Knowledge Hall: Car glossary-body parameters

As a modern means of transportation, automobiles are inseparable from people's daily lives. With the increasing popularity of automobiles in daily life, people are eager to understand the relevant professional knowledge of automobiles. Today, let's start with an easy-to-understand explanation of the car body parameters below.

● Long x wide X high

As the name suggests, the so-called length, width, and height are the exterior dimensions of an automobile. The unit is usually mm. The specific measurement method is as follows:

The length of the vehicle body is defined as the distance between two extreme points in the car's length direction, that is, from the maximum protruding position of the vehicle's front bumper to the biggest protruding position of the rear bumper, the distance between the two points.

The vehicle body width is defined as the distance between two extreme points in the automobile width direction, that is, the distance between the left and right most protruding positions of the vehicle body. According to industry rules, the width of the body does not include the width of the left and right rear view mirrors extending out, that is, the width of the rear view mirrors folded.

The body height is defined as the distance from the ground to the highest point of the car. The so-called highest point, that is, the highest position on the top of the body, but does not include the length of the roof antenna.

● Wheelbase

In short, the wheelbase of a car is the distance between the center points of the two adjacent wheels on the same side. That is, the distance from the center point of the front wheel to the center point of the rear wheel is the distance between the front axle and the rear axle, the Axis in mm ).

◆ Automobile Classification Based on wheelbase

The wheelbase is the most important parameter for reflecting the interior space of an automobile. According to the wheelbase size, internationally used cars are divided into the following categories:

Mini Car:

Generally, a model with a wheelbase less than 2400mm is called a mini-car, for example, Chery qq3, Changan Benben, and Geely pandatv. These cars have a wheelbase of about 2340mm and smaller ones include Smart fortwo, the wheelbase is only 1867mm.

Small car:

Generally, a car with a wheelbase between 2550mm-is called a small car, such as Honda Fit, Toyota Vichi, and Ford Fiesta.

Compact car:

Generally, a model with a axis distance between 2700mm-is called a compact car. This type of car is a mainstream model of a household car, such as Volkswagen sagitarta, Toyota Karla, Ford forks, and Honda Civic.

Medium-sized vehicles:

Generally, a model with a wheelbase between 2850mm-is called a medium-sized vehicle. This type of vehicle is usually used both for household and business use, such as Honda Accord, Toyota Camry, Volkswagen magt, and Mazda 6 ruiyi.

Medium and large vehicles:

It usually refers to a model with a wheelbase between 3000mm-. It is called a medium-and large-sized vehicle. This type of model is usually the mainstream model of commercial vehicles, such as Audi A6, BMW 5 Series, Mercedes-Benz E class, and Volvo S80. It should be noted that the wheelbase of medium and large vehicles is usually around 2900mm. However, because Chinese people prefer big cars, many models have been extended to China, and the wheelbase has reached more than 2950mm, the wheelbase of some models has reached more than 3000mm. For example, the wheelbase of the BMW 5 series is 3028mm. So in China, it is very difficult for us to see medium and large cars that will not be extended.

Luxury car:

Generally, a model with a wheelbase of more than 3000mm is called a luxury car. This type of car is usually the model selected by richest people, and the price is basically more than one million yuan. For example: mercedes-Benz S-class, BMW 7 series, and Audi A8. There is also a small group in the category of luxury cars, which we may call as ultra-luxury cars. Their wheelbase is usually above 3300mm, the price is hundreds or even tens of millions, and the number is scarce, there are three main brands: Rolls-Royce, Bentley and Maybach.

Finally, we need to explain to you that, according to the characteristics of models in various countries, the wheelbase of models of the same type is generally small, while that of models of the American brand is relatively large, japanese and Korean cars are intermediate.

● Front wheel distance/rear wheel distance

The wheel distance is divided into the front wheel distance and the rear wheel distance, and the distance between the center of the left and right wheels, usually in millimeters (mm ), the wide wheel distance provides better horizontal stability and better control performance.

The wider the wheels are, the better stability is. Therefore, the wheel distance of an off-road vehicle is wider than that of a General car.

● Minimum ground distance

The minimum ground distance of a car is the distance between the lowest point of the car chassis and the ground on the horizontal plane. The unit is usually mm. The ground distance between different models is also different. The larger the ground distance, the better the vehicle passing ability. Therefore, the ground clearance of an off-road vehicle is usually larger than that of a car.

● Wind resistance coefficient

Air resistance is the biggest and most important external force when a car is driving. The air resistance coefficient, also known as the wind resistance coefficient, is an important factor for calculating the air resistance of vehicles.

The wind resistance coefficient can be measured through a wind tunnel. When a vehicle is tested in a wind tunnel, the vehicle speed is simulated by the wind speed, and the test instrument is used to determine how much power the vehicle needs to withstand the wind speed, this prevents the car from being pushed back. After the required force is measured, the friction between the wheel and the ground is deducted, and the rest is the wind resistance. Then the so-called wind resistance coefficient can be calculated using the aerodynamic formula.

Wind resistance coefficient = front wind resistance × 2 Gb/s (air density × front projection area × speed square ).

The wind resistance coefficient of a vehicle is fixed. The resistance of the vehicle at various speeds can be calculated based on the wind resistance coefficient.

Generally, the vehicle's wind resistance coefficient is between 0.25-0.4. The smaller the coefficient, the smaller the wind resistance.

● Minimum turning diameter

The turning diameter refers to the trajectory circle diameter of the external steering wheel. It refers to the center plane of the vehicle's external steering wheel on the vehicle's bearing plane (generally the ground, that is to say, when the front wheel is driving at the maximum corner, the diameter of the track formed on the ground from the farthest tire surface center in the steering center of the car, usually measured in meters (m ). The minimum turning diameter is a parameter that indicates the flexible turning performance of a car. The left and right turning diameters are different because the extreme turning angles of the steering wheel are generally different.

To put it bluntly, the steering wheel of a vehicle is filled in a certain direction, and the driving vehicle turns into a circle. The diameter of this circle is the minimum turning diameter of the vehicle.

● Empty car Quality

The empty car quality refers to the complete equipment (such as spare tires, tools, etc.) of the automobile according to the factory technical conditions. The quality of all kinds of oil and water after being filled is usually measured in kg ).

● Acceptable Total Quality

The total allowable Quality refers to the total allowable quality of manned vehicles (including drivers) and carrying objects when a car is ready to drive under normal conditions. The unit is usually kg ).

The total allowable quality minus the empty vehicle quality is the maximum carrying quality of the vehicle, that is, the maximum carrying quality of the car.

● Number of doors

The number of doors refers to the total number of doors on the car body including the trunk door. This parameter can be used as a sign for automobile purposes. Ordinary Sedan Cars generally have four doors. Many sports cars have two doors, and each luxury car has six doors. The average hatchback cars, SUV, and MPV are all five doors (the backdoors are lifted), and some sports hatchback cars are designed for three doors.

● Number of seats

The number of seats refers to the seats in the CAR including the driver. Generally, the car has five seats: the front seat is two independent chairs, and the back seat is generally a long chair.

In some luxury cars, there are two separate chairs in the back, so there are four seats.

Some sports cars only have front seats, so they are two seats.

Commercial vehicles and some off-road vehicles are equipped with the third row of seats, so there are six or seven seats.

● Luggage volume

A suitcase is also called a trunk. The volume of a suitcase is used to measure the capacity of a car carrying luggage or other spare items. The unit is generally L ).

According to the vehicle model size and their respective outstanding features, the luggage volume is also different. Generally, the larger the car, the larger the luggage. SUV and business car luggage are relatively large, while some sports car luggage is relatively small due to the design reasons.

● Tank volume

The tank volume refers to the volume of fuel that a vehicle can carry, usually measured in L ). The general tank volume has a direct relationship with the fuel consumption of the car. Generally, a car can drive more than 500 kilometers in a box of oil. For example, the tank volume of A-kilometer 10-litre car is about 60 liters! The tank volume of each model is different, and the tank volume of different brands of similar models is also different. This is determined by the manufacturers.

● Pre-and post-configuration (front/back)

The ratio of the weight of the front axle and the rear axle of the vehicle body. Car weight distribution, generally at 50: 50 is the most average, BMW is the most proud of the 50: 50 before and after weight ratio.

But in real life, we often encounter bending, acceleration, and other situations. From the mechanical point of view, 48: 53 ~ When the distance is between 40 and 60, it will be more flexible to deal with the acceleration of the curve, but the slope is almost the same. On the contrary, the current is more important than the next time, it will be very slow.

● Approximate angle

Approach angle refers to the angle between the tangent of the forward wheel and the ground at the front-end of the vehicle when the vehicle is at rest at full load. That is, the maximum angle between the horizontal plane and the plane that is cut at the outer margin (static load) of the front wheel tire, usually measured in degrees ), any rigid part above the front axle that is fixed on the vehicle shall not be below this plane.

● Departure corner

The exit angle refers to the angle between the tangent of the backward wheel and the road surface when the vehicle is at full load static, that is, the horizontal plane and the outer rim of the vehicle's last wheel tire (static load) the maximum angle between the planes, usually measured in degrees (° ). Any rigid part located behind the last wheel on the vehicle shall not be placed below this plane. It represents the ability of cars to leave obstacles (such as Xiaoqiu and gully land) without collision. The larger the exit angle, the better the passing ability of the car.

● Pass Angle

The pass angle refers to the angle formed when the vehicle is at no-load or at rest, and is submitted to the lower part of the vehicle body through the tangent of the outer rim of the front and back wheels, usually measured in degrees ).

Close to the angle 40 °, exit angle 37 °, through the angle 25 °

● Climbing Angle

When a vehicle is fully loaded, the climbing angle is the maximum slope that is overcome by the first gear on a good road surface. It represents the climbing capability of the vehicle. The slope is expressed by the angle value of the slope (expressed in degrees) or the percentage of the ratio of the height difference between the start and end points of the slope and the horizontal distance (tangent value, the percentage is usually expressed as (% ).

● Maximum wading depth

The maximum wading depth refers to the deepest waters that cars can pass, and is also the safety depth, usually measured in millimeters (mm). This is one of the important indicators to evaluate the cross-country vehicle passing ability.