Development and characterization of thermoelectric generators for thermal energy recovery from reciprocating internal combustion engines

Since the beginnings of the automotive driven with internal combustion engines all the cycles used in the alternative motors share a thermal characteristic, a large amount of heat released by the fuel is lost in the form of hot gases that exits from the exhaust system. This research has intensified in recent years due to the consequences of climate change, and above all, the Administration pressure on automotive manufacturers regarding the reduction of pollutant emissions, especially CO2. The system proposed in this thesis uses the advantages that thermoelectricity can provide, a thermoelectric generator can meet the requirements mentioned above. The scope of application of thermoelectric materials is very large, from temperature sensors, through portable coolers, to solar power generators. In general, these applications can be classified according to the direction of the energy conversion. While the Peltier effect is used in solid-state refrigeration, the Seebeck effect is responsible for converting the temperature differences into electrical voltage in energy recovery systems. The Seebeck effect is what our want to produce in a vehicle when you want to recover heat energy, because thanks to the thermoelectric materials the electricity produced can be injected into the vehicle's electric system by reducing the load of the alternator and therefore the overall consumption of the thermal engine. This doctoral thesis addresses aspects that until now had been little explored by the researchers: (i) the effects on the behavior of the motor when a new system is introduced in the exhaust line, (ii) the use of software sufficiently powerful to simulate the integration of the thermoelectric generator into a complete vehicle and (iii) the experimental quantification of the consumption savings when thermoelectric generators are incorporatedL’aprofitament energètic de la calor residual dels gasos d’escapament és una fita perseguida per molts fabricants i investigadors en el camp de l’automoció. Aquesta recerca s’ha intensificat en els últims anys motivada per les conseqüències del canvi climàtic, i sobretot, per la pressió de les administracions sobre els fabricants d’automoció pel que fa a la disminució de les emissions contaminants, especialment del CO2. El sistema proposat en aquesta tesi utilitza els avantatges que pot proporcionar la termoelectricitat, considerant que un generador termoelèctric pot satisfer els requisits esmentats anteriorment. Aquesta tesi doctoral aborda aspectes que fins ara havien estat molt poc explorats pels investigadors : (i) els efectes sobre el comportament del motor quan s’introdueix un sistema nou a la línia d’escapament, (ii) la utilització de software suficientment potent per simular la integració del generador termoelèctric en un vehicle complet, i (iii) la quantificació experimental de l’estalvi de consum quan s’incorporen generadors termoelèctric