可变长度进气管原理
M [N m ]
P [k W ]
n [min ]
-1P =n ? M 9550
[kW]
Variable Intake Manifold in VR Engines
Principles and Description of Operation
Self-study programme 212
Service.
2
NEW
This self-study programme explains how it was possible to optimise the torque and output of the VR engine with the concept and design of the new intake manifold and just how an intake tract affects the air supply.
The VR6 engine, in which the conventional intake manifold has been replaced by the new variable intake manifold, provides an example which makes the increase in power and torque very clear.
A patent for the variable intake manifold
concept of the VR engine has been applied for.
The output and torque of an engine have the greatest effect on the engine’s character.These, in turn, are greatly affected by the degree to which the cylinder is filled and the geometric form of the intake tract.
High torque requires an intake manifold with a geometry different to one for high power output.A medium intake manifold length with a medium diameter represents a compromise, but a variable intake manifold is optimal.
212_020
3
Table of contents
Power and torque . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Air supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Air channelling in engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5The principle of resonance charging . . . . . . . . . . . . . . . . . . . . . . . . . . 5
The variable intake manifold of the VR engines. . . . . . . . . . . . . 8
Torque position of VR6 variable intake manifold . . . . . . . . . . . . . . . . 9Power position of VR6 variable intake manifold . . . . . . . . . . . . . . . . .10Power and output of VR6 engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Load-dependent change-over concept. . . . . . . . . . . . . . . . . . . . . . . . . 12Power collector and change-over barrel . . . . . . . . . . . . . . . . . . . . . . . 13Filling the power collector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Intake manifold change-over . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Intake manifold change-over valve N156 . . . . . . . . . . . . . . . . . . . . . . . 16
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Test your knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4
n ? M
9550
P =[kW] Power and torque
High power and high torque with low fuel con-
sumption are characteristics of a modern car
engine.
How was this goal achieved?
The power P is the product of engine speed n
and torque M.
Greater power can be attained through either
greater torque or higher engine speed.
The numerous moving masses in an engine
(pistons, connecting rods, crankshaft and so on)
limit engine speed.
Thus only torque remains to increase power.
To increase engine torque, one can increase the
displacement or the compression.
Because vehicle taxes are often assessed
according to displacement in spite of technical
advantages, the goal must be attained with a
given displacement in other ways, namely by
increasing the efficiency of the engine.
A flatter torque curve as a function of engine
speed thus becomes the ultimate measure.
One achieves maximum torque through
complete combustion of the fuel-air mixture at
the right moment.
But every complete combustion requires a
certain ratio between air and fuel. The engine
should be provided optimally with air at every
speed.
The volumetric efficiency (VE, represented as λL
in the graphics), makes a qualitative statement
about the air supply:
212_010
m a=actual air mass in cylinder in [kg]
m th=
theoretical air mass in [kg]
m L
m th
λL =
n=engine speed [rpm](min-1in graphics)
M=torque [Nm]
9550=constant derived from the calculation of
all factors when the numerical values for
nare entered in rpm and M, in Nm.
5
The air supply
Air channelling on engine
The intake system is responsible for feeding the engine with the air necessary for combustion.It ensures an even supply of air to all cylinders.Engines with carburettors or throttle-body injection also mix fuel with the air in the intake tract, and a fuel-air mixture is transported.Intake tracts of multi-point injection systems transport only air.
This opens substantially more possibilities for the designer to design the intake manifold in order to achieve better exploitation of the self-charging effect of gas momentum.
The principle of resonance charging
An intake system works according to the principle of resonance charging, that is, high and low-pressure waves are used to charge the cylinder, in order to achieve greater volumetric efficiency.
Consider the events in the intake tract.The inlet valve opens.
The piston moves downwards in the cylinder, in the direction of bottom dead centre (BDC).
It creates a low-pressure wave in the vicinity of the inlet valve.
Basic structure of an air channel on an engine
Air
Start of resonance charging
6The air supply
This low-pressure wave propagates itself though
the resonance pipe to the other end, which
protrudes into a collector.
The low-pressure wave at the end of the pipe
acts on the volume of air present in the collector.
The pressure of the volume of air in the collector
is approximately equal to ambient air pressure.
This is significantly higher than the air pressure at
the open end of the resonance pipe.
The low pressure now present at the end of the
pipe pulls along the air mass present here.
They force themselves simultaneously into the
resonance pipe so that where the low-pressure
wave was, an equally large high-pressure wave
develops, which propagates itself towards the
inlet valve.
This effect is also characterised in this way:
The low-pressure wave is reflected at the open
end of the pipe in the collector.
Propagation of low-pressure wave
Development of high-pressure wave
7
This high-pressure wave travels back through the resonance pipe and pushes the air mass past the still-open inlet valve into the cylinder.
This continues until the pressure before the inlet valve and the pressure in the cylinder are equal.The engine experiences “ram-effect” charging. The volumetric efficiency (see page 4) reaches values of about 1.0 and even above.
As a result, when the inlet valve closes, backflow of the ram-effect charging into the intake pipe is prevented.
The time t (in milliseconds) required by the low and high-pressure waves to cover the distance S from the inlet valve to the collector and back is always the same because they move at the speed of sound, v.
But the time period during which the inlet valve is opened is dependent on engine speed.
As engine speed increases, the period of time during which the inlet valve is open and air can flow into the cylinder decreases.
A high-pressure wave returning through a reso-nance pipe designed for low engine speeds will run into an inlet valve which has already closed. “Ram-effect” charging cannot take place.It is clear that resonance pipes of different lengths are required for optimal charging at every engine speed.
The technical compromise is resonance pipes of different lengths!
Long pipes (torque stage) for low to middle engine speeds. Short pipes (power stage) for high engine speeds.
Resonance pipes of different lengths can be opened or closed depending on engine speed = variable intake manifold.
s = constant (length of resonance pipe)v = constant (speed of sound)
t =
The higher the engine speed, the shorter the resonance pipe length.
“Ram-effect” charging
[ms]
8
The lengths differ for the VR5 and VR6 engines.
The torque pipes follow a tight curve over the cylinder head and terminate in the torque collector.
The power pipes follow a wider curve above the torque pipes and terminate in the second collector, the power collector, which is located over the front part of the torque pipes.
A change-over barrel is inserted in the power pipes, perpendicular to them. It opens the power pipes and, consequently, the power collector as necessary.
A plastic variable intake manifold is planned for all VR engines.
This is more economical than cast aluminium, lighter and offers acoustic advantages.
Resonance pipe lengths (mm)VR5VR6Torque pipes 700770Power pipes
330
450
For assembly reasons, the variable intake mani-fold is divided into an upper and a lower part.The injectors and fuel rail with pressure regulator are integrated into the lower intake manifold part.
The upper intake manifold part contains the resonance pipes, the power collector, the change-over barrel with actuator, the torque collector and the throttle valve positioner, which is attached to the torque collector.
9
Comparison of volumetric efficiency
with variable intake manifold without variable intake manifold
improvement in volumetric efficiency
Torque position of VR6 variable intake manifold
The torque position shows air channelling in low engine speed range.
The change-over barrel has closed the power pipes.
The cylinder draws air through the long torque pipes directly from the torque collector.The effective length of the torque pipes (= resonance pipe length) is 770 mm.The result at low and middle engine speeds is higher volumetric efficiency.
Effective length of torque pipes
212_012
10The variable intake manifold of the VR engines Power position of the VR6 variable intake manifold
The change-over barrel is rotated 90o at a
specified engine speed.
This action opens the power pipes and the con-
nection to the power collector, which results in an
effective length of 450 mm for the power pipes.
Air is now supplied from both the torque pipes
and the power pipes.
The power collector is supplied with air via the
torque and power pipes leading to cylinders
which are not drawing air (see also page 14).
The low-pressure wave created at the start of the
intake process is reflected at the end of the
power pipe in the power collector.
Consequently, it returns after a short period to
the inlet valve as a high-pressure wave.
The shortened length of the resonance pipe
produces a high degree of volumetric efficiency
at a high engine speed.
The power position, designed for the power
range, results in slight differences, as expected.
Change-over to power pipes
at engine speedl
VR5VR6
rpm4200
3950
Comparison of volumetric efficiency
With variable intake manifold
Without variable intake manifold
Improvement in volumetric efficiency
212_014
11
Power and torque of VR6-Motor
with and without variable intake manifold
The gains in power and torque in the low and middle engine speed ranges made with the new variable intake manifold on the VR6 engine are clearly recognisable (the VR5 engine had a variable intake manifold from the start of pro-duction).
The high torque permits a more relaxed driving style in the lower and middle engine speed ranges as well as the frequent use of higher gears without loss of pulling power but with low fuel consumption.
As a result, the change-over barrel is rarely operated.
Impurities such as dust or oil can lodge in the gap between the change-over barrel and its housing, impeding its operation.
To ensure its proper operation, the change-over concept was extended by an additional change-over point in the first stage of development.The change-over barrel is held in the power position up to about 1,100 rpm and only then turned to the torque position.
This additional change-over point causes the change-over barrel to be operated repeatedly, and impurities cannot lodge on it.
212_015
Power with variable intake manifold Power
without variable intake manifold Torque
with variable intake manifold Torque without variable intake manifold Gain in power and torque
M =Torque
P =Power
n =Engine speed (rpm)
12The variable intake manifold of the VR engines
A further development –
the load-dependent change-over
concept
According to this concept, the change-over
points for turning the change-over barrel are
determined according to load.
Below full load, the change-over barrel is
mapped to be in the power position.
This is also the rest position when the engine is
stopped.
To achieve maximum filling of the cylinder, it is
not turned to the torque position until the engine
is close to full load.
Because the resonance pipes are de-tuned, the
resonance-charging effect in the partial load
range is reduced.
For the same planned power, the engine can be
operated with a lower load.
The gas dynamics in the intake manifold are
reduced, consequently reducing the charging
of the combustion chamber.
Patent has been applied for on this
equipment!
Advantages!
Lower fuel consumption
Smoother combustion
Improved acoustics
212_016
13
212_018
The switch mechanism located in the upper intake manifold part works on the change-over barrel principle.
The change-over barrel has a separate passage for each power pipe.
In the power position, the passages become a part of the power pipe.
The change-over barrel is made of plastic and is elastically supported.
Differing expansion coefficients of intake mani-fold and change-over barrel, and security
against seizing place high demands on the relia-bility of the process.
A radial tolerance between the change-over barrel to the power collector is necessary to ensure its operation but must not be too great.Even minimal air gaps lead to a significant reduction in achieved torque. This reduction is caused by the reflected waves travelling bet-ween individual pipes to the power collector, resulting in the loss of energy.
The influence of the air gap of the change-over collector on torque in the VR5 engine.Maximum torque shifts to a higher rpm range.In the power range (open power pipes), the air gap cannot have any significance.
Power airbox and change-over barrel
14The variable intake manifold of the VR engines
Filling the power collector
A reminder:
Closed change-over barrel = torque position
Each cylinder receives its charge of air directly
from the torque collector through its respective
torque pipe.
The power collector is closed for all cylinders.
It has no influence on the volumetric efficiency
of the cylinder.
The power collector is not filled either.
Example of current progression in collector.
At a crankshaft angle of 555o, the current moves from No. 3
cylinder 3 to No. 1 cylinder.
Beginning at about crankshaft angle 605o, the intake phase
of No. 2 cylinder leads to a reversal of the current direction.
Decimal points represented by commas in graphic.
212_003
212_002
Power pipe Open change-over barrel = power position
With its passages (one per pipe) open, the
change-over barrel connects the power pipe to
the power collector.
The cylinder which is drawing at the moment
receives its air primarily from the power pipe but
also through its torque pipe.
In the power position, the power collector is filled
by the flowing volume of air which is reflected
from the closed inlet valves of the cylinders which
are not drawing air.
Air currents develop high velocities in the collec-
tors.
Due to the over-all manifold design, a direct
connection between torque and power collectors
is not necessary for filling the power collector.
212_021
555o CA575o CA
605o CA635o CA
15
3
2415
3
24
cylinder cylinder
15
The tension of the compression spring is over-come and the membrane together with the con-necting rod is pulled downwards.
The change-over barrel is rotated 90 o .The torque position comes into effect.
Intake manifold change-over
Changing pipes is done pneumatically with vacuum.
The pneumatic actuation is controlled by the engine control unit via the intake manifold change-over valve N156 (solenoid valve).The vacuum is taken from the manifold torque collector.
Vacuum is stored in the vacuum reservoir and a check valve prevents the release of the vacuum.The change-over barrel is in the power position, that is, the intake path is short, when the engine is not running or running at idle.
It is held in this position by a compression spring.The intake manifold change-over valve blocks the vacuum to the vacuum unit.
When the intake manifold change-over valve is actuated, vacuum is released to the vacuum unit.
To other consumers
Vacuum unit
16Intake manifold change-over
Intake manifold change-over valve
N156
Function
The intake manifold change-over valve is a sole-
noid valve.
It is controlled by the engine control unit and
depends on load and engine speed.
Atmospheric pressure acts on the magnet which
forms the valve.
Together with the rubber valve plate, it blocks
the vacuum line to the vacuum unit.
When the solenoid is actuated, the magnet is
raised and the vacuum line is opened.
A foamed plastic filter at the entrance for
atmospheric air pressure prevents the penetra-
tion of dirt particles which could impede the
movement of the valve.
Emergency operation
If there is no signal, the vacuum line to the
vacuum unit remains closed. The shorter intake
path in the variable intake manifold remains
open. A substitute function is not planned.
Self-diagnosis
Self-diagnosis is performed with the following
functions:
02-Interrogate fault memory
Short to earth
Short to positive
Open circuit
03-Final control diagnosis
Electrical circuits
J17Fuel pump relay
J220Engine control unit
N156Intake manifold change-over valve
S Fuse
212_001
Atmospheric pressure
17
Service
The variable intake manifold and its actuator are service-free.
If the engine is shown to have power deficits, the operation of the variable intake manifold is easy to test:
–Via self-diagnosis
The intake manifold change-over valve data is available under the functions 02 - Read out fault memory and 03 - Final control diagno-sis.–Visual inspection of the 90o rotation at the vacuum unit with the help of the engine speed.Knowledge of the operation of the variable intake manifold helps as well.
Important:
When the engine is not running or running at idle, the change-over barrel is in position for the shorter intake path, or power position.Bear in mind:
Differing change-over concepts
=with additional change-over point; up to 1100 rpm in power position, then change-over to torque position and at 4200 rpm back to power position.
=load dependent change-over; with throttle burst under full load below 4000 rpm, change-over to torque position.
Checking change-over movement
with vacuum using hand vacuum pump V.A.G 1390.
Please refer to the current workshop manual for exact instructions for all
tests.
212_027
Service.
212
For internal use only? VOLKSWAGEN AG, Wolfsburg
All rights reserved, subject to technical change without notice
740.2810.31.20 technical status 12/98
?This paper was made with chlorine-free
bleached cellulose.
硬质支气管镜的临床应用
首都医科大学附属北京朝阳医院胸外科李辉 写在课前的话 近年来，随着呼吸内镜介入技术的发展，晚期肺癌导致的中央大气道器质性狭窄的病人越来越多，这部分病人需要应用内镜的介入技术来缓解气道狭窄，改善生活质量。因此，硬质气管镜的应用也越来越广泛。此外，麻醉技术的改善以及硬镜相关辅助机械通气水平的提高，使硬质气管镜的临床应用更为简便和安全。通过本课件的学习，学员将能了解硬质支气管镜的发展史，明确其适应证与禁忌证，并掌握其操作方法。 硬质支气管镜的临床应用已经有100多年的历史，它在呼吸系统疾病的诊断和治疗中发挥过非常重要的作用。但是近40年来，随着可弯曲纤维支气管镜在临床的广泛应用，硬质支气管镜的应用越来越少，大约只有4%～8%的临床医生在工作中使用硬质支气管镜。 一、硬质支气管镜的发展史 公元前400年，Hippocrates建议将一根管子插入喉部以救治窒息患者，成为气道内介入的最早雏形。18世纪中叶，Desault提出经鼻气管内插管缓解窒息并取出异物。1895年，德国医生Alfred Kirstein利用一条橡皮胶管和一个灯泡检查喉的下部，并应用一个管状的压舌板作为直接喉镜观察病人。Kirstein的学生Gustaf Killian医生在此基础上结合了19世纪末的三大发明，即麻醉、可用性光源、上消化道内镜和喉镜，在历史上首次应用内镜技术来处理呼吸道病变。1897年3月30日，Gustaf Killian医生为一个63 岁的患者取出因误
吸入气管的猪骨，并于1898年在德国海德堡的一个医学会议上报道了用同样的方法成功处理了3例气道异物。Killian医生一生致力于气道内镜结构的改善和操作技术的提高，并提出了气管、支气管树图谱，在历史上确立了“气道内镜之父”的地位。 另一个对气道内镜的发展作出巨大贡献的是美国医生Chevaliar Jackson。他构建了美国第一台气道内镜，并配备了载光和吸引系统。1907年，他首次出版了专著《气管镜，食管镜，支气管镜》一书。1930年Jackson医生和他的儿子在Temple大学建立了首家内镜诊所，培养了大批内镜专业的杰出人才。其中一位是Johns Hopkins大学医学院内镜科主任，Broyles医生，他发明了有远端光源的观察目镜和纤维光源，使气道内镜具有前视和侧视功能，以观察上、下叶支气管及分支。Jackson的另一位学生，Temple大学的Holinger医生发明了内镜照相，为资料的处理储存和教学提供了条件，对内镜技术的发展和经验积累发挥了积极作用。此后，英国Redding大学的内科医生Hopkins发明了圆形镜面的观察目镜系统，大大改善了硬镜的照明和影像质量。 二、技术线路和原理 现代硬镜为一空心不锈钢管，管径均一，在其远端1/3镜体的管壁上带 有侧孔，请问这样可起到什么样的作用？ （一）设备 现代硬镜为一空心不锈钢管，管径均一，管壁厚2mm。成人硬镜直径9mm，长度40cm，远端是斜面，以便通过声门和气道狭窄区域，同时也利于铲切除去气道壁上的肿瘤，远端1/3镜体的管壁上带有侧孔，便于镜体进入一侧主支气管时对侧气道保持通气。
马自达6发动机进气系统可变进气歧管工作原理
马自达6轿车在进气系统上为了保证最大的进气量，共有五大先进装备，称之为“VAD+VIS +VTCS+ETC+S-VT”，这是马自达6轿车独有的先进技术。 （一）VAD-Variable Air Duct可变进气道 功能：可在PCM的控制下，在发动机大功率输出时适时打开VAD气道（多打开一个气道，相当于气道口径变大），可以最大程度地保证发动机空气量的需求充分发挥发动机的动力性能。 （二）VIS- Variable Intake-air System可变进气歧管 功能：在PCM的控制下，在小负荷低转速到大负荷高转速范围内都保持高的扭矩。 工作原理：改变有效进气歧管的长度，有效控制进气气流在进气道中的流动惯性，使气流的流动压力波的频率和进气门的频率在不同工况下适时吻合，进而最大程度保证发动机在任何工况的进气量。实质是利用的中惯性谐波增压的原理来实现发动机的最大进气量。当发动机转速低于4400转时，VIS不起作用，VIS阀门是关闭的，气流的路径较长；当发动机转速大于4400转时，VIS起作用，VIS阀门是打开的，气流的路径是较短；这样满足不同工况的空气量的需求。 （三）VTCS- Variable Tumble Control System可变涡流控制 功能：在不同的水温和转速下将进气歧管的开度打开不同的开度，以满足发动机各个工况空气的需求。 原理：在同一工况下，不同的VTCS阀门开度，使得进入发动机的气流流速发生改变，形成涡旋，涡流即是我们常说的旋涡，使得发动机的油气混合达更加充分。特别是发动机在低温冷起动 和发动机处于低负荷时，混合气的雾化不好，燃烧不充分，排放不良，为了改善低温时汽油的雾化水平，提高发动机的排放水平，使马自达6的排放水平达到和超过欧Ⅲ标准。工作过程：当水温低于62度左右，并且发动机的转速低于3750转时，使进气管的通道面积减小；随着水温的进一步提高，转速进一步上升，VTCS阀的开度完全打开，进气管的面积达到最大。 （四）ETC-Electronic Controi Throttle Valve电子节气门 顾名思义它不是由油门拉线控制进气总管的开度而是利用直流电机通过减速机构来自动实现的。 功能和工作过程：它具有普通节气门的基本功能，其作用是打开进气歧管在总管上的通道，不同工况打开不同的开度，一般轿车的节气门都是由脚踏板带动的油门拉线控制。但这种拉线控制的节气门在急加速等特殊工况时有进气迟滞现象，也就是说在急加速等特殊工况时，节气门的开度信号通过节所气门位置传感器已送出，但实际进入气缸的空气并没有及时跟进，而且节气门处在气流扰动下并不是很平稳，因此空气量并不稳定，加速不理想和不稳定。而电子节气门可根据节气门位置信号，PCM直接驱动直流电动机快速作响应，及时地将节气门打开所需的开度，而且电子节气门在自身减速机构的自锁作用下，不会因为气流的
可变进气歧管在发动机中的应用
可变进气歧管 技术在汽车发动机中的应用 V ariable intake manifold technology applications in the automotive engine
摘要 进气系统最重要的部分就是进气歧管，它就是一支引导气流的管子，空气经过滤清器之后，在此进行油气混合，并输送到汽缸进行燃烧。由于混合气是具有质量的流体，在进气管中的流动千变万化，工程上往往要运用流体力学来优化进气管的内部设计，例如将进气歧管内壁打磨光滑减少阻力，或者刻意制造粗糙面营造汽缸内的涡流运动。但是，正如前面所说，汽车发动机的工作转速高达每分钟数千转，各工作状态下的进气需求不尽相同。于是，天才的工程师们对进气歧管进行了深层次的开发——让它也能“变”起来。 关键词：进气系统进气歧管汽车发动机
Abstract The most important part of the intake system is the intake manifold, it is a guide tube flow of air through the filter, the oil and gas in this mixture, and transported to the cylinder for combustion. As the mixture is a mass of fluid flow in the intake manifold of the ever-changing, often on a project to optimize the use of fluid into the pipe interior design, such as intake manifold wall polished smooth to reduce resistance, or deliberately created to create a rough surface vortex motion within the cylinder. But, as I said before, the car engine working speed of up to several thousand per minute switch, the working conditions of the intake needs vary. Thus, the genius of the engineers on the intake manifold for the development of deep level - it can "change" them. Keywords: Intake Air intake manifold Automotive engine
可变长度进气管原理
M [N m ] P [k W ] n [min ] -1P =n ? M 9550 [kW] Variable Intake Manifold in VR Engines Principles and Description of Operation Self-study programme 212 Service.
2 NEW This self-study programme explains how it was possible to optimise the torque and output of the VR engine with the concept and design of the new intake manifold and just how an intake tract affects the air supply. The VR6 engine, in which the conventional intake manifold has been replaced by the new variable intake manifold, provides an example which makes the increase in power and torque very clear. A patent for the variable intake manifold concept of the VR engine has been applied for. The output and torque of an engine have the greatest effect on the engine’s character.These, in turn, are greatly affected by the degree to which the cylinder is filled and the geometric form of the intake tract. High torque requires an intake manifold with a geometry different to one for high power output.A medium intake manifold length with a medium diameter represents a compromise, but a variable intake manifold is optimal. 212_020
支气管镜指南
诊断性可弯曲支气管镜应用指南 发表时间：2008-12-16发表者：(访问人次：506) 可弯曲支气管镜(包括纤维支气管镜、电子支气管镜；以下简称支气管镜)检查是呼吸系统疾病临床诊断和治疗的重要手段，并已在临床广泛应用。《诊断性可弯曲支气管镜应用指南(2008年版)》(以下简称指南)在中华医学会呼吸病学分会2000年公布的《纤维支气管镜(可弯曲支气管镜)临床应用指南(草案)》的基础上进行了修订及增补。本指南在增加了支气管镜清洗和消毒及医务人员防护等内容的基础上，综合国内外的相关文献，按照循证医学的原则对相关内容进行了分级(表1)，目的是进一步规范支气管镜检查的操作，提高的检出率，减少相关不良事件及并发症的发生。鉴于支气管镜下的治疗领域涉及范围广，技术要求相对复杂，故本指南未涉及相关内容。 一、支气管镜检查的适应证及禁忌证 (一)适应证 1．不明原因的慢性。支气管镜对于诊断支气管结核、异物吸人及气道良、恶性等具有重要价值。 2．不明原因的咯血或痰中带血。尤其是40岁以上的患者，持续1周以上的咯血或痰中带血。支气管镜检查有助于明确出血部位 和出血原因。 3．不明原因的局限性哮鸣音。支气管镜有助于查明气道阻塞的 原因、部位及性质。
4．不明原因的声音嘶哑。可能因喉返神经受累引起的声带麻痹 和气道内新生物等所致。 5．痰中发现癌细胞或可疑癌细胞。 6．X线胸片和(或)CT检查提示肺不张、肺部结节或块影、阻塞性、炎症不吸收、肺部弥漫变、肺门和(或)纵隔淋巴结肿大、气管支气管狭窄以及原因未明的等异常改变者。 7．肺部手术前检查，对指导手术切除部位、范围及估计预后有 参考价值。 8．胸部外伤、怀疑有气管支气管裂伤或断裂，支气管镜检查常 可明确诊断。 9．肺或支气管性疾病(包括免疫抑制患者支气管肺部感染)的病因学诊断，如通过气管吸引、保护性标本刷或支气管肺泡灌洗(B AL)获取标本进行培养等。 10．机械通气时的气道管理。 11．疑有气管、支气管瘘的确诊。 (二)禁忌证 支气管镜检查开展至今，已积累了丰富的经验，其禁忌证范围亦日趋缩小，或仅属于相对禁忌。但在下列情况下行支气管镜检查发生并发症的风险显着高于一般人群，应慎重权衡利弊后再决定 是否进行检查。 1．活动性大咯血。若必须要行支气管镜检查时，应在建立人工气道后进行，以降低窒息发生的风险。
别克凯越可变进气歧管故障诊断与排除
别克凯越可变进气歧管故障诊断与排除 摘要：08款别克凯越轿车，行驶52000公里出现仪表盘内故障灯亮，通过诊断，发现是可变进气歧管电磁阀控制电路故障，通过了解可变进气歧管的工作原理，诊断与排除可变进气歧管故障。 关键词：凯越;可变进气歧管;电磁阀 1.故障现象 一辆2008款别克凯越轿车来店维修，行驶里程为52000公里。根据车主反应，车辆在行驶过程中发现仪表盘内发动机故障灯点亮。通过使用KT600诊断，读出两个故障码，分别是P1109和P0443。记录以后进行消码处理，重新着车并试运行一段距离以后，重新读取故障，发现只剩下P1109。经过查验维修手册，P1109是可变进气歧管电磁阀控制电路。 该车发动机装备发动机F16D3直列4缸、双顶置凸轮轴，采用多点式喷射和自然进气。为增加发动机动力输出采用可变进气歧管装置。 2.可变进气歧管工作原理 为了确定故障原因是否是由可变进气歧管电磁阀控制电路造成的，首先需要了解可变进气歧管工作原理： 可变进气岐管（VGIS）控制阀系统采用可变进气技术使发动机在不同运转速率下达到工作性能和效率的最大化。发动机的扭矩输出曲线特性主要取决于一定速率下的平均压力变化。当进气阀门闭合时，缸内平均压力的变化和进气量成一定的比例。 当发动机速率一定时，进气量的大小则与进气阀门系统的设计有关。VGIS 控制阀常用来改善进气岐管的腔体结构。当VGIS控制阀断开时，进气岐管内形成一个较大的腔体。当VGIS控制阀闭合时，进气岐管内形成两个较小的腔体。两种腔体尺寸导致了不同的扭矩曲线，以此来改善发动机处于低速或高速时的工作性能。 在低速、高负载情况下，VGIS控制阀闭合，此时腔体内形成一个较长的进气通道，以此增加扭矩。在高速、高负载情况下，VGIS控制阀断开，此时腔体内形成一个较短的进气通道，以此增加马力。 当点火开关点着时，在保险丝保护下，点火电压向VGIS控制阀线圈供电。VGIS控制阀线圈常闭时空气无法通过阀体。当发动机的速度和负载增加至设定的阈值时，VGIS控制阀线圈通过发动机控制模块（ECM）接地，同时被触发，并通过控制阀执行器向控制阀的气腔进气。随后，执行器将进气岐管打开至预期
超声支气管镜系统
超声支气管镜系统 设备主要原理、技术参数及配置要求： 重要技术参数： 1、适用于呼吸道、肺及周边脏器超声的检查和治疗 2、含超声、内镜系统，须国际著名品牌。 3、内镜系统、超声支气管镜系统都是同品牌，(后续能兼容同品 牌超声小探头系统可加分) 4、厂家质保，河南拥有售后服务点。 一般技术参数： 1摄像系统部分 1.1图像处理装置 1.1.1 高清信号输出，分辨率1080； 1.1.2 自动白平衡调节功能； 1.1.3 构造强调、轮廓强调功能 1.1.4 测光模式 1.1.5 具备IEE特殊光功能； 1.1.6 色彩调节； 1.1.7 电子放大功能2倍； 1.1.9 双动态画面模式
1.1.8 图片存储功能 1.1.8 外接存储设备 1.1.8 DICOM数据接口 1.2内窥镜冷光源 1.2.1 300W氙灯 1.2.2 具备应急灯 1.3显示器 1.3.1尺寸≥24英寸 1.3.2分辨率:1920×1080(全HD) 1.4进口台车 2超声内镜部分 2.1.超声主机 2.1.1电子扫描模式，支持环扫和扇扫 2.1.2扫描显示：环形：全圆、上半圆、下半圆、滚动显示 2.1.3高清输出：DVI（数字）、 HD-SDI*2 2.1.4图像方向：正像/倒转 2.1.5显示模式：B模式，彩色多普勒，能量模式、组织谐波 THI模式 2.1.6可用频率：5 MHz-12 MHz 2.1.7画中画：内镜/超声图像切换 2.1.8 显示深度：15-120mm 2.1.8测量面积/周长
2.1.9具备弹性成像功能 2.1.10具备脉冲多普勒功能 2.1.11复合谐波CH模式、造影谐波CHI模式 2.1.12预设焦点：2个 2.2 超声支气管镜参数
可变进气歧管设计探讨
可变进气歧管设计探讨 作者：孙宗强来源：AI汽车制造业 为了充分利用轿车汽油机进气歧管的谐波效应和尽量缩小轿车汽油机在高、低速运转及大、中、小各种负荷运转时进气速度的差别，现代轿车汽油机采用了可变进气系统。它由可变进气歧管（VIM）和可变气门正时（VVT）等结构组成。采用可变进气歧管技术后，现代轿车汽油机可以实现：每一气缸使用第一和第二两个进气歧管，即两个进气气流通道。通过改变第二进气歧管上控制阀开度，可使轿车汽油机总的进气歧管长度和截面面积发生变化，从而改善轿车汽油机在中、低速和中、小负荷的动力性、燃油经济性及排放净化性。 正常行驶的轿车要求搭载的汽油机在高转速、大负荷时，进气已具有较高的流速，相应的进气阻力有增大的倾向。为了减少进气流动阻力，需要用短而粗的进气歧管；在中、低转速和中小负荷时进气气流速度较小，进气压力较小，配用进气截面较小（细）、歧管长度较长的进气歧管。 设计原则及设计要点 设计原则要求各缸进气量要多而且要均匀。为了实现轿车多缸汽油机进气均匀分配，总的设计要点是： 1.力求对所有气缸具有相同气流通道（包括管长、截面尺寸、对称性都要求一致）； 2.力求具有很高的紊流强度； 3.力求具有合适的（进气予热）加热区域； 4.力求具有光滑的内表面（这对减小油膜厚度有利）；例如复合塑料进气歧管的内表面。 5.力求选用合适的气流速度； 6.可变进气歧管安装位置、外形尺寸要符合要求。 典型结构及简要分析 1.可变长度进气歧管结构 图1 可变长度进气歧管 图1为一种能根据轿车汽油机转速和负荷的变化而自动改变有效长度的进气歧管。
当汽油机低速运转时，汽油机电子控制模块指令转换阀控制机构关闭转换阀。这时，空气须经空气滤清器和节气门沿着弯曲而又细长的进气歧管流进气缸。细长的进气歧管提高了进气速度，增强了气流的惯性，使进气充量增多；当汽油机高速运转时，汽油机电子控制模块指令转换阀控制机构，打开转换阀，空气经空气滤清器和节气门及转换阀直接进入粗短的进气歧管。粗短的进气歧管，进气阻力减小，也使进气充量增多。 可变长度进气歧管不仅可以提高汽油机在中、低速和中、小负荷时的动力性，即提高有效输出扭矩Mem；还由于它提高了汽油机在中、低速运转时的进气速度W，而增强了气缸内的气流强度，从而改善了燃烧过程，使汽油机中、低速的最低燃油消耗率ge下降，燃油经济性有所提高。 此外，可变长度进气歧管还有减少汽油机废气排放量的作用。因为汽油机燃烧过程改善后，不仅油耗降低，经济性改善，汽油机的有害排气污染物的排放量也能适当减少，即轿车汽油机的排放净化性能也可适当改善。 2.双通道可变进气歧管 图2 双通道可变进气歧管 双通道可变进气歧管的结构见图2。 每个进气歧管都有两个进气通道，一长一短。根据汽油机的工作转速高低、负荷大小，由旋转阀2控制空气经过哪一个通道流进气缸。在长进气道中安装有喷油器。当汽油机在中、低速运转时，旋转阀2受到由汽油机电子控制模块发出的指令，在旋转阀控制机构（执行器）作用下，将短进气通道1封闭，新鲜空气充量经空气滤清器、节气门沿长进气通道3经过缸盖上的进气道5和进气门6进入气缸；当汽油机在高速运转时，汽油机电子控制模块发出指令，旋转阀控制机构（执行器）作用将短进气道1打开，使长进气道通道短路，将长进气通道改变为辅