Natural gas truck engine producer Westport Innovations plans to stop taking orders for its North American 15-liter model after Nov. 15.

The development was disclosed in the company’s latest earnings report, released Oct. 30, in which it reported a net loss of $30.2 million dollars in the third quarter of the year, down slightly from a $32.5 million loss in 2012.

Speculation started nearly a month ago that Westport was abandoning its 15L LNG model, which is the only 15-liter natural gas engine for trucks available in North America.

Sales of the model have reportedly been weak, with only around a thousand sold, since it hit the market several years ago.

It uses a combination of Westport’s HPDI (high-pressure direct injection) natural gas technology with a Cummins ISX model long block.

“Westport on-road business strategy is to provide HPDI  as a vertically integrated solution for engine and truck OEMs. The current generation of HPDI on the Westport 15L engine is still assembled in Vancouver [British Columbia using an upfit process. Westport's production focus is shifting from an upfit model to vertical integration of Westport's next generation of HPDI for targeted OEMs,” the company said in its earnings report.

Westport says it will continue to offer the 15-liter model for trucking customers in Australia for the “foreseeable future.”

Last year, Westport announced it was working to develop a 13-liter heavy duty natural gas engine for North America with Volvo that is expected to launch next year.