EP0813652B1 - Fuel injection device for auto-ignition internal combustion engines - Google Patents

Description

The invention relates to a fuel injection device for a self-igniting Internal combustion engine with a rotatable in a crankcase mounted crankshaft, at least one carrying a piston Connecting rod is articulated, with the piston in one of a cylinder head covered cylinder is movable, still the fuel injector at least one high-pressure pump that promotes fuel which has the fuel in a supply store (common rail) promotes the at least one metering valve with at least one Injector is connected.

Such a fuel injection device is from the company brochure from MAN "Electronic injection safe for future fuel qualities" known from 4/1980. The one described in this document Fuel injection device is designed for use in an Two-stroke process working ship diesel engine. This fuel injector has a fuel pressure accumulator, which the under approximately a constant fuel pressure of approx. 700 bar electronically controlled for supply to the individual injection valves can be removed. The entire control device is like this built that this in addition to the electronic control Working medium in the form of a hydraulic fluid needed with which the individual Valves and actuators are operated. At least they are Approximately to scale components "cylinder unit and High pressure pump "arranged far apart, so that together with that arranged elsewhere on the internal combustion engine Fuel pressure accumulator long connecting lines for the under Pressurized fuel are necessary. This makes the system overall hydraulically soft, so that basically with the fuel injection system shown achievable advantages cannot be achieved.

A fuel injector with one in the crankcase a self-igniting internal combustion engine high pressure pump according to the preamble of claim 1 is from DE-C-4 340 311.

The invention has for its object a fuel injection device to provide for a self-igniting internal combustion engine that is hydraulic is stiff and compact.

This object is achieved by the features according to the characterizing part of claim 1.

In a development of the invention, the high-pressure pump is housed in the Crankcase inserted. This training has the advantage that on the one hand a separate housing for the high pressure pump is saved and on the other hand, the overall system becomes mechanically stiffer because gained space by eliminating a separate pump housing is used for reinforcement of the crankcase in this area can be exploited. Also fall through the elimination of the separate Pump housing the otherwise necessary fits or connections away from the pump housing to the crankcase, which is at least affects the processing effort.

In a further development of the invention, the camshaft has cams for actuating the gas exchange valve on and is over a single tooth mesh from the crankshaft driven. This training is especially at a In-line internal combustion engine is advantageous because it creates a separate camshaft to drive the high pressure pump is saved. For the rest is the camshaft advantageously designed so that at least in some areas three cam sections directly next to each other along the camshaft arranged and bordered by bearings. This will be two Cam sections for controlling the gas exchange valves (inlet and outlet) needed during the third cam section to actuate the high pressure pump is used. By enclosing these sections of Bearing points the camshaft is further stiffened, so that from a bend or twisting of the camshaft from possible sources of error are almost eliminated. The bearing points can also be provided and the intermediate cam areas are seamless, i. H. without To let punctures merge. This minimizes Space requirement made another contribution to a rigid camshaft. By driving the camshaft via a single meshing of the crankshaft will twist the camshaft relative to the Crankshaft in known camshaft drives over several Gears, timing belts or chains occur, and the reachable Reduce peak pressure or impair precise control, avoided.

In a development of the invention, the camshaft for driving the High pressure pump two, three or more on the circumference of the camshaft distributed cams on. This training has the advantage that with a single Rotation of the camshaft the high pressure pump several times Can fill supply storage. In contrast to an injection pump element the filling of the high pressure accumulator is independent from the respective work cycle to which the injection pump element is put together must be aligned with the injector. Furthermore the flanks of the cams can be redesigned to the extent that the steep flanks of injection pump elements are defused because - as stated before - no steep for high pressure pumps Pressure increase, as with injection pump elements to meet specified Injection laws are required. Rather, the nocks regarding the load of the high pressure pump and the whole Systems can be optimized. The number on the circumference of the camshaft Arranged cams therefore depend on the particular circumstances for the internal combustion engine (number of cylinders, size of the high pressure pump etc.).

In a development of the invention, two or more high-pressure pumps distributed along the internal combustion engine. This also applies to this previously said that here an optimization according to the parameters mentioned above (Number of cylinders, delivery volume of the high pressure pump, etc.).

In a further development of the invention, the supply memory extends along at least one row of cylinders of the internal combustion engine. Thereby is in cooperation with the close arrangement already described above and alignment of the high pressure pump towards a cylinder head the associated injector another contribution to a stiff System supplied, because of this arrangement the length of the connections from high pressure pump to supply storage and from supply storage to the individual injectors is reduced as much as possible. If the internal combustion engine is designed in a V-type, the invention can be used a single supply storage in the V space between be arranged in the two rows of cylinders, this training offers especially for small V-angles, i.e. if the two rows of cylinders are relatively closely aligned. Otherwise it is in Of course, the scope of the invention also provides two supply lines to be provided, in which case one supply memory each Row of cylinders is assigned. The supply store (s) can advantageously also be integrated in the cylinder head.

In a further development of the invention, the supply memory with the High pressure outlet of the high pressure pump connected via a short pressure line. Through this training - as indicated above - that the losses or pressure fluctuations that occur in long pressure lines result, are virtually excluded. It is in a further embodiment the invention provided that the supply memory of two or more high pressure pumps is carried. This training is particularly useful if, for example, two or three high-pressure pumps are provided, which are arranged distributed along the internal combustion engine are, for example at the two ends and in the middle of one Row of cylinders, then the supply storage directly on this High pressure pumps is attached. This can, if necessary, on a separate attachment of the supply memory on the internal combustion engine be, so that in addition, for example, a complete Unit consisting of high pressure pumps and supply storage can be preassembled is and finally assembled as a unit on the internal combustion engine becomes.

In a further development of the invention, the metering valve is on the supply store arranged or in a further development of the invention directly on the injector. Here a solution will be chosen that the best meets the respective requirements. So one is right on Injection valve arranged metering valve capable of the injection valve amount of fuel to be metered in terms of quantity and timing to control precisely, because between the metering valve and the injection valve there are no lines adversely affecting metering are. On the other hand, one arranged on the supply store Metering valve in turn the possibility of a very compact and also unit to be manufactured or pre-assembled from a high pressure pump, Provide supply storage and metering valves. Furthermore is due to the omission of the metering valve in the area of the cylinder head the overall height is reduced, which is hardly available in many applications stands. In an embodiment of the invention, the metering valves at least largely be solenoid valves that are already in use solenoid valve-controlled injection systems (MV systems from KHD) Find use. These are systems in which the Injection pump element is provided with such a solenoid valve, the one connected to an injection pump element or solenoid valve The fuel quantity to be injected controls. For actuation the metering valves can also use piezo switching elements become.

In a development of the invention it is provided that in the supply line prevailing pressure via a hydraulic and / or electrical Transmission acts on an actuator, which then the Control rod adjusting inclined edge actuated. It can be done in the simplest Execution may be provided, for example, the supply line to be provided at the end with a pressure transmission line, which in the actuator designed as a pressure converter opens and the Control rod for adjusting the inclined edges controls. Alternatively, it can but also be provided, the pressure in the supply storage electrically for example, using sensors and measuring them Use the value to adjust the control rod. This can be done, for example a corresponding servomotor, for example a stepper motor be used. In the same way it is also possible the electrical signals for controlling a hydraulic adjustment device the control rod.

In a further development of the invention, the actuating device is the front end Internal combustion engine, in particular arranged instead of a speed controller. This training has the advantage that no additional space is required on the internal combustion engine to accommodate such an actuating device is required. Rather, the internal combustion engine as a whole be designed so that it can be used with a conventional Injection system with or without the solenoid valve technology described above is equipped or with the system according to the invention with a supply storage.

Finally, in a further development of the invention, the actuating device is provided in an opening of the crankcase instead of an injection pump element to use. As previously stated, in generally not all available in a conventional internal combustion engine Openings for injection pump elements are required because of the generation the high pressure in the supply storage fewer high pressure pumps required are. It can then be used in an unused Opening the actuator. This actuator is then basically constructed similar to a high-pressure pump, whereby this Actuator then of course no drive from the camshaft having. Rather, it becomes "quasi backwards" from the supply memory hydraulically and / or electrically transmitted pressure the control rod to control the flow rate of the other high pressure pumps transfer. This training represents a particularly compact one Execution, this device also as a carrier for the Supply storage used according to one of the previous training courses can be.

Of course, the fuel injection device according to the invention can also be realized with conventional plug-in pumps. Here is the injection pump element or the high pressure pump in its own pump housing arranged. This pump housing can predominantly in Crankcase of the internal combustion engine or partly in and partly on the same be arranged and an external fuel supply in contrast to the fuel supply advantageously arranged in the crankcase have in the previously described training. This arrangement offers the advantage that the high pressure chamber of the high pressure pump interacting particularly closely with the supply store to that Injector can be used. Besides, the danger of Fuel heating and fuel leakage inside the crankcase the external fuel supply avoided.

Further advantageous embodiments of the invention are the description of the drawing can be seen in the embodiments shown in the figures the invention are described in more detail.

Figur 1:

eine schematische Seiteneinsicht einer Brennkraftmaschine mit der erfindungsgemäßen Kraftstoffeinspritzvorrichtung,

Figur 2:

eine schematische Stimansicht einer Brennkraftmaschine mit der Kraftstoffeinspritzvorrichtung, wobei der Versorgungsspeicher an der Zylinderreihe befestigt und das Zumessventil auf dem Einspritzventil angeordnet ist und

Figur 3:

eine schematische Stimansicht der Brennkraftmaschine, wobei der Versorgungsspeicher auf der Hochdruckpumpe befestigt und gleichzeitig das Zumessventil auf dem Versorgungsspeicher angeordnet ist.

Show it:

Figure 1:

2 shows a schematic side view of an internal combustion engine with the fuel injection device according to the invention,

Figure 2:

a schematic end view of an internal combustion engine with the fuel injection device, wherein the supply memory is attached to the row of cylinders and the metering valve is arranged on the injection valve and

Figure 3:

a schematic end view of the internal combustion engine, wherein the supply store is attached to the high pressure pump and at the same time the metering valve is arranged on the supply store.

The self-igniting internal combustion engine shown schematically in Figure 1 In the exemplary embodiment, 1 has 6 cylinders which are arranged in one Row are arranged. The internal combustion engine 1 is basically conventional constructed and initially has a crankshaft 2, which in the crankcase 3 (see also Figures 2 and 3) is mounted. Farther a camshaft 4 is mounted in the crankcase 3, the camshaft 4 driven by the crankshaft 2 via a single tooth engagement is. For this purpose, the crankshaft 2 and the camshaft are located on the front side 4 gears 5a, 5b arranged, which are designed so that the camshaft 4 is driven at half the crankshaft speed. The camshaft 4 has gas exchange valve cams assigned to each cylinder 6a, 6b, to which cams 7a, 7b, 7c continue to connect same axial area of the camshaft 4 lying on the circumference of the Camshaft 4 are arranged distributed (Figures 2 and 3). Framed the gas exchange cams 6a, 6b and the cams 7a, 7b, 7c of bearing points 8a, 8b, which are directly on the gas exchange valve cams 6a and connect the cams 7a, 7b, 7c. The transition from Bearing points 8a, 8b to the individual cam areas without transition, i.e. essentially without the camshaft 4 weakening punctures between the individual cam areas. Shown in Figure 1 are otherwise only the bearing points 8a, 8b with the intermediate cam areas for a cylinder, just like the crankshaft 2 in only one Sub-area is shown. Of course, both components extend in the illustrated embodiment over the entire length of the internal combustion engine 1.

The roller tappet 9 runs on the cams 7a, 7b, 7c of the camshaft 4 a high pressure pump 10 and drives a pump plunger 18 which Fuel in a extending along the internal combustion engine 1 Supply store 11 (common rail) via a short pressure line 12 promotes (Figures 1 and 2). The high pressure pump 10 is of its basic Structure of an injection pump element with an inclined edge control. That is, the aforementioned pump plunger 18 has one Inclined edge 17 which, depending on the rotation of the pump plunger 18th cooperates with a drain hole. This twist can the delivery rate of the high pressure pump 10 between a zero delivery rate and a maximum delivery rate can be varied. The is adjusted Pump plunger 18 from a control rod 13, which in turn extends along of the internal combustion engine 1 extends.

When operating the internal combustion engine, the high-pressure pump now 10 continuously promoted fuel in the supply store 11. From this supply memory 11 branch according to the respective Number of cylinders of the internal combustion engine 1 from injection lines 14, 14 ' ultimately connected to an injection valve 15, 15 '. It is according to the embodiment of Figure 2, the supply memory 11 arranged and attached to the crankcase 3 or the cylinder bank. The injection lines branching off from this supply store 11 14 open into an arranged on the injection valve 15 Metering valve 16. This metering valve 16 is, for example, one of an electronic control unit designed to control a solenoid valve, the fuel flow according to the respective operating parameters controls from the injection line 14 into the injection valve 15.

In contrast to the embodiment shown in Figure 2 is in the embodiment 3, the supply memory 11 directly on the High pressure pump 10 attached. Furthermore, the metering valve 16 is in turn arranged directly on the supply memory 11 so that the injection line 14 'opens directly into the injection valve 15'. Of course is also possible in this embodiment, to arrange the metering valve 16 directly on the injection valve 15. Due to the illustrated design of the internal combustion engine with a supply memory 11 is in almost all operating conditions the supply storage of the fuel under an approximately the same Pressure of, for example, 1,400 bar is available and can be via the metering valves 16 the injectors in almost any controlled manner 15, 15 'are supplied. This allows the running behavior the internal combustion engine, but especially the exhaust gas emissions and noise emissions and also fuel consumption.

The quantity to be delivered by the high-pressure pumps 10 is controlled - as previously stated - by the bevelled edge 17 Pump plunger 18, which is adjusted by the control rod 13. Here there is the axial displacement of the control rod causing the adjustment 13 by an actuating device in the form of a pressure converter 19, which is arranged according to Figure 1 on the front side of the internal combustion engine is. This pressure converter 19 is connected to the supply store via a control line 20 11 connected. This system is coordinated that when the pressure in the supply memory 11 drops, this falling pressure via the control line 20 into the pressure converter 19 is forwarded and accordingly the pressure converter 19 the control rod 13 towards an increase in the delivery rate of the high pressure pumps 10 adjusted. This is an automatic in a simple manner Pressure control in the supply store 11 possible. As part of The invention also provides for the pressure in the supply store 11 to be detected, for example, by pressure sensors and these Apply signals to the pressure converter 19. Then there is the Pressure converter 19 preferably as an electrically actuated control element educated. In the context of the invention it is in particular as in the general description described - provided the actuating device in the form of a pressure converter 19 'in addition to a high pressure pump 10 similar to this in the crankcase 3 of the internal combustion engine. This actuating device is then basically analogous to a high-pressure pump 10, but has no roller tappet 9 on. Rather, that of the control line 20 'of the actuating device transmitted pressure in the supply memory 11 only for adjusting the Control rod 13 used.

Claims (14)

1. A fuel injection device for an auto-ignition internal combustion engine comprising a crankshaft mounted for rotation in a crankcase and pivoted to at least one connecting rod bearing a piston, wherein the piston is movable in a cylinder covered by a cylinder head, wherein also the fuel injection device has at least one fuel-delivering high-pressure pump which is inserted in the crankcase (3) and disposed at the high pressure side at a region near a cylinder and driven on the drive side by a camshaft (4) and delivers fuel to a supply reservoir connected by at least one valve to at least one injection valve,
   characterised in that the valve is a metering valve (16) which, depending on the relevant operating parameters, controls the flow of fuel into the injection valve (15) so that the pressure in the supply reservoir (common rail) (11) is used to control the high-pressure pump (10), and the high-pressure pump (10) comprises a cylinder and a pump piston movable therein and having a sloping edge and in operative connection with a control rod (13) mounted in the crankcase (3) for controlling the quantity.
2. A fuel injection device according to claim 1, characterised in that the high-pressure pump (10) is inserted in the crankcase (3) without a case of its own.
3. A fuel injection device according to any of the preceding claims, characterised in that the camshaft (4) has cams (6a, 6b) for actuating the gas change valve and is driven by a single tooth engagement by the crankshaft (2).
4. A fuel injection device according to any of the preceding claims, characterised in that the camshaft (4) has two, three or more cams (7a, 7b, 7c) distributed around the periphery of the camshaft (4) for driving the high-pressure pump (10).
5. A fuel injection device according to any of the preceding claims, characterised in that two or more high-pressure pumps (10) are distributed along the internal combustion engine (1).
6. A fuel injection device according to any of the preceding claims, characterised in that the supply reservoir (11) extends along at least one row of cylinders of the engine (1).
7. A fuel injection device according to any of the preceding claims, characterised in that the supply reservoir (11) is connected to the high-pressure outlet of the high-pressure pump (10) via a short pressure line (12) and the high-pressure pump or pumps (10) each have a pressure-holding valve.
8. A fuel injection device according to any of the preceding claims, characterised in that the supply reservoir (11) is supported by two or more high-pressure pumps (10).
9. A fuel injection device according to any of the preceding claims, characterised in that the supply reservoir (11) is incorporated in the cylinder head (3a) of the engine (1).
10. A fuel injection device according to any of the preceding claims, characterised in that the metering valve (16) is disposed in the supply reservoir (11).
11. A fuel injection device according to any of the preceding claims, characterised in that the metering valve (16) is disposed on the injection valve (15, 15').
12. A fuel injection device according to any of the preceding claims, characterised in that the pressure in the supply reservoir (11) acts via a hydraulic and/or electric transmission on an adjusting device (19) which, via the control rod (13) actuates the sloping edge or edges (17) of the high-pressure pump or pumps (10).
13. A fuel injection device according to any of the preceding claims, characterised in that the adjusting device (19) is disposed at one end face of the engine (1) more particularly instead of a speed regulator.
14. A fuel injection device according to any of the preceding claims, characterised in that the adjusting device (19') is disposed in an opening in the crankcase (3) instead of an injection pump element.

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