JPH03182648A - Control device for engine with automatic transmission - Google Patents

Abstract

PURPOSE:To reduce the generation of a shock during lockup and to shorten a transfer time thereof by performing output torque down control of an engine when rotation of a drive shaft and that of a driven shaft are brought into a given relation during operation of a lockup mechanism. CONSTITUTION:A lockup mechanism to couple a drive shaft on the engine side directly to the driven shaft of a torque converter is provided. A control device for an engine with an automatic transmission is provided with a means to detect a given operation condition on which lockup is practicable, a means to detect the number of revolutions of the drive shaft on the engine side and that of the driven shaft of the torque converter, and a number of revolutions difference detecting means to detect a difference between the two numbers of revolutions by means of a detecting signal outputted therefrom. The engine with an automatic transmission is provided with a lockup control means to bring the lockup mechanism into a half lockup state on a given operation condition and when the number of revolutions is below a set value. In this engine, a control to perform output torque down control of an engine when rotation of the drive shaft and that of the driven shaft are brought into a given relation during operation of the lockup mechanism is provided.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a control device for an engine with an automatic transmission.
In particular, it relates to technology for optimizing lock-up of torque converters in automatic transmissions.

<Conventional technology> As a conventional automatic transmission for automobiles, under predetermined operating conditions (for example, when driving at high speeds above a certain vehicle speed, etc.), the drive shaft on the engine side and the driven shaft of the torque converter are connected via the torque converter. Some devices are equipped with a lock-up mechanism that directly connects the engine without using a torque converter to eliminate energy loss caused by going through a torque converter, thereby improving fuel efficiency.

By the way, in such conventional lock-up control, since the solenoid for operating the lock-up clutch of the lock-up mechanism is simply turned ON and OFF, a shock occurs when switching to the lock-up state, which causes damage to the drive shaft and driven shaft. There is a problem in that lock-up can only be performed when the rotational speed difference between the two is sufficiently small.

For this reason, as shown in Japanese Patent Application Laid-Open No. 60-34567, when the difference in rotational speed between the drive shaft and the driven shaft is less than the first set value, the lock-up solenoid is continuously turned on and off. There is a known system (smooth rota-up system? 11II) in which a lock-up solenoid is intermittently turned ON when the rotation speed is below a set value, thereby smoothly and quickly transitioning from a state where there is a difference in rotation speed to a lock-up state. .

<Problems to be Solved by the Invention> However, in such a conventional configuration, it takes a long time (for example, 4 to 5 seconds) from when lockup is determined until lockup is actually performed, and smooth lock amplifier control is difficult. However, the shock still remains when the contract is fully concluded.

Therefore, in view of the conventional problems as described above, the present invention provides a method to reduce the output torque of the engine when the rotation of the drive shaft and the rotation of the driven shaft reach a predetermined relationship when the lock-up mechanism is activated. The purpose of this is to reduce the shock during lock-up and shorten the lock-up transition time.

<Means for Solving the Problems> For this reason, the control device for an engine with an automatic transmission of the present invention, as shown in FIG. means for detecting a predetermined lock-up possible operating condition, means for detecting the rotational speed of the drive shaft on the engine side and the rotational speed of the driven shaft of the torque converter, based on the detection signal output from the means. an automatic transmission comprising a rotational speed difference detection means for detecting a difference between the two rotational speeds, and a lockup control means for bringing the lockup mechanism into a semi-lockup state when the rotational speed difference is less than or equal to a set value under predetermined operating conditions. The engine with the engine is configured to include a control means for reducing the output torque of the engine when the rotation of the drive shaft and the rotation of the driven shaft reach a predetermined relationship when the lock-up mechanism is activated.

<Operation> In such a configuration, when the lock-up mechanism is activated,
When the rotation of the drive shaft on the engine side and the rotation of the driven shaft of the torque converter reach a predetermined relationship, that is, when the lock-up transition state reaches a predetermined state, for example, the lock-up clutch that controls lock-up is fully engaged. By executing torque down control at the front, etc., it is possible to smoothly and quickly transition from a state where there is a difference in rotational speed between the engine drive shaft and the driven wheel of the torque converter to a lock-up state, thereby reducing the shock. The lockup transition time can also be reduced.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 2, an engine 1 mounted on a vehicle has a torque converter 2A connected to its output shaft, and a transmission 2B is further connected to the output shaft of the torque converter 2A. The automatic transmission 2 is constituted by the transmission 2B.

Fuel supply and ignition of the engine 1 are controlled by an engine control unit 3 containing a microcomputer. On the other hand, the automatic transmission 2 is provided independently of the engine control unit 3, and its gear shifting operation is controlled by the automatic transmission control unit 4 which also has a built-in microcomputer. There is.

Further, an accelerator opening sensor 5 for detecting the accelerator opening and a vehicle speed sensor 6 for detecting the running speed of the vehicle are provided, and these detection signals are sent to the control unit 3 for the engine and the automatic transmission, respectively. control unit 4.

The control unit 4 for the automatic transmission is equipped with a shift pattern that is set in advance in accordance with the vehicle speed and the accelerator opening. Based on the shift pattern, an automatic shift point is determined, the gear position of the transmission 2B is sensed, and an engine control request signal is output to the engine control unit 3 via the communication line 7.

Further, the automatic transmission 2 is equipped with a lock-up mechanism that directly connects the drive shaft on the engine side and the driven shaft of the torque converter 2A.

And, in the control unit 4 for automatic transmission,
In addition to the vehicle speed sensor 6, etc., there is an engine rotation speed sensor 8 as a drive shaft rotation speed detection means and a turbine rotation speed sensor 9 of the torque converter 2A as a driven shaft rotation speed detection means.
A detection signal from is input.

This control unit 4 controls a solenoid for operating the lock-up clutch of the lock-up mechanism under predetermined operating conditions and when the difference between the two rotational speeds is less than a set value, and brings the lock-up clutch into a half-lock-up state. A means for detecting a difference between the engine rotation speed sensor 8 and the turbine rotation speed sensor 9 based on detection signals from the engine rotation speed sensor 8 and the turbine rotation speed sensor 9 is provided in terms of software.

Further, the control unit 4 for the automatic transmission transmits information to the engine 1 via the communication line 7 to the engine control unit 3 when the rotation speed difference becomes less than or equal to a set value.
basic ignition timing setting means, retardation correction means, and ignition signal output means as means for retarding the ignition timing of the engine 1 when outputting the output torque down request signal;
is provided in the control unit 4 in terms of software.

The means for retarding the ignition timing of the engine 1 according to the engine rotational speed at that time is configured to retard the ignition timing of the engine 1 when the rotational speeds of the engine 1 reach a predetermined relationship based on the detection signals output from the rotational speed sensors. This corresponds to the control means of the present invention that performs output torque down control.

The control contents of this configuration will be explained based on the flowcharts of FIGS. 3 and 4.

FIG. 3 shows the control flow of the control unit 4 for automatic transmission.

In this flowchart, in step (hereinafter abbreviated as S as in the figure) 1, operating conditions such as vehicle speed and gear position are read and a lock-up region determination is executed. In S2, it is determined whether these operating conditions are suitable for lock-up, and if they are suitable for lock-up,
Proceeding to S3, it is determined whether or not the determination in S2 is the first time. If it is the first time, the process proceeds to S4, where both rotation speeds Ne and The NtO difference ΔN is detected, and the process proceeds to S5, where the duty ratio to be applied to the operating solenoid of the lock-up clutch of the lock-up mechanism is calculated according to the rotational speed difference N8, and the process proceeds to S6, where this duty ratio is output. to control the operation of the solenoid.

On the other hand, in S3, if the determination in S2 is not the first time, S
Proceeding to step 7, both rotational speeds Ne and Nt are determined based on the detection signals from the engine rotational speed sensor 8 and the turbine rotational speed sensor 9.
The difference ΔN is detected, and it is determined whether this difference is less than or equal to the set value N2. If this difference is larger than the set value (tiN□), it is determined that the torque down condition is not satisfied, and the process proceeds to S5. When the engine rotation speed Ne and the turbine rotation speed Nt become close to each other with the set value Nt being lower than the set value Nt, it is determined that the torque down condition is satisfied, and the process proceeds to S8 to send a torque down request signal to the engine side control unit 3. Output and S
5 and 56.

If it is determined in S2 that the lockup is not suitable, the process proceeds to S9, where lockup release control is commanded and the solenoid is turned off.

FIG. 4 shows the control flow of the control unit 3 on the engine side.

In this flowchart, in 311, it is determined whether a flag to be described later is 1 or 0, and if it is set to 0, S
Proceeding to step 12, it is determined whether or not a torque down request signal has been output to the engine side control unit 3. If the torque down request signal has been output, proceeding to step 513, a flag is set to 1, and step 514 is reached. Advance, XjlA when ignited
The DV retard correction amount (retard correction amount) is set, and if the torque down request signal is not output, proceed to S15.
The amount of retardation (retard) of the ignition timing ADV is set to 0, and the process proceeds to SI6. In 316, the ignition timing is determined from an ignition timing map (not shown), and in 317, the determined ignition timing is subjected to the retardation correction. MADV at the time of ignition is set by correcting according to the amount (retard correction amount).

On the other hand, if the flag is set to 1 in 311, the process proceeds to 318, where control is performed to reduce the torque down amount by a predetermined value, and the process proceeds to S19.

In S19, it is determined whether or not this torque down amount has become 0. If it is not 0, the process proceeds to 316; if it is O, the process proceeds to S20, where the flag is set to 0, and then the process proceeds to S16.
Proceed to.

A time chart of such control contents is shown in FIG.

According to this configuration, when a state in which there is a rotational speed difference between the drive shaft of the engine 1 and the driven shaft of the torque converter 2A is shifted to a lock-up state, if a predetermined lock-up transition state is reached, that is, the lock-up state is Since the ignition timing is retarded and the output torque of the engine 1 is reduced just before the up-clutch is fully engaged, there is a difference in the rotational speed between the drive shaft of the engine 1 and the driven shaft of the torque converter 2A. Since the state can be smoothly and quickly shifted from the lock-up state to the lock-up state, it is possible to reduce sluggishness and shorten the lock-up transition time.

In particular, in this embodiment, since the torque down control is configured to retard the ignition timing, there is an advantage that fine-grained control can be executed and there is no control delay.

Of course, as the torque down control, a configuration that performs fuel cut or a configuration that performs throttle valve control may be used.

In the above embodiment, when the difference between the two rotation speeds becomes equal to or less than the set value based on the detection signal output from the rotation speed detection means, the output torque of the engine 1 is controlled to be reduced. In the first invention, the ratio N e / N t of both rotation speeds is set based on the detection signal output from the rotation speed sensor 8.9 (when the ratio N e / N t becomes below iiA, the output torque reduction control of the engine It is also possible to have a configuration that performs the following.

In this case, the control unit 4 is provided with means for calculating the ratio N e /N t of both rotation speeds based on the detection signals output from the rotation speed sensors 8 and 9, and the control content is , 37 in Figure 3. S8
Instead, do as shown in Figure.

Furthermore, based on the detection signals output from both rotational speed sensors 8 and 9, the difference in the time differential values of the respective rotational speeds (dNe/d
t) - (dNt/d t) or ratio (dNe/d t
)/(dNt/dt) is the setting value B.

It is also possible to adopt a configuration in which the output torque of the engine 1 is controlled to be reduced when the torque becomes less than or equal to C.

In this case, the control unit 4 contains the difference (dNe/dt)-(dNt/dt) or ratio (dNe/dt) between the time differential values of both rotational speeds based on the detection signal output from the rotational speed sensor 8.9. dt)/(dNt/dt) is provided in software, and the control contents are as shown in FIGS. 7 and 8 instead of 37 and S8 in FIG. 5.

<Effects of the Invention> As explained above, according to the control device for an engine with an automatic transmission of the present invention, the difference in rotational speed between the drive shaft on the engine side and the driven shaft of the torque converter can be controlled under predetermined operating conditions. In a configuration in which the lock-up mechanism is brought into a semi-lock-up state when Since it is possible to perform this effectively, it is possible to reduce sluggishness, and it is also possible to shorten the lock-up transition time, which tends to be long, which is very useful.

[Brief explanation of drawings]

Fig. 1 is a claim correspondence diagram of the present invention, Fig. 2 is a system diagram showing an embodiment of the present invention, Figs. 3 and 4 are flowcharts explaining the operation of the same embodiment, and Fig. 5 is a diagram of the same A time chart for explaining the operation, and FIGS. 6 to 8 are diagrams showing step portions of a flowchart for explaining the operation of other embodiments, respectively.

Claims (1)

[Claims] It is equipped with a lock-up mechanism that directly connects the drive shaft on the engine side and the driven shaft of the torque converter. a rotation speed difference detection means for detecting a difference between the two rotation speeds based on a detection signal outputted from the means; In an engine with an automatic transmission, the engine includes a lockup control means that sometimes puts the lockup mechanism into a semi-lockup state, and when the lockup mechanism is activated, the rotation of the drive shaft and the rotation of the driven shaft have a predetermined relationship. 1. A control device for an engine with an automatic transmission, characterized in that the control device is provided with a control means for reducing the output torque of the engine when the