Drive systems
XC90 Twin Engine is a parallel hybrid, which means that it has two separate drive systems: an electric motor and an internal combustion engine. Depending on the driver-selected drive mode and available electric energy, the two drive systems can be used either individually or in parallel.
Two drive systems
An advanced control system combines the properties of both drive systems in order to provide optimum driving economy.
Hybrid battery 
Internal combustion engine 
High-voltage generator 1
Electric motor
Both the internal combustion engine and electric motor can generate motive force directly to the wheels. The internal combustion engine can also charge the electric motor's hybrid battery with a special high-voltage generator.