Carrier Transicold’s 2008 trailer product line-up is said to offer better fuel efficiency and lower sound output than previous models. The units also feature engines that “significantly” surpass U.S. Environmental Protection Agency (EPA) Tier 4i standards and California Air Resources Board (CARB) emissions requirements too.

With a threshold of 0.3 grams per kilowatt-hour (g/kwh), the Tier 4i standard lowers emissions by 50% for trailer refrigeration units with 25-50-hp engines compared with the preceding EPA engine standard. But Carrier says particulate emissions have been reduced 30% beyond that standard. As well, Carrier says its Tier 4i engines emit 19% fewer combined nitrogen oxides and hydrocarbons than the EPA threshold.

As a result of various improvements, the engines are said to be 1 to 2% more fuel efficient and about 1 dB quieter than Carrier’s previous engines.

You’ll find the Tier4i engines models 2100, 2100A and 2500A from Carrier’s X2 Series, as well as the Ultima, Ultra, and Genesis models.