Clean air is neither cheap nor simple.
Through the years, reducing exhaust emissions to meet federal and California limits for any kind of vehicle has cost billions of dollars and added complexity for owners. Will it be the same for operators of transport refrigeration units, which must meet Tier 4 Final emissions limits this January?

The answer will be yes for higher purchasing expense (how much higher, the reefer manufacturers aren't publicly saying), but the diesel engines on reefer units will avoid exhaust aftertreatment - and other design advancements will mean significantly better fuel economy.

Carrier Transicold and Thermo King representatives delivered this mostly good news during the recent annual meeting of the Truckload Carriers Association's Refrigerated Division in Idaho. They said they won't have to use diesel particulate filters or urea (diesel exhaust fluid) injection, two heavy and costly items used on trucks and road tractors since 2007 and 2010, respectively.

The two builders are accomplishing this in somewhat different ways.

Carrier has boosted component efficiency in its EcoForward units by 18% to 20% so they'll need less power to operate. The 2.2-liter Kubota diesel will make 21 to 22 peak horsepower and burn 5 to 20% less fuel, said Dave Kiefer, director of marketing and product management. They'll be well under the 25-horsepower threshold, where slightly more stringent emissions limits kick in for Tier 4-F.

The refined engine also won't need exhaust-gas recirculation, another thing now used on truck diesels. Output from these units will be more than enough for most applications, Kiefer said, so Carrier will not sell 25-plus-horsepower units in 2013. All its current models will be phased out.

Thermo King believes there will still be a need for high-capacity reefers and will offer them in its new Precedent S-600 models, said Tom Kampf, trailer product manager. Precedents have new advanced electronic controls, frame, cabinet, condenser and other components. Their re-engineered Yanmar diesels will use "light" exhaust-gas recirculation, but common-rail, high-pressure fuel injection, among other things, will otherwise help meet the limits.

They'll make power similar to the 34 horsepower produced under high load by current models. Because of larger and more capable components, an S-600 will weigh about 200 pounds more than a comparable current model, but it will get up to 27% better fuel economy.

Under-25-horsepower units will become more important, so Thermo King will also have those, called C-600, which will use a similar engine. The existing SB-230 model will continue through 2013 by virtue of EPA credits earned by the cleaner-burning S-600 units.

Electric-driven components play a big role in both companies' 2013 reefers. Like its current Vector units, Carrier's EcoForward engine directly drives a generator that powers the refrigerant compressor, condenser fan and charging system. In that sense it's diesel-electric, kind of like railroad locomotives. Thermo King's C-600 and S-600 engines directly drive the compressor, while a belt-driven generator powers the other items. Fewer belts (or none at all) mean fewer repairs and less maintenance, say both companies.

California has regulations tougher than the feds', and even newer reefers are limited to seven years of operation before upgrading or banishment from the Golden State. However, builders say the California Air Resources Board is approving the new products.

For its S600, Thermo King is seeking "evergreen" status, meaning it could stay in service indefinitely. So can certain TK and Carrier units equipped with a DPF, as well as those equipped with electric "stand-by" equipment that run electrically a minimum amount of time, as set by CARB's complex rules. (But they're a whole 'nother story.)