Six months late according to the EPA and competitors, but right on time by its own estimation, Caterpillar has introduced its full line of truck engines for highway use. The new C7, C9, C11, C13, and C15 engines meet the standards set for exhaust emissions that were imposed by the Environmental Protection Agency on October 1, 2002. The new engines use proprietary Caterpillar ACERT combustion and exhaust treatment technology instead of exhaust gas recirculation.
Caterpillar claims that fuel economy for the new engines is equal to that of its 2001 model engines and three to five percent higher than engines using exhaust gas recirculation. The new technology utilizes an efficient combustion process built around flexible fuel injection. Electronic controls with proprietary algorithms adjust the engine to the optimum setting for reduced oxides of nitrogen emissions and maximum fuel economy. Engines in the heavy-duty line use conventional turbochargers with electronic waste gates. These are coupled with hydraulic-assist valve controls for flexible air management. The system recovers exhaust energy for improved fuel economy and lowers combustion temperature in the cylinders for reduced exhaust emissions.
The small displacement C7 and C9 engines use conventional single turbochargers. The heavy-duty C11, C13, and C15 engines use two standard turbochargers coupled in series to split the work once done by a single turbocharger. Reducing the total stress on each of the two turbochargers increases component life and using already proven waste gate technology enhances intake system reliability.