Chevrolet will continue to work with a second-stage manufacturer to offer a single-source option for its NGVs. The bi-fuel trucks are built with the specially designed engine, the fuel system is installed by GM’s Tier One supplier, and the completed vehicle is delivered directly to the customer. This process makes ordering the bi-fuel option as seamless as ordering a truck powered by gasoline or diesel, and ensures the highest level of durability, reliability and safety.
In addition to the gasoline and Duramax diesel powertrains, the new 2015 GMC Sierra HD lineup is also including a bi-fuel option that pairs the gasoline engine with a compressed natural gas system. This variant features special hardened valves and valve seats that enable it to run on CNG or gasoline. The CNG fuel system is also installed by a GM supplier and completed vehicles are delivered directly to the customer.
Source: General Motors