Solenoid

About: Solenoid is a research topic. Over the lifetime, 19278 publications have been published within this topic receiving 114721 citations.

System and methods for electronic control of an accumulator fuel system

Abstract: An electronic digital control system monitors and controls the operation of an engine fueling system. Signals activating injection for a plurality of cylinders are transmitted through a single line to a driving circuit for a single injector solenoid valve, while signals controlling accumulator fuel pumps are transmitted to pumping control solenoids. Injection signals are controlled to vary fuel delivery rate during an injection event. A back EMF sensing circuit measures valve opening delay and the control system compensates for valve delay. Variable cylinder-specific delays in the injection solenoid output signal pulses are programmed to compensate for a varying fuel line length to each injector nozzle. At startup, the control system pulses the pumping control solenoids to begin pressurizing the accumulator before engine angular position sensors provide an accurate indication of engine angular position to allow precise timed control of the pump. Pressure variations in the high pressure accumulator are monitored by the control system in conjunction with injection events, and pump equipment failures or weaknesses are detected based on the pressure variations. In alternative embodiments of the invention, a pre-biasing current using battery voltage is provided to the injection control valve prior to the desired time of an injection event, and the current is increased at the desired time of opening. An input allows signaling the control system when a load is to be applied to cause an immediate change in fueling levels, to prepare for load increases in electrical generation and other non-motive-power applications.

Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices

Abstract: This paper describes a method for prefabricating screw, pneumatic, and solenoid valves and embedding them in microfluidic devices. This method of prefabrication and embedding is simple, requires no advanced fabrication, and is compatible with soft lithography. Because prefabrication allows many identical valves to be made at one time, the performance across different valves made in the same manner is reproducible. In addition, the performance of a single valve is reproducible over many cycles of opening and closing: an embedded solenoid valve opened and closed a microfluidic channel more than 100,000 times with no apparent deterioration in its function. It was possible to combine all three types of prefabricated valves in a single microfluidic device to control chemical gradients in a microfluidic channel temporally and spatially.

Fluid loss, damage prevention and control system

Abstract: A control system apparatus for a fluid distribution system includes a low-voltage circuit and a positive displacement disc in a throughput line such that as fluid displaces the positive displacement disc a magnet associated therewith is also rotated. The rotating magnet sets up a magnetic flux that is sensed by a switch in close proximity to the rotating magnet and when the switch closes a low-voltage current is allowed to pass to a time delay relay, which in turn monitors the duration and strength of the low-voltage current and can, under program control, further actuate another branch of the low-voltage circuit, which causes a normally open valve to be closed by a solenoid. As the solenoid is actuated, the water flowing in the throughput line is shut off.

Surface micromachined solenoid inductors for high frequency applications

Abstract: As operation frequencies and performance requirements of wireless devices increase, the resultant demands on the performance of passive components also increase. Miniaturization of inductive components for high frequency has been a key research area to address this issue; however, in general, miniaturized integrated inductors can suffer from low Q factors and/or self-resonant frequencies when compared to their discrete counterparts. In this research, a modified geometry of a solenoid type inductor using a surface micromachining technique is proposed. This inductor has an air core and an electroplated copper coil to reduce the series resistance, and its low temperature process is suitable for various packaging applications. An important feature of the proposed inductor geometry is the introduction of an air gap between the substrate and the conductor coil in order to reduce the effects of the substrate dielectric constant. This air gap can be realized using a polyimide sacrificial layer and a surface micromachining technique. Therefore, the resulting inductor can have less substrate-dependent magnetic properties, less stray capacitance, and higher Q-factor. The measurement result shows that this inductor has high Q-factor and stable inductance over a wide range of operating frequency. Also, various effects of geometrical factors have been investigated. Various inductors with the inductance varying from 1 to 20 nH and maximum Q-factor from 7 to 60 have been fabricated and measured.