Basic knowledge of motorcycle engine
The power unit of motorcycle is internal combustion engine. People used to call the engine that uses diesel as fuel a diesel engine, while the engine that uses gasoline as fuel is a gasoline engine. Because gasoline engine has the advantages of light weight, small volume, low noise, low vibration, easy starting and low cost, motorcycles generally use gasoline engine as their power unit
The motorcycle engine is a machine that ignites the fuel mixture entering the cylinder to convert the heat energy generated by combustion into mechanical energy, and transmits the power to the rear wheels of the motorcycle through the transmission mechanism through the crankshaft to become the driving power of the vehicle.
◆ the engine can be a two stroke engine or a four stroke engine.
Two stroke engine: an engine in which the piston reciprocates two strokes up and down to complete a working cycle for each revolution of the engine crankshaft.
Four stroke engine: an engine in which the piston reciprocates up and down for four strokes to complete a working cycle every two revolutions of the engine crankshaft.
The working cycle refers to the working process of the engine consisting of intake, compression, combustion expansion (work) and exhaust stroke. The process of the engine completing one intake, compression, work and exhaust is called a working cycle, also known as a cycle.
1. Explanation of several main terms
A. Top dead center: the piston is connected with the crank connecting rod assembly. The piston has two upper and lower limit positions in the cylinder. The upper limit position is called top dead center, and the distance between it and the crankshaft centerline is the maximum. The lower limit position is called bottom dead center, and its distance from the center line of the crankshaft is the minimum.
B. Piston stroke: the distance that the piston moves from top dead center to bottom dead center is called stroke, also known as stroke.
C. Cylinder working volume: the space swept by the piston in the cylinder for one stroke.
D. Working volume of combustion chamber: the space formed by the top of the piston and the top of the central combustion chamber of the cylinder head when the piston is at the top dead center.
E. Total cylinder volume: sum of cylinder working volume and combustion chamber working volume.