Peak Injection Pressure Research Articles

Micromolding of Polymer Nanocomposites Diagnosed by Ultrasound

Miniaturized ultrasonic sensors, fabricated onto the mold insert of a micromolding (MM) machine, have been applied for real-time diagnosis of micromolding of polymer nanocomposites, nylon66 with polyhedral oligomeric silsesquioxanes (POSS) as nanofiller. The process dynamics, such as melt arrival, mold open and part detachment, were successfully monitored during molding. Ultrasound was capable of measuring peak injection pressure and material solidification process. In the pressure range between 50 and 150 MPa, the ultrasonic velocity linearly increased with a changing ratio of 2.6(m/s)/MPa. It was also found that concentration of the nanofiller (POSS) could be evaluated by using ultrasonic velocity measurement. In the concentration range of POSS between 0% and 8% the ultrasonic velocity linearly decreased with a changing ratio of 7.38(m/s)/%. The presented ultrasonic sensors and technique optimize the micromolding of nanocomposites, and improve the part quality and process efficiency by controlling mold cycle time.

Fueling an D.I. agricultural diesel engine with waste oil biodiesel: Effects over injection, combustion and engine characteristics

The paper presents the results of a research concerning the use of a biodiesel type fuel in D.I. Diesel engine; the fuel injection system and the engine were tested. The results indicated that the injection characteristics are affected when a blend containing 50% methyl ester and 50% petrodiesel is used as fuel (injection duration, pressure wave propagation time, average injection rate, peak injection pressure). As a result, the engine characteristics are also affected, the use of the biodiesel blend leading to lower output power and torque; the lower autoignition delay and pressure wave propagation time led to changes of the cylinder pressure and heat release traces and to lower peak combustion pressures.

Comparative analysis of two injection systems fueled with biodiesel

The paper presents experimental results concerning the fueling of two injection systems for D.I. Diesel engines with Biodiesel fuels. The neat Biodiesel (B100) was obtained from waste vegetable oil (collected from a local branch of McDonald’s), using the base catalyzed method; diesel fuel was also used in order to test the injection equipments and obtain reference values. The fuel injection pumps used during the tests were RO-PES4A90D410RS2240 (romanian) and a Bosch type one (PES5MW55/320/RS/120403), with the corresponding high pressure fuel lines and injectors. The injection equipment was mounted on a MIRKOZ test bed, equipped with pressure transducers, rotation angle transducer and a BOSCH injection rate meter. The tests were developed at different pump speeds and displacements of the injection pump control rack. The following injection characteristics were investigated: cyclic fuel delivery, injection duration, pressure wave propagation time, average injection rate, peak injection pressure. For the both types of injection equipment, cyclic fuel delivery, injection duration and peak injection pressure increased when biodiesel was used as fuel (compared to Diesel fuel), while the average injection rate and pressure wave propagation time decreased.

Effect of Sand Production on Casing Integrity

Abstract This paper documents a case study about the effect of sand production on casing damage. Many wells were converted from production to water injection. Formation of precipitates across the injection interval required frequent well washing which in-advertently involved reducing the well pressure rapidly. Consequently, solids were released from the formation into the wells. The well washing and associated solids production went unnoticed for an unknown length of time until significant casing deformation was encountered during a recent workover. The significant solids production caused casing buckling near the perforation interval. It also activated a weak plane in the overburden, causing further casing damage. This paper will present relevant field data and engineering analyses to support the above conclusions. Field measures to improve the casing's resistance against the buckling are also described. Introduction This paper is concerned with casing integrity in conventional onshore reservoir production in the Niuzhuang area of the Shengli Oilfield in China. Worldwide experience shows that origins of casing failure are complex. Reservoir geology, drilling and cement practices, production drawdown schemes and casing hardware can all influence casing integrity. Nevertheless, major casing damage mechanisms can be summarized as follows:chemical corrosion(1, 2);shear deformation along re-activated weak planes(3–8);significant reservoir compaction(9–11); and,excessive sand production(12–16). Chemical corrosion is a major casing damage mechanism in the NiuZhuang field. In a total of six wells being investigated, damage to five of those wells was caused by corrosion(17). However, this paper describes another casing failure mechanism; unintended excessive sand production. The following description will first present relevant field data. Mathematical analyses are then carried out to quantify the damage mechanisms. Finally, field measures are proposed to correct the problem. Reservoir Geology and Rock Mechanical Properties Production in the NiuZhuang field mainly comes from two sand bodies at a depth of approximately 3,200 m. The reservoir is struc-turally simple with only a small normal fault at an offset of 10 m. The original reservoir pressure is abnormally high at 1.68 SG. Av-erage reservoir permeability based on core analysis is 24.5 mD and porosity is 18.2%. Porosity is the major fluid conduit and storage. Natural fractures are not developed. Initial well production rate is very high, but the productivity decreases rapidly. Full production started in 1993. Water injection was needed in late 1994. The effect was seen at the production wells usually four to six months after water injection started at the surrounding wells. No rock mechanical tests were done on our target reservoir rocks. Instead, rock mechanical properties were calculated from well logs and petrophysical data using Baker Hughe's LMP (Log of Mechanical Properties)(11). Table 1 lists the average properties calculated at reservoir pressures equal to the peak injection pressure (70 MPa) or the minimum pressure reached during well washing (35 MPa). Table 1 also includes a set of lab-measured mechanical properties on a similar stratum in an adjacent oil field. Well History and Casing Damage Well N42 experienced significant casing deformation.

Influence of injection rate shaping on combustion and emissions for a medium duty diesel engine

This paper describes the effects of injection rate shaping on the combustion, fuel consumption and emission of NOX and soot of a medium duty diesel engine. The focus is on the influence of four different injection rate shapes; square type 1, square type 2, boot and ramp, with a variation of maximum injection pressure and start of injection (SOI). The experiments were carried out on a 1 liter single cylinder research diesel engine equipped with an amplifier-piston common rail injection system, allowing the adjustment of the injection pressure during the injection event and thus injection rate as desired. Two strategies to maintain the injected fuel mass constant were followed. One where rate shaping is applied at constant injection duration with different peak injection pressure and one strategy where rate shaping is applied at a constant peak injection pressure, but with variable injection duration. Injection rate shaping was found to have a large effect on the premixed and diffusion combustion, a significant influence on NOx emissions and depending on the followed strategy, moderate or no influence on soot emission. Only small effects on indicated fuel consumption were found.

Unit injectors with piezo actuator for Euro 4 diesel engines

Diesel engines will only conform to the impending European and North American emissions limits with high performance injection systems. Together with Volkswagen, Siemens VDO Automotive has therefore developed the piezo unit injector (PUI), which allows more than 2,000 bar peak injection pressure and even more precise control of the injection process and injection quantities. The unit injector diesel engines with these PUI elements have unrivalled acoustic properties and conform to the exhaust standard Euro 4.

Clinical Measurements of Cement Injection Pressure During Vertebroplasty

Clinical study of injection pressure during vertebroplasty. To investigate the range of injection pressures during conventional vertebroplasty interventions and to study the influence of syringe design and cement polymerization time on injection pressure. Vertebroplasty is an efficient procedure for the treatment of painful vertebral fractures. However, cement leakage is a potentially serious complication. Although injection pressure has been suggested as a factor for extravasation risk, to date, there are only anecdotal reports of pressure data for cement augmentation in the clinic. Using a syringe holder instrumented with load and displacement transducers, injection pressure and volume were recorded in vivo during conventional cement augmentation. Wide (3 mm opening) and normal (1.8 mm opening) syringes were alternated such that each type was evaluated for early (300-500 seconds postmixing) and late (>500 seconds postmixing) cement polymerization time. The influence of syringe type and polymerization time on injection pressure was evaluated using a multifactorial analysis of variance followed by Scheffe post hoc comparison. The maximum peak injection pressure measured was 3215 kPa. The average pressure peaks for normal and wide syringes were 1693 +/- 653 kPa and 1727 +/- 597 kPa, respectively. No statistically significant differences were found between injection pressures with wide and normal syringes. Higher injection pressures were observed later in the polymerization process. High injection pressures approaching 20 atmospheres are reached during conventional vertebroplasty. Widening the syringe tip diameter did not significantly change injection pressures, whereas elapsed time did. Further research is needed to improve injection equipment and materials for vertebroplasty.

Power Injection of Contrast Media via Peripherally Inserted Central Catheters for CT

To evaluate patient safety, catheter rupture rates, and computed tomography (CT) image quality when using peripherally inserted central catheters (PICCs) in vivo for the power injection of CT contrast media at standard injection rates. A prospective study to evaluate the safety and effectiveness of power injection of contrast media via indwelling PICCs was performed. Single-lumen and double-lumen polyurethane PICCs (5 F) were injected in vivo with contrast media for clinical CT examinations at injection rates ranging from 1 mL/sec to 4 mL/sec. Data collected included PICC rupture rate, patient complications, injection rate, peak injection pressure, PICC length, PICC age, and quality of contrast enhancement on the CT images. One hundred ten power injections of PICCs for CT examinations were performed. There were 12 injections of single-lumen PICCs and 98 injections of double-lumen PICCs. The most common injection rate was 2 mL/sec, accounting for 89 of the 110 injections (81%). Two PICCs ruptured during power injection, both as a result of operator error. One of the PICCs that ruptured was clamped at the time of injection and the other one was kinked at its venous entry site. One additional PICC showed evidence of dysfunction; it ballooned without actually rupturing. No significant patient complications occurred. Contrast enhancement of the CT images was subjectively rated as average or above average in 95% of cases. Contrast media can be power-injected via PICCs for routine CT examinations at a rate of 2 mL/sec, yielding satisfactory image quality without exposing patients to significant additional risk. Power injection rates greater than 2 mL/sec, as are typically used in CT angiography applications, were not fully evaluated by this study.

Parametric Characterization of High-Pressure Diesel Fuel Injection Systems

The focus of the study described herein is the characterization of the high-pressure hydraulic electronic unit injector (HEUI) and of the electronic unit injector (EUI) diesel injection systems. The characterization items include injection pressure, injection rate, injector response time, needle lift, start up injection transient, and dynamic discharge coefficient of the nozzles. Macroscopic and microscopic spray visualizations were also performed. The effects of injection conditions and nozzle configurations on injection characteristics were reviewed. Nozzle sac pressure was measured to correlate with the up-stream injection pressure. A LabVIEW data acquisition and controls system was implemented to operate the injection systems and to acquire and analyze data. For an HEUI system, based on the results of the study, it can be concluded that common-rail pressure and length of the injection rate-shaping pipe determine the injection pressure, while the pressure rising rate and injection duration determine the peak injection pressure; it was also found that the nozzle flow area, common-rail pressure, and the length of the rate-shaping pipe are the dominating parameters that control the injection rate, and the rate shape is affected mainly by common-rail pressure, especially the pressure rising rate and length of the rate-shaping pipe. Both injection pressure and ambient pressure affected the spray tip penetration significantly. The penetration increased corresponding to the increase of injection pressure or decrease of ambient pressure. The variation of spray penetration depends on the type of injection system, nozzle configuration, and ambient pressure. The large penetration variation observed on the HEUI sprays could be caused by eccentricity of the VCO (valve-covered-orifices) nozzle. The variation of the mini-sac nozzle was 50% less than that of the VCO nozzle. The near-field spray behavior was shown to be highly transient and strongly depended on injector design, nozzle configuration, needle lift and oscillation, and injection pressure.

(3-08) Influence of Physical and Chemical Properties of Biodiesel Fuel on Injection, Combustion and Exhaust Emission Characteristics in a DI-CI Engine((AF-3)Alternative Fuels 3-Biomass Fuels and Fuel Design)

The objectives of this study are to clarify the influence of fuel physical properties on injection characteristics by means of numerical simulation of injection system fueled biodiesel fuel, and to clarify the influence of components of the fatty acid methyl ester on the engine performance and characteristics of exhaust emissions ; PM, NOx, etc, including unregulated emissions by experiments. In these experiments, several kinds of biodiesel and methyl oleate and methyl linoleate were investigated, both of which are main chemical components in biodiesel (Table 1). The curves of bulk modulus depending on liquid pressure and temperature are different between gas oil and biodiesel. The computed simulations show that a at lower fuel temperature ; 293 and 313 K, the injection pressure of biodiesel rises earlier than that of gas oil. This is because at lower liquid pressure, the bulk modulus of biodiesel is higher than that of gas oil (Fig. 2), so that the rate of liquid pressurerise goes up and the injection timing is advanced. And peak injection pressure at biodiesel is higher than that at gas oil in the case of lower mean injection pressure. But, it becomes be similar to that at gas oil under higher mean injection pressure. At higher fuel temperatures, there are no differences in injection timing and pressure between biodiesel and gas-oil. From experimental obtained on DI-CI engine, SOF in PM by biodiesel emitted more than that by gas oil on a low engine load (Fig. 3). From the results obtained on spray visualization by the laser-sheet technique, it was found that the spray penetration by biodiesel become shorter than that by gas oil, so that the mixing of air and fuel deteriorated, and a fuel-rich mixture is formed and emitted as SOF. A SOF concentration and ignition delay increase corresponded with a decrease of the fraction of methyl oleate ester in biodiesel fuel. This will be due to low ignitability of methyl linoleate ester.

Plastic dental local anaesthetic cartridges: a laboratory investigation

The pressures applied to the bungs of glass and plastic dental local anaesthetic cartridges which were necessary to cause failure of the system were measured. Plastic cartridges did not fracture, but they failed due to leakage of solution around the bung at pressures less than those needed to break glass cartridges. At the peak injection pressures which may be obtained during intraligamentary injections, it was established that the theoretical incidence of failure was 1.4% for glass and 75.1% for plastic cartridges.

Programmed left ventricular contrast injection: A method to minimize left ventricular irritability during angiography

Left ventricular angiography frequently produces one or more premature atrial or ventricular contractions which may make quantitative volume analysis unreliable. Three hundred left ventricular power injections were analyzed and found to produce premature ventricular contractions (PVC's) in 28 per cent of injections and PAC's in 6 per cent. Forty-four per cent of injections starting near the end of the T wave were associated with PVC's, whereas those starting near the end of diastole during the P wave produced PVC's in only 11 per cent. Injections through a Gensini catheter were associated with PVC's in 24 per cent compared to 37 per cent when a pigtail catheter was used (p less than 0.05). The introduction of an 0.6 second delay in the development of peak injection pressures and ECG triggering to start the injection in the last half of the cardiac cycle did not alter the incidence of PVC's. The use of timed diastolic injections with pressure rate-rise delay is of little value in reducing injection induced arrhythmias.