With the continuous promotion of
Clean energy in commercial vehicles, CNG compressed natural
Gas Engines are widely used in heavy-duty trucks, buses, and construction vehicles due to their advantages of low
Fuel cost, clean emissions, and stable operation. CNG
engines belong to high-pressure gas power equipment, and the installation process is highly specialized. Standardized operation is the core to ensure the safety of the entire machine and extend its service life. This article explains the installation and correct use of FARIZON
CNG Engine from several aspects, including preliminary preparation, installation points, debugging and acceptance, daily operation, and maintenance taboos.
1、 Preparation before installation, control hardware and environmental foundation
The installation of CNG engines should not be blindly constructed. The early preparation directly determines the safety of the later operation of the whole machine. It is necessary to do a good job in three aspects: model verification, accessory verification, and site protection.
Firstly, verify the engine body model, confirm the cylinder pressure and electronic control system version that the engine is compatible with, and confirm that the complete set of original accessories such as wiring harness, pressure reducing valve, high-pressure pipeline, gas injection valve, ECU controller, etc. are complete. It is prohibited to mix non-standard auxiliary components. CNG belongs to high-pressure fuel, and high-pressure pipelines, joints, and sealing gaskets must use original factory specified accessories to avoid potential gas leaks in the future.
Secondly, conduct an environmental assessment for installation. The engine area should be kept away from high-temperature heat sources and a safe distance should be maintained from the exhaust system to prevent the gas pipeline from being baked by high temperatures. The installation site should be kept ventilated, away from open flames and electric sparks, and equipped with gas leak detection equipment and dry powder fire extinguishers. At the same time, check the strength of the frame installation base, ensure that the flatness and load-bearing capacity of the base match the weight of the engine, and avoid bracket cracking caused by operational vibration.
Finally, complete the pre inspection of the components, check that the high-pressure gas cylinder, gas cylinder valve, and safety valve are not damaged or bumped, and that all pipelines are kept clean and free of iron filings and impurities to prevent foreign objects from entering the gas system and causing valve body jamming faults.
2、 Core technology for installation of complete machine and gas system
The installation of CNG engines is divided into three modules: mechanical body assembly, gas supply system layout, and electrical circuit docking, and each step must comply with technical specifications.
The engine body is fixed to the frame base according to the original factory torque standard, the shock absorber pads are fully assembled, and the bolts are tightened in diagonal order to reduce the risk of loosening caused by driving vibration. The gas system is of utmost importance in installation. Rubber buffer pads are installed on the fixed brackets of high-pressure gas cylinders, and the gas cylinders cannot directly contact the metal brackets to prevent wear and tear on the cylinder body during driving; Reserve seismic bends for the layout of high-pressure pipelines, with a fixed spacing of no more than 600 millimeters between pipe clamps. Install protective rubber sleeves at the locations where metal partitions pass through to avoid friction and cutting of the pipelines.
The pressure reducing valve is installed in a location with low vibration, with the diaphragm arranged vertically on the ground, away from high-temperature components such as exhaust pipes. The cooling water circulation pipeline is reliably connected to ensure the cooling effect of the pressure reducing valve. The solenoid valve should be installed strictly in the direction of airflow, with the coil facing vertically upwards and not inverted. The electrical wiring harness should be kept away from the exhaust pipe and sharp metal edges. The wiring harness joints should be well waterproofed, and the ECU controller should be well shock protected to avoid water ingress and vibration that may cause signal abnormalities.
After the installation of all pipeline joints is completed, direct inflation is prohibited. All threaded joints should be sealed to ensure that the pipeline direction is regular and does not interfere with the moving parts of the chassis.
3、 Debugging and airtightness acceptance, testing must be conducted upon completion of installation
After the assembly of the whole machine is completed, it cannot be directly put into use. Air tightness leak detection and whole machine debugging are the last checkpoint of safety, and this step cannot be omitted.
The first step is to conduct air tightness testing, turn off the engine, introduce compressed natural gas at the specified pressure, use a gas detector or soapy water, and perform leak detection on all interfaces of the gas cylinder valve, high-pressure joint, pressure reducing valve, and injection valve one by one to confirm that there are no bubbles or alarm leaks. Once a leak is detected, immediately release the pressure, inspect the seals and joints, and conduct a re inspection after repair. Only after passing the leak detection can the power on debugging be carried out.
Subsequently, perform power on debugging, connect the vehicle power supply, start the engine, idle first, observe the gas pressure and water temperature parameters, and check that the ECU system has no fault codes. Observe whether the idle speed is stable, whether there is any shaking or abnormal noise; Gradually increase the engine speed, test the power output under different operating conditions, and confirm that the gas switching and fuel injection logic are normal. The debugging process focuses on the working status of the pressure reducing valve, observing that the pressure value is stable and there are no abnormal pressure fluctuations.
All tests must be qualified, installation records must be organized, and leak detection and debugging reports must be retained before delivery for use.
4、 CNG engine daily standard use and operation
Correct operating habits can reduce the occurrence rate of failures and leverage the performance advantages of CNG engines. When starting the vehicle, wait for the engine water temperature to rise to 80-90 ℃ before entering gas mode. Directly using gas at low temperatures can easily cause the pressure reducing valve to freeze, increase gas consumption, and damage sealing components.
Gas filling must be done with the engine turned off and the gas cylinder shut-off valve fully opened; If the vehicle is parked for a long time, be sure to close the manual shut-off valve of the gas cylinder. During the driving process, always pay attention to the gas pressure alarm on the dashboard. If the pressure is lower than the warning value, add gas in a timely manner. Do not continue to work under low pressure, as insufficient gas supply can easily damage the three-way catalytic components. Try to add compressed natural gas that meets the standards for vehicles. Poor quality gas with high impurities and high hydrogen sulfide will corrode valves and injection valves, and shorten engine life.
If you smell a gas odor while driving, immediately turn off the engine, close the main valve of the gas cylinder, evacuate personnel, prohibit ignition and smoking, and wait for troubleshooting and repair before continuing to use.
5、 Regular maintenance and usage taboos
CNG engines require specialized maintenance of the gas system in addition to regular oil and filter maintenance. Regularly tighten the gas cylinder bracket and pipeline clamp; Regularly verify safety valves and pressure gauges; Replace the gas filter element according to the maintenance cycle, filter out moisture and oil in the gas, and protect the injection valve. Priority should be given to using gas specific models for spark plugs, which should be replaced periodically to avoid poor ignition causing a decrease in power and an increase in gas consumption.
There are clear taboos for daily use: it is prohibited to dismantle gas cylinders and cylinder valves without authorization; Prohibit maintenance of gas components in open flame environments; Before disassembling the pipeline, the high-pressure gas inside the pipeline must be completely released, and it is strictly prohibited to disassemble the joint under pressure. It is not allowed to modify ECU parameters or alter pipeline layout arbitrarily, as modification will directly damage the safety performance of the entire machine. Discover faults and promptly go to FARIZON authorized service stations for maintenance. Non professionals are prohibited from disassembling gas components.
Conclusion
The safe operation of CNG engines begins with standardized installation and ends with standardized use. Strictly following the installation process, conducting air tightness testing, and adhering to daily maintenance can not only fully leverage the low-cost and low emission advantages of CNG power, but also avoid gas system safety risks, ensuring stable and reliable operation of vehicles in long-distance transportation, urban passenger transportation, and engineering operation scenarios.
