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and alkaline additives to neutralize acidic oxidation products of the oil. Most commercial oils have a minimal amount of zinc dialkyldithiophosphate as an anti-wear additive to protect contacting metal surfaces with zinc and other compounds in case of metal to metal contact. The quantity of zinc dialkyldithiophosphate is limited to minimize adverse effect on catalytic converters. Another aspect for after-treatment devices is the deposition of oil ash, which increases the exhaust back pressure and reduces over time the fuel economy. The so-called "chemical box" limits today the concentrations of sulfur, ash and phosphorus (SAP).

There are other additives available commercially which can be added to the oil by the user for purported additional benefit. Some of these additives include: zinc dialkyldithiophosphate (ZDDP) additives, which typically also contain calcium sulfonates, are available to consumers for additional protection under extreme-pressure conditions or in heavy duty performance situations. ZDDP and calcium additives are also added to protect motor oil from oxidative breakdown and to prevent the formation of sludge and varnish deposits.

In the 1980s and 1990s, additives with suspended PTFE particles were available e.g. "Slick50" to consumers to increase motor oil's ability to coat and protect metal surfaces. There is controversy as to the actual effectiveness of these products as they can coagulate and clog the oil filters.

Some molybdenum disulfide containing additives to lubricating oils are claimed to reduce friction, bond to metal, or have anti-wear properties. They were used in WWII in flight engines and became commercial after WWII until the 1990s. They were commercialized in the 1970s (ELF ANTAR Molygraphite) and are today still available (Liqui Moly MoS2 10 W-40, www.liqui-moly.de).

Synthetic oil and synthetic blends. Synthetic lubricants were first synthesized, or man-made, in significant quantities as replacements for mineral lubricants (and fuels) by German scientists in the late 1930s and early 1940s because of their lack of sufficient quantities of crude for their (primarily military) needs. A significant factor in its gain in popularity was the ability of synthetic-based lubricants to remain fluid in the sub-zero temperatures of the Eastern front in wintertime, temperatures which caused petroleum-based lubricants to solidify due to their higher wax content. The use of synthetic lubricants widened through the 1950s and 1960s due to a property at the other end of the temperature spectrum, the ability to lubricate aviation engines at temperatures that caused mineral-based lubricants to break down. In the mid 1970s, synthetic motor oils were formulated and commercially applied for the first time in automotive applications. The same SAE system for designating motor oil viscosity also applies to synthetic oils.

Instead of making motor oil with the conventional petroleum base, "true" synthetic oil base stocks are artificially synthesized. Synthetic oils are derived

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from either Group III mineral base oils, Group IV, or Group V non-mineral bases. True synthetics include classes of lubricants like synthetic esters as well as "others" like GTL (Methane Gas-to-Liquid) (Group V) and polyalpha-olefins (Group IV). Higher purity and therefore better property control theoretically means synthetic oil has good mechanical properties at extremes of high and low temperatures. The molecules are made large and "soft" enough to retain good viscosity at higher temperatures, yet branched molecular structures interfere with solidification and therefore allow flow at lower temperatures. Thus, although the viscosity still decreases as temperature increases, these synthetic motor oils have a much improved viscosity index over the traditional petroleum base. Their specially designed properties allow a wider temperature range at higher and lower temperatures and often include a lower pour point. With their improved viscosity index, true synthetic oils need little or no viscosity index improvers, which are the oil components most vulnerable to thermal and mechanical degradation as the oil ages, and thus they do not degrade as quickly as traditional motor oils. However, they still fill up with particulate matter, although at a lower rate compared to conventional oils, and the oil filter still fills and clogs up over time. So, periodic oil and filter changes should still be done with synthetic oil; but some synthetic oil suppliers suggest that the intervals between oil changes can be longer, sometimes as long as 16,000-24,000 km (10,000–15,000 mi).

With improved efficiency, synthetic lubricants are designed to make wear and tear on gears far less than with petroleum-based lubricants, reduce the incidence of oil oxidation and sludge formation, and allow for "long life" extended drain intervals. Today, synthetic lubricants are available for use in modern automobiles on nearly all lubricated components, potentially with superior performance and longevity as compared to non-synthetic alternatives. Some tests[citation needed] have shown that fully synthetic oil is superior to conventional oil in many respects, providing better engine protection, performance, and better flow in cold starts than petroleum-based motor oil.

Maintenance. In engines, there is inevitably some exposure of the oil to products of internal combustion, and microscopic coke particles from black soot accumulate in the oil during operation. Also the rubbing of metal engine parts inevitably produces some microscopic metallic particles from the wearing of the surfaces. Such particles could circulate in the oil and grind against the part surfaces causing wear. The oil filter removes many of the particles and sludge, but eventually the oil filter can become clogged, if used for extremely long periods. The motor oil and especially the additives also undergo thermal and mechanical degradation. For these reasons, the oil and the oil filter need to be periodically replaced.

The vehicle manufacturer may specify which SAE viscosity grade of oil should be used for the vehicles it produces, but many different weights can

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actually be used. Some manufacturers have specific quality test requirements or "specs" for service in their particular make. In the USA, most quick oil change shops recommended intervals of 5,000 km (3,000 mi) or every 3 months which is not necessary according to new car manuals from manufacturers. This has led to a 3,000 mile myth among most Americans.

With a degree of ambiguity about how many miles motor oil is actually good for, some people opt for a more convenient time-based schedule. Seasonal changes are desirable where the viscosity can be adjusted for the ambient temperature change, thicker for summer heat and thinner for the winter cold. As a general rule, the thinnest oil that does not produce excess wear is used. Timebased intervals account for both the short trip driver who does fewer miles, but builds up more contaminates, as well as the long highway trips that are much easier on the oil. Many modern cars now list somewhat higher intervals for changing of oil and filter, with the constraint of "severe" service requiring more frequent changes with less-than ideal driving; contrary to what most people think, this applies to short trips of under 16 km (10 mi), where the oil does not get to full operating temps long enough to burn off condensation, excess fuel, and other contamination that leads to "sludge", "varnish", "acids", or other deposits. In contrast, an engine which runs continually for hours, such as for a taxi, or long-distance driving, is considered "normal" service. Many manufacturers have engine computer calculations to estimate the oil's condition based on the factors which degrade it such as RPMs, temperatures, and trip length; and one system adds an optical sensor for determining the clarity of the oil in the engine. These systems are commonly known as Oil Life Monitors or OLMs. Over the years, manufacturers have been able to reduce the viscosity of oil needed to correctly lubricate the engine and extend the duration of the servicable life. In the 1970s, typical cars took heavy 10W-40 oil which was used for a duration of 3,250 km (2,000 mi) or less. In the 1980s, 5W-30 oils were introduced to improve gas mileage and engine performance. A modern typical application would be Honda Motor's use of 5W-20 viscosity oil for 12,000 km (7,500 mi) without excess wear or deposits, while offering maximum mpg. Most other manufacturers use 20-weight oils as well. The latest API "SM" spec offers a substantially better product than preceding specifications.

Language practice

1. Match English words with their Russian definitions:

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2. Match the words with the similar meaning:

3. Make up all possible derivatives from the following words and

translate them in Russian:

1.Using all phrases and word structures from section “Language practice” describe operating principals of fluids in the car.

2.Enumerate the qualities that must have automotive oil and oil’s functions.

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3. Using phrases and word structures from section “Language practice” write your own report about:

a)check/replace fuel filters

b)check or refill windshield washer fluid

c)check or flush brake fluid

d)check and flush engine coolant

Unit 8.

Section A. The importance of graphics

Theory

In addition to the writing portion of your report you might want to consider including pictures or graphics. Graphics today form part of any standard business report. There is also often an alignment between graphics and any supporting visual presentation (PowerPoint) offered in support of any business proposal or argument. However, since the goal in a business report is to convey information clearly to the reader, a graphic can be clearer than text.

If you wanted to show a financial or operational trend for a commercial period, a line or bar graphic would be the most effective format. Some of the more common graphics that you might want to consider would include:

Tables,

Pie Charts,

Line Charts,

Bar Charts,

Organizational charts,

Others (pictograms, maps, photographs, time lines, flow charts, etc.).

Remember, that the ART to successful business reporting is being able to communicate and sell the report, and accordingly graphics must be located within the center of the report and relative to key findings or statements. Work the graphic into the flow of your text. Place the graphic within the text immediately after the paragraph in which the graphic is first mentioned. Refer to each graphic by its future number, which must correspond to the section of the report (Chapter) and the sequence of the features.

Questions:

1.What is the role of graphics in the structure of modern business report?

2.Why is it important to use graphics?

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3.What is the most effective format to show a financial or operational trend for a commercial period?

4.What are the most common graphics?

5.Where graphics should be located?

Section B. Reliability

Reading

1.What questions does this text need to answer?

2.What type of information the author required answering these questions?

3.What are possible sources of this information?

Reliability engineeringis an engineering field, that deals with the study of reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time.[1] It is often reported in terms of a probability.

Reliability may be defined in several ways:

The idea that something is fit for purpose with respect to time;

The capacity of a device or system to perform as designed;

The resistance to failure of a device or system;

The ability of a device or system to perform a required function under stated conditions for a specified period of time;

The probability that a functional unit will perform its required function for a specified interval under stated conditions.

The ability of something to "fail well" (fail without catastrophic consequences)

Reliability engineers rely heavily on statistics, probability theory, and reliability theory. Many engineering techniques are used in reliability engineering, such as reliability prediction, well build analysis, thermal management, reliability testing and accelerated life testing. Because of the large number of reliability techniques, their expense, and the varying degrees of reliability required for different situations, most projects develop a reliability program plan to specify the reliability tasks that will be performed for that specific system.

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The function of reliability engineering is to develop the reliability requirements for the product, establish an adequate reliability program, and perform appropriate analyses and tasks to ensure the product will meet its requirements. These tasks are managed by a reliability engineer, who usually holds an accredited engineering degree and has additional reliability-specific education and training. Reliability engineering is closely associated with maintainability engineering and logistics engineering. Many problems from other fields, such as security engineering, can also be approached using reliability engineering techniques. This article provides an overview of some of the most common reliability engineering tasks. Please see the references for a more comprehensive treatment.

Many types of engineering employ reliability engineers and use the tools and methodology of reliability engineering. For example:

System engineers design complex systems having a specified reliability

Mechanical engineers may have to design a machine or system with a specified reliability

Automotive engineers have reliability requirements for the automobiles (and components) which they design

Electronics engineers must design and test their products for reliability requirements.

In software engineering and systems engineering the reliability engineering is the subdiscipline of ensuring that a system (or a device in general) will perform its intended function(s) when operated in a specified manner for a specified length of time. Reliability engineering is performed throughout the entire life cycle of a system, including development, test, production and operation.

Reliability theory is the foundation of reliability engineering. For engineering purposes, reliability is defined as the probability that a device will perform its intended function during a specified period of time under stated conditions. Mathematically, this may be expressed as where is the failure probability density function and t is the length of the period of time (which is assumed to start from time zero).

Reliability engineering is concerned with four key elements of this definition:

First, reliability is a probability. This means that failure is regarded as a random phenomenon: it is a recurring event, and we do not express any information on individual failures, the causes of failures, or relationships between failures, except that the likelihood for failures to occur varies over time according to the given probability function. Reliability

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engineering is concerned with meeting the specified probability of success, at a specified statistical confidence level.

Second, reliability is predicated on "intended function:" Generally, this is taken to mean operation without failure. However, even if no individual part of the system fails, but the system as a whole does not do what was intended, then it is still charged against the system reliability. The system requirements specification is the criterion against which reliability is measured.

Third, reliability applies to a specified period of time. In practical terms, this means that a system has a specified chance that it will operate without failure before time. Reliability engineering ensures that components and materials will meet the requirements during the specified time. Units other than time may sometimes be used. The automotive industry might specify reliability in terms of miles, the military might specify reliability of a gun for a certain number of rounds fired. A piece of mechanical equipment may have a reliability rating value in terms of cycles of use.

Fourth, reliability is restricted to operation under stated conditions. This constraint is necessary because it is impossible to design a system for unlimited conditions. A Mars Rover will have different specified conditions than the family car. The operating environment must be addressed during design and testing. Also, that same rover, may be required to operate in varying conditions requiring additional scrutiny.

4.What kind of methodology was used in this text (explanation, description, proof, demonstration, comparison)?

5.Does this text need to be illustrated or not?

6.Was the given information explained enough?

7.Does it need to be continued?

Speaking

1.Is there any managerial or commercial position in this text?

2.Do you consider information given in this text accurate?

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3.Why do you think so?

4.Do you consider information given in this text objective?

5.Is this report made in one writing style or not?

6.What kind of style is it?

7.Give characteristics of this style?

8.What attributes are common to it?

9.What kind of aspects were lightened there positive or negative? Or

may be neutral?

10.What kinds of graphics were used in this text?

Discussing

1.Discuss Reliability program plan for an automobile.

2.What should be used to achieve it’s reliability?

3.What should be taken into consideration?

4.What kind of tasks must this plan include?

5.What kind of methods should be used?

6.What kind of instruments should be applied?

7.What must be done with the results of tests?

8.Compare your Plan with the plan given below. What is common and distinguishing in it?

Reliability Sequential Test Plan

The purpose of reliability testing is to discover potential problems with the design as early as possible and, ultimately, provide confidence that the system meets its reliability requirements.

Reliability testing may be performed at several levels. Complex systems may be tested at component, circuit board, unit, assembly, subsystem and system levels. (The test level nomenclature varies among applications.) For example, performing environmental stress screening tests at lower levels, such as piece parts or small assemblies, catches problems before they cause failures at higher levels. Testing proceeds during each level of integration through full-up system testing, developmental testing, and operational testing, thereby reducing program risk. System reliability is calculated at each test level. Reliability growth techniques and failure reporting, analysis and corrective active systems (FRACAS) are often employed to improve reliability as testing progresses. The drawbacks to such extensive tests are time and expense. Customers may choose to accept more risk by eliminating some or all lower levels of testing.

It is not always feasible to test all system requirements. Some systems are prohibitively expensive to test; some failure modes may take years to observe; some complex interactions result in a huge number of possible test cases; and

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some tests require the use of limited test ranges or other resources. In such cases, different approaches to testing can be used, such as accelerated life testing, design of experiments, and simulations.

The desired level of statistical confidence also plays an important role in reliability testing. Statistical confidence is increased by increasing either the test time or the number of items tested. Reliability test plans are designed to achieve the specified reliability at the specified confidence level with the minimum number of test units and test time. Different test plans result in different levels of risk to the producer and consumer. The desired reliability, statistical confidence, and risk levels for each side influence the ultimate test plan. Good test requirements ensure that the customer and developer agree in advance on how reliability requirements will be tested.

A key aspect of reliability testing is to define "failure". Although this may seem obvious, there are many situations where it is not clear whether a failure is really the fault of the system. Variations in test conditions, operator differences, weather, and unexpected situations create differences between the customer and the system developer. One strategy to address this issue is to use a scoring conference process. A scoring conference includes representatives from the customer, the developer, the test organization, the reliability organization, and sometimes independent observers. The scoring conference process is defined in the statement of work. Each test case is considered by the group and "scored" as a success or failure. This scoring is the official result used by the reliability engineer.

As part of the requirements phase, the reliability engineer develops a test strategy with the customer. The test strategy makes trade-offs between the needs of the reliability organization, which wants as much data as possible, and constraints such as cost, schedule, and available resources. Test plans and procedures are developed for each reliability test, and results are documented in official reports.

Study the example of the plan of Accelerated testing and give your own plan of the test of any other car system.

Accelerated testing

The purpose of accelerated life testing is to induce field failure in the laboratory at a much faster rate by providing a harsher, but nonetheless representative, environment. In such a test the product is expected to fail in the lab just as it would have failed in the field—but in much less time. The main objective of an accelerated test is either of the following:

To discover failure modes

To predict the normal field life from the high stress lab life

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