Editor's note: An incorrect photo appeared in the section about Hitachi's lithium ion battery. It has been corrected.
YOKOHAMA, Japan -- Japan’s premier automotive engineering expo is bustling again along the Yokohama waterfront.
A record 488 companies are participating at this year’s meeting of the Society of Automotive Engineers of Japan, which runs through Friday. Some 80,000 visitors are expected.
Here’s a quick peek at five cool innovations on display.
Electric Twist Beam, from ZF
The German transmission maker is developing an in-axle motor drive system for electric vehicles. Dubbed the Electric Twist Beam, it positions two electric motors at the ends of the axle, where a conventional axle joins the wheels.
The advantage is that the axle-motor assembly can be easily swapped for a traditional axle, allowing automakers to seamlessly create all-electric versions of nameplates with standard internal combustion engines.
Total power output from both electric motors is 80 kilowatts. ZF Friedrichshafen AG aims to commercialize the system by 2018.
SiC Inverter, from Denso
The top supplier in the Toyota Group is working on a new inverter for electric and hybrid vehicles that experiences one-quarter of the energy loss of today’s inverters.
The secret is using energy-efficient semiconductors made out of silicon carbide, instead of silicon, as is done now.
The initiative dovetails with efforts at Toyota Motor Corp. to develop silicon carbide semiconductors for the power control units in hybrid vehicles. Toyota reckons doing so can improve fuel economy by as much as 10 percent.
By using the same chips in its inverter, Denso Corp. can make the next generation inverter smaller and more powerful.
The inverter under development is 0.75 liter in volume, compared with 10 liters for the inverter Denso currently supplies for the Toyota Camry Hybrid. Its power density is 100 kilowatts per liter, as opposed to 20.
No word on a commercialization timeline.
Mirror Bore cylinders, from Nissan
Nissan Motor Corp. aims to tackle energy loss due to friction by polishing the insides of its engine cylinders to a shiny, mirror-like sheen. Nissan calls it Mirror Bore Coating.
Nissan makes the super slick cylinder walls by spraying liquid iron onto them and then polishing, polishing, polishing.
The process creates a coating that is just 0.2-millimeter thick, compared with the conventional 2-millimeter rough iron liners currently used. Besides being smoother, they are lighter and have better thermal conductivity.
Nissan aims to apply the technology to its engines worldwide.
Prismatic Li-Ion Batteries, from Hitachi
Hitachi Automotive Systems Ltd. has developed a new lithium ion battery for hybrids that is flat and rectangular, instead of cylindrical.
The new shape allows more compact packaging and better heat management. And while the battery chemistry is unchanged, the power output density has increased 13 percent to 3,400 watts per kilogram from 3,000. Engineers say they can eventually boost power density to 4,500 watts per kilogram.
Hitachi already makes cylindrical lithium ion batteries for the Infiniti QX60 Hybrid crossover and Buick eAssist mild hybrids.
The Japanese supplier will start selling the improved batteries in the second half of 2015. Hitachi already has customers, but executives aren’t saying who they are.
New rotary engine, from Mazda
Mazda is back with a new rotary engine, this time deployed as a range-extending generator for a hybrid vehicle.
The tiny 0.33-liter single-rotor engine is packaged with a 75-kilowatt electric motor and 20-kilowatt-hour battery and mounted on a Mazda2 subcompact hatchback.
The exhibit drew lots of attention from fans eager to see Mazda revive the engine it made famous in such cars as the RX-7.
But the Mazda RE Range Extender Mazda2 is just a test car to explore new applications for the power plant.
The Mazda2 range extender concept is similar to that of the Chevrolet Volt. The battery and electric motor power the wheels as in an electric vehicle. But when the battery needs a recharge, the engine kicks on to generate more electricity.