reduce smoke Triumph There are cast in ducts from the crankcase
Historical design
Dugald Clerk developed the first two cycle engine in 1879. It used a separate cylinder which functioned as a pump in order to transfer the fuel mixture to the cylinder.6
In 1899 John Day simplified Clerk's design into the type of 2 cycle engine that is very widely used today.13 Day cycle engines are crankcase scavenged and port timed. The crankcase and the part of the cylinder below the exhaust port is used as a pump. The operation of the Day cycle engine begins when the crankshaft is turned so that the piston moves from BDC upward (toward the head) creating a vacuum in the crankcase/cylinder area. The carburetor then feeds the fuel mixture into the crankcase through a reed valve or a rotary disk valve (driven by the engine). There are cast in ducts from the crankcase to the port in the cylinder to provide for intake and another from the exhausst port to the exhaust pipe. The height of the port in relationship to the length of the cylinder is called the "port timing."
On the first upstroke of the engine there would be no fuel inducted into the cylinder as the crankcase was empty. On the downstroke the piston now compresses the fuel mix, which has lubricated the piston in the cylinder and the bearings due to the fuel mix having oil added to it. As the piston moves downward is first uncovers the exhaust, but on the first stroke there is no burnt fuel to exhaust. As the piston moves downward further, it uncovers the intake port which has a duct that runs to the crankcase. Since the fuel mix in the crankcase is under pressure the mix moves through the duct and into the cylinder.
Because there is no obstruction in the cylinder of the fuel to move directly out of the exhaust port prior to the piston rising far enough to close the port, early engines used a high domed piston to slow down the flow of fuel. Later the fuel was "resonated" back into the cylinder using an expansion chamber design. When the piston rose close to TDC a spark ignites the fuel. As the piston is driven downward with power it first uncovers the exhaust port where the burned fuel is expelled under high pressure and then the intake port where the process has been completed and will keep repeating.
Later engines used a type of porting devised by the Deutz company to improve performance. It was called the Schnurle Reverse Flow system. DKW licensed this design for all their motorcycles. Their DKW RT 125 was one of the first motor vehicles to achieve over 100 mpg as a result.14
Źródło: https://en.wikipedia.org/wiki/Internal_combustion_engine
Employment opportunities in the automotive industry
While working in the garage is the most common employment opportunities for people fascinated with the automotive industry, it is certainly not the only option that we can choose where we want to take up employment in this industry. Very interesting, though perhaps sometimes quite tedious task for people interested in the subject is the position of consultant in showrooms respective car brands. You have to admit, however, that in order to obtain employment in a place like this should have appropriate knowledge and skills, especially in dealing with customers. Many options of employment also provides production vehicles of different types or auto parts. Employment in this place very often involves simple tasks.
Car issue - public benefits
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