In the era of BEVs, Toyota, Mazda, and Subaru collaborate to develop new combustion engines

Toyota, in collaboration with Mazda and Subaru, announced the development of a new line of compact engines. These engines will be capable of running on various carbon-neutral (CN) fuels and integrate with hybrid and electric systems.

Toyota's new engines will be smaller and more compact than current models. These engines are intended to fit into streamlined battery electric vehicle (BEV) body styles, promoting better aerodynamics and efficiency.

Toyota Chief Technology Officer Hiroki Nakajima highlighted the potential for these engines to facilitate futuristic designs, featuring low hoods and spacious interiors.

"These engines will completely differ from today's engines," Nakajima said as quoted by Automotive News, previewing the technology ahead of the official announcement. Although no concrete timeline was provided, prototypes were showcased at a press conference with Mazda and Subaru.

What engines are in the pipeline?

1.5-litre naturally aspirated engine

Designed to be an eco-friendly option, delivering significant fuel efficiency improvements over current 1.5-litre engines. It is about 10 percent smaller in volume and 10 percent lower in height than its predecessors.

1.5-litre turbocharged engine

A compact, performance-oriented powerplant that matches the power output of traditional 2.5-litre naturally aspirated engines. It is 20 percent smaller in volume and 15 percent lower in height compared to current turbocharged counterparts.

2.0-litre turbocharged engine

This engine aims to deliver higher power than today’s 2.4-litre turbo units - used in various Lexus models and Toyota Alphard/Vellfire - while offering better fuel economy. It is designed to be 10 percent smaller in volume and height, with significant advancements in thermal efficiency.

Toyota CEO Koji Sato stressed the importance of a multi-pathway approach to carbon neutrality, which includes not just EVs but also advanced internal combustion engines (ICEs) compatible with CN fuels.

"Engines represent a necessary multi-pathway technology," Sato said, rejecting the notion that the company is lagging in the shift to full electrics.

Mazda, known for its rotary engine, is also advancing its technology to run on CN fuels. CEO Masahiro Moro has initiated a dedicated team to develop a rotary engine capable of burning renewable biofuels or hydrogen, which will be used in hybrid setups.

Mazda's Chief Technology Officer Ichiro Hirose revealed that the company is working on two small-size rotary engines, aiming to maintain the brand's innovative edge.

Subaru will continue to evolve its horizontally opposed boxer engine to integrate with hybrid systems. CEO Atsushi Osaki plans to introduce a next-gen hybrid system in models like the Crosstrek and Forester, as part of a broader strategy to launch eight BEV models by the end of 2028.

"Our shared recognition is that the enemy is carbon," Hirose emphasized, acknowledging the gradual transition to BEVs and the interim need for ICEs that contribute to carbon neutrality.

"The battery and engine combinations could be numerous," Nakajima noted, highlighting the potential for these new engines to enhance hybrid systems and meet stringent future emissions standards.