Small Size Dictates Technology Development at Subaru

Special Report

Japanese Drivelines

Part 1

Torque-Vectoring, Performance Key to Honda ESC Development

Part 2

Toyota Focuses on Safety With Advanced ESC Technology

Part 3

Responsiveness Key to Mitsubishi AWD Development

Part 4

Nissan Seeks Value in Advanced ESC Systems

Part 5

Small Size Dictates Technology Development at Subaru

Part 6

Mazda ESC Strategy Depends on Ford

Japan’s six major auto makers are divided into two camps on future strategies for stability-enhancing driveline technologies: safety benefits vs. performance improvements. Part 5 of this 6-part series examines Subaru’s driveline strategy.

UTSUNOMIYA, Japan – Fuji Heavy Industries Ltd., maker of Subaru vehicles and a leader in all-wheel-drive technology since the 1980s, sees difficulties in advancing its core technology due to its relatively small size.

The auto maker has yet to include the latest stability-enhancing AWD technologies, such as torque-vectoring, in any of its long-term development planning.

A senior Subaru research official, speaking on condition of anonymity, cites three issues that will impact future decisions on all advanced technologies, including drivelines.

First, Subaru is one of the least profitable and smallest auto makers in Japan, which usually prevents it from being a leader in introducing new technologies.

Second, due to the unique layout of Subaru’s horizontally opposed boxer 4- and 6-cyl. engines, the auto maker faces special obstacles in attempting to achieve economies of scale through partnering with other auto makers on platform and powertrain development and component sharing.

Finally, the auto maker’s Japanese supplier group is relatively weak compared with larger competitors such as Toyota Motor Corp., Nissan Motor Co. Ltd. and Honda Motor Co. Ltd. Combined with its relatively small size, this hinders in-house development of proprietary technologies.

When torque-vectoring technology, which selectively applies drive torque to individual wheels on the same axle, was first introduced on the ‘91 Acura Legend, Subaru researchers initially thought it would compete with antilock brakes and electronic stability control (ESC).

Low selling prices for all Subaru models may hinder ability to develop advanced stability-control systems.

They now see the technology as complementing, not competing, with established dynamic vehicle controls.

“The combined package enhances both vehicle stability and safety,” the Subaru source says.

However, price continues to be a limiting factor. In the current business environment, torque-vectoring AWD systems are restricted to cars priced at more than ¥2.5 million ($21,083), the official says.

“Below that price, auto makers will opt for conventional electronic controls (electronic AWD differentials),” he says.

By 2010, Subaru is aiming to reduce its vehicle sticker-price threshold for electronic couplings to ¥1.5 million ($12,648).

The auto maker currently has adopted a variable front-to-rear torque distributing AWD system for the Legacy sedan and B9 Tribeca cross/utility vehicle, both of which are powered by 3.0L 6-cyl. engines. For the 2.0L and 2.5L turbocharged Legacy, Forester and Impreza, Subaru employs an older version of the system.

The Subaru executive does not expect the auto maker to introduce vehicle dynamic controls into Japan’s minivehicle segment, such as the 0.66L Pleo, R1 and R2, because the technology is too costly.

Subaru’s main objectives in introducing torque-vectoring technologies are to enhance the brand, followed by improving vehicle safety.

Looking at AWD markets, the official sees two major trends emerging in North America: A steady shift away from mechanical differential systems to electronically controlled units as consumers switch to car-based CUVs and the “hybridization” of conventional truck-based SUVs, such as the GMC Yukon.

In Europe, he predicts steady but slower growth in AWD demand by virtue of more than half of new light vehicles sold are diesel-powered.

“Diesel powerplants complement AWD,” the source says. “They produce high torque at low speed, thus have performance advantages in mountainous areas.”

Although Subaru has considered developing a Toyota-like ESC system that incorporates active steering, its most expensive model, the Legacy, bases for only ¥3 million ($25,297).

This stands in contrast to Toyota’s Lexus luxury lineup, where average sticker prices are nearly double that of most Subarus.

“Toyota has an advantage in introducing this sort of advanced technology,” the executive says.

“As a result, Subaru will focus on enhancing vehicle dynamic controls until 2008 or 2009, then try to introduce a (Toyota)-like system on the (next generation) Legacy.”

In the future, Subaru, like other Japanese auto makers, will attempt to integrate collision avoidance and other advanced safety technologies with its AWD systems.

However, several years ago Subaru equipped the Legacy with a charge coupled device camera to alert drivers of frontal obstacles.

“Virtually no one purchased the (optional) system,” the official says.