JPH01237346A - Electronically controlled carburetor - Google Patents

Abstract

PURPOSE:To dispense with a choke valve as well as enhancing the controllabity of a carburetor by disposing a fuel metering pump driven by an electric motor controlled by a computer in a main fuel passage reaching a main fuel nozzle and setting a fuel flow supplied to a main air intake passage correctable. CONSTITUTION:A carburetor is provided with a main fuel system in which the fuel staying inside a float chamber 106 is metered by means of a main fuel jet 107 and supplied from a main fuel nozzle 108 into a main air intake passage 102 through a main fuel passage 109, Meanwhile, it is also provided with a low speed fuel system which is branched from the main fuel passage 109 and supplies fuel from a low speed fuel injection port 112 into the main air intake passage 102 through a low speed fuel passage 113 in the way of which a low speed fuel jet 114 is interposed. In this case, a fuel metering pump 117 is installed in the upper course from the branching position of the low speed fuel passage 113 but in the lower course from the main fuel jet 107. This pump 117 is controlled in its drive in response to the operating conditions of an engine by means of an electric motor 116 controlled by a computer.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a main fuel meter in which fuel in a float chamber is metered by a main fuel jet and is supplied through a main fuel passage from a main fuel nozzle into a main intake passage. A system that branches from the main fuel passage and passes through a low-speed fuel passage in which a low-speed fuel jet is disposed, and a throttle valve disposed in the main intake passage on the downstream side of the main fuel nozzle is opened when idling. a low-speed fuel system in which fuel is supplied into the main intake passage from a low-speed fuel nozzle that opens on the inner wall surface of the main intake passage near the periphery of the throttle valve when the throttle valve is in the In the main fuel passage, an electric motor-driven fuel pump whose rotational speed is controlled by a computer (including reverse rotation) is provided upstream of the low-speed fuel passage branch position and downstream of the main fuel jet. Place the
When starting and warming up the engine, when fully open at low speed, when accelerating, increase the amount of fuel, cut fuel when decelerating, change the density of intake air due to changes in atmospheric pressure and temperature. This invention relates to an electronically controlled carburetor that can perform feedback control of fuel flow rate using a 02 sensor signal attached to an exhaust pipe.

[Prior Art] Fig. 13 shows a fixed venturi carburetor with the simplest configuration, which is equipped with a main fuel system and a low-speed fuel system, and a butterfly-shaped throttle valve as a throttle valve, and is a carburetor to which the present invention is applied. The structure of the device is shown, where 1 is the carburetor casing and 2 is the main intake passage.
, 3 is a butterfly throttle valve, 4 is a fixed venturi, 5 is an inner
A venturi, which is arranged concentrically with the fixed venturi 4. 6 is a float chamber, 7 is a main fuel jet, 8 is a main fuel nozzle opening into the fixed venturi (in detail, an inner venturi 5 arranged concentrically with the fixed venturi 4);
9 is a main fuel passage that connects the float chamber 6 and the main fuel nozzle 8. In the configuration shown in FIG. A bleed tube 11 is disposed that mixes the fuel passing therethrough as bubbles. FIG. 13 shows the state in which the butterfly-shaped throttle valve 3 is at the idling opening position. A plurality of low-speed fuel nozzles 12 are opened and communicated with a low-speed fuel passage 13 branched from the main fuel passage 9 . A low-speed fuel jet 14 is arranged in the low-speed fuel passage 13 to meter low-speed fuel, and a low-speed air jet 15 is arranged, and the air metered by the low-speed air jet 15 is mixed into the fuel as bubbles. be done. The main fuel jet 7 and the main fuel nozzle 8
, the main fuel passage 9, and the main air jet 10, the main fuel system includes the low speed fuel passage 13, the low speed fuel jet 14,
The low-speed fuel nozzle 12 and the low-speed air jet 15 constitute a low-speed fuel system. Reference numeral 16 denotes a choke valve, which is closed when the engine is started to increase the negative pressure in the main intake passage 2, that is, the force to suck in fuel, thereby increasing the fuel flow rate at the time of engine startup. The above can be said to be the basic configuration of a carburetor, but since it is difficult to control the fuel flow rate appropriately for the various operating conditions of the engine, the carburetors currently in common use are as follows. It has a complex configuration with means for responding to each engine operating condition described in .

(1) Starting and warming up the engine In order to increase the amount of fuel by increasing the negative pressure acting on the tip of the main fuel nozzle, a choke valve, indicated by reference numeral 16 in Fig. 13, is installed and works in conjunction with the choke valve. A link mechanism is provided to open the spiral throttle valve 3 to a greater extent than the idling opening.

(2) High-load low-speed operation of the engine (hereinafter referred to as full-open low-speed operation) In the carburetor configured as shown in Fig. 13, in order to increase the maximum output of the engine, the diameter of the main intake passage 2, that is, the butterfly-shaped throttle It is desirable to increase the diameters of the valve 3 and fixed venturi 4, but if the diameter of the fixed venturi 4 is increased,
When the load on the engine is large, the butterfly throttle valve 3 is fully open or close to fully open, and the engine rotation speed is low, the air flow rate of the fixed venturi 4 decreases and the main fuel Negative pressure that overcomes the head difference between the open end of the nozzle 8 and the oil level in the float chamber 6 is not generated at the tip of the main fuel nozzle 8, and fuel does not flow out from the main fuel nozzle. The above-mentioned phenomenon becomes more noticeable as the diameter of the fixed venturi 4 increases. As a measure to satisfy full-throttle low-speed operation, it is called a compound (compound) type carburetor or two-stage (two-stage) type carburetor, which has two main intake passages 2 and a butterfly valve placed in each. A carburetor in which the throttle valve 3 opens and closes in two stages, or a variable venturi carburetor in which the opening area of the venturi through which the main fuel nozzle 8 opens changes in accordance with the intake air flow rate flowing through the main intake passage 2 is used. There is.

(3) Engine transient operation throttle valve. In the configuration shown in Figure 13, the butterfly-shaped throttle valve 3 is opened to compensate for the delay in the start of fuel when accelerating the engine. In conjunction with the rotating shaft of the throttle valve 3, the amount of fuel is increased during acceleration.

(4) Fuel flow rate control that feeds back the composition of exhaust gas In order to comply with engine exhaust gas regulations, there is an electronically controlled carburetor that computer-controls the fuel flow rate based on a signal from an 02 sensor attached to the exhaust pipe.

In the electronically controlled carburetor, the main fuel passage 9 and the low speed fuel passage 13
The fuel flow rate can be controlled either by placing a solenoid valve inside the engine to directly control the fuel flow rate, or by placing a solenoid valve in the bleed air intake section of the main fuel system and slow fuel system to control the bleed air flow rate. ing. (For example, Tokuko Sho 53-1
No. 6451) (5) Altitude correction control In order to maintain the air-fuel ratio of the mixture appropriately against changes in air density due to changes in atmospheric pressure, the so-called altitude adjustment valve adjusts the bleed air in the main fuel system and low-speed fuel system. By adjusting the amount, the air-fuel ratio of the mixture flowing into the engine is adjusted.

(6) Fuel cut control Fuel cut during deceleration, so-called coasting cut, is performed by cutting off the fuel passages between the main fuel system and the low-speed fuel system using electromagnetic valves during deceleration.

As mentioned above, even though the basic configuration of a carburetor is simple as shown in Figure 13, it is currently being produced by adding individual auxiliary equipment to individually perform the various functions listed above. The carburetor has a complex construction, as illustrated, for example, in the Mechanical Engineering Handbook below. However, this diagram does not include a mechanism for attaching an 02 sensor to the exhaust pipe to perform feedback control of the fuel flow rate.

First edition published on October 30, 1985 Published by Japan Society of Mechanical Engineers Mechanical Engineering Handbook Applied Edition B7 Internal Combustion Engine Chapter 4 Spark Ignition Engine Page B7-99 Figure 231 Twin-barrel carburetor An electronic fuel injection device is used that actively injects fuel from an electromagnetic injection valve into the intake passage of the engine, controls the valve opening time of the electromagnetic injection valve by a computer, and controls the fuel flow rate in accordance with engine operating parameters. Also, JP-A-62-174555
No. 2, No. 2003-116919 discloses a carburetor configuration in which an electromagnetic reciprocating piston pump is placed in a fuel passage of a separate system independent of the main fuel system and the low-speed fuel system, and corrective fuel is forcibly supplied under computer control. A fuel system diagram of the carburetor is shown in block diagrams in FIGS. 14 and 15.

Fig. 14 is a block diagram depicting the conventional components of the carburetor in one frame, and Fig. 15 shows the main fuel system,
It is a diagram showing a low-speed fuel system and an independent fuel system that supplies correction fuel under electronic control. 14 and 15 will be described later in comparison with the operation of the carburetor of the present invention when explaining the operation of the carburetor of the present invention.

[Problem to be solved by the invention] As mentioned above, even though the basic structure of the carburetor is simple, in order to satisfy all engine operating conditions, it is necessary to correct the fuel flow rate according to each condition. Since the general configuration is based on the idea that each correction element is handled by one independent device (auxiliary equipment), the overall configuration is extremely complex, and each correction element is The machine also has the following problems.

(1) When the acceleration pump driver depresses the accelerator pedal to accelerate the vehicle, the butterfly-shaped throttle valve 3 opens and the acceleration pump operates in conjunction with the rotation axis of the butterfly-shaped throttle valve 3. , a certain amount of fuel is injected and supplied into the main intake passage 2, but the air-fuel ratio of the mixture required by the engine during acceleration depends on the engine rotation speed before acceleration, the degree of load, the engine cooling water temperature, Depends on a number of engine operating parameters such as atmospheric temperature;
In addition, since the time for which acceleration fuel should be continued to be supplied differs depending on the condition 1, it is difficult to accurately correct the fuel flow rate with the conventional carburetor acceleration pump device configured with a simple link mechanism. The amount of fuel to be supplied is set.

(2) Choke valve The air-fuel ratio of the air-fuel mixture required by the engine differs between when the engine is cranking and when it is being warmed up after a complete explosion. The air-fuel ratio of the air-fuel mixture differs depending on engine operating parameters such as atmospheric temperature and engine cooling water temperature, so with a choke valve that has a simple mechanical configuration, it is extremely difficult to correct the fuel flow rate as strictly as with an accelerator pump. Yes, it is set as a compromise to some extent. Since the carburetor is basically a passive structure that depends on the negative pressure generated by the air flow, it can be adapted to a fairly high degree for the steady operating conditions of the engine. Significant compromises must be made for operation outside of normal conditions, while the electronic fuel injection system described above imposes high pressure inside the fuel piping system, including the fuel filter, fuel pressure regulator, and fuel pump. In addition, since all fuel supplied to the engine is controlled by a computer, there is a problem in that if a computer malfunctions, the engine, and therefore the vehicle, will be unable to operate at all. Japanese Patent Publication No. 6'2-17455
In the configuration disclosed in No. 5, the electromagnetic reciprocating piston pump consists of two check valves as a suction valve and a discharge valve, and a reciprocating piston pump with a small stroke, and is formed between the two check valves and the piston. Even if there is a small amount of air or fuel vapor bubbles in the pump action chamber, it will not only cause fluctuations in the fuel supply capacity, but also cause the check valve to be unable to follow the reciprocating movement of the piston, resulting in a decrease in the fuel flow. There is a problem in that it is difficult to appropriately correct the amount. Break away from the idea of one auxiliary device for one function (one function, one device) in conventional carburetors, and perform all necessary corrections centrally and appropriately with one auxiliary device. It is an object of the present invention to obtain a simple-configured and inexpensive vaporizer that can perform the following steps.

[Means for Solving the Problem] A main fuel system in which fuel in the float chamber is metered by a main fuel jet and supplied into the main intake passage from a main fuel nozzle that opens into the venturi through a main fuel passage; A throttle valve disposed in the main intake passage on the downstream side of the main fuel nozzle is at an idling opening degree through a low-speed fuel passage that branches from the main fuel passage and has a low-speed fuel shed disposed therebetween. In the carburetor, the carburetor is provided with a low-speed fuel system in which fuel is supplied into the main intake passage from a low-speed fuel nozzle that opens on an inner wall surface of the main intake passage in the vicinity of a periphery of the throttle valve. A fuel metering pump operated by a computer-controlled electric motor is disposed upstream of the low-speed fuel passage branch position and downstream of the main fuel jet, and a computer inputs various engine operating parameter signals. energizes the electric motor according to the output signal of the motor, controls the rotational speed, and corrects the fuel flow rate caused by the intake negative pressure generated in the main intake passage 2 according to the operating state of the engine;
It performs exactly the same function as an electronic fuel injection system. That is, (1) Fuel increase correction during high load operation (including full throttle low speed and high output operation), acceleration, startup/warm-up operation: Fuel increase correction is performed by operating the fuel metering pump in the forward direction.

(2) Fuel cut during deceleration: The time to cut fuel is determined by a computer based on the engine rotational speed and the opening degree of the throttle valve, and the fuel cut is performed by reverse rotation of the fuel metering pump.

During deceleration, the air flow velocity in the main intake passage is very low, so the negative pressure is very weak, and therefore the fuel suction force acting on the main fuel nozzle is very weak. Therefore, by reverse rotation of the fuel metering pump, the main fuel The fuel oil level in the passage easily drops to the fuel metering pump position, and there is no fuel at the branch position of the low-speed fuel passage, so the flow of fuel from both the main fuel nozzle and the low-speed fuel injection port is stopped. be able to.

(3) Feedback control of fuel flow rate using 0□ sensor signal: Sets the mixture in the carburetor to be leaner than the theoretical mixture ratio,
The fuel metering pump rotates in the positive direction to increase the amount of fuel when the 02 sensor signal indicates that the mixture is lean, and stops rotating when the 0□ sensor signal indicates that the mixture is too rich. do.

(4) Atmospheric pressure correction: The fuel metering pump rotates in the forward direction to compensate for the increase in fuel flow when the atmospheric pressure is higher than the standard atmospheric pressure, and in the opposite direction when the atmospheric pressure is lower than the standard atmospheric pressure. to correct the fuel flow rate.

(5) Intake air temperature correction: When the temperature of the intake air is higher than the standard atmospheric temperature, the fuel metering pump rotates in reverse to compensate for the reduction in fuel flow, and when the temperature of the intake air is lower than the standard atmospheric temperature, the fuel metering pump The metering pump rotates in the forward direction to increase the fuel flow rate.

The forward or reverse rotational speed of the fuel metering pump for increasing or decreasing the fuel flow rate as described above, and therefore the current or voltage to be applied to the electric motor, are theoretically and experimentally determined based on the engine speed. Each value of various engine operating parameters is determined based on the predetermined increase or decrease correction flow rate determined by operation and the characteristics of the fuel metering pump and electric motor, and is stored in the computer. Since the electric motor running current or voltage corresponding to the input engine operating parameter signal is output using a table lookup method or calculation, the fuel metering pump rotates at an appropriate rotational speed to increase or increase the amount of fuel appropriately. Corrections are made for weight loss.

[Embodiment] FIG. 1 is a longitudinal sectional view showing the configuration of a first embodiment of an electronically controlled carburetor of the present invention, in which reference numeral 101 indicates a vaporizer, and 102
103 is a main intake passage, and 103 is a throttle valve, which is a butterfly type throttle valve in the first embodiment. Reference numeral 104 denotes a venturi, and since it is a fixed venturi in the first embodiment, an inner venturi 105 is disposed at the center. 106 is a float chamber, 1
07 is the main fuel jet, 108 is the venturi 104
109 is a main fuel passage that connects the main fuel jet 107 and the main fuel nozzle 108, 110 is a main air jet, and 111 is a main fuel nozzle that is metered by the main air jet 110. A bleed tube that mixes air as bubbles into the fuel passing through the main fuel passage 109,
7, the main fuel passage 109, the main fuel nozzle 108,
The main air jet 110, the bleed tube 11
1 forms the main fuel system. Reference numeral 112 denotes a low-speed fuel nozzle which opens into the inner wall surface of the main intake passage 102 close to the periphery of the throttle valve 103 which is at the idling opening. A low-speed fuel passage 113 is branched from the main fuel passage 109 and communicates with the low-speed fuel nozzle 112, with a low-speed fuel jet 114 disposed in the middle. 115 is a low-speed air jet, and the air metered by the low-speed air jet 115 is mixed into the fuel flowing in the low-speed fuel passage 118 as bubbles. the low speed fuel passage 113, the low speed fuel jet 114, the low speed fuel nozzle 112,
The low speed air jet 115 forms a low speed fuel system. 116 is an electric motor driven by a computer and whose rotational speed is controlled; 117 is the electric motor 11;
6, which is disposed in the main fuel passage 109 upstream of the branch position of the low-speed fuel passage 113 and downstream of the main fuel jet 107. Incidentally, the venturi is not necessarily required. FIG. 2 is a diagram showing the connection relationship between the electronically controlled carburetor of the present invention, the engine, and the computer, and is designated by the reference numeral 101.
is the carburetor, 103 is the throttle valve, 109 is the main fuel passage, 11
As in FIG. 1, 6 is an electric motor, 117 is a fuel metering pump, 118 is an engine, and 119 is an intake pipe connecting the carburetor 101 and the engine 118.
An intake pipe negative pressure sensor 120 is arranged, 121 is an exhaust pipe of the engine 118, and an 02 sensor 122 that outputs the oxygen concentration in the exhaust gas is arranged.

123 is an intake flow rate sensor arranged on the upstream side of the main intake passage 102 of the carburetor 101, -124 is the throttle valve 103
125 is an engine 1180 rotation speed sensor, 126 is a water temperature sensor that detects the cooling water temperature of the engine 118, and 127 is a starting motor 128 of the engine 118.
129 is an atmospheric pressure sensor, 130 is an atmospheric temperature sensor, 131 is a computer, and 132 is an ignition power signal that turns on the computer 131 when the ignition power is turned on.

Each of the above-mentioned sensors, namely, the intake pipe negative pressure sensor 120.02 sensor 122, the intake flow rate sensor 123, the opening sensor 124 of the throttle valve 103, and the rotational speed sensor 125 of the engine 118
, the water temperature sensor 126, the atmospheric pressure sensor 129, and the atmospheric temperature sensor 130 also use the same reference numerals as those for the respective sensors. The operating conditions of the engine or the environmental conditions under which the engine 118 is operated, which are detected by the above-mentioned sensors, are collectively referred to as engine operating parameters.

The signals output by the intake pipe negative pressure sensor 120, the intake flow rate sensor 123, the opening sensor 124 of the throttle valve 103, and the rotational speed sensor 125 of the engine 118 are basic parameters for determining the fuel flow rate of the engine. Not all of them are always used; for example, any combination of the following is used and input into the computer 131. That is, (a) Engine rotational speed and intake pipe negative pressure (b) Engine rotational speed and intake flow rate (c) Throttle valve opening and engine rotational speed (d) Throttle valve opening and
Engine intake flow rate (E) Throttle valve opening, engine rotation speed, and intake pipe negative pressure (E) Throttle valve opening, engine rotation speed, and intake flow rate. It does not limit how it can be used. The rotation speed of the electric motor 116 that drives the fuel metering pump 117 is determined by the water temperature sensor signal 126, the atmospheric pressure sensor 129, and the atmospheric temperature sensor 1, in addition to the basic engine operating parameters mentioned above.
Corrected fuel flow rate control is performed under the control of the output of a computer which selectively inputs 30.

3 and 4 are block diagrams showing the fuel control of the electronically controlled carburetor of the present invention, with FIG. 3 showing the conventional carburetor section as one block, and FIG. The figure shows the main fuel system and low-speed fuel system separately, and the part indicated by the thick line is the basic configuration of a conventional carburetor (
This is the part added to Fig. 13). Reference numerals in the drawings indicate the same parts as those in FIGS. 1 and 2. This will be compared with the carburetor configuration disclosed in Japanese Patent Application Laid-Open No. 174555/1983, which is shown in block diagrams in FIGS. 14 and 15. Figure 14 shows that in the carburetor disclosed in JP-A-62-174555, a fuel passage in which a computer-controlled auxiliary fuel pump is arranged is provided in parallel with the fuel system of a conventional carburetor. 15 shows a computer-controlled auxiliary fuel system in which the carburetor also disclosed in JP-A-62-174555 is arranged in a fuel passage formed in parallel with the main fuel system and the low-speed fuel system of the conventional carburetor. The pump is an electromagnetic reciprocating piston pump 117a-1 and a suction side check valve 11.
7a-2 and a discharge side check valve 117a-3, an air bleed control valve is provided in the main fuel system, and a fuel passage before the main fuel system and the low-speed fuel system are branched. This indicates that a fuel cut valve is provided that opens the fuel passage to the atmosphere and cuts fuel during deceleration. On the other hand, the electronically controlled carburetor of the present invention has the basic configuration of the carburetor shown in FIG.
09, the computer 131 was installed downstream of the main fuel jet 107 and upstream of the branch point of the low-speed fuel passage 113.
Fuel metering pump 1 driven by electric motor 116 controlled by
17 is additionally placed inline.
The figure shows. Figure 5 shows a second embodiment in which the electronically controlled carburetor of the present invention is applied to a sliding valve type carburetor. Since this is a valve type carburetor, the only difference is that a vent 104 is formed by the end inside the main intake passage 102 of the sliding valve, which is the throttle valve 103. Hereinafter, control examples of each mode of starting/warming up, full-open low speed, acceleration, fuel cut during deceleration, 02 sensor feedback, atmospheric pressure correction, and high output fuel increase correction will be explained using flowcharts.

■ Starting/warming-up mode (Fig. 6) The computer 13 is activated by the ON signal 132 of the ignition system power supply.
1 is turned on, and the computer 131 starts operating (start).

From the water temperature sensor signal 126 and the atmospheric temperature sensor signal 130, the current or voltage value and time range to be applied to the electric motor 116 that drives the fuel metering pump 117 are looked up from a table from the map (step 134).

With the ON signal 127 of the starting motor 128, the electric motor 11
6, the drive signal 133 is outputted (step 135).

The current or voltage value is maintained for a set time (step 136).
.

It is determined whether a complete explosion has occurred based on a sudden change in the rotational speed of the engine 118 or whether the engine rotational speed has reached a threshold value (step 137). If it is determined that the explosion has not occurred completely, the process returns to step 134. When it is determined that the explosion is complete, proceed to the next step.

The current or voltage of the electric motor 116 is looked up from the map from the water temperature sensor signal 126 and the rotational speed sensor signal 125, and the current or voltage is updated (step 138).

Based on the opening sensor signal 124, it is determined whether the throttle valve 103 is at the idling opening (step 13).
9). If the opening is not idling, return to step 138, and if the opening is idling,
Proceed to the blowing step.

The electric motor 116 is stopped and the starting mode is completed (step 140). Transfer to another control.

■ Fully open low speed mode (Fig. 7) Determine whether the opening of the throttle valve 103 is a high opening based on the opening sensor signal 124 (step 141)゜If it is not a high opening, another control is performed and the opening is set to a high opening. If it is determined to be a degree, proceed to the step of kin.

Based on the opening signal 124 and the rotational speed sensor signal 125 of the engine 118, the current or voltage to be applied to the electric motor 116 is determined by table lookup of the map, and the pulsation signal 183 is output (step 142).

Based on the opening sensor signal 124, it is determined whether the opening/closing speed of the throttle valve 103 is equal to or higher than a set value (step 143). If it is less than or equal to the set value, the process returns to step 141 and the above operation is repeated, but if it is greater than or equal to the set value, the mode shifts to acceleration mode.

■ Acceleration mode (Fig. 8) The engine 11B determines whether the opening speed of the throttle valve 103 exceeds the set value based on the opening sensor signal 124.
The rotational speed sensor signal 125 of the engine 118
It is determined whether the rotational speed of is within the set range (step 144). The opening speed of throttle valve 1o3 is below the set value,
When the rotational speed of the engine 118 is outside the set range, the control shifts to another control, and when the speed at which the throttle valve 103 opens is equal to or higher than the set value,
When the rotational speed of engine 11B is within the set range,
Proceed to next step.

Based on the rotation speed of the engine 118 just before acceleration (rotation speed sensor signal 125) and the opening degree of the throttle valve 103 (opening degree sensor signal 124) or the negative pressure in the intake pipe 119 (intake pipe negative pressure sensor signal 120) , determines the fuel increase correction for acceleration, and therefore the current or voltage to be applied to the electric motor 116, by table lookup, and outputs the drive signal 133 to the electric motor 116 (step 145).
.

It is determined whether the opening degree of the throttle valve 103 exceeds the set opening degree based on the opening degree sensor signal 124 (step 146). Throttle valve 1
If the opening degree of 03 does not exceed the set value, step 14
Return to step 4, and if it exceeds, shift to another control.

■ Fuel cut mode during deceleration (Fig. 9) Throttle valve 103
It is determined whether the opening degree is the idling opening degree based on the opening degree sensor signal 124 (step 147). If the opening is not idling, the process moves to another control, and if the opening is idling, the process proceeds to the next step.

The rotation speed of the engine 118 is set to a set value, for example, 200.
It is determined based on the rotation speed sensor signal 125 whether or not the rotation speed exceeds Orpm (step 148). If it does not exceed the limit, it moves to another control, and if it does, it moves to the next step.

A drive signal 133 is output that causes the electric motor 116 to rotate in reverse at the set rotational speed (step 149).

Again, it is determined based on the opening sensor signal 124 whether the opening degree of the throttle valve 103 is equal to or greater than the idling opening degree (
Step 150). If the opening is idling, the process returns to step 148, and if the opening is equal to or higher than idling, the process proceeds to the next step.

The electric motor 116 is stopped (step 151), and the process moves to another control.

■ 02 sensor feedback control (Fig. 10) When the engine 118 is in any mode other than starting/warming up, full-open low speed, acceleration, and fuel cut during deceleration, the rotational speed of the engine 118 and the opening degree of the throttle valve 103 are controlled. is within the set range (in the flowchart of FIG. 10, this is expressed as the operating range in which 02 sensor feedback is performed). The basic setting of the carburetor is set in advance to a leaner side than the stoichiometric mixture ratio, and the fuel metering pump 117 normally rotates in the forward direction so that it can correspond to most modes. Therefore, even if the 02 sensor signal 122 indicates that the air-fuel mixture is rich, if the fuel metering pump 117 is stopped, the air-fuel mixture becomes lean. In addition, 02 sensor signal 122
When indicates that the air-fuel mixture is lean, the throttle valve 103 opening sensor signal 124 and the engine 1180 rotation speed signal 125
From this, the signal 133 that drives the electric motor 116 is looked up in a table to control the rotational speed of the fuel metering pump 117 that corrects the fuel flow rate. In FIG. 10, it is determined whether the engine 118 is in a region where Q2 sensor feedback control is performed (step 152).
). If the area is not in the 02 sensor feedback control area, the process moves to another control, and if it is in the 02 sensor feedback control area, the process proceeds to the next step.

Based on the 02 sensor signal 122, it is determined whether the air-fuel mixture is leaner than the stoichiometric mixture ratio (step 153). If the fuel is not lean, the process goes to step 156, which will be described later, and stops the rotation of the electric motor 116 and therefore the fuel metering pump 117. If the fuel is lean, the process goes to the next step.

Opening sensor signal 124 of throttle valve 103 and engine 118
The rotation speed sensor signal 125 and the signal 133 to the electric motor 116 are table-looked up and output (step 154).

Based on the 02 sensor signal 122, it is determined whether the air-fuel mixture is richer than the stoichiometric mixture ratio (step 155).

If it is not dark, return to step 154; if it is dark, proceed to the next step.

The electric motor 116 and therefore the fuel metering pump 117 are stopped (step 156). Next, the process returns to step 152.

■ Atmospheric pressure correction mode (Fig. 11) It is determined whether the absolute value of the deviation of atmospheric pressure from standard atmospheric pressure is larger than a set value (step 157). When the absolute value of the deviation is smaller than the set value, the electric motor 116 is not driven and the process returns to step 157, and when the absolute value of the deviation is larger than the set value, the process proceeds to the next step.

Table lookup of the absolute value of the rotational speed of the electric motor 116 with respect to the absolute value of the deviation [Step 158]
.

It is determined whether the atmospheric pressure is plus or minus the standard atmospheric pressure (step 159).

When the value is negative, the electric motor 116 (fuel metering pump 117) is rotated in the reverse direction (step 160).

When positive, the electric motor 116 (fuel metering pump 1
17) in the forward direction (step 161). Step 1
Return to 57.

■ High output region fuel increase correction mode (Fig. 12) Outputs the oscillation signal 133Q of the electric motor 116 corresponding to the fuel increase correction amount from the opening sensor signal 124 of the throttle valve 103 and the rotational speed signal 125 of the engine 11B. .

It is determined whether the opening degree of the throttle valve 103 is in the high output region (step 162). If it is not in the high output region, it shifts to another control, and if it is in the high output region, it advances to the next step.

It is determined whether the rotational speed of the engine 118 is in a high output range (step 163). If the engine is not in the high output range, it moves to a full throttle low speed routine, and if it is in the high output range, it moves to the second step.

Opening sensor signal 124 of throttle valve 103 and engine 118
In addition to the rotational speed sensor signal 25, the signal 133 to the electric motor corresponding to the fuel increase correction amount is looked up in a table and output (step 164). Step 16
Return to 2.

It is clear that the operating ranges that do not correspond to the above-mentioned operating modes depend on the inherent flow rate characteristic setting of the carburetor and operate in exactly the same manner as a conventional carburetor, resulting in a complete open loop.

The present invention can be implemented using a small motor using strong magnets such as rare earth magnets.

[Effects of the Invention] By configuring a simple electronically controlled carburetor in which a fuel metering pump operated by an electric motor whose rotational speed is controlled by a cocomputer is arranged in a fuel passage, each of the engine operating states and operations described above can be controlled. Fuel increase/decrease correction can be performed appropriately in response to the environment, similar to an electronically controlled fuel injection system. However, electronically controlled fuel injection systems may stop working at all due to computer failure, making the vehicle unable to drive.

The electronically controlled carburetor of the present invention has the advantage that only the correction element stops functioning, the basic function as a carburetor is maintained, and the vehicle can continue to be driven. Further, since the electronically controlled carburetor of the present invention does not require a choke valve, the length of the carburetor in the direction of the main intake passage can be shortened, which is advantageous in terms of installation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a first embodiment of the electronically controlled carburetor of the present invention, FIG. 2 is a diagram showing the connection relationship between the electronically controlled carburetor of the present invention, an engine and a computer, and FIG. Fig. 4 is a block diagram showing the fuel control of the electronically controlled carburetor of the present invention. Fig. 3 shows the conventional carburetor part as one block, and Fig. 4 shows the main fuel system and The low-speed fuel system and firefly separation are shown. FIG. 5 is a longitudinal cross-sectional view showing the second embodiment of the present invention, and each of the figures from FIG. 6 to FIG. A flowchart showing the routine of each mode of feedback control, atmospheric pressure correction, and high output increase correction, FIG. 13 is a diagram showing an example of the configuration of a conventional carburetor,
14 and 15 are block diagrams showing the fuel system of the carburetor disclosed in Japanese Patent Application Laid-open No. 174555/1983. Explanation of symbols: 101... Electronically controlled carburetor, 102... Main intake passage, 103... Throttle valve, 104
...Venturi, 106...Float chamber, 107...
Main fuel jet, 108... Main fuel nozzle, 109... Main fuel passage 112... Low speed fuel nozzle, 113... Low speed fuel passage, 114... Low speed fuel jet, 116... Electric motor, 117...Fuel metering pump. Applicant Mikuni Makino Kogyo Co., Ltd. Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Procedure amendment written form) July 1, 1985 3. Person making the amendment Relationship to the case Patent applicant address 1018 Kaneko, Oimachi, Ashigarakami-gun, Kanagawa Prefecture, Showa 6
June 28, 2013 (Shipping port) 5. Column 6, “Title of the invention” of the specification subject to amendment, Contents of amendment

Claims (1)

[Claims] The fuel in the float chamber (106) is transferred to the main fuel jet (107).
) and through the main fuel passage (109).
A main fuel system that is supplied from a main fuel nozzle (108) into the main intake passage (102); 113), adjacent to the periphery of the throttle valve (103), which is disposed in the main intake passage downstream of the main fuel nozzle (108), when the throttle valve (103) is at an idling opening. A low-speed fuel nozzle (112) opens on the inner wall surface of the main intake passage (102).
) and a low-velocity fuel system in which fuel is supplied into the main intake passage from the main fuel passage (
109), a fuel metering pump (117) driven by a computer-controlled electric motor (116) is disposed upstream of the branch location of the low-speed fuel passage (113) and downstream of the main fuel jet; , which is driven by output signals from a computer that inputs various engine operating parameter signals, and whose rotational speed is controlled to adjust the fuel flow rate generated by the intake negative pressure generated in the main intake passage (102) according to the operating state of the engine. An electronically controlled vaporizer characterized by correction.