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
Alcohol and driving is
Driving after drinking can be dangerous even when guided bike. In the case of more complex machines, allowing to achieve a much higher speed, directing them under the influence of alcohol can be fatal. Despite the many social campaigns regarding the prohibition of driving under the influence of alcohol and strengthen penalties for drunk drivers, unfortunately, many of them still do not apply to this rule. Meanwhile, the management of a car under the influence of alcohol can lead to death of not only the driver and passengers, but also to the disappearance of completely innocent people, not even staying on the road during this event. Getting into the car under the influence of alcohol we create unnecessary risk.
Why do some cars can afford only the richest?
Luxury car brand virtually since their inception are surrounded with an aura of mystery for average earners. Although over the years the exclusive, global brand cars were beginning to reveal its secrets to the outside world and show their offer, however, to this day, some car models are intended only for the richest people in the world. Luxury cars are a sign of prestige and good luck, while allowing very stand out in the crowd. Most of them are made of special materials and to achieve a surprisingly high speed. Another advantage of these cars is equipped with many different, sometimes very expensive gadgets.