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The Future Of Cummins, Ford and GM Diesels

We explore diesel technology from The Big Three and the U.S. Department of Energy expected to arrive by 2015.

Text By Jason Thompson, Photography by Courtesy of the Department Of Energy

The primary mission of the U.S. Department of Energy's Vehicle Technologies Program is to reduce the 13.7 million barrels of petroleum our country burns each day for our transportation needs. Why is that important? Our country's economic, political, and military strength is directly connected to our energy independence, which would be at a great advantage if our vehicles got more miles per gallon.

One of the Department of Energy's methods is to help the manufacturers increase the thermal efficiency (work out, divided by fuel in) of diesel engines from around 30 percent (found in today's vehicles) to 50 percent by 2015, and 55 percent by 2018. Some of these energy-conserving technologies are gradual changes to traditional designs, while others are more drastic. Today, gasoline engines (at 25 percent thermal efficiency) are the main drivers of the U.S. transportation system, and a switch to diesel in our consumer sector would be the easiest way to cut back on our use of foreign oil.

Cummins' goal was to improve the thermal efficiency of the 15.0L ISX and 6.7L ISB while still meeting the EPA's 2010 emissions standards and being B20 compatible. Oak Ridge National Laboratory, Purdue University, and BP helped with fuel sensing technology that virtually offsets the fuel consumption penalty of biodiesel. The team also found that a fuel blend of diesel and gasoline is desirable for advanced ignition strategies such as premixed controlled compression ignition (PCCI). Possible additions to future 6.7L diesel engines include: compound turbochargers with a high-pressure variable-geometry (VGT) exhaust housing, a variable-displacement oil lubrication pump, and piezo injectors capable of 31,900 psi and seven injection events. The heavy-duty Cummins ISX 15.0L engine is projected to receive variable valve actuation, an injection system capable of 37,700 psi, and thermal management insulation. Chrysler and PACCAR were also involved with vehicle packaging and demonstration models. Cummins spent $4.3 million (matched by the DOE) on its waste heat recovery program (for an in-depth look check out "Cummins Steam Engine," Oct. '08) and $2.4 million (matched by the DOE) on the advanced high-efficiency clean-combustion program.

Ford put $1.5 million (matched by the DOE) into research focusing on advanced turbo systems and sophisticated injection strategies for its future diesel engines. According to Ford, 20 to 40 percent of the engine's power is used to drive the turbocharger in today's boost-dependent engines, so efficiency gains in this area would have a high payoff. In this particular study (in which Wayne State University was a partner), Ford looked at how heavily cooled EGR negatively affects turbo efficiency. Unfortunately, Ford summarized that challenging a relatively matured technology turns out to be much more difficult than anticipated. The improvements to the turbo system only netted a 2- to 3-percent increase in fuel economy. On the bright side, this peer review, dated June 10, 2010, announces that the innovations gleaned from their research efforts will go into a small, turbocharged, light-duty diesel of less than 5.0L. Diesel Power speculates that one of the reasons for the 1/2-ton diesel delay was because these engines were testbeds for the different manufacturers trying out their most advanced technologies.

By Jason Thompson
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