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Toyota's engine overhaul

Admin01.10.2012г 

For years, Toyota Motor Corp. has put hybrids at the center of its powertrain technology strategy, all but oblivious to the rapid fuel economy advancements rivals have made in the humble gasoline engine.

Meanwhile, Ford, Honda, Mazda, Hyundai, Volkswagen and others have turned to gasoline direct fuel injection and turbochargers. For them, those technologies were a quick, cost-effective route to better mpg. Turbochargers, for example, allowed them to maintain power output while making engines smaller, for a significant weight savings and higher fuel economy.

Now, in a major overhaul of its lineup, Toyota is playing catchup. It will introduce a new direct-injection engine next year and follow with a downsized turbocharged powerplant -- its first -- in 2014. It is also committing to continuously variable transmissions across its range of small- to medium-sized cars.

Toyota is hardly forsaking gasoline-electric hybrids. It plans to introduce 14 new hybrids by 2015. But hybrids, led by the Prius, still represent only 10 percent of Toyota's global sales.

Toyota's latest environmental technology game plan, unveiled in Tokyo, shows it will start doubling down on the standard powertrains that are the backbone of its offerings. And Toyota expects big gains in fuel economy for its nonhybrid vehicles.

"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.

The rollout won't happen overnight. Engineers are still debating how widely technologies such as direct injection and turbocharging should be applied.

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.

Today, the company doesn't offer any turbocharged vehicles. It experimented briefly with turbos in the 1980s but chiefly as a way to boost output from already powerful engines -- not as a way of getting more oomph from smaller, more efficient ones. And direct injection is limited to a handful of large-displacement V-6 and V-8 luxury sedans, such as the Lexus LS.

Compare that with rivals' lineups. Ford Motor Co., for instance, makes extensive use of turbocharging, from engines with displacements as small as 1.0 liter to engines in its big pickups. Honda Motor Co. and Mazda Motor Corp. are overhauling their engine lineups to make fuel injection their base technology.
From 2013

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.

"This is the beginning of gasoline direct injection for the four-cylinder engines," said Takashi Shimura, general manager for engine development. "Smaller engines will be following this engine. As a trend, this is right. It will be standard."

Shimura said direct injection will start in bigger engines and trickle down to smaller ones. He didn't give a timeline.

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.

But it is still unclear whether the next-generation Prius, due around 2014, will get direct injection.
Cost issues

The problem is balancing the added cost of fuel injection against the goal of making the Prius as affordable as possible. Cost sensitivity is compounded because the Prius, with its extra battery, electric motor and inverter, is already pricey to build. Direct injection would add an extra ¥10,000 ($128) to the car's cost, engineers say.

"It may be possible, but it still has to undergo a lot of discussion," Ogiso said. "That's because the Prius engine already has very good fuel efficiency without direct injection."

Yoshihiko Matsuda, field general manager in charge of engine engineering, says direct injection could be applied in hybrids with engine displacements of 2.0, 2.5 or 3.0 liters. But he said using it in a 1.6-liter hybrid would be "borderline" -- delivering only incremental benefit for the added cost.

The current Prius has a 1.8-liter engine.

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.

Toyota's embrace of more widely used technologies comes as it concedes it misread market demand for other alternative drivetrain technologies, including electric vehicles and plug-in hybrids.

In announcing plans for Toyota's own EV, Uchiyamada said the company would sell only about 100 of the cars in the United States and Japan on a limited basis, starting this December.

Two years ago, he predicted Toyota would be selling thousands of the EV, which is based on the Scion iQ minicar and called the eQ.

"But two years later, we found other conditions prevailing in the market, and we'll undertake a limited introduction," he said, in a tacit nod to the tepid sales of other makers' electric cars.

Uchiyamada added that sales of the Prius Plug-in, which began in Japan in January, were lower than expected. He said that car needs better marketing.

But Toyota is bullish on hybrids.

Toyota plans to launch 21 new or redesigned hybrid vehicles by the end of 2015. Toyota didn't name the models. But 14 will be either all-new nameplates or hybrid versions of vehicles that don't currently come with an electric-gasoline option.