JPS5882052A - Idling operation improving apparatus for carburetor - Google Patents

Abstract

PURPOSE:To enable to execute accurate and fine control in a stable manner, by providing a control valve in an ''idle-up'' port having a slow-speed fuel passage branched therefrom, opening the ''idle-up'' port at a lower portion of a throttle valve, and controlling the opening of the control valve according to the load acted to the auxiliary machinery. CONSTITUTION:When a load is acted to the auxiliary machinery, a feedback circuit is disconnected immediately and solenoid valves 25, 26 are closed. On the other hand, an output signal S5 of a load detecting circuit 16 is applied to a constant-current circuit 50, which in turn gives a constant-current signal S6 to the solenoid valve 26 and opens the valve 26 again to a prescribed extent. At the same time, the output signal of the circuit 50 is also applied to another solenoid valve 32 and closes the same completely. Resultantly, fuel begins to be supplied also from an ''idle-up'' port 30 to enrich the air-fuel mixture and to thereby improve the idling operation. Here, in order to prevent the mixture from becoming too rich, atmospheric air is introduced in air-bleed manner into fuel supplied to a branched fuel passage 31 by opening the solenoid valve 26 to a prescribed extent.

Description

[Detailed description of the invention] The present invention relates to an idle-up device for a carburetor.

If an auxiliary device driven by the engine, such as an alternator, a power steering pump, or a cooler compressor, is loaded while the internal combustion engine is idling, the idling speed will drop and the rotation will become unstable.

In order to solve this problem, the carburetor is provided with an idle-up device that increases the idle speed as necessary. All of the conventional idle araf systems (flIId) are based on the concept of forcibly increasing the throttle valve opening of the carburetor when necessary. That is, for example, a throttle valve is connected to a Mayafu actuator that responds to intake negative pressure, and the intake negative pressure of this actuator is controlled by a solenoid valve that is turned on and off by a control circuit that detects the load on the auxiliary equipment. The opening degree of the throttle valve is mechanically controlled by opening/closing the throttle valve by connecting/disconnecting it.

However, it is very difficult to mechanically adjust the throttle valve by a small amount accurately in this way, and the rotation line d tends to wobble when idling up.

Therefore, the present invention does not directly open the throttle valve mechanically, but adds an amount of air-fuel mixture corresponding to the idle port downstream of the throttle valve in a method with a ratio of t#I*f5, which is equivalent to opening the throttle valve. It is an object of the present invention to provide an idle-up device which is designed to obtain the effect of increased speed.

Description will be given below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of an idle up device k' according to the present invention. The fuel in the float chamber 2 of the carburetor 1 passes through a fuel passage 4 via a main jet 3 and is discharged from a main nozzle 6 protruding into a small pentier 5. A main air bleed jet 7 is provided in the middle of the fuel passage 4 to make the fuel flow rate appropriate, and the fuel flows through a chain 8.
Air is bled through the small hole 9. On the other hand, the fuel in the passage 4 passes through the slow jet 10 to the slow system fuel passage 1.
1, the air is bleed by the slow air bleed jet 12, and is also discharged from the slow port 13 and the idle port 14. The idle port 14 has an idle adjusting screen 1 that adjusts the idle fuel.
5 will be established.

The above fuel system structure is publicly known. In such a fuel system, the exhaust gas concentration sensor (e.g., 0-heavy sensor) 27 has conventionally detected the 0 dew concentration in the exhaust gas, and the signal S, which has been detected by the control circuit 17, has been subjected to comparison calculation processing. Feedback control is performed to maintain the air-fuel ratio of exhaust gas at a desired value, for example, the air-fuel ratio cape. For this purpose, an auxiliary main air bleed passage 23 is provided in the middle of the main system fuel passage 4, and an auxiliary slow air bleed passage 24 is provided in the middle of the slow system fuel passage 11. These two auxiliary air bleed passages 2324 are each communicated with the flame via a control valve, for example in the form of a solenoid valve 25,26. Solenoid valve 25.26#'i control circuit 17
They are opened and closed based on the output signals s, , s, of the main system and the slow system to control the amount of air bleed to the fuel in order to always maintain the air-fuel ratio at a predetermined value.

In the fuel system as described above, according to the present invention, a branch fuel passage 31 is provided from the middle of the slow system fuel passage 11 to the idle up port 30 opened downstream of the throttle valve 22. An on-off control valve such as a Kd solenoid valve 32 is installed inside this passage 31, and the opening/closing control valve such as a Kd solenoid valve 32 is installed therein.
Opening/closing control.

As is well known, the control circuit 17 receives the output signal S of the 03 sensor 27.
, is compared with the reference value by the comparator 51, integrated by the integral 653, and outputted to the output port 55, and the valve 25.2 is outputted accordingly.
6 to perform feedback control of the air-fuel ratio.

According to Tanemei, the output signal S1 of the load detection circuit 16, which is known per se and detects the operation of the auxiliary equipment, is input to the control circuit 17, and when the auxiliary equipment we is loaded, the control circuit 17 is activated. Cut the signals S, , S, to the stop valves 25 and 26. For example, what if Sodekiso-ga-Mawari Steering Demp? It is good to detect this when the pump oil pressure exceeds the predetermined value, and in the case of a Nura compressor, to detect this when a load is applied to the compressor, that is, when the compressor starts to rotate. Additionally, if the auxiliary device is a light-weight electrical load, the voltage at the F terminal of the alternator may be used as the detection signal. That is, the feedback circuit is cut off as soon as a load is applied. At this time, the solenoid valves 25 and 26 are in the closed position i. On the other hand, the signal S of the load detection circuit 16.

A constant current K is sent to the circuit 50, which supplies a constant If (signal Ss) to the magnetic valve 26 to open the solenoid valve 26 again by a predetermined amount. On the other hand, a signal from the constant voltage #11 path 50 is also sent to the solenoid valve 32 to open the solenoid valve 32 (all open). As a result, fuel is also supplied from the idle up port 30, enriching the air-fuel mixture and producing the same effect as opening the throttle valve 22, that is, idle up. At this time, in order to prevent the mixture from becoming overrich, the fuel sent to the branch fuel passage 31 is shear-bleeded by opening a predetermined amount of the solenoid valve 26, and the atmosphere is introduced. Furthermore, it is also possible to provide the idle up/-) 30 with an adjuster such as the idle assist screen 15 in order to more accurately control the amount of idle up fuel. Solenoid valve 2
5, 26, 32ti is preferably a current proportional valve such as a linear solenoid valve.

FIG. 2 shows another embodiment of the present invention, in which a branch fuel passage 1831 having a solenoid valve 32 is provided in the slow system fuel passage 11 independently of the conventional air-fuel ratio feedback control circuit. It is something that In this case, the solenoid valve 2611 for feedback control is too powerful, so separate
A magnetic valve 33 is provided. The solenoid valve 33 bleeds air from the branched fuel passage 31 as in the case of FIG.
The atmosphere sucked through the port 34 is introduced into the carburetor fuel passage through the atmosphere port 35 separately from the fuel system. Similarly to the solenoid valve 26 in FIG. 1, the solenoid valve 33 opens based on a signal from the control circuit 50 to introduce atmospheric air and prevents the mixture from becoming rich due to the fuel from the idle ag port 30. .

Also in Figure 2, an adjustment souffler can be provided in one or both of the idle up port 30 and the atmospheric port 35.

Furthermore, fl! In the embodiment shown in FIG. 1, it is also possible to separately provide a solenoid valve 33 for introducing atmospheric air and an atmospheric port 35 as shown in FIG. In that case, there is no need to turn on the solenoid valve 26 once when the engine is idling up, so the energization of the solenoid valve 26 may be completely cut off when the engine is idling up.

As described above, according to the present invention, when idling up, the throttle valve is equivalent to idling up by supplying an extra amount of mixing fluid downstream of the throttle valve, without directly opening the throttle valve mechanically as in the conventional method. The minute I do it, I open my mouth. Since it is possible to obtain the same force effect as in the previous example, not only is there no need for a large actuator for idle up to mechanically open the throttle valve, but it also allows very precise and fine control. . Furthermore, in a nine-engine engine equipped with an air-fuel ratio six feedback control mechanism, it is sufficient to add one control valve corresponding to the solenoid valve 32.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional illustrative diagram showing one embodiment of the idle-up device according to the present invention, and FIG. 2 is #! FIG. 2 is a diagram similar to the m1 diagram showing the second embodiment. 1... Carburetor, 4... Main system fuel passage, 6...
Main nozzle, 11... Slow system fuel passage, 14...
・Idle port, 30...Idle ag port,
31... Branch fuel passage, 32... Control valve. Patent Applicant: Toyota Motor Corporation Patent Attorney: Akira Aoki, Patent Attorney, Kazuyuki Nishidate, Patent Attorney, Kyo Nakayama, Patent Attorney: Akira Yamaguchi! /S1 Figure 2

Claims (1)

[Claims] 1. A fuel passage is branched from the middle of a slow system fuel passage of a carburetor of an internal combustion engine to an idle up boat that opens below the throttle valve RI/c of the carburetor, and the fuel passage is opened and closed within the branched fuel passage. A control valve is provided, and the opening/closing control valve is connected to a load detection device that detects the load of the auxiliary device driven by a 1-meter barrier, and the control valve is connected to a load detection device that detects the load of the auxiliary device driven by a 1-meter barrier, and the control valve responds to the load of the auxiliary device based on the signal from the load detection device. A carburetor idle up device configured to control the opening/closing control valve. 2. The fuel passage leading to the idle up port that opens downstream of the throttle valve of the carburetor is branched from the middle of the slow system fuel passage of the carburetor of the internal combustion engine, and an opening/closing control valve is provided in the narrow branch fuel passage, and the branching An air bleed control valve is provided to air bleed the fuel in the fuel passage, and these opening/closing control valves and the air bleed control valve are connected to a load detection device that detects the load of auxiliary equipment driven by the engine. 2. The idle-up device for a carburetor according to claim 1, wherein the opening/closing control valve and the air bleed control valve are controlled to open/close in accordance with the load of the auxiliary equipment based on a signal from the auxiliary equipment. 3. Idle eye yf/ which opens downstream of the throttle valve of the carburetor from the middle of the slow system fuel passage of the carburetor of the internal combustion engine.
), and an on-off control valve is installed in the branched fuel passage, and an internal air introduction control valve for introducing atmospheric air separately from the on-off control valve is provided downstream of the throttle valve, and these on-off control valves and The air intake control valve is connected to a load detection device that detects the load of the auxiliary equipment driven by the engine, and the opening/closing control valve and the air introduction control are performed in response to the load of the auxiliary equipment based on the signal from the load detection device. An idle-up device for a carburetor according to claim 1, which controls opening and closing of a valve.