Toyota's engine overhaul
Hybrid leader trails in turbos, fuel injection
By Hans Greimel
"By 2015, through improvement in the engine and powertrain alone, we aim to achieve a fuel-efficiency improvement of 10 percent to 20 percent on the models adopting the improvements," Takeshi Uchiyamada, Toyota's outgoing product development chief, said.
Insiders say President Akio Toyoda, who wanted to make his company's cars zippier to drive without sacrificing fuel economy, urged his staff to embrace nonhybrid technologies.
Moreover, Toyota plans to combine direct injection with its hybrid system to deliver a new generation of hybrids that are all the more miserly with fuel.
Key elements of Toyota's plan
• A 2.5-liter direct-injection, Atkinson cycle engine, to be deployed first in hybrids in 2013.
• A 2.0-liter downsized turbo-charged engine in 2014.
• A shift to CVTs in small- to mid-sized vehicles.
• More six- and eight-speed automatic transmissions for larger cars.
Starting next year, Toyota will answer by piggybacking its D-4S direct-injection technology onto its AR family of four-cylinder gasoline engines. Toyota's AR engines are used in such models as the Toyota Camry, RAV4, Highlander and Venza and the Lexus RX. The injectors are supplied by Denso Corp.
A direct-injection, 2.5-liter AR four-banger initially will go into the hybrid version of the Toyota Crown, a Japan-market sedan. Future deployments could go in the Camry or other AR cars.
In 2014, Toyota will introduce a downsized 2.0-liter, four-cylinder turbocharged AR engine based on the 2.5-liter powerplant. Toyota declined to identify the model or the turbocharger supplier.
Pairing direct injection with Toyota's hybrid technology can boost the system's overall fuel efficiency by 10 percent, said Satoshi Ogiso, chief engineer for the Prius family of hybrids.
Toyota will use a newly refined version of the Denso-made D-4S injector. It was first used this year in the Lexus GS and the Scion FR-S sporty car manufactured by Subaru-builder Fuji Heavy Industries Ltd.
It improves mileage about 1 percent over Toyota's earlier D-4S injector, which debuted in 2006. It gets better results by using a slit-shaped, instead of a multihole, injector opening. That creates a richer fuel mixture inside the cylinder.