JPS58144657A - Electronically controlled carburetor - Google Patents

Abstract

PURPOSE:To obtain a more proper air-fuel ratio, by separating a control system for an air control valve and a control system for a fuel control valve from each other, and controlling the air control valve to correct the pressure difference between the venturi pressure and a required setting pressure. CONSTITUTION:An air control valve 2 is designed to be moved vertically by turning a screw shaft 12 by a driving means such as a servomotor, while a fuel control valve is so designed that the amount of fuel supplied from a float chamber 5 to a fuel outlet port 10 is controlled by a solenoid valve 13. The air control valve controls a servomotor 11 to correct the deviation between a required setting pressure and the venturi vacuum that is increased with increasing of the opening of a throttle valve 3. As for fuel control, fuel supply rate is controlled by pre-calculating the basic duty-ratio of the solenoid valve 13 and correcting the duty-ratio according to the operational mode of an engine and the conditions of the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically controlled carburetor, in particular to an engine over the entire operating range (
Second, it relates to an electronically controlled carburetor that can obtain an appropriate air-fuel ratio.

General: It is well known that a carburetor for an internal combustion engine utilizes a 4q airflow from a venturi and is configured to inject and flocculate fuel using the negative pressure. Both when there is little air flow at low speed loads and when there is a lot of air flow at high speed loads,
In both cases, the fuel and air must be mixed uniformly (two-way mixture), and the injected fuel must be four-folded. However, in order to promote the formation of air and mix uniformly with the air, a higher air flow rate is required. A variable venturi type carburetor is used to maintain the air flow rate constant when the amount of intake air changes depending on the operating state.

A conventional variable venturi type carburetor will be explained with reference to FIG. In FIG. 1, 1 is a suction pipe, and 2 air cleaners (not shown) are connected to each other, through which suction air is introduced as shown by the arrows in the figure. , has a venturi structure, moving up and down like a piston as shown by the arrows in the figure. 4 is a float chamber, inside which is provided a float 5, which floats in accordance with the up and down movement of the fuel surface 6. 7 is a float chamber. Since the arm is attached integrally with the float 5 and moves in accordance with the vertical movement of the float 5, the needle pulp 8 moves up and down, injecting an appropriate amount of fuel each time, and adjusting the fuel level by balancing with the float buoyancy. 6 is formed in the float chamber 4. A jet needle 9 is integrally formed on the lower surface of the air control pulp 2, and is used to change the opening area of the fuel discharge port 10 in accordance with the vertical movement of the air control pulp 2 (2). , is configured to inject fuel according to the amount of intake air to achieve an appropriate air-fuel ratio.

In addition, although drawing (2) is not shown explicitly, a piston spring is inserted in the air control pulp 2, and normally the rising force due to the differential pressure 42 between the negative pressure of the venturi and the internal pressure of the air control pulp, and the air It is fixed at a position where the control pulp's own weight and the descending force of the hihistone spring are balanced.

In the conventional carburetor having the above configuration, since the air control pulp 2 and the jet needle 9 are integrated, the control of the air-fuel mixture is uniquely determined according to the vertical movement of the air control pulp 2. This has the disadvantage that it is not possible to obtain a finely tuned air-fuel ratio.

The present invention has been made in order to solve the above-mentioned drawbacks, and it is an object of the present invention to provide an electronically controlled carburetor that can obtain an appropriate arbitrary air-fuel ratio over the entire operating range.

In the present invention, the control systems for the air control pulp and the fuel control valve are separated into separate units, and the air control pulp is controlled to correct the differential pressure between the venturi pressure and the required set pressure. The fuel control valve is controlled according to engine conditions and atmospheric conditions to obtain a more appropriate air-fuel ratio.

Examples will be described below with reference to the drawings. Fig. 2 is a configuration diagram of an embodiment of an electronically controlled vaporizer according to the present invention, Fig. 3 is a control block diagram, Fig. 4 is a flow chart for arithmetic processing, and Fig. 5 is an electronically controlled vaporizer according to the present invention. In FIG. 2, which is a diagram showing the configuration of another embodiment, the reference numerals 1 to 8 and 10 in the figure correspond to FIG. The air control pulp 2 is moved up and down so as to correct the venturi pressure at the fuel discharge port 10 position to the required set pressure.At this time, the air control pulp 2 is made to move up and down minutely according to the pitch of the threaded shaft 12. , or directly move the air control pulp 2 up and down with a linear stepping motor, etc.1.
3 is a solenoid pulp that controls the amount of fuel from the float chamber 5; 14 is an air bypass, and 15 is an air bypass adjustment screw, which finely adjusts the amount of air when the engine is idling. Although not shown in the figure, a tapered round rod-shaped needle may be provided at the position shown in Figure 1 in order to improve fuel atomization.

The operation of the electronically controlled carburetor having the above configuration, which is not specifically designed for fuel metering, will now be described briefly.

First of all, when running the engine at idle, adjust the throttle and C-lube 3.
Since the circuit is almost closed, the amount of intake air is small. Therefore, in order to increase the amount of air taken in during idling (combining the venturi pressure with the required set pressure), the air control pulp 2 is lowered to increase the flow rate. In this case, the amount of air is Therefore, it is finely adjusted.In this state (2), gradually tighten the throttle valve 3 (
When the opening is increased to 2 degrees, the amount of intake air increases by A corrective control is provided by opening the control pulp.In this way, the venturi pressure is maintained at a constant pressure.

On the other hand, regarding fuel supply, the basic duty ratio of the solenoid pulp 13 is calculated in advance according to the engine conditions, and the amount of supply to the 21-drunette is controlled based on this, and the duty ratio is modified according to the atmospheric conditions and operation mode. It operates to do so.

This will be explained in more detail with reference to the control block diagram in FIG. In the figure, the signal from the accelerator is transmitted directly to the throttle valve via a wire, and is introduced into the electronically controlled carburetor together with the control signal from the microprocessor (hereinafter referred to as MPU) to the air control pulp. Of course, a control signal to the solenoid pulp is also introduced at this time.

Therefore, the air-fuel mixture is drawn into the engine, and torque is generated by the operation of the engine. Therefore, the pressure is kept constant,
Fuel is ejected from the fuel discharge port according to the basic duty ratio. The air control pulp position and fuel discharge port pressure are controlled by two MPUs from the electronically controlled carburetor. Further, engine parameters such as rotational speed, engine temperature (or cooling water temperature), intake pipe internal pressure, throttle valve opening, etc. are input from the engine, as well as atmospheric conditions such as temperature, atmospheric pressure, etc., respectively. Among these, the basic duty ratio of the solenoid pulp is calculated using the two-rotation speed IW1 suction pipe internal pressure and throttle valve opening, and the remaining inputs are used to perform acceleration increase correction, lateral start operation increase correction,
A cold increase correction, a deceleration correction, an altitude correction, an intake temperature correction, etc. are performed. The output signal to the air control pulp 2 is basically generated to maintain the fuel discharge port pressure constant.

The flowchart shown in Figure 4 (2) will explain the calculation program. Figure 4 shows the main routine; 41 is for branching to the motor drive side and the condition calculation side; (Note: This value of 10m sec is provisional. Considering matching with the engine, it is usually 10~1 msec.)
00m5l2) Therefore, the 10m5e
If it is within c, the process moves to 5tep 42, where a driving mode determination process is performed. This is when the engine stops,
This is the determination of idle link, acceleration, deceleration, cranking, etc. , 3tep 43 (In step 2, the intake air amount measurement process is performed. In other words, the intake air amount is calculated from the throttle opening, the intake pipe internal pressure, and the engine rotation speed, or direct asthma measurement is performed using an air flow sensor. 5tep
At 44, basic duty ratio calculation processing is performed,
The duty ratio of the solenoid pulp is calculated according to the above-mentioned intake air amount so as to obtain an appropriate mixing ratio. 5tep
In No. 45, duty ratio correction processing is performed according to the driving mode, and the manual power under each of the above conditions (=acceleration increase,
Correction processing such as increasing the amount of warm air is performed. In step 46, duty ratio correction processing is performed according to the environment.
Corrections based on intake air temperature, atmospheric pressure, etc. are added to the processing results.

One power, 5tep 41 i two, 10m5ec l
If it is repeated twice, it moves to 5tep 47, where the fuel discharge port; the deviation between the two required K sheets constant pressure and the actual measured value is calculated,
If there is a deviation, in 5tep 48 an output sequence to the motor is calculated so that the deviation becomes zero =ttr, and in the next 5tep 49, the output to the motor is derived. That is, at 10m5ec@, the air control valve operates to maintain the fuel discharge port pressure at a constant value.

Moreover, FIG. 4(b) is a subroutine, and 5tep5
At step 0, sampling processing of analog data such as operating conditions is performed, and at step 51, output processing to the solenoid is performed.

Note that the above subroutine interrupts the process shown in FIG. 4 (m1) every time the ignition signal is input. FIG. 5 is a block diagram of another embodiment of the electronically controlled carburetor according to the present invention. 1.3 to 8.10.13 to 1
5 corresponds to FIG. 2 (2). 16 is an air control pulp of a rotating type. 17 is a rotary stepping motor driven by, for example, a belt 18. Except for the structure and drive method of the air control pulp, this structure and operation are exactly the same as those shown in FIG. 2, and the calculation program is also the same.

As explained above, according to the present invention, the control system for the air control pulp and the fuel control valve is divided into 1 parts, and the air control pulp is operated to obtain a certain pressure of the venturi, and the control system for the fuel control valve is operated to obtain a certain pressure of the venturi. Since the configuration is configured to add corrections that take into account the correction amount, it is possible to provide an electronically controlled carburetor that not only is easy to control but also provides an ideal air-fuel ratio over the entire operating range.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional flexible venturi type carburetor, Figure 2
FIG. 3 is a control block diagram, and FIG. 4 is a flowchart for process 4, in which ial is the main routine and ial is the main routine, is a subroutine, and FIG. 5 is a fake diagram of another embodiment of an electronically controlled carburetor according to the present invention. l...di nail, 2...air control valve 1, uh...throttle valve,
4...Float chamber,)...Float,
6...Oil (8), 7...Float
Arm, 8... Needle valve 9... Jet needle, 10... Fuel discharge port, 11... Yaho motor, 12... Screw shaft, 13... Solenoid valve, 14... Air binox , 15...Air bypass adjustment screw, 16...Rotary air control valve 17...Rotary stepping motor, 18...Belt Patent applicant Norio Ishii, agent of Mikuni Kogyo Ajishiki Company, patent attorney

Claims (2)

[Claims] (1) An air control valve located upstream of the throttle valve is created according to the intake air amount of the engine, and the air control valve is installed in an electronically controlled carburetor that maintains the venturi pressure in the intake pipe at a constant value and maintains an appropriate air-fuel ratio. A first control system that operates to open and close and a second control system that changes the amount of fuel discharged are provided separately and separated from each other.
The second control system controls the venturi pressure to be maintained at a constant value in all engine operating ranges, and the second control system controls the fuel amount in consideration of engine conditions and atmospheric conditions. vessel. (2) Air control valve is rotating IRI! 2. An electronically controlled carburetor according to claim 1, wherein the electronically controlled carburetor is operated from the outside via a belt or the like.