Gas engines (spark ignition gas fuel engines) also follow the basic structural framework of the internal combustion engine's "two mechanisms+five systems". Their five systems are the same as gasoline engines, but due to the fact that the fuel is in gaseous form (natural gas, biogas, coal gas, etc.), there are significant differences in fuel supply and ignition:

Fuel supply system

Core task: Mix gas fuel with air at a precise air-fuel ratio (usually 15.5:1-18:1) and send it into the cylinder.

Key components: gas pressure regulator/pressure reducer, electromagnetic shut-off valve, mixer (or inlet injection device), gas source filtration and pressure stabilization component * *; No liquid fuel components such as fuel tanks and fuel injectors.

Characteristics: Dependent on ECU control of air-fuel ratio and ignition advance angle, requiring leakage prevention and anti freezing measures (especially for LNG/CNG low-temperature conditions).

Ignition system (essential for gas engines, different from diesel engines)

Function: Ignite premixed gas through high-voltage electric spark (natural gas has a self ignition point of about 650 ℃ and cannot be compressed).

Composition: battery, ignition coil, ignition module, spark plug (gap is usually 0.40mm), high-voltage wire, and ignition timing sensor.

Requirement: The ignition voltage should be higher (usually>40kV), and the spark plug should be cleaned/replaced regularly to prevent carbon buildup from causing premature ignition or misfire.

Cooling system

Function: Maintain stable working temperature and cope with the characteristics of high combustion heat load and high exhaust temperature of gas.

Attention: The quality of the coolant directly affects the efficiency of the gas heat exchanger, and inferior liquid is prone to scaling, leading to a decrease in power.

Lubrication system

Specialty: Gas specific low ash engine oil (sulfate ash content<1%) must be used to avoid premature combustion, detonation, or valve wear caused by the deposition of ash content in ordinary engine oil (gaseous fuel has no droplet lubrication effect).

Components: oil pump, filter, oil passage, etc., but the maintenance cycle is stricter.

Starting system

Composition: Battery, starter, starter switch, etc., convert electrical energy into mechanical torque to drive the crankshaft to rotate.

Difficulty: In winter, it is easy to have difficulty starting due to decreased battery performance, frozen gas containing water, or viscous engine oil.