Westport announces Gas Enhanced Methane Diesel (GEMDi) technology

12 February 2014

Westport Innovations announced a fumigated dual fuel engine technology, called Westport “gas enhanced methane diesel” (Westport GEMDi). In-line with the new business strategy of Westport, the GEMDi technology is intended for original equipment manufacturers (OEM) to offer a fully integrated engine optimized for dual fuel operation.

Westport GEMDi technology has been co-developed with Tata Motors on their next generation 5 L engine that is targeted for medium-duty trucks and buses in India. This technology provides fuel flexibility ideal for regions where natural gas infrastructure is emerging, such as India, and is designed to meet Euro IV and V emission standards.

The GEMDi technology is based on conventional dual fuel approach utilizing fumigated natural gas induction. It does not include the Westport high pressure direct injection (HPDI) hardware.

A dual fuel engine typically relies on conventional diesel engine, modified to allow operation with natural gas. In fumigated dual fuel engines, natural gas is mixed at low pressure with the intake air. Diesel fuel—introduced directly into the combustion chamber near the end of compression stroke—is used to ignite a lean mixture of natural gas and air. Dual fuel engines can provide higher performance (torque and power) and efficiency on natural gas fuel as compared to a traditional spark ignited natural gas engine. Based on Westport analysis, typically a dual fuel vehicle would operate at about 60% average fuel substitution ratio, with the remainder coming from diesel fuel. Higher fuel substitution ratios are possible through improved engine design and control. Dual fuel engines are capable of reverting back to 100% diesel operation over the entire engine operating range if required.

The Westport HPDI technology, on the other hand, involves injection of both natural gas and diesel directly into the combustion chamber, utilizing a specialized HPDI dual fuel injector. Compared to fumigated dual fuel technology, the HPDI can offer better tolerance to knock and better performance, as well as higher natural gas fuel substitution ratios, at the expense of the added cost of the HPDI hardware.

Tata's 5 L natural gas engine featuring Westport GEMDi was displayed at India’s Auto Expo in New Delhi, India. Upon successful completion of the development phase, commercialization with Tata Motors is expected to follow, with Westport supplying key natural gas engine components, said the company.

Westport and Tata Motors also launched a new spark ignited (SI) natural gas 3.8 L turbocharged engine featuring Westport WP580 Engine Management System (EMS).

India is one of the world's largest truck and bus markets. Its total annual medium- and heavy-duty truck and bus sales are projected to reach over 289,000 units in 2014 and 478,000 units in 2022, according to the Natural Gas Trucks and Buses report published by Navigant Research. Tata's 5 L engine with Westport GEMDi technology is primarily targeted for medium-duty trucks and buses running on dedicated routes in India. According to Navigant Research and Westport analysis, India’s medium-duty natural gas truck and bus population is projected to be over 12,000 units in 2014, representing a 5% market penetration, and is expected to grow to more than 60,000 units in 2022, reaching a 15% market penetration in the medium- and heavy-duty truck and bus market.

Source: Westport