Komatsu D61-23 crawler dozer has a Komatsu Tier 4-Interim SAA6D107E-2 engine that provides the same horsepower as its predecessor while lowering fuel consumption by up to 10 percent. Net horsepower is 168 at 2,200 rpm, and operating weights range from 39,099 pounds to 41,138 pounds, depending on configuration. Komatsu’s Tier 4 Interim engine platform uses an advanced electronic control system to manage airflow rate, fuel injection, combustion parameters, and after treatment functions.