From what aspects is the performance of a car judged?

Main performance indexes of automobile

1, dynamic

The dynamic performance of a car can be evaluated by three indicators: maximum speed, acceleration ability and climbing ability.

(1) The maximum speed of a car refers to the speed that can be achieved on a straight good road (cement road, asphalt road) when the car is fully loaded.

Maximum driving speed.

(2) the acceleration ability of the car-refers to the ability of the car to quickly improve the speed while driving. The acceleration ability of a car is often evaluated by starting acceleration and overtaking acceleration.

(3) The climbing ability of a car refers to the maximum slope that the car can crawl at the lowest gear on a good road when it is fully loaded (30% for trucks, that is, 16.50). The off-road vehicle is 60%, which is about 300).

2. Fuel economy-the ability of a car to complete unit transportation work with minimum fuel consumption under certain conditions of use.

(1)L/ 100km- adopted in China and Europe. The more cars with the same displacement, the worse the fuel economy.

② Mile/US gallon-adopted in the United States. The more cars with the same displacement, the better the fuel economy.

(3)L/ 100t？ Km- truck adoption. The smaller the number of vehicles with different load weights, the better the fuel economy.

3. Braking performance

The braking performance of automobile is mainly evaluated from three aspects: braking efficiency, braking thermal decay resistance and directional stability of automobile during braking.

(1) Braking efficiency-refers to the ability of a car to slow down quickly until it stops.

Braking efficiency is the most basic evaluation index of braking performance, which is evaluated by braking distance, braking deceleration and braking time at a certain initial speed.

(2) Braking thermal decay resistance-refers to the thermal stability of braking efficiency when the automobile is braked at high speed, repeatedly for a short time or continuously on a long slope.

(3) The directional stability of the vehicle when braking refers to the ability of the vehicle to follow the prescribed trajectory when braking, that is, the ability not to deviate, sideslip or lose steering.

Usually, a test channel with a certain width is specified, and cars with good braking stability are not allowed to deviate from this channel due to uncontrollable efficiency during the test.

4. Handling stability

Vehicle handling stability contains two interrelated contents, one is maneuverability and the other is stability. Stability refers to the ability of a car to recover its normal driving state and direction as soon as possible after being disturbed by the outside (road surface disturbance or sudden gust disturbance), without losing control, and to resist overturning and sideslip.

5, ride comfort

When a car is running, the vibration isolation characteristics of road roughness are called car ride comfort.

When the road roughness reaches a certain level, passengers will feel uncomfortable and tired, or the goods they carry will be damaged. The additional dynamic load caused by vibration caused by road roughness will accelerate the wear of related parts and shorten the service life of the car. The fluctuation of wheel load will affect the adhesion between the wheel and the ground, which is related to the handling stability of the car.

The vibration of the car increases with the increase of driving speed. In the process of car use, the driving speed is often limited by the strong vibration of the car body.

6. Discharge pollutants

There are three main sources of automobile emission pollution: one is the exhaust gas discharged from the engine exhaust pipe after fuel combustion; Second, crankcase emissions; The third is fuel evaporative emissions.

China's pollutant emission control objectives for light vehicles, heavy vehicles, motorcycles and other vehicles are:

From 2000 to 2006, 5438+0 reached Euro I (that is, China's first-stage control target); In 2004 ~ 2005, it reached Euro II (the second-stage control target of China); Strive to be in line with the international emission control level around 20 10.

7. Noise

According to the process of noise generation, automobile noise sources can be roughly divided into: sound sources related to engine speed and sound sources related to vehicle speed.