Hybrid-electric system truth test: Energy analysis of Toyota Prius IV in real urban drive conditions

Abstract

The experimental work, carried out through road tests in the city of Rome (Italy), assesses the energy performance of the Toyota Prius IV generation with Full Hybrid traction system under real conditions of use in the urban environment.The evaluation was carried out through a data collection campaign on a 37 km urban route, in both fast-flowing sections and traffic-congested areas of Rome. On this route, 60 driving tests were carried out by individual with different characteristics in terms of gender, age and hybrid technology driving experience.In particular, the analysis involved the operation as ZEV (Zero Emission Vehicle) vehicle, the hybrid system Power flows, fuel consumption and yields.The most relevant results relate to the high percentage (in time and space) of operation in ZEV mode: this mode is achieved both in “electric” operation, that is, with power output to the wheels by the electric motor only (with the ICE off), and in the inertial operation, i.e. without power output to the wheels (always with ICE off).Another important result concerns the high overall efficiency of the hybrid traction system, obtained thanks to the high average yield of the ICE, and especially through the very high deceleration energy recovery. The recovered energy provides a very significant contribution to the total energy needed by the wheels for the car movement purposes and, in particular, provides the vast majority of electricity required by the electric motor.