First look: Subaru enters hybrid race

SUBARU parent company Fuji Heavy Industries will be among a bevy of Japanese manufacturers demonstrating its alternative power technologies at this month’s Tokyo motor show.

In addition to the electric version of the R1 minicar revealed last month, Subaru will unveil its first petrol-electric hybrid crossover vehicle.

The so-called B5-TPH employs a new hybrid power system using turbo parallel hybrid (TPH) technology. According to Subaru, the integration of TPH with its symmetrical AWD system has been developed with mass production in mind.

Central to the B5-TPH is the company’s symmetrical all-wheel drivetrain, but motivating it is both an electric motor and a turbocharged 2.0-litre boxer petrol engine.

The combination is claimed to reduce both fuel consumption and exhaust emissions, while offering "superb, all-range performance" via a motor-assist feature to boost engine torque at low revs.

In simple terms, TPH comprises a thin motor generator mounted directly on to the crankshaft, between the turbocharged boxer engine and the torque converter within its automatic transmission.

Said to solve the major problem with turbocharged engines – turbo lag – the motor-assist feature increases performance at low engine speeds.

However, the adoption of the Miller cycle principle (like that employed by some Mazda models in the past), in addition to Subaru’s Active Valve Control System (AVCS), is also claimed to contribute to improvements in fuel economy.

Preliminary B5-TPH specifications include a manganese lithium-ion battery pack, like the one that powers Subaru’s R1e mini-car, to power the motor generator.

Subaru says the system is lighter, more compact, longer lasting and provides better charge/discharge electric power density than nickel-metal hydride batteries that power many hybrid vehicles.

It is also designed as an all-in-one unit with its control module, allegedly making its easy and safe to mount on to the back of the vehicle.

The result is what Subaru describes as the next generation of petrol turbo engines with all-range performance and greater environmental benefits.

Performance statistics for the engine include maximum power of 191kW at 6000rpm and maximum torque of 343Nm at just 2400rpm, while the electric motor’s outputs are 10kW and 150Nm.

The four-seater B5-TPH measures a conventional 3670mm long, 1820mm wide and 1500mm high, but tips the scales at a kerb weight of 1380kg.

Large 19-inch wheels and 245/45-section tyres, plus 200mm of ground clearance, also aim to give the B5-TPH on- and off-road ability, while its three-door "coupe" styling blend cues from wagons, 4WDs and sports coupes.