JPH0151894B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deceleration control device for an internal combustion engine, and more particularly to a deceleration control device suitable in terms of fuel efficiency, drivability, and emissions.

In recent years, as fuel regulations have been tightened along with exhaust regulations, efforts have been made to make the air-fuel ratio leaner during startup and warm-up, and to make fuel more economical during acceleration and deceleration.
Among these, fuel cutting during deceleration is known to be particularly effective in improving fuel efficiency.

However, conventional deceleration control places too much emphasis on fuel efficiency, which leads to a worsening of the feeling during deceleration, and because of the reduced controllability of fuel recovery, the engine stalls when the clutch engages after shifting, and smooth idling is not ensured. (Refer to Japanese Patent Laid-Open No. 55-49537).

SUMMARY OF THE INVENTION An object of the present invention is to provide a deceleration control device for an internal combustion engine that is excellent in fuel efficiency, drivability, and emission.

In order to achieve such an objective, the present invention
An injector is installed in the intake passage, and the amount of fuel injected from the injector is determined depending on the engine condition.
In the device that controls Gf, the first means detects the deceleration state of the engine, the second means determines the engine speed, and when the first means detects the deceleration state, the amount of fuel injected from the injector is set to K _DEC ×
Gf, and by the second means, if N _e ≧N _up , then K _EEC =
0, N _up > N _e > N _LW , K _DEC > 1, N _e ≦N _LW
and a third means for setting K _DEC =1.

Hereinafter, the present invention will be explained in detail using Examples.

FIG. 1 is a sectional view showing one embodiment of an intake passage in which an injector is disposed. In the figure, it is called an upstream single point injection device 1, and a throttle valve 5
An injector 6 is disposed upstream of the injector 6, and the amount of intake air is determined by detecting the amount of air flowing through the bypass air passage using the hot wire sensor 4.
The voltage is converted into a voltage and input to a control circuit (not shown). The control circuit determines the injection period and injection pulse width of the injector 6 based on the signal from the hot wire sensor and the signal corresponding to the engine speed Ne, and injects fuel from the injector 6 based on the output signal to empty the injector. The fuel ratio is controlled to a target value. On the other hand, the throttle valve 5 is provided with an idle switch (not shown) that turns on and off depending on its opening degree, and when this idle switch is on, it can be determined that the throttle valve is in a deceleration state. . Note that whether or not deceleration is in progress is determined not only by the idle switch, but also by checking whether the throttle opener is operating or not, and whether the contact switch in the throttle actuator is ON, as shown in Figure 2. The determination can also be made based on whether or not the air valve is operating, whether or not the air valve is operating, and whether or not the intake pressure P _n satisfies P _n ≦P _set . Therefore, when the deceleration state is determined by the above-described mechanism, the engine rotation speed N _e is detected next. Here the engine speed
When N _e is N _e ≧ N _up , the injected fuel cost (K _DEC × G _f ) from injector 6 is increased to improve fuel efficiency.
By setting K _DEC = 0, fuel is cut off. Furthermore, in the case of N _LW <N _e <N _up , deceleration correction is performed to ensure drivability and improve emission. Fig. 3 is a graph showing a method for performing deceleration correction, and as shown in Fig. 3a, when atmospheric pressure P _n is P _n ≦ P _set , it is defined as a deceleration region;
Regarding the engine speed N _e , as shown in Figure 3b, N _LW < N _e < N _up , K _DEC is set to 1 or more to make the air-fuel ratio rich, and in order to prevent extreme enrichment and dilution, K _DEC is set to change continuously. Also, for atmospheric pressure P _n , Fig. 3 c
As shown in FIG. 3, when P _n > P _set , K _DEC = 1, and when P _n ≦ P _set , K _DEC ≧ 1, so that it changes continuously as in Fig. 3b. If none of the deceleration determination conditions is satisfied, map control and feedback control based on the hot wire sensor 4 and the engine speed are performed when N _e <N _LW .

In this way, fuel cut and enrichment can be controlled accurately by determining deceleration and engine speed, so that fuel efficiency, drivability, and emissions can be satisfied at the same time.

In particular, since N _up > N _e > N _LW is controlled based on engine speed, accurate control is possible regardless of various operating conditions, and NOx and CO emissions are minimized. can do.

Further, when N _e ≦N _LW , discharge of unburned gas can be prevented, and control can be performed in conjunction with the control when N _up >N _e >N _LW .

In the above-mentioned embodiment, an upstream single point injection device is described in which an injector is disposed upstream of a throttle valve as an intake passage, but the invention is not necessarily limited to this, and as shown in FIG. Needless to say, the present invention can also be applied to a downstream single point injection device by disposing an injector 6 downstream of the throttle valve 5.

As is clear from the above description, the deceleration control device for an internal combustion engine according to the present invention can provide excellent fuel efficiency, drivability, and emissions.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of an intake passage in which an injector is arranged, FIG. 2 is an explanatory diagram showing an operation flow of an embodiment of the deceleration control device for an internal combustion engine according to the present invention, and FIGS. b and c are detailed explanatory views when operating according to the above-mentioned operation flow, and FIG. 4 is a sectional view showing another embodiment of an intake passage in which an injector is disposed. 1... Upstream single point injection device, 3... Air flow meter, 4... Hot wire sensor, 5... Throttle valve,
6...Injector.

Claims (1)

[Claims] 1 An injector is disposed in an intake passage and the amount of fuel G _f injected from the injector is controlled according to the engine condition, which includes a first means for detecting a deceleration state of the engine and a first means for determining the engine rotation speed. K _DEC the amount of fuel injected from the injector when the deceleration state is detected by the second means and the first means.
×G _f , and by the second means, if N _e ≧N _up , then K _DEC
=0, when N _up > N _e > N _LW , K _DEC >1; and when N _e ≦N _LW , K _DEC = 1.