DE102007002402A1 - Gas inlet, for a fuel gas to be blown into a motor cylinder, has a hydraulic stroke transformer to convert short actuator stokes into long needle stroke movements to open/close the flow opening - Google Patents

Abstract

The gas inlet for an internal combustion motor, using a gas fuel, has an actuator (4) to move a needle (17) to open and close the opening for gas to blow through. A hydraulic stroke transformer converts a short actuator stroke into a long needle stroke movement. The transformer, filled with a fluid, has an actuator piston (9) through a rear opening to act on the fluid to move the needle piston (10) through a front opening. A seal (11) is between the rear opening and the housing (2) forming a sealing chamber (12) and a similar seal (13) at the front opening forms a sealing chamber (14). A channel (15) connects the two chambers.

Description

The The present invention relates to a gas injection device for a Internal combustion engine according to the preamble of claim 1

From the DE 697 02 893 Such a gas injection device for an internal combustion engine is known, which comprises an injection port, a needle and an actuator for closing the needle between a closed position in which the injection port is closed by the needle and a blow-in position in which the injection port is opened. and move. Gas is injected through the injector directly into a cylinder of the internal combustion engine. By direct injection, a very good, environmentally friendly combustion is possible.

Around a motor vehicle with an internal combustion engine that uses gas, to operate relatively large Gas volume in very short time units using the gas injection device be blown. This must have a Cross sectional area open be at least one order of magnitude (factor 10) about the cross-sectional area of a typical gasoline injector.

adversely is that the Gas injection designed large must become, about the injection of very large Allow gas volume in very short time units, thereby undesirably much Space occupied by the cylinder.

Of the The present invention is based on the object, a fuel injection device for one To create an internal combustion engine that occupies little space and at the same time allows the injection of sufficient amounts of gas in very short time units.

The The object underlying the invention is achieved by a gas injection device for an internal combustion engine having the features of the characterizing part of the claim 1 solved.

According to the invention is a hydraulic lifting transformer provided to a movement of the actuator with a relatively small stroke in one movement of the needle with one relatively large To transform stroke.

advantageously, An actuator can be used that is not suitable for one sufficient lift to ensure adequate gas supply.

In a preferred embodiment comprises the hydraulic lifting transformer is a filled with a fluid completed Volume, which is a rear opening has, in which a reciprocating piston is inserted, and has a front opening, in which a needle actuating piston introduced is.

advantageously, is such a hydraulic lifting transformer durable and stable.

In a development of the preferred embodiment is a rear Seal provided between the reciprocating piston and the housing behind the rear opening, so that one rear seal chamber is formed, and is a front seal between the needle actuating piston and the housing in front of the front opening provided so that a front seal chamber is formed, and connects a pipe the anterior chamber with the posterior chamber.

advantageously, The lifting transformer can be completely sealed.

In a preferred embodiment comprises the hydraulic lifting transformer a damping device to vibrations to dampen the needle.

advantageously, let yourself This will better dose and increase the amount of injected gas.

In a development of the preferred embodiment is the completed Volume through the damping device divided into at least two sub-volumes, is the damping device designed as a throttle, which is a fluid connection between the at least forms two partial volumes, and the damping device is arranged so that this Fluid through the throttle during the movement of the actuator flows through.

advantageously, let yourself Such a damping device for one simply reposition hydraulic lifting transformer through one or more holes.

In Yet another embodiment of the preferred embodiment is one of at least two partial volumes as a rear transformer chamber with relative great Cross-section formed in which the rear opening is provided, and is one of the at least two sub-volumes as a front transformer chamber formed with a relatively small cross-section, in which the front opening provided is.

advantageously, are cylindrical chambers for Hydraulic lifting transformers particularly suitable.

In still another embodiment of the preferred Embodiment, the fluid is based on silicone oil, glycerin, mineral oil or synthetic oil.

advantageously, are silicone oil or glycerin, mineral oil or synthetic oil especially due to its high viscosity suitable for a vibration damping to care.

In Yet another embodiment of the preferred embodiment is the throttle formed as a hole.

advantageously, can through a hole with suitable dimensions vibration especially good repressed without hindering the flow of fluid too much.

In still a preferred embodiment a stroke sensor is provided to detect a stroke of the needle.

advantageously, The stroke sensor can either direct the needle stroke or indirectly measure by the displacement of the sliding element.

In still a preferred embodiment the closed volume with one of the two seal chambers on a check valve connected.

advantageously, can through the check valve prevents a decrease in the amount of fluid in the transformer chambers become.

In a development of the preferred embodiment, the check valve a valve channel.

In Yet another refinement of the preferred embodiment is the valve channel formed in the housing.

In Yet another refinement of the preferred embodiment is the valve channel in the needle actuation piston educated.

In Yet another embodiment of the preferred embodiment comprises the check valve a closing ball and a spring.

In a development of the preferred embodiment is the check valve designed as a diaphragm valve.

In still a preferred embodiment the needle can be controlled by an active vibration damping control.

advantageously, can be an ideal vibration-free operation of the valve at the same time optimal dynamics can be achieved.

in the The following is the invention with reference to the drawings described in more detail. Show it:

1 a cross section of a Gaseinblasvorrichtung in the closed position;

2 a cross section of the gas injector 1 in the blowing position; and

3 a cross section of another gas injection device.

1 shows a cross section of a Gaseinblasvorrichtung in the closed position. Gas is through a supply line 1 at the rear end of the cylindrical housing 2 to an actuator room 2 in which an actor 4 , preferably a piezoelectric actuator, is supplied, and then flows through a channel 5 continue into a blowing room 6 at the front end of the gas injector.

Between the actuator room 3 and the blowing room 6 a lifting transformer is provided. The lifting transformer comprises a rear cylindrical transformer chamber 7 with large cross-section and a front cylindrical transformer chamber 8th with a small cross section, in the case 2 are formed. In a rear opening of the transformer chamber 7 with a large cross-section is a cylindrical piston 9 introduced, so that this opening is closed. In a front opening of the transformer chamber 8th with a small cross-section is a needle actuating piston 10 introduced, so that this opening is closed. The transformer chamber 7 with large cross-section and the transformer chamber 8th with a small cross section are through a throttle 16 separated from each other, which consists of a cylindrical plate in which a small hole is formed and the front inner wall of the transformer chamber 7 attached with large cross-section by screws. Instead of a hole, a plurality of holes, a grid structure or porous material may be provided. The transformer chambers 7 and 8th are filled with a fluid such as glycerol or silicone oil. The reciprocating piston 9 and the needle actuating piston 10 close the corresponding openings into which they are inserted, but not completely tight. Therefore, the fluid between the housing 2 and the reciprocating piston 9 or the needle actuating piston 10 escape. To the further exit of the fluid in the actuator space 2 and blowing room 6 To prevent is between a rear tapered end of the reciprocating piston 9 and the housing 2 an annular corrugated seal 11 made of an elastic material, so that a rear seal chamber 12 is educated, and is between the needle actuating piston 10 and the housing 2 an annular corrugated seal 13 provided of an elastic material, so that a front seal chamber 14 is trained. The seal chambers 12 and 14 are also filled with the fluid, because the fluid can not only from the transformer chamber 7 with large cross-section and the transformer chamber 8th leak with a small cross-section, but also enter the same way, and in particular the entry of air must be prevented. The rear seal chamber 12 and the front seal chamber 14 are through a lead 15 connected with each other. This results in a pressure equalization between the seal chambers 12 and 14 instead of. This is particularly important when the seal chambers are bulging to damage the seals 11 and 13 during the movement of the reciprocating piston 9 and the needle actuating piston 10 to prevent.

The reciprocating piston 9 bumps the actuator with its rear end 4 , so that a movement of the actuator 4 due to its expansion along the gas injection device to the reciprocating piston 9 is transmitted. The needle actuation piston 10 is integral with the needle 17 formed, which closes an injection opening, which in the housing 2 is formed and in the blowing room 6 , The needle actuating piston and the needle can also be separated from each other. In the blowing room 6 is a spring 18 added. This spring 18 pushes against a lead 19 ringing around the needle 17 or the needle actuating piston 10 runs and brings the outward opening needle 17 thereby in its closed position, in which a stop edge at the front end of the needle 17 presses against a needle seat, which is formed in the injection opening, so that the injection opening is closed.

2 shows the gas injector 1 in the blowing position. During the transition from the closed position to the blowing position, the actuator expands 4 in the longitudinal direction, so that the reciprocating piston 9 pushed forward, causing the fluid in the transformer chamber 7 with a large cross section through the hole of the throttle 16 into the transformer chamber 8th pressed with a small cross section. This will cause the needle actuation piston 10 and the needle 17 pushed forward, and becomes the spring 18 pressed together. Due to the different cross sections of the transformer chamber 7 with the large cross-section and the transformer chamber 8th with the small cross section while the needle actuating piston 10 moved much further than the actor 4 expands. The gear ratio is adapted to the desired amount of gas and can, for example 5 be. Between the stop edge at the front end of the needle 17 and the needle seat 29 creates a gap through which the gas can flow.

If the actor 4 contracts again, the fluid flows out of the transformer chamber 8th with a small cross section through the hole in the throttle 16 into the transformer chamber 7 with a large cross section, eliminating the needle 17 through the spring 18 is moved back into the closed position, and the injection opening is closed.

Due to the high number of revolutions of the engine, the operation of opening and closing the injection opening repeatedly takes place in rapid changes. This will be the needle 17 and the entire injection device is excited to vibrate. However, the vibrations are due to the friction that occurs when the fluid passes through the throttle 16 flows so attenuated that the needle movement function can be described approximately as an aperiodic limit case.

3 shows a cross section of another gas injection device. For identical elements, the same reference numerals are used. The further Gaseinblasvorrichtung additionally includes a check valve, which in the reciprocating piston 9 is formed and a closing ball 20 characterized by a spring 21 is biased. When the pressure in the rear sealing chamber 12 larger than in the transformer chamber 7 is, the closing ball 20 lifted off its seat, and the fluid can pass from the rear seal chamber through a valve port 22 into the transformer chamber 7 stream. A similar check valve can also be used in the needle actuation piston 10 be educated. The check valve may also be formed in the housing and on the reciprocating piston 9 or needle actuation piston 10 be passed. By such a check valve may decrease the amount of fluid in the transformer chambers 7 . 8th be prevented, and there is a balance between the amounts of fluid in the seal chambers 12 . 14 and the transformer chambers 7 . 8th one. The further gas injection device also has an optical stroke sensor 23 on, the displacement of a dent 24 detected, the annular outside around the needle actuating piston 10 runs. A throttle 25 is on the inner wall of the chamber 8th attached with a small cross-section.

1

supply

2

casing

3

actuator chamber

4

actuator

5

channel

6

Air supply

7

transformer chamber with big cross-section

8th

transformer chamber with a small cross section

9

reciprocating

10

Needle actuating piston

11

poetry

12

seal chamber

13

poetry

14

seal chamber

15

management

16

throttle

17

needle

18

feather

19

head Start

20

closing ball

21

feather

22

channel

23

stroke sensor

24

indentation

25

throttle

Claims (16)

Gas injection device for an internal combustion engine with an injection opening, a needle ( 17 ) and an actuator ( 4 ) to the needle ( 17 ) between a closed position in which the injection opening through the needle ( 17 ), and a Einblasstellung in which the injection opening is opened, reciprocate, characterized in that a hydraulic lifting transformer is provided to a movement of the actuator ( 4 ) with a relatively small stroke in a movement of the needle ( 17 ) with a relatively large stroke. Gas injection device according to Claim 1, characterized in that the hydraulic lifting transformer comprises a closed volume filled with a fluid, which has a rear opening into which a piston ( 9 ), and has a front opening into which a needle actuation piston ( 10 ) is introduced. Gas injection device according to claim 2, characterized in that a rear seal ( 11 ) between the reciprocating piston ( 9 ) and the housing ( 2 ) is provided behind the rear opening, so that a rear sealing chamber ( 12 ) is formed, and that a front seal ( 13 ) between the needle actuating piston ( 10 ) and the housing ( 2 ) is provided in front of the front opening, so that a front seal chamber ( 14 ) is formed, and that a line ( 15 ) the anterior chamber ( 14 ) with the rear chamber ( 12 ) connects. Gas injection device according to one of the preceding claims, characterized in that the hydraulic lifting transformer comprises a damping device ( 16 ) to prevent vibrations of the needle ( 17 ) to dampen. Gas injection device according to claim 4, characterized in that the closed volume is passed through the damping device ( 16 ) is divided into at least two sub-volumes that the damping device ( 16 ) is formed as a throttle, which forms a fluid connection between the at least two sub-volumes, and that the damping device ( 16 ) is arranged so that the fluid through the throttle during the movement of the actuator ( 4 ) flows through. Gas injection device according to Claim 5, characterized in that one of the at least two partial volumes is in the form of a rear transformer chamber ( 7 ) is formed with a relatively large cross section, in which the rear opening is provided, and that one of the at least two partial volumes as a front transformer chamber ( 8th ) is formed with a relatively small cross-section, in which the front opening is provided. Gas injection device according to claim 5 or claim 6, characterized in that the Fluid on silicone oil, Glycerine, mineral oil or synthetic oil based. Gas injection device according to one of claims 5 to 7, characterized in that the throttle is formed as a hole. Gas injection device according to one of the preceding claims, characterized in that a stroke sensor ( 23 ) is provided to a stroke of the needle ( 17 ) capture. Gas injection device according to one of the preceding claims, characterized in that the closed volume with one of the two sealing chambers ( 12 . 14 ) is connected via a check valve. Gas injection device according to claim 10, characterized in that the check valve has a valve channel ( 22 ) having. Gas injection device according to claim 11, characterized in that the valve channel ( 22 ) in the housing ( 2 ) is trained. Gas injection device according to claim 11, characterized in that the valve channel ( 22 ) in the needle actuating piston ( 9 ) is trained. Gas injection device according to claim 12 or claim 13, characterized in that the check valve is a closing ball ( 20 ) and a spring ( 21 ). Gas injection device according to claim 11, characterized characterized in that Check valve as Diaphragm valve is formed. Gas injection device according to one of the preceding claims, characterized in that the needle ( 17 ) can be controlled by a suitable active control for vibration damping.