Toyota revs its engine development


Toyota is preparing a wave of more efficient engines, beginning with the redesigned Auris hatchback. Photo credit: HANS GREIMEL

TOKYO — Toyota Motor Corp. will introduce a sweeping powertrain portfolio starting this spring as part of a five-year overhaul to make its vehicles more fuel-efficient but sportier to drive.

The engine wave begins with a cleaner, more powerful 2.0-liter that will appear first in the redesigned Auris hatchback, which is to debut at the Geneva auto show. The Auris is the European and Japanese version of the Corolla iM sold in the U.S.

By 2023, new engines and transmissions will power 80 percent of new Toyota vehicles.

Also among the new products are more dynamic all-wheel-drive systems for trucks and hybrids and a continuously variable transmission that counters the rubber-band feel often derided by CVT critics by adding a toothed “launch gear.”

The powertrain blueprint is Toyota’s clear signal that it sees big potential for improving old-school internal combustion technology, even in the dawning age of electrification.

While Toyota expects half its nameplates to be electrified by 2030, some 90 percent of its vehicles will continue to rely on fuel-burning powerplants, said Mitsumasa Yamagata, Toyota’s chief engineer for powertrain planning, in laying out the plans.

“Even in 2030,” he said.

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Just 10 percent of Toyota’s models will dump engines altogether in favor of full electric or fuel cell powertrains. Thus, Toyota’s key focus at the moment is improving the humble gasoline powerplant.

“The evolution of engines and transmissions will also reduce carbon dioxide emissions and greatly contribute to the environment,” Yamagata said.

Big makeover

The new portfolio of engines and transmissions is accompanying an even bigger makeover for Toyota. The automaker is launching — one nameplate at a time — what it calls its TNGA modular vehicle platform around the world. TNGA, which stands for Toyota New Global Architecture, will yield cars and trucks that are lighter and simpler to build and modify. To pair with all those newly designed vehicles, Toyota plans to introduce 17 versions of nine new engines by 2021. There also will be 10 versions of four new transmissions and 10 versions of six hybrid systems.

The wave to come

Toyota’s plans for new powertrains include

  • 17 versions of 9 new engines by 2021
  • 10 versions of 4 new transmissions
  • 10 versions of 6 hybrid systems

By 2023, those powertrains will underpin 80 percent of all new vehicles sold in the U.S., Europe, Japan and China, cutting Toyota’s overall fleet emissions 15 percent from 2015 levels.

The first of the new engine technologies is the 2.0-liter Dynamic Force gasoline engine that will debut inside the third-generation Auris in Geneva.

Compared with the engine it replaces, the Dynamic Force delivers 18 percent better fuel economy and 18 percent faster acceleration when combined with a CVT. When mated to a hybrid system, the engine gets 9 percent better fuel economy and 18 percent better speed off the line.

Toyota’s engineers achieved the improvements through several tweaks. They increased fuel-air turbulence in the cylinders for a faster burn. That was done using a technology typically reserved for Formula One racing engines known as “laser cladding.” The result is a valve seat with a widened valve angle, which Toyota believes is a first for mass-production cars.

Other gains came from introducing direct fuel injection, optimizing valve-timing control and using an electric water pump to reduce mechanical friction, Yamagata said.

The new 2.0-liter engine achieves thermal efficiency rates of 40 to 41 percent, compared with 37 to 38 percent in the previous-generation engines. The first Dynamic Force engine was the 2.5-liter four-cylinder that appeared last year in the redesigned Camry sedan.

Transmission tweak

On the transmission front, Toyota has attempted to tackle a common complaint about CVTs.

Pulley-and-belt-style CVTs account for a hefty portion of Toyota’s lineup because they are typically more fuel-efficient than traditional toothed-gear automatic transmissions. But their rubbery, delayed feel during acceleration sometimes leaves drivers unenthused.

Toyota’s solution was to put a single “launch gear” into its CVT to help give the transmission immediate bite for better low-end torque. After ramping up to speed, the system switches to the belt-style function. By achieving a wider range of gear ratios, it delivers not only better feel but better efficiency. Toyota claims fuel economy improves 6 percent over today’s CVTs.

Toyota calls the innovation a direct-shift CVT.

Toyota’s engine plans also acknowledge the market’s rapid shift toward light trucks, a U.S. sales trend the Japanese automaker has been slower to capture than rivals.

On tap are two awd systems that aim to improve fuel efficiency, stability and off-road performance. The systems could be used in SUVs, crossovers or even cars.

The first, called dynamic torque vectoring awd, is geared toward gasoline vehicles and channels torque independently to the right and left wheels for better handling.

It also can disconnect drive rotation to the rear wheels in two-wheel-drive mode to boost fuel economy.

The version for hybrids, called E-Four, delivers 30 percent more torque to the rear wheels compared with Toyota’s current awd setup for hybrids.

Both versions feature a new awd integrated management system, which Toyota says better harmonizes the engine, transmission and braking.

Toyota also plans a six-speed manual transmission that is lighter, more compact and more efficient than the outgoing gearbox.

The efforts to get more fuel economy from its conventional internal combustion engines occur even as Toyota invests headlong in full electric technology. Toyota, long perceived as an EV skeptic, announced in December that it plans to introduce more than 10 EVs worldwide by the early 2020s.

But the bridge technology to those EVs will be more efficient engines, helping Toyota achieve better fuel economy in hybrids and plug-in hybrids while the industry gradually shifts to more costly EVs.


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