Jackson_Slugger
$50 Site Donor 2022
Yes, I know ... using the term "credits" meaning using whatever means are used to achieve the monetary "pay-off" so to speak of meeting the fuel economy goals. There are lots of ways to do it, but seems oil viscosity is an easy way to do it ... easier than many other things.
These two chapters give an good overview of ways to get "CAFE credits".
4 Power Train Technologies for Reducing Load-Specific Fuel Consumption | Technologies and Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty Vehicles | The National Academies Press
Read chapter 4 Power Train Technologies for Reducing Load-Specific Fuel Consumption: Technologies and Approaches to Reducing the Fuel Consumption of Mediu...books.nap.edu
5 Vehicle Technologies for Reducing Load-Specific Fuel Consumption | Technologies and Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty Vehicles | The National Academies Press
Read chapter 5 Vehicle Technologies for Reducing Load-Specific Fuel Consumption: Technologies and Approaches to Reducing the Fuel Consumption of Medium- a...books.nap.edu
From Chapter 4:
Engine Friction Reduction
Reduced friction in bearings, valve trains, and the piston-to-liner interface will improve efficiency. Any friction reduction must be carefully developed to avoid issues with durability or performance capability. An example would be to develop heavy-duty diesel engines to run on 10W-30 oil instead of the current standard of 15W-40. The lower viscosity oil would reduce friction, at the expense of bearing capability. Fuel consumption improvement from one source[9] was 2 percent, whereas another source[10] claims 1 to 1.5 percent. The use of a thermatic oil cooler (thermostatically controlled oil cooler) in conjunction with lower viscosity lubricating oils could yield 1.5 percent improvement.[11] The effect of friction reduction and oil temperature control will be greatest during cold starts and under light load operation, where friction accounts for a larger portion of total energy consumption.
I'll read the links tomorrow. But Ford still recommends 5W-30 for the Ecoboosts (mostly anyways) IIRC. And yes fuel economy is a huge factor, but if it is the overweening one you portend, then why has Ford mostly deleted its fleet of economy, subcompact, and midsize sedans/H-backs in favor of SUV's? How many "CAFE" "pay-offs" are they getting for fielding a Ford Escape or Explorer over the deleted Fiesta?