JPS6385247A - vaporizer - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel flow rate measuring device in a floatless carburetor that controls the fuel flow rate using a fuel flow rate control means.

[Prior Art and Problems to be Solved by the Invention] Conventionally, this type of vaporizer has been proposed by the present applicant, for example, as shown in FIGS. 4 to 10. In the figure, 1 is an intake passage, 2 is a throttle valve, 3 is a nozzle arranged in the venturi part, 4 is a metering jet,
5 is a fuel passage for feeding fuel from the fuel tank 6 to the nozzle 3 by the fuel pump 7; 8 is disposed in the middle of the fuel passage 5 between the fuel pump 7 and the metering jet 4, and is used to open and close the passage 5; Reference numeral 9 indicates a liquid level detection passage whose lower end is connected to a portion of the fuel passage 5 between the fuel flow control means 8 and the metering jet 4 and whose upper end communicates with the atmosphere; A liquid level sensor 11 disposed in the liquid level detection passage 9 is disposed between the sludge pump 7 of the fuel passage 5 and the fuel flow rate control means 8, and is arranged in the fuel passage 5 to detect the liquid level even if the output of the fuel pump 7 fluctuates. This is a fuel pressure regulator that can always apply fuel pressure to the fuel flow rate control means 8. The liquid level sensor 10 is of a so-called transparent type as shown in FIG.
When the liquid level 9a is below the set height, the light emitted from the light emitting element 10a passes through the fuel passage 9 as it is, so the electromotive force generated in the light receiving element 10b is large; Result detection circuit (Figure 9)
The sensor output becomes small as shown in FIG. (FIG. 6). Also, when a float 12 made of an opaque material is floated on the liquid surface 9a as shown in FIG. Since the electromotive force of the light-receiving element 10b becomes almost zero, the sensor output becomes large as shown in FIG. 8.In addition, in the detection circuit shown in FIG. When the electromotive force of 10b is large, the input voltage applied to the (-) terminal of the operational amplifier C0P1 becomes high, and the output of the operational amplifier C0PI becomes rLJ. Conversely, when the output of the light receiving element tab is small, the output of the operational amplifier COP + becomes rHJ.Furthermore, FIG. 9 shows a control circuit for forming a reference liquid level in the fuel passage 9. When the output is lower than the reference voltage, the output of the operational amplifier COP z becomes rHJ, which makes the transistor Tr conductive, thereby opening the fuel flow rate control means 8 to increase the fuel flow rate and raise the liquid level. When the height of the liquid level 9a is higher than the set height, that is, when the output of the liquid level sensor 10 is higher than the reference voltage,
The output of the operational amplifier COP becomes rLJ, which shuts off the transistor Tr, thereby closing the fuel flow rate control means 8 and reducing the fuel flow rate, thereby lowering the liquid level 9a.

In this way, by turning on or cutting off the transistor Tr based on the output of the liquid level sensor 10, the valve opening rate of the fuel flow rate control means 8 is controlled, thereby increasing the liquid level 9a.
A reference liquid level is formed where the height of the fuel is maintained at a set height.4 The present invention provides a vaporizer whose fuel flow rate can be measured without using a special fuel flow meter in such a conventional floatless carburetor. The purpose is to provide equipment.

[Means and operations for solving the problem] In the carburetor according to the present invention, as shown in FIG. A gap is formed between the valve opening rate and the valve opening rate to calculate the valve rate.In other words, since the pressure difference in the fuel passage before and after the fuel flow rate control means 8 is kept constant, the flow rate of the supplied fuel is corresponds to the valve opening rate of the fuel flow rate control means 8, and therefore, the fuel flow rate can be measured based on the valve opening rate.

〔Example〕

Hereinafter, one embodiment of the vaporizer according to the present invention will be described based on FIGS. 2 and 3 and with reference to FIGS. 4 to 9. FIG. 2 shows a control circuit for forming a reference liquid level. In the figure, 13 is a frequency dividing circuit that divides the frequency of a rotation signal consisting of a pulse train, and 14 is a frequency dividing circuit to which the pulse signal from the frequency dividing circuit 13 and the output signal of the operational amplifier C0P2 are input, and the fuel flow rate control means 8 is RS flip-flop capable of sending a drive pulse signal to the transistor Tr to be driven; 15;
is a valve opening rate calculation routine for calculating the valve opening rate of the fuel flow rate control means 8 based on the drive pulse signal, and is programmed as shown in FIG.

This control circuit controls the fuel flow rate of the carburetor as shown in FIGS. 4 to 9.

Since the vaporizer of the present invention is constructed as described above, when the height of the liquid level 9a is below the set height, the output of the liquid level sensor 10 becomes rHJ (see Fig. 6), and the operational amplifier The H level signal of COP z is sent to the flip-flop 14.
The flip-flop 14 sends out a drive pulse signal to the transistor Tr. At this time, the valve opening rate calculation routine 15 causes a timer to start at the same time as the pulse signal rises, and as the liquid level 9a reaches the set height, the operational amplifier COP Z goes to the L level and the signal is sent to the transistor Tr. The time until the drive pulse signal falls, that is, the fuel flow rate; the time during which the crevice 1 means 8 is open is stored in the register 1. Furthermore, the sum of the time until the next drive pulse signal is sent to the transistor Tr, that is, the time stored in the register 1, and the subsequent time during which the fuel flow rate control means 8 is closed is stored in the register 2. It will be done. Next, the times stored in both registers 1 and 2 are compared, thereby calculating the ratio of time during which the fuel flow control means 8 is open during a certain period of time, that is, the valve opening rate. Since the pressure difference before and after the fuel flow control means 8 in the fuel passage 5 is always kept constant,
The fuel flow rate in the passage 5 can be determined using the calculated valve opening ratio.

〔Effect of the invention〕

As described above, in the carburetor according to the present invention, the flow rate of the supplied fuel can be easily and precisely measured without using a special flowmeter, so the structure of peripheral devices including the carburetor itself can be simplified. In addition, it has excellent practical advantages such as being able to accurately grasp the state of the air-fuel mixture to be supplied based on the determined fuel flow rate, and contributing to proper engine operation.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a control circuit and valve opening rate calculation routine for a carburetor according to the present invention, FIG. 2 is a circuit diagram showing an embodiment of the control circuit according to the present invention, and FIG. Flowcharts showing the structure of the valve rate calculation routine, FIGS. 4 to 1
Figure O shows a conventional floatless vaporizer, Figure 4 is a sectional view showing the overall structure, Figures 5 and 6 are a sectional view of the liquid level sensor and a graph showing output changes, and Figure 7. and FIG. 8 are cross-sectional views of modified examples of the liquid level sensor and graphs showing changes in the output thereof, FIG. 9 is a detection circuit diagram attached to the liquid level sensor, and FIG. 10 is a control circuit diagram. DESCRIPTION OF SYMBOLS 1... Intake passage, 3... Nozzle, 4... Metering jet, 5... Fuel passage, 7... Fuel pump, 8... Fuel flow rate control means, 9 ...Liquid level detection passage, 10...Liquid level sensor, 11...
regulator, 130. ...Frequency divider circuit, 14...Flip-flop, 15...Valve opening rate calculation routine. Figure 25 Off figure 3 and 6 Figure 8 years old

Claims (1)

[Claims] A fuel flow control means disposed in the middle of the fuel passage between the fuel pump and the metering jet, and a liquid level detecting means connected to a portion of the fuel passage between the fuel flow control means and the metering jet. A liquid level sensor installed in the passage,
In a carburetor comprising a control circuit that drives the fuel flow rate control means according to an output from the liquid level sensor to form a reference liquid level, the fuel flow rate control means is calculated based on a drive signal for the fuel flow rate control means. A carburetor characterized in that the flow rate of fuel in the fuel passage can be measured based on the valve opening rate of the fuel flow rate control means.