JPS61184268A - Lock-up controller of automatic transmission for vehicle mounting engine with fuel cut unit - Google Patents

Abstract

PURPOSE:To reduce fuel consumption by detecting for lock-up that the rotational speed difference between the input and output shafts of a torque converter becomes zero when a vehicle shifts from drive travelling to inertia one. CONSTITUTION:When a vehicle shifts from drive travelling to inertia one, an inertia travelling detecting means 8 commands an engine 1 to cut fuel when the engine has the rotational frequency in fuel-cut or more. then, when a rotational speed difference detecting means 7 detects on the basis of the outputs of the rotational speed difference between the input and output shafts becomes zero, a lock-up controlling means 9 commands a lock-up clutch 2 for lock-up. thus, fuel cut time can be elongated to the maximum limit to improve fuel consumption.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to a lock-up clutch of an automatic transmission equipped with a lock-up clutch used in a vehicle equipped with an engine equipped with a fuel cut device. The present invention relates to a lock-up control device that lengthens the time during which fuel supply is stopped and does not cause shock when the lock-up control device is engaged.

(Prior art) In recent years, due to the demand for improved fuel efficiency, fuel cut devices have been installed in vehicles to stop the fuel supply to the engine when the vehicle is coasting downhill or decelerating when the engine's driving force is not needed. It is often installed on the engine.

This fuel cut device is, for example, JP-A-56-5
As disclosed in Publication No. 0282, the inertia of the vehicle is detected by releasing the accelerator pedal, and if the engine speed is equal to or higher than the fuel cut speed when the inertia is detected, the fuel supply to the engine is cut off ( When the engine speed falls below the fuel recovery speed, the fuel supply to the engine is restarted (fuel recovery) to prevent engine stalling.

By the way, an automatic transmission system is equipped with an engine equipped with a fuel cut device as described above, and is equipped with a lock-up clutch that can appropriately put a torque converter into a lock-up state where its input and output elements are directly connected using power from the engine. Conventionally, in November 1981, the "Nissan Automatic Transmission with OD L4N7" published by Nissan Motor Co., Ltd.
1B type, E4N71B type maintenance manual J (A26100
4) As described on page 16 of Medium Temperature, when the idle switch is turned on when the accelerator pedal is released (
When the vehicle is running on inertia), lock-up is released regardless of the gear position of the automatic transmission.

(Problem to be Solved by the Invention) However, in such a conventional configuration, when the vehicle is running inertia, if the engine speed is equal to or higher than the fuel cut speed, the fuel is cut, but the lockup is released and the torque converter is placed in the converter state. As a result, as shown by the dashed line in Figure 4, the engine speed Ne drops rapidly, and the fuel recovery speed is increased compared to a vehicle equipped with a manual transmission to prevent engine stalling. Combined with this, the fuel cut time becomes extremely short, and there is a problem in that the effect of improving fuel efficiency due to the fuel cut cannot be sufficiently obtained.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and as shown in FIG. An input shaft sensor 5 detects the input shaft rotation speed and output shaft rotation speed of the torque converter 4 in a vehicle capable of driving through an automatic transmission 8 equipped with a lock-up clutch 2.
and an output shaft sensor 6, a rotational speed difference detection means 7 for detecting a rotational speed difference between the input and output shafts of the torque converter 4 based on signals from these sensors 5 and 6, and an inertia running detection means 8 of the fuel cut device. and a lock-up control means 9 that engages the lock-up clutch 2 when the rotation speed difference disappears when the vehicle moves backward from drive running to inertial running based on a signal from the rotation speed difference detection means 7. It is.

(Function) The rotational speed difference detection means 7 detects the opening of the rotational speed between the input and output shafts of the torque converter 4 based on the signals from the input shaft sensor 5 and the output shaft sensor 6, and outputs a signal corresponding to this speed difference. The signal is sent to the lockup control means 9.

The lock-up control means 9 checks the speed difference signal from the rotational speed difference detection means 7 when the inertial running detection means 8 detects the transition of the vehicle from drive running to inertial running and sends a signal to the control means 9. When the rotational speed difference disappears, the lock-up clutch 2 is engaged.

As a result, when the vehicle shifts from drive running to inertia running, the torque converter 4 is directly connected without causing a shock from engaging the lock-up clutch 2, which prevents a sudden drop in engine speed and lengthens the fuel cut time. can do.

Similarly, as described above, since the torque converter 4 is directly connected when the vehicle is running inertia, it also has the effect that engine braking can be applied sufficiently when braking is required.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows an embodiment in which the device of the present invention is configured by a microcomputer, and the microcomputer 10 includes a central processing unit 1-(CPU) 11, a memory 12, an input/output interface (I/10) 18, and a clock 14. This microcomputer 10 is used to detect the signal from the shift switch 15 that detects the shift position of the automatic transmission, and the temperature of the hydraulic fluid of the automatic transmission.
A signal from the TF temperature sensor 16, a signal from the vehicle speed sensor 17 that detects the vehicle speed, a signal from the idle switch 18 that turns ON when the accelerator pedal is released, a signal from the inhibitor switch 19 that detects range operation of the automatic transmission. , a signal from the kickdown switch 20 that turns on when the accelerator pedal is depressed to the maximum, a signal from the high throttle switch 21 that turns on when the throttle opening is near the maximum,
and the signals from the engine rotation speed sensor 22, respectively.

Then, the output of the microcomputer 10 is guided to the lock-up solenoid 28, and the lock-up solenoid 28 is operated and controlled based on the various signals mentioned above.

When the lock-up solenoid 28 is turned ON, the lock-up clutch is engaged and the torque converter is directly connected. FIG. It is assumed that the process is executed repeatedly, starting from step 30.

At the start, first the sensor 16,1? , 2.2 and switch 1
5, 18, 19, 20. Input the signals from 21, the vehicle speed obtained from the vehicle speed sensor 17, and the ATF temperature sensor 1
6, the gear position obtained from the shift switch 15 and the inhibitor switch 19, the throttle opening obtained from the kickdown switch 20 and the high throttle switch 21, the engine speed obtained from the engine speed sensor 22, and Whether the idle switch 18 is ON or not is stored in the memory 12, respectively.

Next, in step 81, the engine rotational speed N corresponding to the input shaft rotational speed and the output shaft rotational speed of the torque converter is determined.
Difference ΔN between e and turbine rotation speed Nt (turbine rotation speed Nt is obtained from the vehicle speed and shift position) (ΔN=Ne−N
t).

Furthermore, in step 32, the difference A between the ΔN found during the previous program execution (referred to as ΔN old) and the ΔN found this time is calculated.
(A = ΔN old - ΔN), and in step 88, the value of jN old is replaced with the current value of ΔN, and the memory 1 is
Store it in 2.

In step 84, it is determined whether the vehicle speed is 20 h/B or less, and if so, the process proceeds to step 85 and sets the lock-up flag FLu to 0. In step 86, the lock-up solenoid 28 is turned off and the heel program is activated. finish. Also, if the vehicle speed is not less than 2, step 37
It is determined whether the hydraulic oil temperature of the automatic transmission is 15° C. or lower, and if so, the flow advances to step 85. These steps 84 and 87 can prevent engine stalling due to low rotation of the engine or high viscous resistance of the hydraulic oil of the automatic transmission.

If it is determined in step 87 that the hydraulic oil temperature is not below 15°C, the process proceeds to step 88, where the table of lock-up conditions prestored in memo 1J12 (according to vehicle speed and throttle opening at each shift position) is entered. In step 89, it is determined whether the combination of shift position, vehicle speed, and throttle opening entered at the start corresponds to a lock-up condition.

Here, if the lock-up condition is not met, the process proceeds to step 35; if it is, the process proceeds to step 40, where it is determined whether the idle switch 18 is ON or not. If the idle switch 18 is not ON, the accelerator pedal is Since the engine is being stepped on, it is determined that the vehicle is driving while the engine is generating driving force, and the process proceeds to step 41. After setting the lock-up flag FLu to 1, the process proceeds to step 42, where the lock-up solenoid is turned on. , appears at the end of the program. As a result, when the vehicle is driving, the lock-up clutch can be engaged and the torque converter can be directly connected, thereby eliminating transmission loss of driving force and improving fuel efficiency.

Also, in step 40, the idle switch 18 is turned off.
When it is determined that it is N, it is determined that the vehicle is running inertia because the accelerator pedal has been released, and step 4 is executed.
8, it is determined whether the lock-up flag FLu is 1 (the lock-up clutch is engaged).

If FLu is 1 as a result of this determination, it can be left as is and the program ends. Also, as a result of discrimination, FLu is 1
If not, proceed to step 44 and calculate the rotational speed difference ΔN obtained in step 81 and the value obtained in step 32 that indicates whether ΔN becomes 0 after the rotation ram is executed between the previous and current program executions. , is large and terminates the program. Also, after proceeding and setting the lock-up flag FLu to 1, the lock-up solenoid is turned ON in step 42.
In step 44, which occurs at the end of the program, the lock-up solenoid 23 is turned on before a predetermined time period when the difference ΔN between the engine speed Ne and the turbine speed Nt becomes 0, thereby stopping the operation of the solenoid 23. This compensates for the time delay until the lock-up clutch is engaged, and obtains the rotational speed difference when the lock-up clutch is actually engaged. for example,
The program execution interval is 10 m5ec, and the value of B is 2.
If it is set to 0, the lock-up solenoid 28 can be turned on 0.2 seconds before the rotation speed difference ΔN becomes 0.

Through these steps 40 to 44, when the vehicle shifts from drive running to inertial running, the torque converter can be directly connected without causing a lock-up clutch engagement shock, and a sudden drop in engine speed can be prevented. When the accelerator pedal is released, the fuel cut device also operates, making it possible to lengthen the fuel cut time and significantly improve fuel efficiency.

Further, when braking is required, engine braking can be applied sufficiently, and the maneuverability of the vehicle can be improved.

The operating conditions of the apparatus of the above embodiment are shown by solid lines in FIG. 4 over time.

(Effects of the Invention) Thus, the control device of the present invention directly connects the torque converter 4 when the vehicle shifts from drive running to inertial running, thereby preventing a sudden drop in engine speed and lengthening the fuel cut time. This has the effect of significantly improving fuel efficiency, and since no shock is caused when the lock-up clutch 2 is engaged when the torque converter 4 is directly connected, the riding comfort is not impaired.

In addition, since it is directly connected to the torque converter when the vehicle is running inertia, even when braking is required for a long time, such as during a long descent, the engine brake can be fully utilized without having to be locked into a low gear. At the same time, it is possible to reduce the burden on the brakes and improve maneuverability.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a lock-up control device for an automatic transmission for a vehicle equipped with an engine equipped with a fuel cut device of the present invention. Fig. 2 is a system diagram showing an embodiment of the device of the present invention. A flowchart of the control program executed by the microcomputer, and FIG. 4 is a time chart showing the operating status of the same side device. 1... Engine with fuel cut device 2... Lock-up clutch 8... Automatic transmission 4... Torque converter 5... Input shaft sensor 6... Output shaft sensor 7.
・Rotational speed difference detection means 8 ・Inertia travel detection means 9 ・Lockup control means 10 ・Microcomputer 11 ・Central processing unit (CPU) 12 ・Memory 18 ・Input/output interface (I/.)14...
・Clock 15...Shift switch 16・
...ATF temperature sensor 17...vehicle speed sensor 18...
Idle switch 19...Inhibitor switch 20...Kick down switch 21...High throttle switch 22...Engine speed sensor 23...Lock-up solenoid patent applicant Nissan Motor Co., Ltd. Figure 1 Figure 3 JP-A-6L-184268 (6). Figure 4

Claims (1)

[Claims] 1.Equipped with inertial running detection means for detecting inertial running of the vehicle, and when the inertial running detecting means detects inertial running, if the engine rotational speed is equal to or higher than the fuel cut rotational speed, the fuel supply to the engine is cut off, and the engine rotational speed is reduced. The engine is equipped with a fuel cut device that restarts the fuel supply to the engine when the rotation speed becomes lower than the fuel recovery speed, and the torque converter is appropriately put into a lock-up state where input and output elements thereof are directly connected by power from the engine. An input shaft sensor and an output shaft sensor for detecting the input shaft rotation speed and the output shaft rotation speed of the torque converter, respectively, in a vehicle capable of driving through an automatic transmission equipped with a lock-up clutch, and from these sensors. A rotational speed difference detection means for detecting the rotational speed difference between the input and output shafts of the torque converter based on a signal from the inertial running detection means and a rotational speed difference detection means for detecting the rotational speed difference between the input and output shafts of the torque converter; A lock-up control device for an automatic transmission for a vehicle equipped with an engine equipped with a fuel cut device, further comprising a lock-up control means for engaging the lock-up clutch at the time when the rotational speed difference disappears during transition.