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Westport High Pressure Direct Injection Technology
Westport HPDI technology uses natural gas as the primary fuel along with a small amount of diesel as a pilot ignition source, or "liquid spark plug."
At the heart of the engine is a revolutionary patented injector with a dual-concentric needle design. It allows for small quantities of diesel fuel and large quantities of natural gas to be delivered at high pressure to the combustion chamber. The natural gas is injected at the end of the compression stroke. Under the pressures found in the combustion chamber of a normal diesel engine, natural gas requires a higher ignition temperature than diesel. To assist with ignition, a small amount of diesel fuel is injected into the engine cylinder followed by the main natural gas fuel injection. The diesel acts as a pilot, rapidly igniting the hot combustion products, and thus the natural gas. HPDI replaces approximately 95% of the diesel fuel (by energy) with natural gas.
Above all else, Westport HPDI technology is the only engine technology that maximizes natural gas use while maintaining equal horsepower, torque and efficiency characteristics of a diesel-fueled engine.