KR0159578B1 - Fuel-cut control apparatus of automobile equipped with automatic transmission - Google Patents

Abstract

[purpose]

Fuel cut control device that prevents shock from increasing fuel resupply even with a coat converter

[Configuration]

The controller 8 performs a fuel cut to stop fuel injection from the injector group 6 to the engine I during the coasting run. When shifting from coasting to accelerated driving, the controller 8 first supplies the fuel for half of the cylinder at the half of the set time in the fuel resupply for releasing the above cut. Refuel the remaining half of the cylinder after the set time has elapsed. Therefore, even if the torque converter 11 is fastened, the shock at the time of fuel resupply can be alleviated, and a direct connection like a manual transmission can be obtained by fastening at the time of inertia to acceleration driving.

Description

Fuel cut control device of vehicle with automatic transmission

1 is a conceptual diagram showing a fuel cut control device for an automatic transmission mounted vehicle according to the present invention.

2 is a control system diagram of a vehicle power train showing an embodiment of a fuel cut control apparatus of the present invention.

FIG. 3 is a flowchart showing a fuel cut control program executed by the engine controller for reducing shock when fuel is resupplied in the example.

4 is an operation timing chart showing the fuel cut control.

* Explanation of symbols for main parts of the drawings

1: fuel cut engine 2: lock-up automatic transmission

3: accelerator pedal 4: throttle valve

5: air cleaner 6: injector group

7: ignition device 8: engine controller

9: intake air volume sensor 10: idle switch

11: lockup torque converter 13: transmission controller

14 throttle opening degree sensor 15 vehicle speed sensor

16: controller valve 17,18: shift solenoid

19: Lockup Solenoid

The present invention relates to a fuel cut control apparatus for a vehicle equipped with an automatic transmission.

The automatic transmission includes a torque converter having a torque increasing function and a torque fluctuation absorbing function in the electric system, but this torque converter cannot avoid the relative rotation between the input and output elements (slip of the torque converter) and the transmission efficiency is poor. For this reason, in the operating area (lock-up area) in which the torque increasing function and the torque fluctuation absorption function are unnecessary, the torque converter is often in the lock-up state where the input / output elements are directly connected.

On the other hand, since the engine driving the vehicle through such an automatic transmission does not require the engine output during inertia driving, which releases the accelerator pedal of the vehicle, the fuel cut device for stopping the fuel supply to the engine for the purpose of improving fuel economy. It is often provided with. The fuel cut device restarts the fuel supply of the engine by releasing the fuel cut at the time of shifting from inertia driving to accelerating driving of the accelerator pedal. The fuel cut is released to resume the fuel supply to the engine so as not to stop.

In a vehicle equipped with a power unit that is a combination of these fuel cut-mounted engines and a lock-up automatic transmission, the engine resumes supply of fuel when the fuel cut is released in response to the shift from inertia to accelerated driving. As a result of the sudden rise, large shocks and vibrations are likely to occur in the lock-up state of the torque converter.

In order to solve such a problem, conventionally, for example, as described in Japanese Patent Application Laid-Open No. 62-106174, when the fuel cut is released (fuel resupply), temporary lockup is released even in the lockup region to operate the torque converter in a converter state. A device has been proposed. In this case, the torque converter has a torque fluctuation absorbing function to mitigate shock and vibration during fuel resupply.

However, even in this lockup area, in the device for releasing the temporary lockup, the sense of direct connection such as the manual transmission required for the acceleration driving is lost, and the operationability is inevitably deteriorated.

An object of the present invention is to provide a fuel cut control device capable of reliably alleviating shock and vibration during fuel resupply even when the torque converter is in a locked up state.

For this purpose, the fuel cut control apparatus of the present invention, as shown in the concept of FIG. 1, provides engine power through an automatic transmission in which the torque converter is in a lockup state in which the input and output elements are directly connected in the lockup region. In a vehicle in which a fuel cut for stopping fuel supply to an engine is performed during the inertia of the vehicle transmitted to the drive wheel, the fuel cut when the fuel cut is released when the inertia of the vehicle is shifted from the inertia to accelerated driving. Stepped fuel resupply means was provided so as to increase the number of cylinders for releasing and to reduce the shock caused by the release of the fuel cut without resorting to the release of the lock-up state.

The automatic transmission sets the torque converter in the lock-up state in which the input / output elements are directly connected in the lock-up area, and otherwise sets the torque converter in the converter state in which the input / output elements are directly connected to each other, and drives the engine power through the torque converter. Can be used to drive the vehicle. While the vehicle is inertia running, the engine stops the fuel supply by the fuel cut control device, thereby improving fuel economy of the engine.

However, in the release of the fuel cut according to the transition from the inertia driving to the acceleration driving of the vehicle, the staged fuel resupply means causes the fuel cut to be released sequentially to the engine cylinder, thereby gradually increasing the output of the engine. Therefore, even when the torque converter is locked up in the lockup region, shock and vibration at the time of fuel resupply can be reliably reduced. Therefore, for the purpose of alleviating shock and vibration during this fuel resupply, it is not necessary to temporarily release the lockup of the torque converter even in the lockup area as in the prior art, and it is necessary to manually The loss of direct connection such as a transmission can be prevented, and countermeasures due to deterioration of driving performance are unnecessary.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described in detail based on drawing.

2 is an embodiment of the fuel cut control device of the present invention, 1 is a fuel cut engine, 2 is a lock-up automatic transmission.

The engine 1 includes a throttle valve 4 in which the opening degree is increased as the user presses the accelerator pedal 3, and the air cleaner 5 passes air in an amount proportional to the opening degree and the engine speed. Inhale. The engine 1 includes an injector group 6 and an ignition device 7 provided for each cylinder, and the engine 1 controls them by the engine controller 8. At this time, the engine controller 8 has a signal from the intake air amount sensor 9 that detects the engine intake air Q and a signal from the idle switch 10 which is turned on when the accelerator pedal 3 is released. Enter (I).

Based on these input information, the engine controller 8 injects a predetermined amount of fuel from the injector group 6 into a predetermined cylinder in accordance with the operation state of the engine 1, or stops the fuel supply during inertia driving. In addition, the engine controller 8 ignites the ignition plug of a predetermined cylinder at a predetermined timing through the ignition device 7 in accordance with the operation state of the engine, based on the above input information. In this way, the engine 1 is operated as predetermined, and inertia driving is fuel cut as predetermined.

The rotational power from the engine 1 is input to the automatic transmission 2 via the torque converter 11, which is lock-up, although not shown in detail. That is, in the operating area (lock-up area) in which the torque increasing function or the torque fluctuation absorption function of the torque converter is unnecessary, the torque converter 11 is in a lock-up state in which input / output elements are in series. It is assumed that the lockup is released. The automatic transmission 2 shifts the engine power input via such a torque converter 11 to a gear ratio corresponding to the selected shift stage and transmits it to the drive wheel 12.

The speed control of the automatic transmission 2 and the lock-up control of the torque converter 11 are performed by the transmission controller 13. To this end, the transmission controller 13 has a signal from the throttle opening degree sensor 14 for detecting the opening degree TH of the throttle valve 4 and a signal from the vehicle speed sensor 15 detecting the vehicle speed V. FIG. Enter. The transmission controller 13 finds an appropriate shift stage suitable for the operating state from the throttle opening degree TH and the vehicle speed V, and turns on and off the shift solenoids 17 and 18 of the controller valve 16 so that this is achieved. Is determined, and the shift to the appropriate shift stage is performed. The transmission controller 13 also checks whether the torque increasing function or the torque fluctuation absorbing function of the torque converter 11 is unnecessary in the operating area (lock-up area) from the input information, so that the controller valve 16 in the lock-up area. The lock-up solenoid 19 is turned on to turn the torque converter 11 into a lock-up state in which input / output elements are directly connected. Otherwise, the torque converter 11 is turned off by turning off the lock-up solenoid 19. Shall be.

However, the engine controller 8 and the transmission controller 13 assume that the respective control output signals exchange input information with each other from the beginning. In particular, the engine controller 8 executes the control program of FIG. 3 to cause the fuel cut control to be aimed at by the present invention.

3 is executed repeatedly each time a cylinder signal for each predetermined rotation angle of the engine 1 is input. First, in step 21, the signal I and the transmission controller 13 from the idle switch 10 are executed. The lockup signal to solenoid 19 is read. Next, in step 22, it is checked from the signal I whether the idle switch 10 is OFF, that is, whether the accelerator pedal 3 is in a depressed state. In the release state of the accelerator pedal 3 (the inertia running), the above-described normal fuel injection control including the fuel cut is performed in step 23. However, since the engine output is unnecessary in this inertia driving, fuel injection to the engine 1 is stopped by the fuel cut to improve fuel economy.

The accelerator pedal 3 is in a stepped state, and whether or not the idle switch 10 was ON last time from the previous value of the signal I in step 24 (that is, the accelerator pedal 3 was in the last step release state). It is checked whether or not it has shifted from inertia driving to acceleration driving. At the time of this transition, it is determined in step 25 whether the torque converter 11 is locking up. In this determination, the engine controller 8 receives the signal from the transmission controller 13 to the solenoid 19 and does this. If it is not locked up, since fuel cut control by this invention is unnecessary, control advances to step 23, and normal fuel injection corresponding to the stepped state of the accelerator pedal 3 is performed.

If it is during lockup, it is checked in step 26 whether it is an electric cylinder fuel cut, and even if it is not during an electric fuel cut control, since fuel cut control by this invention is unnecessary, control is performed in step ( 23, normal fuel injection corresponding to the stepped state of the accelerator pedal 3 is executed.

If it is during the electric fuel cut, in step 27, the resupply plug RFLG indicating the release of the fuel cut (during fuel resupply) is turned on for the purpose described later, and in step 28 the subtraction timer T The set time Ts is set at), and the electric cylinder fuel cut is continued at step 29.

In the case where it is determined that the acceleration driving continues in step 24, it is checked in step 30 whether the plug RFLG is ON or not while cutting the fuel. During the fuel cut, half of the set time Ts has elapsed from the transition time t ₁ as described in FIG. 4 based on the determination of the subtraction timer T at steps 31 and 32. until it continues the electric cylinder fuel cut by the execution of the step (29), and instantaneous to the half of the setup time (Ts) has elapsed (t _2), the release of fuel cut for a two-cylinder in half in step 33 ( refueling) and to the fuel material supplying electric cylinder to release also the fuel-cut of the remaining two cylinders in step 23 via the step 34, the instantaneous (t ₃₎ for setting time (Ts) has elapsed.

Then, in step 34, the plug RFLG is set to 0, and then control proceeds from step 30 to step 23, from the above-described unusual fuel resupply control to normal fuel injection. Return

Therefore, as shown in FIG. 4, in the fuel resupply according to the shift from the inertia run to the accelerated run, the engine output is not supplied to the engine at once but the fuel is resupplyed in half cylinders sequentially. As a result, the transmission output torque is also gradually increased as shown in FIG. 4, so that shock and vibration during fuel resupply can be alleviated even when the torque converter is locked up. Thus, in order to alleviate fuel resupply shock and vibration, it is not necessary to release the lock up of the torque converter once in the transition from inertia driving to acceleration driving, even in the lockup area. Direct connection to the transmission can be secured.

In the above-described example, the fuel is re-supplied in half cylinders. However, when the fuel is re-supplied in one cylinder, the control is complicated, but the softer fuel resupply provides the above shock reduction effect and vibration control effect. It can be increased further.

In this way, the fuel cut control device of the automatic transmission mounted vehicle according to the present invention has a configuration in which the fuel resupply according to the shift from inertia driving to accelerated driving is sequentially performed for a plurality of cylinders of the engine, so that the torque converter is locked up. Even if it is in a state, the shock and vibration at the time of refueling can be alleviated.

As a result, in order to alleviate fuel resupply shock and vibration, it is not necessary to release the lock of the torque converter once in the transition from inertia driving to acceleration driving, even in the lockup region. At the time of implementation, a direct connection such as a manual transmission can be secured.

Claims (1)

A fuel cut is performed to stop the fuel supply to the engine during the inertia of the vehicle that transmits the engine power to the drive wheels through an automatic transmission in which the torque converter is in a lockup state in which the input / output elements are directly connected in the lockup area. In a vehicle that is intended to be used, the number of cylinders for releasing the fuel cut is increased when the fuel cut is released when the vehicle is inertia running to accelerated driving, and the fuel is not relied on the release of the lock-up state. A fuel cut control apparatus for a vehicle with an automatic transmission, comprising: a staged fuel resupply means for reducing shock due to release of a cut;