JP2000265928A - Fuel pressure controller in fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain an excessive fuel pressure rise in a fuel chamber including a fuel distribution passage, to damp pulsation pressure in the fuel distributing passage, and to prevent noise generation. SOLUTION: A fuel pressure controller S is constituted of a fuel pressure regulator part R on one side of a housing 1, and a pulsation damper part D on the other side of the housing. In the fuel pressure regulator part R, a first fuel chamber 4 is formed of a first recessed part 1A of the housing and a regulator diaphragm 3, and a pressure chamber S is formed of a first cover 2 and the regulator diaphragm 3. A valve seat 7 of a second passage 8 continuous with 9 fuel pump is opened in the first fuel chamber 4, and the valve seat 7 is opened and closed by a regulator valve element 10. Spring force of a valve element spring 9 and a regulator spring 11 is applied to the regulator valve element 10. In the pulsation damper part D, a second fuel chamber 23 is formed of a third recessed part 1F of the housing 1 and a pulsation diaphragm 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank in which fuel in a fuel tank is pressurized by a fuel pump and supplied to a fuel distribution pipe.
On the other hand, the pressurized fuel is regulated to a predetermined control pressure by a fuel pressure regulator, and the fuel regulated to the predetermined control pressure is injected and supplied toward the engine from a fuel injection valve mounted on a fuel distribution pipe. The present invention relates to a fuel pressure control device in a fuel injection device, and more particularly to control of fuel pressure in a fuel distribution pipe.

[0002]

2. Description of the Related Art Japanese Patent No. 2774728 is a first example of a fuel pressure control device in a conventional fuel injection device. According to this, when the engine is stopped, the valve body 68 disposed in the inlet 64 connected to the fuel pump is provided with a spring compressed in the gas chamber 48. The pressure seat 90 holds the valve seat 84 open. Then, when the engine is started and fuel pressurized from the fuel pump flows into the liquid fuel chamber 46 through the inlet 64 and the valve seat 84, the fuel pressure in the liquid fuel chamber 46 gradually increases, and the bellows 62
The spring 90 is driven by the fuel pressure in the liquid fuel chamber 46.
Is displaced toward the gas chamber 48 while compressing. Then, according to the displacement of the bellows 62 toward the gas chamber 48, the valve valve body 68 is displaced synchronously with the bellows 62 toward the gas chamber 48 by the spring force of the spring 74, and finally the valve body 68 is moved to the valve seat 84. And the flow of fuel from the inlet 64 into the liquid fuel chamber 46 is blocked.
Fuel pressure (A) k increased by the fuel pump added to 4
The predetermined control pressure (B) lower than g / cm ² (for example, 3.5 kg / cm ² ) kg / cm ² (for example, 3 kg / cm ² )
Is maintained. Here, when fuel is consumed from the fuel injector 22 connected to the liquid fuel chamber 46,
The fuel pressure in the liquid fuel chamber 46 is a predetermined control pressure (B) kg
/ Cm ² (3 kg / cm ² ). According to this, the bellows 62 due to the fuel pressure in the liquid fuel chamber 46 is reduced.
The bellows 62 are displaced toward the liquid fuel chamber 46 by the spring force of the spring 90, and the valve body 68
Opens the valve seat 84 again. According to the above, the fuel pressure (A) kg / cm ² (3.
5 kg / cm ² ) of fuel is supplied into the liquid fuel chamber 46, whereby the fuel pressure in the liquid fuel chamber 46 can be returned to the predetermined control pressure (B) kg / cm ² again. As described above, the fuel pressure of the desired predetermined control pressure (B) kg / cm ² can be continuously maintained in the liquid fuel chamber 46 by the opening / closing operation of the valve body 68 with respect to the valve seat 84 as described above. Then, when the temperature of the fuel in the fuel rail 20 rises significantly during a hot soak of the engine, a long continuous low-speed operation, or the like, the fuel in the fuel rail 20 expands, and the volume of the fuel in the fuel rail 20 increases. As it increases, the fuel pressure rises excessively. Here, in this state, when the fuel pressure in the liquid fuel chamber 46 including the fuel rail 20 rises significantly, first, the bellows 62
Displacement toward the gas chamber 48 against the spring force of 0 absorbs an increase in the volume in the liquid fuel chamber 46, and secondly, the valve body 68 moves the valve seat 84 against the spring force of the spring 74. Open and release excessive fuel pressure in the liquid fuel chamber 46 toward the inlet 64. Therefore, occurrence of excessive fuel pressure in the fuel rail 20 including the liquid fuel chamber 46 at the time of hot soaking of the engine or the like is suppressed.

A second example of a fuel pressure control device in a conventional fuel injection device is disclosed in US Pat. No. 5,413,077. According to this, when the engine is stopped, the sphere 74 arranged in the passage 22 connected to the fuel pump holds the seat 85 open by the spring force of the spring 56 contracted in the chamber 54. Then, when the engine is started and the fuel pressurized by the fuel pump flows into the fuel chamber 52 through the passage 22 and the seat 85, the movable wall 40 compresses the spring 56 while the chamber 54 is compressed.
Side, the sphere 74 is moved by the spring force of the spring 76 to the seat 8.
5 is closed. According to the above, the passage 22 is provided in the chamber 54.
(A) kg / cm ² (for example, 3.5
kg / cm ² ), a predetermined control pressure (B) lower than the fuel pressure (A) kg / cm ² by shutting off the supply of
The fuel pressure can be regulated and maintained at kg / cm ² (for example, 3 kg / cm ² ). On the other hand, when the fuel volume in the fuel rail 12 increases significantly and the fuel pressure rises excessively during hot soaking of the engine or the like, the sphere 74 opens the seat 85 against the spring force of the spring 76 and the fuel chamber 52 The excessive fuel pressure inside the fuel rail 12 is released toward the passage 22, thereby suppressing the generation of the excessive fuel pressure in the fuel rail 12.

[0004]

According to the conventional example,
At the time of engine hot soak, etc.
The fuel pressure in the chamber is at a predetermined control pressure (B) kg / cm^Two 
(3kg / cm^Two Excessive fuel pressure exceeding ()) (C) kg /
cm^Two The valve seat opens when the
To release the fuel pressure in the fuel chamber to the primary side fuel inflow passage.
Accurately determine the pressure at which the fuel pressure in the fuel chamber is released
Can not. That is, the regulating valve element is opened to the valve element.
Fuel pressure in the fuel chamber applied as a force on the discharge side (a) kg /
cm^Two And a primary fuel applied to the valve body as a closing-side force
Fuel pressure in the inflow channel (b) kg / cm ^Two Pressure difference (a-
In b), for the first time in the relationship a> b
Regulating valve body against primary spring force
Open the valve seat in the fuel flow path. On the other hand, in the primary fuel inflow channel
Is determined by the discharge pressure of the fuel pump.
The discharge pressure of this fuel pump is a single
Pressure fluctuations due to fluctuations in current value etc.
And between fuel pumps during mass production.
Even so, the discharge pressure fluctuates. That is, the fuel pump
It is extremely difficult to keep the discharge pressure of the pump constant
It is. If the above is described with an example,
The differential pressure of (ab) is 0.3 kg / cm^Two Regulated in
The rate valve opens the valve seat against the spring force of the valve spring.
When set to release, the fuel pressure in the primary fuel inflow passage
Is 3.5kg / cm^Two , The fuel pressure in the fuel chamber
3.8kg / cm^Two And the differential pressure is 0.3 kg /
cm^Two And the regulating valve body opens the valve seat.
The fuel pressure in the primary side fuel inflow passage is 3.6 kg / cm.
^TwoIs changed to 3.9, the fuel pressure in the fuel chamber becomes 3.9.
kg / cm^Two And the differential pressure is 0.3 kg / cm^Two 
And the regulating valve body opens the valve seat. Furthermore, 1
The fuel pressure in the secondary fuel inflow passage is 3.7 kg / cm^Two Strange
The fuel pressure in the fuel chamber is 4.0 kg /
cm^Two And the differential pressure is 0.3 kg / cm^Two Reached
The regulating valve opens the valve seat. As mentioned above,
Fuel pressure in the fuel chamber where the regulating valve opens the valve seat
Opening start pressure cannot be specified accurately.

Further, as described above, the excessive fuel pressure generated in the fuel chamber is released into the primary fuel inflow passage by opening the valve seat by the regulating valve body. A collision of fuel and pressure toward the fuel chamber occurs in the inflow passage. That is, the pressure of the fuel that is pressurized by the fuel pump and flows toward the valve seat and the pressure of the fuel that flows from the fuel chamber toward the primary fuel inflow passage via the valve seat in the primary fuel inflow passage. This causes a vibration in the primary fuel inflow passage, which may cause noise from the fuel pressure regulator and its piping system.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-mentioned problems even when the discharge pressure of the fuel pump fluctuates and the fuel pressure in the primary fuel inflow passage fluctuates. To accurately suppress the fuel pressure in the fuel distribution pipe including the fuel chamber without being affected by pressure fluctuations in the inside. And the generation of noise from the fuel pressure regulator and its piping system. It is a first object of the present invention to provide a fuel pressure control device in a fuel injection device that can be used. Further, when the fuel injection valve closes the fuel injection hole and the supply of fuel is stopped, the extremely large fuel pressure generated in the fuel distribution pipe is effectively attenuated and the pulsating pressure generated in the fuel distribution pipe is reduced. A second object of the present invention is to provide a fuel pressure control device in a fuel injection device that can be effectively attenuated.

[0007]

In order to achieve the above object, a fuel pressure control device in a fuel injection device according to the present invention is configured such that fuel pressurized by a fuel pump is regulated by a fuel pressure regulator to control the fuel pressure. In a fuel injection device in which fuel supplied to a pipe and regulated in pressure is supplied to an engine from a fuel injection valve mounted on a fuel distribution pipe, the fuel pressure control device includes a first flow path opening toward one end. A first recess opening to one side end, a second recess opening to the first recess, a first through-hole communicating the first recess with the first flow path, and A housing formed by a third recess that opens, a second through-hole communicating the third recess with the first flow path, sandwiched between one end of the housing and a first cover covering the housing; Forming a first fuel chamber in the first recess and a first cover; A diaphragm having a second flow path having one end opened to the first fuel chamber through the valve seat and the other end opened to the second recess, and a flow path; A valve body spring disposed in the second flow path of the member for urging a regulating valve body for opening and closing the valve seat toward the valve seat, and a contracted and contracted pressure diaphragm in the pressure chamber to move the regulator diaphragm toward the first fuel chamber side A second fuel chamber is sandwiched between a fuel pressure regulator formed by a biasing regulator spring, the other end of the housing, and a second cover covering the fuel pressure regulator. A pulsation diaphragm in the form of a deep mountain, which forms the air chamber separately with the second cover;
And a pulsation damper portion comprising a damper spring for urging the pulsation diaphragm toward the second fuel chamber. The fuel pressure Akg / cm ² in the second concave portion, which is opened in the fuel distribution passage of the pipe and is pressurized by the fuel pump, is adjusted to a predetermined control pressure Bkg / cm ² by the fuel pressure regulator to be supplied to the first passage. The pulsation pressure generated in the fuel distribution passage is attenuated by the pulsation damper portion while the pulsation pressure generated in the fuel distribution passage is supplied through the holes and the first flow passage. excessive fuel pressure C kg / cm ² that exceeds cm ^2, that it has absorbed is displaced into the atmospheric chamber side against the pulsation diaphragm spring force of the damper spring first It is a feature of the.

The present invention has a second feature in that, in addition to the first feature, the set spring force of the damper spring is smaller than the set spring force of the regulator spring.

[0009]

According to the first aspect, fuel pressurized in the fuel pump ^{(A) kg / cm 2 (} 3.5kg / cm 2), the fuel pressure regulator portion through the second flow path 1 The fuel flows into the fuel chamber, and the fuel in the first fuel chamber displaces the regulator diaphragm toward the pressure chamber against the spring force of the regulator spring. The regulating valve body is pressed by the valve body spring and moves synchronously with the regulator diaphragm, and the regulating valve body closes the valve seat, whereby a constant predetermined control pressure (B) in the first fuel chamber of the fuel pressure regulator section. kg / cm ² (3.0 kg / cm
² ) Adjust the pressure. (B) kg / cm
^The fuel whose pressure has been adjusted to ² is supplied. In the fuel distribution channel,
Pulsating pressure is generated by the continuous opening and closing of the fuel injection valve, and this pulsating pressure is generated by the second pulsation damper.
It is introduced into the fuel chamber and is attenuated and smoothed by the displacement of the pulsation diaphragm. Also, when the fuel temperature in the fuel distribution path rises and the fuel pressure rises excessively, the increased fuel pressure acts on the pulsation diaphragm of the pulsation damper, and the pulsation diaphragm is pressed while pressing the damper spring. It is largely displaced toward the atmosphere chamber, thereby suppressing an excessive rise in fuel pressure. Further, when the fuel injection valve rapidly closes the injection hole, a further large fuel pressure is instantaneously generated in the fuel distribution passage, and the pressure increase is increased by the pulsation diaphragm of the pulsation damper portion as described above. The fuel is absorbed and a further increase in fuel pressure in the fuel distribution passage is suppressed.

According to the second feature, it is possible to regulate the pressure to a predetermined control pressure (B) kg / cm ² by the regulator diaphragm of the fuel pressure regulator. In addition, the pulsation diaphragm of the pulsation damper part can effectively attenuate the pulsating pressure generated in the fuel distribution passage, and when the fuel pressure in the fuel distribution passage greatly exceeds a predetermined control pressure. In addition, when the fuel pressure in the fuel distribution passage rises extremely greatly during the rest when the fuel injection valve closes the injection hole, the increase in the fuel pressure can be effectively suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel pressure control device S in a fuel injection device according to the present invention will be described below with reference to the drawings. The fuel pressure control device S is formed by a fuel pressure regulator R and a pulsation damper D. Reference numeral 1 denotes a housing, which includes the following. 1A is a first flow path opening toward one end (left side in the figure), and 1B is a first flow path opening toward one side end 1C (upward in the figure).
The recess is a recess, and 1D is a second recess recessed further downward in the figure than the bottom 1E of the first recess 1B.
1F is a third concave portion that opens toward the other end 1G (downward in the figure). The first recess 1B and the first flow path 1A are connected via a first through hole 1H, and the third recess 1B is connected to the first recess 1B.
F and the first flow path 1A are connected via the second through hole 1J. The outer circumference of the first flow path 1A has a cylindrical shape.

A fuel pressure regulator R is formed on one side of the housing 1 as follows. 2 is
The first cover covers the opening of the first recess 1B, and a regulator diaphragm 3 is arranged and sandwiched between one side end 1C and the first cover 2. According to the above description, one side of the regulator diaphragm 3 and the first side of the housing 1
The first fuel chamber 4 is formed by the recess 1 </ b> B, and the pressure chamber 5 is separately formed by the other side surface of the regulator diaphragm 3 and the first cover 2. Reference numeral 6 denotes a flow path member. Inside the flow path member, there is provided a second flow path 8 whose upper side is opened to the upper end via a valve seat 7 and is opened toward the lower end. Regulated valve element 1 pressed by valve element spring 9 to open and close valve seat 7 and close valve seat 7
0 is placed. The flow path member 6 including the regulating valve body 10 and the valve body spring 9 is press-fitted and arranged in the second concave portion 1D of the housing 1. At this time, the upper part of the second flow path 8 is provided via the valve seat It opens in the first fuel chamber 4 and opens in the second recess 1D below. That is, the second concave portion 1D
Opens into the first fuel chamber 4 via the second flow path 8 and the valve seat 7. Reference numeral 11 denotes a regulator spring contracted into the pressure chamber 5, one end of which is engaged with the bottom of the first cover 2, and the other end of which is engaged with a retainer which is integrally attached to the regulator diaphragm 3, which will be described later. Is done. The retainer 12 is integrally attached to the regulator diaphragm 3, and has a cup for locking the regulator spring 11 on the pressure chamber 5 side of the regulator diaphragm 3, and is provided on the first fuel chamber 4 side of the diaphragm 3. Has a locking flange portion, and further has a regulating rod 12A having a rod shape directed downward from the locking flange portion.
Are formed to protrude. The regulating rod 12A is arranged facing the regulating valve body 10. When the valve body spring 9 and the regulator spring 11 are set, the spring force of the regulator spring 11 is stronger than that of the valve body spring 9. According to this, any pressure is applied to the pressure chamber 5 and the first fuel chamber 4. In a state in which the regulating valve 12A is not provided, the regulating rod 12A separates the regulator valve element 10 from the valve seat 7, and holds the second flow path 8 open in the first fuel chamber 4.
2A is a pressure introduction hole formed in the first cover 2.

A pulsation damper D is formed on the other side of the housing 1 as follows. 20 is
A pulsation diaphragm 2 having a deep mountain shape is formed between the other side end 1G and the second cover 20. The pulsation diaphragm 2 has an air hole 20A covering the opening of the third recess 1F.
1 is arranged and fixed. According to the above, the atmosphere chamber 22 is formed by one side surface of the pulsation diaphragm 21 and the second cover 20, and the second fuel chamber 23 is formed separately by the other side surface of the pulsation diaphragm 21 and the third recess 1 </ b> F of the housing 1. Is done. The second fuel chamber 23 is connected to the first flow path 1A through the second through hole 1J. 24
Is a damper spring contracted into the atmosphere chamber 22, one end of which is locked to the bottom of the second cover 20, and the other end of which is connected to the pulsation diaphragm 2 via a retainer 25.
1 locked on. The set spring force of the regulator spring 11 of the fuel pressure regulator R and the set spring force of the damper spring 24 of the pulsation damper D are defined by the set spring force of the damper spring 24. It is set to be smaller.

The fuel distribution pipe F is provided with a fuel distribution passage 30 which is opened toward the right end in the longitudinal direction, and has a plurality of fuel injection valve insertion holes 31 which cross the longitudinal axis. .

A fuel pressure control device S having a fuel pressure regulator R and a pulsation damper D is attached to the fuel distribution pipe F as follows. A known rear end of the fuel injection valve J is inserted and arranged in the fuel injection valve insertion hole 31 of the fuel distribution pipe F. Next, a cylindrical outer peripheral portion 1 formed on the outer periphery of the first flow passage 1A of the housing 1 of the fuel pressure control device S is provided in a fuel distribution passage 30 opened at the right end of the fuel distribution pipe F.
P is inserted, and the housing 1 is fixed to the fuel distribution pipe F in this state. The means for fixing the housing 1 to the fuel distribution pipe F, the outer peripheral portion 1P of the housing 1 and the fuel distribution passage 30
The sealing means for airtightness is omitted. According to the above description, the fuel distribution passage 30 is connected to the first fuel chamber 4 of the fuel pressure regulator R through the first passage 1A and the first through hole 1H, and the first passage 1A and the second passage 1H. Through the hole 1J, it is communicated with the second fuel chamber 23 of the pulsation damper part D.

A discharge side passage of a fuel pump (not shown) is connected to an opening 1S opened in the second recess 1D of the housing 1.

Next, the operation will be described. Institutional luck
In the stopped state where the rotation has been completed, the fuel
Fuel is stored in the distribution path 30, and in such a state,
The regulating valve body 10 of the fuel pressure regulator R is a valve.
The seat 7 is held open. Next, the operation of the engine will be described.
Then, the fuel in the fuel tank (not shown) is
Therefore (A) kg / cm^Two (For example, 3.5 kg / cm
^Two ), And the pressurized fuel is supplied to the openings 1S,
The fuel pressure level is controlled via the second recess 1D, the second flow path 8 and the valve seat 7.
The fuel is introduced into the first fuel chamber 4 of the ruler portion R. more than
According to the regulation diaphragm including the regulating rod 12A,
3 is a pressure against the spring force of the regulator spring 11.
It is displaced to the force chamber 5 side (upward in the figure).
According to the description, the regulating valve body 10 is a spring of the valve body spring 9.
The valve seat 7 is displaced to the side where the valve seat 7 is closed by force, and
And the flow of fuel into the first fuel chamber 4 is restricted.
As a result, the fuel pressure in the first fuel chamber 4 is reduced to a predetermined control pressure.
(B) kg / cm^Two (For example, 3 kg / cm^Two ) With pressure regulation
Wear. Then, the fuel adjusted to the predetermined control pressure,
The fuel flows through the first fuel chamber 4, the first through hole 1H, and the first flow path 1A.
The fuel is supplied into the fuel distribution path 30 of the distribution pipe F, and this fuel is
The fuel is supplied to the engine through the fuel injection valve J. On the other hand,
According to the consumption of fuel from the fuel injection valve J, the fuel distribution passage 30
The fuel pressure in the first fuel chamber 4 including the pressure is set to a predetermined control pressure of 3 k.
g / cm^Two From 2.8kg / cm ^Two But also
Therefore, according to the decrease in the fuel pressure in the first fuel chamber 4,
Regulator diaphragm 3 is a regulator spring
11 corresponds to a decrease in the fuel pressure due to the spring force of the first fuel.
Is displaced toward the chamber 4 (downward in the figure), and the regulating rod 12A
The regulating valve body 10 is pressed to open the valve seat 7 again.
To the side. According to the above, the second
3.5 kg / cm of the pressure in the two flow paths 8^Two Fuel pressure
Is introduced into the first fuel chamber 4.
As a result, the fuel pressure in the first fuel chamber 4 again becomes the predetermined control pressure.
3kg / cm of force^Two Is held. Thereafter, when the engine is running
In the above, the above operation is continuously performed, and the fuel distribution pipe F
Of the predetermined control pressure (B) kg /
cm^Two Is supplied.

On the other hand, during operation of the engine,
Within 0, a pulsating pressure occurs. This is the fuel distribution path 30
Is caused by the fuel injection valve J continuously opening and closing the valve hole of the valve and the pumping action of the fuel pump. Here, the fuel distribution passage 30 is provided in the second fuel chamber 23 of the pulsation damper section D via the first flow passage 1A and the second through hole 1J.
The fuel pressure inside acts. As described above, the pulsating pressure generated in the fuel distribution passage 30 acts on the pulsation diaphragm 21 via the first flow passage 1A, the second through hole 1J, and the second fuel chamber 23. The pulsation diaphragm 21 receiving the pressure compresses the damper spring 24 in accordance with the magnitude of the pulsating pressure and displaces the damper spring 24 toward the atmosphere chamber 22 (downward in the figure), thereby attenuating the pulsating pressure. At this time, it should be noted that the set spring force of the damper spring 24 of the pulsation damper portion D is made weaker than the set spring force of the regulator spring 11 of the fuel pressure regulator portion R. Effectively attenuating the pulsating pressure in the interior.

Even in the case of the regulator diaphragm 3 of the fuel pressure regulator portion R, it cannot be denied that the pulsation pressure is somewhat attenuated due to the characteristics of the diaphragm.

When the engine is suddenly decelerated, the fuel injection from the fuel injection valve J may be temporarily stopped, whereby the valve hole of the valve is temporarily closed and the fuel distribution passage 30 is stopped. the control pressure (B) kg / cm ² to more than a very large consisting fuel pressure (C) kg / cm ² there may temporarily occur in the inside. Here, in the present invention, such an extremely large fuel pressure is applied to the pulsation damper portion D.
As a result, the unnecessary fuel is prevented from leaking into the intake pipe from the fuel injection valve J immediately and effectively. That is, when the fuel pressure in the fuel distribution passage 30 exceeds the predetermined control pressure (B) kg / cm ² and reaches (C) kg / cm ² , the pulsation diaphragm 21 of the pulsation damper unit D moves to the second fuel chamber. When the pressure rise in the inside 23 is sensed, it is largely displaced toward the atmosphere chamber 22 against the spring force of the damper spring 24, and the pressure rise is immediately absorbed.
What should be particularly noted here is that the shape of the pulsation diaphragm 21 is formed into a deep mountain shape, and the set spring force of the damper spring 24 is controlled by the regulator spring 1.
1 when the pulsation diaphragm 21 can be displaced immediately when a large fuel pressure (C) kg / cm ² is generated. That is, the diaphragm 21 can be largely displaced toward the atmosphere chamber 22. Accordingly, the fuel pressure in the fuel distribution passage 30 including the first fuel chamber 4 and the second fuel chamber 23 is prevented from rising above the predetermined control pressure (B) kg / cm ^2, thereby regulating the fuel. The valve body 10 keeps the valve seat 7 closed and holds the valve seat 7 from the valve seat 7 toward the inside of the second flow path 8.
The fuel pressure in the fuel chamber 4 does not escape. According to the above, during the rapid deceleration operation of the engine, the fuel pressure in the fuel distribution passage 30 does not greatly increase beyond the predetermined control pressure (B) kg / cm ² controlled by the fuel pressure regulator R. Therefore, fuel does not leak from the fuel injection valve J into the intake pipe. Further, even when the fuel pressure in the fuel distribution passage 30 rises above the predetermined control pressure, the regulating valve body 10 does not open the valve seat 7 and the fuel pressure in the first fuel chamber 4 increases. Since there is no escape to the second flow path 8 and the second concave portion 1D via the seat 7, pressure collision in the second flow path 8 and the second concave portion 1D is eliminated, whereby the fuel pressure control device S and its piping The system no longer generates noise.

Further, when the engine is in a hot soak operation or at a low speed operation, the fuel distribution pipe F is heated and the fuel distribution passage 3 is heated.
The fuel temperature in the fuel distribution line 30 greatly increases, the fuel volume in the fuel distribution passage 30 greatly increases, and the fuel pressure excessively increases as compared with the predetermined control pressure (B) kg / cm ² . Here, in the present invention, the excessive fuel pressure is applied to the pulsation diaphragm 21 of the pulsation damper section D.
The fuel is immediately and effectively absorbed by the fuel injection valve J, and unnecessary fuel leaks from the fuel injection valve J into the intake pipe. The generation of noise from the fuel pressure control device S and its piping system is suppressed. This is for the same reason as described above. Note that the setting of the fuel pressure used in the above description is a numerical value used for facilitating the description, and is not limited thereto.

[0022]

As described above, according to the fuel pressure control device in the fuel injection device according to the present invention, the fuel having the fuel pressure (A) kg / cm ² boosted by the fuel pump is prescribed by the fuel pressure regulator. The control pressure (B) is controlled to be kg / cm ² and supplied into the fuel distribution passage, and the fuel having the predetermined control pressure is injected and supplied to the engine via the fuel injection valve. Property can be maintained favorably. Further, the pulsation pressure generated in the fuel distribution passage is attenuated by the pulsation diaphragm of the pulsation damper, which is effective in improving the fuel controllability of the fuel injection valve. In particular, according to the pulsation diaphragm having a deep mountain shape, the fuel pressure in the fuel distribution passage including the fuel chamber is excessively high (C) kg / cm ² exceeding the predetermined control pressure (B) kg / cm ^2. When the pressure increased to ² , the pulsation diaphragm was further displaced toward the atmosphere chamber against the spring force of the damper spring, so that the excessive fuel pressure increase can be immediately absorbed and returned to the predetermined control pressure. As a result, unnecessary fuel does not leak from the fuel injection valve into the intake pipe, and the engine performance can be maintained satisfactorily. The absorption of the excessive fuel pressure (C) kg / cm ² is performed by the relationship between the fuel pressure in the fuel chamber including the fuel distribution passage and the spring force of the damper spring. The fuel pressure in the passage and the second recess is not involved at all, so that the excessive fuel pressure can be absorbed and suppressed very accurately. In addition, when the excessive fuel pressure is absorbed by the pulsation diaphragm, the regulating valve body closes and holds the valve seat when the excessive fuel pressure is generated. According to this, the first fuel chamber passes through the valve seat through the valve seat. The backflow of the fuel pressure into the second flow passage and the second recess is suppressed, and the collision of the fuel in the flow passage is eliminated, whereby the vibration in the flow passage is suppressed, and the fuel pressure regulator and its piping system The noise was reduced. Furthermore, since a single housing is used in common for the housing of the fuel pressure regulator and the housing of the pulsation damper, the number of parts can be reduced, which is effective in reducing the manufacturing cost. Further, when the fuel pressure control device is mounted on the fuel distribution pipe, a single housing may be assembled, so that the assembling work time can be reduced. Further, at the time of maintenance, the maintenance work of the fuel pressure regulator unit and the pulsation damper unit can be performed by removing the fuel pressure control device, thereby greatly improving the maintainability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of an embodiment of a fuel pressure control device in a fuel injection device according to the present invention.

[Explanation of symbols]

 S Fuel pressure control device R Fuel pressure regulator part D Pulsation damper part F Fuel distribution pipe 1 Housing 1A First flow path 3 Regulator diaphragm 4 First fuel chamber 5 Pressure chamber 7 Valve seat 8 Second flow path 9 Valve spring 10 Regulator valve 11 Regulator spring 21 Pulsation diaphragm 22 Atmosphere chamber 23 Second fuel chamber 24 Damper spring 30 Fuel distribution path

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02M 55/02 340 F02M 55/02 340E 350 350E 350P

Claims (2)

[Claims] 1. A fuel pressurized by a fuel pump is regulated by a fuel pressure regulator and supplied to a fuel distribution pipe, and the regulated fuel is directed from a fuel injection valve mounted on the fuel distribution pipe to an engine. The fuel pressure control device S includes a first passage 1A opening toward one end, a first recess 1B opening toward one side end 1C, and an opening in the first recess 1B. The second concave portion 1 </ b> D
A first through hole 1H that communicates the recess 1B with the first flow path 1A,
A housing 1 formed by a third recess 1F opening toward the other side end 1G, a second through hole 1J communicating the third recess 1F and the first flow path 1A, and one side end 1 of the housing 1
C, and a regulator diaphragm 3 sandwiched between the first cover 2 covering the first diaphragm 2 and forming the first fuel chamber 4 in the first recess 1B and separately forming the pressure chamber 5 in the first cover 2; A flow path member 6 having a second flow path 8 having one end opened to the first fuel chamber 4 via the valve seat 7 and the other end opened to the second recess 1D; A valve spring 9 is disposed in the passage 8 and urges a regulating valve body 10 for opening and closing the valve seat 7 toward the valve seat 7. The third recess 1F is sandwiched between a fuel pressure regulator R formed by a regulator spring 11 biasing toward the chamber 4, the other end 1G of the housing 1, and a second cover 20 covering the same. To form the second fuel chamber 23 and the second cover 20 A pulsation diaphragm 21 having a deep mountain shape that forms a partition into the atmosphere chamber 22 by means of a diaphragm, and a damper spring 24 that is contracted within the atmosphere chamber 22 and urges the pulsation diaphragm 21 toward the second fuel chamber 23. And a pulsation damper section D, which connects the second recess 1D to the discharge path of the fuel pump, opens the first flow path 1A into the fuel distribution path 30 of the fuel distribution pipe F, and raises the pressure by the fuel pump. Second concave portion 1
The fuel pressure A kg / cm ² in D, first by applying a predetermined control pressure Bkg / cm ² two adjustment by the fuel pressure regulator unit R 1
The fuel is supplied into the fuel distribution passage 30 through the through hole 1H and the first flow passage 1A, and the pulsation pressure generated in the fuel distribution passage 30 is attenuated by the pulsation damper portion D. The predetermined control pressure Bkg / cm ²
A fuel pressure control device for a fuel injection device, wherein an excessive fuel pressure Ckg / cm ² exceeding the above is absorbed by displacing the pulsation diaphragm 21 toward the atmosphere chamber 22 against the spring force of the damper spring 24. 2. The fuel pressure control device according to claim 1, wherein the set spring force of the damper spring is smaller than the set spring force of the regulator spring.