KATHMANDU: Subaru is developing a more fuel-efficient version of its signature boxer engine as it prepares to expand its hybrid lineup, particularly in the US market.
The Japanese automaker unveiled its next-generation boxer engine technology in October. It plans to use the new engine in both petrol and hybrid vehicles, rather than abandon the technology that has long defined its cars.
Subaru’s boxer engines feature horizontally opposed pistons that move in opposite directions. The design provides a lower center of gravity, improving vehicle stability and handling. However, fuel efficiency has remained a weakness compared with conventional engines.
For example, the 1.8-liter turbocharged Subaru Levorg delivers around 13.8 km/l, while the 1.5-liter turbocharged Honda Civic achieves approximately 15.7 km/l.
To address this gap, Subaru has redesigned the engine’s intake system to improve airflow and refined its turbocharger technology to improve combustion. The company expects the new design to achieve thermal efficiency of around 45%, up from approximately 40% in its current engines.
Subaru plans to use the engine to directly drive the wheels in both petrol and hybrid models. Further improvements towards 50% thermal efficiency could require engines dedicated to generating electricity in hybrid systems.
The development comes as hybrid demand increases in the US, Subaru’s key market, while interest in electric vehicles has cooled. The company is also facing pressure to revive global sales, which have remained around 900,000 units annually in recent years after reaching a record 1.06 million in fiscal 2017.
Meanwhile, other automakers are also pursuing more efficient engines. Nissan is targeting 50% thermal efficiency for its e-Power hybrid generator engine. BYD has also developed a 2.0-liter turbocharged boxer engine for a plug-in hybrid under its premium Yangwang brand, writes NIKKEI Asia.
