JPS5832952A - Carburetter equipped with float chamber with air introduction switch valve - Google Patents

Abstract

PURPOSE:To restrain bubbling in a float chamber by connecting an air-introduction passage to the upper space of the float chamber via a switch valve. CONSTITUTION:An air-introduction pipe 15 is fixed to keep an outlet near a fuel-introduction needle valve, while a switch valve 10 is fast fixed at the top of this pipe 15. The switch valve 10 is connected to the outside via a filter 11, and controlled by a thermal switch 18 and a car-speed switch 17. During the operation of an engine, the air brought in through the filter 11 is introduced into a float chamber 1 via the air-introduction pipe 15. In this construction, since the air of low temperature is brought in contact with the surface of fuel oil, bubbling of fuel gas is restrained. When the engine is stopped, since current is not given to a coil 14, a valve 12 is closed by the elastic force of a spring 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carburetor for a gasoline engine, and particularly to a carburetor having a 70-tooth chamber with an air introduction switching valve.

The 70-tonne in the carburetor is heated by the MK in the engine room, making it easy for bubbles to form, but recently there has been a trend to use gasoline with a large amount of volatile components to make starting smooth in cold weather. 6ru. Especially in the United States, this rounding is 12 to 15 Ab/! The problem is that gasoline with a high vapor pressure and a large amount of y components causes a storm (because gasoline is used for each use, the gasoline boils during warming and sends a large amount of fuel vapor), causing a lack of acceleration during engine stall. is occurring.

In order to prevent this phenomenon, it is conceivable to surround the 7-fourth chamber with a heat insulating material to suppress the rise in fuel temperature, but it is extremely difficult to insulate it to achieve this effect. i9. An inner vent pipe and a passage to the canister are provided to allow dripping between the upper space of the 70-F wealth and the downstream of the air cleaner t. During operation, evaporated fuel is sent to the inch vent pipe and combusted by the engine. When the engine is stopped, the inch vent pipe is closed and the passage to the 4-Yanister is closed, allowing vaporized fuel to be adsorbed into the canister.

However, when operating at relatively low speeds, the amount of fuel consumed in the float chamber is small, so the temperature of the fuel in the float chamber rises, evaporation becomes active, and a large amount of vaporized fuel is sent to the engine from the inner vent pipe. The air-fuel mixture becomes richer.Although fuel gas is adsorbed in the canister, it is also released and supplied to the engine, so the warm air-fuel mixture becomes richer, making engine operation unsmooth and deteriorating the exhaust gas composition. This caused the problem of having to do so. In addition, when the generation of fuel bubbles is severe, the bubbles enter the main nozzle through the main nozzle, causing the amount of main fuel supplied from the nozzle to be intermittently varied.

The present invention provides an air introduction switching valve seal 7E that can suppress the generation of bubbles in the fuel in the float chamber to ensure smooth operation.
l-) one objective is to provide a vaporizer with a wealth of
The feature is that an air introduction passage is further connected to the upper space of the flow) IIO, and a switching valve is installed in this air introduction passage, and under predetermined operating conditions, the switching valve is opened to introduce air. However, under other operating conditions or when the engine is stopped, the switching valve shall be configured to close.
be.

FIG. 1 is a sectional view of an air exchange section having a float chamber with an air introduction switching valve, which is an embodiment of the present invention.

On the right side of the carburetor, there is a port chamber 1 which stores a certain amount of fuel 2), and at the bottom of this 7-pocket chamber 1, it is connected to the main jet 4 through a round hole 3. It's communicating. When air flows into the bench area 8 and negative pressure is generated in the main nozzle 7, the fuel sucked into the main jet 4 and the shift-in well 6 mixes with the air sucked in through the air pulley 6, and the mixture flows through the main nozzle 7. ] To gush.

In the upper space of the float chamber 1, an inner vent pipe 9 opens on the upstream side of the bench area, and a communication path to a canister (not shown) is also provided. The communication path between the inner vent pipe 9 and the canister is structured so that when either one is open, the other is closed.)
During operation, the inner vent pipe 9 opens and sends the evaporated fuel in the float chamber to the engine. When the operation is stopped, the communication path to the canister is opened to adsorb evaporated fuel and prevent fuel gas O from being released to the outside world. There is.

The steps up to this point are the same as the conventional ones, but in this embodiment, an air introduction pipe 15 having an outlet is attached near the needle pulp for fuel introduction, and a switching valve 10 is fixed to the tip of this air introduction pipe 15. There is.

The switching valve 10 communicates with the outside world through a filter 11, and the valve 12 facing the communication hole with the outside world is connected to the plunger 1.
3, and the plunger 13 is surrounded by a coil 14. That is, the switching valve 10 is made of solenoid pulp, and its coil is connected to a power source via a temperature switch 18 and a vehicle speed switch 17.

The operation of the vaporizer configured in this way will be explained next. 7
a-) The inventors have confirmed that the fuel bubbles generated in the float float 1 are significantly reduced when a small amount of outside air is introduced into the float float 1 and heated so as to blow onto the oil surface. The switching valve 10 allows such air to be obtained in a timely manner.

The rotation of the engine is 7. Since the inside of the stomach chamber 1 is in a small negative pressure state, the valve 12 must be sucked into the gas chamber 14 so as to open the O communication hole with the outside world where the filter 11 is attached. The objective will be achieved.

In other words, while the machine y is operating, the filter 11! Through the air introduction pipe 15, the introduced air is introduced into the 7-ml. As a result, fresh, low-temperature O air comes into contact with the fuel oil surface, so the generation of fuel gas bubbles is suppressed, and the amount of fuel supplied to the engine through the inner vent pipe 9 is reduced. That is, the air introduced through the switching valve 10 cools the oil level, and the inner vent pipe 9 acts to dilute the air-fuel mixture supplied to the engine.

On the other hand, when the engine is stopped and the current flowing through the switching valve Zoo:ff oil 14 is removed, the pulp 12 is closed by the spring force of the spring 16. Therefore, the fuel gas in the 74-ton 1 is deposited in the canister K1 without being released to the outside world. It should be noted that if the outlet of the air introduction pipe 1sO1 is provided near the needle pulp, which has the function of introducing fuel and storing a certain amount of fuel, it is highly effective in preventing the generation of fuel bubbles. Note that the air introduction pipe 15 is made of a rubber tube, and its heat insulating properties prevent the temperature of the air passing through the pipe from rising.

In general, engine drivability deteriorates due to the generation of fuel bubbles.
It tends to occur when specific conditions such as fuel temperature, vehicle speed, etc. are met, and therefore only when those conditions are met.
) It is better in terms of operability and reliability to open the chamber 1 to the outside world via the switching valve 1G, and not to open the rest to the atmosphere as in conventional carburetors, but to have a structure with only the inner vent pipe 9. It is.

In this embodiment, the switching valve 1G is equipped with a temperature switch 18 that detects the fuel temperature and operates according to the signal, and a vehicle speed switch 17 that can be controlled according to the vehicle speed.
Temperature and vehicle speed conditions are added to the functions. Of course, the fuel temperature can be substituted by the ambient temperature, oil temperature, and cooling water temperature of the engine, and the vehicle speed can be substituted by the engine rotational speed and lk input negative pressure. The temperature switch 18 can be opened when the fuel temperature is low and little fuel vapor is generated, and the vehicle speed switch 17 can be adjusted so as to be opened at a speed of 5 ole/11 or higher, for example.

The carburetor having a float chamber with an air introduction switching valve according to this embodiment has an air introduction pipe attached to the upper space of the float chamber and an on-off valve at its tip (to prevent the fuel in the float chamber from forming bubbles). At 9 o'clock when the temperature and operating conditions are high, the on-off valve is opened to introduce air into the float chamber, and at other operating conditions or when the operation is stopped, the valve is closed to control engine rotation. It is possible to smoothly reduce the fuel consumption rate, and to reduce the amount of O harmful components in the exhaust gas.

In the above embodiment, the vehicle speed switch 17 and the temperature switch 18 are connected in series, but it is also possible to connect them in parallel to the power source and open the switching valve 10 when either one is connected. The effect of this can be obtained.

The carburetor of the present invention, which has a float chamber with an air introduction switching valve, uses gasoline containing many components with high vapor pressure, suppresses the generation of bubbles in the float chamber even at 9 o'clock, and enables smooth engine operation. Effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a carburetor having a float chamber with an air introduction switching valve, which is an embodiment of the present invention. 1...Float chamber, 4--Main jet, 6...
Main air bleed, 7- Main nozzle, 9...
Inner vent pipe, 10・φ・switching valve, 11-filter, 12-pulp, 13-... plunger, 14-...
Coil, 15--Air introduction pipe, 16--Spring, 1
7-...Vehicle speed switch, 18...Temperature switch. Agent Patent attorney Hiroshi Nagasaki (and 1 other person) Figure 1

Claims (1)

[Scope of Claims] 1. In a carburetor having nine float chambers, a passage communicating with an inner vent pipe opening downstream of the air cleaner and an inner vent pipe is provided in the upper space of the float chamber. An air introduction path is further connected to the air introduction path, and a switching valve is installed in this air introduction path, and under certain operating conditions, the switching valve is opened to introduce air, and under other operating conditions or when the engine is stopped. A carburetor having a float chamber with an air introduction switching valve, which is sometimes configured to close the switching valve. 2. A carburetor having a float chamber with an air introduction switching valve according to claim 1, wherein the predetermined operating condition is at least a fuel temperature above a predetermined value or a vehicle speed below a predetermined value. 3. A vaporizer having a float chamber with an air introduction switching valve according to claim 011111111, wherein the air introduction passage is a passage whose outlet to the float chamber is provided close to the fuel introduction needle pulp.