Quartz Pressure Transducer Research Articles

Combustion Ionization for Detection of Misfire, Knock, and Sporadic Preignition in a Gasoline Direct Injection Engine

Detection of combustion-related phenomena such as misfire, knock, and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions. This paper applies several types of combustion ionization sensors, and a pressure transducer that directly senses the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four-cylinder gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a piezo quartz pressure transducer, MSFI (multi-sensing fuel injector), a stand-alone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles, the spark plug sensor and MSFI appear to be the most favorable, followed by the stand-alone mounted sensor which is an addition to the engine.

Measurements of Saturation Pressures for Trifluoroethene (R1123) and 3,3,3-Trifluoropropene (R1243zf)

Saturation pressures for new low global warming potential refrigerants trifluoroethene (R1123, CF2═CHF) and 3,3,3-trifluoropropene (R1243zf, CF3CH═CH2) were measured by the isochoric method for temperatures between 278 and 377 K. Temperature was measured with a 25 Ω standard platinum resistance thermometer on ITS-90. Pressure was measured with a digital quartz pressure transducer. The experimental uncertainties in temperature and pressure are estimated to be 5 mK and 1 kPa (k = 2), respectively. New saturation-pressure correlations for the refrigerants have been formulated based on the present saturation-pressure data. The critical pressures of R1123 and R1243zf were also determined.

Physical characteristics on high-pressure combustion and propelling process of bulk-loaded energetic liquid

The objective of this study is to analyze high-pressure combustion characteristics of liquid propellant and projectile motion problem of the bulk-loaded propellant gun (BLPG). The BLPG described utilizes a mixture of hydroxyl ammonium nitrate and hydrocarbon fuel to replace gunpowder typically used in such guns. The motivation for such a development is to discard the need for a shell casing whereby carrying only propellant and bullets will reduce both the mass and volume per shot. The combustion processes of the bulk-loaded energetic liquid propellant are transient and mainly controlled by turbulent mixing of gas–liquid, thus resulting in the instability of interior ballistics of the BLPG. In this work, direct measurements of the pressure variation and projectile velocity with multiple chamber geometries on the combustion process of bulk-loaded liquid propellant are performed using quartz pressure transducer and timing device. The results indicate that better ballistic repeatability is achieved with the stepped-wall structure for the combustion chamber of the BLPG and a useful degree of controlling pressure oscillation is also achieved by this stepped-wall geometry. Moreover, based on this background, the numerical simulation is devoted to a special combustion issue under transient high-pressure and high-temperature condition, namely studying steady combustion mechanism in a stepped-wall combustion chamber with full monopropellant on one end of that is stationary and the other end can move with a high speed. The numerical results present utilizing the stepped-wall geometry in the combustion chamber itself can exert boundary control on combustion evolution during part of the interior ballistic cycle and the steps can induce an increase in the radial turbulent flow components causing a faster burn time to the chamber wall that lead to a reduction in the gas–liquid surface area, which is the postulated source of instabilities that have resulted in pressure variations.

Measurements of PρT properties, vapor pressures, saturated densities, and critical parameters for R 1234ze(Z) and R 245fa

Pressure-density-temperature (PρT) properties, vapor pressures, and saturated liquid and vapor densities for refrigerants R 1234ze(Z) (cis-1,3,3,3-tetrafluoroprop-1-ene; CF3CHCHF) and R 245fa (1,1,1,3,3-pentafluoropropane; C3H3F5) were measured with two types of isochoric methods. Pressure was measured with a digital quartz pressure transducer. Temperature was measured with 25 Ω standard platinum resistance thermometer on the ITS-90 temperature scale. Density was calculated from the mass of sample and the inner volume of pressure vessel. By using the present vapor pressure data, new vapor pressure correlations for R 1234ze(Z) and R 245fa have been formulated. In addition, the critical temperature Tc, critical density ρc, and critical pressure Pc were directly determined on the basis of direct observation of the meniscus disappearance.

Characterization of Local Cavity Pressures in Squeeze Casting of Magnesium Alloy AM50

In this study, the experimental measurement of the pressure distribution in a cylindrical die cavity for squeeze casting of magnesium alloy AM50A was carried out. Piezo-electric quartz pressure transducers were integrated into a die cavity for real-time pressure measurements. The experimental results revealed that local cavity pressures at various locations changed with time in the duration of squeeze casting solidification and cooling. The pressure transfer rate varied considerably within the casting geometry. The distribution of local cavity pressures was inhomogeneous in the cavity.

Measurement of gas storage processes in shale and of the molecular diffusion coefficient in kerogen

Total gas storage capacity in many shale gas reservoirs arises from three sources: compressed gas in the micro- and nano-scale pores, adsorbed gas on the inner surfaces of pores in kerogen—the main constituent of organic materials in shale—and dissolved gas molecules in kerogen. The storage capacity of and transport processes for each of these three sources of gas are different, and accordingly, appropriate models and production strategies should be developed on the basis of actual physics. Of great relevance to field development and management is knowing the contribution of each source to daily production and ultimate gas recovery. A valuable body of literature has addressed the first two sources, but the last source has not been studied in detail. We developed a technique to measure the gas capacity from each of the above-mentioned three sources simultaneously, in a small piece of a shale sample, through batch pressure decay experiments. Temporal pressure decay is recorded using a quartz high-resolution pressure transducer for several days. The pressure-decline curve shows distinctive slope changes representing different storage processes. Pressure decline at the earliest time represents gas migration into the micro- and nano-pores. This is followed by a change in the slope of the pressure decline in an intermediate time, representing gas adsorption onto the inner surface of kerogen pores. At the later time, the slope of the pressure decline changes again, representing gas diffusion into kerogen. In the samples we tested, we found that dissolved gas in kerogen can contribute about 22% of the total gas-in-place. Assuming that gas molecules diffuse into the walls of the pores in kerogen, we used a Fickian diffusion model and a parameter-estimation technique to estimate the gas molecular diffusion coefficient in kerogen. We measured the diffusion coefficient of methane in amorphous kerogen as being on the order of 10−20m2/s.

Dynamic neural network calibration of quartz transducers

AbstractThe performance of quartz pressure transducers is often compromised when subjected to thermal transients. In this paper, a new method of calibrating quartz transducers in which a neural network is used to accomplish a dynamic calibration of a transducer pair for a range of temperatures and pressures will be described. When a quartz pressure transducer is exposed to an environmental temperature change, thermal stress is induced in the sensing element. This thermal stress causes erroneous pressure readings until thermal equilibrium is achieved within the transducer. In order to compensate the undesirable transient thermal effects on the pressure transducer performance, multiple past and future temperature‐and‐pressure sensor outputs are used as inputs to a calibrating neural network. This new method allows the time‐dependent qualities of the quartz‐oscillator transducer to be included in the calibration scheme. This method can be applied generally to other types of transducers that are subjected to transient environmental effects and is not limited to quartz‐oscillator transducers. A theoretical discussion of this technology is presented, followed by experimental results obtained by applying the method to quartz pressure transducer calibration. Copyright © 2002 John Wiley & Sons, Ltd.

Accurate Volume Measurement System for Plutonium Nitrate Solution

Abstract An accurate volume measurement system for a large amount of plutonium nitrate solution stored in a reprocessing or a conversion plant has been developed at the Plutonium Conversion Development Facility (PCDF) in the Power Reactor and Nuclear Fuel Development Corp. (PNC) Tokai Works. A pair of differential digital quartz pressure transducers is utilized in the volume measurement system. To obtain high accuracy, it is important that the non-linearity of the transducer is minimized within the measurement range, the zero point is stabilized, and the damping property of the pneumatic line is designed to minimize pressure oscillation. The accuracy of the pressure measurement can always be within 2 Pa with re-calibration once a year. In the PCDF, the overall uncertainty of the volume measurement has been evaluated to be within 0.2%. This system has been successfully applied to the Japanese government's and IAEA's routine inspection since 1984.

Evaluation of intraocular pressure fluctuations with differing phacoemulsification approaches

Simultaneous two-camera video tracings of phacoemulsification surgery and intraocular pressure fluctuations were made. The fluctuations were transmitted to a quartz pressure transducer through a chamber maintainer that was plugged into the anterior chamber. The transducer was connected to a monitor and recorder calibrated to measure pressure variations between -8.6 and +60 mm Hg. Using common audio for synchronization, the pressure tracings were keyed over the surgical videos and combined in a single film. High, medium, and low inflow volume techniques used by many surgeons exhibiting commensurately higher or lower intraocular pressure fluctuations were scrutinized. Methods to increase inflow volume without a proportionate pressure increase were devised.

Accurate Volume Measurement System for Plutonium Nitrate Solution.

Abstract An accurate volume measurement system for a large amount of plutonium nitrate solution stored in a reprocessing or a conversion plant has been developed at the Plutonium Conversion Development Facility (PCDF) in the Power Reactor and Nuclear Fuel Development Corp. (PNC) Tokai Works. A pair of differential digital quartz pressure transducers is utilized in the volume measurement system. To obtain high accuracy, it is important that the non-linearity of the transducer is minimized within the measurement range, the zero point is stabilized, and the damping property of the pneumatic line is designed to minimize pressure oscillation. The accuracy of the pressure measurement can always be within 2 Pa with re-calibration once a year. In the PCDF, the overall uncertainty of the volume measurement has been evaluated to be within 0.2%. This system has been successfully applied to the Japanese government's and IAEA's routine inspection since 1984.

STRATIFIED VAPOR EXPLOSION EXPERIMENTS

Abstract An experimental investigation has been conducted on vapor explosions in a stratified contact mode, where the cold liquid and the hot liquid are initially separated by a stable vapor film. A series of experiments were conducted in a narrow, rectangular vessel (20 cm long, 2.54 cm wide, 65 cm high). One face of the vessel wall is made of transparent material for the visual observation using a high speed camera. The explosion is externally triggered at the one end of the vapor film layer by a pressure shock produced by a magnetic hammer. Four quartz pressure transducers are mounted horizontally at the vessel wall. The mechanical energy release is measured by the displacement of a slug which is initially held at the middle of the vessel. The results with water (10 ∼ 85°C) and saturated liquid nitrogen (− 196°C) show that the explosion propagates along the vapor film interface at a speed of 100∼250m/s. The mechanical energy release was up to 33 joules. The variation of the triggering shock pressure re...

Lake level observations to detect crustal tilt: San Andreas Lake, California, 1979–1989

A pair of precision lake level gauging stations, installed in 1978, have been monitoring differential crustal uplift (crustal tilt) at San Andreas lake, California, near the suspected epicenter on the San Andreas fault of the M=8.3, 1906 San Francisco earthquake. The stations are installed in the lake with a 4.2 km station separation parallel to the San Andreas fault. The gauging stations use quartz pressure transducers that are capable of detecting intermediate to long‐term vertical displacements greater than 0.4 mm relative to a fluid surface. Differencing data from the two sites reduces the noise contributed by atmospheric pressure, temperature, and density changes, and isolates the relative elevation changes between the ends of the lake. At periods less than 20 minutes, the differenced data are dominated by lake seiches which have a fundamental mode at a period of 13±0.3 minutes. These seiche harmonics can be filtered or predicted and removed from the data. Wind shear, typically lasting several days, can generate apparent short term tilt of the lake and large seiche amplitudes. The tilt noise power spectrum obtained from these data decreases by about 15 dB/decade of frequency. Monthly averages of the data between 1979–1989 indicate a tilt rate of 0.02±0.08 microradians/yr (down S34°E). No measurable horizontal tilt has apparently occurred in this region of the San Andreas fault during the last decade, however, measurements of trilateration networks show this region to be undergoing a horizontal strain of 0.6±0.2 µstrain/yr.

Advanced Design Concepts for Fused Quartz Pressure Transducers

The author presents the engineering design considerations applied in the development of a laboratory grade pressure standard utilising a fused quartz Bourdon tube transducer, and its adaptation to uses in field service and process control industries.

Digital heart rate monitor derived from the arterial pressure pulse

This monitor displays heart rate without the need for electrical contact with the experimental animal. The device uses a quartz pressure transducer connected to an arterial catheter and has a full scale accuracy of ± 3 beats min −1; its range is 0–400 beats min −1. There is an output voltage proportional to heart rate and internal calibration facilities are provided at 60 and 360 beats min −1.

Vertical geodesy without slope dependent errors—a proposed hydrostatic pressure level using water at 4°C

ABSTRACT Bilham, R., 1983. Vertical geodesy without slope dependent errors—a proposed hydrostatic pressure level using water at 4°C. In: P. Vyskocil, M.A. Wassef and R. Green (Editors), Recent Crustal Movements, 1982. Tectonophysics, 97: 337–349. Conventional vertical geodesy using spirit levelling has two fundamental shortcomings: it is expensive to perform and it is associated with systematic errors that are temperature and slope-dependent. A hydrostatic level is described that, in theory, can more than double the speed of 1st-order levelling and provide a measurement precision of better than 1 cm per vertical kilometer of traverse. In the favoured design digital quartz pressure transducers are used to measure the pressure at each end of a 100–200 m long flexible tube containing water at its maximum density. The entire instrument is maintained at 4 ± 1°C by truck-mounted machinery at the leading end of the hydrostatic level. The digitally recorded measurements are expected to provide a single set-up resolution better than 0.1 mm over a vertical range of 4–10 m, a random error of 0.3 mm/√km of horizontal traverse and a vertical precision of the order of one part in 105 independent of weather conditions.

Semiconductor Thin Film Transducers of Rapidly Varying Pressures

Results are presented of studies on the application of Ge, InSb, Cd3As2, PbxSn1-x Te, MnxHg1-x Te thin films as transducers of rapidly varying pressure up to 0,1 GPa in non-conducting liquid media. The transmissions of rapidly varying pressures by the films studied and of a quartz pressure transducer are compared. The dynamic error involved in the pressure measuring set-up including the film tested has been determined as 1.5%.

Parallel hydrogen injection into constant-area, high-enthalpy, supersonic airflow

Although the mixing and burning of hydrogen injected into the combustion chamber are essential to the operation of a scramjet, experimental investigations of this process have been limited to speeds of less than 2.2 km/sec. The present experiment is an attempt to extend this limit to flight speeds of about 5 km/sec, whose corresponding stagnation enthalpies range up to MJ/kg. Mach-Zehnder interferograms were taken with a light source of 583 nm and 5 sec duration, while surface pressures were obtained with PCB quartz pressure transducers.

High temperature electronics for geothermal energy

Instrumentation for geothermal borehole measurements is being expanded beyond today's limited capabilities. Prototype logging tools have been successfully field-tested to 275°C; a high-resolution quartz pressure transducer and a gallium phosphide diode have been successfully tested. Near-term goals of current programs are to develop instrumentation for use at 275° in pressures up to 48.3 MPa (7000 psi).

Flow oscillations in a duct with a rectangular cross-section

A two-dimensional configuration has been investigated in which air flows through a convergent nozzle and expands abruptly into a rectangular duct of larger cross-section which terminates in a plenum chamber. Three different types of oscillation have been observed in the downstream duct. At low plenumchamber pressures an oscillation occurs towards the exit of the duct as the boundary layer of the flow becomes alternately separated and attached. At increasing plenum pressure a shock-pattern oscillation takes place in which a change from a normal shock to oblique shocks occurs during a cycle. At still greater plenum pressures a base-pressure oscillation occurs which influences the entire duct flow downstream of the abrupt change in cross-section. The amplitudes of the oscillation can be as high as 10% of the rest state, and the frequency of the base-pressure oscillations can be predicted approximately from one-dimensional gasdynamic theory.The unsteady duct phenomena have been studied by synchronizing instantaneous pressures measured by quartz pressure transducers with interferograms obtained with a Mach–Zehnder interferometer.

Properties of indium antimonide thin films as fast-response pressure transducers

Results are presented of studies on the application of InSb thin films for measuring rapidly varying pressures up to 600 atm in liquid non-conducting media. A comparison is made between this transducer and the quartz pressure transducer used as devices for measuring rapidly varying pressures. The dynamic error in a pressure-measuring system which included an indium antimonide thin film resistance transducer has been determined as less than 1.5%.