Simulation and modeling of harvestable energy from hybrid vehicle waste heat.

摘要

This book presents the simulation, modeling and estimation of the energy wasted in the form of heat from the engine via coolant flowing through the radiator and the exhaust pipe in hybrid vehicles. A mathematical model for estimating the heat energy (in the form of temperature) of the exhaust gas is also explained. The effective method of converting these wasted forms of heat energy into electrical energy which can be used for next generation hybrid electric vehicles is also mentioned here.;We have developed two models, written in Matlab, to estimate energy in real-time from the coolant and exhaust. Heat power in kW is estimated as a function of mass flow rate, specific heat capacity, and temperature. Instantaneous heat power integrated over a drive cycle resulted in the estimated energy in kWh. We have obtained mass-flow rates and the coolant temperature from the recordings of the vehicle's on-board diagnostic data (OBD). We measured exhaust-gas temperature using wired and wireless technology. In wired technology we used Max6675 thermocouple shield (Arduino as micro controller) parallel with the OBD data recording. For measuring data wirelessly we used an infrared-temperature sensor and an Arduino-Uno microcontroller with Xbee-wireless-data-interface. The dynamic specific heat capacities of the exhaust gas and the coolant are estimated as the higher order polynomial functions of corresponding temperatures. We have found that the harvestable energy per hour of driving from the coolant is about 8.44 kWh in a city drive-cycle; and it is about 16.77 kWh of energy in a highway drive cycle. It is expected that about equal amount energy can be extracted from the exhaust gas.;The heat energy generated from the coolant flowing through the radiator of the vehicle is estimated using real-time data obtained from a Nissan Maxima GLE 2001. The data are collected in a city as well as a highway drive cycle. We use On-Board Diagnostics data logger CarChip Pro 8226 which is manufactured by Davis Instruments with CarChip Pro software to read the captured data, which is then transferred to Excel and saved.;For simulation purpose, we used Matlab 2014a. Mathematical modeling of the IC Engine heat generation is done here. This model computes the amount of heat energy (kWh) per hour of driving by importing saved data in Excel from the CarChip Pro for different drive cycle.;Furthermore, this renewable energy can be converted into electric energy using stacks of thermo-electric generators (TEGs) and stored in a battery pack in order to improve efficiency in next hybrid electric vehicles.