The New Inline 4 Cylinder 2.5L Gasoline Engine with Toyota New Global Architecture Concept

Authors

T. Toda, M. Sakai, M. Hakariya, T. Kato, Toyota Motor Corporation, Aichi, Japan

Year

2017

Print Info

Fortschritt-Berichte VDI, Series 12, No 802

Summary

In October 2015, Toyota Motor Corporation published “Toyota Environmental Challenge 2050“, which consists of 6 challenges, to contribute towards a sustainable society. Challenge 1 is “New Vehicle Zero CO₂ Emissions Challenge“, where the target is to reduce vehicle CO₂ emissions by 90% in comparison with 2010 levels by 2050. To accelerate this challenge, Toyota has been developing the new engine series for lower fuel consumption, higher performance and globally better productivity based on “Toyota New Global Architecture (TNGA) concept“. The new inline 4 cylinder 2.5L gasoline naturally aspirated (NA) engine is the first massproduced TNGA engine. In order to realize the higher specific power with lower fuel consumption and exhaust gas emissions, a further improvement in combustion was needed. For this purpose, the fundamental structure such as stroke-bore ratio, valve layout has been completely redesigned. As an example, the laser cladded intake valve seat has been adopted to increase both tumble ratio and air flow coeffiency. In addition, the Atkinson cycle using new electrical VVT, D-4S (direct + port injection) system with new multi-hole type DI injector and the high energy ignition coil have been adopted to improve combustion. Furthemore, variable cooling and lubulication systems have been adopted to improve fuel consumption by reducing cooling and friction losses. As a result, over 40% thermal efficiency and over 60kW/L specific power have been achieved. By combining with new TNGA 8-speed Automatic Transmission, over 16% lower fuel consumption and 12% better acceleration performance have been finally realized compared to the previous model.