to claim 1, wherein the control is a change to an inverter control state. 3. A combustion state control means for controlling a combustion state of the internal combustion engine according to an operating state of the internal combustion engine, and a rotation of the output shaft of the internal combustion engine connected to an output shaft of the internal combustion engine via a fluid. A fluid transmission means for transmitting a force, a direct coupling means for coupling the input side member and the output side member of the fluid transmission means by a fastening force, and a rotation speed detection means for detecting the rotation speed of the input side member of the direct coupling means. A target rotation speed determining means for determining a target rotation speed on the input side of the direct coupling means according to a running state of the vehicle and an operating state of the internal combustion engine; and an output of the rotation speed detecting means and the target rotation speed determining means. A comparing means for comparing the output and a fastening force for feedback controlling the fastening force of the direct coupling means so that the rotation speed of the input side member of the direct coupling means becomes a target rotation speed in accordance with the comparison result by the comparing means. Vehicle with control means In a control device for an internal combustion engine with an automatic transmission for a combustion state change detecting means for detecting a change in the combustion state of the internal combustion engine, according to the output of the combustion state change detecting means,
By adjusting at least one of the target rotational speed and the comparison result, the fastening force of the direct coupling means when the combustion state is changed is adjusted to be equal to or less than the fastening force before the combustion state is changed. A control device for an internal combustion engine with an automatic transmission for a vehicle, comprising: 4. The control device for an internal combustion engine with a vehicular automatic transmission according to claim 3, wherein the fastening force adjusting means adjusts the fastening force by increasing the target rotational speed by a predetermined amount. . 5. The control device for an internal combustion engine with an automatic transmission for a vehicle according to claim 4, wherein the engagement force adjusting means maintains a state in which the target rotation speed is increased by a predetermined amount for a predetermined period. 6. The fastening force adjusting means reduces the increased target rotation speed by a predetermined amount after maintaining the state where the target rotation speed is increased by a predetermined amount for a predetermined period. 5. The control device for an internal combustion engine with an automatic transmission according to claim 5.