Toyota Motor has developed new engines, transmissions and hybrid systems based on Toyota New Global Architecture (TNGA) to reduce fuel consumption and CO2 emissions.
Toyota intends to deploy these new powertrain units in a rapidly broadening range of vehicle models, starting in 2017.
Using TNGA, Toyota has been changing the automobile from its very structure, lowering hood heights, lowering the center of gravity and implementing other innovations to improve driving performance.
To enhance fundamental vehicle performance in terms of running, turning and stopping, it initiated a comprehensive review centered on vehicle platforms and is now, since the release of the fourth-generation Prius in 2015, expanding the use of new platforms throughout its product lineup. At the same time, it has been developing new powertrain units, which form the core of an automobile, that significantly improve both driving and environmental performance.
Toyota's newly developed powertrain units are light and compact and have a low-center of gravity. In-depth reconsideration of fundamental vehicle performance has resulted in engines with high-speed combustion and in highly efficient multi-geared transmissions.
Furthermore, to standardize the basic structure of these new units, modular design (unified design) was used, building a foundation for the future making of "well-built cars."
While it was a given that the new powertrain units would be designed to have a high level of environmental performance, development focused on achieving driving performance that would "change how Toyota cars drive", under the theme "Direct & Smooth."
For Toyota, the starting point of making cars is "fun to drive" the feeling of joy that comes when behind the wheel. Toyota aims to make cars with driving performance that responds to the will of the driver and are, at the same time, highly fuel efficient, among having other environment-friendly attributes.
The new powertrain units announced today, in themselves, provide approximately 10 percent better power performance and approximately 20% better fuel economy. Combining the new powertrain units with the overall evolution of the vehicle body, including aerodynamics, weight reduction and others, can open the way to even greater power performance and fuel economy.
New 2.5-liter Direct-injection, Inline 4-cylinder Gasoline Engine
Toyota has named its new line of internal-combustion power plants "Dynamic Force Engines". To bring out the new engines' potential to the fullest, their basic structure was completely rethought using TNGA, and their overall structure and configuration were wholly innovated to achieve high-level driving and environmental performance. Work will continue to make the new engines even more advanced.
The new engines employ high-speed combustion technology and a variable control system. They also achieve greater thermal efficiency, resulting in high output, due to a reduction in energy losses associated with, among others, exhaust and cooling systems and the movement of mechanical parts.
Their lineup includes a 2.5-liter engine that has one of the world's best thermal efficiencies 40% when used in gasoline-powered vehicles and 41% when used in hybrid vehicles (HVs). This new, thoroughly reconsidered and greatly evolved engine features numerous new technologies, such as technologies for minute control that make it highly responsive and allow it to generate ample torque at all speeds.
New 8-speed and 10-speed Automatic Transmissions (Direct Shift-8AT & Direct Shift-10AT)
Toyota has developed two new automatic transmissions?the 8-speed Direct Shift-8AT and the 10-speed Direct shift-10AT. For both, various measures were taken to minimize energy loss and heighten transmission efficiency.
Gear tooth surfaces were processed using a new technique for a lower coefficient of friction when the gears engage, and the configuration of the friction material used inside the clutch was optimized to reduce clutch torque loss by approximately 50% during rotation (compared to a conventional 6-speed transmission).
These and other efforts resulted in achieving one of the world's best transmission efficiencies. The new automatic transmissions are more compact and lighter than comparative conventional transmissions, lowering a vehicle's fuel requirements. And their lower center of gravity results in both improved straight-driving stability and better cornering stability.
Furthermore, widened gears and a newly developed high-performance compact torque convertor combine for a broader gear lockup range. The resulting quick and smooth response to accelerator pedal operation creates an "as desired" direct driving feel.
In the case of the Direct Shift-10AT, even though the number of gears has been increased to 10 (compared to eight gears in the case of the Direct Shift-8AT), the use of close-ratio gears optimizes the range of use of each gear, particularly in the low-to-mid speed range.
The resulting smooth gear changes, which are among the world's quickest, create a rhythmical and comfortable sensation that is suitable for a premium rear-wheel-drive vehicle.
Through such measures, fundamental vehicle performance in practical driving situations ranging from driving around town to driving on the highway has been improved to a degree that drivers can distinctly experience.
Smooth response to accelerator pedal operation enables "as desired" vehicle departure and, in overtaking maneuvers, it allows lag-free and rhythmical acceleration that meets driver expectations, even in cases of sudden and heavy accelerator pedal use.
Advancement of Toyota Hybrid System II (THS-II)
Applying size-reducing, weight-reducing and loss-reducing technologies used in the fourth-generation Prius, Toyota has enhanced its hybrid system for 2.5-liter engines and developed the new, high-performance Multistage THS II for rear-wheel-drive vehicles.
THS II for 2.5-liter engines excels in both power and fuel-economy performance due to the synergistic effect of size-reducing, weight-reducing and loss-reducing technologies coupled with the high thermal efficiency and output of a new TNGA-based engine.
Multistage THS II gives hybrid vehicles an all-new driving image with its start-from-stop acceleration performance and abundant direct feel. In addition to improving system efficiency at high speeds, intermittent use of the engine at high speeds has also been made possible, further improving high-speed fuel economy.
The system for plugin hybrid vehicles (PHVs) has also been enhanced. A new dual-mode drive system allows the electric motor, which was hitherto used only as a generator, to provide direct driving power, resulting in powerful driving, even when in EV mode. Further enhancing the system for PHVs is a large-capacity lithium-ion battery that largely increases the EV-mode cruising range to 60 kilometers or more.
Roll-out of New Powertrain Units
Through TNGA-based car-making, efficiencies have been achieved in the development of the base technologies of the new powertrain units, along with improvements in quality, making possible the concerted release of affordable, high-quality products. This will lead to Toyota being able to quickly provide its customers with ever-better cars and to further promote widespread use of environment-friendly, fuel-efficient vehicles.
Within the five years to the end of 2021, Toyota plans to introduce 17 versions of nine engines, including the 2.5-liter engine announced today, 10 versions of four transmissions, including multi-geared automatic transmissions and a new kind of continuously variable transmission, and 10 versions of six hybrid systems.
In this way, through TNGA-based modular development, Toyota will roll out numerous types of new powertrain units within a short timeframe, successively introducing them in various vehicle models, starting with the launch of a new-model vehicle in 2017.
By the end of 2021, Toyota aims to have the new powertrain units feature in 60 percent or more of Toyota-brand and Lexus-brand vehicles sold annually in Japan, the United States, Europe and China.
Toyota forecasts that Toyota and Lexus vehicles sold that year in those markets will account for a CO2 reduction in those markets of 15% or more, counting the fuel-efficiency-improvement contributions made by the new powertrain units alone.
