Fuel-Efficient Automobiles
The lean-burn philosophy (editorial, “The Japan That Can Say Yes,” Aug. 1) isn’t anything new: It’s been known for years. General Motors has been researching it since the mid-1930s, and we used it in production a number of times back in the days when leaded gasoline was in vogue.
Right now, in fact, we are exploring the limits of lean combustion using a modified 2.3-liter Quad-4 engine in a 3,250-pound vehicle. The engine uses many advanced technologies and has achieved fuel economy gains of 12% to 15%. NOx emission levels slightly below 1.0 grams per mile have been measured.
Lean-burn is an exciting technology that can improve the fundamental efficiency of combustion. However, the basic problem with this technique is that it generates greater amount of oxides of nitrogen (NOx) and is suitable only for very small engines and very light cars. With current technology, it would not meet the emission regulations that will go into effect in the near future. What is needed is a new NOx catalyst.
The technical papers which Honda and Toyota presented at the Academy of Sciences workshop in Newport Beach last month made exactly the same point--a new catalyst is needed if lean-burn technology is to meet future emissions standards.
Honda’s announcement is not unlike the one it made in the early 1970s when it introduced its CVCC. That vehicle met the emissions regulations of that era, but after GM introduced its no-lead catalyst, Honda quietly removed the CVCC from production.
General Motors pioneered the catalytic converter and was the first auto maker, foreign or domestic, to install it on all its gasoline-powered cars in the United States; we also are the first to do so in Europe.
As for fuel economy, it’s interesting to note that GM cars rank No. 1 in fuel economy in more U.S. EPA classes than any other manufacturer--and hold that top rating in more than twice the number of EPA categories than do all Japanese auto makers combined.
RICHARD M. DONNELLY
Vice President, General Motors Corp. & General Manager, GM Powertrain Div.
Brighton, Mich.
