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CNG related knowledge

browse: source: time:2019-07-02 classification:Common problem

CNG car


A CNG (Compressed Natural Gas) car is a car that uses compressed natural gas instead of conventional gasoline or diesel as a fuel for automobiles. At present, the areas with natural gas pipelines at home and abroad are mainly based on the development of CNG vehicles.


CNG automobile means that natural gas mainly composed of methane is stored in a cylinder similar to a fuel tank in a car at a pressure of about 25 MPa, and is used as an automobile fuel. The main process is to reduce the 0.3~0.8MPa low-pressure natural gas at the CNG bus station, and then boost it to 25MPa through the natural gas compressor. It is controlled by the sequential control panel and stored in the high, medium and low pressure sequence to the gas storage cylinder group, and then the CNG dispenser. Fill the car cylinder. The autoclave of the automobile cylinder is decompressed by the decompression device and then supplied to the engine through the gas mixer.


A vehicle that uses compressed natural gas (CNG) as a fuel for automobiles is called a CNG vehicle. For the in-use vehicle, the modified gasoline vehicle is modified, and a dedicated compressed natural gas device is added while retaining the original vehicle fuel supply system. Forming a "CNG dual-fuel car", the conversion of fuel requires only a toggle switch. Adding one charge of natural gas can drive about 200 kilometers, especially suitable for buses, city taxis, buss with a round-trip mileage of no more than 200 kilometers, cars in the plane and other vehicles in the unit.


1. The fuel price is cheap;

2. The vehicle exhaust pollution is small;

3, no carbon deposits and small loss of vehicle components;

4. Safe and reliable;

5, the vehicle modification is simple;

6. The vehicle runs smoothly.


Natural gas burning point is more than 650 degrees, it is not easy to ignite; density is low 0.48, it is difficult to form combustion concentration in fire; octane number is up to 130 anti-explosion performance, explosion limit is only 5-15%, so it is safer than gasoline . Vehicle gas cylinders are used after passing fire, explosion, falling, shooting and other tests. In the past 60 years since the development of natural gas vehicles in China and abroad, there have never been instances of vehicle accidents caused by natural gas explosions and burning.


Advantages of burning CNG compared to burning gasoline:

1. Save fuel costs and reduce transportation costs.

1 cubic meter of natural gas is equivalent to 1.1-1.3 liters of gasoline.

2. It is safer than fuel.

The self-ignition temperature of CNG is 732 °C, and the auto-ignition temperature of gasoline is 232~482 °C. At the same time, the specific gravity of natural gas is only 0.6~0.7. Once leaked, it can spread rapidly in the air, and it is not easy to gather outdoors to reach the explosion limit.

At the same time, CNG is non-carcinogenic, non-toxic and non-corrosive. No major burning or explosion accidents have occurred. From the experience of using CNG for more than ten years in China, natural gas vehicles are safer than fuel vehicles.

3. CNG fuel has good anti-riot performance.

The turbidity of CNG is equivalent to the octane number of gasoline is around 130, and the highest octane number of gasoline currently used is only about 96, so CNG does not require additives as an automobile fuel. Such as anti-explosive agents such as lead.

4. CNG cars have good environmental protection effects.

Using CNG instead of gasoline as a fuel for automobiles can reduce CO emissions by 97%, CH compounds by 72%, NO compounds by 39%, CO2 by 24%, SO2 by 90%, and noise by 40%. Moreover, CNG does not contain toxic substances such as lead and benzene. Therefore, CNG is the fuel of choice for the automotive transportation industry to solve environmental problems.

5, burning CNG can extend the maintenance cycle of the car engine.

The car engine is powered by CNG, and the engine runs smoothly and the noise is low. No heavy hydrocarbons can reduce carbon deposits, extend vehicle overhaul time by more than 20%, and extend the oil replacement cycle to 15,000 km.


Gas-saving coup


First, lightly step on the throttle when starting, and accelerate the start in sequence.

The pursuit of speed and energy savings is contradictory. According to the driver's experience and statistics, when the throttle is reached at a speed of 60 kilometers per hour and gradually accelerates to 60 kilometers, the two methods differ in time by about 10 seconds, but the throttle ratio is heavy. Starting at normal speed, it will increase by 2 to 3 times in terms of gas consumption.

Second, reduce the brake frequency and maintain the distance.

When the driver does not pay attention to maintaining the distance during driving, the driver will frequently brake with the driving conditions of the preceding vehicle. First of all, when braking, the self-discharging gear is lowered. When the gear is adjusted again, the car needs to be pulled from the low-speed gear to the high-speed gear. One reduction, one lift, static start and low speed start, the engine consumes more. High volume.

Secondly, between the two points, the distance of the straight line is the shortest. If the lane is changed frequently without notice, the driving distance will be lengthened. Compared with the straight-line driving vehicle, any lane change will consume more air. We assume that we often change lanes to overtake. In order to drive away the distance from the adjacent vehicles, we will step on the throttle. Therefore, the driving style of changing lanes increases the air consumption.

Third, keep the speed, limit the height limit.

At present, most highways in China have a speed limit of 120 km/h. In the high-speed driving state, in addition to increasing safety hazards, the higher the speed, the greater the impact of gas consumption. The resistance and speed of a car are in a geometric square product, not a proportional relationship. The higher the speed, the greater the wind resistance and the greater the driving resistance.

For example, if you are running long distances, if you are within 100 and 120 kilometers, you will be more fuel-efficient. If you run really fast, you will be more fuel-efficient. It feels that you need power, the engine is always supplying oil, and high-speed driving is also detrimental to fuel consumption. If the speed of the vehicle is taken as the abscissa and the fuel consumption is taken as the ordinate, it is a curve of a fish hook. Too low speed is also relatively expensive, too high speed will increase the amount of gas used.

Four, four flat and stable, standard driving.

Vehicle deviation is also one of the main reasons for the gas. Because the four-wheel imbalance will cause the engine to provide more power and consume more air, it is necessary to regulate the driver's driving rules and develop good driving habits. The usual measures of consumption.

Fifth, strengthen self-inspection and timely maintenance.

There are many reasons for the high gas consumption. In addition to the above problems, there may be some problems with the equipment. The driver needs to strengthen the daily self-test frequency of the equipment. Sometimes the gas consumption is too high because a joint is loose or sealed. Due to strict air leakage, daily security and self-inspection must be strengthened. Driving after inspection can not only effectively improve the safety of travel, but also find problems in time to reduce gas consumption and recover losses. At this point: When you find any problems with the equipment, you should contact the professional and qualified enterprise to help inspect and repair, avoid major safety accidents caused by air leakage, and cause unnecessary trouble.

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