JPS62261628A - Fuel cut control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent an excessive torque from being transmitted to the driving system of a vehicle by providing a fuel cut means which cuts off the fuel to be supplied to an engine, and a fuel cut revolution reducing means which sets the fuel cut revolution to a lower revolution at a specific time. CONSTITUTION:In a distributor 41, a revolution sensor 43 which detects the number of revolutions is provided. A control device 50 has a fuel cut revolution reducing means which sets the fuel cut revolution to a revolution lower than the fuel cut revolution at the time of normal operation when the shift operation from a stop range to a running range is detected by a shift operating means. A fuel injection valve 38 through which the fuel is forcibly fed to a fuel pump 37 from a fuel tank 35 is injected to the supplied by a prescribed quantity is fitted in the vicinity of an intake valve 7. Thus, an excessive torque can be prevented from being transmitted to the driving system of a vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for supplying fuel to an internal combustion engine under predetermined conditions when shifting a J3 shift lever from a stop range to a drive range in an automobile equipped with an automatic transmission. The present invention relates to a fuel cut control device for an internal combustion engine that cuts the fuel temporarily.

BACKGROUND ART A fuel cut device is known that cuts the fuel supplied to the engine when the engine speed exceeds a predetermined speed for the purpose of preventing overheating of the catalyst in the exhaust system of an internal combustion engine and reducing fuel consumption. (El: I manual, Toyota Motor Corporation)
issue).

In this case, the fuel cutter 1- stops fuel injection from the fuel f1 injector when the engine speed exceeds a predetermined value when the throttle sensor detects the closed position of the throttle valve, and To prevent engine overrun,
When the engine speed exceeds a predetermined speed, fuel injection from the fuel injection valve is stopped.

By the way, when starting a car with an automatic transmission from a stopped position, an experienced driver would move the shift lever from a stop range such as N (neutral) or P (parking) to D (dryce) etc. Normally, while driving, shift to the front and then step on the actuator rubedal.

Problems that the invention attempts to resolve However, if a driver is not used to driving a car with an automatic transmission or is a novice, it is difficult to press the accelerator pedal when starting and move the shift lever from the stop range while the engine is rotating at high speed. There is a risk of shifting into the driving range, and in this case, there is a problem that a relatively large output torque of the engine will be transmitted to the automatic transmission and burn out the clutch device of the transmission in the vehicle drive system.

The purpose of the present invention is to solve these problems, that is, to prevent damage to the automatic transmission, etc., which is likely to occur when the engine is in a high speed range when the engine is shifted from the stop range to the drive range. There is a particular thing.

In order to solve the above problems, the internal combustion of the present invention=tii
The fuel cut control device of Il is as shown in Fig. 1.
When the engine speed exceeds the fuel cut speed, the fuel cut means that cuts the fuel supplied to the engine and the left lever of the automatic transmission to which the engine output is transmitted shift from the stop range to the drive range. When a shift operation from the stop range to the drive range is detected by the shift operation detecting means for detecting 9 when the shift operation is performed, and the shift operation detecting means detects the shift operation from the stop range to the driving range, the fuel cut rotation speed is set to the fuel cut speed during normal operation. i
・Crystal material cut-off reduction means for setting the number of revolutions to be 6 times lower than the number of revolutions.

L-m1 According to the present invention, when the shift lever of the automatic transmission is in the stop range, the fuel cut rotation speed is set to the fuel cut rotation speed during normal operation.

Next, when the shift lever is shifted from the stop range to the drive range, the fuel cut rotation speed is set to a lower rotation speed than the fuel cut rotation speed during normal operation.

Shil; GattetaI! When I is switched from the stop range to the running range when I is in the high speed range, the engine speed detected by the speed detection means is higher than the fuel cut speed, and the fuel is supplied to the engine by the fuel cut means. is cut. Therefore, the engine speed is rapidly reduced,
This prevents excessive torque from being transmitted to the vehicle's drive system. -Example An example of the present invention will be described based on the drawings.

FIG. 2 shows an internal combustion engine I to which the fuel cut control device of the present invention is applied.
An example of a schematic configuration of allQ is shown.

In the figure, 1 is the internal combustion engine body installed in a car with an automatic transmission, 2 is the cylinder valve IJ, 3 is the cylinder head, 4 is the piston, 5 is the combustion chamber, 6 is the spark plug, 7 is the intake valve, 8 is the exhaust valve, 9 is the exhaust manifold 10
Oxygen sensor that detects oxygen i11 degrees in the exhaust gas, 15
16 is an ignition switch, and 21 is a battery power source.

In the intake system, an air flow meter 25 measures the intake air taken in from the air cleaner 24, and
The intake air temperature is measured by the intake air temperature sensor 26, and the intake air is supplied to the intake manifold 3 for a predetermined period of time by the throttle valve 28, which opens and closes depending on how far the accelerator pedal 27 is depressed.
It is designed to send to 0. The throttle body 31 is provided with a throttle sensor 32 that detects the opening degree and fully closed position δ of the throttle valve 28 disposed therein.

Additionally, an air bypass passage 34 is provided that bypasses the throttle body 31 and connects the intake pipe 33 and the surge tank 14. It is controlled mainly to control the idle speed.

In the fuel system, a fuel injection valve 38 is installed near the intake valve 7 to inject and supply a predetermined amount of fuel that is pumped from the fuel tank 35 by a fuel pump 37 through a passage 36.
The fuel pressure applied to the fuel injection valve 38 is adjusted by a pressure regulator 39. That is, during normal operation, the intake pipe negative pressure is introduced into the diaphragm chamber of the pressure regulator 39 by the pressure control valve (VSV) 45, and the fuel pressure applied to the fuel injection valve 38 is always kept at a predetermined value, for example, 2.55%, from the intake pipe pressure. ctA, and excess fuel is returned to the fuel tank 35 through a passage 46. Atmospheric pressure is introduced into the diaphragm chamber of the pressure regulator 39 by a pressure control valve (VSV) 45 during "high temperature start" operation, and the fuel pressure applied to the fuel injection valve 38 is increased regardless of the intake pipe pressure. .

The rotation speed of the fuel pump 37 is switched between two stages, a high speed side and a low speed side, by a pump rotation speed switching means incorporated in the control device 50, and when the potential applied to the fuel pump 37 is high, the fuel pump 37 is switched. It rotates at high speed and the fuel discharge flow rate is different.

In the ignition system, the high voltage generated by the ignition coil 40 is supplied to a distributor 41, and the high voltage is distributed and supplied to the spark plugs 6 of each cylinder at a predetermined timing while controlling the ignition timing in a predetermined manner. The distributor 41 is provided with a rotation speed sensor 43 that detects the rotation angle and rotation speed from the rotational position of a distributor shaft 42 that rotates in synchronization with a crankshaft (not shown). Accordingly, 24 pulse signals are output every two revolutions of the crankshaft 17, and one pulse signal is output at a predetermined angle every one revolution of the crankshaft.

The control device 50 is a microcomputer operated by the battery power source 21, and as shown in FIG. 3, the microcomputer includes a central processing unit 1q! , 1 nit (
A read-only memory (ROM>52), a random access memory (RAM) 53, and a backup random access memory (RAM) 54 that retains memory even when the ignition switch 16 is turned off.

Of these, the ROM 52 stores programs such as a main routine, a fuel injection amount control routine, an ignition timing control routine, and various fixed data and constants necessary for these processes. Furthermore, inside the microcomputer,
A/D converter 55 having a multiplexer and a buffer 7
An I10 device 56 having a memory is incorporated, and these 55 and 56 are connected to each other by a bus 57.

Depending on the A/D converter 55, an air flow meter 25,
The output signals of each sensor such as the intake air temperature sensor 26 are input to a multiplexer via a buffer, and these data are
D conversion and J, and CP at a predetermined time according to the command of the CPU 51.
It is configured to output to U51 and RAM53 or 554. As a result, the latest detected data such as intake air amount, intake air temperature, and water temperature are loaded into the RAM 53, and these data are stored in the predetermined area. Also, the I10 device 56 smell (
(Input the detection signals of each sensor such as the throttle sensor 32 and rotation speed sensor 43, and send these data to the CPU 5.)
CPU 51 and RAM 5 at a predetermined time according to the command of
3 or 54.

The CPU 51 calculates fuel injection 1 ffl based on the data detected by each sensor according to a program stored in the ROM 52, and outputs a pulse signal based on this to the fuel injection valve 38 via the I10 device 56. That is, basically, the basic fuel amount is calculated based on the intake air amount detected by the air flow meter 25 and the engine speed detected by the rotation speed (1) 43, and this is determined depending on the water temperature and intake air temperature. A pulse signal corresponding to the corrected fuel ω is sent to the fuel injection valve 38 from a drive circuit (not shown) in the I10 device 56.

The fuel injected from the fuel injection valve 38 is cut off when the opening/closing rotation speed exceeds a predetermined fuel cut rotation speed under predetermined operating conditions. The fuel cut rotation speed, which is a reference for stopping fuel injection, is, for example, the vehicle speed or less than a predetermined speed, and when the shift lever of the automatic transmission is shifted from the N range to the D range, the fuel cut rotation speed NGO, for example, 1
Temporarily set to 500 rpm. The shift lever position is detected by a sensor 60.

Next, a fuel cut speed/rotational speed calculation routine for executing a fuel cut will be explained based on FIG. 4. This routine is executed, for example, at regular time intervals or at regular crank rotation angles.

In the first step 101, the vehicle speed is AKI/hour! If the vehicle speed is less than Δtouch per hour, the process proceeds to step 102, where it is determined whether or not the shift lever of the automatic transmission is in the D range. If it is D range, step 103
Then, it is determined whether the shift lever has changed from the N range to the D range.

When the shift lever is holding the normal range D range, that is, when the shift lever is not shifted from the N range to the D range, the process proceeds from steps 103 to 104, and the fuel cut rotation @NC is larger than the overrun prevention rotation speed NCX. If it is determined that NC>Ncx, step 1
05, the fuel cut rotation speed NC is set to the overrun prevention rotation speed NCX, and this routine ends.

When the shift lever is switched from the N range to the D range, the process proceeds from step 103 to step 106, where the fuel cut rotation speed NC is set to an initial value [jNco, for example, 1500 rpm.
Set this to end this routine. As shown in Fig. 5, when switching from N range to D range when the vehicle speed is less than AKIR per hour, the fuel cut rotation speed NC is set to 6500, for example.
rpm to 15oorpm.

After the shift lever is switched from the N range to the D range, the process proceeds from step 103 to step 104, where it is determined whether the fuel cut rotation speed NC is greater than the overrun prevention rotation speed NCX, and if NC≦NCx. The process proceeds to step 107, where the fuel cutoff rotation speed NC is set to NcO+kXt. k is a constant, and t is the elapsed time after switching from the N range to the D range. As long as the condition of NC≦Ncx is satisfied in step 104, the value of the fuel cut rotation speed NC is incremented by k per unit hourly revolution.

In step 101 and step 102, the vehicle speed is set to AK per hour.
If it is determined that it is equal to or higher than IR or that the shift lever is in a range other than the D range, the fuel cut rotation speed NC is set to the overrun prevention rotation speed NCX in step 108, and this routine is ended.

In this way, when the vehicle speed is less than A/clII per hour and the shift lever is switched from the N range to the D range, the fuel cut rotation speed is changed from the overrun prevention rotation speed NCX to N
GO, and then gradually increase the value of fuel cut rotation aNC from the initial value NCO, so when switching from N range to D range while the engine speed is in the high speed range, as shown in Figure 5. As shown, the fuel cut state continues for a predetermined period of time, and during this fuel cut period, the engine speed NE rapidly decreases from the high speed range due to the load from the automatic transmission.
As a result, the torque applied to the automatic transmission etc. can be reduced and damage thereof can be reliably prevented.

In this example, since fuel injection is temporarily stopped due to fuel cut, the transition from the high speed rotation range to the idle rotation range occurs after 9 hours (compared to the case where the fuel injection rJ4.41k is reduced). The time is short, and when the accelerator pedal is depressed enough to shift from the N range to the D range, the rotation speed quickly exceeds 111111, and the car can be started smoothly according to the driver's intention.

First time with fuel cut speed! I(flNco) may be a function of the water temperature of the m function, and for example, the value may be set to a higher rotational speed as the water temperature becomes lower.

Further, the detection signal for the shift operation from the N range to the D range may be obtained directly from the shift lever position sensor, or may be a control signal to the &Ij control valve that is activated when switching from the N range to the D range, or a control signal related thereto. A signal may also be used. In addition, the fuel cut 114tl of the present invention
Of course, the D @ arrangement may be applied to diesel engines of automobiles equipped with automatic transmissions.

Fig. 5 shows the fuel cut rotation speed in another embodiment, and unlike the one shown in Fig. 4, the fuel cut rotation speed is determined by a timer for a predetermined time when the shift lever is shifted from the N range to the D range. is set to the initial value NCO, and then the fuel cut rotation speed is returned to the overrun prevention rotation speed NCX under predetermined operating conditions.

In the case of this embodiment as well, when the vehicle is stopped, the shift lever is set to the N range, the accelerator pedal is depressed to set the high speed range, and then the fuel is cut off for a predetermined period of time when the shift lever is switched from the N range to the D range. is executed, it is possible to prevent the torque applied to the automatic transmission from becoming excessive during this fuel cut period and prevent damage to the automatic transmission.

The predetermined timing for fuel cut is set to the time after the shift lever is switched from the N range to the D range, when the engine speed has sufficiently decreased from the high speed range to the medium to low speed range, and when the accelerator pedal is depressed and the vehicle is turned off. The time is set to be short enough not to interfere with starting the vehicle.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when the automatic transmission 1 is shifted from the stop range to the drive range, fuel cut is executed to rapidly reduce the engine speed even if the engine speed is high. Therefore, it is possible to prevent excessive torque from being transmitted to drive systems such as automatic transmissions, clutch devices, and differential gears.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a schematic diagram of an internal combustion engine and its peripheral equipment to which the present invention is applied, and Fig. 3 is a block diagram of the control device of Fig. 2. , FIG. 4 is a flowchart showing the fuel cut speed calculation routine in the embodiment of the present invention, FIG. 5 is a graph showing the relationship between the fuel cut speed and the engine speed, and FIG. 6 is a graph corresponding to FIG. 5 showing the fuel cut rotation speed in the example. 1... Internal combustion interlayer body, 6... Spark plug, 28
...Suttle valve, 38...Fuel injection valve, 50...Control i20 device,
51...Central processing unit (CPLI), 52...
Read only memory (ROM), 53... Random access memory (RAM), 54... Backup R
AM (backup RAM).

Claims (1)

[Scope of Claims] A fuel cut means that cuts fuel supplied to the engine when the engine speed exceeds a fuel cut speed, and a shift lever of an automatic transmission to which the engine output is transmitted changes from a stop range to a running range. a shift operation detection means for detecting a shift operation from a stop range to a driving range; and when the shift operation detection means detects a shift operation from a stop range to a driving range, the fuel cut rotation speed is set to a fuel cut rotation speed during normal operation. A fuel cut control device for an internal combustion engine, comprising: a fuel cut rotation speed reduction means for setting the rotation speed to a lower rotation speed than .