How to structure long-term contracts

List of contents of this article:

• 1, How to identify the grade of a car engine
• 2
  、How to distinguish the model of diesel engine
• 3,How to structure long-term contracts How to distinguish second-hand car engines
• 4 , What is the difference between the engine?

How to identify the grade of a car engine

1. Engine: The more cylinders, the higher the grade. In general, according to the size of the displacement, automobile engines can be divided into three-cylinder, four-cylinder, six-cylinder and eight-cylinder.

2. A good engine.. It depends on how it twists.. It is mainly urban walking. If you need a low speed and a high torque, it will ruse as soon as it is fueled. Of course. You can't buy a family car with an elegant appearance... Generally, the weight of the car is directly proportional to the fuel consumption. For example.

3. The issuance of judging the quality of the engine is as follows: The form of the engine determines the grade. In general, according to the displacement size, the engine is divided into three-cylinder, four-cylinder and six-cylinder., eight-cylinder and turbocharged types, while L4 (in-line four-cylinder engine) and V6 (V-type six-cylinder engine) and turbocharged models are more common.

4. The following is the way to judge whether the engine is good or bad: look at the engine speed. Generally speaking, the engine speed between 2500 and 3000 is a more suitable engine speed. In the same case of 120 miles, the more expensive the car, the lower its engine speed may be.

5. Look at the appearance of the engine and identify the traces of oil leakage and water leakage. Check the external cleanliness of the engine to see if there is too much dust to determine whether the wear is too much, but pay special attention to the fact that if it is spotless, it does not mean that the car is worn very little, or it may be that the owner has done something to cover up some information.

How to distinguish the model of diesel engine

According to the provisions of the national standard GB725, the internal combustion engine model is divided into the number of cylinders, stroke type, cylinder arrangement and cylinder diameter. Structural characteristics and use characteristic symbols are composed of distinguishing symbols that change in structure and performance after modification.

The following is a specific introduction to the meaning of the diesel engine model: product replacement code: missing basic type; X new model; B, R replacement logo. Number of cylinders: numbers. Cylinder arrangement form: missing in-line; VV-shaped arrangement. Cylinder diameter: the unit is mm. Enhanced code: missing non-pressurized; Z supercharged; ZL supercharged medium cooling.

The last digit of the all-diesel engine model indicates the treatment method of the engine meeting the emission standard, among which no letter is a single pump, E is a high-pressure common rail, and F is an electronically controlled VE pump.The power in the clouds.

The model of the diesel engine is better to understand than the numbers on the back of the car. Directly, it is the number of cylinders + piston diameter (cylinder diameter). Piston diameter (cylinder diameter) x stroke x number of cylinders = displacement. The piston diameter (cylinder diameter) of the engine and the proportional value of the stroke are relatively fixed, and the long stroke is the high-attack engine and the supercharged engine.

The engine model is generally marked on the cover of the valve chamber. Of course, the specific model is different and the logo is naturally different. The first number is the number of cylinders, and the last few digits are the cylinder diameter. There are three meanings of letters, namely: 1. Cylinder arrangement without symbols is equal to series, V is equal to V-type cylinder row, P is equal to flat Horizontal type.

How to distinguish second-hand car engines

The identification method of used cars is as follows: Look at the appearance: Check whether the engine has oil leakage through the appearance, especially on hot days and high temperatures. Oil seals and rubber pads may age for a long time in high temperature environments, resulting in oil leakage. When you buy a used car, you have to check the details of the engine.

Look at the appearance: Check the engine through the appearance to see if there is oil leakage, especially in summer, when the temperature is high, the oil seal and rubber pad of the car may age in a long-term high-temperature environment, resulting in oil leakage. When buying a second-hand car, you need to check the details of the engine. If the cylinder pad leaks oil, it may cause a lot of trouble for future maintenance.

Check the internal condition of the engine through the oil filling port. Check the vehicle engine. First, open the oil filling port cover (oil cover) of the engine under the condition of cold car to observe the internal condition of the engine.Observe whether there is oil sludge accumulation in the internal cylinder block and whether there is carbon accumulation.

Look at whether the gaps around the hood of a used car are the same, and whether the gap between the wing plate and the hood and the windshield is the same. These subtleties are the standard for identifying the quality of an engine.

Identification of the hood: Pay attention to whether the gap around the hood is consistent, whether the gap between it and the windshield is consistent, whether the tightness of the wing plate is the same, and there should be no inconsistent size.

What is the difference between the engine?

1. It mainly lies in the difference in the ignition mode caused by the physical characteristics of the fuel, so as to show different thermal efficiency, economy, etc. In a gasoline engine, after the oil and gas mixture enters the cylinder, spark plugs are ignited when the compression is near the end.

2. The ignition method is different. The gasoline engine uses spark plug high-pressure discharge. After forming an electric spark, it ignites the combustible mixed gas in the gas cylinder; while the diesel engine relies on the mist-like diesel sprayed by the oil nozzle, and then ignites the fire in the cylinder.

3. Noise: due to gasoline engines and diesel enginesThe mechanical working principle is different. The pressure-combustion ignition method of diesel vehicles makes the diesel vehicle need to be compressed to a certain extent to emit power, so its burst sound will be relatively loud. In actual driving, it can be clearly felt that the diesel engine is louder than that of the gasoline car.