However, this does not discourage people who want to manage their own engine.It is true that, during the practical lessons in this category may appear to be much more problematic and dangerous events, but this challenge can be met through a systematic science.
The word "car" is believed to originate from the Latin word carrus or carrum ("wheeled vehicle"), or the Middle English word carre (meaning cart, from Old North French).
In turn, these originated from the Gaulish word karros (a Gallic chariot).The Gaulish language was a branch of the Brythoic language which also used the word Karr; the Brythonig language evolved into Welsh (and Gaelic) where 'Car llusg' (a drag cart or sledge) and 'car rhyfel' (war chariot) still survive.1112 It originally referred to any wheeled horse-drawn vehicle, such as a cart, carriage, or wagon.1314 "Motor car" is attested from 1895, and is the usual formal name for cars in British English.3 "Autocar" is a variant that is also attested from 1895, but that is now considered archaic. It literally means "self-propelled car".15 The term "horseless carriage" was used by some to refer to the first cars at the time that they were being built, and is attested from 1895.16 The word "automobile" is a classical compound derived from the Ancient Greek word autós (?????), meaning "self", and the Latin word mobilis, meaning "movable".
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 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.
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.