Liquid natural gas (LNG) has great potential for near-term use as an energy efficient fuel for heavy-duty vehicles. Unfortunately, low grade supply and Aweathering effects" can create composition and fuel quality problems when it is used as a vehicle fuel. An engine tuned to operate efficiently on one LNG mixture can have poor performance, high emissions, and excessive fuel consumption with another. A vehicle-based composition sensor could solve these problems. This project will develop acoustic measurement technology to determine natural gas composition on board heavy-duty LNG-fueled vehicles, resulting in a low-cost natural gas composition sensor. In Phase I, a sophisticated acoustic test cell was designed and built to perform laboratory-based acoustic measurements of acoustic attenuation at various frequencies and pressures. The test cell included a precision gas blending system, supporting electronics, and a high pressure acoustic test chamber. Several different samples of natural gas were measured, and the underlying physics of acoustic attenuation was investigated. Phase II will expand testing, develop predictive algorithms, and develop a prototype sensor with acoustic transducers that will measure the attenuation, sound speed, and impedance of natural gas as it flows toward the engine. The output from the sensor will be fed to signal processing electronics in a separate enclosure that would transmit the natural gas composition data to an engine controller.
Commercial Applications and Other Benefits as described by the awardee: An acoustic natural gas composition sensor could transmit natural gas composition data to an engine controller, allowing heavy-duty vehicles to utilize LNG fuels of varying mixtures. Its development should lead to reduced emissions, better performance, and lower fuel consumption.
