|NorCal’s First-Generation HPDI LNG trucks|
The City of San Francisco and Norcal Waste Systems Inc., the city’s refuse collection, recycling and transfer company, will deploy and demonstrate Westport’s second-generation High Pressure Direct Injection (HPDI) LNG technology for heavy-duty trucks in a pilot program through 2011.
This will mark the first deployment of the new HPDI technology in heavy-duty trucks in the US. Westport is using HPDI in a major pilot program in Canada (earlier post) and has proposed an even larger program for China (earlier post).
Goals of the program include improving combustion and reducing greenhouse gas emissions.
As part of its commitment, SF Recycling & Disposal, a Norcal subsidiary, will upgrade three of its 13 heavy-duty transfer trucks currently operating on Westport’s first-generation HPDI technology.
The new trucks will incorporate several major improvements over those first-generation vehicles, including enhanced vehicle performance, lower emissions, higher fuel economy, and reliability.
New features include Westport’s proprietary low heat-leak LNG tanks with integrated LNG pumps, and higher pressure improved common-rail injection system for better combustion and emissions at all operating conditions.
Since they were first put into service in 2001, the first-generation LNG transfer trucks have logged almost five million miles (eight million kilometers) and reduced fleet emissions by approximately 30 tons.
Over the course of the new LNG powered truck program, the trucks will save an estimated total of approximately 70 tons of emissions.
The truck upgrades will feature new 400-hp Cummins ISX engines equipped with Exhaust Gas Recirculation (EGR) and Westport’s second-generation HPDI fuel system fuelled by LNG.
High Pressure Direct Injection relies on late-cycle high-pressure injection of natural gas into a cylinder. Natural gas has a higher ignition temperature than diesel (1,000° C vs. 500° C) and will not easily ignite at the temperatures and pressures in the combustion chamber of a normal diesel engine. To assist with the ignition of natural gas, HPDI precedes the main gas injection with a small injection of diesel fuel and using the same dual-concentric needle injector.
In this second-generation version of HPDI, Westport is increasing the injection pressure, using more EGR and increasing control of air handling in the engine. The new system also uses an improved LNG pump, and more robust HPDI injectors. The combination of all of that is designed to improve efficiency, and to support higher-power engines of up to 450-hp.
The three trucks will be certified at the California Air Resources Board 2007 emissions levels for NOx and PM, and are supported by a previously announced award from the US Department of Energy’s National Renewable Energy Laboratory (NREL).
The Westport-equipped transfer trucks operating at Norcal make up to six 120-mile round trips per day from the company’s transfer station on the outskirts of San Francisco to the Altamont landfill site. Each truck operates at a gross vehicle weight of 80,000 pounds.
Collectively, Norcal subsidiaries operate a fleet of approximately 1,100 vehicles. The companies provide solid waste management and recycling for more than 400,000 residential and 50,000 commercial customers in San Francisco and more than 50 other communities in California.