Fluid sprinkling – spraying – and diffusing – Unitary injection nozzle and pump or accumulator plunger
Reexamination Certificate
2001-06-12
2003-09-30
Douglas, Lisa A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Unitary injection nozzle and pump or accumulator plunger
C239S092000, C239S096000
Reexamination Certificate
active
06626369
ABSTRACT:
RELATED ART
The present invention relates to an injection device with an injection valve, a valve device for controlling the injection, and a setting element for operating the valve device. The present invention further relates to a method for injecting fluid in which a setting element is activated, a valve device is operated by the setting element, and an injection valve is opened.
A generic device and a generic method are made known, for instance, in European Patent No. 0 562 046 B1. The basic requirement on such a system is that fuel injection be carried out using the highest injection pressure possible. High injection pressure has positive effects on the performance of an engine; for instance, it reduces emissions and fuel consumption. To achieve high injection pressure, a pressure booster can be provided which converts a primary pressure, e.g., provided by a pressure accumulator, into the desired high injection pressure via hydraulic pressure intensification. By making a suitable selection of surfaces of the pressure booster to which force is applied and the counterforces of elastic materials, a suitable pressure increase can be set.
To control injection, a valve device is provided which is operated by a setting element, e.g., a solenoid valve or a piezoactuator. This valve device serves to feed the primary pressure to be intensified to the pressure booster, to perform depressurization, and to refill the pressure booster after the pressure has been increased and, consequently, injection has taken place via the injection valve.
The related art uses a 3/2 valve as the valve device. In an initial control state of the 3/2 valve, the flow of fuel between a fuel inlet and the primary side of the pressure booster is blocked. On the other hand there is a connection between the primary side of the pressure booster and the leakage system. If the setting element of the injection device is now operated, the 3/2 valve switches to a transition state in which a connection exists between the fuel inlet and the primary side of the pressure booster as well as between the primary side of the pressure booster and the leakage system. When the setting element is operated further, the second control state of the 3/2 valve is accepted, in which the connection of the primary side of the pressure booster with the leakage system is blocked, but the connection between the fuel inlet and the primary side remains open. When the pressure booster is depressurized or refilled, the 3/2 valve moves through the control states described in reverse sequence.
In the solution of the related art described, the fact that high leakage rates occur proved especially problematic. They degrade the effectiveness of the injection system. Furthermore, a 3/2 valve is only conditionally suited for high-pressure applications, especially with regard for manufacture and sealing.
A generic pressure increase is useful especially in connection with a common rail system. In common rail fuel injection, primary pressure generation and injection are decoupled. The injection pressure is generated independently of the engine speed and the injection quantity and is made available in the “rail” (fuel line) for injection. A favorable course of injection can be fundamentally achieved in this manner, because the injection pressure and injection quantity, in particular, can be determined independently of each other for each operating point of the engine. However, the pressure in the common rail is still limited to approximately 1600 bar at this time; increasing the pressure is desired for reasons related to emissions and fuel consumption. A pressure booster in combination with a common rail system could therefore deliver especially good results. The problems mentioned above exist as a result of the use of the 3/2 valve, however, which has a detrimental effect overall on the performance of the injection system.
ADVANTAGES OF THE INVENTION
The injection device provided by the present invention according to claim 1 is based on the related art in that the valve device includes at least one first valve and a second valve which can be operated by the setting element via a common hydraulic coupling space. In this manner, the disadvantages are prevented, for instance, that occur with the use of a 3/2 valve made known in the related art. Since both valves can be operated by the same setting element, the equipment expenditure is not increased at this point as compared with the use of a single 3/2 valve, so that, overall, the system is improved. For instance, by suitably adjusting the elastic materials, it is possible for the valves to respond to activation by the setting element at different points in time. The hydraulic coupling space also serves to provide a power-travel transfer that may be necessary and to offset tolerances, e.g. changes in length.
Preferably, a pressure booster for boosting a primary pressure is provided, which can be operated by the valve device. High injection pressure can be achieved especially well in this manner. Since it is no longer necessary to provide a 3/2 valve, the large pressure differences that arise due to the pressure booster can be controlled while avoiding high losses due to leakage.
The setting element is preferably a piezoactuator. Piezoactuators have proven successful as electronically controllable setting elements, especially since they are compact in design and perform reliably. Moreover, the setting function can be changed by changing the parameters (voltage, pulse duration) of the control.
The primary pressure is preferably provided by a common rail. It is hereby possible to combine the advantages of a common rail system with the pressure-boosted injection device. The common rail pressure, which is currently limited to approximately 1600 bar, can be intensified; this reduces emissions and fuel consumption.
It is advantageous for the injection system to be pressure-controlled. This ensures that the injection valve actually opens only above a certain threshold pressure. This guarantees the advantages of injection using high pressure under all circumstances.
Preferably, the first valve in a first state separates the primary pressure from a low-pressure space of the pressure booster, and the first valve in a second state injects the primary pressure into the low-pressure space of the pressure booster. The first valve is thereby used as a metering valve, its opening states decisively determining the supply of the system with fuel.
It is advantageous when the second valve in a first state couples a low-pressure space of the pressure booster with a leakage system, and the second valve in a second state separates the low-pressure space of the pressure booster from the leakage system. The second valve can thereby serve as a discharge valve for the pressure valve; moreover, the pressure booster can be filled using the second valve.
It is especially advantageous when the first valve and the second valve are coordinated with each other in such a way that, by operating the setting element, the second valve can first be transferred from its first state to its second state and, as a result, the first valve can be transferred from its first state to its second state. This ensures that the opening cross-sections of the valves do not overlap. This leads to a marked reduction in the leakage rate that occurs, because the second valve is already closed when the first valve is still located in its closed first state. Additionally, it is possible to open and close the first valve numerous times (in a timed manner) while the second valve remains closed.
Preferably, a low-pressure space of the pressure booster is connected with a high-pressure space of the pressure booster via a check valve, by means of which the high-pressure space can be filled. The high-pressure space must be filled in every injection cycle so that fluid is available for high-pressure injection. A check valve prevents the high pressure from the high-pressure space of the pressure booster from reaching the low-pressure space of the pressure booster; on the ot
Douglas Lisa A.
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
Injection device and method for injection of fluids does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Injection device and method for injection of fluids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Injection device and method for injection of fluids will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3001577