Cylinder Deactivation Variable Engine Displacement

What is cylinder deactivation? It is a method used to create a variable displacement engine that is able to supply the full power of a large engine under high load conditions as well as the fuel economy of a small engine for cruising. The Case for Cylinder Deactivation In typical light load driving with large displacement engines (e.g. highway cruising), only about 30 percent of an engine’s potential power is utilized. Under these circumstances, the throttle valve is only slightly open and the engine has to work hard to draw air through it. The result is an inefficient condition known as pumping loss. In this situation, a partial vacuum occurs between the throttle valve and the combustion chamber—and some of the power that the engine makes is used not to propel the vehicle forward, but to overcome the drag on the pistons and crank from fighting to draw air through the small opening and the accompanying vacuum resistance at the throttle valve. By the time one piston cycle is complete, up to half of the potential volume of the cylinder has not received a full charge of air. Cylinder Deactivation to the Rescue Deactivating cylinders at light load forces the throttle valve be opened more fully to create constant power, and allows the engine to breathe easier. Better airflow reduces drag on the pistons and the associated pumping losses. The result is improved combustion chamber pressure as the piston approaches top dead center (TDC) and the spark plug is about to fire. Better combustion chamber pressure means a more potent and efficient charge of power is unleashed on the pistons as they thrust downward and rotate the crankshaft. The net result? Improved highway and cruising fuel mileage. How Does it All Work? In a nutshell, cylinder deactivation is simply keeping the intake and exhaust valves closed through all cycles for a particular set of cylinders in the engine. Depending on the design of the engine, valve actuation is controlled by one of two common methods: For pushrod designs—when cylinder deactivation is called for—the hydraulic valve lifters are collapsed by using solenoids to alter the oil pressure delivered to the lifters. In their collapsed state, the lifters are unable to elevate their companion pushrods under the valve rocker arms, resulting in valves that cannot be actuated and remain closed.For overhead cam designs, generally a pair of locked-together rocker arms is employed for each valve. One rocker follows the cam profile while the other actuates the valve. When a cylinder is deactivated, solenoid controlled oil pressure releases a locking pin between the two rocker arms. While one arm still follows the camshaft, the unlocked arm remains motionless and unable to activate the valve. By forcing the engine valves to remain closed, an effective â€Å"spring† of air is created inside the deactivated cylinders. Trapped exhaust gasses (from previous cycles before the cylinders were deactivated) are compressed as the pistons travel on their upstroke and then decompressed and push back on the pistons as they return on their down stroke. Because the deactivated cylinders are out of phase, (some pistons traveling up while others are traveling down), the overall effect is equalized. The pistons are actually just going along for the ride. To complete the process, fuel delivery for each deactivated cylinder is cut-off by electronically disabling the appropriate fuel injection nozzles. The transition between normal operation and deactivation is smoothed by subtle changes in ignition and camshaft timing as well as throttle position all managed by sophisticated electronic control systems. In a well-designed and executed system, the switching back-and-forth between both modes is seamless—you really don’t feel any difference and have to consult the dash gauges to know that its happened. Read more about cylinder deactivation at work in our review of the GMC Sierra SLT flex-fuel, and see the instant fuel economy it generates in the GMC Sierra test drive photo gallery.

The Portrayal Of Women s Crime And Punishment And The...

The Portrayal of Women in Crime and Punishment and the Communist Manifesto Women are discussed and or portrayed in both â€Å"Crime and Punishment† by Fyodor Dostoevsky and â€Å"The Communist Manifesto† by Karl Marx and Friedrich Engels. In â€Å"Crime and Punishment† there are several female characters, many of which play large roles in the main characters’ story. However, women are only mentioned a few times in â€Å"The Communist Manifesto†, but it is essential to the point the authors are trying to convey. Each of these literatures see women and different ways, some more positive, negative, and or diverse. Nonetheless, I believe both pieces of literature see women as vital or essential aspects of society. The Communist Manifesto tries to explain the goals of communism as well as the theory behind it. It focuses on how class struggles and the oppression of one class by another are a problem. Women are not mentioned throughout the book except for when the bourgeois are discussed. Marx and Engels state,† The less the skill and exertion of strength implied in manual labour, in other words, the more modern industry becomes developed, the more is the labour of men superseded by that of women. Differences of age and sex have no longer any distinctive social validity for the working class. All are instruments of labour, more or less expensive to use, according to their age and sex† (pg. 73). The communist are worried that as modern industry grows the work required could be done by women andShow MoreRelatedReligion Is Poison8248 Words   |  33 Pagesset of beliefs or teachings about the deepest and most elusive of life’s mysteries. So, from this point of view, I will leav e my paper to research those that have a belief in a ‘theistic god’ rather than the all-inclusive. Deprived of this belief, it s really not a viable theistic religion. George H. Smith in his book, â€Å"Atheism: The Case Against God,†1974, commented, â€Å"†¦the belief in god is irrational to the point of absurdity; and that this irrationality, when manifested in specific religions suchRead MoreLgbt19540 Words   |  79 Pagesexplained in more detail here. Lesbian A lesbian woman is one who is romantically, sexually and/or emotionally attracted to women. Many lesbians prefer to be called lesbian rather than gay. Gay A gay man is one who is romantically, sexually and/or emotionally attracted to men. The word gay can be used to refer generally to lesbian, gay and bisexual people but many women prefer to be called lesbian. Most gay people dont like to be referred to as homosexual because of the negative historical associations

Essay on Aboriginal People of Canada - 1267 Words

Aboriginal People of Canada Over the past decades, Aboriginal people (the original people or indigenous occupants of a particular country), have been oppressed by the Canadian society and continue to live under racism resulting in gender/ class oppression. The history of Colonialism, and Capitalism has played a significant role in the construction and impact of how Aborignal people are treated and viewed presently in the Canadian society. The struggles, injustices, prejudice, and discrimination that have plagued Aboriginal peoples for more than three centuries are still grim realities today. The failures of Canadas racist policies toward Aboriginal peoples are reflected in the high levels of unemployment and poor education.†¦show more content†¦The British were interested in the production and circulation of fur as a commodity in the world market and were in need of labor. The Indians were the only available source of skilled labor, so they became part of the production process. From Colonialization, Capitalism came which resulted in the disintegration of communal and egalitarian societies that the indigenous created, which in turn, became the exploited labor force in the commodity production. European ethnocentrism and racism also affected patterns of Aboriginal socialization. Since most whites viewed all aspects of indigenous life to be culturally and morally inferior, missionaries made efforts to eliminate the egalitarianism customs of Aboriginal societies and to promote the norms of the dominant European patriarchal society. The perceived differences between men and women led to cultural genocide. Capitalism is an economic and social system that focuses on pursuit of profit. It has also involved the presence of exchange of goods for money or other goods, and the organization of production and distribution of goods . One example of this is the Hudsons Bay fur trade. The fur trade of the Hudsons Bay basin initially transformed the indigenous communal societies in order to exploit Indian labor in the commodity production of fur (Bourgeault, 41). Capitalism uses market relations (including class relationship) #8230;Capitalism centered in the RedShow MoreRelatedThe Aboriginal People Of Canada1410 Words   |  6 PagesCanadian Native Aboriginals Introduction The Canadian native aboriginals are the original indigenous settlers of North Canada in Canada. They are made up of the Inuit, Metis and the First nation. Through archeological evidence old crow flats seem to the earliest known settlement sites for the aboriginals. Other archeological evidence reveals the following characteristics of the Aboriginal culture: ceremonial architecture, permanent settlement, agriculture and complex social hierarchy. A numberRead MoreHow The Cost Of Shelters And Age Distribution Affects The Aboriginal People Of Canada3454 Words   |  14 Pages The Relationship Among Aboriginal Population, Age and Shelter Costs Course: SOC222H Professor’s Name Riva Lieflander Name: Yingjun Li Student ID: 1000677957 Date: 04/20/2015 Introduction The 2006 Census Public Use Microdata File (PUMF) involved a total of 844,476 people. Participants were randomly selected in a manner that represented all social characteristics that existed among Canadians. Technically, it was estimated that the number represented only 2.7% of the Canadian population. ItRead MoreThe Aboriginal Peoples Of Canada1404 Words   |  6 Pages The Aboriginal peoples of Canada had gone through many situations to get to where they are today with their education system. Pain, sorrow, doubt, and hope are all feelings brought to mind when thinking about the history and the future of Aboriginal education. By taking a look at the past, anyone can see that the right to education for Aboriginal peoples has been fought about as early as the 1870s. This is still is a pressing issue today. Elder teachings, residential, reserve and post-secondaryRead MoreThe Aboriginal Peoples Of Canada950 Words   |  4 PagesINTRODUCTION: Concerns of violent victimization and self-destructive tendencies in Aboriginal communities have become a significant issue in Aboriginal movements worldwide. In Canada, it has taken the specific form of feminist-inspired campaigns for only those Indigenous females that are missing and murdered. The highly vocalized 2015 campaign for the 42nd Canadian Federal Election drew much attention to the fate of missing and murdered Indigenous women. However, the attention on females suggestsRead MoreEssay about Aboriginal People of Canada1281 Words   |  6 Pages Aboriginal people represent less than 3% of the total population in BC. Yet, they account for more than 9% of all suicides in BC (Chandler). The numbers of suicides amongst aboriginal youth are even more alarming – nearly one-fourth of all youth suicides in BC are committed by aboriginals and more than half of all aboriginal suicides are committed by youth (Chandler). The fact that indigenous communities in Canada have the highest rate of suicide of any culturally identifiable group in the worldRead MoreFirst Nation or Aboriginal People of Canada Essay1218 Words   |  5 Pages Canada is a nation of opportunity and freedom. People from all around the world immigrate to Canada to start a new life, to get away from war or poverty. Canada opens their arms to them and accepts them, and gives them money to get them started. But how about those who were here from the very beginning, before anyone else landed in Canada; the ones that are called First Nation people, or Aboriginals? What is the government doing for them? Why are First Nations people suffering the worst in CanadaRead MoreThe Canadian Government Enacted An Indian Act1468 Words   |  6 PagesThe Canadian government enacted an Indian Act in 1876 which outlines their approach towards the elimination of the Aboriginal government, land, religion, and so on. This policy’s central goal was to assimilate the entire aboriginal population into Canadian civilization. The act described how to categorize one as an Indian, how one could lose their Indian status, the abolition of Native traditions and practices, and much more. Through residential schooling, which was administered through the IndianRead MoreWhy is it Difficult to Define an Aboriginal Person?1336 Words   |  5 PagesAboriginal peoples occupied Canadian lands long before the country was established and yet their position within Canadian hierarchy is often questioned. Colonialism imposed Euro-Canadian standards on First Nations peoples, challenging socio-cultural traditions and norms in the process. The implications of this decision propagate a longstanding marginalization of Aboriginal people, which is still experienced today (Frideres and Gasacz 1). Historical circumstances have created an unbalanced dichotomyRead MoreWomen s Prevalence Of Diabetes1487 Words   |  6 Pagestypes of diabetes Aboriginal people are faced with. It is a type of diabetes that occ urs during pregnancy; when your body is unable to produce an adequate amount of insulin to cope with fluctuating hormones and a growing baby (Harris, Bhattacharyya, Dyck, Hayward, Toth, 2013). Although gestational diabetes mellitus (GMD) is seen throughout Canada, the cases are much higher in the countries’ Aboriginal population (Harris et al., 2013). It has an impact on not only the Aboriginal women affectedRead MoreCanada And The Twentieth Century1356 Words   |  6 Pagesthought Canada was to become. â€Å"The nineteenth century was the century of the United States. I think that we can claim that is it Canada that shall fill the twentieth century. â€Å" was said by Laurier and his words passed almost without notice at the time. However, it did not take long before his words had somehow been transformed into the most famous phrase in Canadian history, â€Å"The twentieth century belongs to Canada.† His words showed great confidence and pride in the actions t hat Canada was supposedly

Skywest , Inc. and the Regional Airline Industry in 2009 free essay sample

SKYWEST , INC. and the REGIONAL AIRLINE INDUSTRY IN 2009 WHAT ARE THE DOMINANT CHARACTERISTICS OF THE US REGIONAL AIRLINE INDUSTRY? Regional airlines specialize in short-haul flight services from small cities that do not have the facilities or frequency of passenger travel to support larger airports. Regional airlines used to travel shorter distances with inferior aircrafts, but today, regional aircraft are getting larger, faster, and flying longer ranges. Regional airlines are considered to be their own segment of airline carrier, the other 2 being network and low-cost. Larger regional carriers operate using a business model which relies on contracts with major carriers to generate revenue. Regional airlines sell all or most of their flights to larger carriers who offer long and short haul flights. Regional airlines conduct their businesses in one of two ways. As feeder airlines, contracting with major airlines or operating under their own brand name and providing service to small, isolated communities, where the airline is their only reasonable link to a larger town. We will write a custom essay sample on Skywest , Inc. and the Regional Airline Industry in 2009 or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page In this role, the term commuter airline is generally used. WHAT IS THE RELATIONSHIP OF THE INDUSTRY TO THE NATIONAL AND GLOBAL AIRLINES? Most of the revenues of the regional airline companies come from their contracts as feeder airlines for the major companies. They rely on each other in order to do business. Regional airlines that have partnerships with major national companies have an advantage because they are able to gain access to large established internet bases. In the partnership between the regional airlines and the big carriers, it is mostly the regional airline companies that control the power. This is mainly due to the fact that major airlines with international flights don’t have the capability to transport passengers from small communities to the big main airports themselves.