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Vacuum elevators use a sealed lift tube and the clever manipulation of air pressure to raise and lower the lift. Each ascent uses only a minimal amount of electricity, and descending requires almost no energy at all. It’s all controlled by gravity and air – no heavy machinery required.
PERFOMANCE BOOST The Freescale* MPXV4115V pressure sensor is the ideal part for automotive vacuum sensing needs such as those found in the brake booster application. Prepared by Marc Osajda Automotive Sensor Marketing Motorola – Toulouse, France Advanced braking systems are becoming increasingly common in today’s automobiles. Higher level systems and technology now being used in “brake assist systems” (BAS) in several European cars, have made it possible for more efficient and intelligent braking systems. A key functional application block found in these braking systems that has advanced with this technology surge, is the vacuum brake booster function. Here are a few driving factors behind the need and use of the brake booster, which helps ensure a safer braking system. Independent Systems: In current gasoline engine cars, the engine’s intake manifold generates the vacuum for the brake booster. This system works fine with one exception. The amount of vacuum in the brake booster is unknown by the braking system. Thus the amount of amplification is also unknown. If heavy braking is needed, there is no possibility for the brake system to interact with the intake manifold if additional amplification is required. The manufacturer’s interest for having the vacuum generated by an auxiliary vacuum pump is that the brake system can manage the amount of vacuum as required, on demand. This in turns gives it the ability to perform amplification on its own, giving it complete independent from the engine’s operating condition. The auxiliary pump is also able to provide higher amounts of vacuum whenever necessary. In situations calling for heavy braking, the pressure will naturally decrease in the brake booster, also causing a decrease in the amplification during braking. With an external pump it is possible to maintain, or even increase the amplification during a heavy braking phase. Smart Safety: Wheel blocking due to high-braking force is controlled by the Anti-Lock Brake System (ABS). However, it has been observed that in many cases, drivers do not...
930394-52 Rev. 12/22/05 4:21 PM Page 1 HYDRO-BOOST BRAKE BOOSTER Installation Guide 4. Enable ignition system and start the engine. 7. Check fluid level and add fluid if needed. 5. Turn the steering wheel from stop to stop several times. Do not hold it against the stop. 8. Again start engine and turn steering wheel from stop to stop several times (avoid turning fully against stops as much as possible). Recheck fluid level and fill as required. If there is evidence of fluid foaming, turn off engine and wait an hour for foam to clear. Lacks Power Assist Booster or Pedal Chatters X X X Looses Reserve Pressure HAIRPIN CLIP BRAKE PEDAL PUSHROD X PUSHROD SPACER PUSHROD BUSHING 6. Loosen the locknuts holding the HydroBoost unit to the firewall and then slide the linkage, nylon washers and brushing off the pedal pin. 4. Disconnect all hydraulic lines from the Hydro-Boost unit (pressure, steering gear and return lines). PRESSURE LINE MASTER CYLINDER HYDRO-BOOST SPACER X X X BRAKE LINES DO NOT DISCONNECT JDA356 STOP-LIGHT SWITCH 3. Separate the master cylinder from the mounting studs. N OT E : DO NOT disconnect the brake lines from the master cylinder unless necessary to avoid bending or damaging those lines. X Pedal Returns Slowly 5. Disconnect the Hydro-Boost pushrod linkage from the brake pedal. NOT E : It may be necessary to remove the stoplight switch from the brake pedal. If so, unplug the stoplight switch wires, remove the hairpin retainer, slide the switch off the pedal pin just far enough to permit removing the switch from the pin. Do not damage the switch. N OT E : Before beginning work, be sure vehicle is parked in a level area and that wheels are chocked to prevent unintentional movement. Read all of these instructions before attempting to install the HydroBoost unit. 2. Remove the nuts attaching the master cylinder to the Hydro-Boost unit.
Fifty percent less pedal force I n most of the models of the 1950s and 1960s, Mercedes-Benz provided a power brake booster manufactured by ATE. The booster does not pro- vide additional braking capacity, a common misconception, but rather reduces the pedal force required for braking. The power brake is a vacuum-assisted hydraulic component using the pressure difference between engine intake manifold vacuum and atmospheric pressure for its operation. The power unit increases the pressure created physically in the brake master cylinder so that the same braking effect can be produced with less pedal effort. With a brake booster installed, the pedal force required for braking is reduced by 50 percent. The ATE T50 Brake Booster uses vacuum to “boost” the hydraulic brakeline pressure. The booster contains a hydraulic cylinder, a large vacuum piston that presses against the hydraulic cylinder, and a control circuit that regulates the vacuum flow based on brake-line pressures. This technology had been well proven since the early 1900s, and the T50 has been exceptionally reliable over many years of use. The Booster in action The power booster is a very simple design requiring only a vacuum source to operate. In gasoline-engine cars, the engine provides a vacuum suitable for the boosters. Because diesel engines do not produce a vacuum, dieselpowered vehicles must use a separate vacuum pump. A vacuum hose from the intake manifold on the engine pulls air from both sides of the diaphragm when the engine is running. When the driver steps on the brake pedal, the input rod assembly in the booster moves forward, blocking off the vacuum port to the backside of the diaphragm and opening an atmospheric port that allows air to enter the back chamber. Suddenly, the diaphragm has vacuum pulling against one side and air pressure pushing on the other. The result is forward pressure that assists in pushing the input rod, which in turn pushes the piston in the master cylinder. The amount of power assist that’s provided by the booster depends on the size of the diaphragm and the amount of intake manifold vacuum produced by the engine. A larger diaphragm will increase the boost.
Introduction Everybody knows that when you press your foot on the brake pedal the vehicle is supposed to stop. But how does the pressure from your foot get to the wheels with enough force to stop a heavy vehicle? In the following sections, we will study the systems and components required to allow brakes to work effectively. Course Objectives Upon completion of this course, technicians should understand and be able to apply their knowledge of: • • • • • • • • • • • • Brake functions and components Split hydraulic systems Master cylinder operations Balance control systems Power brake booster systems Disc brake operation Micrometer reading Drum brake operation Brake fluids Brake bleeding operations Brake lines and hoses Basic diagnosis Using the Job Sheets As you proceed through the online module, on some pages you will find links that will open a window with a printable procedure or job sheet containing hands-on lab activities based on the NATEF standards related to the content you are studying. When you come upon a procedure or job sheet link, click on it and print the job sheet for completion in the shop. See your instructor for guidance in completing the job sheets. Some jobs sheets will require supplemental materials such as a vehicle service manual, equipment manual, or other references. Brake System Functions Automotive brakes are designed to slow and stop a vehicle by transforming kinetic (motion) energy into heat energy. As the brake linings contact the drums/rotors they create friction which produces the heat energy. The intensity of the heat is proportional to the vehicle speed, the weight of the vehicle, and the quickness of the stop. Faster speeds, heavier vehicles, and quicker stops equal more heat. Automotive brake systems can be broken down into several different sub-systems (fig. 1): • Apply system • Boost system • Hydraulic system • Wheel brakes • Balance control system • Warning system (fig. 1) Base Brake Systems .
The clutch master cylinder is a device that transforms mechanical force into hydraulic pressure. As the driver presses the clutch pedal, the pedal lever applies force to the clutch master cylinder which transmits hydraulic pressure to the clutch release (slave) cylinder that disconnects engine power to the transmission. Structure and Components [Conventional Type] Inlet Union Oil Spill Hole Aluminum Body Flare Nut Pipe Joint Boot Spring Primary Cup Resin Piston Push Rod Rel Secondary Cup Spring Metallic Clevis Damper Stud Bolt The clutch master cylinder structure consists of the piston, cups, and springs, built within a precision machined body. The primary cup, positioned on the leading side of the body, functions to create hydraulic pressure when fluid is forced inside by the piston. Located on the trailing side is the secondary cup, which guides the piston and prevents fluid from leaking. When the clutch pedal is pressed, the primary cup is blocked away by the piston from the oil spill port leading to the reservoir tank, pressure in the cylinder rises as the fluid is fed through the pipeline. When the clutch pedal is released, the hydraulic pressure and the force of the return spring pulls back the piston to relieve fluid back into the reservoir. The clutch master cylinder is what provides the necessary force to control the application of drivetrain power. 2 Clutch Master Cylinder Variations Clutch Master Cylinder Variations Conventional Port-less Type Stand Alone / Integrated Reservoir Type Types With and Without Stud Bolts Types With and Without Clevis Damper Types With and Without Clutch Booster ...
GENERAL PROCEDURES Driveshaft Runout and Balancing Special Tool(s) Dial Indicator Gauge with Holding Fixture 100-002 (TOOL-4201-C) or equivalent Mastertech® Series MTS 4000 Driveline Balance and NVH Analyzer (Vetronix) 257-00018 or equivalent Driveshaft Inspection NOTE: Driveline vibration exhibits a higher frequency and lower amplitude than high-speed shake. Driveline vibration is directly related to the speed of the vehicle and is noticed at various speeds. Driveline vibration can be perceived as a tremor in the floorpan or heard as a rumble, hum or boom. NOTE: Refer to Specifications in this section for all runout specifications. 1. NOTE: Do not make any adjustments before carrying out a road test. Do not change the tire pressure or the vehicle load. Carry out a visual inspection of the vehicle. Operate the vehicle and verify the condition by reproducing it during the road test. • 2. With the vehicle in NEUTRAL, position it on a hoist. For additional information, refer to Section 100-02. • 3. The concern should be directly related to vehicle road speed, not affected by acceleration or deceleration or could not be reduced by coasting in NEUTRAL. The driveshaft should be kept at an angle equal to or close to the curb-weighted position. Use a twin-post hoist or a frame hoist with jackstands. Inspect the driveshaft for damage, undercoating or incorrectly seated U-joints. Rotate the driveshaft slowly by hand and feel for binding or end play in the U-joint trunnions. Remove the driveshaft. For additional information, refer to Section 205-01. Inspect the slip yoke splines for any galling, dirt, rust or incorrect lubrication. Clean the driveshaft or install new U-joints as necessary. Install a new driveshaft if damaged. After any corrections or new components are installed, recheck for the vibration at the road test speed.
Henan Li Marine Technology Submission date: June 2012 Supervisor: Svein Sævik, IMT Norwegian University of Science and Technology Department of Marine Technology THESIS WORK SPRING 2012 for Stud. tech. Henan Li Flexible Pipe Stress and Fatigue Analysis Spennings- og utmatnings-analyse av fleksible stigerø r The flexible riser represents a vital part of many oil and gas production systems. During operation of such risers, several failure incidents may take place e.g. caused by fatigue and corrosion. In limit cases where inspections indicate damage, the decision making with regard to continue operation or replacing the riser may have large economic and environmental consequences. Hence, the decision must be based on accurate models to predict the residual strength of the pipe. In most applications, one or several steel layers are used to carry the hoop stress resulting from internal pressure. This is further combined with two layers of cross-wound armour tendons (typically 40-60 tendons in one layer installed with an angle of 35o with the pipe’s length axis) acting as the steel tensile armour to resist the tension and end cap wall force resulting from pressure. The riser fatigue performance may in many cases be governed by the dynamic stresses in the tensile armour. The existing lifetime models for such structures is primarily based on inherent assumptions with respect to the slip properties of the tensile armour. This thesis work focus on establishing a FEM based model for analysis of the tensile armour, so as to analyse the stress and slip behaviour when exposed to different load conditions. The thesis work is to be based on the project work performed and shall include the following steps: 1) Literature study, including flexible pipe technology, failure modes and design criteria, analytical methods for stress analysis of flexible pipes,...
DESCRIPTION OF A COFLEXIP® FLEXIBLE LINE The Coflexip® Flexible Line Coflexip® products are designed for oilfield services, both on and offshore, where heavy duty is required in combination with Flexible lines are manufactured in long continuous sections (up to several kilometres) and are cut to fit each client's requirements. End fittings with the most common types of end connectors are kept in stock thus minimising delivery times. End connectors not kept in stock will be machined or obtained according to the client's specifications. Delivery time depends mainly on the type of end connectors required and our client’s particular specifications. The pipe structure Coflexip® pipes are composed of successive layers of steel and thermoplastic to produce unique structures that have the strength and durability of steel pipes combined with the flexibility of reinforced rubber hoses. Each layer works independently from the others, as no vulcanisation is used during manufacturing. This results in the structural stability of the pipe. flexibility and Functions of Coflexip® pipe components reliability. These requirements are in applications such as: Choke and kill lines Rotary and vibrator lines Test lines Hydraulic lines Acid and cement lines Nitrogen lines Coflexip® flexible pipes for drilling and service applications are manufactured by the Drilling & Refining Applications Division of the Technip Group 2 1. The thermoplastic inner tube makes the pipe leak-tight. 2. The interlocked zeta and flat steel spiral pressure carcass resist internal pressure and external crushing loads. 3. The intermediate thermoplastic sheath is an anti-friction layer. 4. The double crosswound steel armours resist axial loads, protect the pipe from torsional strain resulting from handling and working conditions. 5. The thermoplastic outer jacket protects the armours from external corrosion. 6. The Stainless Steel Outer Wrap (SSOW), protects the pipe from mechanical impact, abrasion, weathering and accidental mishandling.
When a ﬂow is driven through a deformable channel or tube, interactions between ﬂuid-mechanical and elastic forces can lead to a variety of biologically signiﬁcant phenomena, including nonlinear pressure-drop/ﬂow-rate relations, wave propagation, and the generation of instabilities. Understanding the physical origin and nature of these phenomena remains a signiﬁcant experimental, analytical, and computational challenge, involving unsteady ﬂows at low or high Reynolds numbers, large-amplitude ﬂuid-structure interactions, free-surface ﬂows, and intrinsically 2D or 3D motion. Whereas frequently the internal ﬂow involves a single ﬂuid phase (albeit often of a complex biological ﬂuid such as blood), in many instances the presence of two or more distinct ﬂowing phases is of primary importance (as is the case for air-liquid ﬂows in peripheral lung airways, for example). We divide this review accordingly: Section 2 treats single-phase ﬂows in collapsible tubes, Section 3 covers recent applications of such ﬂows to a wide range of physiological 0066-4189/04/0115-0121$14.00