JPS58158358A - Carburetor for internal-combustion engine - Google Patents

Abstract

PURPOSE:To eliminate effectively such a trouble as the occurrence of excessive rich fuel-air mixture at high temperatures without provision of a particular high temperature compensating system causing complication of the construction by an arrangement wherein a feedback carburetor system is utilized efficiently. CONSTITUTION:The opening area of an air bleed passage 11 in a main system 5 and that of an air bleed passage 12 in a slow-down system 8 are variably controlled by a feedback carburetor system 13. The slow-down system 8 is provided with a high temperature compensating means 21 adapted to increase quickly the area of open passage at a high temperature. The high temperature compensating means 21 is of a configuration which is obtained by removing the tip of a conventional needle 18b by a required length l and is arranged such that when the needle valve 18b is moved away from a valve seat's hole 18a beyond a control range at the normal temperature the area of an air passage 18c defined between the needle valve 18b and the valve seat hole 18a is increased quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carburetor Iζ for an internal combustion engine with a high temperature compensation function, which is mainly applied to automobiles.

For example, 1g on a hot day when the atmospheric temperature is 80℃ or higher.

If you continue to drive slowly or idle for a long time, the temperature inside the engine room will become abnormally high.

As a result, the density of the air supplied to the carburetor chamber is lower than that at room temperature, and the carburetor is more prone to percolation, making the air-fuel mixture supplied to the engine cylinders too rich. As a result, it is easy to cause problems such as the engine turning becoming unstable during idling and difficulty in restarting the engine immediately after stopping.

The present invention is intended to deal with such inconveniences, but as a prior art, as shown in Utility Model Application No. 58-107724, the carburetor has its terminal end opened near the closed position of the throttle valve. An air introduction path is provided, and a bimetallic conopenoseta valve is inserted in this air introduction path, and when the temperature is high, the 1ζ casting record conopenoseta valve is opened to replenish air from the air introduction path into the intake system path. There are things that I have made so that you can do it. However, such a system has the disadvantage that the configuration of air and air becomes complicated because the carburetor must be provided with an air introduction path that is independent of the fuel supply system.

By the way, in modern automobile internal combustion engines, the concentration of exhaust gas is detected using a sensor, etc., and the vaporization is started based on the detected value, mainly for the purpose of maximizing the exhaust purification performance of the three-way catalyst. I inserted into the air bleed passage of the device
! There are few vehicles that employ a so-called feedback carburetor system that can accurately maintain the air-fuel ratio of the mixture near the stoichiometric air-fuel ratio by opening and closing the lIm valve. It is designed to precisely control the air-fuel ratio of the air-fuel mixture at room temperature, and does not have a function that can deal with abnormal air-fuel ratio changes at high temperatures.

Therefore, even in a vehicle having such a feedback cab system, a high temperature compensation system as in the prior art described above is currently provided separately.

The present invention was made with attention to such circumstances, and
The purpose of this is to eliminate the disadvantage of over-rich mixture at high temperatures by cleverly utilizing the feedback carburetor system mentioned above, without requiring a special high-temperature compensation system that would complicate the configuration. An object of the present invention is to provide a carburetor for an internal combustion engine that can solve the above problems.

p) In order to achieve this object, the present invention
In the carburetor-ζ having the feedback carburetor system described above, a degree compensation means is provided to rapidly expand the open area of the air bleed passage at high temperatures, or
The first air bleed passage of the slow system is provided with a temperature compensation means for rapidly expanding the open circuit area of the air bleed passage when the temperature is high.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

Reference numeral 1 in the figure indicates a carburetor body inserted into an intake system passage 2 of an internal combustion engine (not shown), and this carburetor body 1 is a main system for guiding fuel in a float chamber 8 to a main nozzle 4 5, and a slow system 8 for guiding the Il fuel in the float chamber 8 to the slow boot 6 and idle port 7.Then, the air bleed passage 11 of the main system is opened. Cab system 1 feedbacks the area and the open area of the air bleed passage of Tsubagi slow system 8.
8 for variable control. The feedback cab system 18 includes an O sensor 15 which is an exhaust gas concentration detector provided in the exhaust system path 14 of the internal combustion MAI@, and a computer that statically controls the actuator 16 based on the feedback signal from the O sensor 15. and a pair of air bleed actuators inserted in each of the air bleed passages 11.11 and energized by the actuators 16+ξ to change the open area of the corresponding air bleed passages 11.12. Saving control valve 18.19
It is equipped with Each control valve 1819 has valve seat holes 18 &, 19 provided in the middle of each air bleed passage 11.12.
The needle 10.11k with an a4ζ taper is of the needle valve type made by Yu aS, and the needle 18a,
The air passage 1 is formed between the needle 18b119b and the valve seat holes 186, 198 by moving the needle 19m forward and backward in the axial direction by the actuator 16.
The open circuit area can be changed by 1%196.

In such a carburetor, the air bleed passage 121 of the slow system 8 is provided with a high temperature compensation means 21 for rapidly expanding the open area of the air bleed passage 12 when the temperature is high. The high temperature compensating means 21 has the needle 18b shaped like a conventional needle n (see the imaginary line of the second factor) by removing a required length l, and
The needle 18b reaches the valve seat hole IS beyond the IIIl range.
When separated from a, the needle 18b and the valve seat hole 1
It is constructed so that the area of the air passage 1gc formed in the darkness of 8 & can be rapidly expanded. Specifically, as shown in FIGS. 2 and 3, when the needle 18b is operating at the threshold between the stroke O (control valve 18 is fully closed) position and the stroke position, the control The amount of air bleed supplied to the carburetor body l through the valve 18 (dotted line a in Figure 8)
) changes in exactly the same manner as the air bleed amount by the conventional feedback carburetor system (solid line II in Figure 118), but the needle 1811 changes in the stroke d.
Range l from stroke 100 (total control valve lI)! , the air bleed amount (dashed line island) suddenly increases, and the amount of air necessary for temperature compensation at high temperatures is transferred to the vaporizer main body II.
This can be sent. The tip removal length l of the needle 18b is set to a value Iζ such that the needle 18b does not exceed the stroke during 10 mode and general running at room temperature. Note that if the operating range of the actuator 16 is expanded, the eighth
It is also possible to provide a characteristic as shown by a dashed line C in the figure.

With such a configuration, during normal driving at room temperature, the actuator 16 operates based on the feedback signal from the %01 sensor 15, and the needle tab moves between stroke and stroke to adjust the air-fuel ratio. The air/fuel ratio is maintained near the stoichiometric ratio as usual. - 10,000, if the high temperature causes percolation etc. If the aiki becomes too concentrated, 0. Since the sensor 16 continues to output a signal indicating that the amount of air bleed should be increased, the needle 18b moves beyond the stroke 10o in the direction of the stroke 10o. As a result, the open area of the air bleed passage 12 rapidly expands, a large amount of air is supplied to the slow system 8, and the over-enrichment of the air-fuel mixture is eliminated. Therefore, if it is something like a engine, even if you do not install a special high temperature compensation system, the mixture will become too rich at high temperatures, making the engine rotation rate unstable at idling, and restarting the engine will be difficult. It is possible to eliminate the inconvenience of becoming unsightly. Anyway, feedback cab system 13
As a precautionary measure to prevent the air-fuel mixture from forming at high temperatures by using - It is possible to extend the stroke while keeping the flow rate unchanged (see the two-dot chain line e). However, if the control flow rate per stroke is increased, feedback at room temperature □ Cab system 181
As a result, 84In becomes sensitive, making it difficult to perform stable air-fuel ratio control. In addition, if you try to extend the needle stroke to obtain the air flow rate necessary for high temperature compensation, the needle stroke will become long (so when you start accelerating, there will be a delay in the needle returning to its normal position). On the other hand, according to the configuration of the present invention, the amount of air bleed can be increased only when there is a possibility that the air-fuel mixture becomes extremely rich. An advantage is that appropriate high temperature compensation can be performed without adversely affecting the original air-fuel ratio control by the cab system.

Note that the structure of the high temperature compensation means is of course not limited to that of the embodiment described in AU. For example, as shown in FIG. It may also be something that can be changed suddenly. In other words, the high temperature compensation means 211 shown in Figure @4
The bimetal 22, which reverses its position as shown in the image line only when the temperature is high, is connected to the air bleed passage! H) A valve seat hole 24& is provided in which the needle 24b of the bimetallic two-way center control valve 24 is loosely fitted.

Further, in the above embodiment, the case where the high temperature compensating means is provided only in the air bleed passage of the slow system -ζ has been described, but the first aspect of claim 1 is not necessarily limited to such a case. Of course, for example, a high temperature compensation means may be provided in the air bleed passage of the slow system and the air bleed passage of the main system. However, at high temperatures, particularly during idling and restarting, which are particularly prone to inconvenience, the throttle valve is closed, so the amount of air taken into a portion of the venturi is extremely small. Therefore, 1. Even if the air bleed amount of the main system is increased in such a state, air cannot be effectively introduced into the intake system passage. - Since the end of the slow system opens at the closed position of the throttle valve, increasing the amount of air bleed in the slow system will not depend on the throttle opening (air can be transferred to the effective heat intake system path). You can introduce it.

Therefore, simply providing high temperature compensating means only in the air bleed passage of the slow system can sufficiently eliminate the inconvenience at high temperatures. In other words, if the slow system air bleed passage - ζ high temperature compensation means is provided, it is advantageous to prevent the mixture from being too rich during idling and restarting, and the main system air bleed passage Ir
- If a high temperature supplementary means is provided, no force will be applied when interrupting medium to high temperatures)
This is advantageous in correcting cases where the air-fuel mixture becomes too rich due to the following reasons. It is impossible to expect an effect more than an additive effect by providing high temperature compensation means in both the air bleed passages of the slow system and the main system. Eliminating the disadvantages mentioned above at high temperatures - this is the most effective way to control the amount of air bleed in the slow system, and is often sufficient. The vise has 5 adjustable forces; 9 easy and practical.

The present invention provides an appropriate high temperature compensation function to the feedback kip system having the configuration as described in 1 below.
Therefore, it is possible to provide a carburetor for an internal combustion engine that can effectively eliminate the disadvantage of the air-fuel mixture becoming too rich at high temperature N without providing a special high temperature compensation system.

[Brief explanation of the drawing]

Fig. m1 to Fig. 8 show an embodiment of the present invention, Fig. 81 is a schematic explanatory diagram, Fig. 2 is an enlarged sectional view showing the main part, and Fig. i@8 is a diagram showing the characteristics of the control valve. Figure 4 is a sectional view showing another embodiment of the present invention. 5... Main system 8... Slow system 11.12
, 2B... Air bleed path 18... Exhaust gas installation detector (O, sensor) 16... Actuator
17--Control device 18.19.24--Control valves 188, 19 &, 246--Valve seat hole 18b,
19b, 24b... Needle 21. 21'... High temperature compensation means 22... Bimetal agent Patent attorney Hiroshi Akazawa Figure 2 Figure 3 (total 1"a) =-,, llz X l-0 -ri (t
Figure 4

Claims (1)

[Scope of Claims] (1) A control device that controls the operation of an actuator based on an feedback signal (from an exhaust gas concentration detector); A vaporizer equipped with a control valve for adjusting the amount of air bleed that changes the area of the air bleed passage, characterized in that a high temperature compensation means is provided for rapidly expanding the area of the air bleed passage at high temperatures. A carburetor for internal combustion engines. (2) The control valve described in If is a needle valve type in which a tapered needle is loosely fitted into the valve seat hole,
The high temperature compensating means removes the pointed part of the needle, so that when the needle moves away from the valve seat hole beyond the control range at room temperature, a point is formed between the needle and the valve seat hole. 41JII for an internal combustion engine according to claim m, characterized in that the air passage is configured such that both sides of the air passage can rapidly expand. (-Claim 1) characterized in that the compensating means is constructed so that the open circuit i product of the air bleed passage can be suddenly changed by using a bimetal that changes its posture only when the temperature is high. A carburetor for an internal combustion engine according to the above. 9 - In a carburetor equipped with a control valve for adjusting the amount of air bleed that changes the one-way area of the air bleed passage, only the air bleed passage of the slow system can suddenly change the one-way area of the air bleed passage at high temperatures. A carburetor for an internal combustion engine, characterized by a carburetor provided with high temperature compensation means for increasing the temperature.