Clean Diesel Technologies Inc. Announces Latest Test Results of Platinum Plus Diesel Fuel Additive.

STAMFORD, Conn.--(Business Wire)--May 13, 1998--

Additive Improves the Performance of Diesel Soot Filters, Lowers

Emissions by 95 Percent at Cost of $0.02-$0.05/Gallon

Clean Diesel Technologies Inc. (Nasdaq:CDTI) Wednesday announced that results of extensive tests of its platinum/cerium bimetallic diesel fuel additive at Delft Tecnical University, Netherlands, will be presented at the 22nd CIMAC Congress on May 19 in Copenhagen.

Testing at Delft has helped to understand the fundamental catalytic mechanisms by which the additive substantially improves the performance of diesel soot filters which can remove more than 95 percent of the soot particles emitted from diesel engines.

Researchers at Delft and CDT have identified a novel approach which uses extremely low levels of a bimetallic platinum/cerium fuel additive and a lightly catalyzed soot filter to reduce the oxidation temperature of soot by over 200 degrees Celsius to temperatures as low as 310 degrees Celsius. Temperatures in excess of 540 degrees Celsius are normally required to oxidize soot collected in diesel particulate filters. This was accomplished at metal treatment rates as low as 5 ppm, which is one or two levels of magnitude lower than other metallic fuel additives. Based on comparison of the Platinum Plus bimetallic additive against several other trap regeneration systems, the report concluded in part that: -0-

"A combination of a Corning Cordierite monolithic filter, Corning EX80 or EX47, and a Platinum/Cerium fuel additive results in stable operation for soot collection and continuous regeneration from temperatures of 583 K (310 degrees Celsius) and higher. This is superior in performance to any system known yet." and "The metal concentrations needed for sustained operations can be as low as 0.5 ppm of Platinum and 5 ppm of Cerium."

CDT noted that even lower levels of additive are likely to be used in practice, but these lower levels were not evaluated in the program at Delft.

"The work at Delft gives us a fundamental understanding of the catalytic synergy between platinum and cerium and helps explain the excellent success we have had with this system in full scale engine tests and field demonstrations," stated James M. Valentine, chief operating officer of CDT.

Diesel soot emissions are coming under increasingly more stringent regulations in the United States, Europe, and Japan. CDT has already initiated cooperative development programs with several heavy duty and light duty engine manufacturers in the United States and Europe and filter/additive systems are expected to be in use in Europe as early as year 2000 on new passenger diesels. Many urban areas are looking to these systems to reduce emissions from existing buses and trucks.

Diesel soot filters are a proven technology for removing soot emissions from existing and new vehicles, but they will quickly plug with soot unless a method to efficiently oxidize the soot is applied. While burners and electrical heaters have been used to raise temperatures in the filter, engineers generally agree that a "passive" means is more economical using either a catalyzed filter or a metal combustion catalyst added to the fuel. In either approach, the catalyst lowers the oxidation temperature of soot collected in the filter and "passively" regenerates the filter.

Catalyzed filters, however, suffer from high initial cost, poor long-term durability and a tendency to form unwanted sulfate by-products due to the high level of catalyst applied initially to the filter surface. Thus, their application has been limited to use with ultra-low sulfur fuel which has higher cost and is generally unavailable in most parts of the world. As an alternative to catalyzed soot filters, fuel additives such as iron, cerium and copper have been used to catalytically activate the soot, but due to their low catalytic activity must be used at levels of 50-125 ppm of metal in the fuel. This high level of metal can lead to engine wear and build up of metallic ash residue in the filter. These additives generally lower the soot oxidation temperature by only 80-120 degrees Celsius which can lead to runaway temperatures in the filter when the soot ignites under high engine load conditions.

"Late last year we completed full scale engine testing with a major U.S. engine manufacturer which documented the ability of our Platinum Plus bimetallic additive to assist an advanced heavy-duty diesel engine equipped with a soot filter in achieving the EPA 2004 diesel engine emission standard for NOx and particulates. Emissions levels of 2.2g/bhp-hr HC + NOx and 0.01g/bhp-hr particulate were achieved in engine bench tests.

"These are well below the year 2004 emission standards of 2.5g/bhp-hr and 0.1g/bhp-hr established by the U.S. EPA. The work at Delft has given us further understanding and insight as to how to maximize the system performance in the U.S. field trials planned for later this year," said Valentine.

Previous testing has also shown that the additive alone can reduce gaseous and particulate emissions from diesel engines by 15-30 percent and that its use with aftertreatment devices such as oxidizers and filters can give increasingly higher levels of reduction from both existing and new engines, in the range of 70-95 percent. Thus the additive can serve as a base in marketing a clean diesel fuel for low cost emission reduction now and will assist advanced control technologies as they are deployed.

The additive is easily blended with the bulk fuel supply or dispensed through on-board dosing and metering systems already developed by engine manufacturers. Cost is expected to be in range of $0.02-$0.05 per gallon of fuel treated once production volumes increase.

Clean Diesel Technologies is a development-stage company with patent-protected products that reduce emission from diesel engines while simultaneously improving fuel economy and power. R&D efforts and products are grouped into two categories: Platinum Fuel Catalysts and NOx Reduction Systems. Platinum Plus is a registered trademark of Clean Diesel Technologies Inc. -0-

Certain statements in this news release constitute "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements involve known or unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the company, or industry results, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof.

CONTACT: Allen & Caron Inc.

Mark Alvino (investors)

212/698-1360

Owen Daley (media)

949/252-8440

or

Clean Diesel Technologies Inc.

James M. Valentine, COO

203/327-7050