JPS58128445A - Variable fuel pressure type carbureter - Google Patents

Abstract

PURPOSE:To obtain optimum fuel pressure in accordance with running conditions, by operating a fuel pressure regulator in accordance with the displacement of an accelerator and as well by correcting the fuel pressure by means of a series of culculations in consideration with the conditions of the engine and the ambient air, so that the optimum fuel pressure previously set is obtained. CONSTITUTION:The outputs of a fuel pressure sensor 11 for detecting the pressure of fuel flow, an ambient air condition sensor 12 and an engine condition sensor 13 for engine speed, cooling water temperature, throttle opening degree, etc., are delivered to an MPU (microprocessor unit) 10 for controlling a fuel pressure regulator 7 by a control signal obtained by carrying out a series of calcurations. Further, at this stage, an accelerator control signal is delivered to an air metering system 14 for changing the volume of intake air in accordance with the above-mentioned accelerator control signal, and the output signal of the system is delivered to an air detecting system 101 in the MPU for obtaining the volume of intake air. Further, an appropriate fuel volume is obtained in a fuel control system 102 in accordance with the air volume in consideration with engine parameters, etc., thereby a fuel pressure control system 15 is controlled with the use of the output of the control system 102.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable fuel pressure carburetor, and particularly to a variable fuel pressure carburetor that can set the fuel pressure applied to a jet to an optimum value in accordance with engine conditions, atmospheric conditions, and the like.

In general, a float type, an overflow type, a diaslam type, etc. are usually adopted for the carburetor of an internal combustion engine in order to maintain the fuel pressure applied to the jet at a specified value. Therefore, fuel is injected from the jet according to the negative pressure of the venturi due to the amount of intake air, and although there may be no problem in the operating state where the air-fuel ratio can be covered by this, during acceleration etc. , had to be compensated for by an accelerator pump, for example.

However, the air-fuel ratio by the carburetor is not only affected by the speed state, but also the atmospheric conditions at the time of driving, the height difference of the driving position, the engine operating condition, and above all, cracking/king, water temperature, rotation speed, throttle opening, boost. It is also subtly affected by pressure, exhaust temperature, etc.

The present invention has been made to solve the above problems, and aims to provide a variable fuel pressure carburetor that can adjust the fuel pressure applied to the jet to an optimal value under any driving condition. .

The present invention uses a microprocessor to calculate the fuel pressure measured by the fuel pressure sensor, the atmospheric conditions during driving, the engine operating conditions, etc., and adjusts the fuel pressure regulator to obtain the optimum fuel pressure. be.

Examples will be described below with reference to the drawings.

FIG. 1 is a fuel system diagram of a variable fuel pressure carburetor according to the present invention;
FIG. 2 is a block diagram of an embodiment of a variable fuel pressure carburetor.
FIG. 3 is a block diagram of another embodiment, FIG. 4 is a block diagram of the calculation system, and FIG. 5 is a flowchart for calculation processing.

In FIG. 1, 2 is an IU suction pipe, 2 is a venturi, and 3 is a throttle valve. 4 is a main nozzle, and 5 is a low-speed nozzle, each of which is connected to a fuel pressure regulator 7 via a jet 6. Reference numeral 8 denotes a fuel pump which pumps up fuel from the fuel tank 9, and branches one side to the jet 6 side and the other side to the fuel tank 9 side via the fuel pressure regulator 7. Therefore, the fuel pump 8 has a structure in which the required amount of fuel pumped up (p-) flows to the nozzle side, and the remainder flows back to the fuel tank 9 side as a return amount.

Next, the fuel pressure adjusting means will be explained with respect to the fuel system diagram having the above configuration.

FIG. 2 is a block diagram of an embodiment of a variable fuel pressure carburetor. Reference numerals 7 to 9 in the figure correspond to those in FIG.

Reference numeral 10 denotes a microprocessor (hereinafter referred to as ■kan), which executes a series of arithmetic operations taking into account various conditions according to a pre-built-in program. A fuel pressure sensor 11 detects the fuel pressure in the fuel flow path and inputs it to the MPU 10 at any time. Reference numeral 12 denotes an atmospheric condition sensor that detects, for example, temperature and atmospheric pressure, and inputs the detected information to the MPU 10. Reference numeral 13 is an engine condition sensor that detects operating parameters such as engine speed, water temperature, boost pressure, throttle opening, exhaust temperature, and cranking.
Enter in U10. Therefore, the MPU 10 executes a series of arithmetic operations taking into account the above conditions and operates the fuel pressure regulator 7 to obtain an appropriate fuel pressure.

The calculation system will be explained with reference to FIG. In FIG. 4, reference numeral 14 denotes an air measuring system, which transmits an operating signal from the accelerator directly to the tough fly pulp via a throttle wire to change the amount of intake air.

101 is an air detection system, for example, engine speed,
Engine conditions such as throttle opening and suction pipe negative pressure are detected and the amount of air is estimated or directly measured using an air flow sensor. Reference numeral 102 denotes a fuel control system, which calculates the appropriate fuel amount QruEt=Qair ""'- from the air amount.
In this case, as described above, the engine parameters and other input conditions are taken into consideration.

The calculation program will be explained with reference to the flowchart shown in FIG. FIG. 5(a) is a fuel pressure adjustment program.

First, in step 516, a driving mode determination process is performed. This is, so to speak, engine state determination, as described above. In 5tep17, the air amount is estimated and directly measured by the fail flow sensor. In 5tep 18, the above 5tep 17
The basic supply fuel is calculated according to the air amount. In 5tep19, the corrected fuel amount is calculated taking into account the operating mode, atmospheric conditions, etc. in 5tep16. At 5tep 20, an input string to the fuel pressure adjustment actuator is calculated according to the correction amount, and at 5tep 20,
Return to p. 16.

FIG. 5(b) is a flowchart for checking the operating status at any time, for example, periodically or irregularly, and for use in making corrections in the flowchart shown in FIG. 5(a). It is a flowchart for periodically changing the output of the input string to the fuel pressure adjustment actuator, for example, and determining the optimum value according to the operating condition. Moreover, the programs shown in FIGS. 5(a), 5(b), and 5(c) do not exist independently, but are of course executed in parallel by interrupts.

FIG. 3 is a block diagram of another embodiment.

Reference numerals 7 to 10, 12 and 13 in the figure correspond to those in FIG. 21 is a phototransistor, and 22 is a light source. Therefore, the fuel pressure in the fuel flow path is transmitted to the phototransistor 21 using see-through light from the light source 22, and the fuel pressure is detected through the difference in height of the fuel surface.
The other configurations and calculation programs are the same as those in the embodiment described above.

As explained above, according to the present invention, the air metering system such as the butterfly valve is directly operated by the operation signal from the accelerator, and at the same time, the appropriate amount of fuel is calculated according to the amount of air, and when adjusting the fuel pressure, the engine Since the configuration is such that the calculation is performed by a microprocessor that takes into account the state and atmospheric conditions, it is possible to obtain an appropriate fuel pressure that takes various conditions into account, as well as to compensate for the lack of performance of the carburetor alone by adjusting the fuel pressure. We can provide equipment.

[Brief explanation of drawings]

FIG. 1 is a fuel system diagram of a variable fuel pressure carburetor according to the present invention;
Fig. 2 is a block diagram of one embodiment of variable fuel pressure vaporization, Fig. 3 is a block diagram of another embodiment, Fig. 4 is a block diagram of the calculation system, and Fig. 5 is the calculation l...intake pipe.
2... Venturi 3... Throttle valve 4... Main nozzle 5... Low speed nozzle
6...Jet 7...Fuel pressure regulator
8...Fuel pump 9...Fuel tank
10...Microprocessor 11...Fuel pressure sensor 12...Atmospheric condition sensor 13
...Engine condition sensor 14...Air measurement system 15...Fuel pressure adjustment system 101...Air detection system 102...Fuel control system Patent applicant: Mikuni Industries Co., Ltd. Representative Patent attorney: Norio Ishii

Claims (2)

[Claims] (1) In a variable fuel pressure carburetor that can maintain the fuel pressure of an internal combustion engine at an optimal value at any time, accelerator displacement is detected by changes in air volume, the fuel pressure regulator is operated by the output from a microprocessor, and the engine condition and atmospheric conditions are A variable fuel pressure carburetor is characterized in that the fuel pressure detected by a fuel pressure sensor is corrected through a series of arithmetic processing that takes into account the following, and the fuel pressure is set to a preset optimum fuel pressure value. (2) The fuel pressure variable carburetor according to claim 1, wherein the fuel pressure sensor is comprised of a light source and a phototransistor.