In the December edition of eNews, the NAFTC's "Lets Clear The Air" column provided details of the Cummins-Westport ISX truck engine, which utilized a dual fuel injection system utilizing high CNG pressures obtained by storing and compressing the fuel as LNG.

In March, the California Air Resources Board (CARB) announced that it has certified the HPDI system as meeting CARB emission standards, thus making it available to commercial fleets in California. The CARB standards require that exhaust emissions not exceed 1.2 grams per brake horsepower per hour of NOx (and HCs) and 0.02 grams per brake horsepower per hour of particulates. The ISX series diesel/LNG/CNG-fueled engine is available either as a 400 HP unit or a 450 HP version, which produces 1650 ft/lbs of torque.

Fuel companies and governmental agencies are working to facilitate easy availability of the cryogenic fuel needed by this system. These include Clean Energy Fuels Inc. of Seal Beach, California, and the South Coast Air Quality Management District, which has supported the development of the Cummins-Westport system for several years.

Cummins-Westport officials anticipate strong sales of the HPDI, especially in the Los Angeles basin where there is a high proportion of older trucks causing excessive emissions. However, cost figures have not yet been announced.