Change is in the air for older diesel engines

There are thousands of hard-working older vehicles out there in America's fleet of about 7-million commercial trucks, honorable veterans of many loads and many miles. Also-aging mechanical engines, built before vehicle exhaust emissions became a global concern, power lots of these trucks, however, and that's fast becoming a brand-new problem.

At the state, local and federal level the pressure is growing to clean up the emissions from these older vehicles to amounts more in line with today's electronic engines and with tomorrow's emissions regulations. The EPA, for example, recently announced a new, voluntary initiative called "The Diesel Retrofit Program," designed to encourage fleets and others to reduce the emissions from at least 10,000 older engines over the next two years.

Even though the agency hopes to work with state governments and other organizations to provide financial incentives, the task is still daunting. First of all, some older engines produce almost twice as much NOx (oxides of nitrogen) per brake horsepower hour as today's newer engines and far more than the pending 2002 limits. Then there's the soot issue, the high-visibility problem of hydrocarbons and particulate emissions from older diesels. How do you clean up emissions at this level without sacrificing vehicle performance or breaking the bank?

"Just park them" is one gloomy alternative, but other promising solutions are emerging. At Seattle-based Timing Systems, for example, independent testing has just been completed on a new diesel fuel injection timing system dubbed "TS-100D." The patented device is designed to dramatically clean up the emissions from pre-1990 mechanical engines while also improving overall performance and fuel economy, according to James C. Paul, a partner in the firm.

"The TS-100D injection pump connects to the engine via a coupling unit," explains Paul. "The system changes injection timing by rotating the injection input shaft and the engine output shaft in relation to each other. An electric motor activates the TS-100D, and a transfer device translates the vertical force from the electric motor into lateral movement in the coupling. The result is improved engine performance and lower emissions."

According to Paul, the next step is to move out of the lab and onto the highway to verify test results in the real world. Additional independent testing and certification is also currently in the works. "I hope we'll see units going into production by this time next year," he says.

Meanwhile, in California an entirely different approach to reducing diesel emissions in new and in-service trucks and buses is also well under way. Ceryx manufactures a proprietary catalytic converter called the QuadCAT Four-Way Catalytic Converter. The company says it is the only catalytic converter presently available that simultaneously reduces four of the major sources of air pollution - NOx, hydrocarbons, carbon monoxide and particulate matter - to levels that will allow diesel engines to meet 2002/2004 emissions standards.

The converters are currently undergoing certification testing; full-scale production is expected to begin this fall.

For fleets, the timely entry of new technologies such as these into the marketplace is encouraging. Just when it looks like a storm may be brewing over the continued operation of older trucks, technology is helping to clear the air.