Mass-produced, off-the-shelf automotive air compressors cannot be directly used for boosting a fuel cell vehicle (FCV) application in the same way that they are used in internal combustion engines, since the requirements are different. These include a high pressure ratio, a low mass flow rate, a high efficiency requirement, and a compact size. From the established fuel cell types, the most promising for application in passenger cars or light commercial vehicle applications is the proton exchange membrane fuel cell (PEMFC), operating at around 80 °C. In this case, an electric-assisted turbocharger (E-turbocharger) and electric supercharger (single or two-stage) are more suitable than screw and scroll compressors. In order to determine which type of these boosting options is the most suitable for FCV application and assess their individual merits, a co-simulation of FCV powertrains between GT-SUITE and MATLAB/SIMULINK is realised to compare vehicle performance on the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) driving cycle. The results showed that the vehicle equipped with an E-turbocharger had higher performance than the vehicle equipped with a two-stage compressor in the aspects of electric system efficiency (+1.6%) and driving range (+3.7%); however, for the same maximal output power, the vehicle’s stack was 12.5% heavier and larger. Then, due to the existence of the turbine, the E-turbocharger led to higher performance than the single-stage compressor for the same stack size. The solid oxide fuel cell is also promising for transportation application, especially for a use as range extender. The results show that a 24-kWh electric vehicle can increase its driving range by 252% due to a 5 kW solid oxide fuel cell (SOFC) stack and a gas turbine recovery system. The WLTP driving range depends on the charge cycle, but with a pure hydrogen tank of 6.2 kg, the vehicle can reach more than 600 km.

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Overall developments in internal combustion engines suggest that the ORC system recovers exhaust heat for further use, increases system performance, and decreases adverse environmental impacts, including greenhouse gas emissions, and particulate matter. This paper presents an overview of crucial advancements in the field of ORC application in commercial vehicles for WHR and continuing developments towards clean fuels and emission regulatory standards. The is review centred on the potential of ORC technology, its applications in highway truck engines heat recovery, and most notably, the bottlenecks associated with incorporating ORC technology into commercial vehicles exhaust energy recovery. Furthermore, a range of distinct engine operating patterns is reported in respect of average speeds of trucks to assess the appropriate operating points for the chosen application.

The transport sector is presently accountable for 1/4 of total greenhouse gas released to the atmosphere, with road transportation depicting 17.8% of the total transport emissions contributing to global warming's growing threats caused by the continuous release of exhausting gases from internal combustion engines (ICEs). These exhaust threats call for improved sustainable ways of deploying fossil fuel in an environmentally friendly manner. Many sustainable solutions have been suggested recently with others already in the market; however, another promising sustainable solution is the Organic Rankine Cycle (ORC) application on-board automobiles, which is still developing stage with the prospect of entering the market soon. This paper presents the results from the thermal performance testing of an ORC system coupled to a commercial truck engine for exhaust heat recovery, which otherwise is exhausted to the environment causing pollution and other environmental threats. The test was performed to complement a study on the potential viability of installing an ORC based exhaust heat recovery (EHR) system on-board highway trucks for improving the truck's thermal performance without added fuel consumption. The testing carried out at 40% of rated load, and 1700rpm engine speed achieved 4.22kW, 3.67kW, and 5.28% for peak power output, net power output, and cycle thermal efficiency of the ORC model, respectively. These results imply that installing the ORC system on-board long-haul trucks for exhaust heat recovery has a promising future.