JPS61249840A - Fuel-cut controller - Google Patents

Abstract

PURPOSE:To prevent shock vibrations in a car body caused by a sudden reduction in engine output torque from occurring, by controlling the starting timing of both lockup and fuel cut motions of an automatic transmission-cum-lockup in a proper manner. CONSTITUTION:A fuel-cut controller 3 is connected to an engine of a car mounted with an automatic transmission-cum-lockup 1. And, first operating conditions for a lockup motion a a time when a condition performing the lockup motion is satisfied is judged by a lockup motion judging device 4 in the controller. And, when it is judged as in the lockup motion, a release command of the lockup motion is emitted by a relase command generating device 5. Afterward, successively a fuel-cut motion takes place late in generation of the release command by a fuel-cut motion delaying device 6. In consequence, the fuel-cut motion is accurately and properly controlled, thus a large torque variation is preventable from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel cutter control device that appropriately controls the start timing of a lockup operation of an automatic transmission and a fuel cut operation of an engine.

(Prior Art) Conventionally, in a vehicle equipped with an automatic transmission with lock-up, as shown in Japanese Patent Application Laid-Open No. 60-1464,
In order to reduce the shock caused by torque fluctuations during fuel recovery, a control device has been proposed that performs related control between lock-up operation and fuel recovery operation.

(Problem to be Solved by the Invention) As in the conventional example 5 above, in a vehicle equipped with an automatic transmission with lockup, the lockup operation, door knee cut operation, or fuel recovery operation is not controlled in a well-related manner. This may cause unnecessary torque fluctuations.

For example, if the lock-up operation is performed because the vehicle is traveling at high speed, and the accelerator pedal is released to decelerate and the fuel cut operation is performed, if the lock-up operation continues, the lock-up operation will suddenly occur. This decrease in engine output is directly transmitted to the output shaft of the torque converter, resulting in torque fluctuations and a shock that causes the vehicle body to jerk.

In addition, even if the lock-up operation is canceled at the same time as the start of the fuel cut operation to prevent this shock, the lock-up operation is controlled by the hydraulic circuit, so the lock-up operation time is longer than the fuel cut operation time. It takes a long time to release, so
The fuel cut operation is performed before the lock-up operation is completely released, and although it is for a short time,
Large torque fluctuations occur.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes means shown in FIG.

The fuel cut control device 8 of the present invention controls the 721-el cut operation of the engine 2 of a vehicle equipped with an automatic transmission with lock-up l, and includes a lock-up operation determining means 4, a release command generating means 5, , a fuel cut operation delay means 6 is provided.

The lock-up operation determining means 4 determines whether or not the lock-up automatic transmission 1 is undergoing a lock-up operation when the conditions for performing a fuel cut operation are satisfied.

The release command generating means 5 issues a release command for the lock-up operation when the lock-up operation determining means 4 determines that the lock-up operation is in progress when the conditions for performing the fuel cut operation are satisfied.

The fuel cut operation delay means 6 performs the fuel cut operation after the lock-up operation release command is issued.

(Function) With the above configuration, when the fuel cut operation is performed during the lock-up operation, the present invention generates a lock-up operation release command and then performs the fuel cut operation with a delay, thereby ensuring that the lock-up operation is performed reliably. After the release of the operation is completed, the 721 L cut operation is performed, and it is possible to prevent large torque fluctuations from occurring.

(Example) FIG. 2 shows the configuration of a first embodiment of the present invention.

The revolution unit 18 is a control device that controls fuel cut operation, and the lockup control unit 14 is a control device that controls lockup operation.

The revolution unit 18 receives an output signal S0 of the idle switch 10 inputted via the timer circuit 12, an output signal S2 corresponding to the engine speed given from the ignition coil 17, and other outputs of an inhibitor switch (not shown). Based on the signal, etc., it is determined whether the conditions for performing the fuel cut operation are satisfied or not, and when the conditions for performing the fuel cut operation are satisfied, a signal S for closing the slow cut solenoid valve 15 is output. .

As shown in FIG. 8, the slow cut solenoid valve 15 is provided in the carburetor 20 to supply and stop fuel.

The idle switch 10 becomes ICON when the throttle valve 21 is closed, and is used to detect that the engine is in an idling state or that the accelerator pedal is released.

The lock-up control unit 14 determines whether the conditions for performing the lock-up operation are satisfied based on the output signal S2 of the idle switch IO and the output signal S8 of the water temperature switch 11, and determines whether the conditions for performing the lock-up operation are satisfied. When the lock-up solenoid 16
It outputs a signal S for activating.

The lock-up solenoid 16 is 1 as shown in FIG.
The lock-up control valve 28 is provided in the hydraulic circuit of the torque converter 22 equipped with a zero-turn-up mechanism.
Switch the operating state of the button to activate and release the lip-up operation. Note that 24 is a vehicle speed cut valve, Pa is 8th gear line pressure, Po is converter pressure, Pt is line pressure, and Pg is governor pressure.

The revolution unit 18 and lockup control unit 14 each perform known control operations.

Furthermore, the device of this embodiment can perform the following operations by the function of the timer circuit 12.

For example, when the accelerator pedal is released while the lock-up operation is being performed when driving in 8th gear, and coasting driving is started, the idle switch 10 is turned on with the release of the accelerator pedal, and the output signal S0 is set to a high level. to a lower level.

In response to this change in the output signal S0, the lock-up control unit 14 generates a command signal to cancel the lock amplifier operation, and the lock-up solenoid 16
The output of the activation signal S is stopped.

When the output of the operating signal S stops, the lock-up operation starts to be released, but due to the delay in the hydraulic system, the lock-up operation will not be completed until a predetermined period of time elapses after the output of the operating signal S stops. is not canceled.

On the other hand, in response to the fall of the output signal S0 of the idle switch IO, the timer circuit 12 is activated and supplies a high level signal to the revolution unit 18 after a predetermined period of time has elapsed. That is, the timer circuit 12 outputs the output signal S0
It functions to delay the fall of the signal by a predetermined period of time and supply it to the revolution unit 18.

The time Tm measured by the timer circuit 12 is set approximately equal to the operation delay time Td required to release the lock-up operation (Tm≧Td).

The revolution unit 1B outputs a signal S4 for closing the slow cut solenoid valve 15 in response to the input of the high level signal from the timer circuit 12, and performs a fuel cut operation.

In this way, in this embodiment, when a fuel cut operation is performed during a lock-up operation, the fuel cut operation is performed after a predetermined period of time has elapsed after a lock-up operation release command is issued. It is possible to completely avoid the occurrence of a period in which a sudden drop in engine output accompanying a cut operation is directly transmitted to the output shaft of the torque converter.

In this embodiment, the operation for determining whether or not a lock-up operation is being performed when performing a fuel cut operation is as follows:
This corresponds to the operation of the timer circuit 12.

Next, a second embodiment of the present invention will be described.

This embodiment has a more advanced function performed by the timer circuit 12 used in the first embodiment, and the timer circuit 12 shown in FIG. 2 is replaced with a lock-up circuit shown in FIG. 6. A feature is that an operation cancellation detection circuit 25 is provided.

This lock-up operation release detection circuit 25 includes an input shaft rotation sensor 26 that detects the rotation number (or rotation speed) N8 of the input shaft (i.e., engine output shaft) of the torque converter 22 equipped with the lock-up mechanism shown in FIG. and,
An output shaft rotation sensor 27 detects the rotation speed (or rotation speed) NT of the output shaft of the converter 22, and an input shaft rotation speed NF.

and an AND gate 29 that generates an AND signal of the output 86 of the comparison circuit 28 and the output signal S□ of the idle switch 1O. The comparison circuit 28 has N8<N
The configuration is such that a high level signal is output when T is reached.

By providing this lock-up operation release detection circuit 25, the present embodiment performs the following operations during coasting driving.

When the accelerator pedal is released in the driving state where the lock-up operation is being performed and the coasting operation is started, the idle switch 10 is turned on with the release of the accelerator pedal, and the output signal S0 changes from a low level to a high level. .

In response to the fall of the output signal 8□, the lock-up control unit 14 issues a lock-up operation release command, and the lock-up solenoid 16 receives an activation signal S.
5. Stop the output. As a result, release of the lock-up operation is started.

On the other hand, the high level output signal S1 input to the lockup operation release detection circuit 25 is input to the AND gate 29.

At the time when the idle switch IO is turned ON, the lock-up operation is still being performed, so the input and output shafts of the torque converter 22 are directly connected, and the NE -
It is Nrr. Then, when the lock-up operation is released by the lock-up control unit 14, NE<NT, so at this time, the output S6 of the comparison circuit 28 changes to a high level, and the output S of the AND gate 29 changes to a high level. becomes.

In response to the rise of the output S7 of the ANDG)'B9, the revolution unit 1B performs a fuel cut operation.

As described above, in this embodiment, when the 1 fuel cut operation is performed during the lock-up operation 5#h, the input shaft rotation speed NF of the torque converter changes to the output shaft rotation speed after the release command for the cut-up operation is generated. Since it became smaller than several NT, we confirmed that the lock-up operation was completely released,
By performing the fuel cut operation after this, it is possible to almost completely eliminate the possibility that the fuel cut operation will be performed during the lockup operation.

In this embodiment, the operation for determining whether or not a lock-up operation is being performed when performing a fuel cut operation is an AND operation.
This corresponds to the operation of gate 29.

It goes without saying that the operations in each of the above embodiments can be performed by a control circuit using a microcomputer.

(Effects of the Invention) As described above in detail, the present invention provides that when a fuel cut operation is performed during a lock-up operation, the fuel cut operation is performed after a lock-up operation release command is generated. Therefore, the fuel cut operation is performed after the lock-up operation has been completely released, and the sudden decrease in engine output torque that accompanies the fuel cut operation is directly transmitted to the output shaft of the torque converter and to the vehicle body. Shock vibrations can be reliably prevented from occurring.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of the present invention, Figure 2 is a configuration diagram of the first embodiment of the invention, Figure 8 is a layout diagram of the slow cut solenoid pulp in Figure 2, and Figure 4 is in Figure 2. FIG. 5 is a block diagram showing a part of the configuration of a second embodiment of the present invention. L...Automatic transmission with load-up 8...Fuel cut control device 4...Lock-up operation determination means 5...Release command generation means 6...Fuel cut operation delay means lO...Idle switch 12 ...Timer circuit (lock-up operation determining means and fuel cut operation delay means) 18...Revolution unit 14...Lock-up control unit 15...
- Slow cut solenoid valve 16...Lock-up solenoid 22...Torque converter 25 with lock-up mechanism...Lock-up operation release detection circuit (lock-up operation determining means and fuel cut operation delay means) Patent applicant Nissan Motor Co., Ltd. Company Figure 3 IQ Figure 4

Claims (1)

[Scope of Claims] 1. In a fuel cut control device that controls a fuel cut operation of a vehicle equipped with an automatic transmission with lockup, when a condition for performing the fuel cut operation is satisfied, the automatic transmission with lockup A lockup operation determining means for determining whether or not a lockup operation of the transmission is being performed; and a lockup operation determining means that determines that the lockup operation is being performed when a condition for performing a fuel cut operation is satisfied. a release command generating means that issues a command to release the lock-up operation when the release command is determined; and a fuel cut that performs a fuel cut operation with a delay after the release command generation means generates the release command for the lock-up operation. A fuel cut control device comprising an operation delay means.