Recent developments in converting the thermal energy of exhaust gasses of automobiles into electric power directly, require an extensive simulation and design of appropriate thermoelectric generation system. This work aims to create a physical model of engine exhaust system using Simscape language to simulate waste heat recovery from the exhaust gasses using (Na, K) co-doped polycrystalline tin selenide (SnSe) thermoelectric material. This particular material exhibits a high Seebeck coefficient and extremely low lattice thermal conductivity in power generation because of phonons scattering by the rattlers (Na, K atoms) and Nano-structuring. In the MATLAB/Simulink environment, a transient simulation is done for the recovery of waste heat from a 1.5 liters engine using these specific material-based thermoelectric modules. According to the results obtained, at the temperature gradient of 285 K across its sides, electrical power of 10.4 watts with a conversion efficiency of almost 5 percent is produced from one module. The total system output power was 477 watts at the exhaust gas inlet temperature of 900 K to the octagonal heat exchanger on which the modules are mounted.