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SwRI Tries to HEDGE with Advanced Gasoline Combustion Research Program

The Southwest Research Institute (SwRI) is conducting a cooperative research program to develop a higher-efficiency gasoline engine for both light- and heavy-duty applications.

The research consortium, known as HEDGE (High-Efficiency, Dilute Gasoline Engine), seeks to develop new technologies for the gasoline engine market that will make the platform more competitive with diesel in efficiency and emissions.


The opening the group sees is the potential cost and efficiency impact that post-2010 EPA emissions goals and Euro5 emissions standards might have on diesel platforms. With improved combustion technology, the HEDGE group reasons, the gasoline engine may be able to better compete in key markets. (The chart to the right plots a cycle simulation comparison of gasoline (HEDGE) and diesel (CI) engines in medium-duty applications.)

SwRI introduced the program to a range of companies in Europe, Asia and the United States, including light- and heavy-duty engine manufacturers, component suppliers, and oil and fuel companies. Current membership includes Corning Incorporated, Cummins Engine Company Inc., Hino Motors Ltd, John Deere, Peugeot Citroen Automobiles, Volkswagen of America, and Volvo Powertrain - Renault France.

This program can serve both gasoline and diesel manufacturers, enabling each to “hedge” their bets on the direction engine technology will take in the post-2010 era. Currently, the consortium is working on energetic ignition, low-knock engine design and engine controls. The goal of HEDGE is to demonstrate gasoline engines that have efficiencies competitive with that of the diesel engine, particularly in respect to post-2010 emissions levels.

—Dr. Thomas W. Ryan III, SwRI program manager, Engine, Emissions and Vehicle Research

HEDGE projects focus on development of:

  • Knock-resistant combustion chambers

  • High-energy ignition approaches

  • Strategies for high brake mean effective pressure (BMEP) operation

The use of exhaust gas recirculation (EGR) is a key element for eliminating throttling losses and mitigating engine knock. Key features of the use of the HEDGE EGR approach include:

  • High boost

  • High BMEP

  • Model-based control

  • Intelligent, high-energy delivery ignition system development

Program participants will select the consortium work from a number of projects. Institute engineers and scientists recommend areas of interest based on SwRI’s automotive-related experience and on work initiated in the Institute’s internal research program, such as the SwRI-developed control algorithms and modified ignition and combustion concepts.

The initial meeting for the HEDGE consortium was conducted on January 27, 2005, and the second meeting was held May 25-26. Interested parties may join the program at any time. For more information, contact Ryan at (210) 522-3192, fax (210) 522-2019 or e-mail [email protected].



Ernie Rogers

SwRI is aiming at the wrong bird--

They are trying to make gasoline engines more competitive with TODAY'S diesel engines. But diesel scientists /engineers are working hard too. By the time SwRI has a gasoline engine to match performance of production diesels currently at Eff = 0.43, the diesel engine folks will have an engine nearing Eff = 0.60, AND THEIR ENGINES WILL BE ABLE TO ACCEPT GASOLINE.

Ernie Rogers


Just because you dont understand how it wors doesn't mean that SwRI are the culprits. HEDGE is a diesel operating mode that allows the compression-ignition cycle to operate with gasoline without knock, hence the high dilution rate. This is a diesel engine with high thermal and volumetric efficiency, and gasoline-like emissions.


I agree with SWRI. I think a more fuel economy not only should happen it will happen. I don't think the kind of increase will happen with the current design. The OE's have been doing the same thing over and over for years. The current head/valve package is antique. I have the cylinder head design that will give the type of air flow and compression and valve timing to change the entire design of the engine. It's all in the head design guys! I have the future engine in my garage.

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