Diesel Vs. Gasoline Generators: Which is better?

Diesel Vs. Gasoline Generators
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    People worldwide rely on electricity to power their everyday electrical equipment. Electricity is critical to homes, hospitals, businesses, etc. Electricity is distributed through the grid and flows from the generating plants or units to the end user. Continuous power is required to ensure no interruption of service. This is especially important in hospitals, shopping malls, security centers, airports, etc. Even brief power outages in these facilities can be dangerous.

    The generator is used as a backup power source during a power outage. They can help ensure a continuous power supply to critical facilities. Most generators run on diesel or gasoline.

    Difference Between Diesel and Gasoline Generators

    In this post, we’ve shared the differences between diesel generators and gasoline generators to make it easy for customers to choose the right one for their needs. 

    Placed on the ground to show two BISON generators

    Working principle of a diesel generator

    The high-pressure atomized diesel fuel sprayed by the fuel injector is thoroughly mixed with the clean air that has been cleaned by the air filter before entering the cylinder of the diesel engine. Under the upward compression of the piston, the volume decreases, and the temperature rises rapidly, reaching the ignition point of diesel. Work occurs when the diesel fuel is ignited, the mixed gas burns strongly, the volume quickly expands, and the piston is pushed downward. Each cylinder performs work in a particular order, and the thrust on the piston acts as the force that pushes the crankshaft through the connecting rod, making the crankshaft rotate.

    Working principle of a gasoline generator

    In the cylinder of a gasoline engine, the mixed gas burns violently, and the volume expands rapidly, pushing the piston to work downward. Each cylinder performs work in a particular order, and the thrust acting on the piston becomes the force that pushes the crankshaft to rotate through the connecting rod, thereby driving the crankshaft to rotate. By installing the brushless synchronous alternator coaxially with the gasoline engine’s crankshaft, the spinning of the gasoline engine can power the generator’s rotor. The generator will give the induced electromotive force as output and produce a current through the closed load circuit using the electromagnetic induction principle. 

    different working principles

    It can be concluded from the above that in a diesel engine, the mixture is compressed into heat energy, and the mixture of fuel and air in the cylinder of a gasoline engine is marked by a spark plug; the volatility of diesel is lower than that of gasoline, and the number of gallons per gallon is more significant. Calorific value, that is, 5dm3 diesel can get more power than 5dm3 gasoline; 

    In a diesel engine, when the fuel is injected into the cylinder, the fuel and air are mixed. Whereas in the gasoline engine, fuel and air are in the carburetor, and intake air mixes in the pipe. Since mixing must occur immediately after fuel injection, diesel generator sets require specially designed combustion chambers to smoothly carry out the mixing of diesel and air. This is why the planning and production of combustion chambers are essential for diesel generator sets.

    The difference in working principle 

    The most fundamental difference between the two generators is how each type of generator burns fuel to generate power

    Diesel generators rely on compression to raise the temperature of the fuel, causing ignition and combustion. 

    Gasoline generators require an ignition source – a spark plug – which helps create combustion when there is fuel in the combustion chamber. Compression methods are generally considered safer than spark-induced methods.

    Diesel vs. gasoline generator: Side-by-side comparison 

    Let’s have a side-by-side comparison of each feature of diesel and gasoline generators. 

    1) Gasoline vs. diesel fuel

    Let’s first discuss gasoline and diesel as fuels for generators. 

    Gasoline is more flammable than diesel. If you’re storing fuel in an area with high heat sources or open flames, as in a garage, diesel is a much safer choice because it has no risk of accidental ignition.

    Diesel also has a longer shelf life than gasoline. In good conditions, diesel fuel can last 6 to 12 months without additives. Gasoline, on the other hand, only has a shelf life of about three months without additives. The shorter shelf life means gasoline must be handled and used at two to four times as much as diesel. This usage requirement can add substantial costs to owning a generator.

    Another benefit of diesel fuel is that it may be more readily available than gasoline in an emergency. Since most vehicles and small generators run on gasoline, fuel competition will increase during a power outage. However, diesel fuels fewer generators and cars. This means you’ll have to spend less time waiting at the pump to refill the tank.

    2) Efficiency

    One advantage of diesel generators over gasoline generators is their fuel efficiency. Diesel generators use less fuel than gasoline generators. 

    Here’s why: In a diesel generator, compression ignites the fuel. Fuel and air enter the engine separately. Only air is compressed, which allows the engine to run more efficiently by using less fuel.

    In contrast, gasoline generators reduce fuel efficiency by mixing fuel and air in the carburetor before compression.

    Since diesel generators are more fuel efficient, they run longer on the same amount of fuel. As a result, they will have lower operating costs and provide uninterrupted power to your home or facility.

    3) Noise and heat

    Time has passed, and older models of diesel generators are noisy and not suitable for use in high-density neighborhoods. However, since there are no carburetors or spark plugs, modern models run quieter and require less maintenance than gasoline generators. An 1800 rpm water-cooled diesel generator will run 12,000 to 30,000 hours before needing an overhaul. By comparison, similar gasoline generators require service after 6,000 to 10,000 hours of operation.

    Gasoline generators are great for small jobs. Because they run quieter than diesel-powered generators, you can use them in tight or dense spaces without distraction, such as at your local market.

    4) Air-cooled or liquid-cooled

    Generators are either air-cooled or liquid-cooled. Whether the generator is diesel or gasoline-powered, liquid cooling units are generally more expensive and used for larger projects.

    Homeowners who want a generator for occasional short-term power outages may consider an affordable air-cooled gasoline generator. For extended or long-term use, such as job sites and remote sites, liquid-cooled diesel generators—though more expensive—may be the best option.

    5) Running in cold temperatures

    When it comes to running well in cooler temperatures, gasoline-powered generators have clear advantages. Because diesel generators use compression rather than ignition sparks, cold weather conditions can make it difficult for them to generate the heat needed for combustion. This problem can sometimes be solved by using a glow plug, the equivalent of a wire that conducts electricity.

    6) Durability

    Diesel generators need less maintenance than gasoline generators. The longer the gasoline generator runs, the higher the temperature. Diesel generators don’t have this problem. That’s why diesel generators are more durable. 

    7) Life

    Diesel generators are more suitable for long-term use than gasoline generators. Mostly, larger diesel generators are liquid-cooled, while smaller generators are air-cooled. For prolonged use, liquid-cooled models have an advantage, as air-cooled models can overheat during prolonged use, especially at higher ambient temperatures.

    Diesel generators are also designed to work for long periods under heavy loads. They perform better under heavier loads than under light loads, so when you need them, they perform best when running. Only intermittent use is permitted for gasoline generators.

    Major power outages are not what they are intended for. 

    Diesel generators will last longer than gasoline generators. This is because gasoline burns hotter than diesel, resulting in a shorter lifespan for gasoline generators. 

    Advantages of diesel generators

    • Diesel generators are more efficient and reliable due to their simplified design
    • It uses less fuel than gasoline generators
    • long term application
    • Diesel generators are safer because they are less volatile
    • it requires less maintenance

    Disadvantages of diesel generators

    • It is more expensive than a petrol generator
    • Diesel generators have a huge generator set

    Advantages of gasoline generators

    • easy to get
    • It is more portable due to its size and weight
    • Gasoline is much cheaper than diesel
    • Noise is easier to manage

    Disadvantages of gasoline generators

    • For short-term use only
    • consume more fuel

    Final thoughts: Which generator is better?

    Despite the fact that the majority of us are used to thinking of diesel as being expensivecompared to gasoline, this is frequently not the case with generators. Diesel fuel is more expensive than gasoline, but diesel generators are also much more fuel efficient than gasoline generators, which typically consume about 50% more fuel. As a result, diesel generators are often cheaper than gasoline generators over time.

    A gasoline generator may be a safer option for occasional or temporary use. This works for several reasons. Compared to diesel generators, they are generally cheaper and come in more models and price ranges, which is one of the few advantages of their reduced capacity. Gasoline generators are also quieter and produce less toxic carbon dioxide gas.

    Even diesel fuel is self-lubricating, which means the fuel delivery system lasts longer than a gasoline engine, ideal if the generator has not been used for a while. Diesel generators might be more expensive to repair when they break down while having a longer lifespan and a lower failure rate. 

    While diesel generators get praised for their fuel efficiency, gasoline generators are now designed with various economy modes and features to overcome the gap. But the disadvantage of gasoline generators is that they are hotter than diesel generators. Over time, this causes more wear on generator components, which means more frequent maintenance and repairs.


    In the end, most industrial companies will probably justify diesel generators as the best option for gasoline generators. Still, the best answer depends on your needs and what you’ll be using the generator for. Those with higher power requirements may opt for a heavy-duty diesel generator, while those with fewer power requirements may benefit from an affordable gasoline generator.

    Whether you choose a diesel generator or a gasoline generator, BISON can help!

    As China’s gasoline and diesel generator experts, we can advise on which type is best for you. Call our team of experts at (+86) 13088619098 today!

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