Search Results

This paper describes predictive models and validation experiments used to quantify the in-chamber heat transfer of LiquidPiston’s rotary 70cc SI “XMv3” engine. The XMv3 engine is air cooled, with separate cooling flow paths for the stationary parts and the rotor. The heat transfer rate to the stationary parts was measured by thermal energy balance of that circuit’s cooling air. However, because the rotor’s cooling air mixes internally with the engine’s exhaust gas, a similar procedure was not practical for the rotor circuit. Instead, a CONVERGE CFD model was developed, and used together with GT-POWER to derive boundary conditions to estimate a ratio between rotor and stationary parts heat transfer, thus allowing estimation of rotor and total heat losses. For both cases studied (5000 and 9000 rpm under full load), the rotor’s heat loss was found to be ∼60% that of the stationary parts, and overall heat losses were less than 35% of supplied fuel energy.

Currently, a great deal of the automotive industry's R&D effort is focused on improving overall vehicle environmental and energy efficiency [1]. For instance, one of the things that Electric Vehicles (EVs) and Hybrid cars (HEV) have in common is the recovery of waste energy, namely during braking. But, when an I.C. engine is operating (e. g. as a range extender in an EV), a large amount of energy is also wasted within the exhaust gases and with engine cooling, energy that could otherwise be recovered by different methods. This paper reports on the recovery of waste thermal energy using thermoelectric generators (TEG) for application in hybrid, extended range electric vehicles and more generally in any vehicle that could benefit from the generation of a small amount of electric current that would reduce the alternator operation time.