Kia Ray, the unexpected parallel plug-in hybrid

We know there are 2 main technical architectures for hybrids. The most common is the parallel one, which the Prius and all the other Toyota hybrids have. The name is parallel because the gas engine and the electric motor stand next to each other, and one or the other gets the car moving, or both altogether.

Being parallel not meaning being equal, this is the easiest architecture, because you can just add a small electric motor before the transmission of an existing car to make it. The Honda system, Integrated Motor Assist as it’s named, is a parallel system. In the Insight, the engine makes 88 hp, whereas the electric motor makes 14 hp. Huge difference, as I repeat, parallel doesn’t mean equal.

Most parallel hybrids are this way, with the gas engine much more powerful than its electric counterpart. Space being limited under the hood of any car, you would not expect the electric motor to be as powerful as the gas engine. It would just require too much space. And we shall not forget that the bigger the motor, the bigger the transmission that will reunite the power of both units, and the bigger the batteries.

For this and many other reasons, when you want a powerful electric motor and some range, most engineers prefer the other hybrid architecture, the serial hybrid one. This is where the car is at first an electric car, running on batteries. But instead of having to plug when the batteries are getting low on power, a small gas engine kicks in. That engine is not connected in any way to the wheels. Its sole mission is to act as a generator, to recharge the battery on the go.

The Chevrolet Volt is built this way, so I’m not the only one to think it’s a winning combination. But Kia’s engineers have thought otherwise with their Ray concept-car. Well, I’m not sure about that. My guess is that Kia’s working on a hybrid car, similar to the japanese models, I mean, not plug-in. The Ray concept highlights this forecoming model with a souped up drivetrain, turbocharged engine for power and extra batteries for range, but I really doubt its architecture would have been the choice of engineers if their first and only was to make a plug-in hybrid.