Greenhouse gas emissions clear skies

Gearing Up for New GHG Emissions Regulations

The Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) have adopted the first-ever GHG regulations for heavy duty engines and vehicles. These regulations are geared to improve fuel efficiency and cut carbon pollution. Implementation will begin in January 2017 for all US and Canadian manufacturers.

The program promotes a new generation of cleaner, more fuel efficient trucks. The final standards are expected to lower CO2 emissions by approximately 1.1 billion metric tons, save vehicle owners fuel costs of about $170 billion and reduce oil consumption by up to 2 billion barrels over the lifetime of the vehicles sold under the program.

Kenworth T680 Engine

Engine Updates

The regulations have spurred changes to many engine options, including:

MX-13 and MX-11  PX-7 and PX-9 ISX15
New engine ratings New EGR cooler Revised turbo
Fuel-efficient turbocharger & air compressor     Damper diameter increase Revised EGR cooler
Single canister aftertreatment  Single canister aftertreatment     Revised crank breather
Variable speed oil pump & coolant pump   Naturally aspirated air compressor
Fuel module with pre-filter   New fuel pump/lines
New harness routing   Composite oil pan
Valve cover material (MX-13 only)   Single canister aftertreatment

Aftertreatment Updates

PACCAR and Cummins engines will switch from a double to single-canister aftertreatment construction, offering larger diameter and longer length. Single-can construction is sized to meet engine horsepower ratings. Additionally, the DEF systems will include dosing system changes, EPDM hoses which are smaller and more flexible, as well as injectors that are DEF-cooled, eliminating the need for coolant.


The new GHG regulations offer fleets increased fuel efficiency, with gains being tested in the 2-4 percent target range. Additionally, component updates create easier serviceability and significant weight reduction, particularly to the engine and aftertreatment systems. Talk to your MHC representative today to have your fleet evaluated for compliance and learn about the latest product updates.

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