Below are some notable blended HFC mixtures. There exist many more (see list of refrigerants). All R-400 (R-4xx) and R-500 (R-5xx) hydroflurocarbons are blends, as noted above. 1  R-401A is a HCFC zeotropic blend of R-22, R-152a, and R-124. 2  It is designed as a replacement for R-12. R-401A is a HCFC zeotropic blend of R-22, R-152a, and R-124. 2  It is designed as a replacement for R-12. 3  R-404A is a HFC nearly azeotropic  blend of 52 wt.% R-143a, 44 wt.% R-125, and 4 wt.% R-134a. 4  It is designed as a replacement of R-22 and R-502 CFC.
Diesel vehicles may be making a comeback. Diesel engines are more fuel-efficient and have more low-end torque than similar-sized gasoline engines, and diesel fuel contains roughly 10% to 15% more energy than gasoline. So, diesel vehicles can often go about 20% to 35% farther on a gallon of fuel than their gasoline counterparts. Plus, today's diesel vehicles are much improved over diesels of the past.
Find Ratings. It has been touted as the automotive holy grail, the ultimate marriage of better performance and greater fuel economy. Itâs the direct-injection (DI) engine, the latest technology designed to squeeze more mpg out of cars. And it has actually been delivering results. For example, the Mazda3âs combined fuel economy jumped from 28 mpg in 2010 to 32 mpg in 2012 in our testing of the new Skyactiv engine.