An inventor proposed that a turbocompound diesel engine be w

An inventor proposed that a turbo-compound diesel engine be which uses an additional power turbine to extract mechanical energy out of the exhaust gas to the drive shaft. The novelty of the proposal was that much of the shaft power was to be derived from the power turbine instead of the engine. Give two comments on whether the concept is good or bad (each comment could either be positive or negative respectively).

Solution

The idea of adding power turbine is good,

1) It is possible to recover up to 20% of exhaust energy by adding power turbine in the exhaust flow gas flow line. (Please note: in modern heavy-duty diesel engine 20-25% of the fuel energy is exhausted.)

2) Power turbine helps to add approximately 10% to engine peak power output, for example: By using turbo compounding, a 400 HP engine can increase the output up to approximately 440 HP

Please note that along with above positive outcomes of turbo compound engine with power turbine, there are some issues and those are,