JPS6056258B2 - Air fuel ratio control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-fuel ratio control device, and particularly to a main system fuel flow for a carburetor of an automobile engine.

The present invention relates to an air-fuel ratio control device that controls the air-fuel ratio of a carburetor by controlling the amount of air bleed to the road. Generally, in an automobile engine, it is better to have a lean air-fuel ratio in order to improve fuel efficiency.

On the other hand, from the viewpoint of drivability, it is required to make the air-fuel ratio rich. Furthermore, when the engine temperature is high or when operating in high altitude areas, it is necessary to improve drivability by preventing the air-fuel ratio from becoming rich. Therefore, in order to improve engine drivability and economical efficiency, it is necessary to provide highly responsive and accurate control according to engine operating conditions, that is, engine vacuum, engine temperature, engine speed, etc. The first step is to optimally control the air-fuel ratio.
desired by. However, in conventional systems that control the air-fuel ratio by supplying air to the main fuel passage, a diaphragm-driven valve is opened and closed using a pressure signal from engine vacuum, etc., to control the amount of air flowing in. was. However, since this diaphragm-driven valve controls the air inflow by turning it on and off, it is not possible to control the air-fuel ratio with excellent responsiveness and control accuracy.
This was also one of the causes of deterioration in engine drivability or operational reliability. Therefore, an object of the present invention is to improve the responsiveness and control accuracy of air-fuel ratio control.

In order to achieve the object, the present invention converts a signal sent from a sensor that detects the operating state of the engine into an electrical signal by a computer, and controls the flow rate of air supplied to the air bleed by an electrically operated system that operates in response to the electrical signal. The electric flow rate control valve proportionally controls the flow rate, and the electric flow rate control valve generates a magnetic flux perpendicular to a bobbin that is slidably disposed on the iron core and the winding of the electromagnetic coil wound on the bobbin. a pair of permanent magnets arranged to pass through, a yoke forming a magnetic circuit together with the iron core by magnetic flux generated from the permanent magnets, and an opening hole inserted and fixed to the inner periphery of the bobbin and formed on the iron core. It has a configuration that controls the opening area of.

By adopting the above configuration, the bobbin is moved in the axial direction on the iron core by an electric signal sent from the computer, and the slide valve integrally connected to the bobbin slides on the opening hole on the iron core, and the opening area of the opening hole is moved. Since it controls
The air flow rate supplied to the air bleed is proportionally controlled.

Therefore, it is possible to reliably adjust the air-fuel ratio of the engine with good responsiveness and accuracy in accordance with the operating state of the engine, and the drivability and operational reliability of the engine can be significantly improved. By the way, in order to improve the responsiveness and control accuracy of air-fuel ratio control, it is known that a proportional solenoid valve operated by an electric signal is used instead of the 0N-OFF operated diaphragm-driven valve described above. ,
An example thereof is disclosed in Japanese Patent Application Laid-Open No. 52-74121.

That is, in this proportional solenoid valve, two cylindrical yokes are arranged concentrically so as to be in contact with the end face of a disc-shaped magnet, and the air bleed passage is controlled by a needle valve connected to a bobbin around which a coil is wound. It is something. Like this,
By adopting a needle valve, a large gap is required to open the valve due to the phenomenon that the valve sticks to the valve seat, and the area of the air bleed passage immediately after the valve opens and immediately before the valve closes. There are problems such as the fact that control cannot be carried out proportionally and accurately. In particular, when trying to increase the maximum flow rate of the air bleed passage, it is necessary to increase the diameter of the passage where the valve seat is formed, and the above-mentioned phenomenon of the valve sticking to the valve seat becomes noticeable, making it difficult to open the valve. A larger electromagnetic force is required to make this happen. On the other hand, in the structure of the present invention, the slide valve integrally connected to the bobbin slides on the iron core, so the sticking phenomenon when the valve is opened is reduced compared to the case of the needle valve structure. few.

Further, the flow rate characteristics with respect to the input current can be easily adjusted by changing the opening area of the opening hole in the iron core. An embodiment of the present invention will be described below with reference to the accompanying drawings.

The carburetor 10 includes a slotted valve 11 that is rotated by an accelerator pedal, and the upstream side of the slotted valve 11 is continuously connected to a bench lily 12 and an air cleaner 13, and the downstream side thereof is connected continuously to an intake manifold 14 and a combustion chamber 15 of the engine E. There is. The ventilator vacuum sensor 16 detects the vacuum generated in the intake manifold 14 and sends the vacuum signal to the computer C.The manifold vacuum sensor 17 detects the vacuum generated in the intake manifold 14. , the vacuum signal is sent to the computer C in the same way.Furthermore, a water temperature sensor 19 attached to the cylinder block 18 of the engine E detects the engine cooling water temperature and sends the temperature signal to the computer C in the same way. The fuel supplied to the main system fuel passage 20 is exposed in the carburetor 10 through the main nozzle 21.The main system fuel passage 20 has an air bleed 2 for introducing air.
2 are arranged. The electric flow rate control valve 30 controls the supply of clean air from the air cleaner 13 to the air bleed 22 . The body 31 of the valve 30 has an inlet boat 32 communicating with the air cleaner 13 via a passage 13a, and an air bleed 22 with a passage 22a.
An outlet boat 33 communicating with each other via the outlet boat 33 is provided respectively. The cover 34 is integrally and airtightly connected to the body 31 via a sealing material 35. A bobbin 37 made of a non-magnetic material is slidably disposed on an iron core 36 made of a magnetic material, and an electromagnetic coil 38 is mounted on the bobbin 37.
is wrapped. Further, a pair of permanent magnets 39 and 40 are arranged so that magnetic flux passes perpendicularly to the winding of the electromagnetic coil 38, and a magnetic yoke 41 having a substantially U-shaped cross section surrounds the permanent magnets 39 and 40. The movable coil type linear motor 42 is configured. A guide member 43 is provided on the inner periphery of the yoke 41, and the permanent magnets 39, 40 are held by the guide member 43. The iron core 36 is provided with a plurality of opening holes 44 that communicate between the hollow portion 36a in the front interior thereof and the outer peripheral portion 36b thereof.

Of course, the hollow portion 36a communicates with the inlet boat 32 via the passage 32a, and the outer peripheral portion 36b communicates with the outlet port 33 via the passage 33a. Further, an air filter 45 is disposed in the hollow portion 36a, and impurities in the air are removed by the filter 45. Bobbin 37
A slide valve 46 is inserted and fixed into the inner periphery of the electromagnetic coil 3, and the valve 46 slides on the opening hole 44.
The opening area of the opening hole 44 is controlled in response proportion to the current value applied to the opening hole 8. Two coil springs 47 and 48 having different center diameters are stretched in the guide member 43, and the slide valve 4 is
6 is always located to the left in the figure through the bobbin 37, that is, the opening hole 4
4 is biased to the fully closed position, and normally comes into contact with a valve seat 49 consisting of an O-ring as shown. One end of each of the springs 47, 48 is connected to both ends of the electromagnetic coil 38, respectively. The terminal terminals 50, 51 are connected to the computer C via lead wires 52, 53. Next, the operation of the air-fuel ratio control device having the above configuration will be explained.

First, regarding the electric flow control valve 30, under normal conditions, magnetic flux generated from the permanent magnets 39 and 40 forms a closed loop via the iron core 36 and the yoke 41, and a portion of the closed loop is connected to the electromagnetic coil 38. In this state, when electricity and signal current from the computer C are applied to the electromagnetic coil 38, a force proportional to the applied current value is generated in the direction of the arrow shown in the figure, according to the well-known Fleming's left hand rule.
Therefore, along with the operational displacement of the bobbin 37, the slide valve 4
6 is actuated and displaced to the right in the figure against the urging force of springs 47 and 48, and the opening is opened. Open the mouth hole 44. The opening hole 44 has a sufficient length in the axial direction, and the opening area of the opening hole 44 is controlled in proportion to the rightward displacement position of the slide valve 46. As a result, the flow rate of air flowing between both boats 32 and 33 is controlled in direct proportion to the magnitude of the applied current value. Now, the signals sent from the bench lily vacuum sensor 16, the manifold vacuum sensor 17, and the water temperature sensor 19 are converted into electrical signals by the computer C, and the electrical signals actuate the electrical flow control valve 30 as described above. ing.

Therefore, during normal driving, the amount of air flowing into the air bleed 22 is increased to make the air-fuel ratio lean, and during acceleration, the amount of air flowing is decreased to make the air-fuel ratio rich, improving drivability. . Furthermore, when the engine temperature is high, the amount of air flowing into the air bleed 22 is increased to prevent the air-fuel ratio from becoming rich.

[Brief explanation of the drawing]

The drawing is a system diagram showing one embodiment of the air-fuel ratio control system of the present invention. 10: Carburetor, 13: Air cleaner, 13a: Passage, 16: Bench valve vacuum sensor, 17: Manifold vacuum sensor, 19: Temperature sensor, 20: Main system fuel passage, 22: Air bleed, 22a: Passage, 3
0: Electric flow control valve, 36: Iron core, 37: Bopin, 38: Electromagnetic coil, 39, 40: Permanent magnet, 41: Magnetic yoke, 42: Moving coil type linear motor, 44:
Opening hole, 46: valve.

Claims (1)

[Claims] 1. An air passage that communicates an air bleed provided in the main system fuel passage of the engine carburetor with an air cleaner;
A sensor that detects the operating state of the engine, a computer that converts a signal sent from the sensor into an electrical signal, and an electric flow rate that proportionally controls the air flow rate of the air passage in response to the electrical signal sent from the computer. The electrically operated flow valve is arranged such that magnetic flux passes at right angles to a bobbin that is slidably disposed on an iron core and a winding of an electromagnetic coil wound on the bobbin. A pair of permanent magnets are provided, and a yoke forms a magnetic circuit with the iron core by magnetic flux generated from the permanent magnets, and an opening area of an opening hole formed on the iron core that is inserted and fixed to the inner periphery of the bobbin. An air-fuel ratio control device having a slide valve to control.