Announcements about new natural gas engines, bi-fuel engines and aftermarket conversion systems are coming faster and faster.
A recent sampling:

EcoDual Achieves EPA Approval for the Cummins ISM 11L Engine
EcoDual LLC, a provider of dual fuel conversion systems for heavy-duty diesel trucks, has achieved authorization from the U.S. Environmental Protection Agency to begin installing its systems on all 29 engine families of the 2004 to 2009 Cummins ISM engines.

Chrysler Begins Production of Ram 2500 CNG Pickup Truck
Chrysler announced that the first Ram 2500 Compressed Natural Gas pickup trucks began coming off the assembly line at the company's Satillo, Mexico, assembly plant, on Oct. 29.

Peake 'Diesel Natural Gas' Offers Dual-Fuel Conversion for New Cummins ISX Engines
Peake Fuel Solutions has a new product called "Diesel Natural Gas," or DNG, that allows truck owners to run a Cummins ISX 15 engine on a combination of natural gas (CNG or LNG) and diesel, or on 100% diesel.

Cummins Westport Plans Natural Gas ISB6.7 for 2015
Cummins Westport Inc. says it has begun development of an ISB6.7-G, a midrange 6.7-liter natural gas engine designed for medium-duty trucks and C-class school buses. It will enter production in 2015.

Test Drive: The Cummins Westport ISX12 G
Equipment Editor Jim Park evaluates the Cummins Westport ISX12 G in a Kenworth/Cummins Westport Inc. field test unit based at the Paccar Technical Center in Mt. Vernon, Wash.

Eaton UltraShift Plus Certified for Use with Westport 15-liter Natural Gas Engine
Eaton's UltraShift Plus automated heavy-duty transmissions have been certified for use with the Westport HD 15-liter high pressure direct injection liquefied natural gas engine (made by Westport Innovations Inc.).

Kenworth Offers New Dual LNG Tank Configurations
Kenworth is expanding its line of green products by offering factory-installed, dual liquefied natural gas fuel tanks on Kenworth T800s powered by the 15-liter Westport GX engine.

Dual-fuel conversion saves big money every day, supplier-trucker says
A band wagon powered by natural gas seems to have begun rolling, but most of those aboard talk about brand-new heavy trucks with special gas-burning engines. Why not convert existing trucks and engines to use cheap and clean-burning gas?

Bi-fuel impressions
The slowly developing trend toward natural gas fuel use can only be pushed further by recent announcements from Detroit's Big Three auto builders that they will soon sell "bi-fuel" gasoline/natural gas pickup trucks.