Caterpillar says its new D6T, D7E and D8T bulldozers feature engine and aftertreatment solutions to meet U.S. Environmental Protection Agency Tier 4 Interim emissions standards.
The D6T and D7E use Cat’s C9.3 ACERT engine and the D8T uses the C15 ACERT engine, having net horsepower ratings of 205, 235 and 310, respectively. These engines employ Cat’s NOx Reduction System and Clean Emissions Module (CEM) to meet current emissions standards. The NOx Reduction System continually diverts and cools a small volume of the engine exhaust gases and then returns the cooled gases to the combustion chamber. This process reduces cylinder temperatures and, consequently, lowers NOx formation. The CEM, a compactly packaged aftertreatment unit, includes a Diesel Oxidation Catalyst and a Diesel Particulate Filter (DPF) to remove particulate matter from the exhaust stream. Also included is the Cat Regeneration System—a process that removes soot from the DPF. The D6T, D7E and D8T each offer optional Key Off Regeneration, as well as a delayed engine shutdown timer and an engine idle shutdown timer. For applications that require thermal shields on exhaust components, an optional insulated CEM will be available in mid-2011.