JPH0942099A - Fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply device having good maintainability by automatically removing and discharging water contained in fuel. SOLUTION: A water separating vessel 30 is arranged in the halfway of a fuel supply passage 28, connected to a pump housing 2 and integrally formed. A water cohesive filter 31 is contained in a water separating chamber 30a. Fuel drawn up to the water separating vessel 30 from a fuel tank 40 by a low pressure pump 41, because specific gravity of water is larger than a component of fuel contained in fuel, deposits water in a bottom part of the water separating chamber 30a. A water discharge passage 33 communicates with the water separating chamber 30a, also with a fuel delivery passage 14 through a check valve 35. Water sucked to the fuel delivery passage 14 according to lowering down a plunger 4, when fuel in a pressure chamber 12 is pressurized accompanying lift of the plunger 4 to generate a high pressure, is delivered with fuel from a fuel infection passage 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device capable of separating water contained in fuel.

[0002]

2. Description of the Related Art FIG. 10 shows a fuel supply system in which a fuel injection pump for a conventional diesel internal combustion engine (hereinafter, "internal combustion engine") is used in a gasoline engine.
The fuel pumped up from the fuel tank 102 by the low-pressure pump 101 is freed from foreign matters and the like when passing through the fuel filter 103.
05 is sucked into the pressure chamber 106. Fuel injection pump 10
Reference numeral 5 converts the rotational movement of the cam shaft 107 rotating in synchronization with the engine into reciprocating movement of the plunger 108, pressurizes the fuel sucked by the reciprocating movement of the plunger 108, and discharges it from the discharge valve 109 toward the engine.

[0003]

In recent years, in a gasoline engine as well, a fuel injection pump as shown in FIG. 10 is provided in a fuel supply path to the engine for the purpose of improving the engine output and the like, and a high-pressure fuel is supplied to the engine. It is thought to do. However, since gasoline fuel tends to contain more water in the fuel than diesel fuel, if a conventional diesel engine fuel supply device as shown in FIG. However, there is a problem that rust is likely to occur and the malfunction of the plunger, which is a precision sliding component, is caused.

On the other hand, in the fuel supply device for diesel engine as well, as shown in FIG. 11, a water separation container 110 is provided between the fuel tank 102 and the fuel injection pump 105 to remove water contained in the diesel fuel. is there. In the water separation container 110, water precipitates at the bottom of the water separation chamber 110a due to a decrease in the flow velocity of the fuel flowing into the water separation chamber 110a of the water separation container 110 and a difference in specific gravity between the fuel component and water contained in the diesel fuel. . The precipitated water is discharged by manually opening the drain valve 111. If the fuel supply device shown in FIG. 11 is applied to a fuel supply device for a gasoline engine, the amount of water flowing into the fuel injection pump can be reduced, so that the occurrence of rust in the fuel injection pump can be reduced.

However, in the fuel supply device as shown in FIG. 11, it is necessary to manually discharge the water that has settled into the water separation chamber 110a, which causes a problem that maintainability deteriorates. The present invention has been made to solve such a problem, and an object of the present invention is to provide a fuel supply device that automatically removes water contained in fuel and has good maintainability.

[0006]

[Means for Solving the Problems]

(Solution) A fuel supply device according to claim 1 of the present invention for achieving the above object, sucks fuel pumped up from a fuel tank by a low pressure pump into a pressure chamber of a fuel injection pump through a fuel supply passage, A fuel supply device for pressurizing fuel sucked into a pressurizing chamber and discharging the fuel from a fuel discharge passage to an internal combustion engine, the fuel supply device having a flow passage cross-sectional area larger than that of the fuel supply passage, and a fuel component contained in the fuel. A water separation chamber having a volume capable of separating water is provided in the fuel supply passage, and a water discharge passage is provided which is capable of communicating the water discharge port provided at the bottom of the water separation chamber with the fuel discharge passage. Characterize.

The fuel supply system according to claim 2 of the present invention is
The fuel supply device according to claim 1, wherein a water aggregating filter is housed in the water separation chamber. According to a third aspect of the present invention, there is provided the fuel supply apparatus according to the second aspect, wherein the moisture aggregating filter has a foreign matter collecting function. According to a fourth aspect of the present invention, there is provided the fuel supply system according to the first, second or third aspect, further comprising a backflow preventing means for preventing backflow of water from the fuel discharge passage to the water separation chamber. It is characterized in that it is provided in the discharge passage.

The fuel supply system according to claim 5 of the present invention is
5. The fuel supply device according to claim 4, wherein, as the backflow prevention means, a valve seat provided in the water discharge passage, a valve member seated on the valve seat in a water backflow direction, and the valve member on the valve seat. A check valve formed of a spring for urging the water discharge valve or a solenoid valve that opens and closes the water discharge passage by an electromagnetic force is used.

The fuel supply system according to claim 6 of the present invention is
The fuel supply device according to claim 4 or 5, wherein a space portion formed in at least one of the water discharge passage and the discharge passage, which is located between the backflow prevention means and the pressurizing chamber, The space portion has a predetermined volume below a fluid inlet / outlet on the space portion side of the pressurizing chamber.

The fuel supply system according to claim 7 of the present invention is
The fuel supply device according to any one of claims 1 to 6, wherein the fuel discharge passage is disposed toward a discharge valve arranged in the fuel discharge passage on a fuel discharge side with respect to a position where the fuel chamber communicates with the pressurizing chamber. It is characterized by being inclined downward. (Operation and Effect of the Invention) According to the fuel supply device of the first aspect of the present invention, water capable of communicating the bottom of the water separation chamber capable of separating the fuel component and the water contained in the fuel with the fuel discharge passage. By having a discharge passage, water that has settled in the water separation chamber during the fuel intake stroke bypasses the fuel injection pump and is automatically sucked into the fuel discharge side, and from the water separation chamber together with the high-pressure fuel that has been pressurized in the pressure stroke. Inhaled water can be discharged.
Therefore, it is not necessary to artificially discharge the water, so that the maintainability is improved.

According to the fuel supply device of the second aspect of the present invention, the water aggregating filter is housed in the water separation chamber, whereby the water contained in the fuel can be effectively separated from the fuel. According to the fuel supply device of the third aspect of the present invention, since the moisture aggregating filter has a foreign substance collecting function, it is not necessary to provide a fuel filter for removing foreign substances in the fuel in addition to the moisture aggregating filter. Therefore, the number of parts is reduced, so that the number of assembling steps is reduced and the manufacturing cost is reduced.

According to the fuel supply device of the fourth or fifth aspect of the present invention, the backflow preventing means for preventing the backflow of water from the fuel discharge passage to the water separation chamber is provided in the water discharge passage, so that The discharge efficiency to the high pressure injection passage is improved.
According to the fuel supply device of the sixth aspect of the present invention, a space portion is formed in at least one of the water discharge passage and the discharge passage located between the backflow prevention means and the pressurizing chamber, and the space portion is added. By having a certain volume below the fluid inlet / outlet on the space side of the pressure chamber, the water drawn from the water separation chamber collects at the bottom of the space when the engine is stopped, so that water flows into the pressure chamber from the space. Can be prevented.

According to the seventh aspect of the fuel supply apparatus of the present invention, the fuel discharge passage is inclined downward toward the discharge valve disposed in the fuel discharge passage on the fuel discharge side with respect to the position where the fuel chamber communicates with the pressurizing chamber. By doing so, when the engine is stopped, the water sucked from the water separation chamber is collected at the bottom of the space, so that it is possible to prevent water from flowing from the space to the pressure chamber.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a fuel supply system for a gasoline engine according to a first embodiment of the present invention. The fuel injection pump 1 is of a column type, a pump housing 2 is provided with a cylinder 3, and a plunger 4 is reciprocally slidably inserted into the cylinder 3. The lower end of the plunger 4 is engaged with a tappet 7 which is urged downward by a spring 6, and a roller 8 attached to the bottom of the tappet 7 contacts a cam 10 which rotates together with a cam shaft 9. The cam shaft 9 arranged in the cam chamber 11 is connected to a crankshaft of an engine (not shown) and is rotationally driven. The pressurizing chamber 12 is defined by the upper end surface 4 a of the plunger 4 and the inner peripheral wall of the cylinder 3, and communicates with a fuel discharge passage 14 formed in the cylinder 3. The discharge valve 15 is composed of a spring 16 and a ball 17 biased by the spring 16 in the closing direction of the fuel discharge passage 14, and is interposed in the fuel discharge passage 14. The fuel discharge passage 14 communicates with a high pressure injection passage 18 through a discharge valve 15.

An electromagnetic valve 19 for controlling the injection timing is attached to the upper portion of the pump housing 2. A valve member 22 is slidably inserted into a valve body 21 fixed to a valve housing 20 of the solenoid valve 19, and a seat portion 23 is formed at the tip of the valve member 22. The armature 24 fixed to the valve member 22 is biased downward by a spring 25, and is attracted to the iron core 27 by an electromagnetic attraction force when the coil 26 is energized. When the seat portion 23 is seated on the valve seat 21a formed in the valve body 21, the pressurizing chamber 12 and the fuel supply passage 28 communicate with each other, and when the seat portion 23 is separated from the valve seat 21a, the pressurizing chamber 12 is formed. The communication between the fuel supply passage 28 and the fuel supply passage 28 is cut off.

The water separation container 30 is disposed in the middle of the fuel supply passage 28 and is integrally formed with the pump housing 2. A water separation chamber 30a is defined by the water separation container 30 and a part of the pump housing 2. A water aggregating filter 31 is housed in the water separation chamber 30a. The moisture coagulation filter 31 is formed of a glass fiber-containing filter or an ultrafine fiber membrane filter, and causes the moisture contained in the fuel to coagulate / coarse on the filter surface to facilitate precipitation in the bottom portion of the water separation chamber 30a, as well as in the fuel. It also has the function of a fuel filter that removes foreign matter contained in it. The fuel pumped up from the fuel tank 40 by the low-pressure pump 41 flows into the water separation chamber 30a from the bottom of the water separation container 30 through the moisture coagulation filter 31, and is pressurized from the upper part of the water separation container 30 through the fuel supply passage 28. It can be inhaled into the chamber 12.
Since the water separation chamber 30a has a larger flow passage cross-sectional area than the fuel supply passage 28 and has a predetermined volume, when the fuel flows from the fuel supply passage 28 into the water separation chamber 30a, the flow velocity decreases, and in addition to gasoline fuel. Since the specific gravity of water is larger than that of the contained fuel component, the water contained in the gasoline fuel is precipitated at the bottom of the water separation chamber 30a.

A water discharge port 32 is formed at the bottom of the water separation container 30, and the water discharge port 32 communicates with a water discharge passage 33. The check valve 35 is arranged in the water discharge passage 33, and the fuel discharge passage 1 is closed by closing the water discharge passage 33.
It prevents the backflow of fuel and water from 4 to the water discharge passage 33. The check valve 35 has a spring 36 and a ball 37 urged by the spring 36 from the fuel discharge passage 14 toward the water discharge passage 33. The water discharge passage 33 communicates with the fuel discharge passage 14 through the check valve 35.

The solenoid valve 19 controls the fuel injection timing by turning on and off the power supply to the coil 26 according to a command from an electronic control unit (hereinafter referred to as ECU) not shown. That is, the ECU (not shown) grasps the engine operating state from detection signals input from various sensors, calculates the injection timing according to the engine operating state, and turns on the power supply to the coil 26 at the timing at which the injection timing is realized.

Next, the operation of the fuel supply system will be described with reference to FIGS. 1 and 2. FIG. 2 shows a time chart of solenoid valve control for sucking the water in the water separation chamber 30a once during one reciprocation of the plunger 4. (1) For the period shown in FIG. 2, the coil 26 is energized, the solenoid valve 19 is closed, and the plunger 4 is descending from the top dead center. Therefore, the volume of the pressurizing chamber 12 increases as the plunger 4 descends, so the check valve 35 opens, and the water that has settled in the water separation chamber 30a causes the water discharge passage 33, the check valve 35, and the fuel discharge passage. 14 is inhaled. To prevent the water sucked into the fuel discharge passage 14 from being sucked into the pressurizing chamber 12, the coil 26 is de-energized and the solenoid valve 19 is turned off.
Opens.

(2) The plunger 4 continues to descend during the period shown in FIG. Since the solenoid valve 19 is opened, the fuel containing almost no water in the upper part of the water separation chamber 30a is sucked into the pressurizing chamber 12 through the fuel supply passage 28. At this time, the check valve 35 is closed by the biasing force of the spring 16. (3) Even if the plunger 4 starts the lift from the bottom dead center,
Since the solenoid valve 19 is open during the period,
A part of the fuel inside is separated from the fuel supply passage 28 by the water separation chamber 30a.
Is returned to.

(4) When the solenoid valve 19 is closed during the period during the lift of the plunger 4, the fuel in the pressurizing chamber 12 is pressurized with the lift of the plunger 4 to a high pressure, and this fuel pressure is discharged. When the spring set pressure of the valve 15 is exceeded, the discharge valve 15 opens and high-pressure fuel is discharged from the fuel injection passage 18. At this time, the water sucked into the fuel discharge passage 14 during the period is discharged from the fuel injection passage 18 together with the fuel. Check valve 3 depending on fuel supply pressure of low-pressure pump 41
Since the force exerted by the valve 5 in the valve opening direction is smaller than the force exerted by the fuel pressure in the pressurizing chamber 12 on the check valve 35 in the valve closing direction when the plunger 4 is lifted, the check valve 35 opens during the fuel injection. Therefore, the high-pressure fuel does not flow back into the water separation chamber 30a.

Thereafter, by repeating the steps (1) to (4), the water content in the gasoline fuel is reduced by the fuel injection pump 1.
Is bypassed to the fuel injection pump 1 without being sucked into the pressurizing chamber 12, and is automatically sucked to the fuel discharge side, and is discharged together with the fuel in the fuel pressure stroke. In the moisture suction control every time shown in FIG. 2, by setting the energization time of the coil 26 so that the moisture suction amount B per one time is smaller than the fuel discharge amount A per one time, the moisture to the pressurizing chamber 12 is controlled. To prevent the inflow of.

In the solenoid valve control of the comparative example shown in FIG. 3, the solenoid valve is open during the entire period of the downward movement of the plunger, so that the fuel injection device has the same structure as that of the first embodiment shown in FIG. However, water cannot be sucked into the fuel discharge side from the water separation chamber. For this reason, in order to discharge the water that precipitates in the water separation chamber, it is necessary to provide a stopper at the bottom of the water separation chamber and to open this stopper artificially, which deteriorates maintainability.

In the first embodiment of the present invention, moisture does not come into contact with important parts such as the plunger 4 and the solenoid valve 19 so that rusting can be prevented, and the cylinder 3 forming the fuel discharge passage 14 and the check valve. It is possible to prevent a significant increase in cost with a minimum rust-proofing measure such as 35. Further, conventionally, it was necessary to manually discharge the water accumulated in the water separation chamber 30a, but in this embodiment, the water is automatically discharged, and the maintainability can be greatly improved. Moreover, since the foreign matter in the fuel can be captured by the water agglomeration filter 31, the foreign matter collecting fuel filter, the water separation device, and the fuel injection pump which have been independent up to now can be integrated with a simple structure. The cost can be reduced by simplifying and reducing the number of parts. Furthermore, by installing a large volume such as a water separation chamber near the pressurization chamber, pressure pulsation due to backflow of fuel to the fuel supply passage and the water separation device is reduced, so stable fuel intake to the pressurization chamber is possible. become.

(Modification) FIG. 4 shows a time chart of a solenoid valve control of a modification having the same configuration as that of the first embodiment but different in solenoid valve control. In the modification, the solenoid valve 19 is closed only once during the descent of the plunger 4 while the plunger 4 reciprocates n times, and water is sucked from the water separation chamber 30a to the fuel discharge side. Discharge water with fuel during lift. In the other (n-1) times of reciprocating movement of the plunger 4, the solenoid valve 19 is closed only during the plunger lift, and the solenoid valve 19 is opened during the lowering of the plunger 4 for the entire period. Therefore, water is not sucked from the water separation chamber 30a. In the intermittent moisture suction control in which water is sucked only once per n times of fuel discharge, the amount of moisture suction B per time is the total discharge amount of n times (A1 + A2 + ... An).
By setting the energization time of the coil 26 to be smaller, the inflow of water from the fuel discharge passage 14 into the pressurizing chamber 12 is prevented. Further, the amount of sucked water is controlled so that the amount of water that is larger than the volume of the fuel discharge passage 14 is not accumulated.

(Second Embodiment) A second embodiment of the present invention is shown in FIG.
Shown in Components substantially the same as those in the first embodiment are denoted by the same reference numerals. In the second embodiment, the fuel injection pump 1 and the water separation container 50 are constructed separately. Therefore, the fuel injection pump 1 itself can be downsized, and the mountability of the fuel supply device in the engine room is improved.

(Third Embodiment) FIG. 6 shows a third embodiment of the present invention.
Shown in Components substantially the same as those in the first embodiment are denoted by the same reference numerals. In the third embodiment, the water agglomeration filter housed in the water separation container 52 is abolished, and the water content is reduced due to the difference in specific gravity between the fuel component and water and the decrease in the flow velocity of the fuel flowing from the fuel supply passage 28 into the water separation chamber 52a. It separates and precipitates. A fuel filter 53 for removing foreign matters in the fuel is arranged outside the fuel inlet of the water separation container 52.

(Fourth Embodiment) A fourth embodiment of the present invention is shown in FIG.
Shown in Components substantially the same as those in the first embodiment are denoted by the same reference numerals. In the fourth embodiment, an electromagnetic valve 54 is provided in the water discharge passage 33 near the fuel discharge passage to prevent the fuel from flowing backward from the fuel discharge passage 14 to the water discharge passage 33. By controlling the opening / closing of the electromagnetic valve 54 by, for example, an ECU, the amount of water sucked from the water separation chamber 30a to the discharge side of the fuel injection pump 1 via the water discharge passage 33 can be controlled with high accuracy.

(Fifth Embodiment) FIG. 8 shows a fifth embodiment of the present invention.
Shown in Components substantially the same as those in the first embodiment are denoted by the same reference numerals. A space 56 is provided in the fuel discharge passage 14 located between the pressurizing chamber 12 and the check valve 35. The space portion 56 is the fluid inlet / outlet port 12 a on the space portion 56 side of the pressurizing chamber 12.
It has a volume below. By providing the space portion 56 having a volume below the fluid inlet / outlet port 12a,
Moisture sucked into the fuel discharge passage 14 when the engine is stopped collects at the bottom of the space 56, so that even if the vehicle is parked on a slope, for example, the fuel discharge passage 1
It is possible to prevent water from flowing into the pressurizing chamber 12 from 4.

(Sixth Embodiment) A sixth embodiment of the present invention is shown in FIG.
Shown in Components substantially the same as those in the first embodiment are denoted by the same reference numerals. The fuel discharge passage 14 is formed so as to incline downward from the pressurizing chamber 12 toward the discharge valve 15. As a result, when the engine is stopped, etc., the fuel discharge passage 14
Therefore, it is possible to prevent moisture from being sucked into the pressurizing chamber 12.

Although the embodiment of the present invention described above is applied to a fuel injection device for a gasoline engine, the present invention can also be applied to a fuel injection device for a diesel engine.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a fuel supply device according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing opening / closing of a solenoid valve, opening / closing of a check valve, and a change in a plunger stroke volume at every time of sucking water according to the first embodiment.

FIG. 3 is a characteristic diagram showing opening / closing of a solenoid valve, opening / closing of a check valve, and a change in plunger stroke volume according to a comparative example.

FIG. 4 is a characteristic diagram showing opening / closing of a solenoid valve, opening / closing of a check valve, and changes in a plunger stroke volume according to a modification of the first embodiment.

FIG. 5 is a schematic sectional view showing a fuel supply device according to a second embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a fuel supply device according to a third embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a fuel supply device according to a fourth embodiment of the present invention.

FIG. 8 is a schematic sectional view showing a fuel supply device according to a fifth embodiment of the present invention.

FIG. 9 is a schematic sectional view showing a fuel supply device according to a sixth embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view showing a fuel supply device of Conventional Example 1.

FIG. 11 is a schematic cross-sectional view showing a fuel supply device of Conventional Example 2.

[Explanation of symbols]

 1 Fuel Injection Pump 4 Plunger 12 Pressurizing Chamber 14 Fuel Discharge Passage 15 Discharge Valve 19 Electromagnetic Valve 28 Fuel Supply Passage 30 Water Separation Container 30a Water Separation Chamber 31 Moisture Coagulation Filter 32 Water Discharge Port 33 Water Discharge Passage 35 Check Valve 40 Fuel Tank 41 low pressure pump

Claims (7)

[Claims] 1. A fuel pumped from a fuel tank by a low-pressure pump is sucked from a fuel supply passage into a pressure chamber of a fuel injection pump, and the fuel sucked into the pressure chamber is pressurized and discharged from a fuel discharge passage to an internal combustion engine. In the fuel supply device, a water separation chamber having a flow passage cross-sectional area larger than that of the fuel supply passage and having a volume capable of separating water and a fuel component contained in the fuel is provided in the fuel supply passage. A fuel supply device provided with a water discharge passage that is capable of communicating the water discharge port provided at the bottom of the water separation chamber with the fuel discharge passage. 2. The fuel supply device according to claim 1, wherein a water coagulation filter is housed in the water separation chamber. 3. The fuel supply device according to claim 2, wherein the moisture aggregating filter has a foreign substance collecting function. 4. The fuel supply device according to claim 1, wherein the water discharge passage is provided with backflow preventing means for preventing a backflow of water from the fuel discharge passage to the water separation chamber. . 5. A valve seat provided in the water discharge passage, a valve member that is seated on the valve seat in the reverse flow direction of water, and a spring that urges the valve member to the valve seat, as the backflow preventing means. 5. A check valve consisting of or a solenoid valve that opens and closes the water discharge passage by electromagnetic force is used.
The fuel supply device as described in the above. 6. A space portion formed in at least one of the water discharge passage and the discharge passage located between the backflow prevention means and the pressurizing chamber, wherein the space portion is the pressurizing portion. 6. The chamber has a predetermined volume below a fluid inlet / outlet on the space side of the chamber.
The fuel supply device as described in the above. 7. The fuel discharge passage is inclined downward toward a discharge valve arranged in the fuel discharge passage on the fuel discharge side with respect to a position where the fuel discharge passage communicates with the pressurizing chamber. Item 7. The fuel supply device according to any one of items 1 to 6.