Compare Diesel to gasoline

Diesel fuel has a higher energy density than gasoline. One gallon of diesel contains about 147,000 BTUs of energy, while a gallon of gasoline only has 125,000 BTUs. Which means it takes more gasoline to equal the power output of diesel, making diesel engines more efficient per gallon of fuel burned. Also, diesel engines use the more efficient direct fuel-injection method (fuel injected directly into cylinder) compared to the port fuel-injection setup in gas engines where gas is mixed with incoming air in the intake manifold, the diesel system has little wasted or unburned fuel.

today's diesel contains less sulfur than in past years, which means much less harmful soot. On top of that, new diesel cars are made with ingenious emissions-control systems such as BlueTec, which treats exhaust with a urea-based solution to reduce its toxicity.

Diesels and gasoline cars have their pros and cons. One thing makes it better for the economy and then another makes up for it.