The Toyota Prius represents the first worldwide commercially produced hybrid vehicle. Recently the Toyota produced the new Prius version, significantly improving the performances of its predecessor and introducing the concept of "Hybrid Synergy Drive" (THS II), an evolution of the past "Toyota Hybrid System" (THS).
Three rotating components form the vehicle transmission. The internal combustion engine is a 4-cylinders 4-strokes engine using the Atkinson thermodynamic cycle; the electric motor and the generator are both three-phases permanent magnet synchronous AC motors. These three rotating components are connected each other with a kind of CVT transmission characterized by a planetary gear box, referred to as Power Split Device. An electronic control system regulates the rpm of the three components based on many variables such as the external loads, the fuel consumption, the emissions, the state of charge of batteries and the user power demand, which directly relates to torque.
This paper reports on the results of a test campaigns carried out on both THS and THS II to assess vibration and acoustic responses under real on-road conditions. The analysis deals with multiple rpm order tracking and shows how different rotating components affect the interior vibro-acoustic comfort as well as the car drivability and pleasantness.
