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.
Electric motors are not heat engines and cannot meaningfully be compared to combustion engines. However, large properly designed electric motors run at their best operating point can be in the 90's% efficient. Since the generator at a large electric power plant can be 98% efficient, I suspect that comparably sized electric motors can also reach this efficiency.