Freightliner's new truck, Revolution

[mechman600]

Horsepower hasn't risen much since the mid 1990s. Maybe in heavy haul, but the average line-haul truck is still 425-475 HP, 1550-1650 ft/lb torque, same as the last 15 years. It is the stringent NOx emissions limits that has forced engine manufacturers to produce engines that are simply less efficient. Combustion temps have been lowered with the aid of timing changes (initially), EGR (later) and advanced charge air cooling methods (Caterpillar) so less NOx is produced. I have dynoed early 90's N14s where the exhaust manifold was glowing red at full load. Before SCR came out in 2010, manufacturers were going so far with EGR that you could barely get 800F turbo out temps. At least now SCR aftertreatment takes care of most of the NOx reduction, so engines can be tuned for more efficiency, so it is getting better....at the expense of ridiculous complexity.