Air resistance
As we all know, the faster the speed the greater the resistance, air resistance is proportional to the square with car speed. If air resistance accounts for a large vehicle driving resistance ratio will increase vehicle fuel consumption or seriously affect the car's dynamic performance. According to the test, a speed of 100 km per hour driving a car, the engine output power of 80% will be used to overcome air resistance, reduce air resistance, can effectively improve the car's driving the economy, so car designers attach great importance to aerodynamics. In introducing the article on performance cars often of the "drag coefficient" is the aerodynamic terminology, is one of the parameters to measure the performance of modern cars.
Aerodynamic drag coefficient
The car is moving because of the role of air resistance, gravity around the car while producing longitudinal, lateral and vertical direction of the air moving in three forces, high-speed car will have different effects, which is the largest vertical air force air resistance, aerodynamic drag accounts for about 80 percent of the whole over. Its coefficient is obtained from the wind tunnel test out, and the synthesis of car air speed is closely related to the formation of the dynamic pressure. When the body size of the same projection, body shape or body surface treatment of various different air dynamic pressure values ??are different, the air drag coefficient will be different. As the air resistance and air drag coefficient is proportional to the modern cars to reduce air resistance must be considered to reduce air drag coefficient. From the 1950s to the early 1970s, car air drag coefficient remained at between 0.4 to 0.6. 1970s energy crisis, countries in order to further save energy and reduce fuel consumption, are committed to reducing air drag coefficient, and now the car aerodynamic drag coefficient is generally between 0.28 to 0.4.
Car shape design
In order to reduce air drag coefficient, the general shape of the modern car park slide with smooth curves to turn the car body blanking line. Front wall and side panels, front wall, side panels and engine cover, side panels, etc. and after places around are used park slide transition, under the forward tilt hood, short rear cover after Gao Qiao, Ji after the daughter board to the After the contraction, using a large curved glass windshield and roof garden with slide transition, and the horizontal angle between the front windscreen is generally 25 degrees -33 degrees, with flat side with the body, front and rear lamps, door handle embedded in car body, the body as clean smooth surface, the vehicle covered with a flat cover, reduce the vehicle height, etc. These measures will help reduce air drag coefficient. In the early 1980s, the advent of the German Audi 100C sedan is the most prominent example, it uses the above measures, the air drag coefficient of only 0.3, a business on behalf of the cars exterior design was the best example.
According to the tests showed that the air drag coefficient decreasing by 10%, about seven percent fuel savings. It has been on two of the same quality, same size, but with different aerodynamic drag coefficient (0.44 and 0.25, respectively) compared to the car to 88 kilometers per hour, driving 100 km per hour, the latter than the former to save fuel consumption by 1.7 liters.
Study the history of car-shaped car, from the beginning of this century, the Ford T-box-type body to 30 years of beetle-type medium-sized body, beetle-shaped body 50 from the ship's body, from the ship's body into the wedge-shaped body 80, Even today the car body model, the emergence of each body shape, not simply a period of a product of industrial design, but along with the technological advances of modern aerodynamics and development. Air drag coefficient of cars in the past never had the manual, is to introduce the car today is one of the commonly used term, become very concerned about a parameter.
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