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SAE TECHNICAL PAPER SERIES
2000-01-1256
Dynamics of Multiple-Injection Fuel Sprays
in a Small-bore HSDI Diesel Engine
Joong-Sub Han, T. C. Wang, X. B Xie,Ming-Chia Lai and Naeim A. Henein
Wayne State University
David L. Harrington and John Pinson
General Motor Research & Development Center
Paul Miles
Sandia National Laboratories
Reprinted From: Advances in Diesel Fuel Injection and Sprays
(SP–1498)
SAE 2000 World Congress
Detroit, Michigan March 6-9, 2000
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2000-01-1256 Dynamics of Multiple-Injection Fuel Sprays in a Small-bore
HSDI Diesel Engine Joong-Sub Han, T. C. Wang, X. B Xie, Ming-Chia Lai and Naeim A. Henein
Wayne State University
David L. Harrington and John Pinson
General Motor Research & Development Center
Paul Miles
Sandia National Laboratories Copyright ? 2000 Society of Automotive Engineers, Inc.
ABSTRACT
An experimental study was conducted to characterize the dynamics and spray behavior of a wide range of minisac and Valve-Covered-Orifice (VCO) nozzles using a high-pressure diesel common-rail system. The measurements show that the resultant injection-rate is strongly dependent on common-rail pressure, nozzle hole diameter, and nozzle type. For split injection the dwell between injections strongly affects the second injection in regards to the needle lift profile and the injected fuel amount. The minisac nozzle can be used to achieve shorter pilot injections at lower common-rail pressures than the VCO nozzle.
Penetration photographs of spray development in a high pressure, optical spray chamber were obtained and analyzed for each test condition. Spray symmetry and spray structure were found to depend significantly on the nozzle type. The minisac class of diesel nozzle definitely exhibits superior characteristics regarding hole-to-hole spray symmetry, whereas the VCO class of diesel nozzles produce a more asymmetric, but more dispersed spray plume, with potentially better fuel-air mixing performance than the minisac nozzle. The dual-guided VCO class of nozzle does not significantly improve the spray symmetry over that of the single-guided nozzle. However measurement of spray tip penetration length shows that the dual-guided VCO nozzle provides higher spray-tip velocities than is achieved for single-guided tips. The results obtained show that the liquid spray tip penetration mainly depends on nozzle type, needle guiding strategy, injection pressure, and ambient gas pressure.
Close to nozzle exit spray dynamics observation was carried out. The microscopic visualization results provide very interesting and dynamic information on spray structure, showing spray angle variations, injection-to-injection variation, and primary breakup processes not observed using conventional macroscopic visualization techniques. The near-field spray behavior is shown to be highly transient, strongly depend on the injector design, nozzle geometry, needle lift and vibration, and injection pressure which is a function of the injection system.
INTRODUCTION
Because of the associated high thermal efficiency and reduced CO2 emissions, the small-bore, high-speed, direct-injection (HSDI) diesel engine is achieving an extended application in worldwide passenger car markets. It is also a major candidate for the power plant of the partnership-for-new-generation vehicle (PNGV). Increasing the injection pressure and optimizing the injection-rate profile have been focused technologies in the development-advanced diesel engines. For small bore diesel engines the combination of high rail pressure and an injection nozzle tip having small holes and low sac volume is critical to achieving successful fuel-air mixing in the HSDI combustion chamber. The high-pressure common-rail (HPCR) injection system, with its independent pressure control and electronic injection-rate shaping capabilities, is an important enabling technology for the HSDI engine. Although diesel fuel sprays have been studied extensively over many decades, the combined effect of nozzle geometry, needle design and multiple injection events on the spray dynamics of HPCR systems is largely unknown. The objectives of this study are to characterize the dynamics and spray behavior of the high-pressure diesel common-rail (HPCR) systems, and to compare the spray characteristics of minisac, single-guided VCO and dual-guided VCO nozzles. The experimental data includes needle lift, injection pressure, injection-rate, spray plume images and liquid spray tip penetration.
Farrell et al. [4] investigated the injection dynamics and spray characteristics using a common-rail injection system having a three-way valve. It was found that pilot injection and the dwell spacing between two subsequent injections influences the spray tip penetration and cone angle of the secondary injection. The study also showed the effects of injection pressure and ambient pressure on the spray resulting from multiple injections. However a detailed parametric study is required to provide definitive guidelines for HSDI engine designer
The VCO spray structure and its asymmetry were investigated by Lai et al. [9] using a long-working-distance microscope and laser sheet illumination. It was shown that the near-field spray behavior strongly depends on the nozzle geometry, needle lift and vibration, and the injection pressure.
EXPERIMENTAL SETUP
1) Injection-Rate Measurement
Experimental apparatus consists of high-pressure electronically-controlled common-rail (HPCR) fuel injection systems, an injection-rate meter (IAV model –Bosch type [1]) and an electronic weight balance to analyze the injection-rates and total injection quantity. Figure 1 shows the schematic of the test facility. The common-rail injection system utilized was capable of providing an injection pressure of up to 1350 bar; however, a maximum of 1200 bar was used for injection-rate measurement to ensure rail pressure stability. An
investigated using an optical spray chamber pressurized by nitrogen. For the spray visualization, a short-duration stroboscope and copper-vapor laser system (Oxford CU15) served as the light source. The spray images were photographed using a 35mm still camera and a high-speed drum camera, and a waveform analyzer was used to capture the needle lift signal. The injection pressure, injection duration and ambient pressure are varied in the experiment. Because orifice and nozzle geometry significantly affects the spray, a significant range of designs and nozzle geometries were tested. T able 1
Nozzles
T able 1.Summary of Nozzle Geometry and T est
Conditions
under 100 bar injection pressure.
3) Close to Nozzle Exit Spray Dynamics Observation The optical system setup includes a long-distance microscope, a copper-vapor laser (Oxford CU15), and a high-speed drum camera. The copper laser is expanded into a thin sheet with thickness less than 0.09mm using cylindrical lens. It is used as the optical shutter, operating at 25-kHz with exposure time as short as 10 ns. The drum camera is operating at 250 revolution-per-second with 0.16 -second shutter speed. The long-distance microscope is used to magnify the diesel spray structure very close to the nozzle exit. With its lens 8.75 inches away from the observed object, the amplification factor is about 17.4. The diffraction-limit resolution can be as small as 1-2 micron.
RESULTS AND DISCUSSIONS
1. Injection-Rate Measurement
The injection-rate is defined as the instantaneous rate of fuel mass exiting from the nozzle tip. In order to control the COV of IMEP, the injection-rate, injection pressure and injection duration must be repeatable. Figure 3 shows the measured 50-injection variability at a common-rail pressure of 1200 bar, with a 54.88mg average injected quantity. The injection variation for a typical HPCR system was found to be +/-2 %(Maximum injected fuel amount was 55.99 mg and minimum injected fuel amount was 53.92mg).
Figure 3.50 Shot Cycle Variability of the Injector
(a) Effect of Back Pressure on the Injection-rate Measurement
The chamber pressure of the injection-rate meter before the start of injection is defined as the backpressure. The effect of backpressure and cavitation on the injection-rate measurement accuracy must be determined before measurements are conducted. The injection-rate was first measured by changing the backpressure in the range from 11 bar (162psi) to 37.5bar (550psi) with injection pressures ranging from 300 bar to 1200 bar. T ests with an injection duration of 2.0 ms (without a pilot injection) and 1.2/1.0/2.0 ms (with a pilot injection) indicate that the injection-rate displays the same wave form for a range of back pressures from 27 bar to 37.5 bar. At a lower range of backpressure a fluctuating waveform due to cavitation can be observed immediately after the start of injection. In order to achieve precision injection-rate measurements, the backpressure for this study was maintained at 27 bar.
(b) Effect of Common-rail Pressure & Nozzle Hole Diameter
The injection-rate is a strong function of the common-rail pressure. The injected fuel quantity is found to be nearly proportional to the square root of the sac pressure, which closely tracks the injection pressure, and the effective opening area. The rise in injection-rate for a higher common-rail pressure is clearly shown in Figure 4. The data were obtained for a 6-hole (0.18mm diameter)-dual guided VCO nozzle. The injection pressure was varied from 300 bar to 1200bar. For 1200 bar, the initial rise rate is the highest, and the start of injection is also earlier than for the lower common-rail pressure cases.
Figure https://www.doczj.com/doc/0c18002332.html,parison of Initial Injection-rates
Figure 5.Effect of Nozzle Hole Size on Measured
Injection-rate
The effect of the nozzle hole diameter on the injection-rate also was investigated. Figure 5 shows the injection-rate for a dual-guided VCO nozzle for hole diameters from 0.162 to 0.18mm. Under a constant 800-bar injection pressure, the injection-rate was found to increase as shown with increasing hole size.
(c) Maximum Needle Valve Lift
Due to working principle of the common-rail system, the needle lift time of common-rail injector is much longer
and is strongly affected by the injection pressure. For
three different common-rail pressures, the maximum needle lift was found to be different for each case. The location of the hall effect needle lift sensor may perhaps explain why the indicated maximum lift is different.Because the location of the lift sensor is at the top of the injector, which is quite far from the needle seat, there is a significant extension of the long needle before any actual opening of the nozzle.
The relationship of the needle lift and injection command signal without pilot injection is illustrated in Figure 6. As the common-rail pressure is increased, the delay time from injection command to maximum needle lift becomes shorter. For maximum needle lift, the measured delay time is 2.3ms, 1.88 ms, 1.77 ms respectively for 300-bar,800-bar, 1200-bar injection pressure.
These results explain why a rapid increase in the initial injection rate is possible with a higher common-rail pressure. The anomalous hump observed in lift-time curves during the opening periods is mostly likely a result of needle compression and the distant location of the needle lift sensor. The actual time for the spray to exit the nozzle as determined by spray visualizations corresponds very closely with the injection-rate measurement
The relationship between the common-rail pressure and the needle lift under pilot injection condition is shown in Figure 7. The injection duration was 1.2 / 1.2 /2.0 ms with the same 0.18mm hole diameter VCO nozzle. The dynamic characteristics of the needle-closing event are similar for all of the tested pressures; however, for the lowest rail pressure (300bar) a slightly faster needle valve closing was detected.
Figure 8, Figure 9 and Figure 10 show the injection rate and needle lift for the No 2-prototype injector with various injection duration’s and pressures. Due to the design and working principle, the injector is operating in partial needle lift condition regularly, especially for injection with short duration and low pressure. This result was well matched with spray penetration result, which will be shown at Figure 25.
Figure 6.Maximum Needle Lift without Pilot Injection
Figure 7.
Maximum Needle Lift with Pilot Injection
Figure 8.
Effect of Common-rail Pressure on Needle Lift of the Common-rail System, with 0.33-mm Maximum Needle Lift, and 390 FN VCO Nozzle (6 holes, 0.162-mm hole diameter, single-guide, and 6.173 L/D ratio)
Figure 9.
Injection-rate and Needle Lift of the Common-rail System under Conditions of Different Injection Duration with Common-rail Pressure of 1100 bar and 390 FN VCO
nozzle
Figure 10.Injection-rate and Needle Lift of Common-rail System under Conditions of Different injection
Duration, with Common-rail Pressure of 800
bar and 390 FN VCO Nozzle
(d) Injection-Rate Comparison for Minisac and VCO Nozzles
Figure 11 through 14 show the needle lift and injection-rate data for two types of nozzles; a 390-FN VCO nozzle and a 390-FN minisac nozzle, having 0.162mm (L/ D=6.173) and 0.147mm hole-diameter (L/D=4.082), respectively. The discharge coefficients (Cd) were 0.48 and 0.58 for the VCO nozzle and the minisac nozzle respectively. These values were computed from the flow number definition. The energy losses due to the flow turning angle at the orifice inlet could explain why the VCO nozzle has the lower discharge coefficient. Figures 11 and 12 show the injection-rate comparison with 1.2/ 1.2/1.5 ms pilot injection timing at a lower rail pressure of 300bar. The VCO nozzle was found to exhibit a shows smaller pilot injection in terms of needle lift and injection-rate.
Figure 11.Minisac and VCO Nozzle Comparison-
Needle Lift Figure 12.Minisac and VCO Nozzle Comparison –
Injection-rate
In general, the minisac nozzle can be used at a lower rail pressure and shorter pilot injection duration than the VCO nozzle. Due to higher discharge coefficients, the minisac nozzle tip delivers more fuel quantity at the shorter pilot injection duration. Examples of this are shown in Figures 13 and 14. Even though both needle lifts are identical, the injected fuel amount is different for a pilot injection in Figure 14, in which the injection pressure was 800 bar and the commanded injection duration sequence was 1.2/1.2/2.0ms
Figure 15 plots the instantaneous discharge coefficient history. The discharge coefficient is computed from the upstream pressure measured at the injector inlet, and the injection-rate measurements. While static discharge coefficients were 0.58 and 0.48 for the minisac and VCO nozzles respectively, Figure 15 shows that the maximum discharge coefficient of the minisac is nearly 0.7 while the VCO nozzle is nearly 0.6. This is consistent with the fact that the flow resistance is considerably larger for the VCO nozzle (Qin et al. [8]).
Figure 13.Minisac and VCO Nozzle Comparison Fully Opened Needle Case –Needle Lift
Figure 14.Minisac and VCO Nozzle Comparison Fully Opened Needle Case –Injection-rate
Figure 15.Discharge Coefficient Comparison - Minisac & VCO nozzle
(e) Pilot Injection
Due to the interaction of injection line hydraulics and the injector dynamics, the pilot injection and dwell duration between injections could significantly affect the needle lift and delivered fuel quantity of the secondary injection. Figure 16 shows a pilot separation sweep of needle lift for a 300-bar common-rail pressure. For this sweep the injection duration for the main injection is maintained at 0.8 ms and the pilot injection duration is maintained at
0.7 ms, but the dwell period was changed from 0.2ms to
1.0ms. The same pilot injection duration produces an unchanging pilot needle lift. However, the needle lift for the main injection changes as the dwell period is increased. Until 0.8ms dwell period, the needle lift amount decreases as the dwell decreases. But for a dwell period of less than 0.8ms, the needle lift amount increased again. The variation of the total injection-rate amount is shown in Figure 18 to be as large as 100 percentage over the separation sweep. The integrated injection-rate from injection-rate trace is very close to the mass measured using the electronic weight balance. The corresponding injection-rate is shown in Figure 17. Figure 16.Pilot Separation Sweep – Needle Lift (300
bar)
Figure 17.Pilot Separation Sweep – Injection-rate at 300 bar for 430 FN minisac
Figure 18.Injected fuel Amount Variation (300 & 800
bar, 430 FN minisac)
The measured characteristics of the needle lift with a change in dwell period were the same for No2-prototype injector. Figure 19 shows the result of a pilot separation sweep of needle lift for No2-prototype injector. This unit exhibits a slightly improved consistency, but still shows variations
A pilot separation sweep with a fully open needle condition for the main injection is shown in Figures 20 and 21. The pilot injection duration is 1.2 ms and the main injection duration is 2.0 ms for an injection pressure of 800 bar. A minisac and a VCO nozzle, both with 430 flow-numbers are used. As illustrated in Figure 22, the minisac and VCO nozzles show the same tendency regarding variations in the injected fuel quantity.
Figure 19.Injector Separation Sweep Plot – Needle Lift of No 2- Prototype Injector at 400 bar
Common-rail Pressure
(minisac)Figure 22.Injected fuel Amount Variation - Minisac &
VCO nozzle
2. Spray Penetration Visualization
In the study of spray penetration visualization, the spray visualization was carried out by injecting fuel into a room-temperature nitrogen-filled pressurized chamber .The chamber pressure was adjusted to simulate the air density at the end of compression stroke of Compression Ignition engine. In a real engine operating condition, fuel is injected to combustion chamber at the timing closed to end of a compression stroke. Hence, it is reasonable to assume that the fuel sprays issued into the pressurized chamber encounters similar drag force as it did in a real engine. Since the chamber is filled up with room temperature nitrogen gas, the fuel sprays will mostly be in the form of liquid droplets and can be treated as non-evaporative sprays.
The characterization items carried out in this study include penetration, overall structure, and hole-to-hole variation. This method could be used to measure the performance of nozzle tip, injection unit, or injection system in terms of their capability of distributing fuel as far as temporal and spatial concerns. Although under same ambient density condition both the penetration and dispersion of a evaporative spray could be much less than those of a non-evaporative one, the characteristics obtained from a non-evaporative test condition still provides good indication of the performance of a fuel injection.
(a) Spray Symmetry
The symmetry of the fuel spray was found to vary significantly with the nozzle type. The spray development for a minisac nozzle and a VCO nozzle are illustrated in Figure 24 and Figure 31. The VCO spray penetration exhibits a very asymmetric spray plume. These spray asymmetric images for the VCO nozzle tip validates the needle lift eccentricity. Furthermore, the dual-guided VCO nozzles were also not free from needle lift eccentricity (Figure 33). These data are obtained for an identical injection pressure of 800 bar and ambient
pressure of 13.5 bar.
(b) Spray Structure
The VCO nozzle shows significant puffy spray structure, larger spray angle, better spray spread and potentially better fuel-air mixing. Lai et al. [9] reported the spray angle oscillation of VCO nozzle, which results in a puffy spray structure. It was shown that the near -field spray behavior strongly depends on the nozzle geometry, needle lift and vibration. The minisac nozzle shows a thinner spray angle and a better symmetric spray penetration. This tendency is affected by the hole’s inlet curvature from the seat region to the hole region. Figure 32 shows the comparison between minisac and VCO nozzle liquid spray tip penetration.
(c) Hole-to-Hole Spray Variation and Spray Structure Significant hole-to-hole variation in penetration of the sprays of the VCO nozzle was observed, especially at the early stage of spray development, as shown in Figure 23. For this test No 2-prototype injector was used. As shown in Figure 26, with 300 bar injection pressure, the 2- and 5-o’clock sprays do not appear for the whole injection period. Based on the results obtained from the needle lift measurements, as shown in Figure 8, with 300 bar injection pressure, the needle just barely opens with little needle lift and injection rate; under this circumstance four holes are open, however the other two holes, 2- and 5-o’clock holes, remain covered by the needle. This is an evidence of needle eccentricity. As injection pressure increases to 800 bar, the injection rate and needle lift increase accordingly. The 5-o’clock hole starts to issue injection after a 0.16-ms lag time. The fastest spray is locating on the opposite side of the slowest spray. Therefore, it would be reasonable to conclude that the needle-to-seat eccentricity is most severe upon the 5 o’clock nozzle hole, which consequently reduces the flow area of the corresponding hole at the early stage of spray development. Puffy structure is observed on the 2-, 6-, 8-and 12-o’clock sprays. The puffy structure at the early development of these sprays may be categorized as hollow cone spray with characteristics of wide angle as the type of that spray Soteriou et al.[15] identified in their study . As shown in Figure 26, these early-developed sprays with puffy structure are surpassed and penetrated by the later coming solid cone sprays after 0.24 to 0.32 ms from start of injection.Figure 23.Hole-to-Hole Penetration Variation of the
Common-rail Sprays, with Single-guide 390
FN VCO Nozzle, Common-rail Pressure of
800 bar, Duration of 0.3 ms, and Ambient
Pressure of 17.2 bar.
(d) Spray Penetration
Figure 25 shows spray tip penetration employing a pilot injection. The pilot injected spray stays at a certain length and does not penetrate any more to the axial direction but starts to evaporate to the radial direction. Following main injection takes over the pilot injection.
In this split injection mode, the main (second) injection penetrates more rapidly than the pilot (first) injection, and quickly overtakes the earlier pilot spray and passes through it. This can be explained by the lower amount of needle valve opening for the pilot injection. This gives an increased pressure loss across the seat opening. Therefore the pilot penetration data shows slower penetration (Figure 27)
Figure 26. Sequences of Development of the Common-rail Sprays with Single-guide 390 FN VCO Nozzle, Duration of
0.3 ms, Ambient Pressure of 27.6 bar; Interval of 0.08-ms between Each Frame; Upper rows for Common-rail
Pressure of 300 bar; Center rows for Common-rail Pressure of 800 bar; Bottom rows for Common-rail Pressure
of 1350 bar;
Model
Figure 28, Figure 29, and Figure 30 summarize the correlation between the measured and calculated penetration under various injection and ambient pressures. The calculated penetration is based on empirical model proposed by Hiroyasu et al.[13]. Input data for the calculation include nozzle specifications,injection quantity, injection rate, density of ambient gas,and density of fuel. Value of 0.8 is used as the Coefficient of Spray Contraction for the calculation of average injection velocity, which is carried over from the study of Kuo [14]. T o best fit with the measured data, 0.8has been chosen as the values of Coefficient of Effective Injection Velocity for the calculation of penetration. In general, the model correlate fairly well with the measured data. However, the model tends to over predict the early phase of the penetration and under predict that of the later phase. The calculated penetration of CR sprays with injection pressure of 300 bar is far less than the measured data, which may indicate that the model does not apply to injection with low needle lift and low injection rate.
Figure 28.Correlation between the Measured and
Modeled Penetration of the Common-rail System, with Pressure of 1350 bar, Duration 0f 0.35 ms, 390 FN VCO Nozzle, and Ambient Pressures of 17.2 and 27.6 bar.
Orifice geometric parameters such as needle angle, L/D,curvature edge sharpness, and discharge coefficient significantly affect the rate of spray tip penetration. T o investigate a needle type effect and a discharge coefficient effect, minisac and single-guided, dual-guided VCO nozzles are investigated by differentiating the injection pressure and the chamber pressure.
Figure 29.Correlation of Measured and Modeled
Penetration of the Common-rail System, with Pressure of 800 bar, Duration of 0.35 ms, 390 FN VCO Nozzle, and Ambient Pressures of 17.2 and 27.6 bar.
Figure 30.Correlation of Measured and Modeled
Penetration of the Common-rail System, with Pressure of 300 bar, Duration of 0.35 ms, 390 FN VCO Nozzle, and Ambient Pressures of
17.2 and 27.6 bar.(f) Penetration Comparison of Minisac & VCO
The minisac nozzle design is found to provide a fairly uniform spray penetration among the various holes, but the VCO nozzle generally provides asymmetric spray penetration. The VCO nozzle’s large variation could be caused by eccentricity of the VCO nozzle inside and exaggerated by the low needle lift under low injection pressure operating condition. This is clearly illustrated in Figure 31.
Figure 32 shows a direct comparison of the mean minisac and VCO nozzle tip penetration for both 390 FN
nozzles with pilot injection. This shows that the minisac nozzle has a higher rate of penetration for the same injection conditions. This tendency is possibly due to the higher discharge coefficient of the minisac nozzle.(g) Effect of Single and Dual guide to penetration
The dual-guided VCO nozzle did not significantly improve the poor spray asymmetry of the single-guided VCO nozzle. This tendency is observed both with and without pilot injection. As illustrated in Figure 34, the measurement of the spray penetration length shows that the dual-guided VCO nozzle provides a faster spray tip penetration. (Figure 33, 34)
Figure 33.Different Nozzle Guide T ype and its Spray
Pattern (h) Effect of Common-rail Pressure to Penetration
Injection pressure is a key parameter in controlling the
spray penetration. Figure 35 and 37 show that a higher common-rail pressure results in a more rapid spray tip penetration. For Figure 35 test data were obtained for common-rail pressures of 600 bar, 800 bar, and 1200 bar
Penetration
Figure 36.Effect of Ambient Gas Pressure to Penetration
Figure 37.Effect of Injection Pressure and Ambient
Pressure on the Spray Penetration of the
Common-rail System, with Duration of 0.35
ms, Ambient Pressures of 17.2 and 27.6 bar,
and Injection Pressures of 300, 800, and
1350 bar
(i) Effect of Ambient Gas Pressure on Penetration Independent of the injection pressure, the spray tip penetration speed is reduced, as the ambient density is increased (Figure 36 & Figure 37). The increased droplet drag that is associated with higher gas density yields reduced penetration rates for both pilot and main sprays. The ambient nitrogen gas was pressurized to 17 bar, and to 27 bar with the temperature at 20 oC
3. Close to Nozzle Exit Spray Dynamics Observation Recent implementation of laser diagnostics has been shown to provide insight into the diesel spray processes. The motivation of this study is to visualize the spray structure of advanced diesel injection systems very close to the nozzle exit in an attempt to correlate the microscopic spray structure to the injection system performance and nozzle design. In the microscopic observation, the spray visualization was carried out by injecting fuel into atmosphere ambient condition or a room-temperature nitrogen-filled pressurized chamber.
(a) Spray Cone Angle and its Oscillation
Figure 38 shows a typical microscopic spray visualization results. The result shows rapid temporal variation of spray angle, which result into the puffy spray structure at the edge of the spray as observed in the macroscopic visualization in Figure 26. The results of the inclusive spray angles measured from all test cases are plotted in Figure 39, Figure 40 and Figure 41 for various injection pressures. Figure 39 shows spray angles of three tests with identical injection conditions. During the needle opening and closing period, the spray cone angles vary from test to test, however, during the needle fully open period, the spray angles stay fairly stable in the range of 30 to 50 degree. Similar result is found for the case of injection with 800 bar, as shown in Figure 40. During the needle fully open period, the spray angles are stable and in the range of 20 to 40 degree. For both of the cases injection with low pressure, as shown in Figure 41, the injection duration is not long enough for the needle to reach its fully open position; as a result, the needle is only partly open and the spray angle oscillates from start to end of injection. This inconsistency and oscillation of spray angle could be attributed to uncertainty of needle positioning in horizontal direction that establishes inconsistent internal flow within the nozzle.
Figure 38.Microscopic Visualization of Common-rail
Spray; Injection pressure: 300 bar, Injection
event: 0.3ms-Pilot/1.0ms-Dwell/1.2ms-Main,
Time between Frame: 0.04ms. (Frame 19 to
24 skipped)
Figure 39.Correlation between Spray Cone Angle and Needle Lift of Common-rail Pressure of 1350
bar and Duration of 1.2 ms.
Figure 40.Correlation between Spray Cone Angle and
Needle Lift of Common-rail Pressure of 800 bar and Duration of 1.2 ms.
Figure 41.Correlation between Spray Cone Angle and
Needle Lift of Main Injection of Common-rail System, with Pressure of 250 and 300 bar and Duration of 1.0 and 1.2 ms.(b) Spray Characteristics at Start of Injection
Figure 42 shows two typical transient microscopic visualization of the VCO nozzle at 300-bar common-rail pressure. A very fast transition from clear liquid column to milky spray was also observed, which, however, was not observed at higher-pressure cases. The penetration velocity of these early development sprays is ranging from 4 to 12 m/s.
(c) Spray Characteristics at End of Injection
Figure 43 shows the visualization results of end of injection with common-rail pressure of 300, 800, and 1350 bar, respectively. Significant liquid ligament sustaining for long period of time, about 0.32 ms, was observed in the case of low-pressure injection. Large size drops moving with low velocity , about 6 m/s, are also observed. As the pressure increase to 800 and 1350 bar,the situation is improved. The number and size of drops and the hanging-around period of liquid ligament are reduced as the injection pressure increases.
Figure 42.Initial Spray Breakup of Common-rail Spray,
with Injection Pressure of 300 bar; Injection Event: 0.3ms-Pilot/0.45ms-Dwell/1.2ms-Main; Time between Frame: 0.04 ms.
CONCLUSIONS
Both injection-rate measurement and spray visualization were performed to investigate injection dynamics and spray structure of minisac and VCO nozzle using HPCR system under high injection pressure. The deduced results are as follows:
1.The injection-rate is strongly dependent on the common-rail pressure, the nozzle hole diameter, and the nozzle type.
2.Pilot injection and dwell duration strongly affect the main injection in terms of needle lift and the injected fuel amount.
3.The maximum needle lift and initial needle opening rate are functions of the common-rail pressure.
4.The minisac nozzle has a higher discharge coefficient (Cd) than the VCO nozzle tip. The minisac nozzle can be utilized at a lower rail pressure and a shorter pilot injection duration, whereas the VCO nozzle cannot provide a consistent pilot injection at lower rail pressures.
5.The spray symmetry and spray structure depends on nozzle type. In general, the VCO nozzle has an asymmetric spray plume, but exhibits better spray spread and fuel-air mixing, as indicated by the observed larger spray angle. The large variation observed on the common-rail sprays could be caused by eccentricity of the VCO nozzle inside and exaggerated by the low needle lift under low injection pressure operating condition. The minisac nozzle exhibits a more symmetric spray penetration and a faster spray penetration rate.
Figure 43.Effect of Injection Pressure on End of
Injection of Common-rail System; 390 FN
VCO Nozzle, Injection Duration: 1.2ms-Main
Injection.
Left : 1350 bar Common-rail Pressure
Middle : 800 bar Common-rail Pressure
Right: 300 bar Common-rail Pressure
6.The VCO dual-guided nozzle does not significantly
improve the spray symmetry over that obtained with the VCO single-guided nozzle. However, the dual-guided nozzle does exhibit a faster average spray penetration than does the single-guided nozzle.
7.The spray tip penetration model correlates fairly well
with the measured data of common-rail sprays under various injection and ambient pressures, except for the common-rail sprays with injection pressure of 300 bar. Meanwhile, for the spray, the model tends to over predict the early phase of the penetration and under predict that of the later phase.
8.The nozzle orifice geometry significantly affects the
liquid spray-tip penetration. The data obtained show that the liquid spray tip penetration mainly depends on the nozzle tip type, needle guide type, injection pressure, ambient gas pressure.
9.For the high-pressure common rail system tested,
the spray cone angle shows conspicuous oscillation during pilot or main injection period, possibly due to needle eccentricity and oscillation.
ACKNOWLEDGMENTS
The financial support from ARO (Grant DAAH04-96-1-045), and Sandia National Laboratory (contract LF-5224), and the UM Automotive Research Center to Wayne State University are greatly appreciated. REFERENCES
1.Bosch, Wilhelm, (1966) "The Fuel Rate Indicator; A
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目录 第一章编制说明 (2) 第一节编制目的： (2) 第二节编制依据： (2) 第三节本工程施工采用的主要标准： (3) 第二章工程概况及特点 (4) 第一节工程基本情况： (4) 第二节工程概况： (4) 第三节工程特点 (5) 第三章施工总体部署 (5) 第一节实施目标 (5) 第二节施工顺序 (6) 第三节施工准备计划 (6) 第四节施工组织管理 (10) 第四章工期和进度计划及进度保证措施 (14) 第一节工期目标 (15) 第二节施工进度计划安排 (15) 第三节施工进度计划控制 (15) 第四节施工进度计划保证措施 (16) 第五节强化施工进度计划管理和协调 (22) 第六节定期生产检查及生产会议 (23) 第七节生产资金的保证 (24) 第八节建立监督机制 (24) 第五章钢结构施工方案及工艺 (24) 第一节钢结构深化设计方案 (24) 第二节钢结构制作 (29) 第三节包装、运输、装卸及堆放 (37) 第四节主要构件制作工艺 (39) 第五节钢结构安装 (44)
第六章主要技术措施 (67) 第一节焊接质量控制 (67) 第二节吊装质量保证措施 (71) 第七章工程质量、质量保证措施及质保体系 (73) 第一节质量目标及质量计划 (73) 第二节项目部质量管理责任 (74) 第三节质量计划控制点设置 (76) 第四节施工过程质量控制 (78) 第五节抓分项工程的质量管理 (82) 第六节施工质量检验与评定 (84) 第七节最终交工检查验收 (87) 第八章施工安全和安全保证措施 (88) 第一节安全目标 (88) 第二节安全管理的意义 (88) 第三节安全管理的原则: (88) 第四节安全管理手段 (88) 第五节安全管理体系(见下图) (89) 第六节安全生产岗位责任制 (90) 第七节安全生产保证措施 (105) 第九章文明施工 (122) 第一节文明施工目标： (122) 第二节建立文明施工领导小组。 (123) 第三节文明施工管理措施 (123) 第四节场容场貌管理措施： (124) 第五节现场卫生管理措施： (125) 第六节现场队伍精神风貌及管理措施： (125)
项目管理方法和项目实施方法的关系 在一个项目的执行过程中还同时需要两种方法：项目管理方法 和项目实施方法。 项目实施方法指的是在项目实施中为完成确定的目标如某个应 用软件的开发而采用的技术方法。项目实施方法所能适用的项目范围会更窄些，通常只能适用于某一类具有共同属性的项目。而在有的企业里，常常把项目管理方法和项目实施方法结合在一起，因为他们做的项目基本是属于同一种类型的。 实际上，只要愿意，做任何一件事情，我们都可以找到相应的 方法，项目实施也是一样。以IT行业的各种项目为例，常见的IT项目按照其属性可以分成系统集成、应用软件开发和应用软件客户化等，当然，也可以把系统集成和应用软件开发再分解成一些具备不同特性的项目。系统集成和应用软件开发的方法很显然是不一样的，比如说：系统集成的生命周期可能会分解为了解需求、确定系统组成、签订合同、购买设备、准备环境、安装设备、调试设备、验收等阶段;而应 用软件的开发可能会因为采用的方法不同而分解成不同的阶段，比如说采用传统开发方法、原型法和增量法就有所区别，传统的应用软件开发的生命周期可能分解成：了解需求、分析需求、设计、编码、测试、发布等阶段。 至于项目管理，可以分成三个阶段：起始阶段，执行阶段和结 束阶段。其中，起始阶段是为整个项目准备资源和制定各种计划，执
行阶段是监督和指导项目的实施、完善各种计划并最终完成项目的目标，而结束阶段是对项目进行总结及各种善后工作。 那么，项目管理方法和项目实施方法的关系是什么呢?简单的说，项目管理方法是为项目实施方法得到有效执行提供保障的。如果站在生命周期的角度看，项目实施的生命周期则是在项目管理的起始阶段和执行阶段，至于项目实施生命周期中的阶段分布是如何对应项目管理的这两个阶段，则视不同项目实施方法而不同。 一、实际意义 项目管理方法和项目实施方法对项目的成功都是有重要意义的，两者是相辅相成的，就如管理人员和业务技术人员对于企业经营的意义一样。从IT企业的角度看，任何一个IT企业如果要生产高质量的软件产品或者提供高质量的服务，都应该对自身的项目业务流程进行必要的分析和总结，并逐步归纳出自己的项目管理方法及项目实施方法，其中项目实施方法尤其重要，因为大部分企业都有自己的核心业务范围，其项目实施方法会比较单一，在这种情况下，项目管理方法可能会弱化，而项目实施方法会得到强化，两者会较紧密的结合在一起。只有总结出并贯彻实施符合企业自身业务的方法，项目的成功才不会严重依赖于某个人。在某种程度上，项目管理方法和项目实施方法也是企业文化的一部分。 从客户的角度看，如果希望得到有保障的产品或服务，那就既 需要关注提供产品或服务的企业是否有恰当的项目管理方法和项目 实施方法，也必须尊重该企业的项目管理措施与方法。
数字化校园建设与管理办法 第一章总则 第一条为加强学校数字化校园的建设和管理，规范数字化校园建设各项工作，提高学校信息化应用水平，保证信息化建设的实效性与可持续发展，实现学校信息资源和软硬件资源的有机集成和共享，充分发挥信息化建设成果在人才培养、科学研究、社会服务和文化传承创新等方面的支撑作用，根据相关的法律法规、国家和教育部对教育信息化建设的指导意见，以及《教育信息化十年发展规划2011—2020》、《陕西省教育信息化十年(2011—2020年)发展规划》、《陕西省教育信息化建设三年行动计划》等有关精神，特制定本办法。 第二条学校数字化校园建设，在学校信息化建设领导小组的领导下，由教务处信息中心统一规划、统一审批、统一建设、统一管理，并按照整体规划、分步实施的原则，以应用为中心，以数字资源建设为重点，逐步达到为师生、领导和管理部门提供良好的服务和辅助决策的建设目标，提升学校的综合竞争力。 第三条本办法适用于全校范围内各部门所拥有或负责管理运行的与数字化校园相关的基础网络、信息化公共平台、数字教育资源、管理信息系统、网站、数字监控网络及其相关网络接入设备、服务器、大容量存储设备等的建设和管理。 第二章管理机构与工作职责 第四条信息化建设领导小组是全面推进学校数字化校园建设的
最高管理与决策机构，负责审议学校数字化校园建设发展的中长期规划与经费预算；负责审议学校数字化校园建设、运维管理及校园网安全规章制度；明确学校数字化校园建设中各部门的责任分工、资源分配以及考核机制；对学校数字化校园建设中的重大问题和政策性问题进行决策。 第五条学校信息化建设领导小组负责对学校教育信息化建设发展的中长期规划进行论证，对数字化校园提出意见和建议；对学校数字化校园建设发展战略、政策、规划和发展中的重大问题提出建议和咨询意见；对学校数字化校园建设进程中各子项目的建设与验收提供技术层面与应用层面的意见或建议；指导学校数字化校园建设和信息化教育新模式的探索和研究工作。 第六条信息中心是学校数字化校园建设与管理具体实施的主体部门，全面负责学校数字化校园建设和管理工作。负责制定学校数字化校园建设发展的中长期规划与经费预算，制定学校数字化校园建设、运行与管理及保障校园网安全的规章制度；负责组织、实施学校数字化校园各项建设工作；负责对学校数字化校园建设相关项目和各部门申报的信息化新建和改造项目进行审核和实施；负责学校信息编码规范和数据标准的制定；负责学校信息资源共享、信息资源整合和系统集成；为各部门信息化建设提供技术指导、支持、监督和评比；负责公共平台应用的推广与培训；负责健全和完善信息化工作管理体系。 第七条各部门信息管理员负责本部门信息化相关数据的收集、整理和上报，负责本部门网站信息的更新、备份和维护；网络协管员
操作系统】Windows XP sp3 VOL 微软官方原版XP镜像◆ 相关介绍： 这是微软官方发布的，正版Windows XP sp3系统。 VOL是Volume Licensing for Organizations 的简称，中文即“团体批量许可证”。根据这个许可，当企业或者政府需要大量购买微软操作系统时可以获得优惠。这种产品的光盘卷标带有"VOL"字样，就取 "Volume"前3个字母，以表明是批量。这种版本根据购买数量等又细分为“开放式许可证”(Open License)、“选择式许可证(Select License)”、“企业协议(Enterprise Agreement)”、“学术教育许可证(Academic Volume Licensing)”等5种版本。根据VOL计划规定， VOL产品是不需要激活的。 ◆ 特点： 1. 无须任何破解即可自行激活，100% 通过微软正版验证。 2. 微软官方原版XP镜像，系统更稳定可靠。 ◆ 与Ghost XP的不同： 1. Ghost XP是利用Ghost程序，系统还原安装的XP操作系统。 2. 该正版系统，安装难度比较大。建议对系统安装比较了解的人使用。 3. 因为是官方原版，因此系统无优化、精简和任何第三方软件。 4. 因为是官方原版，因此系统不附带主板芯片主、显卡、声卡等任何硬件驱动程序，需要用户自行安装。 5. 因为是官方原版，因此系统不附带微软后续发布的任何XP系统补丁文件，需要用户自行安装。 6. 安装过程需要有人看守，进行实时操作，无法像Ghost XP一样实现一键安装。 7. 原版系统的“我的文档”是在C盘根目录下。安装前请注意数据备份。 8. 系统安装结束后，相比于Ghost XP系统，开机时间可能稍慢。 9. 安装大约需要20分钟左右的时间。 10. 如果你喜欢Ghost XP系统的安装方式，那么不建议您安装该系统。 11. 请刻盘安装，该镜像用虚拟光驱安装可能出现失败。 12. 安装前，请先记录下安装密钥，以便安装过程中要求输入时措手不及，造成安装中断。 ◆ 系统信息：
1．柴油机特性曲线：用曲线形式表现的柴油机性能指标和工作参数随运转工况变化的规律。2．扫气过量空气系数：每一循环中通过扫气口的全部扫气量与进气状态下充满气缸工作容积的理论容气量之比 3．封缸运行：航行时船舶柴油机的一个或一个以上的气缸发生了一时无法排除的故障，所采取的停止有故障气缸运转的措施。 4．12小时功率：柴油机允许连续运行12小时的最大有效功率。 5.有效燃油消耗率：每一千瓦有效功率每小时所消耗的燃油数量。 6．示功图：是气缸内工质压力随气缸容积或曲轴转角变化的图形。 7．燃烧过量空气系数：对于1kg燃料，实际供给的空气量与理论空气需要量之比。 8．敲缸：柴油机在运行中产生有规律性的不正常异音或敲击声的现象。 9．1小时功率：柴油机允许连续运行1小时的最大有效功率。（是超负荷功率，为持续功率的110%。） 10.平均有效压力：柴油机单位气缸工作容积每循环所作的有效功。 11.热机：把热能转换成机械能的动力机械。 12.内燃机：两次能量转化（即第一次燃料的化学能转化成热能，第二次热能转化成机械能）过程在同一机械设备的内部完成的热机。 13.外燃机： 14.柴油机：以柴油或劣质燃料油为燃料，压缩发火的往复式内燃机。 15.上止点：活塞在气缸中运动的最上端位置，也是活塞离曲轴中心线最远的位置。下止点 16.行程：活塞从上止点移动到丅止点间的位移，等于曲轴曲柄半径R的两倍。 17.气缸工作容积：活塞在气缸中从上止点移动到丅止点时扫过的容积。 18.压缩比：气缸总容积与压缩室容积之比值，也称几何压缩比。 19.气阀定时：进排气阀在上.丅止点前启闭的时刻称为气阀定时，通常气阀定时用距相应止点的曲轴转角表示。 20.气阀重叠角：同一气缸在上止点前后进气阀与排气阀同时开启的曲轴转角。（进排气阀相通，依靠废气流动惯性，利用新鲜空气将燃烧室内废气扫出气缸） 21.扫气：二冲程柴油机进气和排气几乎重叠在丅止点前后120-150曲轴转角内同时进行，用新气驱赶废气的过程。 22.直流扫气：气流在缸内的流动方向是自下而上的直线运动。（空气从气缸下部扫气口，沿气缸中心线上行驱赶废气从气缸盖排气阀排出气缸） 23.弯流扫气：扫气空气由下而上，然后由上而下清扫废气。 24.横流扫气：进排气口位于气缸中心线两侧，空气从进气口一侧沿气缸中心线向上，然后再燃烧室部位回转到排气口的另一侧，再沿中心线向下，把废气从排气口清扫出气缸。 25.回流扫气：进排气口在气缸下部同一侧，排气口在进气口上方，进气流沿活塞顶面向对侧的缸壁流动并沿缸壁向上流动，到气缸盖转向下流动，把废气从排气口中清扫出气缸。 26.增压：提高气缸进气压力的方法，使进入气缸的空气密度增加，从而增加喷入气缸的燃油量，提高柴油机平均有效压力和功率。 27.指示指标：以气缸内工作循环示功图为基础确定的一些列指标。只考虑缸内燃烧不完全及传热等方面的热损失，不考虑各运动副件存在的摩擦损失，评定缸内工作循环的完善程度。 28.有效指标：以柴油机输出轴得到的有效功为基础，考虑热损失，也考虑机械损失，是评定柴油机工作性能的最终指标。 29.平均指示压力：一个工作循环中每单位气缸工作容积的指示功。 30.指示功率：柴油机气缸内的工质在单位时间所做的指示功。 31.有效功率：从柴油机曲轴飞轮端传出的功率。
天津市东丽区职业教育中心学校“数字校园实验校”建设实施方案 一、信息化发展战略定位和愿景 根据学校十三五战略发展规划，在国家级示范校的基础上，立足东丽，面向天津，辐射全国，走向世界，实现“工学结合高要求、专业建设高品位、教育教 学高质量、就业服务高水平、学校发展高效益”的五高目标，“十三五”末期实现学校向世界一流水平的跨越，充分发挥示范和辐射作用。通过本期数字化校园项目建设，将我校打造成全国一流的中职数字化校园，构建技术先进、扩展性强、安全可靠、高速畅通、覆盖全校的校园网络环境。 建立一整套校园信息管理系统，为实现“环境数字化、管理数字化、教学数 字化、产学研数字化、学习数字化、生活数字化”提供全面的系统支持，使之成 为一个全面、集成、开放、安全的信息系统，成为一个网络化、数字化、智能化、虚拟化的新型教育、学习、实训和管理平台。通过数字化校园项目建设，推动教学模式变革，提高人才培养质量，促进学校对外交流。通过项目建设，使全体师 生提高信息化思维能力，养成信息化行为方式，遵守信息化交往规则，发展信息化职业能力。 二、数字化校园建设目标 按照“顶层设计、统一标准、数据共享、应用集成、硬件集群（虚拟化）” 的规划建设理念，实现： 1.为教学、科研、管理、生活提供一个开放、协同、高效、便捷的数字化 环境，实现规范高效的管理 2.为领导的决策提供实时有效的信息依据 3.为提升学校的核心竞争力，实现学校的跨越式发展提供有力的支撑 具体目标就是实现“六个数字化”： 环境数字化：构建结构合理、使用方便、高速稳定、安全保密的基础网络。 在此基础上，建立高标准的共享数据中心和统一身份认证及授权中心，统一门户平台以及集成应用软件平台，为实现更科学合理的数字化环境打下坚实的基础。 管理数字化：构建覆盖全校工作流程的、协同的管理信息体系，通过管理信息的同步与共享，畅通学校的信息流，实现管理的科学化、自动化、精细化，突出以人为本的理念，提高管理效率，降低管理成本。 教学数字化：构建综合教学管理的数字化环境，科学统一的配置教学资源， 提高教师、教室、实训室等教学资源的利用率，改革教学模式、手段与方法，丰 富教学资源，提高教学效率与质量。 产学研数字化：构建数字化产学研信息平台，为产学研工作者提供快捷、全面、权威的信息资源，实现教学、科研和实训一体化，提供开放、协同、高效的
Windows7 SP1官方原版 以下所有版本都为Windows7 SP1官方原版，请大家放心下载！ 32位与64位操作系统的选择：https://www.doczj.com/doc/0c18002332.html,/Win7News/6394.html 最简单的硬盘安装方法：https://www.doczj.com/doc/0c18002332.html,/thread-25503-1-1.html 推荐大家下载旗舰版，下载后将sources/ei.cfg删除即可安装所有版本，比如旗舰，专业，家庭版。 ============================================ Windows 7 SP1旗舰版中文版32位： 文件cn_windows_7_ultimate_with_sp1_x86_dvd_u_677486.iso SHA1:B92119F5B732ECE1C0850EDA30134536E18CCCE7 ISO/CRC:76101970 cn_windows_7_ultimate_with_sp1_x86_dvd_u_677486.iso.torrent(99.63 KB, 下载次数: 326189) Windows 7 SP1旗舰版中文版64位： 文件cn_windows_7_ultimate_with_sp1_x64_dvd_u_677408.iso SHA1: 2CE0B2DB34D76ED3F697CE148CB7594432405E23 ISO/CRC: 69F54CA4 cn_windows_7_ultimate_with_sp1_x64_dvd_u_677408.iso.torrent(128.17 KB, 下载次数: 197053)
项目管理思路（提纲） 原则：规范创新项目管理方法，提供标准化的项目管理体系。（这次的思路主要考虑整体、不突出重点。） 一、工程项目管理的基本内容： 1、项目部管理 2、前期管理 3、招标合同管理 4、设计管理 5、总承包管理 6、进度管理 7、质量管理 8、成本管理 9、竣工（收尾）管理 二、项目部管理 1、项目部组织结构：项目部的构成根据项目的发展进度再不断进行调整，先补充预算员、资料员及熟悉酒店项目的机电工程师； 2、项目部职责（分工）：落实责任到岗位，落实责任到人，着重把后面的所有管理内容一项不漏的分配到具体的管理人员上，真正做到“权责明晰，有据可依”； 3、加强项目管理人员的培训及学习工作，紧跟社会行业的前进步伐，提高项目管理人员的业务能力，为新项目的顺利进行提供坚实的基
础； 4、项目部管理制度：以公司现有的规章制度及考核制度为基础，再根据新情况进行一些适当补充与调整。 三、前期管理 1、各种手续、审批报建工作的推进及跟踪，无法办理的事项及时将具体情况及原因反馈给公司领导； 2、联络街道办和公证处对本项目周边毗邻建筑物的现状（特别是裂缝、下沉）进行拍照确认并公证； 3、拆除施工场地内的原有基础或其他障碍物；通水(自来水公司)、通电、办理临时占道、开路口(城管局) 及其他相关手续； 4、根据公司领导的要求及项目实际情况编制项目总开发计划； 四、招标合同管理 1、除审查入围单位的资质等级、营业执照、财务状况外，还应着重对入围单位的办公地点、在建项目（生产厂房）针对人员、质量、安全、环境等进行实地考察，以确定是否满足我方质量、进度等综合要求； 2、根据总开发计划编制专业分包与主要材料、设备的进场计划，明确进场时间；根据专业分包与主要材料、设备的进场计划编制招标、采购计划，并严格执行； 3、对于专业分包，要细化、深化各类发包工程内容的自身招标条件，应事先研究各工程内容建设的时间、验收、保修、交接、资料、协作、费用、安全、场地等接口配合条件，就甲方发包(含总承包)的各内容
项目一：数字化校园特色项目建设计划 一、需求论证 信息技术的飞速发展，迅速地改变着人们的学习、工作和生活，也改变着人们的思想、观念和思维方式。这一切都对快速发展中的职业教育和职业学校提出了十分严峻的挑战。现代信息技术正在向职业学校教学、科研、管理的每一个环节渗透，将改变传统的教学模式并大幅度提高教育资源的利用效率。数字化校园、网上学校已被人们熟悉，职业教育正在走向全面的信息化。 数字化校园的建设应用是教育系统信息化的关键，在职业学校建设数字化校园，对于促进教师和学生尽快提高应用信息技术的水平,促进学校教学改革，推行素质教育，促进教学手段的现代化水平,为教师提供一种先进的辅助教学工具、提供丰富的资源库，全面提高学校现代化管理水平，加强学校与外界交流等方面都具有重要作用。 2005年学校完成校园网建设，同时接入因特网，校园网覆盖了所有使用计算机的实验室、各处办公室、各专业组。目前校园网已覆盖整个校园。但数字化教与学以及服务区域职业教育、实现教育资源共享的能力还远远不够。作为一所综合性国家级重点职业学校，以及建设国家中等职业教育改革发展示校的要求，要使其发挥辐射带动作用，达到资源利用最大化，迫切需要我校建设数字化校园，将更大的注意力放在信息化的深入应用上，及早做好规划，将信息化发展推向新水平。 二、建设目标
数字化校园建设的目标主要包括：一是完善校园网基础设施建设，构建技术先进、扩展性强、安全可靠、高速畅通、覆盖本部、一分部、实训基地的校园网络环境；二是建设全校防盗系统；三是完善校园广播系统；四是各种资源应用平台建设；五是建设校园一卡通。 学校通过构建技术先进、扩展性强、安全可靠、高速畅通、覆盖全校的校园网络环境，建立全校公共信息系统，为教与学提供先进数字化管理手段，提高管理效率；建立功能齐全的教学管理系统；配合“工学结合”教学模式，建设容丰富的网络教学资源平台，实现数据资源共享，提高全校师生的信息化水平素养。通过数字化校园的建设项目，为培养高技能应用型人才和服务社会搭建公共服务平台。 三、建设思路 以服务专业建设为出发点，建设数字化校园和教学资源中心。构筑信息交流与资源共享平台，创建开放的教学资源环境，实现优质教学资源网上共享，为实用型技能人才的培养和构建现代化学习环境搭建公共平台，提高管理效率与教学水平。提高全校师生信息化水平素养，以网络为基础，利用先进的信息手段和工具，将学校的各个方面，实现环境（包括网络、设备、教室等）、资源（如图书、讲义、课件等）、活动（包括教、学、管理、服务、办公等）的数字化，逐步形成一个数字校园空间，从而使现实校园在时间和空间上获得延伸，完成数字校园建设，对本地区职业教育信息化建设和发展起到示与带动作用。 四、建设容 （一）校园安全防盗系统
Microsoft 微软官方原版（正版）系统大全 微软原版Windows 98 Second Edition 简体中文版 https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16446&page=1&extra=#pid125031 微软原版Windows Me 简体中文版 https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16448&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版Windows 2000 Professional 简体中文版 https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16447&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版Windows XP Professional SP3 简体中文版 https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16449&page=1&extra=#pid125073微软原版Windows XP Media Center Edition 2005 简体中文版 https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16451&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版Windows XP Tablet PC Edition 2005 简体中文版 https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16450&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版Windows Server 2003 R2 Enterprise Edition SP2 简体中文版(32位) https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16452&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版Windows Server 2003 R2 Enterprise Edition SP2 简体中文版(64位) https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16453&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版Windows Vista 简体中文版(32位) https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16454&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版Windows Vista 简体中文版(64位) https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16455&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版 Windows7 SP1 各版本下载地址： https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=12387&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版 Windows Server 2008 Datacenter Enterprise and Standard 简体中文版(32位) https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16457&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版 Windows Server 2008 Datacenter Enterprise and Standard 简体中文版(64位) https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16458&highlight=%CE%A2%C8%ED%D4%AD %B0%E6 微软原版 Windows Server 2008 R2 S E D and Web 简体中文版(64位) https://www.doczj.com/doc/0c18002332.html,/viewthread.php?tid=16459&highlight=%CE%A2%C8%ED%D4%AD %B0%E6
中国建设银行科技应用规划项目项目管理章程和工作方法 中国建设银行 2020年4月2日
目录 1项目人员角色和职责3 2项目运行中的沟通机制 (5) 3项目文档资料管理机制8 4项目人员的考核机制 (12) 5项目培训机制 (14) 6项目验收机制15 项目人员角色和职责 项目领 导委员会 项目总监 /项目管理办公 项目小组 项目领 导委员会 项目总监 质量总监 项目经理 项目小组 1) 项目领导委员会：
由双方的高层领导参加，直接负责项目的成功实施，负责： a)确定项目目标和方向 b)保证资源合理调动，支持项目的推行 c)促使管理层对项目的全力参与和支持 d)验收和审批项目成果 e)授权项目经理开展工作 2)项目总监和质量总监： 项目总监由双方选出的高层领导担任，主要负责： a)对项目过程进行指导和监督 b)确认双方工作职责和安排 c)组织协调项目所需资源的合理调配 d)按项目进度向项目领导委员会汇报 e)定期对项目的工作进度进行监督 f)对项目成果进行确认和验收 毕博管理咨询将另派高层管理人员作为本项目的质量总监，主要负责： a)对本项目的整体质量进行检查和考核 3)项目经理： 项目经理成员由双方的项目经理组成，具体负责： a)策划项目推进和控制项目进程 b)确认项目小组及其成员的工作职责 c)指导及安排项目小组的日常工作 d)定期安排双方沟通、及时调整工作安排 e)现场处理双方可能产生的意见不一致 f)执行项目所需资源的有效调配 g)组织对项目成果的确认和验收 4)项目小组：
项目小组将由小组负责人、咨询顾问、行业专家以及中国建设银行的项目参与人员共同组成。项目小组的职责包括： a)确定项目的工作步骤和具体工作方法 b)具体开展项目工作，包括：收集数据和信息，分析并确定问题，设计解决方案， 讨论和修改工作成果，协助实施 c)根据项目要求，在规定的时间内提交符合质量要求的项目设计方案 项目运行中的沟通机制
第一章船舶动力装置系统 现代船舶动力装置，按推进装置的形式，可分为5大类： （1）·柴油机推进动力装置；（2）·汽油机推进动力装置；（3）·燃气轮机推进动力装置；（4）·核动力推进动力装置；（5）·联合动力推进装置。 现代民用船舶中，所采用的动力装置系统绝大多数是柴油机动力装置，因此，本书主要介绍以柴油机为动力装置的船舶，图1－1为船舶柴油机动力装置系统燃油供应系统原理图。 图1－1 柴油机动力装置系统燃油供应系统原理图 柴油机燃油系统包括三大功能系统，分别是输送、日用和净化。 1）油输送系统 燃油输送系统是为了实现船上各燃油舱柜间驳运及注入排出而设计的，所以，系统应包括燃油舱柜、输送泵、通岸接头和相应的管子和阀件。通过管路的正确连接和阀件的正确设置，实现规格书所要求的注入、调拨和溢流等功能。 设计前，要认真阅读规格书和规范的有关章节，落实本系统所涉及的舱柜和设备所要求的输送功能。 设计时，应注意如下几个方面： a.规格书无特殊要求，注入管应直接注入至各储油舱，再通过输送泵送至各日用柜和沉淀柜，各种油类的注入总管应设有安全阀，泄油至溢流舱，泄油管配液流视察器； b.所有用泵注入的燃油舱柜都要有不小于注入管直径的溢流管，溢流至相应的溢流舱或储油舱，具体规定见各船级社规范，溢流管要配液流视察器； c.从日用柜至沉淀柜的溢流，在日用柜哪的管子上都要开透气孔以防止虹吸作用，两柜的连接管处要有液流视察器。 d.装在日用柜和沉淀壁上低于液面的阀，有的船级社规范对其材料有具体的规定，选阀时应予以注意。 e.一般情况下输送系统的介质，温度和压力都是较低的，所以系统的管材选用III级管即可。
中小学数字化校园管理系统软件 拟 定 方 案
目录 一、数字校园基础平台： (3) 二、协同办公系统： (5) 三、招生管理系统： (6) 四、学籍管理系统： (7) 五、学费管理系统： (7) 六、学生管理系统： (8) 七、学生请销假管理： (8) 八、量化考核管理系统： (8) 九、教务管理系统： (9) 十、成绩管理系统： (9) 十一、离校管理系统： (10) 十二、资产管理系统： (10) 十三、人事档案管理系统： (11) 十四、数字化图书馆教学资源库、精品课程及网上教学平台： (11)
“数字化校园管理系统” “数字校园管理系统”是针对职业院校信息化建设，研发的数字化校园管理系统。通过电脑或手机等终端，为校长、老师、学生、行政办公人员、学生父母、来访用户及相关应用人员提供高效、便捷的一站式信息服务。实现了校园内各类应用软件高效集成和数据资源高度共享，是最适合中学高中及大学校园信息化建设的管理软件。 下面是平台界面示意图： 一、数字校园基础平台：
数字校园管理系统特点： 产品开发以学校为原型， 技术选型性价比更高。 采用windows server +php + mysql + apache的技术架构。 优势：采用win server 作为操作系统，更容易维护，也符合学校服务器现有情况 采用mysql开源数据库，无需支付软件授权费用，因为mysql是一个开源免费的数据库。但是其性能及稳定性堪称一流，许多大型网站系统都在使用。 PHP是全世界使用量排名第四的编程语言，在B/S结构的系统中有其得天独厚的优势。 我方在提供以开发完毕的整套系统的基础上，后期可根据学校需求进行系统的第二次开发，以适应学校的需求。 数字校园管理系统：多终端访问： 数字校园管理系统基础平台包含内容：
精心整理正版Windows系统下载+正版密钥 2010-05-3011:49 喜欢正版Windows系统 这是我收集N天后的成果，正版的Windows系统真的很好用，支持正版！大家可以用激活工 具激活！现将本收集的下载地址发布出来，希望大家多多支持！ Windows98第二版（简体中文） 安装序列号：Q99JQ-HVJYX-PGYCY-68GM3-WXT68 安装序列号：Q4G74-6RX2W-MWJVB-HPXHX-HBBXJ 安装序列号：QY7TT-VJ7VG-7QPHY-QXHD3-B838Q WindowsMillenniumEdition(WindowME)（简体中文） 安装序列号：HJPFQ-KXW9C-D7BRJ-JCGB7-Q2DRJ 安装序列号：B6BYC-6T7C3-4PXRW-2XKWB-GYV33 安装序列号：K9KDJ-3XPXY-92WFW-9Q26K-MVRK8 Windows2000PROSP4（简体中文） SerialNumber:XPwithsp3VOL微软原版（简体中文） 文件名:zh-hans_windows_xp_professional_with_service_pack_3_x86_cd_vl_x14-74070.iso 大小:字节 MD5:D142469D0C3953D8E4A6A490A58052EF52837F0F CRC32:FFFFFFFF 邮寄日期(UTC)：5/2/200812:05:18XPprowithsp3VOL微软原版（简体中文）正版密钥： MRX3F-47B9T-2487J-KWKMF-RPWBY(工行版)（强推此号！！！） QC986-27D34-6M3TY-JJXP9-TBGMD(台湾交大学生版) QHYXK-JCJRX-XXY8Y-2KX2X-CCXGD(广州政府版)
上海国际海事信息与文献网发布时间:2007-03-20 浏览:3123 【摘要】从船用柴油机的市场、产品、技术等方面介绍了柴油机的现状及发展动向。论述当前国外气缸直径160 mm以上，单机功率大于1000 kW的大功率低速、中速、高速柴油机的总体技术水平、技术发展概况，特别是在提高可靠性、改善其低工况特性、降低其排放和智能柴油机等方面进行阐述，并预测今后的发展趋势。 0 引言 柴油机因其功率范围大、效率高、能耗低、使用维修方便而优于蒸汽机、燃气轮机等，在民用船舶和中小型舰艇推进装置中确立了主导地位。船用柴油机的整体结构及其零部件结构不断改进，特别是电子技术、自动控制技术在柴油机上的应用，使其各项技术指标不断创新，市场上已有一批性能好、油耗低、功率范围大、废气排放符合法定标准、可靠性高的产品。 柴油机相对汽油机的最大优点在于高压缩比。这使最大功率、热效率提高，油耗降低；发动机坚固、耐用，寿命变长。但柴油机缺点在于比功率低于汽油机，对空气利用率低，摩擦损失大。 1 低速柴油机 低速柴油机由于性能优良、可靠性好、使用维护方便、能燃用劣质燃油等优点，已成为大型油船、大型干散货船、大型集装箱船的主要动力。最新型低速柴油机在许多方面趋于一致。即结构方面，采用非冷却式喷油器、可变喷油定时油泵、长尺寸连杆、液压驱动式排气门、单气门直流扫气、定压增压、高效涡轮增压器；性能方面，平均有效压力不断提高，增加活塞平均速度，改进零部件结构，增加强度，保持原有的低燃油消耗水平，使单缸功率不断增大，使用寿命延长。电子液压控制系统取代传统的机械式的凸轮驱动机构，简化柴油机设计，降低成本，优化运行控制。近年来，其爆发压力从8 MPa上升到16 MPa，燃油消耗率从208g/(kw·h)降至155g/(kw·h)左右。 目前世界船用低速柴油机市场仍被MAN B&W、Wartsila-New Sulzer和日本三菱重工三大公司垄断，以生产总功率来说，分别约占57％、33％和10％。 MAN B&W公司通过提高气缸平均有效压力和活塞平均速度来提高单缸功率。为使MC系列柴油机的NOx排放量降低，采用提高压缩比和可导致平稳燃烧的喷射系统等措施。 为了在减少NOx排放时不影响燃油消耗率，在设计时应考虑采用增加喷射压力、压缩比、燃烧压力、增压器效率等措施。MAN B&W 6L60MC型柴油机是世界上第一台正式投入使用的“智能化”主机，其燃油喷射和排气阀控制均通过电子计算机完成，达到了低油耗、NOx低排放的目标。 Wartsila-New Sulzer公司通过重组后，在开发、设计和制造能力方面骤然大增。RTA系列低速柴油机为该公司20世纪80年代开发，至今近20年来该公司通过提高平均有效压力、增加活塞平均速度，探索达到更大功率的可能性。 通过增大行程／缸径比，探索提高推进效率的方法；通过提高最大燃烧压力和可变燃油正
微软MSDN官方（简体）中文操作系统全下载 这不知是哪位大侠收集的，太全了，从DOS到Windows，从小型系统到大型系统，从桌面系统到专用服务器系统，从最初的Windows3.1到目前的Windows8，以及Windows2008，从16位到32位，再到64位系统，应有尽有。全部提供微软官方的校验文件，这些文件都可以在微软官方MSDN订阅中得到验证，完全正确！ 下载链接电驴下载，可以使用用迅雷下载，建议还是使用电驴下载。你可以根据需要在下载链接那里找到你需要的文件进行下载！太强大了！！！ 产品名称: Windows 3.1 (16-bit) 名称: Windows 3.1 (Simplified Chinese) 文件名: SC_Windows31.exe 文件大小: 8,472,384 SHA1: 65BC761CEFFD6280DA3F7677D6F3DDA2BAEC1E19 邮寄日期(UTC): 2001-03-06 19:19:00 ed2k://|file|SC_Windows31.exe|8472384|84037137FFF3932707F286EC852F2ABC|/ 产品名称: Windows 3.2 (16-bit) 名称: Windows 3.2.12 (Simplified Chinese) 文件名: SC_Windows32_12.exe 文件大小: 12,832,984 SHA1: 1D91AC9EB3CBC1F9C409CF891415BB71E8F594F7 邮寄日期(UTC): 2001-03-06 19:21:00 ed2k://|file|SC_Windows32_12.exe|12832984|A76EB68E35CD62F8B40ECD3E6F5E213F|/ 产品名称: Windows 3.2 (16-bit) 名称: Windows 3.2.144 (Simplified Chinese) 文件名: SC_Windows32_144.exe 文件大小: 12,835,440 SHA1: 363C2A9B8CAA2CC6798DAA80CC9217EF237FDD10 邮寄日期(UTC): 2001-03-06 19:21:00 ed2k://|file|SC_Windows32_144.exe|12835440|782F5AF8A1405D518C181F057FCC4287|/ 产品名称: Windows 98 名称: Windows 98 Second Edition (Simplified Chinese) 文件名: SC_WIN98SE.exe 文件大小: 278,540,368 SHA1: 9014AC7B67FC7697DEA597846F980DB9B3C43CD4 邮寄日期(UTC): 1999-11-04 00:45:00 ed2k://|file|SC_WIN98SE.exe|278540368|939909E688963174901F822123E55F7E|/ 产品名称: Windows Me 名称: Windows? Millennium Edition (Simplified Chinese) 文件名: SC_WINME.exe
康明斯柴油机简介 柴油机选用康明斯柴油发动机 康明斯公司成立于1919年，康明斯发动机是美国著名的三大品 牌（卡特比勒，康明斯，底特律）发动机之 一，自八十年代初进入中国以来，经过近二 十年的发展，已成为中国市场占有率最高的 进口发动机品牌，在中国客户当中具有较高 的知名度。在美国及美洲，卡特比勒以工程 机械著名，而康明斯则在车用和民用方面占 优势。 康明斯公司现已成为全球50匹马力以上 柴油机最大的生产厂家。康明斯公司在全世 界具有完善的销售和服务网络，在中国的重 庆和十堰设有合资制造厂。康明斯公司自92 年与江苏 星光发电设备有限公司合作，在发电机组市 场上取得了令人瞩目的成就。 康明斯柴油发电机组的基本特征： 技术先进，性能稳定可靠，工作寿命长 电子调速，独特的低压PT燃油喷射技术， 大大降低燃油系统故障率 遍布全国的专业服务网络，操作使用技术渐为中国可户所熟悉 油耗较低，运行成本低，功率范围由30KW-2200KW，产品规格齐全 发电机低电抗设计是非线性负载下的波形失真极小，并有良好的电动机启动能力。 发电机激磁系统能使机组在承受任何瞬间加载时，频率波动迅速恢复。 结构特点:直流电启动、四冲程、水冷、自带风扇、闭式循环冷却、进气中冷、废气涡轮增压。缸体设计坚固耐用，振动小，噪声小，直列 6 缸四冲程，运转平稳，效率高：可替换湿式气缸套，寿命长，维修方便；两缸一盖，每缸 4 气门，进气充分，性能卓越；强制水冷，热辐射小。
★重负载耐久性； ★杰出的瞬态响应性； ★采用电子调速器； ★电控系统采用DC24V,配备有停油电磁阀 优越性：与国内同类产品相比具有体积小、重量轻、油耗低、功率高、工作可靠，配件供应及维修方便的优势。采用电子调速器，具有冷却水温过高、机油压力低及超速报警并自动停车等保护功能。 优化设计： > 凸轮轴：大直径凸轴轮设计，可承受更高的负荷，精确控制气门和喷油正时；感应淬硬使凸轮寿命更长；优化设计的凸轮型线，使气六落座速度减缓，冲击力减小，减少磨损和振动，提高了发动要的可靠性和耐久性。 > 连杆：模锻连杆，杆身油道为活塞提供压力润滑油；杆身优化设计降低了单位应力。 > 冷却系统：采用皮带传动离心水泵。大流量水道为环绕气缸套、气门和喷油器的水腔提供均量的冷却水。旋转式水滤器含专用的干式化学添加剂 DCA4，可有效地防止气缸套穴蚀、水泵叶轮汽蚀及冷却系统零部件腐蚀、积垢等，控制冷却液的酸度，并去除杂质。 > 曲轴：高强度锻钢制造的整体式曲轴，采用高强化和高平衡精度工艺制造，曲轴圆角和轴颈采用先进的感应淬火处理技术，曲轴的疲劳强度更高。 > 气缸体：高强度合金铸铁制造，新型的缸体结构，使发动机刚性更好，密封性提高，振动减小，噪声降低。 > 气缸盖：每缸四气门设计，优化了空气/燃油的混合，改善燃烧和排放，发动机响应迅速，采用脉冲排气道，有利于废气能量的充分利用。高强度合金铸铁铸造，可以承受更高的冲击力，使发动机的超速能力更强，每两缸一个缸盖，维修、更换方便。 > 气缸套：可更换的湿式气缸套，比干式气缸套散热效果更好，更换容易而不需重镗气缸。