Subaru is currently working on its next-generation of boxer engines and there's a very real possibility that these will be the Japanese automaker's last series of internal combustion engines. Why? Because Subaru is aiming to be an entirely electric brand in a decade. At present, only the Subaru Crosstrek offers a hybrid version but other models are expected to follow. Subaru's current boxer engine family is coming towards the end of its lifecycle, but replacements are coming sooner than you think.

According to new details from Japanese publication CarSensor, Subaru is planning to launch three new turbocharged, direct-injected four-cylinder boxer engines early next year. And yes, one of them is expected to power both the next-gen Subaru WRX STI and BRZ.

The first of these new engines, a 1.5-liter with direct-injection, is expected to replace the naturally aspirated 2.0-liter found in the base Crosstrek and Impreza. It should produce about the same amount of power as the 2.0, but efficiency will be improved. Next up is a 1.8-liter also with around 265 hp on tap that could power the next Outback, Legacy, and Ascent.

And lastly, there's a new 2.4-liter in the works. What's interesting is that it's being developed with at least two levels of performance, with the least powerful version producing around 276 hp. A high-output version could pump out as much as 400 hp. Needless to say, it will provide the next WRX STI's thunder.

The engine could be detuned slightly to around 330 hp for the BRZ (and Toyota 86). That added boost, however, is likely to come courtesy of a hybrid system. In fact, it's possible all three engines are going to be paired with hybrid tech, hence the 2.4's fairly significant output range. Mating these engines with batteries and electric motors makes absolute sense, especially if Subaru truly intends ditch combustion within ten years.

Assuming this is indeed the plan, then Subaru's long-time association with the boxer engine layout is entering its final era.