KR20070064542A - Injection device for fuel motors - Google Patents

Abstract

An injection device for a fuel motor is provided to enable boot rate shaping and inject a small amount of fuel under a lower pressure in a combustion chamber of the fuel motor. An injection device for a fuel motor includes a fuel reservoir(1), a high pressure fuel conveyance device(2), a pressure tank(3), a 3/2 way valve(4), and an injector(7). The fuel reservoir stores fuel. The high pressure fuel conveyance device conveys fuel with a pressure of 600 to 2500 bar. The pressure tank receives the fuel conveyed by the high pressure fuel conveyance device. The 3/2 way valve is connected to the pressure tank. The 3/2 way valve supplies the fuel to the injector depending on its adjustment position. In a first position(4.1) of the 3/2 way valve, a connection pipe(10.2) having a pressure regulation valve and a adjustable neck is separated from the 3/2 way valve.

Description

Injection device for fuel motors {INJECTION DEVICE FOR FUEL MOTORS}

1 is a schematic view of an injection device for a fuel motor.

2 is a schematic view of another embodiment of an injection device for a fuel motor.

<Drawing symbol>

1: fuel reservoir

2: high pressure fuel carrier

3: fuel tank / rail

4: 3/2 way valve

4.1: 1st position of 3/2 way valve

4.2: 2nd position of 3/2 way valve

5: 2/2 way valve for adjustment of 3/2 way valve

6: 2/2 way valve

7: pressure controlled injection valve / pressure controlled injector

7.1, 9.7: spring

7.2: Nozzle Needle

8.1: Pressure Retention Valve

8.2: Adjustable Neck

9: cap-controlled injection valve / cap-controlled injector

9.1: lower pressure chamber

9.3: Upper pressure chamber

9.4: Nozzle Needle

9.5: Spill Neck

9.6: Supply Neck

10.1: Fuel Conduit to Injector

10.2: narrowed connection conduit

10.3: Fuel Conduits on the Rails

10.4: connecting conduits

The present invention relates to an injection device for a fuel motor.

Injection systems, such as, for example, common rail systems, that inject fuel at variable pressures, have a very rapid injection rate, at least for initiation of injection. Large amounts of fuel are injected at high pressure. However, this negatively affects the nitric oxide release rate (NO _x − release rate). A stepped injection rate is achieved through staged release / opening of the injection nozzle, in particular through a boot rate shaping, whereby the release rate is advantageously maintained.

Injectors for fuel motors for achieving injection rate control in the state of the art are already known. In one possible embodiment of such an injector for a fuel motor, a 2/2 way valve is connected to a common rail injector controlled by a cap. At one valve position of the 2/2 way valve, the maximum pressure generated from the high pressure fuel delivery device of the fuel stored in the pressure tank (rail) is applied to the injector. Injection of the fuel under pressure in the combustion chamber of the fuel motor is realized by release of the injector cap. The pressurized fuel conduit leading to the injector at another valve position is depressurized through the neck and pressure control valve so that a smaller pressure is applied to the injector. Fuel that is pressurized in the combustion chamber is also injected by dismantling the injector cap and, if necessary, under a lower pressure.

Manufacturers of injection systems and diesel motors equipped with such injection systems have sought to find alternatives to inject less fuel at lower pressures in the combustion chamber of the fuel motor and to control injection rates for initiation of injection.

An object of the present invention is to provide a novel fuel motor injector which realizes injection rate control by another method.

This problem is solved through the injection device for a fuel motor according to claim 1.

We control injection rate through a series connection of 3/2 way valves for capped injectors and through a 3/2 way valve and a connected 2/2 way valve for pressure controlled injectors. We found that (boot rate shaping) can be achieved.

The inventors have, from the knowledge obtained, at least provided with a pressure controlled injection valve in which a 2/2 way valve is connected in series to connect or disconnect the pressure tank in which the pressurized fuel is present with the injection valve controlled under pressure. Injector for fuel motors, in which the 3 / 2-way valve is connected to the 2 / 2-way valve in the direction of hydraulic flow and in one regulating position of the 3 / 2-way valve the pressure tank is connected to the 2 / 2-way valve Proposes an injector for a fuel motor with an improvement that the 2/2 way valve is connected to a pressure reduced connection conduit.

Selecting or no pressure is applied to the pressure-controlled injection valve through the opening or closing of the 2 / 2-way valve, which opens or closes the injection valve. To inject less fuel at lower pressure in the combustion chamber of the fuel motor for boot rate shaping and for initiation of injection, the 3/2 way valve and the 2/2 way valve are adjusted as follows. do:

The fuel under high pressure in the first position of the 3/2 way valve is transported from the pressure tank via the fuel conduit via the 3/2 way valve. The 3/2 way valve is then adjusted to the second position. This reduces the pressure in the fuel conduit to a predetermined pressure value through a connecting conduit with an adjustable neck and a pressure retention valve. The 2/2 way valve is opened so that the decompressed fuel can be injected through the open nozzle needle.

To inject more fuel at high pressure into the combustion chamber of the fuel motor, the 3/2 way valve is adjusted to the second position and to the second point when the 2/2 way valve is opened and the 2/2 way valve Fuel is fed directly from the pressure tank to the injector when it is opened. In one possible embodiment of the invention the pressure-controlled injection valve may have a nozzle needle held at least in the closed position through the spring element. Pressure may be supplied to the injection valve to open the injection valve against the spring pressure and allow fuel to enter the combustion chamber. At least a pressure retention valve may be arranged in the connecting conduit. A pressure retention valve is used to accurately maintain the internal pressure of this conduit.

The connecting conduit may be arranged with an adjustable neck in addition to the pressure retention valve. With this adjustable neck an accurate predetermined fuel pressure is set between injection processes.

In addition to the conventionally disclosed injector for fuel motors, the present inventors also provide an injector for a fuel motor, which includes at least an injection valve regulated by a cap and a pressure tank in which fuel is present in a pressurized state, wherein the 3 / 2-way valve is an injection valve Injector for another fuel motor connected in series with an improvement in that the pressure tank is connected to the injection valve in one regulating position of the 3/2 way valve and the injection valve is connected to the pressure-reduced pressure control conduit in another position. Suggest. With this fuel motor injector, it is also possible to inject a smaller amount of fuel under smaller pressure in the combustion chamber of the fuel motor to start the injection.

To implement a cap regulated injection valve, in one embodiment the injection valve may have nozzle needles forming upper and lower pressure chambers through which fuel can be supplied under pressure. For example, one opening is opened to lower the pressure in one chamber and the needle moves through this pressure difference. Such opening of the chamber can be realized through at least one regulating device, in particular a 2/2 way valve, which opens or closes at least the pressure chamber.

In order to realize a limited pressure drop in the chamber, it is advantageous for the pressure inlet cross section in the at least one pressure chamber to be smaller than the pressure outlet cross section. At least one pressure retention valve and / or adjustable neck may be arranged in the connection conduit.

 Preferred embodiments of the invention are presented by the dependent claims and the following description. Two embodiments of the present invention will be described in detail with reference to the two figures, but the present invention is not limited to this embodiment.

Hereinafter, the present invention will be described with reference to FIGS. 1 and 2.

1 shows a schematic view of an injection device for a fuel motor. This embodiment of the invention is suitable for a pressure controlled injection valve / injector 7 and also an injection valve / injector that opens when fuel pressure is applied.

The fuel in the fuel reservoir 1 is conveyed to the pressure tank 3 via a high pressure fuel carrier 2 having a pressure of 600 to 2500 bar. A 3/2 way valve 4 connected to the pressure tank 3 supplies fuel to the injector 7 according to its adjustment position. In the first position (4.1) of the 3 / 2-way valve, the narrowed connection conduit (10.2) with the pressure retention valve (8.1) and the adjustable neck (8.2) is separated from the 3 / 2-way valve (4). At the same time fuel can be supplied from the pressure tank 3 to the injector 7 via the combined fuel conduits 10.3 and 10.1 via the 3/2 way valve 4 when the 2/2 way valve is opened. The fuel pressure applied to the nozzle needle 7.2 moves the nozzle needle against the spring pressure of the spring 7.1, thereby freeing the injection cross section and guiding fuel in the combustion chamber.

The fuel conduit 10.1 is narrowed when the 2/2 way valve 6 is opened (valve 6 in FIG. 1 is closed) in the second position (4.2) of the 3/2 way valve shown in FIG. The conduit 10.2 is connected with a pressure retention valve 8. 1 and an adjustable neck 8. 2 to reduce the pressure in the conduit 10.1. At the same time the fuel conduit 10.3 is disconnected from the fuel tank 3 at the illustrated position 4.2 of the 3/2 way valve. In order to inject less fuel under less pressure in the combustion chamber of the fuel motor to initiate the injection, the 3/2 way valve 4 and the 2/2 way valve 6 are adjusted as follows:

The fuel under high pressure in the first position (4.1) of the 3/2 way valve (4) is carried from the pressure tank (3) via the fuel conduit (10.3) via the 3/2 way valve (4). The 3/2 way valve 4 is then adjusted to the second position. This reduces the pressure in the fuel conduit 10.1 to a predetermined pressure value via a connecting conduit 10.2 with an adjustable neck 8. 1 and a pressure retention valve 8.2. The 2/2 way valve 6 is opened so that the decompressed fuel can be injected through the open nozzle needle 7.2.

In order to inject a greater amount of fuel under high pressure into the combustion chamber of the fuel motor, the 3/2 way valve 4 is adjusted to position 4.1 and the fuel is released from the pressure tank 3 when the 2/2 way valve is opened. It is supplied to the injector 7.

2 shows a schematic view of another embodiment of an injector for a fuel motor. This embodiment is suitable for the injection valve / injector 9 which is controlled by the cap.

Control in boot rate shaping is realized with a 3/2 way valve 4 connected to the pressure tank 3 as in FIG. 1. In the first position (4.1) of the 3 / 2-way valve, the narrowed conduit (10.2) with the pressure retention valve (8.1) and the adjustable neck (8.2) is separated from the 3 / 2-way valve. At the same time fuel can be supplied from the pressure tank 3 to the injector 7 via the fuel conduits 10.3 and 10.1 connected via the 3/2 way valve when the 2/2 way valve 6 is opened.

When the 2 / 2-way valve 9.1 is opened in the second position 4.2 of the 3 / 2-way valve shown in FIG. 2, the fuel conduit 10.1 passes through the narrowed connection conduit 10.2 and the pressure retention valve 8. 1. And a pressure in the conduit 10.1 in connection with the adjustable neck 8.2. At the same time the fuel conduit 10.3 is disconnected from the fuel tank 3 at the illustrated position 4.2 of the 3/2 way valve.

Unlike the pressure controlled injection valve in FIG. 1, the opening and closing of the nozzle needle 9.4 is controlled via a 2/2 way valve 9.1 in the fuel outlet conduit of the injector 9. In the state shown in FIG. 2 the 2/2 way valve 9.1 is closed. The pressure of the fuel is the same in the upper pressure chamber 9.3 and in the lower pressure chamber 9.2. The upper pressure of the upper pressure chamber 9.3 and the lower pressure of the lower pressure chamber 9.2 are balanced relative to the nozzle needle 9.4 so that the nozzle needle 9.4 is kept in the lower position and the spray nozzle cross section is closed. maintain.

In order to start the fuel injection process, the 2/2 way valve 9.1 is opened to open the injection nozzle cross section through the raising of the nozzle needle 9.4. As a result, the upper pressure chamber 9.3 is depressurized.

However, since the cross section of the outlet neck 9.5 is larger than the cross section of the supply neck 9.6, this pressure reduction is limited in the upper pressure chamber 9.3. Fuel that is pressurized in the lower pressure chamber 9.2 can raise the nozzle needle 9.4 to free the injection nozzle cross section. The spring element 9.7 acts against the movement of the nozzle needle and the nozzle needle 9.4 returns to the outflow position upon pressure balancing of the upper and lower pressure chambers 9.2 and 9.3 or after injection.

The above disclosed features and features of the claims can be used not only in each of the above-described combinations but also in other combinations or alone, without departing from the scope of the invention.

According to the injection device for a fuel motor of the present invention, injection rate control (boot rate shaping is possible and the injection can be started with the injection of a smaller amount of fuel at a lower pressure in the combustion chamber of the fuel motor.

Claims (10)

At least a pressure-controlled injection valve 7 in series with a 2 / 2-way valve 6 which connects or disconnects a pressure tank 3 in which the fuel is in a pressurized state with a pressure-controlled injection valve 7. An injector for a fuel motor comprising: A 3/2 way valve (6) is connected to the 2/2 way valve (6) in the direction of hydraulic flow and in one regulating position (4.1) of the 3/2 way valve the pressure tank (3) is connected to the 2/2 way valve ( 6) and a 2/2 way valve (6) in another position (4.2) to a pressure reduced connection conduit (10.2). 2. Injection device for a fuel motor according to claim 1, characterized in that the pressure controlled injection valve (7) has a nozzle needle (7.2) which is held in at least a closed position via a spring element (7.1). 3. Injection device for a fuel motor according to claim 1 or 2, characterized in that at least a pressure retention valve (8.1) is arranged in the connecting conduit (10.2). 4. Injection device for fuel motor according to any one of the preceding claims, characterized in that an adjustable neck (8.2) is arranged in the connecting conduit (10.2). An injector for a fuel motor having at least a pressure tank 3 in which a high pressure fuel is present and an injection valve 9 controlled by a cap, A 3/2 way valve 4 is connected in series to the injection valve 9 and in one regulating position (4.1) of the 3/2 way valve the pressure tank 3 is connected to the injection valve 9 and another position Injector for fuel motor, characterized in that in (4.2) the injection valve (9) is connected to a pressure-reduced connection conduit (10.2). 6. The cap valve controlled injection valve 9 has a nozzle needle 9.4 and the upper and lower portions of the nozzle needle 9.4 to which fuel can be supplied under pressure are pressure chambers 9.3 and 9.2. Injection device for a fuel motor, characterized in that formed. 7. Injection device for a fuel motor according to claim 5 or 6, characterized in that at least a regulating device for opening or closing the pressure chamber (9.3) is arranged, preferably a 2/2 way valve (9.1). 8. Injector according to any one of claims 5 to 7, characterized in that the pressure inlet cross section (9.6) at least in the pressure chamber (9.3) is smaller than the pressure outlet cross section (9.5). 9. Injector according to any one of claims 5 to 8, characterized in that a pressure retention valve (8.1) is arranged in the connection conduit (10.2). 10. Injection device for a fuel motor according to any one of claims 5 to 9, characterized in that an adjustable neck (8.2) is arranged in the connecting conduit (10.2).

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