JPS6198959A - Fuel injector for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The invention relates to a fuel injection device for an internal combustion engine, comprising: at least one pump piston forming a first pump working chamber in a first pump cylinder; At least one second pump piston forming a second pump working chamber in the second pump cylinder and a rotationally driven distribution member supported in the distribution nozzle are provided. one pump cylinder is located in a first radial plane and a second pump cylinder is located in a second radial plane, the distribution member defining a first distribution opening and a second distribution opening. , the distribution opening is brought into contact with the injection conduit extending from the distribution cylinder leading to the injection point of the internal combustion engine in sequence during the pump piston transport stroke during rotation of the distribution member, and the distribution opening a first pump working chamber and a second pump working chamber are connected via a conduit, the pump working chambers being connectable via a fuel supply conduit having a metering device; a cam ring located within the radial plane and a second radial plane, and a pump drive, the cam ring having a radially oriented cam in the cam face and the pop drive. The device causes the cam ring and the pump ston to move in the rotational direction relative to each other in synchronization with the rotation of the distribution member in order to reciprocate the bon 7'' suspension ston, and the cam of the cam ring and the pump ston The mutual relationship with the piston and the mutual angular spacing of the distribution openings are selected such that the operation of the first pump piston is offset by this angular spacing relative to the operation of the second pump piston. Regarding formal matters.

Conventional technology The chambers are separated from one another and are each connected in a rigid and alternating manner via a pressure line and a control valve to a fuel metering device during the suction stroke or to a distribution element during the conveying stroke, in this case at the same time. The other Bonf0 working chamber is connected to the relief chamber via a control valve and a pressure line.The known device is extremely expensive, especially due to the control valves used in this device. There is.

Means for Solving the Problems In an embodiment of the invention, the first pump working chamber and the second pump working chamber are connected via a common pressure conduit and a first passage branching off from this pressure conduit. the first distribution opening and at the same time is connected to the second distribution opening via a second passage branching off from the pressure conduit and connectable via a common suction conduit with a fuel supply conduit having a metering valve. It looks like this.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the housing of the radial piston distribution injection pump shown in FIG. At the end 4 of the distribution member projecting from the distribution/cylinder, the distribution member has a large-diameter section, which in a first radial plane 6 lies diametrically opposite radial sections. It has two first pump cylinders 7 extending from one side to the other. In a second radial plane 8 parallel to the first radial plane there are furthermore two second pump cylinders 9 with radially opposite positions located diametrically opposite each other. It is located within the end 4 of the enlarged distribution member.

Furthermore, this end is coupled or power connected to the pump drive shaft 10.

In each first pump cylinder γ a first pump piston 12 and in each second pump cylinder 2 a second pump piston 13 is movably mounted. On its end side, the pump piston forms a first pump working chamber 14 or a second pump working chamber 15 in the pump cylinder, which pump working chambers are connected to one another by a transverse channel 16 or a transverse channel 17 in the distribution member. has been done. The two transverse channels are permanently connected to each other via a pressure line 18 extending axially within the distribution member. The pressure line 18 (in the axial direction, the second transverse passage 17 also leads into the first transverse passage 16 and into the portion of the distribution member, which is designed as a blind hole and which is seated in the distribution/cylinder). A radial channel 19 branches off from the pressure line 18, preferably corresponding to the number of suction strokes of the pump piston per rotational speed of the distribution element and the division of the suction stroke. It communicates with an annular groove 20 arranged on the surface, which is connected to a fuel supply conduit 22 which communicates with the distribution cylinder 2 .

Two radial channels 23, 24, which are offset from each other by an angle α=135°, branch off from the further V pressure conduit 18, and which are connected to a first distribution opening in the circumferential surface of the distribution member. 25 and a second distribution opening 26 . In the radial plane in which the distribution opening is located, an injection conduit 27 branches off from the distribution leader, which injection conduit 21 is arranged on the circumferential surface in accordance with the number of cylinders to be supplied and the cylinder division of the internal combustion engine. distributed and arranged. The injection conduit leads from the pump housing to a schematically illustrated fuel injection valve 28. In the illustrated example, the fuel injection tube 7° supplies fuel to a four-cylinder, four-stroke, in-line internal combustion engine, so that four injection conduits A, B, C are arranged at 900 angular intervals with respect to each rotation of the distribution member. , D must be supplied with fuel. This is illustrated in FIG.

The pump shaft is driven via rollers 30,
This roller is supported by a roller rond and slides along one or two cam surfaces of a mucam ring 31 that radially surrounds the pump piston. In this case, the pump piston and roller are moved by the compression spring 32 to the cam surface 33.
is maintained. This compression spring is compressed between the pump piston and the inner end face of the pump cylinder.

A valve 34 is arranged in the fuel supply conduit 22 and controls the amount of fuel injected. In this case, the valve is controlled by a control valve 35, which can be directly controlled as an electromechanical valve or can be constructed as a servo valve. Advantageously, the valve can be constructed in the same manner as disclosed by the prior art mentioned above, for a fast and precise switching process. However, depending on requirements, different configurations of piezoelectric or solenoid valves can be used. The fuel supply conduit 22 is supplied with fuel via a fuel storage tank 37 as well as a fuel transfer pump 36, the supply pressure being adjustable via a pressure control valve 38.

In FIG. 1, the pump piston in the second radial plane is shown offset by 45° relative to its actual position. The positions of the pump pistons in the first radial plane and the second radial plane are illustrated in FIG.

Furthermore, as is clear from FIG.
It is carried out at °. As is clear from FIG.
It corresponds to position 5.

In this case, it is assumed that the width of the cam surface 33 is designed so that the cam surface spans the roller 30 of the pump zero piston in both radial directions.

When the pump working shaft 10 rotates, the roller 30 moves against the cam surface 3.
3 and the pump piston is caused to reciprocate. In the case of an outward movement of the pump piston, the fuel supply conduit 22 is connected to one radial channel 19, so that fuel reaches the pump working chamber 14 in accordance with the control of the valve 34. Furthermore, for fuel delivery, the pump screws are moved inward by suitable cams on the cam surface. In this case, the connection to the fuel supply conduit 22 or at least the opening of the fuel supply conduit 22 is closed so that the first
The fuel displaced by the pump piston 12 of the pump is circulated through one of the distribution openings into one of the injection conduits controlled by the pump 1 and is forced to flow out at the P-family injection nozzle under injection pressure. Shall we go without C? .

During the suction stroke of the first pump, fuel is sucked in again and the next delivery serum is formed.

Due to the construction of the injection pump, the two pump piston pairs are located in different radial planes and are offset from each other, so that in the case of a fuel injection pump, in order to supply four cylinders with fuel, it is possible to A cam surface designed to provide 4 degrees of travel allows 8 travel strokes per revolution. Starting from FIG. 2, assuming that the fuel delivery into the injection conduit A via the second distribution opening 26 has ended, after a rotation of the camshaft through an angle of 45° in the clockwise direction, the Fuel injection into the injection conduit C takes place via one distribution opening 25 . This fuel quantity is conveyed via the first pump piston 12 according to FIG. After a subsequent rotation of 45°, the second distribution opening 2
6 into the injection conduit B, the second pump piston 13
The main injection quantity displaced by is conveyed. 9 more
After 00 revolutions, the second distribution opening 26 coincides with the injection conduit C, so that the main injection takes place in the injection conduit C via the second pump piston 13, which main injection is carried out through the first distribution opening 25. At 135° after the pre-injection via the injector, a color is supplied to a certain one and correspondingly also to all other injection conduits. The position of the cam 39 on the cam surface 33 in relation to the pump piston position is clearly illustrated in FIG. Furthermore, in FIG. 4, the cycle of the piston of the internal combustion engine is shown by the suction stroke and the compression stroke, and as is clear from FIG. , %i angle, therefore the pre-injection is performed at the start of the suction stroke and the main injection is immediately before the end of compression OT.

The main injection (particularly in diesel internal combustion engines) serves to ignite the charge in the combustion chamber of the internal combustion engine.

The main injection therefore defines the ignition point and must take place at a precise moment in terms of the combustion branch f relative to the top dead center of the pump piston. In this case, the main injection quantity in the fuel injection pump according to the invention must be increased so that ignition can take place. In this case, the pre-injection quantity must be designed in such a way that self-ignition of the compressed fuel-air mixture does not occur until the time of the main injection. Taking into account the above-mentioned limit conditions, a considerable quantity of fuel is already mixed well with the air charge of the combustion chamber during the intake phase and during the subsequent compression phase and is thus prepared for good combustion.

The same point of view can also be applied in the case of internal combustion engines with external ignition, which can avoid the intake throttle adjustment of the m-air intake, which has a disadvantageous effect, especially in part-load operation. Work with direct injection into the combustion chamber. The situation in such an internal combustion engine is similar to that of a diesel internal combustion engine. The preinjection according to the invention reduces soot production due to incomplete fuel combustion, increases the speed limit at which the internal combustion engine must be operated, and increases efficiency while maintaining permissible emission limits. Furthermore, a smoother combustion process with less noise can be obtained.

The amount of fuel injected via the fast-acting valve 34 is precisely controlled, in which case the fuel metering and control during the intake stroke as well as the effective delivery period control can be controlled by such a valve. . The intake valve in the case of a requisition period limit is opened during the suction stroke of the pump piston, so that the pump working chamber is completely filled with fuel, and during the subsequent conveying stroke of the pump piston, the closing of the valve causes the conveyance to begin. and the end of the conveyance is defined by the re-opening of the valve. Conveyance takes place with the cam sections thus flexed, and the injection can be controlled even after the start of floor conveyance or after the end of conveyance. A single valve in this described fuel injection system is sufficient to control the fuel injection by the first pump piston 12 as well as by the second pump piston.

Advantages of the invention The advantage of the fuel injection device according to the invention is that the fuel injection device can be constructed in a particularly simple manner and that a precise fuel pre-injection determined by an angle-related structure is achieved using a rapidly switching metering device. and -4· if the main fuel injections are obtained at predetermined angular intervals. In this case, by means of the cam configuration, the conveyance rates of the partial injections of the rapid transmission can be determined differently and optimized.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, in which FIG. 1 is a sectional view of a radial piston/fuel distribution injection pump, FIG. 2 is a sectional view of a distribution member of the injection pump according to FIG. 1, and FIG. FIG. 1 is a diagram showing the position of the pump male piston pair of the pump piston pair in the injection pump according to FIG. 1, and FIG. 4 is a diagram covering the injection range. 1... Caging, 2... Distribution/linda, 3... Distribution member, 4... End, 6, 8... Radial plane, 7.
9-, pump/cylinder, 10...pump drive shaft, 12.
13... Pump piston, 14.15... Pump working chamber, 16.17... Side passage, 18... Pressure conduit,
19.23.24...Radial passage, 20...Annular groove, 22...Fuel supply conduit, 25° 26・Distribution opening, 27・Injection opening, 28・Fuel injection valve, 30・・・
Roller, 31...Cam cylinder, 32...Compression spring, 3
3...Cam surface, 34...Valve, 35...Control@machine,
36... Fuel, % + conveyance pump 0.37... Fuel storage tank, 38... Compression control valve, 39 Cam.

Claims (1)

[Claims] 1. A fuel injection device for an internal combustion engine, comprising: at least one pump piston (12) forming a first pump working chamber (14) in a first pump cylinder (7); , second
in the pump cylinder (9) of the second pump working chamber (15
) forming at least one second pump piston (
13) and a rotationally driven distribution member (3) supported in a distribution cylinder (2), the first pump cylinder (7) of said pump cylinders being arranged in a first radial plane. (6) and a second pump cylinder (9) is located in the second radial plane (8), said distribution member being arranged between the first distribution opening (25) and the second distribution opening. (2
6) and an injection conduit (27) extending from the distribution cylinder, the distribution opening leading to the injection point of the internal combustion engine.
The distribution openings are aligned sequentially during the pump piston transport stroke during rotation of the distribution member, and the distribution openings are connected to the pressure conduits (23, 24).
) to a first pump working chamber (14) and a second pump working chamber (15), which pump working chambers have a fuel supply conduit (22) with a metering device (34). connectable via the first radial plane (
6) and a second radial plane (8), a cam ring (31) and a pump drive (10) are provided, said cam ring being radially directed towards the cam surface (33). and a cam ring (39) in synchronization with the rotation of the distribution member in order to reciprocate the pump piston by the pump drive device.
1) and the pump pistons (12, 13) are adapted to be moved in the rotational direction relative to each other, the mutual relationship between the cam of the cam ring and the pump piston and the mutual angular spacing (α) of the distribution openings In those types in which the actuation of the first pump piston is offset by this angular distance with respect to the actuation of the second pump piston, the first pump working chamber (14) and the second pump working chamber (14) A pump working chamber (15) is connected to a common pressure conduit (18) and a first passage (23) branching from this pressure conduit.
) to the first distribution opening (25) and at the same time to the second distribution opening (26) via a second passage (24) branching from the pressure conduit (18) and a common Fuel injection device for an internal combustion engine, characterized in that it can be connected via a suction conduit (19) to a fuel supply conduit (22) with a metering valve (24). 2. The angle is such that during the transport stroke of one pump piston, the other pump piston occupies the outermost radial position limited by the cam surface of the cam ring and one distribution opening is closed by the distribution cylinder. 2. The fuel injection device according to claim 1, wherein the distance (α) is selected. 3. Four injection conduits (27) extend from the distribution cylinder (2) at equal angular intervals and have distribution openings (25, 26).
3. The fuel injection device according to claim 2, wherein the angular distance (α) between the two is 135° from each other. 4. Any one of claims 1 to 3, wherein the metering valve (34) is electrically controlled at least indirectly by an electrical control machine (35). 1
The fuel injection device described in Section 1. 5. The control machine (35) controls each pump piston (1
2, 13), the fuel supply conduit (22) is opened during the suction stroke, closed at the beginning of the effective pump stroke and opened again to end the effective pump stroke. The fuel injection device according to any one of items up to item 4.