Isuzu signed a $1.5 million deal with Westport for the design and construction of two next-generation CNG-DI (Compressed Natural Gas Direct Injection) ELF trucks to be delivered in 2005.
Conventional CNG-powered engines use spark ignition—the standard gasoline-engine approach to combustion. Using CNG as a fuel in such an engine makes it possible to achieve virtually zero PM emission, while NOx emission can be drastically reduced as well. When it comes to the thermal efficiency of the engine however, the CNG-powered engines are equivalent with gasoline-powered and slightly less efficient than conventional diesel engines.
By comparison, the direct injection CNG engine adopts a standard diesel compression ignition approach. It does not mix air and fuel in the intake or the compression cycle to then be ignited with a spark, but injects the fuel into the cylinder while and after the piston compresses the air to be ignited by the heat of compression. The result is better thermal efficiency, power, and range than standard natural gas engines deliver as well as superior emissions performance.
Isuzu and Westport collaborated on the first-generation CNG-DI platform that produced the world’s first-ever direct-injection, diesel-cycle, CNG-powered light duty truck. This prototype CNG-DI truck successfully won two gold awards and one silver award at the 2003 Michelin Challenge Bibendum competition for excellent fuel economy, ultra low exhaust emissions, and low vehicle noise.
In the first generation ELF CNG-DI, Isuzu used a 4.5-liter, in-line four engine as the base and enhanced it with a variable turbocharger and a variety of emissions reductions technologies (Exhaust Gas Recirculation (EGR), oxidizing catalytic converter and a urea SCR catalyst for NOx reduction).
The new vehicles will continue to combine Westport’s electronic, directly actuated, high-pressure natural gas fuel injectors, on-board compressor system, electronic controls and hot surface ignition system (also known as a glow plug) with Isuzu’s diesel technology. The goal of the second generation work will be to increase combustion control and engine efficiency, increase range and further reduce emissions. The cooperative development work will be performed both at Westport’s engine laboratory in Vancouver, Canada and Isuzu’s engine laboratory in Fujisawa, Japan.
“At Isuzu, we believe that the direct injection technologies we are advancing with Westport represent the future of natural gas fuel systems providing the high thermal efficiency and ultra-low exhaust emissions our customers will require. We are also studying the prospect of applying these systems to Isuzu’s full-range of trucks and buses,“ said Mr. Takashi Urata, Executive, Powertrain Engineering at Isuzu in Tokyo.
As we’ve noted here earlier, the Japanese government is fully endorsing increasing CNG usage in transportation. Beginning early in 2005, the Ministry of Land, Infrastructure and Transport (MLIT) will promote CNG vehicles in the cities of Tokyo, Nagoya, and Osaka, set up public and private initiatives to establish more CNG fuelling stations, expand subsidies for CNG vehicles, and lower CNG prices. There are currently 270 fuelling stations for 20,000 operating CNG vehicles in Japan.
Isuzu Motors Limited is one of the world’s leading manufacturers of commercial vehicles and diesel engines, and has manufactured more than 17 million diesel engines. GM holds a 12% stake in Isuzu, and the two have established a new joint venture company called GMI Diesel Engineering Ltd.(GMIDEL) for powertrain systems. The Isuzu ELF is Japan’s best-selling light-duty truck.