Body: Body size-length * width * height
Now the unit of body shape data is mm, and thousands of numbers will make people see things in a blur. What is the length, width and height of the car body to be called a cart? Let's analyze it for everyone according to the vehicle level.
In the database, we classify cars into A00 (mini car), A0 (compact car), A (compact car), B (medium car), C (medium car) and D (luxury car). What are the criteria for dividing these levels?
According to the body length:
Minicars under 3.7M (representative models QQ, SPARK, Hafei Lubao, Alto, Minivan).
3.7-4.3M is a small car (representing model 206, Fit, polo and Carnival).
4.3-4.6M is a compact car (representing Focus, Sagitar, Corolla, 307 and Civic).
4.6-4.9M is a medium-sized car (representative models Camry, Magotan, Accord, Zhisheng, Spiro, mercedes benz c, BMW 3 and Audi A4).
4.9-5. 1M is a medium and large car (Mercedes-Benz E, BMW 5, Audi A6).
5./KLOC-luxury cars above 0/m (Mercedes-Benz S, BMW 7, Audi A8).
Based on wheelbase:
Minicars under 2350 mm
2350mm-2500mm compact car
2500mm-2700mm compact car
2700mm-2800mm medium-sized car
2800mm-2900mm medium and large cars
A large luxury car exceeding 2900 mm
Now the vehicles are getting bigger and bigger, and the body size of the same level is getting bigger and bigger. Honda Feng Fan, Peugeot 408, Buick LaCrosse and other leapfrog models emerge one after another. The above data is only a widely accepted reference value, and different models need specific analysis.
Wheelbase (of a vehicle)
The wheelbase is the distance between two vertical lines passing through the midpoint of two adjacent wheels on the same side of the vehicle and perpendicular to the longitudinal symmetry plane of the vehicle. Simply put, it is the distance from the center of the front axle to the center of the rear axle.
After the length of the car is determined, the wheelbase is the most important factor affecting the seating space, because the passenger seats of hatchback and sedan passenger cars are arranged between the front and rear axles. Long wheelbase will increase the longitudinal space of passengers and greatly increase the foot space that affects the ride comfort of vehicles. Although the wheelbase is not the only factor that determines the interior space, it is the fundamental factor.
At the same time, the length of the wheelbase has a great influence on the comfort and handling stability of the car. Generally speaking, the higher the car class, the longer the wheelbase, the longer the carriage length, the more spacious the seat space for passengers, and the better the pitch and yaw resistance. The long wheelbase improves the cruise stability of the straight road, reduces the steering flexibility, increases the turning radius, and the worse the maneuverability of the car. Therefore, we must make a balance between stability and flexibility and find a suitable balance point. In high-end cars with long wheelbase, such shortcomings have been made up by other high-tech devices.
Many foreign models, such as Audi A6L, BMW 5 Series, etc., will extend the wheelbase after being introduced into China to adapt to the China market.
Front/rear track
The distance between the center lines of the tracks left by the front/rear wheels on the vehicle support plane (generally the ground), that is, the distance between the centers of the left front wheel and the right front wheel.
The wheel track size has an influence on the total width, total weight, driving stability, handling and passability of the car. Generally speaking, the larger the track, the better the driving stability, that is, the larger the track, the less likely the vehicle will roll over. Vehicles with wider track can also increase the width of the interior space and shoulder width, making the ride more comfortable. Therefore, the track of some commercial vehicles is generally relatively large. However, the wider the track, the greater the overall width and weight of the car.
Most cars have the same front and rear wheel tracks, but some cars have different front and rear wheel tracks. Generally speaking, there are obvious differences between the front and rear wheel tracks of sports or sports cars. For example, Ferrari 6 12, the front wheel track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track track Ferrari 6 12 has a front tire width of 245 mm and a rear tire width of 284 mm, and the difference between them is inevitable.
Measure the distance from the ground
The minimum ground clearance refers to the distance between the ground and the lowest point of rigid parts at the bottom of the vehicle (such as engine oil pan, oil tank or suspension) after the fully loaded vehicle stops horizontally. The greater the ground clearance, the better the performance of passing through uneven roads. On the contrary, the wind resistance is small and the high-speed stability is good. The minimum ground clearance of general cars is about 1 100 mm, while many sports cars are even lower than 100mm, because the design speed of sports cars is very high. In order to increase the stability of the car body at high speed and reduce the wind resistance, it is necessary to reduce the gap between the car body and the ground. The minimum ground clearance of off-road vehicles and SUV models is large, and the minimum is160 mm.
Generally speaking, the lowest point of the car body is generally below the gearbox or engine oil pan, and the lowest point of off-road vehicles is generally the differential of the front and rear axles.
Minimum turning diameter
The minimum turning diameter turns the steering wheel to the limit, making the car do circular motion, and the center of the outer tread of the steering wheel is a larger track circle diameter on the flat ground. Characterize the ability of a car to pass through a narrow curved area or bypass obstacles. It is directly related to the wheelbase, track distance and steering wheel limit angle of the car. The larger the wheelbase and track, the larger the turning diameter; The greater the limit angle of the steering wheel, the smaller the turning diameter.
Body structure
According to the stress and structure of the car body, it can be divided into bearing type, semi-bearing type, non-bearing type and space frame type.
Body chassis integrated
A car with a load-bearing body has no rigid frame, and the front, side wall, rear end and floor are strengthened. The engine, front and rear suspensions, part of the transmission system and other assembly parts are assembled on the car body, and the load of the car body is transferred to the wheels through the suspension device. Most cars use load-bearing body, which has the advantages of low noise, light weight and relatively fuel saving, but the disadvantage is relatively low strength.
Bearing body 1 structural drawing
Load-bearing body structure Figure 2
Non-carrier
Non-load-bearing body has a rigid frame, also called chassis beam frame. Engine, transmission system, car body and other assembly parts are fixed on the frame, and the frame is connected with wheels through front and rear suspension devices. The advantages are high chassis strength, good anti-bumping performance and difficult deformation of the car body. Non-load-bearing body is large in size and weight, and is generally used for trucks, buses and off-road vehicles.
space frame
ASF (Audi Space Frame) is a lightweight technology developed by Audi, which uses aluminum as the main material and combines with other materials to build the car body. Also known as Audi Space Frame (ASF). This technology has stopped the trend of gaining weight with the continuous improvement of functionality.
Approach angle/departure angle
Approach angle refers to the maximum included angle between the outer edge of the ground and front tires and the bumper plane when the fully loaded vehicle is in a horizontal static state. The bigger the approach angle, the better the passability. Approach angle is rarely mentioned in cars because of its different uses. Approach angle of ordinary cars is around 25, while approach angle of SUV models is above 30.
The bigger the approach angle, the less likely it is to have a "contact" accident, and the better the passing performance of the car.
Deviation angle (of a high-speed moving object deviating from its normal route or orbit)
Departure angle refers to the angle between the tangent line from the convex point at the rear end of the car body to the rear wheel and the road surface, that is, the maximum angle between the horizontal plane and the plane tangent to the tire outer edge (static load) of the last wheel of the car. Any rigid parts fixed to the car behind the last wheel shall not be lower than this plane. Represents the ability of cars to leave obstacles (such as hills, gullies and depressions) without collision. The larger the departure angle, the better the passability of the car.
Compared with approach angle, the departure angle is suitable for uphill. The vehicle goes downhill all the way, and when the front wheel has traveled to the flat ground and the rear wheel is still on the ramp, the larger the departure angle, the vehicle can get down from the steep ramp.
Wind drag coefficient
Wind resistance coefficient is a mathematical parameter determined by wind tunnel experiment and sliding experiment, which is used to calculate the air resistance of automobile. The drag coefficient depends on the shape of the car and is directly proportional to the air resistance, which mainly affects the fuel consumption and shape stability of the car. Generally speaking, the drag coefficient of most cars we see on the road is around 0.30. The drag coefficient of cars with good flow linearity, such as sports cars, can reach below 0.28, and that of racing cars can reach about 0. 15.
The smaller the drag coefficient of a car, the lower the fuel consumption of the car. When the drag coefficient is reduced by 10%, the actual fuel consumption can be reduced by 2.5%.
Wind resistance coefficient = frontal wind resistance × 2÷ (air density × frontal projection area × vehicle speed square).
Maximum wading depth
The maximum wading depth is the maximum water depth for a car to pass safely and trouble-free, and it is one of the important indexes to evaluate the cross-country passability of a car.
Luggage compartment volume
The luggage compartment volume (L) can indicate the carrying capacity of the luggage compartment, which is generally expressed by numerical value or range value, and the unit is liter. The number of items contained in the rear seats of hatchback models before and after being laid down is expressed by the range value. For example, before and after the rear seat of Peugeot 308SW was put down, the luggage compartment volume was 674 liters and 2 149 liters respectively.