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 percent when used in gasoline-powered vehicles and 41 percent 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 percent 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.
