JPH05332201A - Start facilitation device of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide stable rest are ability without making air-mixture lean even if any slight leakage is generated as the worst case during a normal operation by supplying air to an internal combustion engine at the time of restarting at a high temperature, in a start facilitation device of the internal combustion engine which facilitates restartability at the time of stopping at a high temperature. CONSTITUTION:An air introduction port 17 and an air introduction valve 16 which opens/closes the air introduction port 17 are arranged slightly upstream from a carburetor 13. The air introduction valve 16 is opened when a negative pressure introduction port 16e is opened to the atmosphere. The negative pressure introduction port 16e is communicated with an air intake passage 12 by an electromagnetic valve 19 during operation of an internal combustion engine 11, and communicated with a temperature switching valve 21 during its stop. The temperature switching valve 21 is opened when the temperature of the internal combustion engine is set to a specified level or higher and the atmosphere is supplied to the electromagnetic valve 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine starting acceleration device, and more particularly to an internal combustion engine starting operation for promoting restartability of an internal combustion engine in which vaporized fuel is discharged from a carburetor into an intake passage when stopped at high temperature. Regarding a promotion device.

[0002]

2. Description of the Related Art Conventionally, as a start-up promoting device for an internal combustion engine that promotes restartability immediately after the internal combustion engine stops at a high temperature, by introducing fresh air directly into a downstream intake passage of a carburetor at the time of restarting, A device for correcting the air-fuel ratio of the air-fuel mixture sucked into the internal combustion engine at the time of high temperature restart to improve the restartability has been proposed (Shokai 58-183952).

FIG. 2 is a diagram showing the configuration of the above conventional device. In the figure, reference numeral 1 denotes an internal combustion engine, which is connected to a carburetor 3 and an air cleaner 2 via an intake passage 4. When an intake negative pressure is generated in the intake passage 4, the air sucked from the air cleaner 2 is supplied to the carburetor 3. In the vaporizer 3, the fuel supplied from a fuel tank (not shown) is vaporized by the flow of the air. Therefore, the characteristics of the carburetor 3 determine the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 1.

A solenoid valve 5 is connected to the intake passage 4 via a bypass passage 6. The solenoid valve 5 opens or shuts off the bypass passage 6 from the atmosphere by switching the selector switch 7. Therefore, in the internal combustion engine 1, only air that does not contain fuel can be supplied from the bypass passage 6 to the intake passage 4.

On the other hand, when the internal combustion engine 1 stops at high temperature,
The vaporized fuel generated in the vaporizer is discharged from the vaporizer 3 into the intake passage 4, and the vaporized fuel is filled from the intake passage 4 into the air cleaner 2. Therefore, if the internal combustion engine 1 is restarted in this state, the air-fuel mixture supplied to the internal combustion engine 1 becomes rich and the startability deteriorates.

As described above, the internal combustion engine 1 can supply the fuel-free air through the bypass passage 6, and the air is supplied when the internal combustion engine 1 is restarted at a high temperature. Therefore, when the internal combustion engine 1 is stopped at a high temperature and the restartability is deteriorated due to the evaporated fuel, air containing no fuel is supplied to the intake passage 4. Therefore,
The internal combustion engine 1 is supplied with the fuel gas whose air-fuel ratio has been corrected, and good restartability is obtained.

[0007]

However, in the above-mentioned conventional device, the bypass passage 6 is shut off and opened by the solenoid valve 5, and the bypass passage 6 directly communicates with the intake passage 4 downstream of the carburetor 3. ing. For this reason, the negative pressure applied to the solenoid valve 5 becomes large at the time of idling of the internal combustion engine in which the amount of air flowing in the carburetor 3 is small.

Therefore, in the above conventional device, the solenoid valve 5
It is necessary to use an expensive one having excellent durability, and if an abnormality occurs in the solenoid valve 5 and a leak occurs, the air-fuel ratio during normal operation of the internal combustion engine 1 becomes lean. In particular, when idling, a negative pressure is applied to the solenoid valve 5 and air due to leakage increases, so that the air-fuel ratio becomes leaner, causing rough idle.

The present invention has been made in view of the above points, and prevents the air-fuel ratio from becoming rich by introducing outside air at the time of restarting from high temperature to normal temperature, and leakage occurs during normal operation. Even if the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine does not become lean, it is an object of the present invention to provide a starting promotion device for an internal combustion engine that ensures stable drivability.

[0010]

SUMMARY OF THE INVENTION The above-mentioned problems are, in an internal combustion engine start-up promoting device for improving restartability at high temperature of an internal combustion engine in which fuel is supplied by a carburetor, upstream of the carburetor in an intake passage. And an external air introduction unit that is provided in the vicinity thereof and that introduces external air into the intake passage, and a control unit that controls the external air to be introduced into the external air introduction unit for a predetermined time when the internal combustion engine is started at a predetermined temperature or higher. It is solved by providing and.

[0011]

According to the above construction, when the internal combustion engine is restarted at a high temperature, the control means causes the outside air introducing means to introduce the outside air for a predetermined time. The outside air introduced from the outside air introduction means is supplied to the carburetor together with the gas filling the intake passage.

Therefore, even when the intake passage is filled with the evaporated fuel, the evaporated fuel is supplied to the carburetor as a gas diluted with the outside air, so that the air-fuel ratio does not become rich. ..

Further, when the temperature of the internal combustion engine has not reached a predetermined temperature, or when the internal combustion engine has started a normal operation and a predetermined time has elapsed, at the time of starting, a slight amount of evaporated fuel is added to promote startability. Therefore, the air supply means does not introduce outside air. Even if the valve leaks during operation, there is no influence on the air-fuel ratio (fluctuation) of the air-fuel mixture supplied to the internal combustion engine after the carburetor, and there is no lean deviation.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of an embodiment of a start promoting apparatus for an internal combustion engine according to the present invention. A carburetor 13 is connected to the internal combustion engine 11 via an intake passage 12. The vaporizer 13 has a large venturi 13a, a small venturi 13b, and a float chamber 13c therein.

Fuel supplied from a fuel tank (not shown) is stored in the float chamber 13c, and when negative pressure is generated in the small venturi 13b, the fuel is sucked out and supplied to the internal combustion engine 11. Most of the fuel is supplied from an idle port (not shown) during idling operation.
Further, since the atmospheric pressure in the float chamber 13c is released to the atmosphere, the space above the fuel in the float chamber 13c and the upstream of the small venturi 13b are communicated with each other by the inner vent 13d.
Is provided.

Therefore, when the internal combustion engine 11 is started and an intake negative pressure is generated in the intake passage 12, an air flow is generated in the carburetor 13, and the fuel in the float chamber 13c is discharged from between the small venturis 13b. Also, most fuel is idle port or slow port (not shown) during idling operation.
Sucked out from. After that, it is mixed with air in the carburetor 13 and supplied to the internal combustion engine 11 through the intake passage 12.

An air cleaner 15 is connected to the carburetor 13 via an intake passage 14, and the air passing through the air cleaner 15 is supplied to the carburetor 13 in a normal state. Further, an air introduction valve 16 and an air introduction hole 17 corresponding to outside air introduction means are provided at a position near the carburetor 13 on the side of the intake passage 14.

The air introducing valve 16 includes a diaphragm 16b inside a main body 16a and a diaphragm 16b.
It has a spring 16c that urges it toward the intake passage 14. Further, the diaphragm 16b partitions the inside of the main body 16a into two spaces, and when negative pressure is supplied from the negative pressure inlet 16e, the diaphragm 16b separates from the intake passage 14 against the tension of the spring 16c. Move in the direction.

On the other hand, the intake passage 14 of the diaphragm 16b
A valve body 16d is attached to the side through a drive shaft.
This valve body 16d is provided with an opening 14a on the side wall of the intake passage 14.
The diaphragm 16b is a valve that opens and closes the spring 1
When being urged toward the intake passage 14 by 6c,
The opening 14a is opened. Further, when the diaphragm 16b is moving in the direction opposite to the outside air passage 14 due to the negative pressure introduced from the negative pressure introducing port 16e, the opening 14a is closed.

An air inlet 17 is provided in the opening 14a of the intake passage 14, and when the valve body 16d is open,
The air that has passed through the air introduction port 17 is introduced into the intake passage 14. This air is cleaned by a filter 17 a provided inside the air introduction port 17 and introduced into the intake passage 14. Further, the opening 14a is provided in the vaporizer 13.
Since the valve body 16d is located slightly upstream of, the air that has passed through the opening 14a is supplied to the carburetor 13 when the valve body 16d is open.

The negative pressure inlet 16e communicates with a solenoid valve 19 via a delay valve 18. This solenoid valve 19 connects either the negative pressure inlet 16e and the check valve 20 or the negative pressure inlet 16e and the temperature switching valve 21 by switching the selector switch 22. In the apparatus of this embodiment, the delay valve 18, the electromagnetic valve 19, the check valve 20, the temperature changeover valve 21, and the changeover switch 22 constitute the control means of the outside air introducing means.

In this embodiment, the changeover switch 22
Is interlocked with an ignition switch that indicates the operating state of the internal combustion engine 11, and when the internal combustion engine is operating (the ignition switch is on), the negative pressure inlet 16e and the check valve 20 are in conduction and are stopped (ignition). When the switch is off), the negative pressure inlet 16e and the temperature switching valve 21 are electrically connected.

The check valve 20 is a one-way valve that allows only the flow from the solenoid valve 19 to the intake passage 12 to pass therethrough. When a negative intake pressure is generated in the intake passage 12, the check valve 20 is opened to release the negative pressure. Tell 19.

On the other hand, the temperature switching valve 21 is arranged near the intake passage 12, and opens when the detected temperature is higher than a predetermined temperature to open the solenoid valve 19 to the atmosphere, and when the detected temperature is lower than the predetermined temperature. It is a temperature-sensitive solenoid valve that is closed to shut off the solenoid valve 19 from the atmosphere.

Therefore, when the internal combustion engine 11 is operating, the solenoid valve 19 connects the intake passage 12 and the negative pressure introducing port 16e via the check valve 20. Therefore, the air introduction valve 16
The intake negative pressure is supplied to the valve body 16d so that the valve body 16d closes the opening 14a, so that air is not introduced from the air introduction port 17.

When the operation of the internal combustion engine is stopped before the internal combustion engine is sufficiently warmed up (the ignition switch is turned off), the solenoid valve 19 is switched and the negative pressure introducing port 16e and the temperature switching valve 21 are electrically connected. On the other hand, when the internal combustion engine 11 is not sufficiently warmed up, the fuel in the fuel tank and the carburetor is not heated and the amount evaporated from the float chamber 13c is small. Therefore, the evaporated fuel discharged from the inner vent 13d is
The restartability of the internal combustion engine 11 is not deteriorated by filling the intake passage 12, and the restart can be performed only by the air that has passed through the air cleaner 15 as usual.

Therefore, in the device of the present embodiment, when the temperature in the vicinity of the intake passage 12 is lower than the predetermined temperature, the temperature switching valve 21 is closed and stored in the air introducing valve 16 and the delay valve 18. The negative pressure is maintained and the valve body 16d is closed.

Then, in order to restart the internal combustion engine 11 from this state, when the ignition switch is turned on,
The electromagnetic valve 19 is switched again, and the intake passage 12 and the negative pressure introducing port 16e are electrically connected. At this time, immediately after the ignition switch is turned on, the intake negative pressure is not generated in the intake passage 12, but the negative pressure stored in the air introduction valve 16 and the delay valve 18 is caused by the action of the check valve 20. Is maintained and the valve element 16d does not open.

When the internal combustion engine 11 is sufficiently warmed up and then stopped (the ignition switch is turned off), the fuel is evaporated by the residual heat of the internal combustion engine 11. This evaporated fuel is used in the vaporizer 1.
Is discharged from the inner vent 13d of No. 3 into the vaporizer 13,
The intake passage 12 and the air passage 14 are filled. This evaporated fuel causes deterioration of ignitability of a spark plug (not shown) and deterioration of combustibility due to a rich mixture at restart.

As described above, in the apparatus of this embodiment, when the ignition switch is turned off, the temperature switching valve 21 and the negative pressure inlet 16e are electrically connected. Further, since the internal combustion engine 11 has been sufficiently warmed up this time, the temperature in the vicinity of the intake passage exceeds a predetermined value, and the temperature switching valve 21 opens. Therefore, the air introducing valve 16 and the delay valve 18 are opened to the atmosphere, the valve body 16d is opened, and the air introducing port 17 is opened.
Air can be introduced from here.

When the internal combustion engine 11 is restarted in this state,
Solenoid valve 1 when the ignition switch is turned on
9 is switched, and the air introduction valve 16 is electrically connected to the intake passage 12 via the delay valve 18 and the check valve 20. Therefore, during the cranking, the air introduced from the air introduction port 17 is supplied to the carburetor 13, so that the fuel gas supplied to the internal combustion engine 11 is higher than that in the case of the cranking with the air containing the evaporated fuel. Has a low air-fuel ratio. Therefore, good restartability can be obtained even though the intake system is filled with the evaporated fuel.

On the other hand, when the ignition switch is turned on to crank the internal combustion engine 11, the solenoid valve 19 is switched and the air introduction valve 16 is electrically connected to the intake passage 12 via the delay valve 18 and the check valve 20. Therefore, when the cranking of the internal combustion engine 11 is completed and a stable negative pressure is generated in the intake passage 12, the negative pressure is transmitted to the delay valve 18 via the check valve 20, and the air introduction valve is gradually added. 16 are supplied.

Therefore, a desired negative pressure is supplied to the air introduction valve 16 within a predetermined time after the internal combustion engine 11 is started, the valve body 16d is closed, and thereafter the air introduction port 17 is opened to the outside air passage 1
No air is introduced into 4.

As described above, according to the apparatus of this embodiment, when the internal combustion engine 11 is stopped at a high temperature, even if the fuel in the float chamber 13c evaporates due to residual heat and fills the intake passage, it is restarted. Since the outside air is introduced from the air introduction port 17 into the intake passage 14 upstream and in the vicinity of the carburetor 13, good startability of the internal combustion engine 11 can be obtained.

The air introduction valve 16 is operated for a predetermined time after the start.
Is opened and the introduction of the outside air continues, so that the air-fuel mixture filled in the intake passage 14 is gradually supplied to the carburetor 13 together with the outside air and consumed. Therefore, the air-fuel mixture supplied to the internal combustion engine 11 does not suddenly become rich, and therefore, incomplete combustion gas is not exhausted from the internal combustion engine 11, and at the same time, stable initial operation can be obtained. it can.

Further, as described above, since the driving force of the valve body 16d is the negative pressure of the internal combustion engine 11, the opening and closing of the valve body 16d can be controlled with a stable and strong force, and high reliability can be obtained. You can

Further, in the apparatus of this embodiment, the air introduction port 1
Since 7 is arranged upstream of the vaporizer 13, the valve body 1
Even if an abnormality occurs in 6d and a leak occurs, it does not affect the operating state of the internal combustion engine 11. On the contrary, even if the valve element 16d leaks in the steady state, the internal combustion engine 11 is not affected so much, so that it is not necessary to make the valve element 16d and the like with high accuracy, and the valve element 16d can be implemented at low cost.

[0038]

As described above, according to the present invention, since the outside air introducing means is provided upstream of the carburetor, even if an abnormality occurs in the outside air introducing means and a leak occurs, it is supplied to the internal combustion engine. There is no influence on the air-fuel ratio of the supplied fuel gas, and the supplied fuel gas does not become lean as in the conventional case. Therefore, the reliability is higher than that of the conventional device, and it is not necessary to make the external air introducing means with high accuracy as in the conventional device.

As described above, the internal combustion engine startup promoting apparatus according to the present invention has the features of stable restartability at high temperature, low cost implementation, and high reliability. is doing.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a startup promoting device for an internal combustion engine according to the present invention.

FIG. 2 is a configuration diagram of an embodiment of a conventional startup promoting device for an internal combustion engine.

[Explanation of symbols]

 11 internal combustion engine 12, 14 intake passage 13 carburetor 16 air introduction valve 16a main body 16b diaphragm 16c spring 16d valve body 16e, 20 check valve 17 air introduction port 17a filter 18 delay valve 19 solenoid valve 21 temperature switching valve 22 changeover switch

Claims (1)

[Claims] 1. A start promoting device for an internal combustion engine, which improves restartability at high temperature of an internal combustion engine supplied with fuel by a carburetor, the intake passage being provided upstream and in the vicinity of the carburetor.
An external air introducing unit for introducing external air into the intake passage; and a control unit for controlling the external air to be introduced into the external air introducing unit for a predetermined time when the internal combustion engine is started at a predetermined temperature or higher. For promoting start of internal combustion engine.