Engine for motorcycle

Abstract

The invention provides an engine for a motorcycle. For the engine, the diameter of a gas inlet of a cylinder head is 21 to 23millimeters, and the diameter of a gas outlet is 19 to 21 millimeters; the eccentricities of left and right cranks are 30.5 to 32.5 millimeters, and the centre distances of mounting holes on both ends of a connecting rod are 104.5 to 105.5 millimeters; the height of a cylinder body is 75.5 to 77.5 millimeters, the internal diameter of a cylinder sleeve is 54 to 56 millimeters, and the height of the cylinder sleeve is 101 to 103 millimeters; the diameter of an upper end opening of a gas inlet tube is 24 to 26 millimeters, and the diameter of a lower end opening of the gas inlet tube is 21 to 23 millimeters; and the length of a convex hull of a rotor of a magnetic motor is 13 to 18 millimeters, and the included angle between the center of the convex hull and a keyway of the rotor of the magnetic motor is 50 to 60 degrees. The engine has the advantages of effectively improving gas-intake efficiency of the engine, increasing an operating stroke of the engine, reducing rotating speeds of the cranks in all strokes and the rotating speed section of the maximum torque point of the engine, ensuring that the engine can output big torques at the middle / low rotating speed and improving reliability and durability of the engine.

Description

technical field [0001] The invention relates to an internal combustion engine, in particular to an engine used by a three-wheeled motorcycle. Background technique [0002] At present, the working conditions of three-wheeled motorcycles with a displacement of 125ml and above in the domestic market are harsh. Three-wheeled motorcycles are mostly used under heavy loads and poor road conditions, and their engines are mostly used at medium / low speeds. The design concept of the high-speed engine is still used in the design of important parts such as the cylinder head, cylinder block, piston, crank-connecting rod mechanism, intake pipe, valve mechanism, ignition system and transmission system of the traditional three-wheeled motorcycle engine. : [0003] 1. The intake and exhaust passages of the engine cylinder head use a large passage structure (the diameters of the intake and exhaust ports are 28-30mm and 23-25mm respectively) to increase the intake and exhaust volume at high en...

AI Technical Summary

Problems solved by technology

This structural design increases the power and torque loss of the engine at medium / low speed, and at the same time, due to the large spring force, the return impact of the intake and exhaust valves is relatively large, and the noise is relatively increased

[0006] 4. The profile design of the gas distribution cam is relatively steep, the opening and closing time of the valve is short, and the intake advance angle in the gas distribution phase is generally 10°, which cannot meet the requirements of the intake air volume in the low-speed section of the long-stroke engine; at the same time, in order to meet the The force balance of the rocker arm of the short-stroke engine and the best valve opening angle, and the length of the push rod is also short

[0007] 5. The inner diameter of the cylinder liner of the cylinder block is relatively large, reaching 62mm

The tooth thickness designed in this way is relatively small, and the strength and durability of the transmission gear are relatively poor, which is not suitable for the low-speed and heavy-duty use characteristics of tricycles.

[0010] 8. The rotor timing angle of the magneto is relatively large. The length of the convex hull of the magneto is generally about 20mm, and the angle between the center of the convex hull and the center of the magneto is relatively large. The design of the larger timing angle is to ensure accurate and reliable ignition of the engine at high speed. Matches the performance needs of high-revving engines, but is not suitable for three-wheeled motorcycles that use lower revs

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