|Title of Invention||
FUEL INJECTION VALVE FOR HIGH-PRESSURE INJECTION
|Abstract||Fuel injection valve for high-pressure injection Abstract The proposal is for a fuel injection valve (1) which is provided for the purpose of high-pressure injection on self-ignition internal combustion engines and has a solenoid valve (23) for controlling injection Provided for the purpose of activating this solenoid valve is a control circuit which is divided into a first circuit component and second circuit components (31). The latter are arranged separately from the first circuit component, which serves jointly for the control of a plurality of injection valves, on each individual injection valve. The housing is snapped onto the fuel injection valve and fuel flows through its interior for the purpose of cooling.|
|Full Text||The invention taKes as its starting point a tue± injection valve for high-pressure injections of the generic type of Patent Claim 1. One such fuel injection valve, knov/n from US Patent 4,972,997, is supplied with fuel by a high-pressure accumulator. Control of injection is performed electrohydraulically here, fuel being fed under pressure to a control space by the high-pressure fuel source. By means of this control pressure, the valve member of the fuel injection valve is held in the closed position since the control surface subjected to the control pressure is larger than the pressurized surface on the fuel injection valve. The control space is continuously connected to the high-pressure fuel source via a first restrictor and can be relieved via a second restrietor, which is controlled by a solenoid valve. As soon as the solenoid valve opens the second restrictor, the control space is relieved and the pressure on the pressure surfaces of the valve member of the injection valve is sufficient to move the valve member into the open position, allowing injection to take place. If the second restrictor is closed again by the solenoid valve, the valve member is moved back into the closed position by virtue of the increase in pressure in the control space. In this arrangement, the solenoid valve is secured on the housing of the fuel injection valve, coaxially to the axis of the valve member of the injection valve, and has a plug-in connection for the supply of power to the electromagnet of the solenoid valve, and a relief line, which leads away from the electromagnet and via which the fuel spill quantity can flow off to a relief space at the second restrictor, is furthermore provided.
Such fuel injection valves are switched by means of an electric control system in such a way that high-pressure fuel is fed to the internal combustion engine at the required point in time and in the required quantity. The electric control circuit is here arranged centrally
in the vicinity of the fuel injection valves, of which in each case one is provided per cylinder of the associated internal combustion engine. This arrangement has the disadvantage that long connecting lines which are sub-jected to high currents and generate interference fields have to be taken to the individual fuel injection valves. Furthermore, because of the power made available for the rapid opening and closure of the solenoid valves, there must be adequate provision for dissipation of the heat generated in the electric control circuit. This is associated with an additional outlay.
Advantages of the invention
In contrast, the fuel injection valve according to the invention with the features of the characterizing clause of Patent Claim 1 has the advantage that the electric control circuit is divided into a first circuit component and into second circuit components, which are each provided directly on the fuel injection valve and contain the control system for the power supply to the electromagnet. In particular, it is advantageous, in accordance with Patent Claim 2, for the elements of the circuit which contain the power components and capacitors of the electric control circuit to be provided in the second circuit component. The heat generated, in particular, in the power components, capacitors, output stages and diodes is here distributed between the individual injection valves and can be optimally dissipated there without further expenditure for control of cooling devices. In particular, the provision of long lines subjected to high current is avoided. The power losses due to voltage drop are reduced and plug-in connections to be subjected to high loads are also avoided since the high currents occur only in the second circuit component and are there passed directly over the shortest possible connecting line to the magnet. In addition, the short lines have the further advantage that interfering radiation is reduced, something which can affect the electric circuit of the control system, in particular. The first
part of the control circuit is in this case reduced to the signal processing components of the circuit, which are not disturbed by reactive effects due to the power component required in each case for activating the solenoid valve.
Accordingly the present invention provides a fuel injection valve for high-pressure injection into combustion spaces of, in particular, self-ignition intemal combustion engines, with a solenoid valve by means of which the connection of the fuel injection valve to a high-pressure fuel source is controlled atleast indirectly by an electric control system, characterized in that the electric control system has a control circuit which is divided into a first, common circuit component, which controls a plurality of fuel injection valves, and into second circuit components, which second circuit components are each located directly on a respective fuel injection valve in order to control the power supply to the electromagnet of the solenoid valve.
Description of an exemplary embodiment
The drawing illustrates a longitudinal section through a fuel injection valve for high-pressure injection with an integrated solenoid valve which has the second circuit component according to the invention as an additional integrated part. In the housing 1 of the fuel injection valve there is a valve-closing member 2 with a conical sealing surface 3 that comes to rest against a conical valve seat 4 from which there lead off injection holes 5. The valve member is then pushed in the closing direction onto the valve seat 4 by a compression spring 7. Provided in the intermediate region of the valve- closing member 2 is a pressure space 9 within which a pressure surface 10 facing in the opening direction of the valve-closing member is exposed to the pressure prevailing there, this pressure being fed via a high- pressure inlet line 11 to the pressure space 9. The high- pressure inlet line is connected to a high-pressure accumulator (not shown) by way of a high-pressure connection 12 which leads away transversely to the longitudinal axis of the injection valve. Also engaging on the valve- closing member 2, coaxially to the compression spring 7, is a tappet 14, the end 17 of which delimits a control space 18 in an insert 15 in the housing 1 of the injection valve. This control space has, from the high-pressure connection 12, an inlet with a first restrictor 19 and an outlet to a rehef line 21 with a second restrictor 20, which is controlled by a valve member 22 of a solenoid valve 23. The solenoid valve 23 has a spring 24, which acts in the closing direction, and an armature 25 on the valve member, the said, armature being attracted by the electromagnet 26 of the solenoid valve when its coil 27 is excited and hence opening the second restrictor 20.
The housing 29 of the solenoid valve is secured on the housing 1 of the injection valve, coaxially to the position of the tappet 14 and the valve-closing member 2, means of union nut 30.
According to the invention, a housing 32 of a circuit component is now placed on the end of the housing 29 of the solenoid valve. As illustrated schematically in section, this housing contains parts of the control circuit as the second circuit component 31 of the control circuit. The majority of the control circuit operations, in particular signal processing, takes place in a first circuit component (not shown specifically here) of the electric control system, while the power components and energy storage devices, in particular, are contained as the second circuit component 31 in the second circuit component within the housing 32. The housing 32 also contains the electrical terminal 33 with power supply and signal supply from the first circuit component. The housing 32 enclose an interior space 34 which accommodates the circuit components mentioned and through which the fuel flows, this being led away to the relief line 21 through the solenoid valve 23 to relieve the control space 18. In this arrangement, the fuel flows around the electromagnet and, downstream of the latter, also around the second circuit component 31. An outlet stub 36 which leads via the relief line 21 to a fuel tank is arranged on the housing 32 for the purpose of carrying away the inflowing fuel. In this way, the electromagnet and the second circuit component 31 are intensively cooled.
The housing 32 is preferably composed of plastic or insulating material with additional elastic properties such that the housing can be snapped leaktightly onto the housing 29 of the solenoid valve. This ensures that it ic easy to replace.
1. A fuel injection valve for high-pressure injection into combustion spaces of,
particular, self-ignition internal combustion engines, with a solenoid valve (23) by
means of which the connection of the fuel injection valve to a high-pressure fuel
source is controlled at least indirectly by an electric control system, characterized in
that the electric control system has a control circuit which is divided into a first,
common circuit component which controls a plurality of fuel injection valves, and
into second circuit components (31), which second circuit components are each
located directly on a respective fuel injection valve in order to control the power
supply to the electromagnet (26) of the solenoid valve (23).
2. The fuel injection valve for high-pressure injection as claimed in claim 1, wherein the second circuit components (31) essentially have power components and storage elements of the electric control system and are arranged in a control housing (32) between the solenoid valve (23) and an electrical terminal (33) of the injection valve.
3. The fuel injection valve for high-pressure injection as claimed in claim 2, wherein the control housing (32) also has the plug-in connection (33) for connection to the first circuit component and is placed on a housing (29) of the solenoid valve.
4. The fuel injection valve for high-pressure injection as claimed in any one of claims 2 or 3, wherein a relief line (21) leading away from the solenoid valve is passed through the control housing (32).
5. The fuel injection valve for high-pressure injection as claimed in claim 4, wherein the control housing (32) is of a plastic material which is snapped, in particular in an elastically sealing manner, onto the housing (29) of the solenoid valve.
6. The fuel injection valve for high-pressure injection as claimed in claim 2, wherein the solenoid valve (23) is connected to a housing (1) of the fuel injection valve, extending it in the axial direction, and the control housing (32) is in turn secured on the housing (29) of the solenoid valve, extending it in the axial direction.
7. A Fuel injection valve for high-pressure injection substantially as herein described with reference to the accompanying drawings.
|Indian Patent Application Number||2356/MAS/1996|
|PG Journal Number||30/2009|
|Date of Filing||23-Dec-1996|
|Name of Patentee||ROBERT BOSCH GMBH|
|Applicant Address||POSTFACH 30 C2 20, 70442 STUTTGART|
|PCT International Classification Number||F02M51/00|
|PCT International Application Number||N/A|
|PCT International Filing date|