What is the working principle of motorcycle engine?

Motorcycle engine \ x0d \ x0d \ The working principle of motorcycle engine is the same as that of automobile engine. The engine consists of a piston, a cylinder block and a cylinder head, and the cylinder head contains a valve mechanism. When the spark ignites the mixture of fuel and air, it will cause an explosion and push the piston to move up and down in the cylinder block. Then the valve is opened and closed, so that the mixture of fuel and air enters the combustion chamber. The up-and-down motion of the piston drives the crankshaft to rotate, and the energy of the piston is converted into rotary motion. The rotating force of the crankshaft is transmitted to the rear wheel of the motorcycle through the transmission. \ x0d \ x0d \ cylinders \ x0d \ x0d \ motorcycles can have 1-6 cylinders. For many years, V-twin design has been the choice of motorcycle engineers in America, Europe and Japan. V-twin is named after a V-shape with two cylinders, such as the classic Harley-Davidson V-twin engine shown below. Harley-Davidson V-twin pays attention to 45 degrees, and other manufacturers can change this angle to reduce vibration. \x0d\\x0d\V-twin is just a way to arrange two cylinders. If the pistons are facing each other, the anti-double-row design should be selected when the cylinders are discharged. The parallel two-cylinder engine places the pistons vertically side by side. \x0d\\x0d\ At present, the most popular design is four cylinders. This design runs more smoothly and rotates faster than a two-cylinder engine. Four cylinders can be placed side by side or arranged in a V shape, with two cylinders on each side of the V shape. \x0d\\x0d\ capacity \x0d\\x0d\ The size of the combustion chamber of motorcycle engine is directly related to its output power. The upper limit is about 1500cc (cubic centimeter) and the lower limit is about 50cc. The latter engine is usually used for scooters (motor bicycles), and its fuel consumption is 100 km 2.35 liters, and the fastest speed can only reach 48-56 km/h. \ x0d \ x0d \ gear set \ x0d \ x0d \ gear set is a set of gears that can make the motorcycle stop completely to reach cruising speed. The transmission on motorcycles usually has 4-6 gears. However, there may only be two scooters. By engaging the gear with the shift lever, the shift fork can move in the transmission. \ x0d \ x0d \ clutch \ x0d \ x0d \ The function of the clutch is to engage and disconnect the power transmitted by the engine crankshaft to the transmission. If there is no clutch, the only way to stop the wheel rotation is to turn off the engine, which is impractical in any type of motor vehicle. A clutch is a series of spring-loaded plates that, when pressed together, connect the transmission to the crankshaft. When shifting gears, the motorcycle hand disconnects the transmission from the crankshaft with the clutch. Once a new gear is selected, re-establish the connection using the clutch. \x0d\\x0d\ transmission system \x0d\\x0d\ can transmit engine power to motorcycle rear wheels in three basic ways: chain, belt or shaft. Chain main reducer system is the most commonly used way at present. In this system, the sprocket installed on the output shaft (that is, the shaft in the transmission) is connected to the sprocket attached to the rear wheel of the motorcycle through a metal chain. When the transmission rotates the smaller front sprocket, it transmits power to the larger rear sprocket along the chain, and then rotates the rear wheel. This system must be lubricated and adjusted, and it needs to be replaced regularly due to chain elongation and sprocket wear. \ x0d \ x0d \ belt drive is a substitute for chain drive. Early motorcycles often used belts, which can be tensioned by spring-loaded pulleys and handles to provide traction. The belt is easy to slip, especially in wet weather, so this method is often not adopted, and other materials and designs are used instead. At the end of 1980s, the development of materials made the belt main reducer system possible. Now, the belt is made of toothed rubber, which works like a metal chain. Unlike metal chains, belts do not need lubrication or cleaning agents. \x0d\\x0d\ sometimes shaft final drive is also used. This system transmits power to the rear wheels through the transmission shaft. Shaft drive is very popular because it is very convenient and does not need as much maintenance as chain system. However, the shaft transmission is heavy, which sometimes leads to unnecessary vibration at the tail of motorcycle, which is called jacking shaft. \x0d\x0d\ motorcycle chassis \ x0d \ seats and accessories \ x0d \ the seats on motorcycles are designed to carry one or two passengers. The seat is located behind the fuel tank and can be easily removed from the motorcycle frame. Some seats have small cargo compartments under or behind them. If you need more storage space and saddle bags, you can install hard plastic boxes or suitcases on both sides of the rear wheel or on the tailgate. Large motorcycles can even tow small trailers or sidecars. The sidecar is supported by its own wheels, and an extra seat can accommodate one passenger. \ x0d \ x0d \ Motorcycle chassis consists of frame, suspension device, wheels and brakes. Each component will be briefly described below. \ x0d \ x0d \ frame \ x0d \ x0d \ motorcycle frame is made of steel, aluminum or alloy. Automobile frames are mostly composed of hollow tubes, which are used as the skeleton for installing components such as transmission and engine. The frame also keeps the wheels in a straight line to control the motorcycle. \ x0d \ x0d \ suspension \ x0d \ x0d \ The frame is also the support of the suspension system. The suspension is a set of springs and shock absorbers, which helps to keep the wheels in contact with the road and form a buffer for bumps and bumps. Swing arm design is the most common solution of rear suspension device. At one end, the swing arm controls the rear axle. At the other end, it is connected to the frame by a rocker pivot bolt. The shock absorber extends upward from the pivot bolt of the rocker arm and is connected to the top of the frame directly under the seat. The front wheel and axle are mounted on the telescopic fork with internal shock absorbers and internal or external springs. \ x0d \ x0d \ wheels \ x0d \ x0d \ Although some models introduced in 1970s provided cast steel wheels, motorcycle wheels usually use aluminum wheels or steel wheels with spokes. Cast steel wheels allow motorcycles to use tubeless tires, that is, it has no inner tube to keep compressed air, which is different from traditional pneumatic tires. Air is maintained between the rim and the tire, and the internal air pressure is maintained according to the sealed space formed between the rim and the tire. \ x0d \ x0d \ tubeless tires are less prone to burst than tubed tires, but there may be problems on rough roads due to small rim bending. Tires of various designs can meet the requirements of different terrain and driving conditions. For example, motorcycle tires on dirt roads have deep multi-segment treads to form the maximum grip on dust or particles. Travel motorcycle tires are made of hard rubber, which usually provides less grip but longer life. Although the contact area with the road surface is small, sports and competition tires (usually radial tires with steel belts) can provide amazing grip. \x0d\\x0d\ Brake \x0d\\x0d\ Motorcycles have brakes at the front and rear wheels. Motorcyclists use the handle on the right handlebar to start the front brake, and use the right pedal to start the rear brake. Drum brakes were widely used in 1970s, but at present, most motorcycles use disc brakes. The disc brake consists of a steel brake disc, which is connected to the interlayer between the wheel and the brake pad. When the motorcyclist operates the brake, the hydraulic pressure controlled by the brake pipe makes the brake pad squeeze both sides of the brake disc. Friction causes the brake disc and the connected wheel to slow down or stop. Because repeated use will wear its surface, the brake pads must be replaced regularly.