Optimization and application of Stirling engine for waste heat recovery from a heavy-duty truck engine

In this thesis, the use of the Stirling engine for recovery of waste heat from a heavy-duty truck diesel engine is studied in detail: First, the maximum theoretical non-dimensional shaft work for three types of Stirling engines is calculated, and out from the three types are compared by optimizing selected parameters in the shaft work equation using a first-order analysis. The results show that the Beta-type Stirling engine is more effective than the Alpha and Gamma types with higher power density. Results are then used for a preliminary design of the waste heat recovery (WHR) system from the exhaust gases of a commercial truck. Calculations carried out with exhaust gas temperatures measured on-road tests show that the WHR system can provide 1\% of internal combustion engine (ICE) power output, corresponding to 3 kW, offering about 0.4\% reduction in fuel consumption. Second, a dynamic analysis is performed on the Beta-type engine using a second-order analysis, considering size constraints. Four Beta-type Stirling engines that use the exhaust gas recirculation (EGR) cooler or the tailpipe as a heat source are simulated. The dynamic analysis shows that the Stirling engine WHR system does not generate a reasonable power output because of the low heat transfer rate from the truck's exhaust gas. Therefore, it does not appear feasible for use in commercial vehicle applications.