JPS5834667B2 - vaporizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carburetor for an internal combustion engine such as an automobile, and more particularly to an improvement in a power system incorporated in a carburetor.

Generally, carburetors used in internal combustion engines such as automobiles are equipped with a fuel system called a power system for enriching the air-fuel mixture to obtain high output mainly during high load or transient operation.

Such a power system generally includes a power fuel passage leading from the float chamber to the downstream side of the main jet in the main fuel passage (first high speed fuel passage). A valve device called a power valve is installed in front of the power jet, and is opened and closed by a negative pressure actuator that includes a power piston.

In this case, the power piston is slidably housed in a pressure chamber provided in a part of the carburetor body, is always urged toward the valve opening side by a spring, and is not introduced into the pressure chamber. The valve is configured to be biased toward the valve closing side by the negative pressure caused by the spring.

Conventionally, the pressure chamber of the negative pressure actuator configured in this manner is generally always connected to a negative pressure take-out port that opens into the intake passage at a position downstream from the throttle valve, and therefore, When the valve is moderately open, in other words, when operating under partial load, the negative pressure taken out from the negative pressure outlet port, that is, the intake manifold negative pressure, is relatively large, and this causes the spring to When the load increases and the throttle valve is opened fully or close to fully open, the intake manifold negative pressure taken out from the negative pressure take-out port becomes weaker, which causes the power piston to pull up and close the power valve. is pushed down by the spring and opens the power valve.

Thus, conventional power systems are opened only under heavy loads to supply additional fuel to the main nozzle.

By the way, in an internal combustion engine equipped with a carburetor, when the throttle valve is opened from the idling position when starting the car, the amount of air increases immediately according to the opening of the throttle valve, but the amount of fuel increases. (Gasoline) has a larger inertia than air, so there is a delay with respect to the increase in air flow rate, which makes it impossible to start the vehicle properly.
So-called breathing may occur.

Such problems occur particularly often when the engine is cold, and are even more likely to occur if the carburetor is set to perform lean combustion for the purpose of exhaust gas purification.

In view of the above-mentioned circumstances, it is an object of the present invention to provide a carburetor equipped with a fuel system that prevents breathing when starting a vehicle. The purpose is to achieve the above-mentioned object by utilizing a power system that improves drivability during high-load operation as described above.

According to the present invention, this object includes: a venturi section, a main nozzle opening into the venturi section, a throttle valve located downstream of the venturi section, a float chamber, and a main nozzle that passes from the float chamber through the main jet. a fuel passage leading to a nozzle; a power fuel passage leading from the float chamber to a downstream side of the main jet in the fuel passage; a valve device for selectively opening and closing the power fuel passage; and a fluid for operating the valve device. a pressure-actuated actuator, the fluid-pressure actuator being configured to close the valve device when a predetermined level of negative pressure is introduced into its pressure chamber, and the pressure chamber is configured to close the valve device when the throttle valve is in the closed position. A negative pressure delay valve is installed in the middle of the negative pressure outlet port 7 which is located upstream of the throttle valve and opens into the intake passage at a position downstream of the throttle valve when the throttle valve is opened beyond a predetermined opening degree. This is accomplished by a vaporizer such as one in communication with the

In particular, as described above, when the present invention is implemented to improve driving performance when starting a vehicle in a specific engine state such as when the engine is cold or hot, the pressure chamber of the fluid pressure operated actuator is It is connected in communication with the pressure take-out port via a negative pressure delay valve, and is selectively connected in communication with another negative pressure take-out port that is always open in the intake passage at a position downstream from the throttle valve. It's good that it's structured like that.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

FIG. 1 is a sectional view somewhat schematically showing the main parts of one embodiment of a vaporizer according to the present invention.

In the figure, 1 generally indicates a carburetor main body, that is, a body, and an intake passage 2 is formed within the body 1.

A large venturi 3 is formed in the middle of this intake passage 2, and a throttle valve 4 is rotatably provided on the downstream side of the large venturi 3, and an intake manifold is provided on the downstream side of the intake passage 2. 5.

A small venturi 6 is provided at the throat of the large venturi 3, and fuel is sucked out into the intake passage 2 through a main nozzle 7 that opens at the throat of the small venturi 6. .

Fuel (gasoline) from a float chamber 8 is supplied to the main nozzle 7 through a main fuel passage 10 while its flow rate is adjusted by a main jet 9 provided at the outlet of the float chamber.

Further, the float chamber 8 is provided with another fuel port 11 in addition to the fuel inlet for the main fuel passage where the main jet 9 is provided, and the fuel port 11 is provided with a power valve device 12 and a power valve device 12 on the way. Through a power fuel passage 14 including a power jet 13, the main fuel passage 10 is selectively communicated with the main fuel passage 10 on the downstream side 1 from the main jet 9.

The power valve device 12 is connected to the power fuel passage 14.
A valve seat 15 formed in the middle, a valve body 16 that blocks communication between the power fuel passage 14, and a compression coil spring 17 that presses the valve body 16 upward in the figure, that is, toward the valve seat 15. As shown in the figure, when the valve body 16 is lowered against the action of the compression coil spring 17, communication is established with the power fuel passage 14, whereas the valve body 16 is raised and the valve is closed. When the vehicle is seated on the seat 15, communication with the power fuel passage 14 is cut off.

The valve body 16 is configured to contact a power piston 19 of a negative pressure operated actuator 18 via its valve stem 16a.

The power piston 19 is mounted in a cylindrical pressure chamber 20 formed in a part of the body 1, in this embodiment, above the float chamber 8, in such a manner that it can reciprocate in the vertical direction as shown in the figure. A compression coil spring 21 provided in the pressure chamber 20 constantly exerts downward pressing force.

In this case, the compression coil spring 21 has a larger spring force than the compression coil spring 17, and therefore, when the pressure chamber 20 is below a predetermined negative pressure, the compression coil spring 21 acts on the valve body 16. Therefore, the valve is always subjected to a force that biases the valve toward the open position.

The pressure chamber 20 is located upstream of the throttle valve 4 when the throttle valve 4 is in the closed position (idling position) as shown in the figure, and is located upstream of the throttle valve when the throttle valve 4 is opened beyond a predetermined opening degree. It is connected to a negative pressure take-out port 22 provided to open into the intake passage 2 at a downstream position via a passage 24 including a negative pressure delay valve 23 in the middle.

In this case, the negative pressure delay valve 23 has a structure including an orifice throttle 025 and a check valve 26 in parallel, as shown in the figure.

The check valve 26 is configured to freely allow fluid to flow from the port 22 into the pressure chamber 20, but to prevent fluid from flowing in the opposite direction, that is, from the pressure chamber 20 to the port 22. There is.

The carburetor configured as described above operates as follows: First, when the throttle valve 4 is in the idling position as shown in the figure, the negative pressure take-out port 22 is located upstream of the throttle valve 4; Almost atmospheric pressure acts.

Therefore, at this time, the pressure inside the pressure chamber 20 is at atmospheric pressure, so the power piston 19 is pushed down as shown in the figure by the action of the compression coil spring 21, and the valve body 16 is also pushed down accordingly, causing the valve seat. Separated from 15.

That is, communication of the power fuel passage 14 is established.

However, at this time, since the amount of air passing through the bench and lily portions is small, the venturi negative pressure is small, and therefore no substantial fuel is sucked out from the main nozzle 7.

When the throttle valve 4 is opened to start or accelerate the vehicle in such a state, the amount of air passing through the venturi increases and the venturi negative pressure also increases, so that the main fuel metered by the main jet 9 flows from the main nozzle 7. The total fuel amount plus the fuel metered by the power jet 13 is sucked out, and the relatively rich air-fuel mixture required for such a start is created immediately without any response delay.

At this time, when one end of the throttle valve 4 is located slightly upstream of the negative pressure outlet port 22, substantial intake pipe negative pressure acts on the negative pressure outlet port 22; Since it is designed to be introduced into the pressure chamber 20 after passing through the orifice throttle 25 of the pressure delay valve 23,
The power piston 19 is not immediately pulled up due to such negative pressure.

That is, the power valve device 12 is never closed.

Operation at a throttle opening where one end of the throttle valve 4 is located slightly upstream of the port 22, that is,
When low or medium load operation (partial load operation) continues, the intake pipe negative pressure acting on the port 22 is reduced to the negative pressure delay valve 2.
The pressure is gradually transmitted into the pressure chamber 20 through the orifice restrictor 25 of No. 3, and when it eventually reaches a level where it overcomes the spring force of the compression coil spring 21, the power piston 19 resists the action of the compression coil spring 21. , the valve body 16 also moves upward, and the valve seat 15
will be seated.

In such a state, communication of the power fuel passage 14 is interrupted, and the communication from the power jet 13 to the fuel passage 10 is interrupted.
The supply of fuel to the main jet 9 is cut off, and only the economical amount of fuel metered by the main jet 9 and necessary for steady operation is sucked out from the main nozzle 7 into the intake passage 2 via the main fuel passage 10. Become.

That is, when the throttle valve is opened from the idling position to start or accelerate the vehicle, and then steady operation is performed under partial load, additional fuel is supplied from the power system for a predetermined period of time from the time of start (or acceleration).

In this case, the additional fuel supply time is appropriately set and balanced by the combination of the degree of restriction of the orifice throttle 25 of the negative pressure delay valve 23 and the spring force of the compression coil spring 21 of the negative pressure actuator 18.

Then, when the throttle valve is further opened in order to shift from steady operation under such a partial load to high load operation, and when it is opened fully or close to fully open, the negative pressure acting on the negative pressure outlet port 22 becomes weaker. The weakened negative pressure is applied to the orifice throttle 25 of the negative pressure delay valve 23 and the check valve 2.
6 and immediately into the pressure chamber 20, and the power piston 19 is pushed down again as shown in the figure by the spring force of the compression coil spring 21. The valve is pulled further apart and the valve opens.

That is, by re-establishing communication in the power fuel passage 14, at this time, the main nozzle 7 outputs the total amount of fuel, which is the sum of the amount of fuel measured by the main jet 9 and the amount of fuel measured by the power jet 13, as described above. Fuel is sucked into the intake passage 2, providing a relatively rich air-fuel mixture necessary for high-load or transient operation, similar to conventional power systems.

FIGS. 2 and 3 are sectional views showing, in a somewhat simplified manner, the main parts of another embodiment of the carburetor according to the present invention.

In Figures 2 and 3, the parts corresponding to Figure 1 are shown in Figure 1.
The same reference numerals as those in the figures are given.

In the embodiment shown in FIG. 2, the negative pressure outlet port 2
2, another negative pressure outlet port 27 opens into the intake passage 2 at a position downstream from the throttle valve 4.
The negative pressure outlet port 27 is connected to the passage 24 on the pressure chamber 20 side from the negative pressure delay valve 23 via a passage 29 having a thermovalve device 28 in the middle.

The thermovalve device 28 may be provided at a position that senses the engine cooling water temperature, for example, in order to be sensitive to the engine temperature. In this case, it detects when the engine cooling water temperature has reached a predetermined temperature corresponding to the engine warm-up state. When this occurs, the valve is opened to communicate with the passage 29, and when it is detected that the cooling water temperature is below the predetermined temperature in response to this force, the valve is closed and communication with the passage 28 is cut off.

In the case of such a configuration, when the engine is in a cold state, the thermovalve device 28 closes and blocks the passage 29, so the negative pressure actuator 18 that operates the power valve device 12 takes out the negative pressure. controlled by the negative pressure acting on port 22, and therefore at this time 7 as shown in FIG.
The same effect as in the embodiment described above is performed.

When the temperature of the engine sensed by the thermovalve device 28 reaches a predetermined temperature or higher, the thermovalve device 28 opens and establishes communication with the passage 29.

At this time, the resistance to flow of fluid through passage 22 becomes substantially greater than the resistance to flow of fluid through passage 29 due to the action of orifice restriction 25 of negative pressure delay valve 23, so that the pressure of negative pressure actuator 18 The pressure acting on chamber 20 becomes substantially controlled by the fluid passing through passageway 29.

Therefore, in this case, the power valve device 12 functions similarly to that incorporated in the power system of a conventional type carburetor, and opens only when the throttle valve 4 is fully open or close to fully open, and the power fuel Communication of the passage 14 is established.

In general, when starting a vehicle or in the early stages of transient operation, a rich mixture is required for a certain period of time when the engine is cold, and once the engine is warmed up, the normal conventional power system is activated. Normally, this does not impair drivability, and therefore, in the case of this embodiment, drivability when the engine is cold and hot is improved, and at the same time, fuel efficiency and exhaust gas are also improved.

The thermovalve device 28 may be configured to open and close by sensing, for example, the engine body temperature, atmospheric temperature, etc., in addition to sensing the engine cooling water.

The embodiment shown in FIG. 3 attempts to electrically perform the same operation as the embodiment shown in FIG.
Instead, a solenoid valve 30 (C) is provided in the middle of the passage 29.

In this case, the electromagnetic valve 30 is selectively supplied with current supplied from a battery power supply 31 or via a thermoswitch 32.

That is, when the engine is cold, the thermoswitch 32 is closed and the current supplied from the battery 31 is supplied to the solenoid valve 30, and the solenoid valve 30 interrupts communication with the passage 29. On the other hand, when the engine is warmed up, the thermoswitch 32 is closed. The solenoid valve 30 is configured to open and cut off the energization to the solenoid valve 30, so that the solenoid valve 30 establishes communication with the passage 29.

Incidentally, instead of the thermo switch 32, a shift switch that detects the shift position of a manual transmission of an automobile or the like may be incorporated. In this case, the switch is closed and the passage 29 The communication with the passage 28 may be established by opening a switch in the highest speed forward stage for economical operation, or by using other means such as an engine speed switch, a vehicle speed switch, a throttle opening switch, etc. It may be configured to control energization of the valve 30.

In the embodiment shown in FIGS. 2 and 3, a valve device is provided in the middle of the passage 29, but instead of a valve device, a valve device is provided at the connection between the passage 24 and the passage 29 in one of the passages. A flow path switching valve may be provided to selectively communicate only the pressure chamber 20 with the pressure chamber 20.

[Brief explanation of drawings]

FIG. 1 is a somewhat exploded sectional view showing the essential parts of one embodiment of the vaporizer according to the present invention, and FIGS. 2 and 3 respectively show the essential parts of other embodiments of the vaporizer according to the present invention. 1 is a somewhat exploded cross-sectional view; FIG. 1... Carburetor body, 2... Intake passage, 3... Large venturi, 4...
Throttle valve, 5...Intake manifold, 6...Small venturi, 7...
・Main nozzle, 8... Float chamber, 9...
... Main jet, 10 ... Main fuel passage, 11 ... Fuel inlet, 12 ... Power valve device, 13 ... Power jet, 14
...Power fuel passage, 15...Valve seat,
16... Valve body, 17... Compression coil spring, 18... Negative pressure actuator, 19... Power piston, 20...・
Pressure chamber, 21... Compression coil spring, 22...
... Negative pressure take-out port, 23 ... Negative pressure delay valve, 24 ... Passage, 25 ... 6 ... Orifice throttle, 26 ... Check valve, 27...Negative pressure outlet port, 28...Thermo valve device, 29
...Passage, 30...Solenoid valve, 31...
...Battery power supply, 32...Thermo switch.

Claims (1)

[Scope of Claims] 1. A venturi section, a main nozzle that opens into the venturi section, a throttle valve located downstream of the venturi section, a float chamber, and a main nozzle that communicates from the float chamber through a main jet. a fuel passage; a power fuel passage communicating from the float chamber to a downstream side of the main jet in the fuel passage; a valve device for selectively opening and closing the power fuel passage; and a fluid pressure operated type for operating the valve device. an actuator, the fluid pressure actuator is configured to close the valve device when a predetermined level of negative pressure is introduced into its pressure chamber, and the pressure chamber closes the valve device when the throttle valve is in the closed position. The intake port is located on the upstream side and is connected to a negative pressure outlet port that opens into the intake passage at a position downstream of the throttle valve when the throttle valve is opened beyond a predetermined opening degree, through a negative pressure delay valve. A vaporizer characterized by: 2. a venturi throttle section, a main nozzle opening into the venturi throttle section, a throttle valve located downstream of the venturi section, a float chamber, and a fuel passage leading from the float chamber to the main nozzle via a main jet. , a power fuel passage communicating from the float chamber to a downstream side of the main jet of the fuel passage, a valve device for selectively opening and closing the power fuel passage, and a fluid pressure operated actuator for operating the valve device. the hydraulic actuator is configured to close the valve device when a predetermined level of negative pressure is introduced into the pressure chamber, the pressure chamber being upstream of the throttle valve when the throttle valve is in the closed position. The first negative pressure outlet port is located on the side and opens into the intake passage at a position downstream from the throttle valve when the throttle valve is opened to a predetermined opening degree or more. The carburetor 0 is characterized in that the carburetor 0 is configured to be selectively connected to a second negative pressure outlet port that opens into the intake passage at a position downstream of the throttle valve. 3 In the vaporizer according to claim 2, the pressure chamber is opened and closed by a thermovalve device provided in the middle of a passage connecting the pressure chamber and the second negative pressure extraction port.
(b) selectively communicating with the second negative pressure outlet port. 4. In the vaporizer according to claim 2, the pressure chamber is opened and closed by the opening/closing operation of a solenoid valve provided in the middle of a passage connecting the pressure chamber and the second negative pressure extraction port. A vaporizer characterized in that the vaporizer is configured to selectively communicate with two negative pressure extraction ports.