By Jim Taylor, Editor MACS ACTION Magazine
The chattering classes have recently been in an uproar about the new fuel efficiency targets for light motor vehicles. The scare-mongers are already predicting a future full of Smart cars and other miniatures. Won’t happen; here’s why.
The public is conditioned to understand miles per gallon. However, the new regulations are actually mandating reduced emissions from all sources, and not just the engine. Savvy manufacturers may choose to reap credits from various sources depending on what is economically sound for their case.
In typical government fashion, some of the options are arcane, some are sensible and some are head-scratchers. First, some basic science: burning one gallon of gasoline results in 8,887 grams of CO2. If the vehicle can go 20 miles on that gallon, then it’s 8,887 divided by 20 to give 444.3 grams per mile of CO2. At 30 mpg, it’s 296.3 gm/mi, and so on.
All the other emissions from the vehicle – methane, nitrous oxide, refrigerant, fuel vapors, etc –have CO2 equivalent values and those can be computed and figured into the overall total. Reduce any of them and the total atmospheric effect is reduced. By 2025 the goal is to have a new car fleet averaging 163 g/mile CO2-equivalent; do that math backwards and you’ll end up at the 54.5 mpg number.
The new federal targets allow manufacturers to claim credits for a number of reductions. Remember also that the whole discussion of CAFÉ is averaged across an entire year’s production of all vehicles. A change here can offset an unchanged vehicle over there.
For instance, in 2017 manufacturing a vehicle with no CO2 emissions (think all-electric) counts as two clean vehicles in your fleet. The multiplier drops off in subsequent years, but the plan encourages non-combustion vehicles.
U.S. buyers love their pick-up trucks but their need to carry load weight often means smaller engines won’t work. But various hybrid powerplants will, and in 2017, using a “mild” hybrid system brings a 10 g/mi credit, and a “strong” hybrid system garners twice that number.
OEMs can pick up nearly 19 g/mi in car credits for using tighter A/C systems and low-GWP refrigerants; using the same tech on a pickup brings a credit of 24.4 g/mi.
Manufacturers can also get up to 10 g/mi of credits from a “buffet line” of possible additions. All that’s required is to show that you’ve either reduced emissions or improved mpg via any related technology: stop-start systems, active aero (grill shutters, etc), energy recovery, solar, and so on.
So using just the numbers mentioned here, let’s consider that 20-mpg pickup truck that puts out 444 g/mile of CO2. Give it a mild hybrid assist system, a new-design A/C system with HFO-1234yf, and include a few tricks from the aero and electrical buffet. Apply your relative credits (10+24.4+10 g/mi), and presto—the g/mile rating is reduced to 400. That equates to 22.21 mpg. All of the improvements will increase efficiency, and the manufacturer picked up a theoretical 2.2 mpg rating with no substantial (expensive) changes to the powertrain.
When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.
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The 32nd annual Mobile Air Conditioning Society (MACS) Worldwide Convention and Trade Show will take place January 18-20, 2012 at the Rio All Suite Hotel and Casino in Las Vegas, NV.