The difference between gasoline and diesel engines goes well beyond the obvious fact that the former uses gasoline as its fuel, while the latter uses diesel. Basically, both are internal combustion engines which convert the chemical energy derived from the fuel to mechanical energy required to power the car.
There do exist some more similarities between the two, like both resort to small explosions to ignite the fuel and have a four-stroke mechanism―the intake stroke, compression stroke, combustion stroke, and the exhaust stroke. The differences between them though, far exceed the similarities that exist.
Head-on Comparison of Diesel Engine and Gasoline Engine
Fuel and Spark Plug
One of the most obvious differences between these two types of engines is the fuel they use. As their names suggest, the diesel engine is powered by diesel, while the gasoline engine is powered by gasoline and other such volatile fuels.
A look at diesel-gas comparison and you will realize that the two fuels differ from each other to a great extent, which, in turn, reflects in the difference between the two types of engines as well.
How they Work: Ignition of Fuel
Both resort to small explosions to ignite the fuel. The difference between them, is the way these explosions are carried out. In gasoline engines, these explosions are carried out in a step by step process, wherein the fuel is mixed with air first, then the mixture is compressed by pistons, and eventually ignited by sparks produced by the spark plugs.
In contrast, the air is first compressed in diesel engines and fuel is added to the combustion chamber. As there are no spark plugs in diesel engines, they rely on the fact that air heats up when it is compressed, to facilitate the ignition of fuel.
The power generated by it using a single gallon of diesel far exceeds the power generated by a gasoline engine with the same amount of gasoline.
The fact that the former uses direct fuel-injection method, as opposed to the port fuel-injection method which is used in latter, gives it an edge in terms of fuel efficiency. Many auto experts are of the opinion that engine efficiency is the key reason why people opt for a diesel vehicle over a gasoline vehicle.
In terms of price, however, gasoline engines edge out diesel engines by a significant margin. The weight and compression ratio makes diesel vehicles slow in terms of acceleration. You also need to take into consideration the fact that diesel is cheaper than gas in most parts of the United States.
At one point of time, diesel vehicles were notorious for their tendency to pollute the environment. However, the ones in production today are more environment friendly as compared to those which were in production a decade ago.
At the end of the day, if speed is what you want, then you should go for a gasoline vehicle. However, if you want good fuel economy, then a diesel vehicle is your best bet.