Land Rover smoking exhaust Economy issue of Automotive industry
Around the world, there were about 806 million cars and light trucks on the road in 2007, consuming over 980 billion litres (980,000,000 m3) of gasoline and diesel fuel yearly.7 The automobile is a primary mode of transportation for many developed economies. The Detroit branch of Boston Consulting Group predicts that, by 2014, one-third of world demand will be in the four BRIC markets (Brazil, Russia, India and China). Meanwhile, in the developed countries, the automotive industry has slowed down.8 It is also expected that this trend will continue, especially as the younger generations of people (in highly urbanized countries) no longer want to own a car anymore, and prefer other modes of transport.9 Other potentially powerful automotive markets are Iran and Indonesia.10 Emerging auto markets already buy more cars than established markets. According to a J.D. Power study, emerging markets accounted for 51 percent of the global light-vehicle sales in 2010. The study, performed in 2010 expected this trend to accelerate.1112 However, more recent reports (2012) confirmed the opposite; namely that the automotive industry was slowing down even in BRIC countries.8 In the United States, vehicle sales peaked in 2000, at 17.8 million units.13
Źródło: https://en.wikipedia.org/wiki/Automotive_industry#Economy
Cars and costs - from Wikipedia
In countries deprived from wide door-to-door public transport and with low density, such as Australia, the automobile plays an important role on the mobility of citizens. Public transport, by comparison, becomes increasingly uneconomic with lower population densities. Hence cars tend to dominate in rural and suburban environments with public economic gains.
The automobile industry, mainly in the beginning of the 20th century when the high motorization rates were not an issue, had also an important public role, which was the creation of jobs. In 1907, 45,000 cars were produced in The United States, but 28 years later in 1935 3,971,000 were produced, nearly 100 times as many. This increase in production required a large, new work force. In 1913 13,623 people worked at Ford Motor Company, but by 1915 18,028 people worked there.10 Bradford DeLong, author of The Roaring Twenties, tells us that, "Many more lined up outside the Ford factory for chances to work at what appeared to them to be (and, for those who did not mind the pace of the assembly line much, was) an incredible boondoggle of a job.10" There was a surge in the need for workers at big, new high-technology companies such as Ford. Employment largely increased.
Źródło: https://en.wikipedia.org/wiki/Economics_of_car_use
Some SI engines are crankcase scavenged
Crankcase scavenged
Diagram of a crankcase scavenged 2-stroke engine in operation
Some SI engines are crankcase scavenged and do not use poppet valves. Instead the crankcase and the part of the cylinder below the piston is used as a pump. The intake port is connected to the crankcase through a reed valve or a rotary disk valve driven by the engine. For each cylinder a transfer port connects in one end to the crankcase and in the other end to the cylinder wall. The exhaust port is connected directly to the cylinder wall. The transfer and exhaust port are opened and closed by the piston. The reed valve opens when the crankcase pressure is slightly below intake pressure, to let it be filled with a new charge; this happens when the piston is moving upwards. When the piston is moving downwards the pressure in the crankcase increases and the reed valve closes promptly, then the charge in the crankcase is compressed. When the piston is moving upwards, it uncovers the exhaust port and the transfer port and the higher pressure of the charge in the crankcase makes it enter the cylinder through the transfer port, blowing the exhaust gases. Lubrication is accomplished by adding 2-stroke oil to the fuel in small ratios. Petroil refers to the mix of gasoline with the aforesaid oil. This kind of 2-stroke engines has a lower efficiency than comparable 4-strokes engines and release a more polluting exhaust gases for the following conditions:
They use a total-loss lubrication system: all the lubricating oil is eventually burned along with the fuel.
There are conflicting requirements for scavenging: On one side, enough fresh charge needs to be introduced in each cycle to displace almost all the combustion gases but introducing too much of it means that a part of it gets in the exhaust.
They must use the transfer port(s) as a carefully designed and placed nozzle so that a gas current is created in a way that it sweeps the whole cylinder before reaching the exhaust port so as to expel the combustion gases, but minimize the amount of charge exhausted. 4-stroke engines have the benefit of forcibly expelling almost all of the combustion gases because during exhaust the combustion chamber is reduced to its minimum volume. In crankcase scavenged 2-stroke engines, exhaust and intake are performed mostly simultaneously and with the combustion chamber at its maximum volume.
The main advantage of 2-stroke engines of this type is mechanical simplicity and a higher power-to-weight ratio than their 4-stroke counterparts. Despite having twice as many power strokes per cycle, less than twice the power of a comparable 4-stroke engine is attainable in practice.
In the USA two stroke motorcycle and automobile engines were banned due to the pollution, although many thousands of lawn maintenance engines are in use.citation needed
Źródło: https://en.wikipedia.org/wiki/Internal_combustion_engine