Shareholders told license negotiations are underway.

ANNAPOLIS, Md.--(BUSINESS WIRE)--Dec. 5, 1995--Sonex Research Inc. (OTC Bulletin Board Symbol "SONX") reported in a letter to its shareholders yesterday that negotiations are underway with a major manufacturer of large diesel engines for licensing, technology transfer and further development programs for the Sonex ULTRA CLEAN BURN(TM) emissions reduction piston technology.

In their letter, Dr. Andrew A. Pouring, CEO, and Peter Y. Mills, president, said that the company recently presented its initial proposals to senior engineering and business development personnel at a major worldwide manufacturer of diesel engines, and expect to return for more substantive negotiations early next year. (Secrecy and non-disclosure agreements, which reflect the intense competitive pressures within the industry, prohibit Sonex from releasing the name of this manufacturer.) They also noted that this manufacturer is reporting positive results in its evaluation of pre-production finished Sonex pistons fabricated by the manufacturer's own piston supplier.

Sonex reports that it has achieved substantial improvements over the last three years in the levels of emissions reductions obtained with the continuing refinements in the design of Sonex pistons. Today, at equal NOx, Sonex is averaging reductions in soot and particulates of greater than 40% with fuel penalties of less than 1.5% on European emissions tests. Diesel-fueled Sonex engines would require only a piston change to provide a low emission result.

The company's executives also reported that last week Sonex conducted successful performance acceptance trials for personnel from the U.S. Naval Research Laboratory (NRL) in Washington, D.C. in connection with a purchase order from NRL for the fabrication and demonstration of two lightweight, 2-stroke, spark-ignited, carbureted (originally gasoline fueled), aircooled engines to be fueled with JP5/JP8 standard military fuel. Sonex reports that its engine showed a major improvement in fuel economy over the original gasoline fueled engine. NRL is considering this technology for its possible application in small, remotely piloted surveillance aircraft.

Sonex has also completed its work on alternate-fueled engines under a contract from the National Renewable Energy Laboratory Division (NREL) of the Midwest Research Institute, which is the field manager for the U.S. Department of Energy (DOE) Alternative Fuels Utilization Program. Sonex successfully demonstrated its technology on a one liter per cylinder diesel engine running on a number of different fuels including methanol, ethanol, biofuel and diesel, and is now awaiting NREL's approval of the project's final report.

As a follow-up to the work with NREL, in recent weeks the company has held discussions with key DOE personnel who are interested in further investigation of the Sonex alternative fuel technology. Present ideas are focusing on a public demonstration of the Sonex technology, using neat M100 methanol and other fuels in a standard diesel engine at standard compression ratios, through a joint program involving Sonex, DOE and a major oil company.

In closing their letter, Dr. Pouring and Mills told the shareholders that they believe that the Sonex ULTRA CLEAN BURN(TM) piston technology will likely become a part of future DITCI diesel engines because it is complementary to the cooled Exhaust Gas Recirculation (EGR) systems and the large variety of injection systems likely to be introduced in the near future. The Sonex executives also expressed their optimism that the negotiations for commercial agreements can be concluded successfully in the not-too-distant future.

Sonex Research Inc., a leader in the field of combustion technology, has its ULTRA CLEAN BURN(TM) technology protected by numerous patents issued and pending worldwide. The technology has been independently tested by manufacturers and has been shown to reduce emissions, enable the use of alternate fuels, permit an engine to operate on ultra-lean air-fuel ratios, and suppress knock in bench engine tests conducted in the laboratory.

CONTACT: Sonex Research, Annapolis

Peter Y. Mills, 410/266-5556