Natural Gas Generators vs. Diesel Generators: A Comprehensive Comparison of Usage and Manufacturing Processes

Natural gas（mainly methane） is gaseous, flammable, and explosive.

 It can easily explode when mixed with air and ignited.

Diesel is a liquid, less volatile, with a high flash point, 

making it less prone to gas explosions.

Spark-ignition: The piston compresses a mixture of natural gas and air

, which is ignited by a spark plug at the end of the compression stroke.

Compression-ignition: The piston compresses air, raising its

 temperature （above the diesel ignition point）, then diesel is 

injected and self-ignites to do work.

Pipeline natural gas usually has the lowest and most stable operational costs.

Costs increase when using liquefied natural gas（LNG）or compressed natural gas （CNG）.

Diesel prices fluctuate, and the cost per unit of energy is

 generally higher than natural gas. Diesel engines have relatively 

high thermal efficiency.

Lower power and torque, with a slight delay in load response. Best

 suited for stable base-load power or grid-connected operations.

High power, rapid response. High torque makes it suitable for 

handling sudden load increases, often used as backup power.

Clean and eco-friendly. It generates almost no particulate matter or sulfur 

compounds, and CO2 and NOx emissions are significantly lower than diesel engines.

Poorer emissions. It produces particulate matter（black smoke）,

 nitrogen oxides （NOx）, and sulfur oxides（SOx）.

Clean burning results in less carbon buildup and lower oil contamination,

 making maintenance easier. However, the ignition system（spark plugs,

high-voltage coils） requires regular replacement.

Durable structure with long lifespan. The fuel system（especially the 

precision injectors） is sensitive to fuel quality and requires high maintenance.

Flammable and explosive fuel, requiring stringent leak detection

, ventilation, and explosion-proof design.

Burns more smoothly with significantly lower noise levels compare

d to the same-power diesel generators.

Compression Ratio: Lower （typically 10:1 to 12:1）.

 A higher compression ratio could cause pre-ignition（knocking）. 

The engine structure can be lighter.

Compression Ratio: Very high（typically 16:1 to 22:1）. 

Needs to withstand extremely high explosion pressures, so the engine structure, including 

the cylinder block, pistons, connecting rods, and crankshaft, must be very robust and heavy.

Combustion Chamber Design: Relatively simple, designed to form 

a uniform mixture and promote flame propagation. Common designs

 include semi-spherical or dome-shaped chambers.

Combustion Chamber Design: More complex, designed to promote fuel-air mixing and 

compression-ignition.

Includes designs like omega-shaped piston tops matched with fuel injector spray patterns.

Core Components: Gas mixing system.

The key is precise control of gas flow and the formation of a homogeneous mixture. 

• Gas nozzles/throttle valve: Quick response and precise metering. 

• Mixer: Venturi tube principle to mix natural gas with air thoroughly.  

• Pressure Regulator（for LNG/CNG）: Reduces high-pressure gas to 

engine-required pressure.

Core Components: High-pressure common rail injection system. 

The “heart” of the diesel engine, requiring extremely high precision.  

• Fuel injectors: Micron-level nozzles requiring super-precision machining.  

• High-pressure fuel pump: Needs to generate pressures of 1600-2500 bar.  

• Common rail pipes: Thick-walled steel pipes to withstand ultra-high pressure.

Materials & Craftsmanship: Gas paths must be sealed effectively, 

utilizing stainless steel, copper alloys, and special rubber/PTFE seals to 

prevent gas leakage.

Materials & Craftsmanship: Fuel system components must use high-strength alloy steels

and undergo special heat treatments to cope with high pressures and the poor lubrication 

properties of diesel.

Must be equipped with a high-energy ignition system. 

 • Spark plugs: Special materials （like iridium） are required to withstand high

temperatures and chemical corrosion from gas combustion. 

Longevity is a manufacturing priority.  

• Ignition coils: Must provide stable, strong spark energy.

Often uses turbocharging with intercooling, but due to pre-mixed combustion,

 the turbocharger and mixer require higher precision to prevent “backfire.”

Typically equipped with a turbocharger, utilizing exhaust gas energy to compress intake air,

 improving efficiency and power. The turbocharger must withstand high temperatures and 

rotational speeds.

The after-treatment system is relatively simple, usually just: 

• TWC（Three-Way Catalyst）: Handles CO, HC, and NOx simultaneously, 

with high efficiency due to natural gas purity.

Complex manufacturing, often requiring a "combination approach":  

• DOC （Diesel Oxidation Catalyst）: Oxidizes CO and HC.  

• DPF（Diesel Particulate Filter）: Captures particulate matter and needs periodic regeneration.  

• SCR （Selective Catalytic Reduction）: Injects urea solution to reduce NOx emissions.

High power density, fast response, extremely high reliability, convenient fuel storage, 

and no reliance on fixed pipelines.

Base-load power generation（power plants, factory base-load）

, combined heat and power（CHP）, 

urban emission reduction projects, 

backup power where pipeline gas is available.

Suitable for backup power （hospitals, data centers）, 

mobile power （construction sites, ships）,

and off-grid power.

Control of gas: precise fuel delivery, reliable ignition system,

 comprehensive explosion-proof design.

For high voltage: high compression ratio, robust structure, 

and ultra-precise high-pressure fuel system.