Fluid sprinkling – spraying – and diffusing – Unitary injection nozzle and pump or accumulator plunger
Utility Patent
1999-08-12
2001-01-02
Kashnikow, Andres (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Unitary injection nozzle and pump or accumulator plunger
C239S124000, C239S533200, C239S585100, C123S446000, C123S467000, C251S048000, C251S051000
Utility Patent
active
06168091
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to electronically actuated oil valves, and more particularly to a noise reducing oil control valve for a hydraulically actuated fuel injector.
BACKGROUND ART
Caterpillar, Inc. of Peoria, Ill. manufactures a line of hydraulically-actuated electronically-controlled fuel injectors that have been well received and performed magnificently for many years. These fuel injection systems use high pressure lubricating oil from a common rail as a working fluid to pressurize distillate diesel fuel within each individual fuel injector for injection. Each individual injector includes an electronically actuated control valve that opens and closes the fuel injector to the common rail source of high pressure oil. Typically, this control valve includes a solenoid armature attached to a poppet valve that is moveable between a high pressure seat and a low pressure seat. To initiate each injection event, the solenoid is energized to pull the armature and poppet valve member upward from the high pressure seat toward the low pressure seat. This allows high pressure oil to flow into the fuel injector to move an intensifier piston and pressurize fuel for an injection event.
Although the control valve generally only has to move on the order of hundreds of microns between its closed and opened positions, it must move relatively fast in order to maintain performance at acceptable levels. This relatively high speed movement between positions results in the poppet valve member impacting its seats with a certain impact velocity. These impacts produce noise, which can be annoying when not drowned out by other engine noise, such as at idle conditions. In some instances, those unfamiliar with the proper operating sounds of the system can misperceive this clicking noise produced by the poppet valve hitting its seat as an indicator of some malfunction in the engine. In general, the clicking noise is barely, if at all perceptible at higher engine operating conditions because of the other engine noises, such as combustion, tend to drown out the poppet impact noise.
Because of the annoyance sometimes caused by the injector noise, particularly at idle, engineers are often seeking ways to make the system quieter. Unfortunately, it is often difficult to reduce noise at idle conditions while not undermining performance at rated conditions, or undermining the engines cold start ability. Those skilled in the art will appreciate that noise at idle can be reduced by lowering the impact velocity, and this can be accomplished by exploiting the available oil to slow the movement of the armature and poppet valve member. Unfortunately, solutions to this perceived noise problem that do not undermine the engine's cold start abilities or undermine injector performance at higher operating conditions is often elusive.
An earlier Caterpillar, Inc. U. S. patent to Ausman, et al., identifies and discusses some issues relating to damping the motion of oil control valves in hydraulically actuated fuel injectors. Ausman, et al., recognized that an amount of oil often must be displaced when the valve moves from one position to another. Although Ausman, et al., did not discuss the issue of noise at idle or at any other operating conditions, they did recognize that the valves motion could be damped by restricting the displacement of oil that occurs when the valve moves from one position to another. Ausman, et al., appears to be directed toward providing a sufficient amount of damping to prevent excessive bouncing when the valve member impacts its seat, rather than toward strategies for reducing noise produced by such an impact. In order to maintain the ability to cold start an engine, Ausman, et al., teaches a structure that ensures that virtually all damping oil in the armature cavity has the ability to drain away when the engine is shut down. In fact, Ausman, et al., specifically teaches a structure that prevents highly viscous oil from entering the armature cavity, where damping takes place, during cold start up conditions. While Ausman, et al., does touch upon some of the issues relevant to present invention, they fail to recognize any problem associated with injector noise at idle conditions, or provide any teaching that could be applied toward reducing injector noise across its operating range while preserving the engine's ability to cold start.
The present invention is directed to these and other problems associated with injector noise and cold starting ability.
DISCLOSURE OF THE INVENTION
An electronic controlled oil valve includes a valve body having an upper surface and a lower surface that partially define an armature cavity. The valve body also defines a fluid displacement passage that is separated from the upper surface and lower surface, and extends between the armature cavity and a low pressure area. A solenoid that includes an armature is positioned in the armature cavity. A valve member is attached to the armature and moveable in the valve body between a first position and a second position. The armature cavity decreases in volume when the valve member moves toward its first position. An amount of oil is maintained in the armature cavity at a level below the fluid displacement passage, but above the lower surface. The electronically controlled oil valve finds preferred application as a control valve in a hydraulically actuated fuel injector.
REFERENCES:
patent: 5125807 (1992-06-01), Kohler et al.
patent: 5236173 (1993-08-01), Wakeman
patent: 5375576 (1994-12-01), Ausman et al.
patent: 5651501 (1997-07-01), Maley et al.
patent: 5752659 (1998-05-01), Moncelle
patent: 5806766 (1998-09-01), Krueger et al.
patent: 5820033 (1998-10-01), Cooke
patent: 5904300 (1999-05-01), Augustin
Goudarz Haji
Rodier William J.
Caterpillar Inc.
Ganey Steven J.
Kashnikow Andres
McNeil Michael B.
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