The company is promising a 20 percent improvement in fuel efficiency and claiming that the new Crosstrek Hybrid can drive more than 621 miles on a single tank of fuel.

Subscribe to TheStreet's free daily newsletter Toyota brought a pair of four-cylinder engines, Mazda showed off a revamped and reworked version of its signature Wankel rotary engine, while Subaru showed off a hybrid version of its signature flat "boxer" engine installed in a prototype version of its popular Crosstrek crossover SUV.

Subaru's vehicles are beloved by their fans for plenty of reasons, but generally speaking, fuel economy isn't one of them. As a result, there's been plenty of interest in the automaker's vague plans to roll out hybrid models using a Toyota-based system in the near future.

Now, extended details have been published ahead of December when the Crosstrek will be the first model to utilize the next-generation hybrid system. At the heart of the new hybrid system is a naturally aspirated,