JPH1026063A - Pressure regulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure regulator suitable for accurate control of a fine fuel amount from a fuel injection valve. SOLUTION: A fuel chamber 7 comprises a housing body 1; and one side 4A of a small diaphragm 4, and a fuel inflow passage 8 and a fuel return passage 9 are opened in a fuel chamber 7. A negative pressure chamber 12 consists of a cover housing 3 and the other side 5B of a large diaphragm 5, and a negative pressure introduction passage 13 is opened in the negative chamber 12. An atmosphere chamber 10 is located between the fuel chamber 7 and the negative pressure chamber 12 and consists of one side 5A of the large diaphragm 5, the other side 4B of a small diaphragm 4, and an intermediate housing 2. The large diaphragm 5 and the small diaphragm 4 are integrally intercoupled through a coupling lever 6. A valve part 14 to open and close a fuel return passage 9 is arranged on the one side 4A side of the small diaphragm 4. A spring 15 contracted in the negative pressure chamber 12 energizes the large diaphragm 5 to the fuel chamber 7 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure regulator for use in a fuel injection device of an internal combustion engine, and the pressure regulator controls the amount of fuel injected from a fuel injection valve to the energization time output from an ECU. The fuel pressure in the fuel pipe connected to the fuel injection valve to make it proportional to the pressure in the intake pipe where the fuel injection valve opens,
This is a pressure adjusting device that maintains a constant differential pressure.

[0002]

2. Description of the Related Art In a conventional pressure regulator, a housing is divided into a negative pressure chamber and a fuel chamber by a diaphragm, and a fuel inflow passage is opened in the fuel chamber, and the housing is opened and closed by a valve portion which moves integrally with the diaphragm. The fuel return passage is opened, and a spring for pressing the diaphragm toward the fuel chamber is contracted in the negative pressure chamber, and a negative pressure introduction passage communicating with the inside of the intake pipe is opened.

[0003]

According to such a conventional pressure regulator, when the fuel pressure in the fuel pipe (hereinafter referred to as fuel pressure) acts on the fuel chamber of the pressure regulator through the fuel inflow passage, the fuel pressure becomes effective by the diaphragm. Acts on the area and generates a force corresponding to (fuel pressure × effective area of the diaphragm) to act in the direction of contracting the spring. When the fuel pressure applied to the fuel chamber is larger than the set fuel pressure value, the diaphragm moves to the negative pressure chamber and opens the fuel return passage largely. If the fuel pressure applied to the fuel chamber is smaller than the set fuel pressure value, the diaphragm moves to the negative pressure chamber side and holds the fuel return passage in a small opening state. Therefore, the fuel pressure in the fuel pipe is constant at the value of (spring set load / diaphragm effective area).

On the other hand, during operation of the engine, a negative pressure in an intake pipe in which a fuel injection valve is opened is introduced into a negative pressure chamber of a pressure regulator through a negative pressure introduction passage. Is reduced corresponding to (negative pressure × effective area of diaphragm). According to the above, the fuel pressure = [spring set load− (negative pressure × effective area of diaphragm)] / effective area of diaphragm = (spring set load / effective area of diaphragm) −negative pressure. The pressure difference from the fuel pressure can be kept constant.

On the other hand, in recent years, in order to improve fuel economy and reduce harmful exhaust gas components, it is necessary to control the fuel supply amount during idling operation of the engine to a very small amount. Here, as described above, in the fuel injection device using the conventional pressure regulator that maintains the differential pressure between the negative pressure in the intake pipe and the fuel pressure constant, the fuel pressure is kept relatively high because the fuel pressure is kept relatively high. The energization time for the injection valve has become extremely short, making it difficult to accurately control a minute amount of fuel.

[0006] The pressure regulator according to the present invention has been made in view of the above-mentioned problem, and when a throttle valve is operated at a low opening degree, such as during idling of an engine, a fuel amount smaller than that of a fuel injection valve can be extremely accurately determined. An object is to provide a pressure regulator suitable for control.

[0007]

According to the present invention, there is provided a pressure regulator, comprising: a housing;
A fuel chamber facing one side of the small-diameter diaphragm and having a fuel inflow passage and a fuel return passage open, a negative pressure chamber facing the other side of the large-diameter diaphragm and having a negative-pressure introduction path opened, and a small-diameter diaphragm other. The side face and one side face of the large-diameter diaphragm are divided into an air chamber in which an air introduction passage is opened, and the large-diameter diaphragm and the small-diameter diaphragm are arranged to face each other with a gap therebetween and integrally formed by a connecting rod. A valve for opening and closing the fuel return passage is arranged on one side of the small-diameter diaphragm, and a spring for urging the other side of the large-diameter diaphragm toward the fuel chamber is reduced in the negative pressure chamber. It is characterized by.

[0008]

[Function] The effective pressure receiving area of the diaphragm (large diameter diaphragm) to which the negative pressure in the intake pipe acts is larger than the effective pressure receiving area of the diaphragm (small diameter diaphragm) to which the fuel pressure acts. Thus, the fuel pressure can be kept low. According to this, the energization time to the fuel injection valve is lengthened and the minute fuel amount is controlled, so that accurate fuel control can be performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the pressure regulator according to the present invention will be described below with reference to FIG. H is a housing, and a housing main body 1, an intermediate housing 2, and a cover housing 3 are arranged in contact with each other from below. 4
Are the other end surface 1A of the housing body 1 and the intermediate housing 2
Is a small-diameter diaphragm sandwiched between the first end face 2A and the second end face 2A. Reference numeral 5 denotes a large-diameter diaphragm sandwiched between the other end surface 2B of the intermediate housing 2 and one end surface 3A of the cover housing 3. The large-diameter diaphragm 5 and the small-diameter diaphragm 4 are arranged with a gap therebetween, and a connecting rod 6 is provided.
Are connected integrally.

According to the above description, the fuel chamber 7 is formed by the one side surface 4A of the small diameter diaphragm 4 and the concave portion of the housing body 1, and the fuel chamber 7 communicates a fuel pump (not shown) with a fuel distribution pipe (not shown). A fuel inflow passage 8 connected to the flow path or the fuel distribution pipe is opened, and a fuel return passage 9 connected to a fuel source (not shown) is opened.

The lower opening of the recess provided in the intermediate housing 2 is closed by the other side surface 4B of the small-diameter diaphragm 4 and the upper opening is closed by one side surface 5A of the large-diameter diaphragm 5. The atmosphere chamber 10 is formed by the other side surface 4B of the small diameter diaphragm 4 and one side surface 5A of the large diameter diaphragm 5.
An air introduction passage 11 communicating with the atmosphere is opened in the atmosphere chamber 10, whereby the atmosphere chamber 10 is maintained at atmospheric pressure. A negative pressure chamber 12 is formed by the other side surface 5B of the large diameter diaphragm 5 and the cover housing 3 covering the other side surface 5B. The negative pressure chamber 12 has a negative pressure in an intake pipe in which a fuel injection valve (not shown) opens. Pressure is introduced via a negative pressure introduction channel 13.

On the other hand, a valve portion 14 for controlling opening and closing of the fuel return passage 9 is integrally disposed on one side surface 4A of the small diameter diaphragm 4. In this example, the valve portion 14 is disposed at a lower end of the connecting rod 6. A spring 15 is contracted in the negative pressure chamber 12, and one end of the spring 15 is locked to the other side surface 5B of the large-diameter diaphragm 5, thereby forming the large-diameter diaphragm 5 and the small-diameter diaphragm. Numeral 4 is pressed and urged downward, and the valve portion 14 closes the fuel return passage 9.

Next, the operation will be described. When the fuel pressure in the fuel pipe acts on the fuel chamber 7 of the pressure regulator through the fuel inflow passage 8, this fuel pressure acts on the effective area of the small diameter diaphragm 4, and corresponds to (fuel pressure × effective area of the small diameter diaphragm 4). Spring 1
5 acts in the direction of shrinking. On the other hand, during the operation of the engine, the negative pressure in the intake pipe in which the fuel injection valve opens through the negative pressure introducing passage 13 is introduced into the negative pressure chamber 12 of the pressure regulator. Spring 1
5 is reduced corresponding to (negative pressure × effective area of large diameter diaphragm 5).

According to the above, fuel pressure = [set load of spring 15− (negative pressure × effective area of large-diameter diaphragm 5)] / effective area of small-diameter diaphragm 4 = spring 1
5, the set load / the effective area of the small diameter diaphragm 4− (the negative pressure × the effective area of the large diameter diaphragm 5 / the effective area of the small diameter diaphragm 4), so that the fuel pressure can be reduced. For example, if the effective area of the large-diameter diaphragm 5 is twice as large as the effective area of the small-diameter diaphragm 4, the fuel pressure can be reduced to twice the negative pressure.

According to the above, when supplying a small amount of fuel from the fuel injection valve, such as during idling operation of the engine, the fuel pressure can be reduced. Thus, it is possible to control minute fuel very accurately. On the other hand, during high-speed operation of the engine, the negative pressure in the intake pipe is small (small negative pressure means that it is close to atmospheric pressure). The state is maintained, and the atomization characteristics of the fuel injected from the fuel injection valve are maintained well, so that good engine performance can be exhibited.
In addition, the control of the fuel pressure by the pressure regulator controls the spring characteristics of the spring and the effective area of the large-diameter diaphragm,
Various fuel pressure characteristics can be obtained by selecting the effective area of the small diameter diaphragm, and the fuel controllability of the fuel injection valve can be greatly improved.

[0016]

As described above, according to the pressure regulator according to the present invention, the small-diameter diaphragm is disposed facing the fuel chamber, and the large-diameter diaphragm is disposed facing the negative pressure chamber, and the diaphragms are operated synchronously. Due to such mechanical connection, it is possible to provide a pressure regulator which is suitable for precisely controlling minute fuel particularly and for providing a fuel injection device having excellent atomization characteristics during high-speed operation. The fuel pressure depends on the spring characteristics of the spring,
It can be obtained freely by setting the effective area of each diaphragm, thereby improving the fuel controllability of the fuel injection valve.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a pressure regulator according to the present invention.

[Explanation of symbols]

 H housing 4 small diameter diaphragm 5 large diameter diaphragm 6 connecting rod 7 fuel chamber 8 fuel inflow path 9 fuel return path 10 atmosphere chamber 11 atmosphere introduction path 12 negative pressure chamber 15 spring

Claims (1)

[Claims] A housing (H) faces one side surface (4A) of the small-diameter diaphragm (4), and a fuel inflow passage (8) and a fuel return passage (9).
And a negative pressure chamber 12 facing the other side surface 5B of the large diameter diaphragm 5 and having a negative pressure introduction passage 13 opened.
And an air chamber 10 facing the other side 4B of the small-diameter diaphragm 4 and one side 5A of the large-diameter diaphragm 5 and having an open air introduction passage 11. The large-diameter diaphragm 5 and the small-diameter diaphragm 4 are separated by a gap. A valve portion 14 for opening and closing the fuel return passage 9 is disposed on one side 4A side of the small-diameter diaphragm 4 and is integrally connected by a connecting rod 6. A pressure regulator, wherein a spring 15 for urging the other side surface 5B of the large diameter diaphragm 5 toward the fuel chamber 7 is reduced.