DENSO fuels interest in diesel technology at SAE World Congress news conference

Reporters from around the world gathered to hear Doug Patton, DENSO International America (standing) and Hiromi Tokuda, DENSO Corporation, discuss DENSO’s diesel common rail technology.

Dirty. Smelly. Noisy.
That’s how most North Americans describe diesel engines. The negative opinion stems from the 1970's when automakers tried, without much success, to beat the oil embargo by adapting gasoline engines for diesel fuel use.

In fact, in spite of diesel’s popularity in Europe, and its ability to boost engine power while maximizing fuel economy, a J.D. Power and Associates Clean Diesel Market Assessment Study showed that many North American consumers still have negative perceptions of diesel-powered vehicles.

Not your daddy’s diesel
DENSO has developed technology that is turning those unenthusiastic descriptions of diesel engines into terms like:
• Fuel efficient
• Clean
• Quiet
• Powerful

And we demonstrated that technology during our news conference at the 2003 Society of Automotive Engineers (SAE) World Congress, March 3-6. During the news conference, Hiromi Tokuda, director, Diesel Injection Product Division and Gasoline Injection Production Division, DENSO Corporation, and Doug Patton, senior vice president, Engineering Group, DENSO International America, discussed DENSO’s current and next-generation diesel common rail technology.

Faster, cleaner, quieter
In 2002, DENSO developed a 1,800 bar common rail diesel system that achieved a high injection pressure—1,800 bar—the highest in the world at introduction. That helps make the system faster, cleaner and quieter.

How does it work? The 1,800 bar system consists of a supply pump, a common rail with a high-pressure sensor, solenoid injectors and a high-speed electronic control unit or ECU. All of the engineering is finely detailed for specific results.

“We improved the diesel engine by improving the fuel injection system,” explained Tokuda. “So it provides higher injection pressure, better atomization of fuel with multiple fuel injections, more power, improved combustion, and a more powerful vehicle.” Not to mention a cleaner and quieter one.

The secret of our success
What makes DENSO’s common rail system so unique? Several things.

First, our 1,800 bar system uses a nozzle-tip hole reduced in size from 0.15 diameter to 0.13 diameter. Usually, the smaller nozzle reduces power as it reduces noxious emissions. But not at DENSO. We increase the fuel pressure to counter the smaller nozzle, which restores the lost power and increases the engine’s performance capability.

Second, our system employs five injections, three more than conventional common rail systems, which reduces emissions and noise and engine vibration while it increases power.

So what about the noise—the clattering and pinging we remember from the 1970s-style diesel engine? According to Patton, we’ve fixed that too.

“Existing fuel systems have what are called ‘aging factors,’ which means that the injection amounts change during the life of the engine due to use and wear,” Patton said. “The result is rough idle or engine noise. Because of our ‘learning control’ software, the injection quantities are kept precise for the lifetime of the engine, and that means smoother idle and less noise."

The results
We tested the 1,800 bar common rail diesel system in a 2.0 liter, 4-cylinder in-line intercooler turbo-equipped engine, and this is what we found. Our system:
• Increased engine torque by 35 percent.
• Increased engine power by 24 percent.
• Significantly reduced emissions of particulate matter and nitrogen oxide.
• Reduced engine combustion noise at low idle by 6.5dB (due to the five-cycle multiple injections).

As a matter of fact, the 1,800 bar system emission results meet the EURO4 regulations without a Diesel Particulate Filter—while conventional models are still stretching to meet the old, EURO3 regulations. In regard to U.S. regulations, we expect to continue to provide cost-effective solutions to government emissions requirements.

To the future and beyond
But DENSO isn’t stopping there.

“In the future, DENSO will use “piezo” injectors, which can achieve a lightning-quick response interval time of close to 0.1 milliseconds,” said Patton. “That’s a marked improvement over the current speed of 0.4 milliseconds.”

Norio Omori, DENSO Corporation (right), was awarded Fellow Grade Membership in the Society of Automotive Engineers during a special luncheon on March 4. Candidates are elected to this prestigious grade by other SAE members in recognition of achievements that have led to meaningful advances in automotive technology. SAE 2003 World Congress highlights Once again, DENSO sponsored the Media Center at the 2003 SAE World Congress. This year, we included a display on the Muran 2002: The Idea Contest. This year’s Muran third-place winner, Jeff Wetters from DENSO Manufacturing Michigan, displayed his entry—a spokeless bicycle which decreases wind resistance and increases speed. Wetters was interviewed by several journalists, including reporters from FOX 2 News in Detroit. Doug Patton, senior vice president, Engineering Group, DENSO International America, was one of four panelists discussing the pace of vehicle electronic systems development at SAE’s Technology Theater. DENSO associates presented seven technical papers on topics ranging from super ignition spark plug to electrolytic phosphating process for paint. Norio Omori, executive vice president, DENSO Corporation, was honored with an SAE Fellow Grade Membership. DENSO was presented with a 2003 Corporate Supporter award from the SAE Foundation for support of the foundation’s initiative to improve education in math, science and engineering.