Why do diesel engines obtain good gas mileage?
Diesel engines don’t have to be spun over 2,000 rpm to make all their horsepower. They have tremendous torque. The lower rpm saves fuel. Average RPM over the road is 1,200 RPM. The motors last forever. The entire fuel injection system is bathed in very light fuel oil / kerosene mix. So are the combustion chambers, rings and pistons constantly being lubricated up top of the pistons. Compression ratios up to 22:1 because high quality fuel oil / kerosene mix has a very high cetane rating, The higher the cetane rating the slower the fuel burns and the better efficiency of the engine.
