A fter two years of significant technological investment, Caterpillar Inc. on March 19 unveiled a unique breed of on-highway diesel engines at the University of Louisville in Kentucky. According to product engineers, the design breaks from conventional methods for reducing diesel gas and particulate emissions, a primary concern of environmental regulators. "We have achieved efficient combustion, with low emissions and improved fuel economy," said John Campbell, director of on-highway engine products for Caterpillar Power Systems, located in Mossville, Ill. The calls the technology ACERT, or Advanced Combustion Emissions Reduction Technology., ACERT represents the largest and most expensive product development effort in the company's 75-year history, says James Parker, Caterpillar vice president in charge of power systems. Although he declined to say how much specifically the manufacturer has spent thus far on emissions R&D, he said it was "not more than $1 billion."