We're still waiting until petroleum catches on. In the meantime we use our mule team to pull our trailer. Seriously, diesels have long been superior to gas engines in many ways: they extract more energy per gallon of fuel. That translates to better mileage and/or more power. For example, a Ford F350 with a 400hp V8 gas engine produces 400 pound feet of torque. The 400hp diesel for the same truck produces 800. That makes a big difference in power...double.
Large trucks have always been diesel due to the increased power. The EPA clean air regulations couldn't be met by diesels on smaller vehicles up until a year or two ago. Diesel exhaust contained lots of NOx, sulfur, soot, and smelled horrible. In addition, diesels were noisy. A few years ago, the Federal government mandated that all diesel fuel have very low sulfur content. This raised the price per gallon a lot, but it did stop those toxic emissions. More recently, car and truck makers have had to meet new standards for diesels.
As a result, modern diesels are pretty quiet - not much worse than gas engines, they don't emit soot, and have very few NOx emissions. In other words, they are tame enough to put on any vehicle. We replaced our 2013 F150 with a 2014 F350 diesel this winter. Had to due to our trailer being too much for the F150. From other F350 owners I hear that my mileage won't change much when towing. The F150 got about 18mpg without a load, and 10.5 mpg at the best when towing. The new diesel currently gets around 15mpg. That should improve as the engine gets to 10,000 miles. I understand that my mileage will be between 12 and 14mpg when we tow our trailer. I like that.
Diesels aren't a fad. In fact they were first. The first internal combustion engines were diesels. Before adding all the anti-pollution stuff, diesels are very simple engines. They have an extremely long life. A diesel can go for hundreds of thousands of miles without needing major service. Now instead of having the stinky old-fashioned diesel smell, our truck exhaust smells a bit like ammonia.
