JPH08218967A - Fuel injection device - Google Patents

Abstract

PURPOSE: To provide a fuel injection device in which either of a delta type injection ratio and a rectangular type injection ratio can be selected. CONSTITUTION: The first solenoid valve 7 arranged on the downstream side of a common rail 5 feeding high pressure fuel is provided with an input port, 7a, an input/output port 7b, and an output port 7c, and the common rail 5 is connected to the input port 7a. When the first solenoid valve 7 is not excited, a passage 8b is connected to the input/output port 7b which is connected to the input port 7a and is cut off from the output port 7c, while in excitation of the first solenoid valve 7, a passage 8c opened to the atmosphere is connected to the output port 7c which is connected to the input/output port 7b and is cut off from the input port 7a. An input port, 9a in the second solenoid valve 9 is connected to the passage 8b so as to be communicated with the input/output port 7b in the first solenoid valve 7. As well as in the first solenoid valve 7, passages 8f, 8e are connected to an input/output port 9b and an output port 9c individually. The passage 8b is connected to a passage 8d communicated with a fuel reserving chamber 14b in a fuel injection valve 10, while the passage 8e is connected to a control chamber 11b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure accumulation type fuel injection device.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Laid-Open No. 165858/1984, there is known a pressure accumulating type fuel injection device having a one-way orifice in a back pressure chamber of a fuel injection valve. Such a fuel injection device is composed of a fuel injection valve 200, a three-way solenoid valve 202, a common rail 204, and a hydraulic pump 206, as shown in FIG. 8, for example. The one-way orifice 213 includes a movable member 211 having an orifice 211a and a compression coil spring 212.

The fuel accumulated in the common rail 204 can be supplied from the first fuel passage 221 to the fuel storage chamber 218 and from the second fuel passage 222 to the back pressure chamber 210 via the three-way solenoid valve 202. Is. Three-way solenoid valve 2
Reference numeral 02 connects the back pressure chamber 210 to the second fuel passage 222 on the low pressure side when the power is turned on, and connects the second fuel passage 222 on the high pressure side to the back pressure chamber 210 when the power is turned off. The energization to the three-way solenoid valve 202 is turned off to supply high pressure fuel to the back pressure chamber side 210, and the energization to the three-way solenoid valve 202 is turned on from the state where the hydraulic piston 216 is seated on the valve seat 219. When 210 is communicated with the fuel passage 222 on the low pressure side, the high pressure fuel in the back pressure chamber 210 is gradually discharged from the orifice 211a to the second fuel passage 222 on the low pressure side. Then, since the hydraulic piston 216 is gently lifted by the fuel pressure in the fuel storage chamber 218, an injection rate (hereinafter, referred to as “delta type injection rate”) in which the injection amount gradually increases immediately after the start of fuel injection is made possible. ing. Here, the injection rate refers to a temporal change rate of the injection amount injected from the fuel injection nozzle.

[0004]

However, according to the pressure-accumulation type fuel injection device as shown in FIG. 8, the one-way orifice in the back pressure chamber always acts regardless of the operating state of the internal combustion engine, so that fuel injection is started. Immediately after that, the fuel injection with the delta type injection rate is required even during high-speed and high-load operation, which requires an injection rate that rapidly increases the injection amount and injects a large amount of fuel in a short period of time (hereinafter referred to as "rectangular injection rate"). Will be done. Then, since the delta injection rate has a longer injection period and the injection end timing is longer than the rectangular injection rate, there is a problem in that NOx increases and smoke becomes worse.

An object of the present invention is to provide a fuel injection device capable of selecting a delta type injection rate or a rectangular type injection rate.

[0006]

According to a first aspect of the present invention for solving the above-mentioned problems, a fuel injection device according to the present invention has a pressure accumulating means having a pressure accumulating chamber for accumulating fuel pressure to a high pressure, and the pressure accumulating means. The fuel reservoir chamber into which the stored high-pressure fuel can flow, a guide hole communicating with the fuel reservoir chamber and formed in the axial direction, an injection hole located at the fuel downstream end of the guide hole, and A valve body having a valve seat located on the fuel upstream side and located on the fuel downstream side of the fuel storage chamber, and reciprocally slidably housed in the guide hole, closed when the valve seat abuts and closed. A valve member that opens, a biasing means that biases the valve member in a direction in which the valve member contacts the valve seat, and a pressure control chamber that controls the valve member to a closed side or an open side, Intermittent switching between the fuel storage chamber and the pressure accumulation chamber, and the pressure control chamber and the pressure accumulation And switches the delta injection rate and the rectangular-type injection rate by intermittent switching of the.

A fuel injection device according to a second aspect of the present invention is the fuel injection device according to the first aspect, wherein first control means for controlling the pressure in the fuel reservoir chamber and pressure in the pressure control chamber are provided. And a second control means for controlling the above, and a delta type injection rate and a rectangular type injection rate are switched by switching control of the first control means and the second control means.

According to a third aspect of the present invention, there is provided a fuel injection system according to the second aspect, wherein the first control means connects the pressure accumulating means and the fuel storage chamber with each other. A first three-way solenoid valve provided in the passage of the first passage, which is connected to the first input port connected to the pressure accumulating means side of the first passage and to the fuel storage chamber side of the first passage. A first input / output port connected to the low voltage side, and the first input / output port when the first input port and the first input / output port are communicated with each other. Disconnecting communication between the port and the first output port,
A first three-way solenoid valve that connects the first input / output port and the first output port when disconnecting the communication between the first input port and the first input / output port; The second control means is provided in a second passage that communicates with the first passage between the first three-way solenoid valve and the fuel storage chamber and that connects the first passage and the pressure control chamber. A second input port connected to the first three-way solenoid valve side of the second passage, and a second three-way solenoid valve connected to the pressure control chamber side of the second passage. A second input / output port connected to the low voltage side, and the second input / output port when the second input port and the second input / output port are communicated with each other. Communication between the port and the second output port is cut off, and the second input port and the second input / output are cut off. Characterized in that it is a second three-way electromagnetic valve which communicates with said second input port and the second output port when to block the communication between the over bets.

Furthermore, a method for controlling a fuel injection device according to a fourth aspect of the present invention is the method for controlling a fuel injection device according to the third aspect, wherein the first input / output port and the first output are provided. The valve member closes the communication between the injection hole and the fuel reservoir by the first control of the first three-way solenoid valve that communicates with the port, the second input / output port and the second output port. The second control of the second three-way solenoid valve that connects the first control port and the first passage to each other is cut off by the second control of the second three-way solenoid valve.
Delta type injection rate control for injecting fuel from the injection hole opened by the third control of the first three-way solenoid valve communicating with the input / output port of the first input port and the first input port A fourth control of the first three-way solenoid valve that communicates with the input / output port, and a fifth control of the second three-way solenoid valve that communicates the second input port with the second input / output port. The control closes the communication between the injection hole and the fuel storage chamber by the valve member, and connects the second input / output port and the second output port to each other by the sixth solenoid valve of the second three-way solenoid valve. And rectangular injection rate control for injecting fuel from the injection hole opened by control.

A fuel injection device according to a fifth aspect of the present invention is the fuel injection device according to the second aspect, wherein the first control means connects the pressure accumulating means and the fuel reservoir chamber with each other. A two-way solenoid valve provided in the passage, the first input port connected to the pressure accumulating means side of the first passage, and the first input port connected to the fuel storage chamber side of the first passage. A two-way solenoid valve for communicating the first input port and the first output port with each other, wherein the second control means includes the two-way solenoid valve and the fuel reservoir. A three-way solenoid valve provided in a second passage communicating with the first passage between the first passage and the pressure control chamber, the two-way electromagnetic valve being the two-way passage of the second passage. A second input port connected to the solenoid valve side is connected to the pressure control chamber side of the second passage. And a second input-output ports, and a second output port connected to the low pressure side, the second
A first control state in which communication between the second input / output port and the second output port is blocked when the input port of the second input port and the second input port are connected to each other; A second control state in which the second input / output port and the second output port are in communication when the communication with the second input / output port is cut off; and the first control state and the second control state It is a three-way solenoid valve in which the second input port and the second output port communicate with each other during transition between the second control state and the second control state.

Further, a method for controlling a fuel injection device according to a sixth aspect of the present invention is the method for controlling a fuel injection device according to the fifth aspect, wherein the second input port and the second input / output port are provided. And a second control of the three-way solenoid valve that causes the second input / output port and the second output port to communicate with each other before the fuel is injected from the injection hole. Control and the third control which repeats the first control and the second control, the communication between the injection hole and the fuel reservoir is closed by the valve member, and the first control is performed.
Type injection rate control for injecting fuel from the injection hole opened by the fourth control for communicating the input port with the first output port, and the first input port and the first output port And the fifth control of the two-way solenoid valve that makes the two-way solenoid valve communicate with each other and the sixth control of the three-way solenoid valve that makes the second input port and the second input / output port communicate with each other. Fuel is injected from the injection hole opened by the seventh control of the three-way solenoid valve that closes the communication with the fuel storage chamber by the valve member and communicates with the second input / output port and the second output port. And a rectangular injection rate control for controlling the injection rate.

[0012]

According to the fuel injection device of the first or second aspect of the present invention, the pressure of the valve body and the first control means for switching between communication and cutoff of the fuel storage chamber of the valve body and the pressure accumulating means. The delta type injection rate and the rectangular type injection rate can be selected by the second control means for switching between communication and cutoff between the control chamber and the pressure accumulating means. Thus, for example, the delta type injection rate is selected during low-speed low-load operation in which the fuel injection timing is fast and the fuel injection characteristic is long, and the high-speed fuel injection characteristic in which the fuel injection timing is slow and the fuel injection period is short is selected. By selecting the rectangular injection rate during high load operation, N
It is effective in reducing Ox and improving smoke.

According to the fuel injection device of the third aspect of the present invention, the fuel storage chamber communicates with the low pressure side via the first three-way solenoid valve by the control of the first three-way solenoid valve and the second three-way solenoid valve. Since the pressure control chamber communicates with the low pressure side via the second three-way solenoid valve by the control of the solenoid valve, when both the fuel storage chamber and the pressure control chamber are communicated with the low pressure side, the fuel storage chamber and the pressure The internal pressure of both the control room and the control room decreases. Further, the valve member moves in the valve closing direction by the urging force of the urging means, and the communication between the injection hole and the fuel reservoir chamber is blocked. When the first three-way solenoid valve is controlled so that the high pressure fuel is supplied from the pressure accumulating means to the fuel storage chamber in this state, the high pressure fuel is gradually supplied to the fuel storage chamber in the low pressure state. As the pressure rises from low pressure to high pressure, the valve member gently moves in the direction of opening the injection hole against the biasing force of the biasing means. Then, since the injection is gently started, the delta type injection rate can be realized. Further, when the fuel reservoir chamber and the pressure accumulating means are communicated with each other by the control of the first three-way solenoid valve, and the pressure control chamber and the pressure accumulating means are communicated with each other by the control of the second three-way solenoid valve, the fuel reservoir chamber and the pressure control are controlled. High pressure fuel is supplied to the chamber. Then, the valve member moves in the valve closing direction to block the communication between the injection hole and the fuel storage chamber. In this state, when the pressure control chamber is made to communicate with the low pressure side by the control of the second three-way solenoid valve, the high pressure fuel is discharged to the low pressure side and the internal pressure of the pressure control chamber sharply decreases. Against this, the valve member moves abruptly in the direction of opening the injection hole. Then, since the injection is suddenly started, the rectangular injection rate can be realized.

According to the control method of the fuel injection device of the fourth aspect of the present invention, both the fuel reservoir chamber and the pressure control chamber are connected to the low pressure side by the first control of the first three-way solenoid valve, and the injection is performed. After the hole is closed by the valve member and the high pressure fuel is prevented from being supplied to the pressure control chamber by the second control of the second three-way solenoid valve, the third control of the first three-way solenoid valve is performed. By the control of 3, the high pressure fuel is gradually supplied from the pressure accumulating means to the low pressure fuel storage chamber. As a result, as the fuel pressure in the fuel storage chamber rises from a low pressure to a high pressure, the valve member gently moves in the direction of opening the injection hole, so that a delta injection rate can be realized. Further, the fuel control chamber is communicated with the pressure accumulating means by the fourth control of the first three-way solenoid valve, and the pressure control chamber is communicated with the low pressure side by the fifth control of the second three-way solenoid valve. As a result, the valve member moves abruptly in the direction of opening the injection hole as the internal pressure of the pressure control chamber drops sharply, so that a rectangular injection rate can be realized.

According to the fuel injection device of the fifth aspect of the present invention, the three-way solenoid valve provided in the second passage is transiting between the first control state and the second control state of the three-way solenoid valve. Since the first input port and the first output port communicate with each other, the fuel storage chamber and the low pressure side are intermittently communicated by repeatedly performing the first control state and the second control state. The internal pressure of the fuel storage chamber can be made lower than the valve opening pressure. When the two-way solenoid valve is controlled so that the high-pressure fuel is gradually supplied from the pressure accumulating means to the low-pressure fuel storage chamber from this state, the valve member is opened as the fuel pressure in the fuel storage chamber rises from the low pressure to the high pressure. The delta type injection rate can be realized by gently moving in the opening direction. Further, if the pressure control chamber is communicated to the low pressure side by the control of the three-way solenoid valve while the fuel storage chamber is communicated with the pressure accumulating means by the control of the two-way solenoid valve, the internal pressure of the pressure control chamber will suddenly decrease. The valve member moves sharply in the direction of opening the injection hole, and a rectangular injection rate can be realized. Therefore, the delta type injection rate and the rectangular type injection rate can be selected by controlling the two-way solenoid valve and the three-way solenoid valve, and there is an effect that the number of relatively expensive three-way solenoid valves used is reduced and the manufacturing cost is reduced.

According to the control method of the fuel injection device of the sixth aspect of the present invention, the first input port and the first input port and the third control are repeatedly performed by repeating the first control and the second control of the three-way solenoid valve. The output port of No. 1 is intermittently communicated with the fuel storage chamber, and the fuel storage chamber is in a low pressure state. From this state, the high pressure fuel is gradually supplied from the pressure accumulating means to the low pressure state fuel storage chamber by the fourth control of the two-way solenoid valve. As a result, as the fuel pressure in the fuel storage chamber rises from a low pressure to a high pressure, the valve member gently moves in the direction of opening the injection hole, so that a delta injection rate can be realized. Further, the fuel control chamber is communicated with the pressure accumulator by the fifth control of the two-way solenoid valve, and the pressure control chamber is communicated with the low pressure side by the sixth control of the three-way solenoid valve. As a result, the valve member moves abruptly in the direction of opening the injection hole as the internal pressure of the pressure control chamber drops sharply, so that a rectangular injection rate can be realized. Therefore, the delta injection rate and the rectangular injection rate can be selected by controlling the two-way solenoid valve and the three-way solenoid valve, and there is an effect of reducing the manufacturing cost.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 3 show a fuel injection device according to a first embodiment of the present invention. As shown in FIG. 1, the fuel tank 1
The fuel sucked up by the fuel pump 3 is pressurized by the fuel pump 3 and supplied to the common rail 5. A first solenoid valve 7 which is a three-way valve is arranged on the downstream side of the common rail 5, and the common rail 5 is connected to an input port 7a of the first solenoid valve 7 via a passage 8a. Therefore, the high pressure fuel in the common rail 5 is supplied to the first solenoid valve 7. When the first solenoid valve 7 is not energized, it communicates with the input port 7a and the output port 7c
The passage 8b is connected to the input / output port 7b of the first solenoid valve 7 which is shut off from the input / output port 7b when energized.
A passage 8c is connected to an output port 7c of the first solenoid valve 7 which communicates with the input port 7a and is cut off from the input port 7a. The end of this passage 8c is connected to the fuel tank 1 and is open to the atmosphere. Further, a fuel storage chamber 1 of a fuel injection valve 10 described later.
A passage 8d communicating with 4b is connected to the passage 8b.

The second solenoid valve 9, like the first solenoid valve 7, has the function of a three-way valve. A passage 8b is connected to the input port 9a of the second solenoid valve 9 and communicates with the input / output port 7b of the first solenoid valve 7. When the second solenoid valve 9 is not energized,
A passage 8f is connected to the input / output port 9b of the second solenoid valve 9 which communicates with the input port 9a and is cut off from the output port 9c, and when energized, communicates with the input / output port 9b and cuts off from the input port 9a. Output port 9 of the second solenoid valve 9
A passage 8e is connected to c. The end of this passage 8e is connected to the fuel tank 1 and is open to the atmosphere. Further, the passage 8f is connected to the control chamber 11b of the fuel injection valve 10.

By adopting the above-mentioned structure, the fuel storage chamber 1 of the fuel injection valve 10 is in the non-energized state of the first solenoid valve 7.
The high-pressure fuel in the common rail 5 is supplied to 4b, and the high-pressure fuel in the common rail 5 is supplied to the control chamber 11b of the fuel injection valve 10 when both the first solenoid valve 7 and the second solenoid valve 9 are in the non-energized state. It is like this. The "first passage" in the claims corresponds to the passage 8a, the passage 8b, and the passage 8d, and the "second passage" in the claims corresponds to the passage 8f. The passage 8c and the passage 8e correspond to the "low pressure side" described in the claims.

Next, the structure of the fuel injection valve 10 will be described. As shown in FIG. 1, the casing 1 of the fuel injection valve 10
1 has a large-diameter piston 12 which is reciprocally movable in the sliding hole 11a.
Is housed. A control chamber 11b defined by one end surface of the large-diameter piston 12 and the inner wall of the casing 11
A passage 8f communicating with the input / output port 9b of the second solenoid valve 9 is connected to the.

On the other hand, in the spring chamber 11c formed on the other end side of the casing 11, a compression coil spring 13 having a shaft portion 12a formed on the other end surface side of the large-diameter piston 12 is housed. There is. The compression coil spring 13 has a collar portion 12b formed at the end of the shaft portion 12a.
Is located between the sliding hole 11a and the spring chamber 11c and an annular convex portion 11d formed on the inner wall of the casing 11, and urges the large-diameter piston 12 toward the nozzle portion 20 described later. are doing.

A nozzle portion 20 is provided on the other end side of the casing 11. A small-diameter piston 15 having a shape capable of reciprocating in the sliding hole 14a is accommodated in the sliding hole 14a formed in the valve body 14. The outer diameter of the small diameter piston 15 is set smaller than the outer diameter of the large diameter piston 12 housed in the casing 11.
One end of the small-diameter piston 15 is connected to the above-mentioned collar 12b of the shaft 12a. A nozzle needle 16 is formed on the other end side of the small diameter piston 15. The outer diameter of the nozzle needle 16 is set smaller than the outer diameter of the small diameter piston 15. An injection hole 19 that can be opened and closed by the nozzle needle 16 is formed at the end of the valve body 14. An annular fuel storage chamber 14 b is formed by the inner wall of the valve body 14 around the connection between the nozzle needle 16 and the small diameter piston 15. Further, a fuel passage 17 communicating with the fuel storage chamber 14b is formed in both the valve body 14 and the casing 11.
The fuel passage 17 is connected to the passage 8d that communicates with the input / output port 7b of the first electromagnetic valve 7 described above.

With the structure described above, the large-diameter piston 12, the shaft portion 12a, the flange portion 12b, the small-diameter piston 15 and the nozzle needle 16 which are integrally connected are reciprocally moved up and down in FIG. The communication with the fuel storage chamber 14b is opened and closed. That is, the sum of the urging force that urges the large-diameter piston 12 downward (valve closing direction) in FIG. 1 by the internal pressure of the control chamber 11b and the urging force of the compression coil spring 13 (hereinafter referred to as "the urging force in the valve closing direction"). ") Is the fuel storage chamber 14
An urging force that urges the small-diameter piston 15 in the upward direction (valve opening direction) in FIG. 1 by the internal pressure of b (hereinafter referred to as “valve opening direction urging force”).
1), the nozzle needle 16 moves downward (valve closing direction) in FIG.
When the communication with b is closed and the biasing force in the valve closing direction is smaller than the biasing force in the valve opening direction, the nozzle needle 16 moves upward (valve opening direction) in FIG. 14b
Open communication with. The "valve member" described in the claims corresponds to the large-diameter piston 12, the shaft portion 12a, the small-diameter piston 15, and the nozzle needle 16.

Next, the operation of the fuel injection system according to the first embodiment will be described. The injection rate of the fuel injection device according to the first embodiment includes a delta type injection rate and a rectangular type injection rate. (1) First, the operation of the fuel injection device that realizes the delta type injection rate will be described with reference to FIGS. 1 and 2. By setting the first solenoid valve 7 shown in FIG. 1 in the energized state and the second solenoid valve 9 in the non-energized state, the input / output port 7b and the output port 7c of the first solenoid valve 7 communicate with each other, and the second solenoid valve 9 input ports 9a
And the input / output port 9b communicate with each other (at the time shown in FIG. 2). Then, the low pressure side communicates with the fuel storage chamber 14b via the first solenoid valve 7, and the second solenoid valve 9 and the first solenoid valve 7 are connected.
Since the low pressure side communicates with the control chamber 11b via the fuel cell, the fuel in the fuel storage chamber 14b and the fuel in the control chamber 11b are discharged from the output port 7c of the first solenoid valve 7. As a result, the fuel storage chamber 14b, the control chamber 11b, the passage 8b,
The internal pressure of the passage 8d and the passage 8f becomes low. At this time, the high-pressure fuel from the common rail 5 is shut off by the first electromagnetic valve 7, and the internal pressure of the fuel reservoir chamber 14b becomes lower than the valve opening pressure of the nozzle needle 16 (hereinafter referred to as "valve opening pressure"). 16 is closed.

Next, the second solenoid valve 9 is energized to cut off the communication between the input port 9a and the input / output port 9b of the second solenoid valve 9 and connect the input / output port 9b and the output port 9c. Make communication (time shown in FIG. 2). The control of the second solenoid valve 9 is performed in order to prevent the high pressure fuel from flowing into the control chamber 11b when the high pressure fuel is supplied to the fuel storage chamber 14b by the control for turning the first solenoid valve 7 into the non-energized state. Then, the communication between the passage 8b and the passage 8f is cut off. At this time, since the low pressure side communicates with the control chamber 11b via the second solenoid valve 9, the control chamber 11b
The internal pressure of is further reduced.

Since the input port 7a of the first solenoid valve 7 and the input / output port 7b communicate with each other by turning off the first solenoid valve 7 from this state, the high pressure fuel from the common rail 5 passes through the passages 8b and 8d. And is supplied to the fuel storage chamber 14b via the fuel passage 17 (the timing shown in FIG. 2).
At this time, since the communication between the input port 9a of the second solenoid valve 9 and the input / output port 9b is cut off, high pressure fuel is not supplied to the control chamber 11b. The fuel injection timing for making the first electromagnetic valve 7 non-energized is the hydraulic response delay time obtained from the respective lengths of the passages 8b and 8d from the input / output port 7b of the first electromagnetic valve 7 and the fuel passage 17. Is set as a prospect.

When high-pressure fuel starts to be supplied to the fuel storage chamber 14b, the internal pressure of the fuel storage chamber 14b gradually rises, and when the valve opening pressure is eventually reached, the nozzle needle 16 is gently lifted and the injection hole 19 and the fuel are discharged. Fuel injection is started by communicating with the reservoir chamber 14b (time shown in FIG. 2). At this time,
Since the high pressure fuel is gradually supplied to the fuel storage chamber 14b in the low pressure state, the internal pressure of the fuel storage chamber 14b gradually rises from the low pressure to the high pressure. Then, the nozzle needle 16 gently lifts as the internal pressure of the fuel storage chamber 14b rises. That is, the injection rate increases with a gentle slope (section shown in FIG. 2).

When the predetermined injection end timing is reached, the second solenoid valve 9 is de-energized (the timing shown in FIG. 2). Then, the input port 9a and the input / output port 9b of the second solenoid valve 9
As a result of the communication between and, the high pressure fuel is supplied from the common rail 5 to the control chamber 11b via the passages 8b and 8f. The supply of high-pressure fuel to the control chamber 11b raises the internal pressure of the control chamber 11b, so that the urging force in the valve closing direction becomes larger than the urging force in the valve opening direction.
Moves instantly in the valve closing direction. Therefore, the communication between the injection hole 19 and the fuel storage chamber 14b is closed, the fuel injection is sharply cut, and the fuel injection is ended (the timing shown in FIG. 2).

As described above, according to the fuel injection system of the first embodiment, the injection rate increases with a gentle inclination as in the section shown in FIG. 2, that is, from the start of injection to the end of injection.
A delta injection rate can be realized in the cycle. (2) Next, the operation of the fuel injection device that realizes the rectangular injection rate will be described with reference to FIGS. 1 and 3. First shown in FIG.
When the solenoid valve 7 is energized and the second solenoid valve 9 is de-energized (timing shown in FIG. 3), high pressure fuel is supplied to the control chamber 11b and the fuel reservoir chamber 14b, and the nozzle needle 16 moves in the valve closing direction. Then, the communication between the injection hole 19 and the fuel storage chamber 14b is cut off. In this state, the second solenoid valve 9 shown in FIG. 1 is energized (timing shown in FIG. 3). At this time, since the first solenoid valve 7 is always energized, the high pressure fuel is constantly supplied from the common rail 5 to the fuel reservoir chamber 14b via the passages 8b and 8d and the fuel passage 17. on the other hand,
Since the second solenoid valve 9 is energized, the control room 11
The internal pressure of b sharply drops. Therefore, the urging force in the valve opening direction becomes larger than the urging force in the valve closing direction, and the nozzle needle 16 lifts to start fuel injection (the timing shown in FIG. 3). Since the high-pressure fuel is constantly supplied to the fuel storage chamber 14b, the nozzle needle 16 that has started to lift abruptly completes the lift (time shown in FIG. 3). Therefore, the injection rate increases with a steep slope (section shown in FIG. 3).

When the predetermined injection end timing is reached, the second solenoid valve 9 is de-energized (timing shown in FIG. 3), and high pressure fuel is supplied from the common rail 5 to the control chamber 11b. As a result, the internal pressure of the control chamber 11b rises and the biasing force in the valve closing direction becomes larger than the biasing force in the valve opening direction, so that the nozzle needle 16 instantaneously moves in the valve closing direction. Therefore, the communication between the injection hole 19 and the fuel storage chamber 14b is closed, the fuel injection is sharply cut, and the fuel injection is ended (the timing shown in FIG. 3).

As described above, according to the fuel injection system of the first embodiment, the first solenoid valve 7 is always energized and only the second solenoid valve 9 is controlled, so that the section shown in FIG. It is possible to realize an injection rate that increases with a certain inclination, that is, a rectangular injection rate in one cycle from the start of injection to the end of injection. According to the first embodiment, the first solenoid valve 7
And the second solenoid valve 9, the control chamber 11 of the fuel injection valve 10
After lowering the internal pressure between b and the fuel reservoir chamber 14b below the valve opening pressure, the nozzle needle 16 is urged in the valve closing direction in order to supply high-pressure fuel to the fuel reservoir chamber 14b by the control of the second solenoid valve 9. The nozzle needle 16 is gently lifted as the internal pressure of the fuel storage chamber 14b rises against the biasing force of the compression coil spring 13. This makes it possible to achieve a delta injection rate. Further, since the first electromagnetic valve 7 is always energized and only the second electromagnetic valve 9 is controlled, the high-pressure fuel is always supplied to the fuel reservoir chamber 14b. Complete the lift. This makes it possible to realize a rectangular injection rate. Therefore, there is an effect that the delta type injection rate and the rectangular type injection rate can be selected by controlling the first electromagnetic valve 7 and the second electromagnetic valve 9.

When the fuel injection valve 10, the first solenoid valve 7 and the second solenoid valve 9 are provided for each cylinder so as to correspond to each cylinder of the multi-cylinder type internal combustion engine, the fuel injection valve 10
If the valve opens or closes poorly, the following configuration and operation make it possible to take measures after the malfunction. Fuel injection valve 1
A pressure sensor for detecting the pressure in the control chamber 11b of 0 or the like or a position sensor for detecting the lift amount of the nozzle needle 16 or the like is attached to each fuel injection valve 10. When a malfunction of the fuel injection valve 10 is detected by this sensor, the supply of high-pressure fuel to the fuel injection valve 10 is cut off by energizing the first electromagnetic valve 7 of the fuel injection valve 10 having the malfunction. Therefore, it is possible to prevent abnormal injection of the malfunctioning fuel injection valve 10 and the like. Further, since the rotational speed of the internal combustion engine fluctuates when the fuel injection valve 10 malfunctions, a sensor for detecting the rotational speed of the internal combustion engine may be used as the sensor for detecting this abnormality.

(Second Embodiment) FIG. 4 shows a fuel injection device according to a second embodiment of the present invention. The same reference numerals are attached to the substantially same components as those in the first embodiment. Second shown in FIG.
The embodiment is an example in which the fuel injection valve 10 corresponding to each cylinder of a four-cylinder type internal combustion engine is controlled by one first solenoid valve 7. Here, the fuel tank 1, the fuel pump 3, the common rail 5, the first solenoid valve 7, the second solenoid valve 9 and the fuel injection valve 1
0 has the same configuration as that of the first embodiment.

As shown in FIG. 4, the first solenoid valve 7 connected to the common rail 5 has four solenoid valves corresponding to the cylinders # 1 to # 4.
Each of the passages 21a, 21b connected to one fuel injection valve 10;
c, d and 22a, b, c, d are connected. These passages 21a, b, c, d correspond to the passage 8b described in the first embodiment, and the passages 22a, b, c, d correspond to the passage 8d described in the first embodiment. That is, the four fuel injection valves 10 including the second solenoid valve 9 are connected in parallel to the first solenoid valve 7.

In the fuel injection device of the second embodiment, the four fuel injection valves 1
Of 0, it is not necessary to control two or more fuel injection valves 10 at the same time. Therefore, while the fuel injection valve 10 of the cylinder # 1 is being controlled, it is necessary to keep the fuel injection valve 10 of the cylinders # 2 to # 4 in the closed state. For that purpose, as described in the first embodiment. First, the second solenoid valve 9 may be de-energized. That is, the second electromagnetic valve 9 of the fuel injection valve 10 that does not need to inject fuel is de-energized, and the second electromagnetic valve 9 and the first electromagnetic valve 7 of the fuel injection valve 10 that needs to inject fuel do the first embodiment. The fuel injection valve 1 that needs to inject fuel by performing the delta type injection rate control described in the example
A delta injection rate of 0 can be realized. Similarly, also in the case of the rectangular injection rate, the second solenoid valve 9 of the fuel injection valve 10 that needs to inject fuel by deenergizing the second solenoid valve 9 of the fuel injection valve 10 that does not require fuel injection. The rectangular injection rate can be realized by performing the rectangular injection rate control described in the first embodiment for No. 9. In this case, the first solenoid valve 7 is always energized.

According to the second embodiment, when controlling a plurality of fuel injection valves 10 whose injection timings do not overlap, if the second solenoid valve 9 of the fuel injection valve 10 that does not require fuel injection is de-energized. Since the valve closed state can be maintained, it is not necessary to dispose the first electromagnetic valve 7 located on the fuel upstream side of the second electromagnetic valve 9 for each fuel injection valve 10. Thereby, one first electromagnetic valve 7 can be shared by the plurality of fuel injection valves 10, and the number of the first electromagnetic valves 7 used can be reduced, and the product cost can be significantly reduced.

(Third Embodiment) FIGS. 5 to 7 show a fuel injection device according to a third embodiment of the present invention. The same reference numerals are attached to the substantially same components as those in the first embodiment. The third embodiment shown in FIGS. 5 to 7 is an example in which the first solenoid valve located on the downstream side of the common rail 5 is a two-way valve and a delta injection rate and a rectangular injection rate are realized.

As shown in FIG. 5, a two-way solenoid valve 51, which is a two-way valve, is connected to the downstream side of the common rail 5 via a passage. The two-way solenoid valve 51 communicates with the input port 51a and the output port 51b when energized, and when de-energized,
The input port 51a and the output port 51b are cut off from each other. The output port 51b is connected to the fuel injection valve 10 via the passage 53.

As shown in FIG. 6, the fuel injection valve 10 is provided with a three-way solenoid valve 130 at its upper portion.
Reference numeral 0 is composed of valve means and drive means for driving the valve means. In the valve means, an outer valve 132 is reciprocally fitted in a cylinder 131a formed in the valve body 131, and an inner valve 133 is reciprocally movable in an inner hole 132a formed in the outer valve 132 so as to extend in the axial direction. Is fitted to. Cylinder 13
The outer seat 140 formed on 1a is the outer valve 1
32 is a valve seat part which separates and contacts, and the inner seat 141 formed in the outer valve 132 is a valve seat part which the inner valve 133 separates and contacts. In the outer valve 132, four through holes 156 are formed to penetrate in the radial direction at intervals of 90 °, for example.

The drive means is fixed to the case 150 via the solenoid housing 134, as a stator 135 as a fixed iron core, the coil 136 attached to this stator 135, and the outer valve 132, and is attracted to the stator 135 side when energized. And a compression coil spring 138 that urges the outer valve 132 to the side opposite to the suction side. The stator 135 as a fixed iron core for fixing the coil 136 is housed in the solenoid housing 134.
34 is housed in a cylindrical case 150.

Through hole 1 formed in outer valve 132
A groove 152 is formed on the inner wall of the cylinder 131a on the radially outer side facing 56, and two fuel passages 154 communicating with the groove 152 are formed in the valve body 131. The fuel passage 154 is provided in the fuel storage chamber 14b.
Is connected to a fuel passage 17 communicating with the. Further, the outer valve 132 is provided with an inner hole 132a.
An inner hole 158 is formed that extends to the lower end in one direction and penetrates therethrough.

The valve body 131 has a fuel passage 154.
Besides, the outer sheet 1 formed in the cylinder 131a
A drain passage 159 that extends radially outward from about 40 and communicates with the low pressure side is formed, and a passage 160 that extends from near the outer seat 140 toward the lower end side in the axial direction and penetrates is formed. One end of this passage 160 communicates with the above-mentioned inner hole 158, and the other end thereof is connected to the cylinder 13
It communicates with a control chamber 11b formed in 1a.

Now, the operation of the three-way solenoid valve 130 will be described. As shown in FIG. 6, when the three-way electromagnetic valve 130 is energized, the movable iron core 137 contacts the stator 135, and the outer valve 132 attached to the movable iron core 137 separates from the outer seat 140. As a result, the fuel passage 154 and the through hole 156 which are in communication with each other are connected.
Is cut off, and the control room 1
1b can communicate with the drain passage 159.

On the other hand, when the three-way solenoid valve 130 is switched from energized to de-energized, it is in a demagnetized state.
The movable iron core 137, which was in contact with, is urged downward in FIG. 6 by the urging force of the compression coil spring. Then, as the movable iron core 137 moves, the outer valve 132 moves downward in FIG. 6, and the fuel passage 154 and the through hole 156, which have been blocked, start to communicate with each other. At this time, since the outer valve 132 is not yet seated on the outer seat 140, the through hole 156 and the inner hole 158 are provided for a short period from the start of communication between the fuel passage 154 and the through hole 156 until the outer valve 132 is seated on the outer seat 140. The fuel passage 154 and the drain passage 159 can communicate with each other via the. That is, the input port 13 of the three-way solenoid valve 130
0a and the output port 130c can communicate with each other. The input port 130a and the output port 13 that occur during this short period
The communication with 0c similarly occurs when the three-way solenoid valve 130 is switched from non-energized to energized.
By repeating de-energization, the input port 130a and the output port 130c are intermittently connected.

The outer valve 132 is the outer seat 140.
When seated on, the inner hole 158 and the drain passage 159 are disconnected from each other, and the through hole 156, the inner hole 158, and the fuel passage 1
The fuel passage 154 communicates with the control chamber 11b via 60. Next, the operation of the fuel injection device according to the third embodiment will be described with reference to FIGS.

The operation for injecting fuel at the delta type injection rate will be described. By turning on the two-way solenoid valve 51 shown in FIG. 5, the supply of high-pressure fuel from the common rail 5 is cut off. After that, the three-way solenoid valve 130 is repeatedly energized and de-energized in such a fast cycle that fuel injection is not performed from the fuel injection valve 10. Then, as described above, since the input port 130a and the output port 130c of the three-way solenoid valve 130 shown in FIG. 5 are repeatedly communicated with each other for a short period of time during which the outer valve 132 of the three-way solenoid valve 130 moves, the fuel of the fuel injection valve 10 is repeatedly communicated. The reservoir chamber 14b has fuel passages 17, 162, 15
4, through the three-way solenoid valve 130 and the drain passage 159, the low pressure side is intermittently communicated. Therefore,
The internal pressure of the fuel storage chamber 14b gradually decreases in a stepwise downward manner as shown in FIG. That is, it is possible to reduce the internal pressure of the fuel storage chamber 14b without using a three-way valve for the two-way solenoid valve 51.

Further, when the three-way solenoid valve 130 is energized, the control chamber 11b and the drain passage 159 communicate with each other via the fuel passage 160, and when the three-way solenoid valve 130 is not energized, the control chamber 11b and the fuel passage 17 are connected. And 3 communicate with each other via the fuel passage 154, the three-way solenoid valve 13 is operated at a fast cycle.
With the energization and de-energization of 0, the internal pressure of the control chamber 11b gradually decreases while repeatedly decreasing and increasing as shown in FIG.

From this state, similar to the first embodiment, the three-way solenoid valve 130 is energized and the two-way solenoid valve 51 is energized so that the high-pressure fuel passes from the common rail 5 to the passage 53,
It is supplied to the fuel storage chamber 14b via 162 and the fuel passage 17. At this time, since the high pressure fuel is gradually supplied to the fuel storage chamber 14b in the low pressure state, the internal pressure of the fuel storage chamber 14b gradually rises from the low pressure to the high pressure. Then, the nozzle needle 16 gently lifts as the internal pressure of the fuel storage chamber 14b rises. That is, the injection rate increases with a gentle slope, and the delta injection rate is realized.

The operation for injecting the fuel of the rectangular injection rate is the first embodiment in which the two-way solenoid valve 51 shown in FIG. 5 is always energized and the three-way solenoid valve 130 is energized or de-energized. The same operation as the fuel injection with the rectangular injection rate described with reference to FIGS. 1 and 3 is possible. According to the third embodiment, since the input port 130a and the output port 130c are intermittently communicated by repeatedly energizing and de-energizing the three-way solenoid valve 130, the high-pressure fuel in the fuel reservoir chamber 14b is supplied to the three-way solenoid valve. It can escape to the low pressure side via 130. As a result, it is not necessary to provide the two-way solenoid valve 51 with a passage communicating with the low pressure side, and the two-way solenoid valve 51 can be a two-way valve that is cheaper than the three-way solenoid valve. Therefore, there is an effect of reducing the product cost.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a fuel injection device according to a first embodiment of the present invention.

FIG. 2 is a time chart showing valve opening and closing control during delta injection according to the first embodiment.

FIG. 3 is a time chart diagram showing valve opening and closing control during rectangular injection of the first embodiment.

FIG. 4 is an overall configuration diagram of a fuel injection device according to a second embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a fuel injection device according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a three-way solenoid valve used in a fuel injection device according to a third embodiment.

FIG. 7 is a time chart diagram showing valve opening and closing control during delta injection in the third embodiment.

FIG. 8 is an overall configuration diagram of a conventional fuel injection device.

[Explanation of symbols]

1 Fuel Tank 3 Fuel Pump 5 Common Rail (Pressure Accumulation Means) 7 First Solenoid Valve (First Control Means, First
3a solenoid valve) 7a, 51a Input port (first input port) 7b Input / output port (first input / output port) 7c, 51b Output port (first output port) 8a, b, d Passage (first Passage 8c, e passage (low pressure side) 8f passage (second passage) 9 second solenoid valve (second control means, second
3a solenoid valve) 9a, 130a Input port (second input port) 9b, 130b Input / output port (second input / output port) 9c, 130c Output port (second output port) 10 Fuel injection valve 11 Casing ( Valve body) 11a, 14a Sliding hole (guide hole) 11b Control chamber (pressure control chamber) 12 Large diameter piston (valve member) 12a Shaft part (valve member) 13 Compression coil spring (biasing means) 14 Valve body (valve) Body) 14b Fuel storage chamber 15 Small diameter piston (valve member) 16 Nozzle needle (valve member) 19 Injection hole 51 Two-way solenoid valve (first control means) 130 Three-way solenoid valve (second control means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02M 47/00 F02M 47/00 P 55/02 350 55/02 350P

Claims (6)

[Claims] 1. A pressure accumulating means having a pressure accumulating chamber for accumulating fuel pressure to a high pressure, a fuel accumulating chamber into which the high pressure fuel accumulated by the accumulating means can flow, and a fuel accumulating chamber formed in the axial direction. A guide hole, a nozzle hole located at an end of the guide hole on the fuel downstream side, and a valve body having a valve seat located upstream of the fuel from the nozzle hole and downstream of the fuel from the fuel reservoir. A valve member that is reciprocally slidably accommodated in the guide hole, closes when the valve seat abuts, and opens when the valve seat separates, and urges the valve member in a direction in which the valve member abuts the valve seat. And a pressure control chamber for controlling the valve member to a closed side or an open side, and intermittent switching between the fuel reservoir chamber and the pressure accumulating chamber and intermittent switching between the pressure control chamber and the pressure accumulating chamber. A fuel characterized by switching between a delta type injection rate and a rectangular type injection rate by Injection device. 2. A first control means for controlling the pressure in the fuel storage chamber, and a second control means for controlling the pressure in the pressure control chamber, wherein the first control means and the second control means are provided. 2. The fuel injection device according to claim 1, wherein the delta injection rate and the rectangular injection rate are switched by switching control with the control means. 3. The first control means is provided in a first passage connecting the pressure accumulating means and the fuel storage chamber.
A three-way solenoid valve, a first input port connected to the pressure accumulating means side of the first passage, and a first input / output port connected to the fuel storage chamber side of the first passage. And a first output port connected to the low voltage side, the first
Of the first input / output port and the first input / output port are cut off, the communication between the first input / output port and the first output port is blocked, and the first input port and the first input / output are connected. A first three-way solenoid valve that causes the first input / output port and the first output port to communicate with each other when the communication with the port is cut off; and the second control means includes the first three-way solenoid valve. A second three-way solenoid valve provided in a second passage communicating with the first passage between the fuel storage chamber and the fuel storage chamber, the second passage being connected to the first passage and the pressure control chamber. The first of the two passages
Second input port connected to the three-way solenoid valve side, a second input / output port connected to the pressure control chamber side of the second passage, and a second output port connected to the low pressure side And when the second input port and the second input / output port are communicated with each other, the second input / output port and the second input / output port
Disconnecting communication with the second output port and disconnecting communication between the second input port and the second input / output port, connecting the second input / output port with the second output port 2. A three-way solenoid valve according to claim 2.
The fuel injection device described. 4. The method for controlling a fuel injection device according to claim 3, wherein the first control of the first three-way solenoid valve that connects the first input / output port and the first output port is in communication with each other. By the second control of the second three-way solenoid valve that closes the communication between the injection hole and the fuel storage chamber by the valve member and connects the second input / output port and the second output port with each other. Disconnecting communication between the pressure control chamber and the first passage,
A delta injection rate control for injecting fuel from the injection hole opened by the third control of the first three-way solenoid valve that connects the first input port and the first input / output port to each other; The fourth control of the first three-way solenoid valve for communicating the first input port with the first input / output port, and the communication for communicating the second input port with the second input / output port The fifth control of the second three-way solenoid valve closes the communication between the injection hole and the fuel storage chamber by the valve member, and connects the second input / output port and the second output port. And a rectangular injection rate control for injecting fuel from the injection hole opened by the sixth control of the second three-way solenoid valve. 5. The first control means is a two-way solenoid valve provided in a first passage connecting the pressure accumulating means and the fuel storage chamber, and the first passage is on the pressure accumulating means side of the first passage. A first input port connected to the first passage, and a first output port connected to the fuel reservoir chamber side of the first passage, the first input port and the first output port Is a two-way solenoid valve that communicates with the second control means, the second control means communicates with the first passage between the two-way solenoid valve and the fuel storage chamber, and the first passage and the pressure control chamber. A three-way solenoid valve provided in a second passage connecting to and a second input port connected to the two-way solenoid valve side of the second passage, and the pressure control of the second passage. A second input / output port connected to the chamber side and a second output port connected to the low pressure side; A first control state in which the communication between the second input / output port and the second output port is cut off when the input port and the second input / output port are communicated with each other; A second control state that allows the second input / output port and the second output port to communicate with each other when the communication with the second input / output port is cut off; and the first control state and the first control state The fuel injection device according to claim 2, wherein the fuel injection device is a three-way solenoid valve in which the second input port and the second output port communicate with each other during transition between the two control states. 6. The method for controlling a fuel injection device according to claim 5, wherein the first control of the three-way solenoid valve that makes the second input port and the second input / output port communicate with each other, Before the fuel is injected from the injection hole, the second input / output port and the second
Communication between the injection hole and the fuel reservoir by the second control of the three-way solenoid valve for communicating with the output port and the third control for repeatedly performing the first control and the second control. Is controlled by the valve member, and the fuel is injected from the injection hole opened by the fourth control for communicating the first input port and the first output port with each other; Control of the two-way solenoid valve for communicating the input port with the first output port, and the third control of the three-way solenoid valve for communicating the second input port with the second input / output port. By the control of 6, the communication between the injection hole and the fuel storage chamber is closed by the valve member, and by the seventh control of the three-way solenoid valve that communicates with the second input / output port and the second output port. Fuel is injected from the opened nozzle hole. And a rectangular injection rate control for controlling the fuel injection device.