Westport unveils proprietary enhanced spark-ignited natural gas system

Westport Innovations Inc. unveiled the first generation of its new, proprietary enhanced spark-ignited (ESI) natural gas system. The new approach to natural gas combustion technology is designed to provide vehicle and engine original manufacturers (OEMs) with a “downsized” natural gas solution that is cost competitive while providing similar levels of power, torque, and fuel economy to a larger diesel engine.

Using 100% dedicated natural gas as fuel, Westport’s new technology optimizes the combustion and thermal efficiencies of the engine by taking advantages of the positive properties of natural gas. The Westport ESI combustion system is targeted at sub 9L engines for Class 6 and 7 trucks applications and is also adaptable for sub 2L applications for use in automotive and non-automotive applications.

Key features of the Westport ESI system include:

  • Optimized for spark ignited engines: Improvements in combustion and thermal management compared to typical spark-ignited natural gas engines ultimately enhance the engine’s reliability.
  • Designed to provide up to 10% improvement in power and torque over the base diesel engine: Higher performance from a spark-ignited natural gas engine compared to a diesel engine potentially allows a 4L natural gas engine to replace a 6L diesel engine, which results in substantial mass reduction.
  • Comparable fuel economy to diesel engine: By taking advantage of the positive properties of natural gas—for example, natural gas has less calorific energy compared to diesel—Westport believes that it is able to improve the fuel economy of a typical spark-ignited natural gas engine. In addition, cooled exhaust gas recirculation (EGR) is applied, which is a well known mechanism for improving fuel efficiency, used extensively in passenger vehicles.
  • Designed to provide up to 40% brake thermal efficiency: Typical spark ignited natural gas engines have approximately 25-30% brake thermal efficiency and diesel engines have approximately 41% brake thermal efficiency.
  • Designed to provide up to 5% weight reduction compared to the base diesel engine: Weight is a critical element for truck fleets, so any reduction in engine weight equals an increase in payload.
  • Fuel injection: The current system utilizes port injection providing better cylinder-to-cylinder control of the air-fuel ratio. However, it is designed for upgrades to future technologies.
  • Incorporates key Westport engine components: This includes Westport WP580 Engine Management System and Westport fuel system components.
  • Stoichiometric operation and three-way catalyst (TWC) aftertreatment: TWCs are effective, simple devices, packaged as part of the muffler, that provide consistent emissions control performance and are maintenance-free. By using 100% natural gas, there is no requirement for diesel particulate filter (DPF) or selective catalytic reduction (SCR) systems. This allows cost and weight reduction over base diesel engine.
  • Euro VI and EPA 2014: Westport ESI is designed to meet the latest emission regulations including Euro VI and U.S. Environmental Protection Agency 2014 standards.
  • Compressed natural gas (CNG) or liquefied natural gas (LNG) capability: Every natural gas engine burns CNG. Ultimately, the customer will decide which form of natural gas they wish to carry—either high pressure CNG or cold cryogenic LNG—based on a number of variables including but not limited to: weight of the load; weight of the fuel storage system; range required by the vehicle; and availability of CNG and LNG.

Westport’s new combustion system and components have been undergoing testing and offer ready integration into OEM applications globally. Westport expects the durability and reliability levels to meet an OEM’s extensive engine development program.

As gasoline and diesel engines progress, it is critical that OEMs offer natural gas engines that retain their expected performance while providing the environmental and economic benefits of natural gas. Westport is taking its technology leadership to the next level by introducing a long term technology solution that allows improvements in engine performance and fuel economy, thus offering highly attractive operating costs and low emissions profile. As the ESI technology continues to be developed, Westport will incorporate competitive performance upgrades to support the longevity of this system.

Westport says it is currently in various stages of development and negotiation with several vehicle and engine OEMs for ESI applications in medium-duty truck and automotive applications.