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What Are The Differences Between Gasoline And Diesel Engines?

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Both the diesel and gasoline engines are internal combustion engines. However, the way the engines begin the cycle is a bit different. That is not where the differences end.

How the Engines Work

The main difference between gasoline and diesel is the way the engines fire. Fuel mixes with air, compressed by pistons and ignites from the spark plugs in a gasoline engine. A diesel is a bit different because the air is compressed first before the fuel is injected. This is because a diesel engine does not have any spark plugs. A diesel engine has a high compression ratio between 14:1 and 23:1. However, gasoline engines have a ratio ranging between 7:1 to 10:1.

The high compression ratio of a diesel engine provides more efficiency compared to gasoline engines. Diesel fuel is more syrup-based which means in energy terms it is heavier than gasoline. Therefore, less diesel is required to do the same job as gasoline (because of the weight factor). Biodiesel can be used as an alternative to foreign petroleum. It is a mix of soybean oil, animal fats, and recycled cooking oil, making it cheaper than regular diesel fuel.

Horsepower and Torque

Both engines have horsepower and torque. The difference is that when you accelerate the engine, the diesel engine has the capability to move large loads because of high torque. However, the diesel will not rev-up high, which creates less horsepower than is provided with a gas engine. For example, this is why sports cars do not have diesel engines because they do not have a quick response time. The diesel can handle the real-power for pulling loads such as trailers.


Diesel images have changed over the years leaving the smoky and smelly image of diesel in the past. This smell was caused partly because of sulfur burning, (present in diesel fuel). Modern technology has allowed the engines to be more difficult to spot. The newer vehicles are running much cleaner, but diesel still does not burn as clean as gasoline.

Additives are used to clean the diesel vehicles, as well as more filters to clean the emissions. Direct Fuel Injection or DFI is a new advancement in technology. It is also more precise than fuel injection and has produced cleaner emissions for both gas and diesel engines.

As you now see, there are many similarities between the two engines, but there are also many differences. As time progresses, both engines should be equally effective. This will take time and more research, but it will happen. Click here for more info.