CNG vehicle modification technology

CNG vehicle: It is the addition of compressed natural gas equipment on the basis of existing vehicles, achieving dual use of natural gas and gasoline
Fuel powered vehicles.
Advantages of CNG vehicles compared to gasoline fuel vehicles
(1) Choose clean energy to reduce usage costs. (2) Low exhaust pollution, can significantly reduce carbon monoxide and dioxins
Emissions of sulfur, carbon dioxide, etc. (3) Less carbon buildup and minimal wear and tear on vehicle components, reducing maintenance frequency and significantly lowering
Maintenance and upkeep costs. (4) Safe and reliable; The vehicle runs smoothly.
Composition of CNG system
Installation diagram of CNG vehicle 
The CNG system consists of the following three parts: (1) Gas filling and storage system: mainly composed of filling valves, wrapped steel cylinders, and high
Composed of crimping heads. (2) Gas supply system: mainly composed of pressure reducing valve, filter, gas common rail, etc. (3) Control electricity
Road system: mainly composed of conversion switches, ECU, solenoid valves, etc.
Compressed natural gas cylinders are equipped with caps, valves, and safety relief devices. The bottle cap can protect the bottle valve and ensure safe pressure relief on the valve
The device type is a combination of explosive disc and fusible plug. When the pressure or temperature limit of the steel cylinder is exceeded, the safety device will automatically release the pressure,
Protect the safety of vehicles and personnel.
Working principle: CNG enters the cylinder through the gas common rail after passing through the pressure reducing valve and filter. The pressure reducing valve is controlled by the ECU
Adjust according to different driving conditions of the vehicle. The optimal combustion state can only be achieved when the temperature of CNG is above 40 ℃, so it is necessary to
Before entering the engine, use the engine's antifreeze to heat the gas in the gas common rail. To achieve manual operation of oil and gas
The forced engine start for switching and using gas is equipped with a switch inside the cab. The conversion node of oil and gas is controlled by the ECU system
Automatically determine the switch based on the set parameters. Therefore, it has complete functions and is very easy to operate.

3 CNG modification and installation process Loong

Only manufacturers with CNG vehicle modification qualifications can carry out modifications. (1) Install fuel ECU; (2) Installation Gas path shut-off valve; (3) Install pressure regulator; (4) Install filters; (5) Install gas common rail; (6) Install conversion panel Switch. Debugging methods for CNG vehicles after installation (1) Gas filling: For natural gas leakage testing, slowly fill natural gas to approximately 10MPa and use leak detection liquid to check relevant departments After confirming that there is no air leakage, inflate to 20MPa and further carefully check for leaks. (2) ECU parameter setting (as shown in Figure 3). Figure 3 Oil to gas conversion: It must simultaneously meet the requirements of engine circulating water temperature above 40 ℃ and engine speed above 1400. The above two points Even if one of them is not met, the ECU will automatically switch from gas to oil. By adjusting the above parameters according to the different vehicle models The car is operating at its optimal state. (3) Road condition test: Adjust based on the performance of the vehicle under different conditions such as starting, acceleration, deceleration, curves, and slopes Adjust the parameters of the pressure reducing valve button and ECU until satisfactory. Emergency response measures: When there is an emergency situation such as gas leakage or traffic accident. The gas cylinder valve should be closed immediately, Vehicle power supply, etc., for self rescue. If the gas cylinder valve cannot be closed, efforts should be made to cool down the gas cylinder, evacuate personnel immediately, and isolate the fire Source, protect the scene, strictly prohibit smoking and fireworks, report to relevant departments as soon as possible for emergency response.