Few turbos in high-tech Toyota future

Production Toyota fuel-cell sedan, closely based on this FCV-R concept, is scheduled to premiere at Tokyo motor show in November 2013.

Production Toyota fuel-cell sedan, closely based on this FCV-R concept, is scheduled to premiere at Tokyo motor show in November 2013.

Published Oct 15, 2013

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If Toyota drivetrain R&D head Koei Saga is to be believed, the Empire is about to strike back.

The Empire, in this case, being the world's biggest carmaker, and the target, a widely-held perception that Toyota, after leading the world with the introduction of the Prius hybrid in 1997, is now trailing in the race to develop alternative powertrains.

Saga told Automotive News in a recent interview that Toyota was preparing a broadside of turbocharged engines, bigger Atkinson-cycle engines, constantly variable and fixed-gear auto transmissions, along with new hybrid and fuel-cell technologies.

Nevertheless, Saga seemed to be thinking outside the box, arguing against the two current mainstream paths - battery-powered pure electric cars such as the Nissan Leaf and Tesla Model S, which he described as 'targeting rich users for whom this is their third or fourth car', and down-sized, forced-induction engines, such as the Fiat Twin-air and Ford's one-litre EcoBoost triple.

EXTRACTING EVERY LAST MILLIWATT

He was quoted as saying he would rather use an 'up-sized' Atkinson-cycle engine, in which the inlet valve is left open a little longer than in a conventional four-stroke cycle, allowing some of the inlet gases to flow back into the intake manifold.

Properly timed - particularly when allied to direct fuel-injection - the effect is to extract every last milliwatt of energy from the fuel in a very clean combustion process, albeit at a significant cost in top-end power. Most hybrids today have combustion engines using the Atkinson cycle.

Saga was also quoted as saying that drivers who bought turbocharged vehicles did so for extra power rather than increased efficiency - which may explain why Toyota has been reluctant to go the easy route of bolting a Subaru turbo to the flat-four engine of its agile but underpowered 86 sports coupé.

70-YEAR-OLD TECHNOLOGY

Then he turned the clock right back to the 1940s by saying Toyota was looking at water injection, which cools the combustion chamber, practically eliminates detonation and provides a limited amount of extra power by turning into high-pressure steam during combustion.

Water injection was a popular way of increasing take-off power in piston-engined military aircraft, which disappeared (except for racing applications) with the advent of jet engines.

However, he conceded that programming microprocessors to control the wildly varying fuel-air mixtures used in water-injected engines for use in a street-car environment would need 'giant computers' - but that doesn't mean he's not working on it.

Saga also downplayed the use of lithium-ion batteries in hybrids (Toyota still uses nickel-metal hydride batteries) telling Automotive News that to make a lithium-ion battery as durable as a NiMH battery would negate its size and weight advantages - whiles still pointing out that the energy density of the lithium-ion battery made it 'a must' for a plug-in hybrid.

PRODUCTION FUEL-CELL SEDAN SLATED FOR 2015

At the same media event, Automotive News quoted alternative vehicles, powertrains and chassis development managing officer Satoshi Ogiso as saying that the cost of a hydrogen fuel cell - currently about $100 000 (R990 000) - would be halved to about $51 000 (R505 000) by the time Toyota's first fuel-cell car went into production early in 2015, and halved again by 2020, making fuel-cell cars competitive with hybrids and cheaper than battery cars.

It's no secret that the fuel-cells in the 100 or so Hydrogen Highlanders that Toyota built in 2007 cost nearly $1 million (R9.9 million) each but Ogiso was quoted as saying that global sales of 5000 - 10 000 a year would bring that down to five percent of that in 10 years.

Expect to see the Toyota fuel-cell sedan unveiled at the Tokyo motor show in November 2013.

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