JPH089425Y2 - Fuel injection device for internal combustion engine with injection pump having several high-pressure outlets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device described in the superordinate concept of claim 1) for utility model registration.

The basic problem of this invention is to eliminate the difference in the supply amount of various injection valves by a simple and reliable means.

This problem is solved by the configurations described in the respective claims of the utility model registration.

That is, the present invention simply adjusts the supply amount of all the injection valves regardless of the cause of the difference in the supply amount that normally occurs by the independent adjustment of the supply amount adjusting devices attached to the individual high pressure outlets and the individual injection valves. Can be one common value.

In the past, devices in the form of pressure regulators with a piston acting against one spring in the frame of fuel injectors have been used (DE-OS2043914, F02M47 / 00), but these devices are used for fuel containers. Caused the influence of the back pressure of fuel. However, it is clear that these devices are not each independently attached to any one high pressure outlet of the pump.

 The drawings showing a plurality of embodiments will be described in more detail.

Referring first to FIG. 1, at 1 there is a high pressure outlet of the injection pump having a construction known and therefore not described. 2 is the housing. The high-pressure outlet 1 leads to a fuel conduit (not shown) which can be sealed and fixed by a sleeve nut 7 via a pressure valve 3 having a valve body 4, a closing spring 5 and a valve seat 6. The fuel conduit leads to a fuel injector of conventional construction. This injection valve opens when the fuel pressure is high enough to inject a predetermined amount of fuel.

Similarly, the high-pressure outlet 1 and the flow rate adjusting device 8 are flow-connected. The flow regulating device in this embodiment has its axis 9 oriented perpendicular to the axis 10 of the pressure valve 3. The flow rate adjusting device 8 has a base 11. The base body has holes of different diameters for accommodating the active part of the flow control device, and has an external threaded portion 12 for screwing into the notch of the housing 2. The active part of the flow regulator is a throttle valve 13 which is directed towards the high pressure outlet 1.
A magnetic control piston 14, which is mounted in a basic body 11 slidably in the direction of the shaft 9 of the device and forms a pressure chamber 15 with a throttle valve 13 whose volume can be changed, the pressure control chamber 14 by resisting the fuel pressure to the magnetic control piston 14. A compression spring 16 and a stopper 17 that try to slide 15 in the direction of contraction. The axial position of this stopper can be changed by an adjusting spindle 18 whose position can be fixed by a stop nut 19. The stopper 17 restricts the magnetic control piston 14 from sliding to the left in FIG. 1 and limits the maximum size of the pressure chamber 15.

As shown, the compression spring 16 is located between the disc spring 20 of the magnetic control piston 14 and the spring prestress plate 21 in the basic body 11 realized by the safety ring.

Magnetic control piston with increasing pressure in high pressure outlet 1
14 slides to the left in Fig. 1 to expand the pressure chamber and reduce the pressure. This expansion or reduction is influenced by the structure of the diaphragm 13 and the characteristic curve of the compression spring 16. Since each high-pressure outlet of the pump is provided with this type of adjusting device 8, the fuel supply amount can be adjusted to a predetermined value by the structure of the individual adjusting device for each injection valve.

As already seen, the stopper 17 limits the sliding of the magnetic control piston 14 in FIG. 1 to the left and the maximum volume of the pressure chamber 15. Therefore, by corresponding actuation of the adjusting spindle 18, the injection quantity or the supply quantity of the high-pressure outlet 1 can be individually controlled. Of course, this quantity adjustment is normally only possible, for example, at point A in the graph of FIG. 2 which shows the relationship between the load Q of the internal combustion engine and the speed n. The control of the feed rate can be carried out by the control device 8 both at higher rotational speeds, i.e. up to the C value, and also at lower rotational speeds, i.e. up to the B value, so that virtually in the entire operating range of the internal combustion engine. The difference between the feed rates of the individual high-pressure outlets is eliminated and the adjusting device 8 has, as it were, two other adjusting parameters.

The throttle 13 is constructed so that it does not work in the lower rotational speed region between points A and B of the graph shown in FIG. 2, but it has a pressure chamber 15 in the higher rotational speed region, ie between points A and C. The flow through to is limited. With a suitable selection of the throttle 13, i.e. with a constant flow-through value, a region of higher rotational speed, i.e. the second
It is possible to equalize the injection amounts of various high-pressure discharge ports even between points A and C in the figure.

In the lower rotational speed range, ie between points A and B, the throttle 13 does not work as described, so that it has virtually no effect on the flow into the pressure chamber 15. Also in this case, "equal supply",
That is, the magnetic adjustment device 8 provided side by side with the various high pressure outlets in order to guarantee equalization of the supply amount of the various high pressure outlets.
A compression spring having various elastic constants and / or various initial stresses is used, and elastic initial stress plates 21 having different thicknesses can be inserted to adjust the initial stress. As a result, the magnetic control piston 14 is later sensitive at a low rotational speed n where the injection pressure is low and the injection pressure gradient is flat, that is, the leftward movement of the magnetic control piston in FIG. 1 starts later.

It should be noted here that the relationship and control method described above with reference to FIG. 2 also apply to the embodiment shown in FIGS. 3 and 4.

In the embodiment shown in FIG. 1, the pressure valve 3 and the magnetic adjustment device 8 are separate structural units and are screwed into different notches in the pump housing 2, but FIG. 3 shows the pressure valve 30 and the supply amount adjustment device. It shows the first possibility of making 31 into one structural unit, which is screwed into a unique notch in the pump housing 32. The pressure discharge port 33 communicates with this cutout portion. Cap with screw thread 34
By means of 35 several base parts 36, 37, 38 are kept at least in the integrated state of the unit, these base parts and the cap 35 also being in line with one another for accommodating the active part of the pressure valve 30 and the regulating device 31. And has an axial cutout or hole. At the outer center, there are different holes for forming fuel supply lines 39 in various parts, which lead to fuel pipe connections 40 (not shown) leading to the respective injection valves. The fuel supply line 39 almost bypasses the original regulating device 31. This adjusting device has, as its essential components, a throttle 41 directed toward the pressure valve 30, a magnetic control piston 42 axially slidably supported, a throttle 41 and a magnetic control piston.
A stopper 46 whose axial position can be set by a pressure chamber 43, a pressure spring 44, and an adjusting screw 45 is provided between the pressure chamber 43 and the pressure sensor 42. 47 is a packing. The supply regulator 31 is only related to the fuel pressure via a line 48 leading to the outlet of the pressure valve 30.

The pressure valve 30 has the same structure as that of FIG. That is, as essential structural elements, there is a slidable piston 50 which is lifted from its valve seat by resisting the action of a pressure spring by fuel pressure, and in this embodiment two plates 52 for setting elastic initial stress. .

In this embodiment as well, the regulating device 31 operates according to the fuel pressure at that time, but at the outlet of the pressure valve 30 the axial sliding of the magnetic control piston 42 and a throttle of suitable construction as shown in the graph of FIG. By means of 41 and the control of the current capacity of the pressure chamber 43 by the use of the spring 44, it is possible to set the planned supply quantity over the entire speed range of the internal combustion engine.

FIG. 4 shows the economically cheapest pressure valve and feed rate regulator. Also in this example, the unit screwed into the notch of the pump housing 60, as it were, on the extension of the high-pressure outlet 61 has two base parts 64 and 65 held by a cap 62 carrying a screw thread 63. The cap 62 carries a threaded connection 66 at the outer end of the pump housing 60 for a fuel supply pipe (not shown) leading to the injection valve.

The pressure valve has a valve body 69 that slides from the fuel pressure to the start of the action of the stopper 68 against the action of the pressure spring 67. The valve body releases the flow path so that the fuel reaches the supply pipeline 71 after being lifted from the valve seat 70. This supply line reaches the connecting portion 66, where there is a throttle 72, a magnetic control piston 73, and a spring which attempts to slide this magnetic control piston in the direction of contraction of the pressure chamber between the throttle 72 and the magnetic control piston 73. It leads to the inlet of a dosing device having 67. Therefore, this spring is also common to the magnetic control piston 73 and the valve body 69 of the pressure chamber.

As described above, the present invention makes it possible to set the same supply amount for all the injection valves connected to one injection pump.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment in which a pressure valve and a supply amount setting device are separate bodies, FIG. 2 is a load / rotation speed graph used for explaining various components of the setting device, and FIG. 3 is pressure. 4 is a longitudinal sectional view of the structure in which the valve and the setting device are combined into one structural unit,
The figure shows another embodiment in which this united structure is extended to the compression valves and setting devices of the individual structural elements. Reference numeral 1 in the figure: 1 high-pressure discharge port, 2 ... injection pump housing, 8
...... Supply amount setting device, 13 ...... Throttle, 14, 73 ...... Magnetic control piston, 15 ...... Pressure chamber, 16 ...... Spring, 17 ...... Stopper, 30 ...... Pressure valve, 31 ...... Setting device, 33 ...... High pressure outlet, 39 ...... Fuel supply line, 62 …… Cap, 63 …… Screw screw, 64,65 …… Base part, 67 …… Compression spring, 69…
… Valve, 71 …… Fuel supply line.

Claims (7)

[Scope of utility model registration request] 1. In a fuel injector for an internal combustion engine, in particular a diesel engine, having an injection pump with several high-pressure outlets for each injection valve, each high-pressure outlet (1) being independently adjustable in volumetric flow control. A magnetic control piston (14), which is fluidly coupled to the device (8) and on which each volume flow rate adjusting device (8) is slidably supported, forms a compression chamber (15) in the direction of the high pressure discharge port (1). Adjusting the throttle (13) and the piston (14), which are pre-mounted on the magnetically controlled piston and are independently configured for each injection valve, preferably limit the sliding of the compression chamber (15) in the direction of expansion. A fuel injection device, characterized in that it has a spring (16) which starts from a possible stopper (17) and tries to push in the direction of contraction of the compression chamber (15). 2. The throttle (13) is configured to limit the flow through only when the engine speed range (A-C) is higher, and the engine speeds are medium and low (A). -B)
Device according to claim 1), wherein different spring constants of different setting devices (8), in particular springs (16), are used to set the same supply in this case, or different elastic initial stresses are set. 3. Device according to claim 1) or 2), wherein each setting device (8) forms one independent component unit. 4. The device according to claim 3, wherein at least the individual setting devices (31) are grouped together with the pressure valve (30) of the side-by-side high-pressure outlet (33) into one structural unit each. 5. The structure unit according to claim 3, wherein an inlet of the setting device (31) is connected to a discharge side of the pressure valve (30) and at least a fuel supply line (39) circulating the setting device is connected. apparatus. 6. Pressure chamber formation in which a pressure valve has a valve body (69) axially movably supported in a structural unit and a setting device axially movably supported in a structural unit. A compression spring (6) having a magnetic control valve (73) for use as a closing spring for the pressure valve in the axial direction or a spring for loading in the pressure chamber contraction direction as the magnetic control valve (73).
Surrounding 7), at least one fuel supply line (71) exits from the outlet of the pressure valve, and this fuel supply line is connected to the inlet of the setting device arranged on the side opposite to the pressure valve. The device according to claim 4). 7. A structural unit having several axially continuous base body parts (64, 65) held by a cap screw (62) with a threaded thread (63), these base bodies The parts are the components of the pressure valve and setting device (67, 69, 72, 7
3) has the same row of axial notches for accommodating and also has the same row of partial line for forming the fuel supply line (71) at the outer center, and the structure of the basic body part (64, 65) is 7. Device according to claim 5) or 6), which enables the use of the pressure valve and the components of the setting device before the assembly of the basic body.