Itabashi, S., Murase, E., Tanaka, H., Yamaguchi, M. et al., "New Combustion and Powertrain Control Technologies for Fun-to-Drive Dynamic Performance and Better Fuel Economy," SAE Technical Paper 2017-01-0589, 2017, doi:10.4271/2017-01-0589.
Toyota Motor Corporation has developed a new series of engines under the Toyota New Global Architecture (TNGA) design philosophy, which aims to satisfy customer requirements for both fun-to-drive dynamic performance and better fuel economy by adopting a high-speed combustion concept to improve thermal efficiency and specific power. This new engine series achieves a maximum engine thermal efficiency of 40%, a specific power ratio of 60 kW/l, and lower emissions by combining high-speed combustion and a high compression ratio with a high-tumble intake port, high-energy ignition coil, high-pressure multi-hole nozzle direct injector, and new electrical variable valve timing (VVT). The first engine in this series is a new 4-cylinder 2.5-liter gasoline naturally aspirated engine for use in passenger cars alongside a new TNGA 8-speed automatic transmission, which was introduced for minivans and SUVs in the U.S. market in 2016. This TNGA powertrain system realizes top-class fuel economy with a direct and smooth acceleration feeling in ordinary driving situations by combining a new drive force (DF) demand control system with vehicle acceleration behavior targets.