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.
Diesel engines generally achieve greater fuel efficiency than petrol (gasoline) engines. Passenger car diesel engines have energy efficiency of up to 41% but more typically 30%, and petrol engines of up to 37.3%, but more typically 20%. That is one of the reasons why diesels have better fuel efficiency than equivalent petrol cars. A common margin is 25% more miles per gallon for an efficient turbodiesel. For example, the current model Skoda Octavia, using Volkswagen engines, has a combined European fuel efficiency of 41.3 mpg for the 105 bhp (78 kW) petrol engine and 52.3 mpg for the 105 bhp (78 kW) â and heavier â diesel engine.