Car as a modern means of transport , hasbeen inextricably linked in people's lives today . With the car in everydaylife growing popularity , people understand the car all the relevant expertiseis increasingly urgent desire . Today, we have to explain that we can begin tounderstand the car body parameters described below .

● length × width × height

As the name implies , is a car called thelength and breadth of the dimensions, usually in millimeters (mm), the specificmeasurement method is this:

Body length is defined as : car lengthdistance between the two extremes points , from the front of the car bumpermost protruding position measured from the rear bumper to the car 's mostprotruding position , the distance between these two points .

Body width is defined as: car width directionof the distance between two extreme points , which is the body of the left andright distance between the most projecting position . According to industrygeneral rule, the width of the body does not contain the left and right sidemirrors projecting width , i.e. the width of the folded mirror .

Body height is defined as : from the ground, the highest point of the distance to the car . The so-called highest point,which is the highest position at the top of the body , but does not include thelength of the roof antenna .

● Wheelbase

Simply put , the car's wheelbase is thesame side of the front and rear wheels adjacent to the distance between thecenter point , namely: from the front wheel center to center distance betweenthe rear wheels , the front axle and the rear axle is between distance, shortwheelbase in millimeters (mm).

◆ According to the wheelbase of the car to classify

A car wheelbase is the reaction of the mostimportant parameters of the internal space , according to the size of the wheelbase, the international common cars into the following categories:

Mini cars :

Usually refers to the following modelswheelbase 2400mm called mini cars , for example: Chery QQ3, Changan Benben ,Geely Panda , etc. These are 2340mm wheelbase cars around , there is a smallerSMART FORTWO, wheelbase of only 1867mm.

Small Car :

Usually between 2400-2550mm wheelbasemodels called small cars, such as : Honda Fit , Toyota Vios, Ford Fiesta andother .

Compact car :

Usually between 2550-2700mm wheelbasemodels called compact car , this level models is the mainstream family carmodels, such as : Volkswagen Jetta , Toyota Corolla, Ford Focus , Honda Civic ,etc.

In the car :

Usually between 2700-2850mm wheelbasemodels known in the car , this level models are usually combined household andbusiness models , for example: Honda Accord , Toyota Camry, Volkswagen Magotan, Mazda 6 Rui -wing and so on.

In the large car :

Usually between 2850-3000mm wheelbasemodels known in the large car , this level models are usually commercialvehicles mainstream models , such as : Audi A6, BMW 5 Series , Mercedes-BenzE-Class , Volvo S80 and so on. It should be noted that: usually medium andlarge cars are 2900mm wheelbase around , but because the Chinese people prefercarts , so many models to China have carried out a lengthened wheelbase havereached more than 2950mm , wheelbase reached individual models 3000mm or more,such as the BMW 5 Series wheelbase is 3028mm, so in the country, we no longerdifficult to see into the medium and large car.

Luxury cars :

Usually refers to more than 3000mmwheelbase models known in the luxury car , this level models is usually richselection of models , the prices are more than one million yuan , for example:Mercedes-Benz S-Class , BMW 7 Series , Audi A8 and so on. In the luxury car inthis category, there is a small group, we might call it super- luxury cars ,they are usually in the 3300mm wheelbase than the price moving hundreds or eventens of millions, the number of rare , there are three main brands :Rolls-Royce , Bentley and Maybach .

Finally, there is little need to explain toeveryone , according to the characteristics of each country vehicle , generallythe same type of models, European brands wheelbase is relatively small, whilethe American brand wheelbase is relatively large, Japanese and Korean cars isthe middle level .

● Tread front / rear track

Tread is divided into front track and reartrack , and track and the left and right distance between the wheel center ,usually in millimeters (mm), wider track for better lateral stability andbetter control performance.

Position of the wheels touch the ground themore spacious models, the driving stability as possible, so the track than theaverage SUV car models to be wide.

● The minimum distance from the ground

Minimum ground clearance vehicles , vehiclechassis in the horizontal plane is the lowest point of the pitch with theground , usually in millimeters (mm), different models of its ground clearanceis different, the greater the distance from the ground , the vehicle throughsex on possible. It is usually ground clearance off-road vehicles to be largerthan the sedan .

● drag coefficient

Cars with air resistance is encounteredwhen the largest and most important force. Air resistance , also known as thedrag coefficient is calculated automobile air resistance is an important factor.

Drag coefficient can be measured throughthe tunnel . When the vehicle is tested in the wind tunnel , through the windto simulate a moving vehicle speed , and then to test the equipment to detecthow much power the car needs to resist the wind , so that the car will not bethe wind back. In measured the force required , and then deduct the wheelfriction with the ground , the rest is drag , and then to a formula cancalculate the aerodynamic drag coefficient called .

Drag coefficient = positive wind resistance× 2 ÷ ( air density × front frontal projected area × speed square ) .

A car 's drag coefficient is fixed, thedrag coefficient can be calculated according to the vehicle in a variety ofspeeds the drag .

In general the vehicle drag coefficientbetween 0.25-0.4 , the coefficient is smaller, the smaller the drag .