| Summary: | In a reciprocating internal combustion engine, as much as 35% of the energy in the fuel can be lost in the exhaust process. A common method of recovering this energy is turbocharging. Turbocharging serves mainly to increase the power density of an engine, thus, another method that was devised to further utilise the wasted exhaust energy whilst at the same time, increase efficiency. This other method is known as turbocompounding. Turbocompounding is where a second turbine is used to expand the exhaust gas down to atmospheric pressure. The energy recovered by this turbine is then fed back to the crankshaft or used to power engine ancillaries. Turbocompounding in the form of turbogenerating, where the wasted energy is converted to electricity, has been investigated on a validated engine model operating on biogas using palm oil to initiate combustion. Results have shown that overall system efficiency can be improved by 10.9% when compared to a similar turbocharged engine. The same model was then used to investigate the possibility of the engine operating on biogas using a spark to initiate combustion. Results have shown that this is possible and that the overall engine efficiency can be improved by 14.2% when compared to a similar turbocharged engine. The final stage in these investigations was to investigate the performance and the affect that the turbogenerator had on engine performance during an engine speed
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