• Insert the necessary special words and auxiliary verbs to form the following special questions:

1. … … some carmakers begin to use diagonally split systems?

2. … happens when hydraulic force applies pressure through the wheel cylinders and calipers?

3. .... all of today's cars … required to use some type of hydraulically split system?

• Translate from English into Russian without the dictionary:

1. Most brake systems multiply the force in the process.

2. Force applied at one point is transmitted to another point using an incompressible fluid.

3. The pedal is designed in such a way that it can multiply the force from your leg several times before any force is even transmitted to the brake fluid.

4. Changing the relative lengths of the left and right ends of the lever changes the multipliers.

5. If you apply a downward force to one piston, then the force is transmitted to the second piston through the oil in the pipe.

6. The great thing about hydraulic systems is that the pipe connecting the two cylinders can be any length and shape, allowing it to snake through all sorts of things separating the two pistons.

7. The pipe can also fork, so that one master cylinder can drive more than one slave cylinder if desired.

8. Since oil is incompressible, the efficiency is very good – almost all of the applied force appears at the second piston.

9. In a hydraulic system, all you have to do is change the size of one piston and cylinder relative to the other.

(with the help of http://auto.howstuffworks.com/brake1.htm)

• Insert the terms into the text using your active vocabulary. Have you found anything new about the hydraulic brake system?

The hydraulic … system consists of the master …, disc … calipers (disc brakes), … cylinders (drum brakes), … lines and hoses, and combination/proportioning valve. When you push on the brake …, the force of your leg generates hydraulic … in the master cylinder, which then flows through the hydraulic lines and … to the wheel cylinders and calipers. The … force applies pressure through the wheel cylinders and calipers, forcing the shoes against the … (drum brakes) and the pads against the rotors (disc brakes). In the early 1960's, cars began using split … systems and tandem … cylinders. Essentially, this divided the hydraulic system into two separate systems (front and back), ensuring proper hydraulic and braking on one side of the system, if a leak developed on the other side. In the 1980's, some carmakers began to use diagonally split systems, which took safety a step further. Instead of splitting the system into front and …, the system was now hydraulically divided into left-rear/right-front and right-rear/left-front. By maintaining one front and one rear …, the result is more balanced braking when the system develops a leak. By law, all of today's cars are required to use some type of hydraulically split system.

The hydraulic system transmits and multiples force as needed to provide braking action throughout the brake system.

(from http://www.carcare.org/Brakes/hydraulics.shtml)

• Imagine that you are a hydraulics specialist who was asked to explain the hydraulic multiplication. Read the text quickly and then translate it remembering about the special intonation. Then give a brief explanation of the hydraulic multiplication without the help of the text.

To determine the multiplication factor in the figure above, start by looking at the size of the pistons. Assume that the piston on the left is 2 inches (5.08 cm) in diameter (1-inch / 2.54 cm radius), while the piston on the right is 6 inches (15.24 cm) in diameter (3-inch / 7.62 cm radius). The area of the two pistons is Pi * r2. The area of the left piston is therefore 3.14, while the area of the piston on the right is 28.26. The piston on the right is nine times larger than the piston on the left. This means that any force applied to the left-hand piston will come out nine times greater on the right-hand piston. So, if you apply a 100-pound downward force to the left piston, a 900-pound upward force will appear on the right. The only catch is that you will have to depress the left piston 9 inches (22.86 cm) to raise the right piston 1 inch (2.54 cm).

(from http://auto.howstuffworks.com/brake1.htm)

Unit 2

Text Types of Hydraulic Fluids

• Can you explain what a hydraulic fluid is? What is its main purpose?

• Read the definition and the brief explanation of «hydraulic fluid» and compare this information with your personal knowledge.

Hydraulic fluids are a large group of fluids used as the motive medium in hydraulic machinery. Fluid types include synthetic compounds, mineral oil, water, and water-based mixtures. The fluids are found in machinery and equipment ranging from brakes, power steering systems, and transmissions to backhoes, excavators, garbage trucks and industrial shredders. Hydraulic systems are very common in aircraft flight control systems. They will work most efficiently if the hydraulic fluid used has low compressibility.

(from http://en.wikipedia.org/wiki/Hydraulic_fluid)

motive medium движущий, приводящий в движение

steering system система рулевого управления

backhoe канавокопатель с обратной лопатой

shredder комбинированная установка для дробления

marine морской

to dredge копать с помощью землечерпалки

compressibility сжимаемость, прессуемость

• Translate the following names of the hydraulic fluid components from English into Russian and pay special attention to the pronunciation while reading aloud:

castor oil, glycol, esters, ethers, mineral oil, organophosphate ester, polyalphaolefin, propylene glycol, or silicone. oils, butanol, esters, phthalates, adipates, bis(2-ethylhexyl) adipate), polyalkylene glycols (PAG), phosphate esters, tributylphosphate, silicones, alkylated aromatic hydrocarbons, polyalphaolefins, polyisobutenes.

Words and phrases:

shipboard systems системы на борту корабля

additive присадка; добавка

foam пена

viscosity вязкость, коэффициент вязкости

electrohydraulic steering электрогидравлический рулевой привод

deckmachinery systems системы палубных механизмов

shock absorber амортизатор

seal materials герметизирующий материал

compatible with быть совмещаемым, подходить

desired желаемый

flammable огнеопасный; легковоспламеняющийся

to be subjected to подлежать

contamination загрязнение; механические примеси

malfunction нарушение нормальной работы, сбой

valve seating притирка клапана, седло клапана

stringent строгий; обязательный, точный

to enhance увеличивать, усиливать, улучшать

load-carrying capacity грузоподъёмность; подъёмная сила;

smothering гашение, тушение, удушье

catapult retracting engines катапультное устройство

jet blast deflectors отражатель реактивной струи

handling systems системы для работы, транспортировки

There have been many liquids tested for use in hydraulic systems.

Currently, liquids being used include mineral oil, water, phosphate ester, water-based ethylene glycol compounds, and silicone fluids. The three most common types of hydraulic liquids are petroleum-based, synthetic fire-resistant, and water-based fire-resistant.

The most common hydraulic fluids used in shipboard systems are the petroleum-based oils.

These fluids contain additives to protect the fluid from oxidation (antioxidant), to protect system metals from corrosion (anticorrosion), to reduce tendency of the fluid to foam (foam suppressant), and to improve viscosity.

Petroleum-based fluids are used in surface ships’ electrohydraulic steering and deckmachinery systems, submarines’ hydraulic systems, and aircraft automatic pilots, shock absorbers, brakes, control mechanisms, and other hydraulic systems using seal materials compatible with petroleum-based fluids.

Petroleum-based oils contain most of the desired properties of a hydraulic liquid. However, they are flammable under normal conditions and can become explosive when subjected to high pressures and a source of flame or high temperatures. Nonflammable synthetic liquids have been developed for use in hydraulic systems where fire hazards exist.

Cleanliness in hydraulic systems has received considerable attention recently. Some hydraulic systems, such as aerospace hydraulic systems, are extremely sensitive to contamination. Fluid cleanliness is of primary importance because contaminants can cause component malfunction, prevent proper valve seating, cause wear in components, and may increase the response time of servo valves.

The inside of a hydraulic system can only be kept as clean as the fluid added to it. Initial fluid cleanliness can be achieved by observing stringent cleanliness requirements or by filtering all fluid added to the system.

The most widely used water-based hydraulic fluids may be classified as water-glycol mixtures and water-synthetic base mixtures. The water- glycol mixture contains additives to protect it from oxidation, corrosion, and biological growth and to enhance its load-carrying capacity.

Fire resistance of the water mixture fluids depends on the vaporization and smothering effect of steam generated from the water. The water in water-based fluids is constantly being driven off while the system is operating. Therefore, frequent checks to maintain the correct ratio of water are important. The water-based fluid used in catapult retracting engines, jet blast deflectors, and weapons elevators and handling systems. (from http://www.tpub.com/content/engine/14105/css/14105_39.htm)

• Look through the text again and decide if the following statements true or false:

1. There are a lot of types of hydraulic liquids and some of them include mineral oils.

2. The most wide-spread hydraulic fluids are synthetic fire-resistant fluids.

3. The main function of hydraulic fluids is to protect system metals from corrosion.

4. Petroleum-based fluids are used in catapult retracting engines, jet blast deflectors.

5. The hydraulic systems are not sensitive to contamination.

6. Cleanliness in hydraulic systems is very important.

• Match the following words with their definitions:

fluid a. the exertion of continuous force on a body by another

mixture b. petroleum

pressure c. a substance, liquid, lacking definite shape

oil d. ingredients mixed together to produce a substance

freezing point e. reduced to a simpler molecular structure

compound f. operated by liquid

hydraulic g. a mixture of two or more things

degradable h. a level of temperature at which a change of state occurs

• Change the following sentences into the Active or the Passive:

1. Petroleum-based fluids are used in surface ships’ electrohydraulic steering and deckmachinery systems.

2. Liquids being used include mineral oil, water, phosphate ester, water-based ethylene glycol compounds, and silicone fluids.

3. Nonflammable synthetic liquids have been developed for use in hydraulic systems where fire hazards exist.

4. Cleanliness in hydraulic systems has received considerable attention recently.

5. The most widely used water-based hydraulic fluids may be classified as water-glycol mixtures and water-synthetic base mixtures.

6. The water in water-based fluids is constantly being driven off while the system is operating.

• Give English definitions to the following words in Russian:

Гидравлическая жидкость, гидросистема, вязкость, испарение, антикоррозионный, минеральное масло, антиокислительный, клапан, присадка, высокая температура, вспышка, амортизатор, противообледенительный агент, рабочее тело, гидропривод, гликоль, эфир, амортизационная жидкость, тормозной, давление, антипенный, органическое соединение.

• Translate from Russian into English:

Гидравлические жидкости — жидкости, применяемые в машинах и механизмах для передачи усилий, которые передаются через жидкую среду для приведения в действие исполнительных механизмов. Гидравлические жидкости используют в гидропередачах самолетов, экскаваторов, кранов, бульдозеров и других машин, в тормозных системах автомобилей, в гидравлических системах промышленного оборудования и т.д.

Гидравлические жидкости должны обладать определенным комплексом физико-химических и эксплуатационных свойств. Они должны быть устойчивыми при хранении и эксплуатации, не образовывать осадков; обладать малой вспениваемостью, хорошими смазочными и противоизносными свойствами; не содержать механических загрязнений, особенно абразивных частиц, их вязкость не должна резко изменяться с температурой. Кроме того, гидравлические жидкости не должны вызывать коррозию металлов и разрушать другие конструкционные материалы. В ряде случаев необходимы негорючие жидкости.

Во все специальные жидкости вводят, как правило, антикоррозионные присадки, в гидравлические – тормозные и амортизаторные, кроме того – вязкостные, противоизносные и антиокислительные, а в охлаждающие – антипенные присадки. Антиобледенительные жидкости получают обычно смешением этилового спирта с водой.

Нефтехимическая промышленность выпускает более 20 сортов минеральных масел, используемых в гидравлических системах.

(With the help of http://www.xumuk.ru/encyklopedia/1009.html)

• Split into 2-3 groups. The task of each group is to invent a new hydraulic fluid. It’s up to you to decide what kind of vehicle it will refer to. Describe the components of your fluid and tell what functions each component will be responsible for. Give it the name and describe the performance of your fluid.

Use the following words and phrases:

to be broadly used as

to be for use in

to be designed for

to employ sth

to possess

suitable

conventional

in comparison to

to be applied in

content

to contain

• Read the ad. Its tone is rather reserved. You have just developed an innovative hydraulic fluid which needs to be promoted on the market.

Chevron Aviation Hydraulic Fluids are both manufactured from specially selected, highly refined, low viscosity and low pour point petroleum base stocks. They both contain a superior, shear resistant viscosity index improver, which provides an extremely high viscosity index. They also contain an antiwear agent and an oxidation inhibitor. Both contain a red colored dye to hasten identification.

The low viscosity of the base stock used for these fluids and the shear stable viscosity index improver provide the extremely high viscosity index (300+) which is critical for a lubricant or hydraulic fluid operating over the very broad temperature range of -54°C to 135°C.

Since this is a conventional petroleum base stock, and not a synthetic, the low pour point is critical to minimize filter plugging.

In addition, the antiwear additive and foam inhibitor help prevent pump cavitation and can extend both pump and servo valve life.

(From http://www.matweb.com/search/datasheettext)

Unit 3

Text Common hydraulic failures

(questions and answers)

• Can you mention any common hydraulic failures? Are you familiar with them?

• Have you ever fixed a car? What are your impressions? Think a little and prepare a short story about your experience or about your friend or a relative.

Words and phrases:

сontamination загрязнение; механические примеси

clearance (радиальный) зазор; просвет; промежуток

abrasion абразия; стирание, износ, шлифовка

scoring количественная оценка, задирание

to slide скользить,

axial осевой, продольный

cylinder barrel блок цилиндров

valve plate пластина клапана, клапанная доска

lubricating film смазочная плёнка

rod seal уплотнение штока (цилиндра), штабиковый спай

to exceed превосходить

aeration аэрация, насыщение кислородом

to convert превращать, изменять

to dissipate рассеивать

viscosity вязкость, коэффициент вязкости

inherent собственный, присущий, свойственный

capacity вместимость, основная характеристика

umbilical занимающий центральное положение, округленный

• Translate the forms of the verbs in bold type say what functions do they play in the sentences of the text given below:

air is drawn, it explodes when pressurized, the volume of fluid being demanded by the rod side of the cylinder, most rod seals are designed keep high-pressure fluid in, it can be expressed as, to achieve stable fluid temperature, an efficiency of 80% needs to be capable of dissipating a heat load, there are two ways to solve overheating problems, decreasing this heat load to an acceptable level, by replacing the pressure, the most economical solution was to install additional cooling capacity.

Common hydraulic failures

• How does contamination cause this type of damage to a hydraulic pump?

When hydraulic fluid is contaminated with hard particles that are the same size as the clearance between two lubricated surfaces, a process known as three-body abrasion occurs. Three-body abrasion results in scoring and heavy wear of sliding surfaces.

• What other explanations are there for this type of damage?

In axial piston designs, the cylinder barrel is hydrostatically loaded against the valve plate. The higher the operating pressure, the higher the hydrostatic force holding the cylinder barrel and valve plate in contact. However, if operating pressure exceeds design limits or if the valve plate is not in proper contact with the cylinder barrel, the cylinder barrel separates from the valve plate. Once separation occurs, the lubricating film is lost, the two surfaces come into contact and a process known as two-body abrasion occurs.

• What is the 'diesel effect'?

The diesel effect occurs in a hydraulic cylinder when air is drawn past the rod seals, mixes with the hydraulic fluid and explodes when pressurized.

• How does this affect a hydraulic cylinder?

When a double-acting hydraulic cylinder retracts under the weight of its load, the volume of fluid being demanded by the rod side of the cylinder can exceed the volume of fluid being supplied by the pump.

When this happens, a negative pressure develops in the rod side of the hydraulic cylinder, which usually results in air being drawn into the cylinder past its rod seals. This occurs because most rod seals are designed keep high-pressure fluid in and are not designed to keep air out. The result of this is aeration – the mixing of air with the hydraulic fluid.

Aeration causes damage through loss of lubrication and overheating, and when a mixture of air and oil is compressed it can explode, damaging the hydraulic cylinder and burning its seals.

• Why do hydraulic systems overheat?

Heating of hydraulic fluid in operation is caused by inefficiencies. Inefficiencies result in losses of input power, which are converted to heat. A hydraulic system's heat load is equal to the total power lost (PL) through inefficiencies and can be expressed as:

PLtotal = PLpump + PLvalves + PLplumbing + PLactuators

If the total input power lost to heat is greater than the heat dissipated, the hydraulic system will eventually overheat.

• Hydraulic fluid temperature – how hot is 'too hot'?

Hydraulic fluid temperatures above 180°F (82°C) damage most seal compounds and accelerate degradation of the oil. While the operation of any hydraulic system at temperatures above 180°F should be avoided, fluid temperature is too high when viscosity falls below the optimum value for the hydraulic system's components. This can occur well below 180°F, depending on the fluid's viscosity grade.

• Maintaining stable hydraulic fluid temperature

To achieve stable fluid temperature, a hydraulic system's capacity to dissipate heat must exceed its inherent heat load. For example, a system with continuous input power of 100 kW and an efficiency of 80% needs to be capable of dissipating a heat load of at least 20 kW. It's important to note that an increase in heat load or a reduction in a hydraulic system's capacity to dissipate heat will alter the balance between heat load and dissipation.

• Beat the heat

There are two ways to solve overheating problems in hydraulic systems: decrease heat load; or increase heat dissipation.

Decreasing heat load is always the preferred option because it increases the efficiency of the hydraulic system. For example, the heat load of the umbilical alone is nearly 30% of available input power, a figure that would normally be considered unacceptable. Decreasing this heat load to an acceptable level would have involved reducing the pressure drop, by replacing the pressure and return lines in the umbilical with larger diameter hoses. The cost of doing this for what was a temporary installation meant that, in this case, the most economical solution was to install additional cooling capacity in the circuit.

(from http://www.hydraulicsupermarket.com/technical.html)

• Answer the following questions in your own words:

1. What are the typical hydraulic failures?

2. What happens if the cylinder barrel separates from the valve plate?

3. What aeration is?

4. How can you prevent hydraulic systems from overheating?

5. Why hot hydraulic fluids cause damage?

6. Is it necessary to maintain stable hydraulic fluid temperature? Why?

• Look at the constructions given below. What is peculiar about these constructions? Read the sentences which may give you a hint:

I have just had my car washed.

I washed my car two hours ago.

Which sentence means someone did it for me?

Have + something + Past Participle

Something + need + Verb + ing

Something + need to be + Past Participle

• Change the following sentences using these grammar constructions:

1. The mechanic removed the pedal assembly, the booster, then the master cylinder.

2. The workers replaced the brake lines with new and removed the calipers that were no longer attached to the old discs.

3. We thought of removing the distribution block after disconnecting the line that feeds the rear brakes.

4. My dad asked me to make sure the part is compatible with your make, model and year of car.

• Make the text given above shorter and dramatize it turning it into the report for the programme Top-Gear.

You can use the following phrases to make your point of view clear:

I suggest/recommend that...

Have I made that clear?

Do you see what I'm getting at?

Would you mind... I wonder if you could...

I'm afraid I don't quite understand what you are getting at.

Could you explain to me how that is going to work?

I don't see what you mean. Could we have some more details, please?

Do you mean that...?

Is it true that...?

Do you (really) think that...

How do you feel about...?

I never thought about it that way before.

Good point!

I get your point.

That's (exactly) the way I feel.

• Reading for fun. Work in pairs. Read this article, translate and discuss with your groupmates. Of course it’s a joke but what if…? Are there any real ground for such kind of humor?

While reading the text pay special attention to grammar. What is peculiar about the text from the point of view of grammar?