JPS5851253A - Air-fuel ratio control system upon deceleration - Google Patents

Abstract

PURPOSE:To enable to correct the abnormal condition of the air-fuel ratio immediately by a method wherein a necessary amount of fuel is supplied into a suction system additionally by an accelerating pump provided on a carburettor in case a transmitting condition between an engine and wheels is cut upon deceleration. CONSTITUTION:When a vehicle is decelerated by means of engine brake upon the decelerating condition, the vacuum of a suction pipe is shifted to a high- vacuum side and a second switch 22 for an actuator control unit 15 is put ON. When a clutch is disconnected or a shift lever is located into a neutral position under this condition, the first switch 21 of said control means 15 is also put ON and a VSV (electric vacuum switching valve) is opened. Whereby, atmosphere in a tank 17 is introduced into the vacuum chamber 11c of a dash pot 11 through an introducing tube 18 and an operating rod 11a is descended by the energizing force of a spring 11d. As a result, a link 8 is descended to pivot a lever 7 into the direction of an arrow sign X and the accelerating pump 6 is energized to supply additionally the fuel 5 in a pump chamber 6b into the air suction path 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an air-fuel ratio control device during deceleration, which is capable of correcting inconveniences caused by an abnormal air-fuel ratio state during vehicle deceleration by using an acceleration pump of a carburetor. It is related to.

Recently, in automobiles that have been equipped with exhaust gas purification measures using catalysts, in order to prevent the inconvenience that a large amount of unburned gas is led to the exhaust system path during deceleration and burns on the catalyst bed, causing catalyst heating. In many cases, a fuel tank or a fuel pump is inserted into the slow system passage of the carburetor to limit the amount of fuel supplied from the slow system passage to zero or a very small value during deceleration.

However, if the fuel is cut and the deceleration state continues for a long time, all the fuel in the slow system passage will be sucked out, and the inside of the narrow boat and intake manifold will become dry and the air-fuel ratio will show an abnormally high value. The engine misfires. However, if the power transmission between the engine and the wheels is cut off in order to change gears or stop the vehicle, the rotational force applied to the engine from the wheels suddenly disappears, causing the engine to burn normally. This tends to cause the inconvenience of stopping without being able to return to the original state.

The present invention was made with attention to such circumstances, and
By making it possible to additionally supply the required amount of fuel into the intake system by using the acceleration pump installed in the carburetor when the transmission state between the engine and the wheels is cut off during deceleration. The present invention provides an air-fuel ratio control device during deceleration that can eliminate the above-mentioned disadvantages.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is the intake system path of the engine installed in a car, and 2
Fi is a carburetor inserted in the middle of this intake system path 1. The electrifier 2 is a normal one having a fuel supply system such as a slow system passage, a high speed system passage, or an acceleration system passage 3, but in the drawing, only the acceleration system passage 3 is shown and other passages are omitted. It is. The acceleration system passage 3 is for guiding the fuel 5 in the float chamber 4 into the intake system passage 1 via the acceleration pump 6. The acceleration pump 6 is, for example, a piston pump type in which the tip of a piston rod 6a is pivotally connected to a Leno (-7) that rotates in response to a sudden acceleration operation of the accelerator pedal (not shown). Accordingly, when the lever 7 rapidly rotates in the direction of the arrow X, the fuel 5 in the pump chamber 6b is additionally supplied into the intake system path 1. The upper end of the link 8 is connected to the extending portion 7a via a nupling 9, and the lower end bent portion 8a of the link 8 is connected to the extending portion 7a by an actuator, for example, the operating rod 11a of the dash board 1-11. By pressing downward, the lever 7 can be rotated in the direction of arrow X.

That is, this dashboard 11 is for operating the acceleration pump 6 separately from the accelerator pedal ν, and a vacuum chamber 110 formed on the back side of the diaphragm llb that supports the operating rod 11a has a negative The slot/revalve 13 of the suction thread passage 1 is also communicated with the downstream part through the pressure introduction pipe 12, and a check valve and an orifice are provided in parallel in the middle of the negative pressure introduction pipe 12. A VTV (negative pressure delay valve) 14 is inserted. The dashpot 11 is actuated by the actuator control means 15 in a direction to energize the acceleration pump 6. The actuator control means 15 has an air tank 17 that opens to the outside world through an orifice 16, and an atmospheric pressure introduction pipe 18 that communicates the inside of this air tank 17 with the vacuum chamber 11G of the dash board 11. In the middle of this atmospheric pressure introduction pipe 18, there is a VS for opening and closing the atmospheric pressure introduction pipe 18.
A V (electric negative pressure switching valve) 19 is inserted. VS
VI9 is an electromagnetic opening/closing valve whose input terminal 19aJc is in an open state when energized) and is in a closed state when energized, and its input terminal 19a is connected to the first switch 21 and the second switch. 22 in series with battery 2.
Connected to 3. The first switch 21 is turned on when the power transmission state between the engine and the wheels is cut off, for example, when the clutch is disengaged or when the shift lever is positioned at 221 tral. It is configured to be in the OFF state in other cases. The second switch 22 is activated when the vehicle is in a decelerating state, for example, when the intake pipe negative pressure changes to the vacuum side of 580 ff1M Hg, or when the engine speed and intake pipe negative pressure change. 1cON when the combination reaches a value indicating a deceleration state, etc.
It is configured to be in the OFF state in other cases. Incidentally, reference numeral 24 is an arm for opening the throttle valve slightly in accordance with the protruding operation of the actuating rod 11a of the dash pot 11.

Next, the operation of this device will be explained. Under normal operating conditions, at least one switch 21, 22 of the actuator control means 15 is in the OFF' state, so the VSV
19 is maintained in a closed state, and the atmospheric pressure introduction pipe 18 is cut off. Therefore, the intake pipe negative pressure is introduced into the vacuum chamber 110 of the dashpot 11 through the negative pressure introduction pipe 12, and the operating rod 11a of the dashpot 11 is held in the retracted position. On the other hand, when the accelerator pedal is released and the vehicle is decelerated by engine braking, the second switch 22 of the actuator control means 15 prevents the intake pipe negative pressure from moving toward the high vacuum side.
is maintained in the ON state. From this state, when the clutch is disengaged or the shift lever is placed in neutral in order to stop the vehicle that has undergone a gear change, the first switch 21 of the actuator control means 5 is also switched to the ON state. VS' of the control means 15
V19 becomes open.

Therefore, the atmosphere stored in the air tank 17 is instantaneously led into the vacuum chamber 11c of the dashbot 11 through the atmospheric pressure introduction pipe 18, and the actuation rod 11a of the dashbot 11 is It protrudes downward due to the biasing force. As a result, the link 8 is pushed downward, and the lever 7 is rapidly rotated in the direction of arrow X, thereby energizing the acceleration pump 6. In other words, the acceleration pump 6 receives the same urging force as when the accelerator pedal is suddenly accelerated N, and the fuel 5 in the bong housing 6b is additionally supplied into the intake pipe 1. From this state, when the clutch is engaged or the shift lever is placed in a state other than neutral, the VSV 19 is closed and the introduction of atmospheric air is stopped, and the dashbot 11
The atmosphere that has entered the vacuum house IC has a delay effect V
Since the J/C in the intake system path 1 is sucked out through the TV 14 after a certain time delay i1 (with a time delay long enough to stabilize combustion), the operating rod 11a of the dashbot 11 sinks upward and returns to its original state. Return to state.

In this way, according to this device, if the 171 J power transmission state between the engine and the wheels is cut off during deceleration, the acceleration pump 6 operates to instantly correct the air-fuel ratio abnormality during deceleration. Therefore, the engine can be immediately returned to the normal latent combustion state from the misfire state. Therefore, for example, when changing gears from applying engine braking in 3rd gear to moving to 4th gear, or when stopping the vehicle after deceleration, there are cases where the latch is turned off. This can effectively eliminate inconveniences such as the engine stopping as it is in some cases. Moreover, since this device effectively utilizes the acceleration pump 6 of the electrifier 2 to achieve the above-mentioned effect, there is no need to provide a special fuel supply pump, etc., and the configuration is simple and easy to implement. It is.

Note that the configurations of the actuator and the actuator control means are of course not limited to those described above. Various modifications can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

The drawing is a circuit explanatory diagram showing one embodiment of the present invention. 1----- One intake system path, 5, ----- One combustion version, 6--
----Acceleration pump, 1l---Actuator (
dashbot) 15--actuator control means. −tsu −

Claims (1)

[Claims] An accelerator pump that additionally supplies the required amount of fuel into the intake system when the accelerator pedal is suddenly accelerated, an actuator that operates the accelerator pump separately from the accelerator pedal, and a signal that indicates a deceleration state. A signal indicating the presence or absence of power transmission from the engine to the wheels is used as input information to direct the actuator to energize the acceleration pump only when it is detected that the transmission state between the engine and the wheels is cut off during deceleration. 1. An air-fuel ratio control device during deceleration, comprising: an actuator control means for operating the air-fuel ratio during deceleration.