Copyright jalopnik
While several factors played into making Caterpillar quit making truck engines, the cost implications stood out. The company had spent well over $500 million on developing the system. As Jim Parker, Caterpillar's vice president of engine marketing, told Construction Equipment at the time, "It has been the most expensive, largest development program Cat has undertaken. We've spent more on it than on development of the high-drive tractors." And even though ACERT engines met the tough emission rules (the rules would only get tougher later), Caterpillar had to repeatedly rework its engines. Each new EPA phase meant fresh engineering, testing, and compliance costs on top of the massive investment already sunk into ACERT. The 1990 Clean Air Act amendments became a cycle of escalating expenses. Initial limits applied to 1994 models with stricter thresholds for 2004, and even tougher benchmarks set for 2007 and 2010. By the mid 2000s, Caterpillar's on-highway truck engines made up only a small portion of its total business. Caterpillar's 2008 annual report stated that on-highway engines made up about 8% of its entire engine production. In 2010, Caterpillar realized the system was unsustainable and left the on-highway truck engine business. The company refocused on off-highway markets like construction, mining, and industrial power.
