Subaru Reveals its Next-Generation Boxer Hybrid Powertrain

To combat carbon emissions head-on, EVs may be the direction that passenger cars eventually take. However, it is clear from the steady but slow consumer acceptance of electric vehicles that internal combustion engines will still be with us for a while. That has led manufacturers, including Subaru, to develop lower carbon-emitting powertrains primarily through the use of hybrids. Ewing Subaru of Plano reports on Subaru’s latest hybrid plans. 

The somewhat loose affiliation of Toyota, Subaru, and Mazda held a joint conference to explain how they plan to pursue decarbonization short of going all-in on EVs. Toyota showed three new, smaller, and more efficient engines they are working on. Mazda, which hasn’t had a US-market rotary engine product for a dozen years, is pursuing single- and two-rotor engines to use as generators. Subaru showed its latest plan to combine its boxer engine with hybrid technology.

The New Boxer Hybrid

Subaru showed its hybrid boxer drivetrain in a camouflaged Crosstrek. The new system will lean more on a series hybrid arrangement in which the engine serves as a generator for electric motors. One advantage of this arrangement is that the engine can stay at its most efficient rpm level more often. However, Subaru says there will be a direct connection between the engine and the rest of the drivetrain when it is at its most appropriate, presumably at steady highway cruising. 

Another key difference from the previous Subaru hybrid drivetrains is in the packaging of the hybrid components. In previous Subaru hybrid systems, the power control unit was mounted in the rear, and the fuel tank had to be reduced in size to accommodate it. Subaru states that in the new system, the engine, hybrid system, transmission, transfer case, and power control unit are all housed within the engine bay, which leaves the fuel tank size as is. When combined with the engine’s greater efficiency, Subaru predicts a much longer range for its upcoming hybrid models. 

Why a Boxer, Anyway?

The engine shows Subaru’s continued commitment to the boxer engine design, which it lauds for its low center of gravity and lower vibration. Unlike inline and V engines, which position all of the engine above the crankshaft, a Boxer engine’s heads are so low as to have the same vertical center as the crankshaft, giving the car a lower center of gravity.

Production of the new boxer hybrid is expected to start this fall, which likely means Ewing Subaru of Plano can expect hybrid versions of some of Subru’s models near the beginning of 2025.