Hybrid Power Pack: Hybrid Powertrain for City Cars

This paper presents a novel concept, the Hybrid Power Pack (HPP), which consists of a hybridization kit for transforming small city cars, powered by an original diesel engine, into a parallel hybrid vehicle. The study was jointly conducted by the University of Rome “Sapienza” and the Enea Casaccia research center. The idea is to design a hybrid powertrain that can be installed in a typical microcar, which means that all systems and components will be influenced by the limited space available in the motor compartment of the vehicle. In this paper the details of the mechanical and electrical realization of the powertrain will be discussed and the simulation of a small city car equipped with HPP will be presented and the results discussed and analyzed. The hybrid system also includes the battery pack which is composed of twenty-four Li-ion cells made by EIG, connected in series. The storage system is controlled as regards the voltage and temperature by a Battery Management System (BMS). All the above components are connected and managed by a control unit. The HPP presented in this paper obtains a reduction in fuel consumption higher than 20%. The solution presented with the HPP with its management strategy and the addition of the “plug-in function” makes the hybrid vehicle suitable in terms of performance and consumption in every driving conditions. The ideal strategy behind the “plug-in function” could represent a guideline for further achievements and experimentations, because it offers a simple hardware layout and a real reduction in fuel consumption.