JPH01151729A - Auxiliary fuel feed device for engine - Google Patents

Abstract

PURPOSE:To perform proper control of a fuel flow rate through simple and low-cost constitution, by a method wherein a control valve electromagnetically driven according to the running state of an engine and a regulating valve driven by means of a fuel pressure are positioned in juxtaposition, and a regulating valve is driven by means of a differential pressure between the outlet pressures of valves. CONSTITUTION:In a vaporizer 1, an auxiliary fuel passage 5 is connected to an intake air passage 4 having a venturi 2 and a throttle valve 3, and a fuel pump 6, a pressure regulator 7, and a control valve 8 are situated, in order named, in the auxiliary passage 5. An increase fuel passage 10 is branched from the auxiliary fuel passage 5 and connected to an intake air passage 4, and a regulating valve 11 is situated in the increase fuel passage 10. In this case, the control valve 8 is controlled by means of an electronic type control circuit 13. Meanwhile, the regulating valve 11 is driven by means of a differential pressure between an inlet pressure of the regulating valve and that of the control valve 8. The control valve 8 is opened and closed in a duty ratio exceeding a given value, and when the outlet output is increased to a value higher than a given value, the regulating valve 11 is opened.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an auxiliary fuel supply device for increasing the amount of fuel supplied to an engine, and is mainly used for low-temperature starting of automobile engines. Ru.

(Conventional technology) In the carburetor that supplies fuel to the engine.

It has been considered to provide an auxiliary fuel passage with an electromagnetically driven on-off valve in place of a choke mechanism, idle-up mechanism, acceleration mechanism, etc.
0, Utility Model Publication No. 62-2284) 0 It is also widely known that in a fuel injection system that supplies fuel to an engine, a separate fuel injection valve is provided to supply fuel during cold start.

(Problems to be Solved by the Invention) The on-off valve installed in the auxiliary fuel passage of the carburetor disclosed in each of the above-mentioned publications is set to the open position by a command from an electronic control circuit into which the engine operating state is input. Or, since the valve is simply fixed at either the closed position, it is not possible to increase the amount of fuel appropriately depending on the state of the carrot.

Also, what is the appropriate amount of fuel to increase when a normal automobile engine starts at -200?

It takes about 10 J/L from cranking to complete detonation, and about 0.81/L after complete detonation. Therefore, in fuel injection systems, electromagnetically driven fuel control valves, which can control a maximum flow rate up to 6 times the minimum flow rate currently provided, cannot handle this. Equipped with an injection valve. especially.

If such a fuel injection valve is installed separately in a single φ point injection system, it is possible to handle the wide range of fuel flow rate changes required by a supercharged engine, but it is necessary to install two expensive fuel injection valves. Therefore, it is economically disadvantageous. Furthermore, in both single-point and multi-point injection systems, it is necessary to drive the regular fuel injection valve for fuel control when increasing the amount of fuel, which inevitably makes the control system complicated.

In view of these circumstances, the present invention aims to appropriately control a wide range of fuel flow rates with a simple control system that combines - electromagnetically driven control valves with a regulating valve that is driven by fuel pressure. This invention was invented with the object of providing an auxiliary fuel supply system for an engine that can provide the following.

(Means for Solving the Problems) The present invention provides an auxiliary fuel passage having a fuel pump and an electromagnetically driven control valve and opening into an intake passage.

The increase fuel passage has a regulating valve driven by fuel pressure and is open to the intake passage, and an electronic control circuit that sends a drive signal of a duty ratio according to the engine operating state to the control valve. is branched from the auxiliary fuel passage between the fuel pump and the control valve.

The regulating valve is driven by a differential pressure between its outlet pressure and the outlet pressure of the control valve, and is opened when the control valve is opened and closed at a duty ratio of a set value or more and the outlet pressure becomes a predetermined value or more. This is a means to solve the above problems.

(Function) When the control valve is fixed at the closed position, the regulating valve is also closed. - When the control valve starts opening/closing, fuel is injected into the intake passage through the auxiliary fuel passage according to its duty ratio. As the duty ratio increases, the outlet pressure of the control valve gradually becomes higher, and when the differential pressure between the control valve and the outlet pressure of the regulating valve exceeds a certain value, the regulating valve opens.

The opening degree of the regulating valve gradually changes depending on the differential pressure, and reaches its maximum opening degree when the control valve is fixed at the open position.

(Example) The present invention will be implemented in a vaporizer and the proportionality will be explained based on the drawings.

Bench area of carburetor 1 2. Intake passage 4 with throttle 9 valves 3t
The raw nozzle, idle boat, and slow port (not shown) are opened, and Kouyu i! It is exactly the same as before that the main fuel and low-speed fuel are supplied through the fuel passages leading from the r chamber to these.

A passage provided separately from the fuel supply passage leading from the fuel tank to the constant oil level chamber, or a passage branched from the fuel pump downstream side of the fuel supply passage, is connected to the intake passage 4 between the bench area 2 and the throttle valve 3. This passage is open and forms an auxiliary fuel passage 5. The auxiliary fuel passage 5 includes a dedicated fuel pump 6 in the case of the above-mentioned independent passage, and a fuel pump 6 which also serves as the fuel pump of the fuel supply passage in the case of the above-mentioned branched passage, and applies fuel pressure to the discharge side thereof. A constant pressure regulator 7 and an electromagnetically driven control valve 8 are provided in this order.

(9) An increase fuel passage 1O is provided between the pressure regulator 7 and the control valve 8, branching from the auxiliary fuel passage 5, and opening and connecting to the intake passage 4 between the bench area 2 and the throttle valve 3. , this passage 10 has a regulating valve U that changes the opening degree steplessly. Furthermore, the openings of these auxiliary fuel passages 5 and 10 to the intake passage 4 are provided with jets 9 and 12 that regulate the amount of fuel jetted out.
It is equipped with

Reference numeral 13 is an electronic control circuit such as a combiator installed in a car that monitors air-fuel ratio and other control commands, and inputs engine operating status parameters such as throttle valve opening, engine temperature, engine rotation speed, and suction pipe negative pressure. Then, a drive signal consisting of a pulse wave with a predetermined duty ratio is sent to the control valve 8.

Regulating valve ■ is driven by fuel pressure.

That is, in the embodiment shown in FIG. 1, the working chamber which applies the force in the valve opening direction within the two chambers partitioned by the diaphragm 14 to which the regulating valve U is fixed is connected to the auxiliary fuel passage 5 on the downstream side of the control valve 8. is set up. The other chamber is partitioned by the diaphragm 14 and applies a force in the valve closing direction, and is installed in the middle of the increase fuel passage IO to form the outlet chamber 17 of the regulating valve 11 and to close the valve. It has 16 springs built-in.

The fuel pressurized by the fuel pump 6 and adjusted to a constant pressure by the pressure regulator 7 is supplied to the control valve 8. The flow rate is controlled by the regulating valve H, and the air is ejected from the jet 9.12 into the intake passage 4.
When the control valve 8 is fixed at the closed position, no fuel is introduced into the working chamber 15 on the downstream side, so the spring force of the valve closing spring 16 also fixes the regulating valve (2) at the closed position.

When the control valve 8 starts its opening/closing operation in response to a drive signal sent from the electronic control circuit port, fuel at a flow rate corresponding to the duty ratio is ejected into the intake passage 4 through the auxiliary fuel passage 5, and the fuel in the working chamber 9 is injected. The pressure and the fuel flow rate from the jet 9 vary depending on the power ratio as shown in curves P1 and 3 in FIG. Further, when the fuel pressure in the second working chamber t overcomes the spring force of the valve closing spring 16, the regulating valve n opens.

Fuel at a flow rate corresponding to the opening degree is ejected into the intake passage 4 through the increase fuel passage 10. At this time, the fuel pressure in the outlet chamber 17 acts on the diaphragm 14 as a valve closing force, so the regulating valve (2) does not open suddenly, and the fuel pressure in the outlet chamber 17 and the fuel flow rate from the jet 12 The fuel flow rate injected into the air intake passage 4, which changes almost in proportion to the duty ratio in the region of duty ratio higher than the setting, as shown in the Pt curve and C curve in Figure 3, is the Figure 3 curve that is the sum of B and C mentioned above. , the control valve 8 is fixed at the open position, so that the maximum flow rate occurs when the regulating valve (2) reaches its maximum opening.

By changing the spring characteristics of the valve-closing spring 16, it is possible to change the opening degree of the regulating valve 11 for the same duty ratio of the control valve 8 or change the timing at which the regulating valve 11 starts opening.

According to this configuration, when the engine is started at a low temperature, the control valve 8 is fixed at the open position or opened and closed at a large duty ratio to perform cranking, and when a complete explosion occurs, the duty ratio of the control valve 8 is suddenly reduced. By doing.

By appropriately increasing the amount of fuel, reliable starting and stable warm-up can be achieved. Also.

By opening and closing the control valve 8 at an appropriate duty ratio, it is possible to appropriately increase the amount of fuel even during idle up, acceleration, and high load operation.

In the embodiment shown in FIG.
The diaphragm 19° forms an atmospheric chamber 21, and the working chamber 15 applies fuel pressure to the first diaphragm 19, which has a large effective area, and an outlet chamber 17 with a built-in valve closing spring 16. The structure is such that fuel pressure is applied to the second diaphragm which has a small effective area.

According to this embodiment, the regulating valve 1 responds to the pressure increase in the 2 working chambers 15.
1 opens with a small duty ratio of the ratio control valve 6.

Note that the present invention can be applied to a single-point type or even a multi-point type fuel injection system, and in these cases, a regulating valve U is added to the control valve 8 that functions as a regular fuel injection valve.
It is composed of the following.

(Effects of the Invention) According to the present invention, a control valve that opens and closes using a drive signal of the next duty ratio according to the engine operating state and a regulating valve that opens and closes based on fuel pressure are provided in parallel, and the regulating valve is connected to the outlet of the control valve. Since the valve is configured to open when the differential pressure between the pressure and the outlet pressure of the control valve exceeds a certain value, the control valve opens in a region where the duty ratio of the control valve is large and the outlet pressure is high. Therefore, the fuel flow rate can be changed extremely greatly in response to changes in the duty ratio.

Therefore, an inexpensive and simple control system using - electromagnetically driven control valves can appropriately control the fuel flow rate over a wide range, and ensure that the engine can be started at low temperatures and warmed up in a reliable and stable manner. .

[Brief explanation of the drawing]

1 and 2 are configuration diagrams showing different embodiments of the present invention, and FIG. 3 is a diagram showing changes in fuel pressure and fuel flow rate with respect to the duty ratio of the control valve. 4...Intake passage, 5...Auxiliary fuel passage. 6...Fuel pump, 8...Control valve, 10...Increase fuel passage, 11...Adjustment valve, 13...Electronic type Control circuit, 15...
...Working chamber, 17...Exit chamber.

Claims (1)

[Claims] An auxiliary fuel passage (5) that has a fuel pump (6) and an electromagnetically driven control valve (8) and is open to the intake passage (4), and an intake passage (5) that has a regulating valve (11) driven by fuel pressure. 4), and an electronic control circuit (13) that sends a drive signal with a duty ratio according to the engine operating state to the control valve (8).
0) is branched from the auxiliary fuel passage (5) between the fuel pump (6) and the control valve (8), and the regulating valve (11) is connected to the outlet pressure of the control valve (8). The control valve (8) is driven by the pressure difference between the outlet pressure and the control valve (8), and is opened and closed at a duty ratio of a set value or more, and is opened when the outlet pressure exceeds a predetermined value. Engine auxiliary fuel supply system.