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The basic principles of motor cars

In order to allow everyone in our Pacific Automotive Network to learn more and more systematic knowledge of the car, so you automotive enthusiasts, whether watching or playing car car, car of the process to be in this area ” experts “, we will continuously launch” car knowledge, easy entry “series of topics in order to bring you period will get to know in simple terms the principle and automotive parts of structure.

First, the basic principles of motor cars

  We know the car is to exercise, there must be the driving force to overcome resistance, that is, the car is moving in the required power and energy is determined by its driving resistance.

  Therefore, we first have to understand is the resistance. Some people probably asked, as long as a car, we installed a powerful engine like, and also need it to hell What resistance? If so, would face several problems: 1, how much power the engine now? No comparative reference, how do we determine what we need more power; 2, car design is the first car assembly design, such as chassis, body parts, etc. only after the design and selection engine, if you do not know This car will face resistance, we simply can not design a practical car; 3, even with a very powerful engine (enough to inform any resistance on the ground when traveling), and have installed the appropriate vehicle body will be in use because the ride, fuel consumption, emissions, maintenance, repair, etc. that you can not properly use it. Thus, we have to understand the car power, first of all is to know what obstacles we encountered.

  general, automobile driving resistance can be divided into stable dynamic driving resistance and driving resistance.

  stability of resistance, including the wheel driving resistance, air resistance and the slope resistance.

  1, the wheel resistance

  what we call the wheel of resistance is the tire rolling resistance, tire slip road there is resistance to the resistance caused by the composition.

  When the car is moving will make the tire deformation, rather than round when kept stationary, and since the rubber and tire itself has flexibility within the air, so tires will make the tire rolling through compression and stretch repeatedly process, the resulting damping function, that is, deformation resistance. After tests showed that when the car more than 45m / s (162km / h) when the tire deformation resistance will dramatically increase, which requires not only a higher power, on the tire itself is a great test. The tires on the road, the tread and the ground exists between the local vertical and horizontal relative sliding, there will be a wheel bearing internal relative motion, so it will generate friction. Since we are surrounded by air, as long as movement of objects would be air resistance. The three resistance: deformation resistance, friction of air resistance are the sum of the tire is a tire’s rolling resistance. At 40m / s (144km / h) speed of the following within the deformation resistance of the tire rolling resistance accounts for 90% -95%, 2% -10%, friction, and tire very small percentage of air resistance.

 The surface resistance of the tire in a variety of road surfaces is the rolling resistance of a variety of different roads, and the formation of resistance are different, not studied in detail here. There is the tire cornering due to resistance, which is due to the movement direction of the wheel lateral force generated by the angle generated.

  2, air resistance

  car is moving, the need to squeeze open the air around the car in front formed by the air pressure and vacuum, resulting in pressure difference, there are also layers of air and air between the friction with the car, plus cooling the engine, the surface of convex indoor ventilation and automotive parts due to air interference, air resistance is formed. It includes a pressure drag (also known as the shape of the resistance), induced resistance, that resistance (or friction), internal resistance (also called inner loop resistance), and interference resistance of the composition. Air resistance and the shape of the car, the car’s front projection area, in particular with the car – the air is proportional to the square of the relative velocity. When the car at high speed, air resistance values will increase significantly. We often appear in the car’s drag indicator is the calculation of air resistance air resistance coefficient. The coefficient is small as possible.

  3, slope resistance

  when the car uphill, along the plane direction of the total weight of the component of the formation of resistance.

  dynamic driving resistance, the main force is the inertia, and it includes the inertia caused by translation quality, but also caused by rotating mass moment of inertia.

  We now know that car to be able to exercise together must overcome the above description of the total resistance, as resistance increases, car drivers must also be followed to increase, and resistance to a range of balance, we know that driving force of the largest value depends on the maximum engine torque and power train transmission ratio, but the real driving force has been issued between tire and road adhesion properties (including the various conditions of road conditions) limit. Only in general terms of car restrictions on these various factors with the balanced, smooth movement up and can become the tools we need.

  above we have a basic understanding of the basic principles of motor cars. Topic in the future, we will further the structure of cars, really begin to understand car.